AutoPIPE [FAQ]

July 22, 2013, 3:55 pm

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Current Revision posted to Structural Analysis and Design Wiki by Mike Dattilio on 7/22/2013 10:55:28 PM

AutoPIPE [FAQ]

AutoPIPE,FAQ,Tutorial,selectservices


	Applies To

	Product(s):	AutoPIPE
	Version(s):	All
	Environment:	N/A
	Area:	N/A
	Subarea:	N/A
	Original Author:	Bentley Technical Support Group

Index

Question 1:

Can I add a new code material to my existing ASME B31.1 library so the program will update the hot allowable stresses for different temperatures?

Answer: Yes, a document has been prepared to describe this process. Download it now by clicking HERE .

Question 2:

How do I interpret the elevation of ground relative to the piping model for wind loading?

Answer: For pre Autopipe 6.2X , both wind design codes ASCE-7 and UBC ground is always taken as the global vertical axis coordinate = 0. For the ASCE-7 wind code, when elevations in the piping model are < 15 feet, the program defaults to an elevation = 15 feet to determine the automatic code factors. For the UBC wind code, if elevations in the piping model are negative, the automatic code factors may become very small resulting in a small calculated wind Pressure. In this case, the piping system should be moved vertically to correctly position the ground elevations relative to the global vertical axis coordinate = 0. Use Modify/coordinate and enter the appropriate vertical movement. Note: For UBC code elevations > 400ft are considered with no wind.

User wind profile: The first height field entered references the ground level of the piping/framing system, located at the point in the model with the lowest global vertical axis coordinate value. Specific height values are the global vertical axis coordinates of points in the model, which means that negative heights (or 0) are possible. Highest = point in the model with the highest global vertical axis coordinate value.

In Autopipe 6.20 or later the ground elevation field should be used to define the location (positive or negative value) where ground is located relative to the global vertical origin e.g Y = 0 if vertical axis is Y.

Note: UBC:1997 and ASCE-7:1998 codes were updated in V6.2 and now UBC Table 16-G is interpolated for intermediate values and uses values at 400 ft for higher elevations.

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Question 3:

What does [??%] mean in the code compliance report?

Answer: Intermediate stress points. A [%??}in code compliance report refers to % location of a point of the higher stress found than the adjacent run points e.g. AutoPIPE 5.03 default = 19, i.e. 19 intermediate stress points evaluated between any 2 adjacent run points or around a bend from the near to the far points.

Note: In AutoPIPE 6.0 the default for Intermediate stress points = 0 i.e. turned off.

Intermediate stress points can be important to capture points of highest stress e.g. a simply-supported Pipe with defined supports at either end has a maximum moment/stress at the mid-span but typically only the support points are defined in the pipe stress model and hence only the stresses at these points are calculated and reported.

Question 4:

What is an appropriate way to model a offshore riser?

Answer: It is important to add many points along the riser section of pipe e.g. at approximately every 8 to 10 feet to provide adequate mass discretization so the program can capture the distributed wave loading accurately across the riser pipe. Riser pipes are typically sloped at 10 to 15 deg and guide supports on the riser will be normal to the pipe axis and the reaction loads normal to the pipe can be seen in the a support forces report which shows Local and global displacement's and reactions. Note: Platform wave displacements should be applied at the platform anchor and riser guides.

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Question 5:

When do I use the Xtra hydrodynamic data?

Answer: When the pipeline does not experience the wave or current effects then under xtra/hydro data set Cm=0, Cd =0 and CL = 0 across the range of pipe selected e.g the pipe is in a J-tube, seabed pipe is buried or when concrete mattresses are applied to the seabed piping. These Hydrodynamic coefficients will over-ride the ones defined under Load/Wave.

Question 6:

What is the significance of Cm to buoyancy?

Answer: Cm under buoyancy is only used to compute added mass effects during a modal analysis.

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Question 7:

How do I model Seabed piping with concrete mattresses?

Answer: Either i) calculate "equivalent" soil properties for the concrete mattresses then insert these soil properties over this range ii) Model vstops over this section of seabed piping and use high value of friction e.g 1.5 to 2.0 plus additional distributed weight loading from the concrete mass.

Question 8:

Why is my buried piping system is showing large Displacements in the gravity case?

Answer: Soil supports are specified for most models with a final stiffness K2 = 0, although AutoPIPE can still solve this problem the results may be invalid if the nonlinear system goes a large deformation.

The soil should still have some stiffness after yield to restrain the pipe, this is accomplished by specifying a nonzero K2 value (e.g. K2= 0.01) or to include more restraints in the system or reduce the soil span in the soil identifier. Note that may also be possible that the K1 values for the soil are not providing enough stiffness to the system.

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Question 9:

A consistency check shows near-zero elements reported in the model, will this affect my model?

Answer: Try to avoid near-zero elements in a model, particularly with defined soil properties. Generally near-zero elements can be deleted without affecting the model for example if a run point is defined at the same coordinates as the near or far point of a bend then delete the run point.

Question 10:

A consistency check finds many all of the following warning messages: * * * W A R N I N G - MODEL * * * W726-7: Pipe diameter change without a reducer at point B02. Why?

Answer: These warning messages can generally be ignored and will be displayed also where two pipe identifiers are connected with the same pipe nominal diameter but with different wall thicknesses.

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Question 11:

My piping model with gaps and friction does not converge after five iterations, can I continue?

Answer: Yes, generally the default number of nonlinear iterations = 5 (in version 6.0 or earlier) is adequate for most models but for models with large gaps and friction it is not uncommon for convergence to occur after 20-30 iterations particularly with the thermal, wind and earthquake cases being analyzed in one model.

Generally if the model doesn't converge after 50 iterations, a solution cannot be found and reviewing the Model.log file will show bearing force and Displacement convergence errors at a particular support which may be the reason for the non-convergence.

Note: Default number of nonlinear iterations has been increased to 30 in version 6.10

Question 12:

When will the thermal expansion rates be updated for my code materials defined in the piping model?

Answer: Thermal expansion rates will be updated under the following operations:

Export to a batch file (*.NTL) then importing the same batch file.
Modifying the ambient temperature in the Tools/Model Options/General
Modifying the Pressure temperature across the range or complete model.
Change the number of temperature Pressure cases under edit/system (5.03) or tools/model options/General

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Question 13:

When are my material code allowable stresses updated?

Answer: Material code allowable stresses (temperature dependent) are updated under the following operations:

Changing the code material under a pipe identifier.
Modifying the Pressure and temperature across a range.

Question 14:

My ANSI flange check shows several flanges have increased from class 600 to 900, what does this mean?

Answer: The ANSI flange check calculations are recommending increasing the Pressure rating from class 600 to 900 based on the combination of the design Pressure, axial force and bending moment across the flange, these calculations are shown in appendix O as based on ASME B31.7 nuclear piping code Para 1 704.5 (a). These flange checks are known to be conservative, and using the calculated effective Pressure in ASME VIII Div I appendix 2 for flange design, a more accurate design check can be completed.

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Question 15:

How do I model code compliance cases in accordance with the DNV code?

Answer: The only relevant code compliance categories in the DNV code are functional and environmental as defined in Autopipe 6.0 as follows:

Max Equiv	Represents "load case a - Functional loads". (Von-Mises code category)
Equiv.+U1	Represents "load case b - Design environmental loads and simultaneously acting functional loads". (combined code category)
Hoop	Represents hoop pressure stress only (hoop code category)

Notice the default code combinations under sustained, occasional and expansion have brackets around these cases such that they are not required by the DNV code and have been de-selected to not print out by default in Autopipe 6.0. Also refer to code compliance calculations in the Autopipe Reference Information for DNV'81 code calculations.

RECOMMENDATIONS FOR CODE COMPLIANCE CASES FOR DNV CODE

Step1
Start with the default DNV code compliance cases.
Tools/code combinations/reset all

Step 2
If you wish to create user code combinations
a) Functional user code case e.g. Gr + T1+P1

See image below

b) Functional + environmental code case. e.g. Gr + T1+U1+E1

Note: the forces and moments for all load cases are combined at the moment level then an effective stress calculated and the allowable stress includes a factor =1.33.

Question 16:

Some of my segments have been deleted from the model and using RE-NUMBER/ALL in AutoPIPE 6.0 some of the the point names do not match the segment names e.g. a AB01, AB02 may be on segment V, how can I correct this?

Answer: Currently in Autopipe 6.0 or 5.0x , the only workaround is or perform an Edit/Cut then Edit/Paste operation.

Select the complete model using Ctrl A or Select/All points such that all points are highlighted red, then select edit/Cut (ctrl X), clicked on or type the name of a base point for typically the first anchor in the system e.g. A00 then click OK. Click yes to delete all points and the model will disappear from the screen. Select Edit/Paste (ctrl V) from menu, uncheck the box "connect two selected points", then click OK. The complete model will reappear on the screen.

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Question 17:

Why is my non-linear analysis giving unexpected results i.e large movements in the pressure case across my bellows when my tielink should restrain the pressure movement?

Answer: The tie-link has a large forward gap which under the default load sequence i.e default is "Use default sequence" is checked . Or to change the intial states i.e different load sequence then uncheck this option.

The following Initial states dialog shows the default load sequence.

i.e GR then thermal then Pressure case.

Since P1 follows the thermal case T1, the bellows moves across the gap under T1 providing "lift-off" or the gap is open then the pressure load causes the bellows to expand and moves back to take up the tie-link gap.

Further discussion on load sequencing is found in 5.0 appendices pg 190 or autopipe 6.0 Autopipe reference information under analysis considerations\static analysis\non-linear analysis\solution sequence

Note: The liftoff can be verified by checking the restraint loads for the tielink reveals Gr= -64500 and T1= 64500 confirming after the T1 case (gr+t1) no reaction occurs on the tielink hence tielink gap is open.s

A more expected result i.e pressure occuring before the thermal expansion thus the load sequence of Pressure after gravity as follows:

Giving very small movements in the vertical direction = 0.002mm across the tielink (i.e A02-A01) is probably due to any rigid anchor or support does have a very large finite stiffness in the finite element analysis within autopipe.

Question 18:

Why is displacement showing 10mm in the E1 case when my guide gaps are 5mm?

Answer: Your model is run as a non-linear analysis with the default load sequence ie. Gr then T1 then P1 as seen below in the initial states dialog.

Under a non-linear analysis the loads reported in the support and restraint reports are incremental not absolute total loads. To observe the resultant loads on supports it is important to create load combinations.

Note: There is a new option under tools/model options/result "Add Def non-code comb" when checked will automatically create many non-code combinations eg Gr+T1+P1.

eg at C23 Gr FY = -436 T1 FY= 210 i.e pipe is tending to lift off under the thermal case. but Gr+t1= -226 which means after T1 the pipe is still sitting on the support and hence 0 upward movement. If Gr Fy equal and opposite of T1(FY) then the total vertical reaction is 0 and expect to see +ve DY movement in the T1 case.

Extracts from online help autopipe 6.0

Total vs. Incremental Loading

A load case (e.g. gravity, thermal, wind, etc.) represents an increment of load, not a total load (except for gravity). Hence, pipe forces, displacements, support forces, etc. calculated for a load case represent the increments produced by that case regardless of the type of static analysis performed (linear, or nonlinear). In particular, the results for a thermal case define the changes in the forces and displacements due to thermal expansion, not the total effects due to combined gravity and thermal. In order to obtain total load effects, combinations must be defined which include the load cases that have been used to hold the specific loads of interest. "Superposition" of load cases is a commonly accepted principle for a static linear analysis. However, it is not so straight forward for a nonlinear analysis.

Nonlinear Solution Load Case Sequence

For a linear analysis, the results for each load case are obtained all at once. However, for a nonlinear analysis the results are obtained sequentially. There are two reasons for this. First, the analysis of a nonlinear system requires iteration (successive trials), and different load cases will usually require different numbers of iterations. Second, (and more important) the result for any AutoPIPE load case will generally depend on the initial state for that case. For example, the result for a thermal expansion load will generally depend on the state of the system after gravity load is applied (e.g. which gaps are open and which are closed). The solution for the gravity case must thus be obtained first, and used as the initial state for the thermal expansion case. For a nonlinear analysis, the user has the option of selecting a default load sequence or of specifying a user defined sequence. It is important to note that in an AutoPIPE analysis, each load case is an increment of load, not a total load. To illustrate the difference, consider two alternative procedures for obtaining thermal expansion effects. If analyses are performed for total loads, the steps are:

Preferred load sequence for correct loads on restraints

You may wish to run a load sequence as follows which considers the earthquake cases after the operating i.e case of GR+P1+T1 and set T1 as the initial state of the E1 case. This equally applies to wind cases also.
If more than one thermal case exists then the user may wish to set T1 as being the initial state for E2, E3 instead of T2 which may not be a operating case.

Regarding your Dx= 10mm in the E1 case since E1 follows Gr case in the load sequence and Dx = -5mm in Gr case the resultant position Gr+E1 is Dx= +5mm i.e hitting the gap hence the reaction in E1 case Fx = 179.

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Question 19:

When I perform a static analysis it stops giving the error message "E801-1 Fatal error unstable system" also if I perform a modal analysis "E801-16 Fatal error zero energy modes".

Answer: Possible Solutions are:

A segment is not connected to the rest of the model (Check the consistency check warning messages)
Tee is not connected correctly e.g Notice the point names are overlapped (point name is not clearly seen on the screen) at 2 points A and B. and/or the tee arrowhead is floating in space. Place cursor on point A and select modify/point , change point name A to B and click ok Modify convert point to run, then Modify convert point to tee, view/redraw.
A beam is not connected to the rest of the piping model with no anchor.
A beam is too 'soft' e.g shear area is too small
Flexible joint has some stiffness values = 0
Nozzle element has very low stiffness.
No anchors (rigid or flexible) in the piping system.

If frames are only used to model dummy leg supports. Then one useful tip in the future to find disconnected frame points is to batch the model i.e. file save as /NTL (batch) and scroll to the bottom of the NTL file. There is a section called BEAM NODES as seen below. This section should be empty if dummy legs are modeled correctly i.e beam from bend midpoint to dummy pipe segment.

A model has to be statically determinate which means an anchor can be traced back on every segment of pipe. In some cases the anchor does not have to be rigid but can only have 3 non-zero translational stiffnesses to prevent the pipe "floating off into space". You can also use rigid beam elements to connect pipes together which will also maintain a stable piping system.

Question 20:

What is the warning message W90-24 "current model does not match the analysis"?

Answer: This message is displayed when the model has been changed but either one or both of the static and dynamic analysis has not been re-run. If not wishing to re-run the dynamic analysis then suggest you delete the LIN & EIG files and re-run the static analysis only. This message does not affect the results.

Note that AutoPIPE 6.2 and later will prompt you for deleting these files.

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Question 21:

What are modeling techniques for special valves and loads like ice/snow loading?

Answer:

Angle Valve

Refer to online Help topic /Autopipe Workbook/AutoPIPE Modeling Approaches/Valves/Relief and Angle Valves

3 way Valve

Insert a tee (set tee component = tee, tee type = Other and SIF =1.0), insert very small run pipe then a valve from the each leg of the tee. Select the tee and run points up to each valve but not including the valve (highlighed red) and Insert/Rigid options over range (include weight = OFF, include thermal expansion = ON)

4 way Valve

Insert a tee (set tee component = cross, tee type = Other and SIF =1.0), insert very small run pipe the a valve from the each of 4 legs of the cross. Select the tee and run points up to each valve but not including the valve (highlighed red) and Insert/Rigid options over range (include weight = OFF, include thermal expansion = ON)

Prestressed springs

Define the cold preload and spring rate for the spring hanger when Insert /support/spring instead of "Undesigned".

Snow and/or ice loading

Apply either :

Select the range of pipe and apply distributed load (Insert/Distributed load) in the vertical down direction equivalent to snow or ice loading in the U1 case This is a uniform distributed load therefore enter as below:
If all the model experiences the snow loading and same pipe size then can use a user-profile wind case in the -vertical direction if calculate the equivalent snow pressure to be applied i.e snow loading in lb/in divided by the projected pipe diameter (including insulation). Note: Wind pressure default units = lb/sq.ft.

Question 22:

When I see the Lift-off warning message after the static analysis how can I find out where the lift-off is occurring?

Answer: To verify lift-off has occurred first examine the Restraint report as below:

Where the thermal or occasional (e.g. wind, seismic or user) vertical load is equal and opposite to the Gravity (GR) load (-ve vertical load) then lift-off has occurred i.e. GR+T1 vertical load = 0. This can ALSO be confirmed in the displacement or support forces report by a +ve vertical displacement in the thermal or occasional (e.g wind, seismic or user) load case as seen below :

LIFT -OFF procedure to find all the supports which are lifting off.

Run non-linear analysis and lift-off warning msg is displayed.
Clear the selection set i.e Ctrl Q or Select/clear.
Select Result/filter criteria /support.
Select the logical method = "OR"
Check the supports which could be lifting off i.e v-stops and guides. Note: springs can always move up or down.
Check Dy = on , abs = off, and "greater than" , "0.001" Note: no quotes on the values entered.
Note: This assumes Y = vertical axis change to Dz if Z= vertical axis

All the support points that match this criteria will be highlighted red on the screen or can be printed in a support forces report provided the batch report option "apply filter criteria" = yes

Note: This procedure also highlights guides on vertical lines which can be ignored Also supports with gaps in the downward direction.

Modeling Options if Lift-off occurs

Remove the support and re-run the analysis
Use "gap above pipe" and accept pipe will lift off in hot condition
Restrain the pipe from moving up e.g 0 gap above the pipe.
Replace the support with a spring.
Move the support to prevent lift-off.
Re-arrange the pipe route to prevent lift-off.

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Question 23:

For the pipe with the lowest point is at elevation -2 000 mm in the vertical coordinate but actually it is located 10 000 mm above ground, is it correct to specify the "Ground Elevation for Wind" at -12 000 mm?

Answer: Yes.

Question 24:

In the wind profile, if I specify "Global X" , does it mean +X or -X or the highest value of the two cases?

Answer: Global X = +X only.

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Question 25:

How I can determine if a flange in the piping system is under tension or compression with AutoPipe?

Answer: If you check the box for ANSI flange check then print the Flanges report it will only show tensile axial load. If the ANSI flange report shows axial load = 0 then flange under compression.

Question 26:

How do I model socket weld fittings?

Answer: It is recommended based on the intent on many ASME codes to use conservatively an SIF value = 2.1.

ASME Codes state the following regarding socket welds:
B31.1 use 1.3 for socket welds with no undercut, and 2.1 for all others.
B31.3 states "2.1 Max or 2.1 T/Cx but not less than 1.3. Cx is the fillet weld leg length".
B31.8 states "2.1 Max or 2.1 T/Cx but not less than 1.3."

To apply this SIF to all bends and Tees perform the following:

Select/Bends to highlight all bends in the model, then Select/Tees to highlight all bends in the model, then Insert/xtra data/User SIF, Inplane SIF =2.1, Outplane SIF =2.1, Override all other SIFs at this point = unchecked (i.e maximum SIF used if automatic SIF > 2.1), Flexibility Factor = 1.0 (no flexibility).

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Question 27:

Are there any changes I need to make after I rotate my model about the vertical axis?

Answer: Yes update the following to reflect the new model orientation.

All imposed support and anchor displacements.
Forces and moments are applied in a global direction and may also need updating.
Supports other than springs, constants, guides and v-stops e.g inclined may need to be modified so the restraint direction relative to the pipe is maintained.

Question 28:

Do I need to change the weld factors defined in the pipe properties screen?

Answer: These are only used for the TDK and SPC piping codes and should be left as the default value = 1.0 for all other codes. Refer to the Autopipe help "Weld Factors" for more in-depth discussion.

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Question 29:

How do I model the offshore code compliance to B31.4, B31.8, BS8010 or CSAZ662 section 11?

Answer: A document has been prepared to describe this process. Download it now by clicking HERE .

Note: In AutoPIPE 2004 edition (v8.50) offhsore codes B31.4 chapter IX, B31.8 Chapter VIII and CSA Z662 section 11 codes were added.

Answer: The vertical leg in the piping effectively becomes a restrained piping system between the hanger and an anchor or another vertical support above or below the current hanger support. Therefore the large reaction on the vertical leg support in the Hy case is due to the combined effects of pressure extension, any hydrotest thermal effects(usually taken at ambient) and deadweight under hydrotest case and fluid+pipe weight loads under the GR case. The pipe wants to expand due to pressure but is restrained by the locked spring hanger therefore generating a large pressure reaction.

Currently, the hydrotest load case in AutoPIPE is only a static linear solution. In other words, support gaps are considered closed and support friction is ignored. In the hydrotest load case, AutoPIPE automatically converts all designed and undesigned spring and constant hangers to a rigid hanger (V-stop) to simulate locked hangers. Gravity, pressure, and thermal loads (if any) are combined to simulate hydrotest loads.

As mentioned the Hydrotest includes rigorous pressure analysis which for high pressure systems causes significant pressure extension in the pipe e.g if remove the v-stop at A03N and run the hydrotest shows upward displacement of 0.005". i.e with the system pumped up with 4950 psi pressure.

With the v-stop at A03N it is assumed locked and generates this upward load = 27482lb trying to resist the pressure extension.

Note: If it is considered that the hanger rod assembly is not rigid in compression (i.e. some slack which is not unreasonable) then it would better to use a separate model with GR, P1 (Pressure Analysis = Checked) and T1 as hydrotest loads, and enter upward gaps for the v-stops then run the analysis as non-linear. This will allow the pipe to move up and not be restrained.

Note: To include the axial stress due to the pressure analysis cases (P1 - P3) in the calculation of longitudinal pressure stress (may be significant for high pressure systems), under tools/code combinations/longitudinal pressure, option "Include rigorous pressure stress" = checked. By default this option is OFF.

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Question 31:

I am performing a steam hammer analysis but when should I use ZPA correction method under Time History analysis?

Answer: We recommend to perform two analyses, one with ZPA and one without. For flexible legs (legs with flexible or no axial supports) use no ZPA correction. If the system has pipe legs with rigid axial supports, use ZPA correction to determine realistic loads on these axial supports. Note: ZPA can be very conservative for flexible legs.

Question 32:

How I can be sure I have correctly modeled my fluid transient?

Answer: Some key points to check modeling a fluid transient :

Define the flow rate with correct sign. Flow rate is positive for negative pressure rise. Note: When a pump is shutdown, there are two shock waves generated. A positive pressure wave on the suction end and a negative pressure wave on the discharge end are generated. The maximum possible negative pressure wave is equal in magnitude to the pump discharge pressure(Ps) less the liquid vapor pressure (Pv). The pressure wave amplitude is calculated in AutoPIPE using the Joukowski formula. DP = Fluid density*Fluid velocity*speed_of_sound
This pressure wave = dP should be less than Ps-Pv to avoid cavitation. This condition should be avoided since the Autopipe results will be invalid. Similarly the pressure rise will be positive upstream of a closed valve and negative downstream of an open valve.
Typically use default SINE rise function
Define time history duration as 1st period (1/first modal frequency, hz) + transient duration (as shown in the THL file).
When click ok to the fluid transient check the red highlighted sections of piping are correct.
Run the modal analysis with cut-off frequency at least 100 to 150hz. Recommended to perform modal followed by time history analysis at both cut-off frequencies to confirm the solution has converge i.e. time history results are similar.
Run time history with and without ZPA correction. See Q31.

Note: Recommend to set under tools/model options/Edit "Mass points per span" = A to allow the program to automatically perform mass discretization on your model for improved accuracy for the dynamic analysis.

Support solution

Flexible is better. The restraint should only be stiff enough to sufficiently attenuate the low frequency gross deformation.

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Question 33:

Is marine growth thickness included for buoyancy loads?

Answer: No Autopipe does not consider marine growth thickness (under load/wave) in the calculation of buoyancy loads but it does consider insulation around the pipe in the buoyancy load which can be used to simulate marine growth over a section of pipe and also capture additional weight of the marine growth.

Question 34:

It is optional to include corroded wall thickness, axial force and torsion in the DNV stress calculations, what should I use?

Answer: Yes for the DNV code, the program defaults to Use nominal thickness = checked, since this code explicitly uses nominal thickness for stress calculations. However other codes default to use corroded thickness for stress calculations which is more conservative. i.e for longitudinal pressure stress and corroded section modulus used in bending stress calculations.

Refer to the following help topic for code calculations.

Autopipe 6.X "Online help topic Autopipe Reference information / Code Compliance Calculations/ DNV" By default axial force and torsion effects are NOT included for DNV but it is recommended to include them for offshore risers especially when the line pressure is high e.g > 500psi.

To include axial force and torsion check the following options.

Pressure Analysis = checked (under static/analyze)
nclude rigorous pressure stress =checked (under Tools/code combinations /longitudinal pressure) to include axial pressure stress in the longitudinal pressure stress
Under Tools/model options/results:

Include axial force = checked
Include Torsion = checked

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Question 35:

Can Autopipe open an Caesar input file?

Answer: Autopipe can only open a Caesar neutral file (*.cii), In Caesar convert the caesar model file to a neutral file from the main menu , Tools/external interfaces/Caesar II neutral file.

Question 36:

How do I calculate the DNV 2000 tension terms?

Answer: In accordance with DNV 2000, AutoPIPE currently can output the following Local Forces and Moments results:

Note: Local forces convention
-ve = tension
+ve = compression

With buoyancy defined under Load/buoyancy the hydrostatic forces are calculated and automatically included in the GR case.

GR = N + PeAe
P1 = internal pressure forces in pipe wall not including PiAi (capped pressure term).
GR + P1- PiAi = S = N + PeAe - PiAi

Since the sign conventions for S (Effective axial force) , N (True axial force in the pipe wall) , PeAe is consistent with respect to tension or compression i.e signs are automatically calculated by the program and included in the GR and P1 load cases.

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Question 37:

How do I capture marine growth weight?

Answer: Marine growth thickness usually varies with depth therefore it is recommended to add a distributed load down the riser which can be triangular profile to simulate the varying thickness vs depth.

Note: There is no marine growth above mean water level, i.e., marine growth is assumed zero above water level for drag and inertia wave calculations.

Question 38:

I am carrying out a modal analysis on my offshore riser and what value of Cm should I use on the buoyancy screen?

Answer: Referring to the On-line Help a "value of Cm (coefficient of inertia) for cylindrical bodies in a incompressible, frictionless fluid is 2.0".

Also refer to DNV 1981 A.3.2 and fig A.7 which shows added mass coefficient as a function of M/D where M is distance from a fixed boundary. If no influence from a fixed boundary then use Cm = 1.0 otherwise Cm = 2.29 to 1.0. Most of offshore users use default value = 2.0.

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Question 39:

How do I model a rigid anchor in the local pipe direction?

Answer: Enter 3 translational and 3 rotational stiffnesses in local direction for a horizontal pipe, add 1 rotational support about global Y direction (i.e local Y = Global Y), 2 inclined rotational supports (calculate the cosine restraint direction with respect to the pipe direction), linestop (forward and backward gaps = 0) and guide (left, right, up and down gaps = 0).

Question 40:

How do I model a large sweep bend with radius = 50ft?

Answer: Assuming the bend has supports along it then model the bend as series of straight pipe run sections with offsets calculated as a segmented miter bend. Alternatively enter the bend with radius = 50x12 = 600 inches (for ENGLISH units, by overriding the word Long or Short in the radius field. Radius units is displayed in the lower right of the main AutoPIPE window) and insert soil over the large bend with large value of downward soil stiffness, vertical up and lateral stiffness = 0, longitudinal stiffness = 0 (or some nominal value to include some frictional resistance).

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Question 41:

Do I need to run a static analysis after my hanger selection?

Answer: Yes since the hanger selection only does a free thermal loading whereas the static analysis considers the spring hanger preload and stiffness.

Question 42:

What are the +/- points displayed in code compliance and forces/moments reports?

Answer: +/- points are displayed in the code compliance report:

pressure or temperature change
Pipe identifier change

+/- points displayed in forces and moments report:

Flange points, supports, additional weight, concentrated force, tee point and uniform distributed load.

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Question 43:

Does Autopipe include axial stress for ASME B31.1 and B31.3?

Answer: Both ASME B31.1 and B31.3 codes do not give explicit stress calculations for axial stress but for some cases e.g buried pipe, low modulus systems like FRP and high pressure systems it is recommended to consider axial stress. To include axial stress for all loadcases except pressure then use the option Tools model options /Results "include axial force" = checked. The sign is ignored when adding axial stress to the code stress calculation since this stress calculation is a gross longitudinal stress in the pipe. This is consistent with other pipe stress programs.

Question 44:

Can I apply local displacements to my guides?

Answer: Only the component of the global displacements in the local restraint direction i.e normal to the pipe for a guide is applied to the restraint. Hence for a skewed pipe, a local displacement can be resolved into global components and applied to the guide.

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Question 45:

Which side of the pipe at a run point are the forces and moments are reported?

Answer: Global Forces and moments convention.

Refer to online help topic Figure H-3 on Autopipe 6.0 reference information/ results interpretation/ Pipe Forces and Moments: Global Option

Check the forward direction of the pipe and imagine all the pipe upstream of the reported run point is removed then local or global forces and moments reported (-ve point) will be those acting on the downstream pipe to keep it in equilibrium.

For bend and tees and support points and - and + points are reported by the program i.e Loads before /after the point

For example: To resolve the actual forces and moments at a tee defined with 3 segments. The branch segment direction is into the Tee and both the header segments are created away from the Tee. Then the global forces and moments at the tee can be read directly for the branch point but the sign must be reversed for the global forces and moments reported on the two header tee points.

Note: For skewed piping connecting equipment, you will generally consider the local forces and moments acting on the run point if the run direction is not aligned to the global axes. Enter option Tools model options /Results "Force (Global/Local)" = L for local forces and moments.

Question 46:

How does Autopipe calculate the Pressure Extension & Pressure Thrust forces?

Answer: Autopipe calculates the pressure thrust based on cap pressure force - poissons effect i.e using inside diameter for the poissons term. This term is at the analysis level acting on the inside diameter and not a code compliance hoop stress term which uses outside diameter.

Pressure thrust reaction at anchor. Rpressure = p.Ai - v.p.Di/2t x As where Ai is the internal pipe area and As is the X-area of the pipe, t is the wall thickness.
Pressure extension Ext = (p.Ai/As/Elong - v.p.Ri/t/Ehoop)*tangent length

Note: Autopipe does not report the cap internal pressure load at an anchor unless it is unbalance thrust across a flexible joint with the pressure analysis option checked when performing a static analysis.

Note: The program calculates displacements then back-calculates forces and moments from the stiffness matrix equations which many times can be difficult to manually re-produce.

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Question 47:

How can I simulate soil settlement on part of my piping system?

Answer: If the piping system is above ground then at the v-stop and guide supports we recommend to apply settlement displacement in a user case e.g U1. This will allow the soil settlement to be observed as a unique loading. Then edit the sustained code case combination SUS + Gr to include U1 i.e. the settlement is added to the sustained stresses.

If the piping system is buried then the imposed displacement at defined node points (with soil) would give the soil settlement profile. In other words, the base of each soil spring is subject to a displacement interpolated from adjacent nodes with imposed displacements. Hence select the range of points and Insert/xtra data / imposed support displacement = settlement value in the U1 case.

To consider settlement for hanger selection, the following is recommended:

Using model A, add the settlement in the T1 case and run the hanger selection to size the spring.
Copy model A to Model B.
Using model B, change the settlement from case T1 to case U1 and create user non-code combinations using U1 and add U1 into the sustained stress case GR+MaxP as above.
Using a non-code combination e.g. GR+T1+U1 the combined movement and load on the supports including any spring hangers can be evaluated.

Question 48:

Can I model a Sway Brace?

Answer: You could use an inclined support in the direction of restraint and enter the stiffness corresponding to the sway brace spring stiffness. Add xtra data/conc force (i.e sway brace preload ) in the direction of restraint in the GR case such that non-code combination Gr + E1 will still have the preload.

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Question 49:

Can I model my pipe shoe supported on a spring can with friction?

Answer: Yes insert a spring at the pipe location and run a hanger selection then change spring to inclined support with the calculate hanger spring rate, 0 gaps and add friction e.g 0.3. Insert concentrated force in GR case = hanger preload at this same point.

Question 50:

Why are all my dynamic results positive?

Answer: All results from any dynamic analysis are always signless That is positive displacements, forces and moments, support loads etc i.e. although dynamic loads are signed during the analysis phase of the solution, the results are without sign. The reason is that the results are maximum values over time and represent an envelop of maximum values. Hence in many piping configurations applied loads - whether +ve or -ve in direction will give an identical result.

Although all dynamic results are always reported as positive including time history, support loads should always be considered +/- for design but be aware that the restraint load will always be in the direction of the restraint and therefore has a vector direction (therefore signed) not shown in the reported restraint report for dynamic loads (always positive). Hence it is also not recommended to create user non-code combinations of static + dynamic loads. All stress programs have this limitation.

Also refer to online help - Autopipe reference information/Results Interpretation click on Dynamic Support Forces Results. Note: The Dynamic load analyses including time history are always linear i.e non-linear features such as friction, gaps, soil yielding are ignored.

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Question 51:

Can I create a isometric model to use in AutoCAD or Autoplant?

Answer: Yes there are 3 possible DXF formats which can be exported from Autopipe.

DXF file export in either 3D or 2D format and import to Autocad R14 or later.

TRUE 3D DXF model (File save as DXF/ Tools/Settings/DXF Drawing Border + include 3D model = yes )
3D LINE ISOMETRIC DXF model (File save as DXF/ Tools/Settings/DXF Drawing Border + include 3D model = no)
2D DXF model (Set the view mode = line then select Print graphics As Autocad DXF)

In the 3D formats a) & b) when the DXF file is first opened in Autocad the view is a plan view by default with the drawing sheet orientated to this plan view which is consistent with 3D CAD drawings. We recommend use the 2D DXF format for a 'flat' 2 1/2D Isometric view - unfortunately no drawing border but can be copy/pasted from standard CAD drawing. OR Create a drawing border in paper space to frame all the views you want on the 3D model.

Dimensions and node numbers can be sized under tools/settings/DXF export drawing border e.g change text height = 4 inches. Autopipe does not support dimensioning lines only length offsets shown on the pipe centerline.

Question 52:

Why does the legend for the interactive code scan show a maximum value = 1.0 for stresses?

Answer: When the stress criteria (not ratio) is selected in the Result/code scan, the color coding is based on the ratio of the calculated stress divided by the largest stress value in the model. The element is colored based on the highest stress ratio at either end of the element.

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Question 53:

My B31.3 code stress is showing an overstress in the hoop stress (Max P) case?

Answer: Suggest check the mill tolerance, corrosion allowance and pressure at the points of overstress.

Note: Miter bends have a different hoop stress calculation to straight pipe. Autopipe is based on the more conservative B31.3 equation 3a.
Note: Autopipe always defaults to Y factor = 0.4 (i.e carbon steel <=900F), for different materials and/or higher temperatures change the Y-factor under Tools model options /Results "Y Factor". Default weld efficiency factor = 1.0.

Autopipe 6.X Online help topic Autopipe Reference information / Code Compliance Calculations/ASME B31.1 hoop stress calculation.

Question 54:

I open my archived model and it appears blank. Why?

Answer: When files are archived to read only media like CD-R they are assigned a file attribute = R (read only) but Autopipe requires the model file (*.DAT) to have a file attribute = A (archive).

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Question 55:

Sometimes my Autoplant valves imported from the PXF neutral file have zero weight. Why?

Answer: Valve weights are read from the Autoplant PXF fil. If no weights are available in the AutoPLANT model then Autopipe will attempt to set the weight based on its own valve library using the valve size, valve type e.g. gate, globe etc and pressure rating e.g 150, 300 etc. If any of these three criteria do not exist e.g ball valves are not in the default valve library then the weight will be set = 0.

Question 56:

How can I change my Y-vertical axis model to Z-vertical?

Answer: Autopipe was not designed to change the vertical axis for an existing model since coordinates and supports (except springs, v-stops and guides) may be messed up.

However the model can be saved as a Autopipe neutral NTL file (File/save as batch NTL). Open this NTL file in Notepad.exe then change Y-vertical model to Z-vertical model by changing the Y to Z in the CTL line below Save the NTL file and in Autopipe select File open/ batch NTL.

When the model is imported back into Autopipe it will have to be rotated (possibly other transformations) to orientate the model as it was before and then check all the supports are correctly orientated.

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Question 57:

Why does my bend look disconnected from the pipe on the screen?

Answer: Bends may appear disconnected but this is only a plotting limitation and to check bend connectivity with the piping system, use the keyboard left/right arrow keys to move the cursor along the pipe and around the bend.

Question 58:

How can I define a branch SIF using B31.1 Fig D-1 sketch d)?

Answer: Autopipe currently does not calculate to Fig D-1 B31.1 but the SIF can manually be calculated then applied using insert/xtra data/user SIF on the branch side of the Tee only. The B31.1 branch effective section modulus is calculated by Autopipe = pi rm^2 te since rm is same as rb on Fig D-1 B31.1 (d) then suggest insert a small run with different pipe identifier having a thickness when used in the section modulus calculation will be equivalent to tb. Where te = smaller of tn or i.tb hence equivalent branch thk = actual tb/ SIF calculated from Fig D-1 B31.1 assuming i.tb is smaller than tn.

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Question 59:

Does my expansion joint include contents weight?

Answer: Autopipe does not automatically include the contents weight across a flexible joint therefore this weight must be included in the total component weight. Also valves and reducers do include contents weight but nozzle elements do not.

Question 60:

Why do I I keep getting a warning message "W831-1, Combinations include cases not analyzed"?

Answer: This warning message "W831-1" means either a user non-code or code combination has been created but a load case defined in that combination has not been analyzed. Note: When a user combination is defined both the non-code and code combination list is fixed i.e. if additional loads cases are analyzed then default code and non-code combinations are not created. To have the program create the new default combinations then select Tools/code combinations/reset all or Tools/non-code combinations/reset all, this will remove any user combinations.

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Question 61:

How do I make a mirror copy of a section of piping?

Answer: To make a mirror copy :

Select the pipe section to mirror copy.
Edit / copy and select appropriate base point.
Edit /paste to and paste the copied section to the new location.
Select the copied section
Edit/scale Enter -1 to mirror those offsets e.g of mirror about the Z-axis then enter -1,1,1 i.e reverses all the -ve X offsets

Question 62:

How do I define the coefficient of lift for wave loading?

Answer: The lift coefficient (CL) is typically applied only to the seabed piping and is only defined under Insert/xtra data/hydrodynamic data. By default CL = 0.

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Question 63:

Can you provide any references for buried pipe design?

Answer: Some references are listed below:

Buried Pipe Design by A.P. Moser Publisher: McGraw-Hill Reference: Guidelines for the Seismic Design of Oil and Gas Pipeline Systems - ASCE Committee on Gas and Liquid Fuel Lifelines -1984

Soil Properties : Testing,Measurement and evaluation by Cheng Liu and Jack Evett
ISBN 0-13-0200069-7
Publisher : Prentice Hall

Soil Mechanics in Engineering Practice by Karl Terzaghi
Publisher : John Wiley & Sons

Essence of soil Soil Mechanics and Foundations : Basic Geotechnics by David F Mc Carthy.
Publisher : Prentice Hall.

Guidelines for the Design of Buried Steel Pipe - July 2001 by ASCE Click the following link.

http://www.americanlifelinesalliance.org/pdf/buried_pipe.pdf

Question 64:

How do I model the discharge piping accurately relative to my suction Piping?

Answer: To model the discharge piping accurately follow the steps below:

Place the cursor on the suction point
Insert / Segment (see screen bitmap below)
Enter New first point name e.g AY00
Enter suction point in the "Offset from which point" e.g AW07
Enter offsets DX, DY, DZ
Enter or select pipe identifier for the discharge piping
Click Ok
Then continue building the new discharge segment

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Question 65:

How do I model different parts of the piping system inside and outside a building for wind loads?

Answer: You will need to model the section of pipe inside the building as a different segment to the outside piping.

On the main wind dialog, uncheck the option "All segments exposed to wind" and after all the wind loads have been defined, a segment dialog will appear which you can select or de-select the segments which will have wind loading applied to them.

Question 66:

What does LOC mean in the General Stress Report?

Answer: General Stress location Total stress is calculated every 15 deg and the zero degree axis for the total stress location angle in a clockwise direction around the pipe.

The 0 degree axis is the local axis of the pipe cross-section, i.e. perpendicular to the pipe axis, corresponding to the resultant in-plane bending moment. For example, if the local bending moments are my and mz, then arctan (my/mz) is the location of the 0 degree reference axis for the general stress location relative to the local y axis.

Note: For straight pipe in-plane bending is arbitrary since no plane of bending like an elbow.

Axial stress: fx/A
in-plane bending stress: my/Z
out-plane bending stress: mz/Z

where,

fx = local axial force
my = local in-plane bending moment
mz = local out-plane bending moment

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Question 67:

How can I determine axial (tension or compression) and bending stress in the pipe?

Answer: Refer to the general stress report .

Axial stress = 1/2 x(sum of the longitudinal Max and min stresses)
Stress convention
+ve = tension
-ve = compression

Note: Local forces convention
-ve = tension
+ve = compression

Note: P1 force does not include the capped internal pressure force. However this pressure force PiAi can be manually subtracted from the Local-X P1 force to give a true P1 axial force i.e Total P1 = P1 - PiAi

Resultant Bending stress = 1/2 x(longitudinal Max - longitudinal min stresses) (always +ve stress since using resultant bending moment)

Question 68:

How do I model a ball joint with high inertial moment stiffness?

Answer: The conservative approach would be to add a constant moment at one end of the flexible joint.

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Question 69:

Please confirm the recommended value of the added mass coefficient, Cm for a circular cylinder according to DNV Rules for Submarine Pipeline Systems - 1981 - Fig. A.7.

Answer: Sorry for the confusion Cm and Ci are inter-changeable in Autopipe i.e mass (inertia) coefficient in Buoyancy, Wave Load Hydrodynamic Data dialogs.

So Autopipe (Cm)is inertia coefficient but DNV 81 (Cm) is the added mass coefficient.

Where Autopipe Mass coefficient (Cm) is the inertia coefficient(i.e. 1 + added mass coeff) [where added mass coeff = Range 2.29 to 1.0 (no fixed boundary) as per DNV'81 Figure A.7), hence Autopipe Cm(Ci) = 3.29 to 2.0]

We will be updating the program and help in v7.0 to clarify the definition of these coefficients.

The only Cm (inertia) used in the modal analysis is the Cm value in the buoyancy loading dialog.

Question 70:

How do I define one constant Hydrotest pressure over the whole model?

Answer: The hydrotest pressure defined under Load/hydrotest dialog is taken as the pressure (usually case 1) multiplied by the factor e.g. 1.5 at each point hence for case 1 if different pressures in the system e.g branch line then the hydrotest pressure will be different for the branch.

A workaround if on hydrotest pressure for all points then define a dummy temperature and pressure case 2 which has one constant pressure for the whole model and no temperature loading i.e ambient and define the hydrotest pressure based on case 2.

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Question 71:

What are the Participation Factors and the Captured Modal Mass in the frequency report?

Answer: The participation factor is a measure of the importance of the mode in earthquake type load. The captured modal mass is another way of quantifying the importance of the mode and the two are related. The captured modal mass percentage tells how much of the response is atributed to a particular mode and also tells on the mode orientation (X,Y or Z). The sum of modal masses should be 100% if all modes are counted. But since many modes are not counted, the sum is less than 100 and hence the importance of the ZPA and missing mass options for dynamic analysis. Please refer to the topic "Missing Mass and ZPA Correction" in the online help for more information.

The participation factors are calculated from the product of the mode shape, the mass matrix and a vector of ones. For mode i the participation factor is calculated as:

Participation_Factor_i= Transpose(ModeShape_i) * MassMatrix * {1}

The mode shape is mass normalized. The above equation is used three times for X, Y and Z directions.

The mass participation report illustrates how sensitive each of the piping system's modes are to the dynamic loading. High modal participation factors indicate that the mode is easily excited by the applied dynamic forces. If subsequent displacement reports indicate high dynamic responses then the modes having high participation factors must be dampened or eliminated. Once a particular mode is targeted as being a problem, it may be viewed in the mode shape report, or graphically via the animated mode shape plots.

Question 72:

When should I perform a pressure analysis?

Answer: Some guidelines are a pressure analysis should be performed when some significant strain due to pressure can result for example:

Systems with expansion joints.
Low modulus piping e.g plastic or FRP
Large pressure on steel piping systems e.g >500psi
Large diameter e.g >=30" diameter with moderate pressure.

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Question 73:

The Autopipe help states "When the rise time several times larger than the 2L/a time, the calculated pressure rise in AutoPIPE might be conservative. For this special case, the use of a fluid simulation software is recommended if P2 case is critical." What does this mean?

Answer: Check for maximum surge pressure (static (362)+ rise (228) =590 psi). This should be added as a second pressure case (P2). Use Tools/Model Options/General and set number of operating cases to 2. Use Select/All Points and follow by Modify/Pressure & Temperature and set design pressure for P2 to 590 psi. When the rise time several times larger than the 2L/a time, the calculated pressure rise in AutoPIPE might be conservative. For this special case, the use of a fluid simulation software is recommended if P2 case is critical and causes an overstress condition in the pipework.

If P2=590 psi governs the design, that is critical, the use of fluid simulation software is recommended since AutoPIPE value would be too conservative.

Question 74:

My seabed piping shows a large unexpected displacement. Can you please explain?

Answer: When the 2nd soil stiffness (K2) is set to zero, the pipe displacement can be large or can cause instability as the soil yields. Most soils especially sand have a parabolic force-displacement shape and a larger K2 value is justified but it is conservative to assume a small K2 value. It is advisable with a model so sensitive to changing the K2 value, to examine the soil displacements and forces for more detailed evaluation of yielding e.g. as seen in the soil forces report the horizontal soil force is about 176 kg/m at A78 compared to the P1 value is only 145.8 kg/m hence the soil does not have enough lateral resistance to support this pipe.

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Question 75:

How do I enter cold spring into my main steam model?

Answer: Cold Spring or Cut short in pipe stress programs can only be applied as a fixed displacement value not a percentage of thermal expansion since the amount of cold spring it is unknown until the completion of the static analysis. This cut short value is equivalent to removing this amount of pipe from the overall length. Therefore a previous static analysis run should have been performed

The maximum thermal expansion in all 3 global directions is found from a static analysis between 2 anchored points then the cutshort is calculated in the 3 global directions and applied generally at one location. To apply cutshort in 3 directions it is necessary to insert a small pipe in the direction of these 3 global cut short values e.g. Dx = 3", Dy = 4" , DZ = 5" then apply the cutshort as a resultant value e.g. 7.07" at the end of this short pipe run.

Important Note: Piping codes do NOT permit reducing sustained or thermal stress range using cold spring. Therefore it is recommended to apply the cut short in Autopipe using the User load case = U1.

Create user Non-code combinations = Gr+P1+T1+U1 and GR+U1 to examine the resultant loads on equipment and supports.

Question 76:

Given that point A11 is the TIP of a long-radius bend, how are the near and far points related to A11 N-, A11 N+, A11 F-, and A11 F+?

Answer:

A11 N- = on the straight pipe adjacent to near point
A11 N+ = on the bend side adjacent to near point
A11 F- = on the bend side adjacent to far point
A11 F+ = on the straight pipe adjacent to far point

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Question 77:

When I insert a midpoint there is a big difference in the natural frequencies, can you please explain?

Answer: It is important you perform all modal and dynamic analyses with automatic mass discretization to capture the dynamic mass in the system.

Recommend you set under tools/model options/Edit "Mass points per span" = A to allow the program to automatically perform mass discretization on your model for improved accuracy for the dynamic analysis.

Question 78:

When performing seismic analysis, can AutoPIPE do multi support excitation?

Answer: No but it is common to envelope spectrums to provide a maximum response. This feature is available in AutoPIPE 2004 (v8.6).

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Question 79:

How can I print an echo of the input response spectra (load)?

Answer: AutoPIPE cannot at this time print an echo of the input response spectra. You can, however, manually send the spectrum files (.spc) to the printer.

Question 80:

Where do I input stress range reduction factor?

Answer: Tools/Model Options/Results...right hand column, second line down.

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Question 81:

How can I look up the units for a flexible anchor for translational and rotational stiffness?

Answer: Select unit in question and read units designation in lower right hand corner of screen.

Question 82:

I have been working with AutoPIPE 8.05.01.11. How do you print in version 6.3 when there are no grids?

Answer: Go to Results/Output Report and select which items you want to print. Then in the Output Report go to File/Print.

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Question 83:

Can AutoPIPE run a flange check and if so, how?

Answer: Yes, AutoPIPE can run a flange check. In the flange dialog box check "ANSI Check", select the flange class and material and select the gasket material. AutoPIPE automatically runs the flange check.

Question 84:

I am looking at a tutorial for water hammer called apham1. I have noticed that between A06 and C00 there is, essentially, a split between the supply and discharge lines of the imaginary pump (each is anchored and flanged). I didn't know this could be done. Could you help me to get this same type of arrangement set up for a similar project I am working on?

Answer: Select the suction nozzle where you want to add a discharge nozzle. Press F3 and note the coordinates. Using your pump drawing calculate the coordinates of your discharge nozzle. Go to Insert/Segment and set the first point number (i.e if new segment is C then first point would be named C00), and input the discharge nozzle coordinates. Insert you anchor and proceed.

Note: If the pump is changed or if you need to adjust the position of the discharge then Select the discharge segment and use the Edit/Move command.

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Question 85:

When coding a tie/link for an expansion joint what is considered gap forward and what is considered gap backward?

Answer: The gap forward will allow the near end of the joint to move forward (compress the joint). The gap backward will allow extension of the joint.

Question 86:

How do you close a loop?

Answer: Go to Insert/Run. The dialog box will show you the existing point (from) and the next point (to). Change the "to" point to the one you want to close with. Enter "OK" and the loop will close.

Note: A segment cannot be connected back on itself e.g. to form Ring manifold a 2nd small segment is required to close the 'Ring' using Insert /Segment.

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Question 87:

I am working on a system which a two phase liquid. For the stress analysis, which specific gravity should I use? Should I consider the true representative by getting the average or just use the higher specific gravity?

Answer: For slugging flow induced by the two phase flow, the SG of the liquid should be used.

Question 88:

Does AutoPIPE assume the contents of the pipes are full of water? If so, is there a setting available to modify the specific gravity (or other item) to model a different fluid?

Answer: Go to Modify/Properties of a Pipe Identifier to enter the fluid Specific Gravity.

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Question 89:

Is there a way to easily modify the allowable stress for the custom piping I have put into the model? I am using Code B-7159.

Answer: For Code BS7159 the Allowable Stress is not entered. The Design Strain is. The Design Strain value is used for the calculation of the allowable design stress corresponding to the operating load condition. The default value is set to the cold design strain as defined in the Pipe dialog. If a load combination does not include any operating loads, then the smallest design strain of all the operating loads will be used. Go to Modify/Pressure & Temperature for the operating design strain and Modify/Properties of a Pipe Identifier for the cold design strain.

Question 90:

Please explain the $T1 and $T2 load case data?

Answer: Loadcases T1 and T2 already existed under a linear analysis and AutoPIPE could not create duplicate loadcases with the same name. So, it renamed the cases as $T1 and $T2. Please note that when you ran a non-linear analysis and established user cases T1 and T2 the other T1 and T2 cases did not exist. But when you ran a linear analysis, and T1 and T2 were created. AutoPIPE renamed your existing user T1 and T2 cases to avoid a programming conflict.

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Question 91:

Seismic load needs to be run with friction. How do I turn it on?

Answer: Go to Analyze/Static and turn on Gaps/Friction/Soil. Select OK. Uncheck the Ignore Friction for E1 to E10 box and select OK again.

Question 92:

How do I change a temperature over a range?

Answer: Select the starting point of your range and, while holding down the Shift key, select the end point of your range. Go to Modify/Pressure and Temperature and type in the new temperatures. To view go to View/Show/Temperature.

Note: Modify/Operating Load by value allows any temperature or pressure in the complete model to be changed to a different value.

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Question 93:

In the Hanger Selection Analysis dialog, it is displaying V-Stop as supports whereas the user has spring hangers. What criteria does it use to determine the supports?

Answer: If the movement at the location where you want the spring is less than the value in the Rigid Hanger Criterion box, the program will enter a V-stop. The default value is 0.1 inch. To always have a spring selected then change this value to 0.

Question 94:

If the modal displacements are a unitless number, what is their value based on?

Answer: The modal displacements are mass normalized which means they divided by the the following matrix transformation.

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Question 95:

How do I hide node numbers?

Answer: There are three ways to Hide/Show node points.

Hold down Ctrl and depress N.
Click the toolbar icon with E-15 on it.
Go to View/Show/Point Names.

Question 96:

How do I print to AutoCAD DXF?

Answer: Go to File/Save As/DXF

Note: Tools/Settings/DXF Export Drawing border provides many options to change the drawing sheet size, units, text size, line thickness and drawing margins.

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Question 97:

How to increment point numbers by 5 instead of the default increment of 1?

Answer: Tools/Model Options/Edit and change "Default point name offset" to 5.

Question 98:

I am looking for a quick way of changing the piping orientation and I do not want to start to input the model again. I would like to change the orientation of the horizontal leg to start from the X and Z plane at 45 degrees.

Answer: Highlight the area in question by selecting the first point and holding the shift button down while selecting the second point. Go to Edit/Rotate and input the base point (the point that you want to rotate about) and enter OK. Input the number of degrees rotation desired and the axis of rotation and enter OK.

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Question 99:

What is the method for stress analysis of pipe settlement when loading traffic?

Answer: After modeling soil points, use support displacements at piping points which have soil defined over them to simulate the soil settlement and then apply a uniform load to simulate the traffic loading.

Note: If no Soil is defined then insert V-stops with applied support displacement = soil settlement.

Question 100:

Is there an easy way to change temperatures over a range using the input grids?

Answer: See steps below.

Using the Pres/Temp/Pipe ID tab of the Input Grid enter the temperature at the first point that you want to change.
Hold down the Shift key, select the last point in the temperature range. This will highlight the range of cells.
Hold down the CTRL key, press Enter, and the temperatures over that range will be updated.

Note: Using the CTRL key can do multiple unconnected selection ranges like EXCEL. The new temperature can be entered after the range is selected also.

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Question 101:

I am running 12 thermal loadcases (Code B31.1). I noticed in the code combinations that the range from ambient to T1....T12 are considered, however, the total range for all twelve cases are not shown. For example only "T1 to T2"; "T1 to T3" and "T2 to T3" are shown.

Answer: Go to Tools/Model Options/Results and enter 2 to 20 in the No. of thermal ranges option. Note: v8.5 has a new Include Max Range comb option which automatically shows only the maximum thermal stress and the corresponding combination it is occuring at every point including both ambient to all hot cases and all the thermal ranges. This is very useful to quickly find the maximum thermal stress and not have review and print all the ambient to hot and thermal range cases.

Question 102:

Where can I find a sample for a pressure balanced expansion joint?

Answer: Go to Help/Contents/Modeling Approaches/Modeling Approaches/Flexible Joints/Pressure Balanced Expansion Joints.

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Question 103:

How does AutoPIPE decide the allowable stresses on pipes?

Answer: Material allowable stresses are per code. The default values for weld efficiency factors are 1, but these values can be adjusted by going to Insert/Xtra Data/User Weld Efficiency Factors and inputting a lower value when warranted.

Question 104:

How do you know if the axial forces on a flange are in compression, simply by looking at the forces and moments report?

Answer: Go to Tools/Model Options/Results and set Force (Global/Local) to L for local. That will set X as axial to the pipe regardless of its global orientation. Now if you examine your Forces_Moments and Flange Reports, you will see that a negative value will show a tensile force. Also see questions 67.

Back to Index

Question 105:

For Hanger Selection what is considered for spring sizing, cold setting or hot setting?

Answer: The current default hanger selection method uses hot setting or hot load design. There is no automatic option at this time to use cold setting or cold load design.

To perform a cold load design:

Method A

Tools/Model Options/General , add one more temperature case for the model and define at ambient temperature.
Set rigid displacement critera = 0 (so springs are automatically selected even though no thermal displacement)
Run the hanger selection with variation = 0.25 at the new ambient temperature case only.
Springs are all designed now at cold load, change number of temperature cases in Tools/Model Options/General to the original number before step 1 or ignore analyzing this thermal case.

Method B

Set rigid displacement critera = 100"
Run hanger selection with variation = 0.25
Save hanger report
Re-run hanger selection with rigid displacement critera = 0.1"
Edit all hangers and replace the cold load value by the V-stop reaction found in step 3.

Method A is simpler to execute but all springs selected are the stiffest lowest range hence if design load variation is low e.g. 10% then the spring rates for many springs will need to be updated.

Method B requires all cold loads to be updated manually on all springs. The load variation on all springs also needs to be checked and some spring rates may need to be changed.

Now run a static analysis and confirm vertical displacement = 0 under GR at each spring hanger point.
Also recalculate the load variation ratio as [(GR+T1)-GR]/GR = T1/GR
Confirm that both hot and cold reactions can be satisfied by the selected hanger

Advantages of cold load design:

Hanger stops are easier to remove
GR displacement small
Spring loads can be adjusted before system is brought up to temperature
Some consider that cold load approach yields a more dependable design
In some system configurations, operating loads on connected equipment are lower. A typical configuration resulting in this load reduction is one where a hot vertical riser, anchored at the bottom, turns horizontally into a nozzle connection.

Disadvantages of cold load design:

In some systems, in the hot condition the loads on rotating equipment may be increased by a value proportional to spring rate times the travel.
Most installations are done on a hot load design basis since the piping system is operating in the hot condition for most of its project lifecycle.

Question 106:

What is Weightless or As-built when considering gapped supports?

Answer: Gaps may be specified to be set either As- built (weighted) or weightless. If a gap is As- built, it is assumed to be open (i.e. no support) for the gravity load case, then it is set to the specified gap AFTER the gravity load is applied. The stop will then engage only if the pipe displacement due to thermal expansion or any other loads exceeds the gap. In effect, a support with an As- built gap moves with the pipe for gravity load, then remains stationary for thermal and other loads. On the other hand, if the gap is specified in the weightless condition, the gap can change when the gravity load is applied, and the stop may engage. There is one important exception. If a value of zero is specified for any gap, it is always assumed that this zero gap is of the weightless type (i.e., the corresponding stop may engage under gravity load). This is done because we have found that users will generally assume that a zero-gap support acts in this way. If a gap is required to be zero and to be set in the As- built condition (i.e. just closed under gravity load, with zero support load) specify a small, nonzero value (e.g., 0.002 inches).

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Question 107:

In the output report why does the Results Summary reflect two different Occasional Cases?

Answer: The first summary lists the Maximum Occasional Stress and the second lists the Maximum Occasional Stress Ratio. These are very often the same but not always Max Ratio=Stress/Allowable Stress.

Question 108:

Why does the code compliance report show an SIF = 1 for the Sustained Case and 1.3 for all other cases?

Answer: See tools/Model Options/ Results/Set Sustained SIF to 1. This field is only active for the B31.1-1967, B31.3, B31.4, B31.8, DNV, SNCT, CAN-Z662, and KHK level1 codes (it is closed for all others). These codes define stress intensification factors (SIF's) for the expansion stress category only. This option has been provided since no guidelines are presented for the sustained and occasional stress categories. If disabled, AutoPIPE will apply the expansion category SIF's to all other stress categories. When it is enabled, an SIF of 1.00 is used for the sustained category at all points except bends, and the expansion category SIF's are applied to the occasional category. By default this field is disabled for all applicable codes except B31.1-1967.

Back to Index

Question 109:

If a user hasn't saved his model in a while (old bak file) and lost his model by accident, can he use his U0x file and change it to a dat?

Answer: U01, U02 etc up to U99 are actually DAT files. Rename any of the U0x files to DAT and you can retrieve the latest model.

Question 110:

Does AutoPIPE display "Von Mises" as well as "Tresca" stresses on the output report?

Answer: Yes, select Tools>Model Options>Results>Total Stresses (Oct/Max). 'O' represents the maximum octahedral shear (Von Mises) stress, and M represents Max Shear Stress (where Max Shear Stress = Tresca stress/2).

Create 2 output reports in order to display the stresses in the General Stress Calculation section or uncheck the "Overwrite output file" option on the Tools>Model Options>Results dialog.

Also, these stresses could be displayed as a Code Combination, select Help>Contents>Command Reference>User-Defined Code Combinations Category>For all code options …

Back to Index

Question 111:

How do you set up WinNOZL to work with AutoPIPE?

Answer: Install WinNOZL to the default installation directory. Move the entire WinNOZL folder/directory to become a subfolder/directory of AutoPIPE, i.e. C:\Program Files\Bentley\AutoPIPE\WinNOZL. Update any desktop icons and Start>Program folder icons as necessary.

Back to Index

Question 112

On the support output report, the GR's load is not equal to the spring Preload. Why?

Answer: The output report GR reaction is calculated and may not be the same as the design Preload. The Preload (cold load) is extracted from the Hanger analysis report. Using the calculated hot load and the travel distance from the design operating case, the cold load is extracted from the spring manufacturers tables.

Back to Index

Question 113:

How do you model Cryogenic piping?

Companies like Air Products and York Refrigerant use B31.3 for all their refrigerant or cryogenic piping using AutoPIPE. It is not necessary to use B31.5

Please follow the suggested steps below:

B31.3 code compliance case to figure 323.2.2B to avoid Impact Testing for carbon steels.

Combined longitudinal stress due to pressure, dead weight, and displacement strain (stress intensification factors are not included in this calculation) divided by S, at the design minimum temperature. In calculating longitudinal stress, the forces and moments in the piping system shall be calculated using nominal dimensions and the stresses calculated using section properties based on the nominal dimensions less corrosion, erosion and mechanical allowances.

S = nominal design stress at low temperature

AutoPIPE Modeling:

Create a model with one(1) T1, P1 case, with low temp and pressure, so the sustained case (SUS) and (LONG) are based on correct pressure.

Analyze with GR, T1, pressure analysis = ON

Create a user defined code combination as follows:

method = abs sum
category = occasional/li>
combination = (LONG) + GR + cold to T1(s) + P1
The automatic Allowable = K. SH (i.e. S at low temp)
Set the K factor = 1.0 under tools/ code combinations/ occasional load factor.
This combination does add GR, and P1 at the moment level (abs sum) before calculating its stress, which is reasonably conservative, i.e. no moment cancellation in summing the load cases. Less conservative method is to use SUM combination method. Also adding thermal stress separately is conservative.
Select all Tees and Bends and Insert>Xtra Data>User SIF = 1.0 (both in-plane and out-plane).
Tools>Model Options>Results, "Use Nominal Thickness" = unchecked

The calculated stress ratio can be used to evaluate the temperature reduction below the minimum design metal temperature for carbon steel to clause 323.2.2d(1) and Fig 323.2.2B.

Back to Index

Question 114:

My AutoPIPE application runs slowly on my computer, what can I do?

One or more of the following suggestions should help a slow computer using AutoPIPE:

Does the computer meet the minimum requirements? See Help>Contents>Bentley AutoPIPE>Getting Started>Installation and Authorization>Installation>System Requirements.
Change hardware acceleration inside AutoPIPE, View>Settings, uncheck Enable hardware acceleration.
In AutoPIPE, View>Level of Detail, check the option to switch to line mode (and may be also try 3 other options).
Change computer display properties: Control Panel>Disply>Settings tab>Advanced button>Troubleshoot tab, select a lower hardware acceleration. This may be an iterative process.
Control Panel>Display>Appearance?>Effects, the 'Use transition effects for menus and tool tips' option should be unchecked.
Update computer's OPENGL display drivers.
Check to verify that model size has a limitation of < 10,000 points: Tools>Model Input Listing>Extended Components>Number of Points in the System.
Also, you may want to consider defragmenting your hard drive. This can be done (in XP) by going to Programs/Accessories/System Tools/Disk Defragmenter. If your hard drive is very fragmented, the program has to write data in a lot of different locations, and it slows down considerably.
If that does not work, suggest updating the video card, increasing the systems memory, and/or updating the CPU.
Check out a license from the Select Server and unplug the network/internet connection. Reboot the system and start AutoPIPE.

If none of these suggestions have helped, please submit a help desk request to support@bentley.com. Please include the computer's system information. Start>Programs>Accessories>System Tools>System Information. After the program has been opened, select File>Export, then save the file and send a copy for inspection.

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External Links

Bentley Technical Support KnowledgeBase

Bentley LEARN Server

Comments or Corrections?

Bentley's Technical Support Group requests that you please confine any comments you have on this Wiki entry to this "Comments or Corrections?" section. THANK YOU!

Where the bend near point is the start of the bend and the Far point is the end of the bend.

Question 30: Why are spring or rigid hangers on vertical legs showing large reaction loads in the Hydrotest (Hy) case compared to the Gravity (Gr) case?

analyze for gravity;
analyze for gravity plus thermal; then
subtract Step 1 from Step 2 to get thermal.

If analyses are performed for load increments, the steps are:

analyze for gravity; then
analyze for thermal, specifying gravity as the initial state.

AutoPIPE uses the second of these procedures. Thus, to obtain the results for gravity plus thermal, a load combination must be defined in using the commands in the Result menu.

↧

Export Error - Method Not Found

July 23, 2013, 1:09 pm

≫ Next: RAM Structural System Revit Link

≪ Previous: AutoPIPE [FAQ]

Revision 3 posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:09:07 PM

Export Error - Method Not Found

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	AppliesTo

	Product(s):	RAMRevitLink
	Version(s):	ALL
	Environment:	N/A
	Area:	Import/Export
	Subarea:
	OriginalAuthor:	SteveCrabtree,BentleyTechnicalSupportGroup

Method Not Found Error Message TN

If you get the Method not found error as shown below you probably have an extra RAM-Revit Link file or files where they do not belong. The first place to look is in the Autodesk Revit Structure 2010 > Program directory for the Interop.RAMDATAACCESSLib.dll file. If found there delete it. If you continue to get the error run a search of your computer for the Interop.RAMDATAACCESSLib.dll file. If you find it anywhere besides the RAM Structural System\Prog\RAMRevitLink\x86 (or x64)\"Your Revit Structure Version Number", delete it.

↧

RAM Structural System Revit Link

July 23, 2013, 1:10 pm

≫ Next: Mapping RAM "Other" Material TN

≪ Previous: Export Error - Method Not Found

Current Revision posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:10:36 PM

RAM Structural System Revit Link

BIM,RAMStructuralSystem,Revit,export,import,RAM-RevitLink

The RAM Structural System offers true interoperability with the Revit^© Structure Link, part of Bentley's iWare Apps for Interoperability. Bi-directional integration between the RAM Structural System (RSS) and Autodesk® Revit® Structure enables you to analyze and design buildings within the RSS environment and subsequently use Revit Structure for multi-discipline collaboration as well as documentation.

Latest News

An updated and enhance version of the RAM - Revit Link, v5.0, is now available. This version includes some powerful enhancements, error corrections making it more robust and reliable, and adds compatibility with Revit 2013 and Revit Ultimate 2013.
Best practices on interoperability between the RAM Structural System and Autodesk Revit Structure were discussed in our free one-hour eSeminar titled "Latest Developements in the RAM Structural System - Revit link". If you missed it, a recording of the eSeminar is now available on the Bentley website. Additionally, you can read the Question and Answers from our recent [[RAM - Revit Link v4 eSeminar]].
You may also be interested in using the ISM Plug-in for Revit, which allows expanded features such as data exchange with a wide variety of structural analysis, design, drafting, and detailing programs as well as revision history. Revit versions 2010 and 2011-both 32-bit and 64-bit, are supported. Bentley's Structural Synchronizer (free download) is also required. You can download both these applications from Bentley's iWare Apps page.

Download

Get the RAM Structural System Revit Link

Just released...v05.00.00 of the RAM Structural - Revit Link. Download RAM-Revit Link from Bentley's iWare Apps page (free SELECT account required). Compatible with Revit 2013 and Revit Ultimate 2013, as well as earlier versions, Revit 2010 through Revit 2012. Supports both 32bit and a 64bit versions of Revit.

Release Notes

RAM Revt Link Release Notes are also available with version history.

Disclaimer

The software and related documentation, including this documentation, are protected by both United States copyright law and international treaty provisions. Any unauthorized copying or reproduction is strictly prohibited and subject to civil and criminal penalties. Please refer to the License Agreement for authorization to make a backup copy of the software. You may not sell this software or documentation or give copies of them away to anyone else.

Except as expressly warranted in the License Agreement, RAM International disclaims all warranties, expressed or implied, including but not limited to implied warranties of merchantability and fitness for a particular purpose, with respect to the software, the accompanying written materials, and any accompanying hardware. All results should be verified to the user's satisfaction. The contents of these written materials may include technical inaccuracies or typographical errors and may be revised without prior notice.

RAM Revit Link User Guide

Introduction
Starting a Model in RAM Structural System
Starting a Model in Revit Structure

RAM Revit Link Tutorial

Introduction
Revit Structure
Exporting to RAM Structural System
Inside RAM Structural System
Importing Changes back to Revit Structure
Re-exporting to RAM Model

RAM Revit Link Best Practices

Introduction
Starting in Revit Structure
Start Modeling in RAM Structural System

Recroded Seminar on the RAM - Revit Link v4.0 (2012-02-28) and corresponding Q&A log

Recorded Seminar on the RAM - Revit Link v3.0

Recorded Seminar on the RAM - Revit Link v2.0 (2008-02-13) and corresonding Q&A log

RAM-Revit Link Tips And Tricks

These tips and tricks represent solutions to common issues users have asked us about.

If you have questions, please ask them at the Analysis & Design Forum here on Be Communities. Alternately, you may also send them to Bentley Technical Support. If you have determined a solution to a RAM Revit Link problem you'd like to share, please post them on this wiki page.

Note: You must be a registered user and logged in to add information on this page.

[[Can't Make Joist Error]]
[[Change Reaction Mark]]
[[Editing Revit Joist Families]]
[[Enhanced Deck Mapping]]
[[Export Error - Method Not Found]]
[[Mapping Floor Types]]
[[Mapping RAM "Other" Material TN]]
[[Modeling a Sloping Deck]]
[[RAM Modeling - Use One Floor Type Per Level]]
[[Remove Camber Inch Mark Symbol]]
[[Reset RSS Origin]]
[[Revit Link Coordinate Mapping]]
[[Stud Count Bracket Options]]

Autodesk and Revit are registered trademarks of Autodesk, Inc. This website is independent of Autodesk, Inc.

↧

Mapping RAM "Other" Material TN

July 23, 2013, 1:15 pm

≫ Next: Mapping Floor Types TN

≪ Previous: RAM Structural System Revit Link

Revision 4 posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:15:22 PM

Mapping RAM "Other" Material TN

RAM, RAM Structural System, Revit, howto, export, import, SELECTsupport, RAM-Revit Link,Import/Export,RAMRevit Link


	AppliesTo

	Product(s):	RAMRevitLink
	Version(s):	ALL
	Environment:	N/A
	Area:	Import/Export
	Subarea:
	OriginalAuthor:	SteveCrabtree,BentleyTechnicalSupportGroup

Mapping RAM “Other” Material Elements

“Other” material elements can now be imported into Revit with the RAM Revit Link. To control what gets created on import into Revit you need to make a few modifications to the mapping and the element properties of what you want imported. If you do not add mapping for the “Other” material elements they will be imported into the Rectangular Concrete Beam family.

In this example we are going to add Glulam-Southern Pine to the mapping.

Mapping

1. Open the mapping editor from inside either the Revit Link Import or Export dialog

2. Select the Concrete tab and pick the add New Item button

3. Set the dialog to match the properties below and browse and select the Glulam family.

4. Click OK, save the mapping and exit out of the Importer/Exporter

Edit the Family

Next we will load the Glulam family into the model and modify the material properties.

1. On the Revit Insert tab select Load Family.

2. Navigate to the Glulam family and load it into the model (Select any size you want from the table. It is not necessary to pick a size that exists in the RAM model. The Revit Link will generate the necessary sizes when the model is imported.)

3. Right click on the Glulam family and select Edit

4. In the family Editor pick Family Type icon

5. In Materials and Finishes pick the browse button in the Value field

6. Select the Physical tab and set the Material Type to Generic

7. Click OK in each dialog to close them.

8. Save the family and load it into the project. (You must have read/write privileges to the family in order to save.)

9. If you are asked to overwrite the existing pick the second option to overwrite the existing and parameters.

Now when you import “Other” material elements from RAM they will be placed in the correct Revit family.

↧

Mapping Floor Types TN

July 23, 2013, 1:16 pm

≫ Next: Mapping Floor Types TN

≪ Previous: Mapping RAM "Other" Material TN

Revision 4 posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:16:11 PM

Mapping Floor Types TN

BIM, RAM Structural System, Revit, export, import, SELECTsupport, RAM-Revit Link,Import/Export,RAMRevit Link


	AppliesTo

	Product(s):	RAMRevitLink
	Version(s):	ALL
	Environment:	N/A
	Area:	Import/Export
	Subarea:
	OriginalAuthor:	SteveCrabtree,BentleyTechnicalSupportGroup

Mapping the floor types TN (Also see the Enhanced Deck Mapping article)

Now that you have the new floor types necessary in the Revit model you will need to map these to the RAM model deck properties.

1. Open the RAM Importer dialog.

2. In the Mappings box of the Importer click the Edit button.

3. In the Mappings Editor select the Deck tab.

4. Select the appropriate floor type from the drop down.

5. Click the Plus sign to add mapping for your floor type.

6. In the Add New Item dialog select the floor type you added to the Revit family from the drop down.

7. Enter the exact deck type name used in the RAM model in the Label text field.

8. Enter only those design parameters used in the RAM model in the appropriate fields. These also must be exactly the same as in RAM.

9. Click the Add button.

10. Repeat for any additional mappings needed.

11. Save the mapping file and close.

12. Back in the Importer import the model as normal.

You should now be able to import your deck/slabs from RAM. If you still get mapping errors in the log file go back and recheck the mapping properties in the Mappings Editor. If you find that everything matches RAM correctly try deleting any mapping that does not apply to the current model and re-import.

↧

Mapping Floor Types TN

July 23, 2013, 1:16 pm

≫ Next: Editing Revit Joist Families TN

≪ Previous: Mapping Floor Types TN

Current Revision posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:16:34 PM

Mapping Floor Types TN

BIM,RAMStructuralSystem,Revit,export,import,SELECTsupport,RAM-RevitLink,Import/Export,RAMRevitLink


Applies To

Product(s):	RAM Revit Link
Version(s):	ALL
Environment:	N/A
Area:	Import/Export
Subarea:
Original Author:	SteveCrabtree,	Bentley Technical Support Group

Mapping the floor types TN (Also see the Enhanced Deck Mapping article)

Now that you have the new floor types necessary in the Revit model you will need to map these to the RAM model deck properties.

1. Open the RAM Importer dialog.

2. In the Mappings box of the Importer click the Edit button.

3. In the Mappings Editor select the Deck tab.

4. Select the appropriate floor type from the drop down.

5. Click the Plus sign to add mapping for your floor type.

6. In the Add New Item dialog select the floor type you added to the Revit family from the drop down.

7. Enter the exact deck type name used in the RAM model in the Label text field.

8. Enter only those design parameters used in the RAM model in the appropriate fields. These also must be exactly the same as in RAM.

9. Click the Add button.

10. Repeat for any additional mappings needed.

11. Save the mapping file and close.

12. Back in the Importer import the model as normal.

↧

Editing Revit Joist Families TN

July 23, 2013, 1:17 pm

≫ Next: Enhanced Deck Mapping TN

≪ Previous: Mapping Floor Types TN

Current Revision posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:17:15 PM

Editing Revit Joist Families TN

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Applies To

Product(s):	RAM Revit Link
Version(s):	ALL
Environment:	N/A
Area:	Import/Export
Subarea:
Original Author:	SteveCrabtree,	Bentley Technical Support Group

Editing Revit Joist Families TN

This will show you how to add joist designations that are applied to designed joist in RAM Structural System to the Revit Joist families. This includes SP, CS and joist girders. The joists that will be created are only to represent the joists imported from RAM and they do not necessarily have the correct configuration of the real joist.

The first thing you need to do is to navigate to your Revit Joist family. The default location in Windows XP would be:

C:\Documents and Settings\All Users\Application Data\Autodesk\RST 2011\Content\Imperial Library\Structural\Framing\Steel

There you will find 2 K series joist families. Rod web and angle web joists. Associated with each of the Revit “*.rvt” files is a text file with the same name. Right click the text file and select Properties. On the General tab page uncheck the Read Only checkbox and click Apply. Then close the properties dialog. Make a copy of the text file and rename it so that you do not lose the original file. Open the text file with Notepad. Scroll down until you find a joist the same size as the one you want to add.

Copy the line for the existing joist and paste it below the original. Edit the name to match the RAM designed joist name. (SP, CS, etc.)

You can use this same method you add joist girders with designations such as: 28VG5N9.1K. Remember these are only to represent the girders in the RAM model and do not necessarily match the actual girder layout.

↧

Enhanced Deck Mapping TN

July 23, 2013, 1:17 pm

≫ Next: Export Error - Method Not Found

≪ Previous: Editing Revit Joist Families TN

Current Revision posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:17:38 PM

Enhanced Deck Mapping TN

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Applies To

Product(s):	RAM Revit Link
Version(s):	ALL
Environment:	N/A
Area:	Import/Export
Subarea:
Original Author:	SteveCrabtree,	Bentley Technical Support Group

A new menu item has been added under Edit menu in the mapping editor to ease the process of mapping the slab and deck when importing your RAM model.

By clicking the Map Slabs/Decks From RSS File, deck property information is read from the RAM model and the following dialog box is displayed:

“Revit Type Name” list box contains all the type names defined in current Revit model and “RAM” list box contains decks defined in RAM model. By clicking on “Add” button a new mapping is created. The user may click on “Deck Properties Information” button for more details. Depending on the selected deck (and Units used in the RSS model) a dialog box will be shown similar to the following:

SI units for decks/slabs mappings:

When editing mapping that uses Metric units the user can use two representation modes: Metric and SI. For example, here’s the same mapping, but on the left side it is represented in Metric, while on the right side it is in SI:

Also see the Deck Mapping and Mapping Floor Types tech notes for additional information.

↧

Export Error - Method Not Found

July 23, 2013, 1:18 pm

≫ Next: Mapping RAM "Other" Material TN

≪ Previous: Enhanced Deck Mapping TN

Current Revision posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:18:02 PM

Export Error - Method Not Found

BIM,RAMStructuralSystem,Revit,export,import,SELECTsupport,RAM-RevitLink,ErrorMessage,Import/Export,RAMRevitLink


Applies To

Product(s):	RAM Revit Link
Version(s):	ALL
Environment:	N/A
Area:	Import/Export
Subarea:
Original Author:	SteveCrabtree,	Bentley Technical Support Group

Method Not Found Error Message TN

↧

Mapping RAM "Other" Material TN

July 23, 2013, 1:18 pm

≫ Next: Modeling a Sloping Deck TN

≪ Previous: Export Error - Method Not Found

Current Revision posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:18:35 PM

Mapping RAM "Other" Material TN

RAM,RAMStructuralSystem,Revit,howto,export,import,SELECTsupport,RAM-RevitLink,Import/Export,RAMRevitLink


Applies To

Product(s):	RAM Revit Link
Version(s):	ALL
Environment:	N/A
Area:	Import/Export
Subarea:
Original Author:	SteveCrabtree,	Bentley Technical Support Group

Mapping RAM “Other” Material Elements

In this example we are going to add Glulam-Southern Pine to the mapping.

Mapping

1. Open the mapping editor from inside either the Revit Link Import or Export dialog

2. Select the Concrete tab and pick the add New Item button

3. Set the dialog to match the properties below and browse and select the Glulam family.

4. Click OK, save the mapping and exit out of the Importer/Exporter

Edit the Family

Next we will load the Glulam family into the model and modify the material properties.

1. On the Revit Insert tab select Load Family.

3. Right click on the Glulam family and select Edit

4. In the family Editor pick Family Type icon

5. In Materials and Finishes pick the browse button in the Value field

6. Select the Physical tab and set the Material Type to Generic

7. Click OK in each dialog to close them.

8. Save the family and load it into the project. (You must have read/write privileges to the family in order to save.)

9. If you are asked to overwrite the existing pick the second option to overwrite the existing and parameters.

Now when you import “Other” material elements from RAM they will be placed in the correct Revit family.

↧

Modeling a Sloping Deck TN

July 23, 2013, 1:19 pm

≫ Next: RAM - Revit Link v4 eSeminar

≪ Previous: Mapping RAM "Other" Material TN

Current Revision posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:19:56 PM

Modeling a Sloping Deck TN

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	AppliesTo

	Product(s):	RAMRevitLink
	Version(s):	ALL
	Environment:	N/A
	Area:	Import/Export
	Subarea:
	OriginalAuthor:	BentleyTechnicalSupportGroup

Modeling Sloping Deck TN

Open the Roof plan view.
Select the Home tab and then the Floor icon.

Once you have selected the Floor icon the Draw panel will be visible. Pick the Slope Arrow icon.

Pick two endpoints on a beam in the slope of the roof.

Right click on the Slope Arrow and select Element Properties.

In the properties dialog set the Height Offset at Tail and Head to the desired elevations.

On the draw panel select the Add Sketch Lines icon with the picture of the beam and deck. Pick each of the perimeter beams that outline the area of the deck. (You could also pick one of the other draw tools to define the deck area.)

Click the Finish Floor button to complete the command.

↧

RAM - Revit Link v4 eSeminar

July 23, 2013, 1:22 pm

≫ Next: RAM Modeling - Use One Floor Type Per Level TN

≪ Previous: Modeling a Sloping Deck TN

Current Revision posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:22:56 PM

RAM - Revit Link v4 eSeminar

RAM-RevitLink


	AppliesTo

	Product(s):	RAMRevitLink
	Version(s):	ALL
	Environment:	N/A
	Area:	Import/Export
	Subarea:
	OriginalAuthor:	BentleyTechnicalSupportGroup

Q&AandLinktoSeminarRecording

This eSeminar was orginally presented on 28 February, 2012. You can view the recording online at our Be Connected site.

The following are the product-related questions and corresponding answers from the eSeminar presented on 28th February 2012.

Q: Can this Revit link enable users to bring in "multiple Ram Models" into the same "single" Revit Model?
A: No. Only one RAM Structural System model can be imported into a Revit file. However, you can use linking between multiple Revit files to associate various structures in a single Revit project.
Q: What is the Full form of ISM?
A: Bentley's Integrated Structural Modeling technology utilizes the MicroStation .dgn file format to create a repository of structural data common among various structural programs. The structural data is a subset of the complete BIM and any one ISM Enabled client application can utilize a subset of the structural data from the ISM repository. Further, this provides design history which allows rolling back to previous version as well as merging versions of repository content. The free Structural Synchronizer program is used to manage ISM repositories and sync structural data with client applications. A free ISM Revit plug-in is also available to exchange structural data with a Revit project.
Q: What are the possibilities with using RAM elements and Revit structure?
A: RAM Elements is an ISM Enabled program and is fully compliant with the ISM v2.1 standard. You can exchange structural data with RAM Elements through the ISM Revit plug-in.
Q: is it true you can only set the "offset" coordinates once? Otherwise you lose the RAM/Revit link?
(Note: There were several questions on this same topic.)
A: When you set coordinates on the Offset tab of the settings dialog, that value becomes a read-only property of the RAM model. We do have a spreadsheet that can be used to create a new RAM model at a zero origin in RAM. If there have been loads or foundations added to the model, they are lost when you create the new model.
Q: When I am using the RAM Revit Link it appears that the link reads the reference level on a beam, and not the analytical model assignment, is there any way to make the RAM Revit Link read the analytical model in Revit 2012?
A: The link is only going to transfer data from the analytical model. It’s likely that there have been changes made which have unintended consequences in the analytical model. You should use the analytical adjust tools to make modifications, similar to those made I the demo for the shortened column.
Q: Why isn't the slab on top of the beams? Was this intentional?
A: Yes, this was intentional, but will be enhanced in future versions. During portions of the live demo, the display of the Revit floor was toggled off in the {3D} view of the physical model.
Q: You should model a cantilever at one of the joists too, not just at columns.
A: Cantilevers on beams that are supported by girders are handled by the link, but not demonstrated in this eSeminar. Cantilevers for joists and concrete beams are not supported.
Q: What about when the actual column splice is 4 feet above the floor?
(Note: There were several questions on this same topic.)
A: You can use the same column shorten/extend method in the physical model as shown in the demo for extending a beam cantilever. Just be certain to adjust the analytical model so it actually changes sections at the floor level, in the plane collinear with the floor framing analytical members.
Q: Can you specify the column splice location in RAM?
A: No. The splice assignment in RAM Steel Column is used to indicate that the program may assign a different section size on the adjacent story above. The exact splice location is not specified with RAM because it isn't used in RAM. The link will respect a story level that is set in RAM but it will be at the story level when imported into Revit.
Q: When exporting a Revit model into RAM, how does RAM treat members that it can't analyze, i.e. curved members, etc.?
A: The link only passes data which the RAM Structural System can analyze. Any such members will not be exported to RAM via the link.
Q: How well does custom/other framing translate between RAM and Revit, such as LVL /wood framing?
A: The “other” material now transfers to RAM via the link. You will probably need to specify the material as “generic” in Revit, first.
Q: How often are the RAM - Revit links updated?
A: Patch updates are issued as needed, but relatively often (roughly monthly). Larger, feature updates are less often.
Q: Is there an efficient way to model open web steel joists so they show up with the seats in the correct location above the supporting member in Revit, but no have to make substantial modifications to your analytical model so that Ram SS will function correctly?
A: It is best to specify the joist seat offsets when a joist is added to the Revit model. Otherwise, joist offsets are subject to the same analytical/physical modeling differences in Revit as demonstrated with column end offsets.
Q: In an integrated practice, is it better to start a model in Revit or RAM?
A: We see users who start in either, though it appears to be most common to start in Revit (perhaps as models are received from clients).
Q: Can you expand on the differences between the RAM-Revit link versus the ISM-Revit link?
A: The Revit link uses the analytical model and ISM uses the physical model to exchange the location of the elements. Not all material is available in the ISM plug-in yet and some elements will be assigned a generic ISM material. Not all deck types are available and one of the ones that is available needs to be used to export decks from RAM. RAM does not support importing decks in this version. It will import decks in the next release. A significant update to the RAM-ISM-Revit link is currently being developed and will be released this summer.
Q: We are experiencing trouble with exporting Revit Braces to RAM. Any tips for successfully modeling those in Revit and get them to RAM?
A: Yes. You can read some tips in our [[RAM Revit Link Best Practices]] wiki topic. However, you should make sure that the reference levels are set to the top framing level for the brace. Also, make sure to review the analytical model in Revit in order to ensure that the braces are appropriately connected to the framing members and/or columns.
Q: We have practiced with a multi-story building and slab on grade, of which we exported from Revit to RAM Steel. After working in RAM Steel and importing back to Revit, the ground floor slab on grade information is lost.
A: This is a limitation of the Revit API, which does not allow for the import of continuous or mat foundations.
Q: If you start with Revit, send to RAM and bringing back to Revit, how do you avoid duplication of levels?
A: Make sure that the Import as New Model option is not set during re-import. This option will result in duplicate levels when importing back into a Revit project.
Q: You modeled the cant. by shortening the column. How would you handle a baseplate that would be added in Revit? How will that impact the RSS model?
A: You can make an analytical model adjustment similar to the column shortening exercise so the analytical column extends to the floor level defined as the base of the column in question.
Q: Can RAM generate a 3D PDF directly (from RAM)?
A: No. However, you can use Structural Synchronizer to create a 3D PDF from any RAM Structural System model by creating (or updating) an ISM repository. Similarly, you can use the ISM Revit link to create a 3D PDF out of your Revit project. The ability to create a 3D PDF directly from RAM is scheduled to be included in V14.05, due out this summer.
Q: How does RAM handle sloped roofs/diaphragms?
A: Sloping floors, roofs, or diaphragms can be modeled in the RAM Structural System by simply using the Modify Elevation tool and then specifying the top-of-column offset (extend or shorten). See also the [[Modeling a Sloping Deck TN]] wiki topic.
Q: What precautions should we use when modeling in Revit for exporting to RAM?
A: Please refer to the Starting in Revit section in our [[RAM Revit Link Best Practices]] wiki topic.
Q: Will Bentley be continually updating this link or is the future the ISM link?
A: This link is going to be updated in the future as needed. We plan to maintain the link so long as it has features which aren’t available though ISM. However, there are likely to be future features of either the RAM Structural System or Revit Structure which will only be possible to exchange through the ISM Revit plug-in.
Q: When you modeled the cant., it appears that you did not model it to follow the curved grid. Can you model the cant. beam to match the grid curve?
A: No. Members in RAM must be linear members. However, the curved grid for this model is solely for column layout. All beams are straight, including the back spans of the two cantilevered beams modeled during this demo.
Q: Does ISM support Revit 2012?
A: Yes. Revit Structure 2012 (both 32- and 64-bit) are supported as of v2.1 of the ISM Revit plug-in, along with Revit Architecture and Revit MEP. Revit Structure 2012 is also supported by the RAM - Revit link.
Q: Typically when we import RAM into Revit, the RAM model elevation is 0'-0" and Revit model is at 100'-0". How do you adjust this elevation?
A: Use the Settings dialog Offset tab to specify the translations (which may be simply zero).
Q: Any timeframe on a future Revit ISM Webinar?
A: We do plan to have some seminars planned in a few months for Integrated Structural Modeling and Revit integration will play a key role in this.
Q: Can the link translate "future" phases of construction for RAM analysis?
A: No. The link does not support Revit phases.
Q: What is the best way to handle vertical offsets (2 1/2" bar joist seats for example) in Revit to RAM? Do we need to establish separate story levels?
A: Like the earlier question this should be setup when they are creating the model and not adjusted later.
Q: Why the TOS elevation coming from Ram into Revit matches the TOC of the slab? We have to manually adjust the TOC of the slab after the import...Any comments on how to handle this issue other that adjust after importing into Revit?
A: This is correct. The slabs do come into Revit with the top of slab at top of steel level. I simply neglected this and didn’t change my settings. You can offset the slab location then uncheck the option to update slabs or they will move back to the top of steel level on subsequent imports. This is because the slabs are handled so differently between RAM and Revit that they are actually deleted and recreated on import.
Q: How does a beam offset from a floor in Revit translated into RAM?
A: Currently, the beam offset must be made in the Revit physical model only and the analytical members remain co-linear. Rigid member offsets — available in the RAM Structural System later in 2012—will be able to accommodate analytical offsets which would result in different structural behavior (torsion, moment, etc.).
Q: When bringing a concrete wall in to Revit from RSS, does it bring the reinforcing along? (Will the reinforcing show up in Revit?)
A: No. The rebar designs are not supported by the RAM – Revit link. Rebar is partially supported using ISM and that will be required to transfer reinforcing designs in future versions.

↧

RAM Modeling - Use One Floor Type Per Level TN

July 23, 2013, 1:24 pm

≫ Next: RAM Revit Link Best Practices

≪ Previous: RAM - Revit Link v4 eSeminar

Current Revision posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:24:28 PM

RAM Modeling - Use One Floor Type Per Level TN

BIM,RAMStructuralSystem,Revit,export,import,RAM-RevitLink


	AppliesTo

	Product(s):	RAMRevitLink
	Version(s):	ALL
	Environment:	N/A
	Area:	Import/Export
	Subarea:
	OriginalAuthor:	BentleyTechnicalSupportGroup

RAM Modeling - Use One Floor Type per Level TN

When building your model in the RAM Modeler you should only use one floor type per story if you are going to import the model into Revit Structure. In Revit elements are independent from each other, so if you want to change something for a group of elements you can select them and then apply changes to the group. In RAM it is enough to change one beam on a floor type and changes then will be reflected on all floors which use that particular floor type, i.e. all corresponding beams on other floors change. But if we change a beam in Revit and we want to update the RAM model from Revit, the Revit Link doesn't really know what to update. In RAM the beam has been generated by a floor type on multiple floors.

↧

RAM Revit Link Best Practices

July 23, 2013, 1:25 pm

≫ Next: RAM Revit Link Meeting QA Log

≪ Previous: RAM Modeling - Use One Floor Type Per Level TN

Current Revision posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:25:56 PM

RAM Revit Link Best Practices

BIM,RAMStructuralSystem,Revit,export,import,RAM-RevitLink


	AppliesTo

	Product(s):	RAMRevitLink
	Version(s):	ALL
	Environment:	N/A
	Area:	Import/Export
	Subarea:
	OriginalAuthor:	BentleyTechnicalSupportGroup

⇑ Up to the RAM Structural System Revit Link

Please read the Disclaimer.

Introduction

The Bentley RAM Revit Link can be used to export Revit Structure models to the RAM Structural System. Or, you can start in RAM Structural System create your model and import it into Revit Structure.

Starting in Revit Structure

When the model is started in Revit Structure there a few things to consider for a successful export to RAM Structural System. The most important thing to remember is not to model something you cannot model in RAM and expect it to successfully export from Revit.

Setting Levels

When modeling your building in Revit Structure, you will need to follow a few best practices to ensure a successful export to RAM Structural System.

Ground Level

The Bentley RAM Revit Link now has coordinate mapping so that you can model structures in Revit below the ground floor. When you export to RAM the lowest level in the RAM model will be at the 0’-0” elevation. (See the Wiki article on Coordinate Mapping)

Levels

Be sure to set the Base Level and Top Level appropriately for columns and the Base Constraint and Top Constraint for walls as shown below. (See Figure 2 below.) The top and bottom levels should always be set to the closest level. You should never offset from a level which crosses another level. If you build the model so that all of the analytical lines are at the deck bearing level your model will export successfully. If you have depressed framing on a level set them members to the deck bearing level and offset them in the Revit Element Properties dialog. If the analytical lines do not intersect in Revit the members will be unsupported in RAM. (See Figure 1 below.)

Figure 1: Analytical lines set to the top of steel level.

Figure 2: Set Base and Top Level to correct reference levels

Vertical Braces

For vertical braces, be sure to set the Reference Level to the top level to which the brace attaches. Otherwise, the braces will not export correctly to RAM Structural System. (See Figure 3)

Figure 3: Vertical Brace Reference Level

Foundations

Add the foundations to the model at the same level as the bottom of the column. (As shown in Figure 4) On export, the link will determine which member a foundation supports and will associate the foundation with the same level as that member in the RAM Structural System.

Figure 4: Footing modeled at same level as supported column

Analytical Checks

It is important to Analytical Model Tools in Revit to detect any modeling errors before exporting to RAM. On the Analyze tab run Consistency Checks and Check Supports. Address any errors reported before exporting.

Element Properties

As you build your Revit model make sure that the elements you add have the properties set correctly. This can prevent having to make changes later.

Analyze As

Revit Structure provides this property for beams, columns, and braces. Braces will always be exported to RAM Structural System as lateral members. To export beams and columns as Lateral members, be sure to set the “Analyze As” flag accordingly. It is a good practice to only export the objects that you want analyzed in RAM Structural System. You can do this by creating a selection set of the objects in Revit. Or, you can set the “Analyze As” option to “Not for analysis”.

Figure 5: Beam with “Analyze As” flag set to Lateral

Cantilevers

For the Revit Link to detect cantilever framing conditions you need to set the check Member Supports in the Structural Settings dialog. (See example below).

Figure 6: Modeling cantilevers for export.

Loads

To ensure that loads are exported to RAM as expected, please note that Revit Structure load nature names are mapped to the RAM Structural System load types as follows:

Revit Load Nature Name	RAM Structural System Load Type
Dead	Dead¹
Live	Live Reducible
Floor²	Live Reducible
Live Reducible²	Live Reducible
Live UnReducible²	Live unreducible
Live Storage²	Live Storage
Wind	not imported
Seismic	Not imported
Snow	Live Roof
Roof Live	Live Roof

¹RAM SS can only handle one dead load case so all Revit Structure dead loads are added together if more than one occurs.

²These are not default load natures but can be added within Revit.

Note: Load nature names, which are editable in Revit Structure, must match exactly as listed above to ensure proper mapping between systems.

Exporting to RAM Structural System

Once the building is modeled in Revit Structure and has been saved, you can export the model to RAM Structural System. On the Add-Ins tab in Revit Structure, select External Tools > Export Model to RAM. This will launch the RAM File Exporter dialog.

Figure 7: RAM File Exporter dialog

Export Options

The default location for the new RAM model is the same directory as the Revit model, and the default name is the same as the Revit model name.

You can optionally export only members that were first selected in Revit Structure. As mentioned earlier you can set up selection sets and pre-select the objects before opening the export dialog. If you do export only selected objects do not use the Perform Deletes options in either the import or export dialogs. This will cause your non-selected elements to be deleted when you update.

Click the Settings button to see additional export options.

Figure 8. Export Settings

To maintain the element shape type when exporting to RAM select Freeze Gravity and Lateral member. You can clear the design once you are in RAM so that it can design the members.

By default, the exporter will launch the new model in RAM Structural System when it is completed. Select None to simply create the RAM model without launching RAM Structural System.

If your Revit model is not modeled at 0, 0, 0 origin select the Offset tab to enter the coordinates. The RAM model will be created at the 0, 0, 0 origin. The offset will be stored in the RAM model and used to update the Revit model correctly. (See the Coordinate Mapping article on the RAM-Revit Link Wiki.)

On the Other tab default option for log messages is to log the minimum number of messages. This option will report any errors on export. For the most information on the export process, select the All option for Log File Messages. The All option is especially useful for diagnosing problems. The log is not automatically saved and you will have to save it if you want a record.

Mapping File

The RAM Structural System link to Revit Structure makes use of a mapping file to map Revit Structure Family files to the corresponding shapes in RAM Structural System. The default mappings should work in most cases. However, if you use custom families in Revit, you may need to modify the mapping file. Click on the Edit button to launch the mapping file dialog.

Figure 9: Dialog to edit mapping of Revit families to RAM shapes

Note that the Revit Link comes with separate Imperial and Metric files. To change the Revit family associated with a RAM Shape, simply double-click on the Revit Family Name and a File Open dialog will appear where you can select a different Revit Family File. (See the Revit Link Wiki page for the Enhanced Deck Mapping article.)

Exporting

Once the export options have been selected and the mapping file is set up correctly, click Export to begin exporting the model to the RAM Structural System.

Start Modeling in RAM Structural System

This section covers what you need to do in RAM Structural System before importing your RAM model into Revit Structure. It assumes familiarity with the RAM Structural System. In order to maximize the benefit of the link with RAM Structural System, there are a few practices we recommend using when modeling in RAM and importing to Revit Structure.

Modeling

There are few modeling restrictions for building your RAM Structural System model for import into Revit Structure. There are a few guidelines to follow and there are some limitations to what you can model in RAM.

Gridlines

Each grid system that you create in your RAM model must have unique grid labels. If not when you import the RAM model duplicate grids labels will be automatically relabeled as they are created. This includes unlabelled grid lines in RAM. Revit considers unlabelled grids to be duplicates and will rename them each time they are imported. This does not apply to construction grids. They are not imported into Revit.

Levels

You should not use level names that are used in your Revit template file that you use when importing the RAM model. If the names are the same you should change them in the new Revit project file before you import.

Columns

Presently when you model columns in RAM they are imported as individual columns that can only extent from one level to the next. Multistory columns cannot be imported into Revit. If you modify the columns in Revit so that they are multistory, they will maintain the multistory length when updating from RAM.

Importing your new RAM Model

You can import your RAM model at any stage of design. All of the gravity and lateral members must have a size assigned or the import will log an error.

Project Template

When importing a new RAM model into Revit, you should always start your new Revit project from a template. Although this adds some levels that you do not need in the model, the link does not work well if the Revit project is started without a template. Your template should include members from each type of family you will be importing from RAM. It does not need to have the exact size loaded into the template but it works best if there is a member of the family loaded. This is especially true for concrete members. If you have both square and rectangular concrete columns in your RAM model you will need to have one size from each of the Revit concrete column families loaded into the template.

Delete Levels

Once the RAM model is imported, the default levels from the project template (Level 1 and Level 2) should be removed from the model, especially if the model is to be re-exported to the RAM model at a later time.

Import Limitations (for importing a new RAM model)

Here is a list of a few limitations for importing your RAM model.

Continuous foundations are not imported. (This is a limitation of the Revit Structure API.)
Pile cap foundations are not imported.
Grid bubbles may not be at the same end of the grid lines as they are in RAM.
Grid lines may only show up on lowest level imported. (The easiest way to get the grid lines visible on all levels is to cut sections across the building perpendicular to the grids. Open the section views and stretch the vertical grids to the top of the building.)
Load combinations are not imported.

What is imported?

Steel beams, columns and braces.
Concrete beams, columns, walls and isolated foundations.
‘Other’ walls. (imported as Generic)
Member end fixity.
Material properties.
Column orientation.
Beam camber (in inches) and stud information.
Maximum beam reactions.
Gravity point, line and surface loads. *

* These items are only imported when importing a new model from RAM, not when updating an existing Revit model.

↧

RAM Revit Link Meeting QA Log

July 23, 2013, 1:27 pm

≫ Next: Remove Camber Inch Mark Symbol TN

≪ Previous: RAM Revit Link Best Practices

Current Revision posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:27:39 PM

RAM Revit Link Meeting QA Log

RAM,RAMStructuralSystem,Revit


	AppliesTo

	Product(s):	RAMRevitLink
	Version(s):	ALL
	Environment:	N/A
	Area:	Import/Export
	Subarea:
	OriginalAuthor:	BentleyTechnicalSupportGroup

Though this eSeminar covers an older version of the RAM - Revit link, there are plenty of great tips and best practices which our users have found useful. A recording is available at the Bentley website.

Questions and Answers - Integration of the RAM Structural System and Revit Structure LIVE eSeminar

(2/13/2008 answers updated 11/19/2011) If you have any further questions, please contact us!

1. When I select "Import" as a new model, the Map screen doesn't come up

Answer: To see the mapping file click the Edit button in the Revit Link Importer dialog.

2. Do joists take longer to import?

Answer: Yes because all of the individual elements of the joist must be drawn when they are imported from RAM.

3. Where is the mappings file stored? Can it be stored in a network location?

Answer: You can relocate the mapping file. In Windows XP the files are located in the RAM Structural System > Prog directory and the file names are ImperialMapping.map and MetricMapping.map.

4. When importing a RAM model into REVIT, the base elevation is 0"-0". We usually set the first floor to elevation 100'-0". Is there a way to work around this without having basements that are 100 feet high?

Answer: There is a new feature in the Revit Link that allows you to define an offset for the Revit model. When the model is exported to RAM it is created at the 0,0,0 origin. When imported back from RAM the offset is used to locate the model in Revit.

5. Are you recommending that the model be started in RAM rather than Revit?

Answer: You can start in either. It is very easy to first create the structural model in RAM and then import to Revit - especially for the Engineer

6. Can you show the end reactions for the beams generated in RAM on Plan in REVIT?

Answer: Yes you can. There are standard Revit tags for the beams to include this information. Use the Beam Annotation tool in Revit to set up the tags.

Our primary concern is if RAM and Risa work well with Revit. Also Ram and Risa's other software tools...Risa Floor, RAM Foundation etc. We need to choose one or the other, or should we buy Robobat?

Answer: We are demonstrating RAM and Revit which works very well together and has for years.

7. How does one deal with the architectural unit to decimal feet when going from Revit to RAM? Rounding errors?

Answer: You can create your Revit Structure model using Decimal feet if you chose to do so during integration with RAM

8. Do you know how to get the end reactions to be appropriately placed at the beam ends automatically? We had to move the reactions the beam ends manually after import.

Answer: There is a setting in the Beam Annotation tool that lets you adjust the tag reaction tag location.

9. Can the model be started in RAM Elements?

Answer: You can use ISM (Integrated Structural Model) tool in RAM Elements to create a repository which can be imported into Revit.

10. Has any solution for analyzing joist when the horizontal projection is set to top of joist, which is 2.5” above the beam because of the joist seat been worked on?

Answer: All of your analytical projections for the framing should be on the same plane for analysis regardless of the physical model.

11. On this model, are there any cantilever conditions where the beam actually extends over the top of a column to create the cantilever? Our engineers typically have to model that with 2 beams in RAM and this creates an issue when we bring it into Revit. Let me know if this doesn't make sense to you.

Answer: The cantilevers have to be modeled in two pieces in Revit to export correctly to RAM.

12. There seem to be lots of errors when you start a model in Revit and then export to RAM. I understand it would be preferable to start in RAM, but that's not feasible in our office. How do we avoid so many errors when we travel from Revit to RAM?

Answer: My suggestion would be to first use some of the tools in Revit Structure to verify the analytical model before you export to RAM. If you clean up the errors in Revit you will have minimal errors in the RAM model.

13. Do you have to have Ram installed on the same system as Revit in order to import and export?

Answer: Yes you do.

14. Do you need to update to RAM V11.3 or can you use V11.2?

Answer: You can still use 11.2.

15. Any idea when continuous footings will be available in Revit between columns instead of just under walls?

Answer: You can create slab foundations already that will do the same. Just sketch the condition you need. Continuous foundations cannot be imported from RAM Structural System because they are not supported in Revit.

16. Do the vertical brace sizes update in the Revit model with the new link? Our experience with the old link did not allow us to update these elements.

Answer: Brace sizes will now update.

17. What would then be the step to import the file into advance for connection design? Will you need to ship back to Ram SS then dxf to Ram Elements?

Answer: Yes, you would need to go through RAM Structural System to get to RAM Elements. There is no round tripping.

18. We have had problems importing joists from RAM into Revit. Is there a solution for this?

Answer: This is fixed in the latest version and feel free to contact Steve Crabtree if you still have problems.

19. How do we do base plates in the column schedule

Answer: You can add some rows in the columns schedule to add this information. Also, improvements are being made to the graphical column schedule in Revit Structure

20. What about integrating RAM with Bentley's equivalent to Revit?

Answer: RAM does already integrate with Bentley Structural

21. When we export our RAM model into Revit there are no deck properties, why is this?

Answer: The deck properties and slab edges are now exported to RAM.

22. Do you have to re-adjust the grid bubbles every time you re-import the RAM model?

Answer: After importing the grid system and adjusting it turn of the grid update in the Import dialog.

23. Once you've made changes to the model in Revit, shouldn't the RAM analysis 'lights' be red due to the addition of new beams? They appeared green.

Answer: That is not a feature at this time but has been discussed for a future release.

24. After talking with many sources regarding whether to start with RAM or REVIT for the model, most individuals recommend starting with REVIT and taking the model to RAM. I have been told that you get a more reliable and stable model when starting in REVIT. You are recommending the opposite. Have you heard or experienced any data corruption or modeling issues with starting a Revit model with RAM?

Answer: You can go in either direction but to have a successful export to RAM you must consider what can and cannot be modeled in RAM. You also have to pay close attention to the analytical model in Revit to successfully export to RAM.

25. Can the shear wall openings be transferred both ways?

Answer: Wall openings are now transferred for lateral walls.

26. Do you still have to break columns at each floor or can you have continuous columns through two floors?

Answer: You can now model multistory columns in Revit and they remain multistory when you update the model from RAM. If you start in RAM they are always imported as story to story.

27. Do column lines import into RAM from REVIT. i.e. adding a new col. line or moving an existing one.

Answer: Yes new grid lines will be imported and existing ones updated.

28. Is RAM compatible with MicroStation?

Answer: RAM Structural System models can be imported into Structural Modeler, PowerStructural Modeler and StructuralDocumentation Center which are built on the MicroStation platform.

29. Can you talk about the transferring of slab edges between Ram and Revit?

Answer: You need to add mapping for the slabs and there needs to be an equivalent floor type already existing in the Revit model.

30. Is STAAD compatible with MicroStation?

Answer: STAAD models can be imported into the Bentley Structural products which are built on MicroStation.

31. What about concrete walls that are off center of the columns? Do they come in correctly and transfer back correctly?

Answer: Walls that are modeled off center of the columns can be exported correctly. The analytical lines of the walls need to line up with the columns lines.

32. When you add members in Revit, do the loads get redistributed (floor loads in psf) in the RAM model?

Answer: After you export the new members to RAM Structural System you have to run the analysis again.

33. What is the best way to manage area loads between both platforms?

Answer: Load combinations must conform to RAM Structural System criteria (no more than five load cases, no combinations comprised of other combinations) to be imported. All load combinations with gravity load cases only are imported into the RAM Frame Steel Post Processor Mode.

34. Can Revit identify frame beams on the framing plans (moment connection symbols)?

Answer: If the beams are modeled with moment connections in the RAM Structural model they will generate moment symbols in Revit. This of course depends on the symbology set in the Revit Structural Settings.

35. Do skewed grid lines export from Revit to RAM?

Answer: Yes, skewed, circular and radial grid lines all export to RAM Structural System.

36. I have had problems with importing double cantilevers from RAM into Revit. One of the cantilevers does not get imported. What should we do?

Answer: This has since been resolved.

37. Discuss how different top of steel elevations is addressed. Example; at a depressed slab condition.

Answer: You need to set the vertical projection for all of the beams to the story level. When the model is exported to RAM all floor framing members are at the same level for analysis. Otherwise you would get unsupported member errors in RAM.

38. You are setting your roof steel to 3D, do you have your columns set to auto detect or top of column?

Answer: You should set the vertical project to top of column or the story level if possible.

39. Does the new link pull RAM defaults from the RAMIS.ini file or do you still need ramdataaccess.ini?

Answer: The link uses ramdataaccess.ini and RAM Structural System uses the defaults in the RAMIS.ini during analysis.

40. Will the slides used in the presentation today be available for download somewhere?

Answer: The recording of the eSeminar and the slides will be available on the Bentley website.

41. Can Autodesk post a copy of the beam tag with reactions?

Answer: The beam end reaction tags are standard in Revit.

42. How do you plan to connect RAM connections to Revit?

Answer: ISM can export RAM Connection data from RAM Elements.

43. As you go through design and transfer data back and forth between RAM and Revit - Do the changes settle down so there is less and less "fix up"?

Answer: If you maintain the analytical model in Revit you will have minimal errors transferring the models back and forth.

44. Does the link handle intentional inconsistencies, such as having a beam slightly off a column center in REVIT, but not wanting to model that in RAM?

Answer: You must always make sure that the analytical lines are consistent in Revit to be able to successfully analyze the RAM Structural model. Use the analytical checks in Revit and address errors before sending the model to RAM. The physical position of the beam is not considered.

45. Will Revit recognize concrete T-beams modeled in RAM Concrete?

Answer: At this time only rectangular beams are supported in the Revit Link. .

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Remove Camber Inch Mark Symbol TN

July 23, 2013, 1:29 pm

≫ Next: Reset RSS Origin TN

≪ Previous: RAM Revit Link Meeting QA Log

Current Revision posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:29:17 PM

Remove Camber Inch Mark Symbol TN

BIM,RAMStructuralSystem,Revit,export,import,RAM-RevitLink


	AppliesTo

	Product(s):	RAMRevitLink
	Version(s):	ALL
	Environment:	N/A
	Area:	Import/Export
	Subarea:
	OriginalAuthor:	BentleyTechnicalSupportGroup

Remove Camber Inch Mark Symbol TN

You can remove the inch mark from the camber on the beam labels.

This requires editing your computer registry.

1. Start Regedit

2. Navigate to: HKEY_CURRENT_USER\Software\Bentley\RAMRevitLink\Options\Import

3. Add a DWORD InchMmSignCamberLabel

4. Set the value to 1 for no inch symbol.

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Reset RSS Origin TN

July 23, 2013, 1:30 pm

≫ Next: Revit Link Coordinate Mapping TN

≪ Previous: Remove Camber Inch Mark Symbol TN

Current Revision posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:30:46 PM

Reset RSS Origin TN

BIM,RAMStructuralSystem,Revit,TechNote,export,import,RAM-RevitLink


	AppliesTo

	Product(s):	RAMRevitLink
	Version(s):	ALL
	Environment:	N/A
	Area:	Import/Export
	Subarea:
	OriginalAuthor:	BentleyTechnicalSupportGroup

Reset RSS Origin TN

If you use the coordinate mapping in the RAM-Revit Link to set the origin location in Revit the coordinates become read-only in the RAM model and cannot be modified with the Revit Link. This tool can be used to Merge two RAM models, Move, Rotate, or Mirror a model.

If you want to merge two models

· Click the Get Model A button and set the path to the model you want to import into Model B

· Click the Model B button to select the model you want Model A imported into

· Set the operation to 1 for Merge and click Execute

Move, Mirror or Rotate

· If you want to Move, Mirror or Rotate your RAM model, first create a new empty RAM model and save it

· Click the Get Model A button and set the path to the new model

· Click the Get Model B button and set the path to the original model

· Select the desired operation number (2 = Move, 3 = Rotate, 4 = Mirror)

· Set the desired insertion point or rotation angle and click Execute

Click the link below to download the spreadsheet. (DA Model Move and Merge)

http://communities.bentley.com/products/structural/structural_analysis___design/m/structural_analysis_and_design_gallery/default.aspx

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Revit Link Coordinate Mapping TN

July 23, 2013, 1:32 pm

≫ Next: Stud Count Bracket Options TN

≪ Previous: Reset RSS Origin TN

Current Revision posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:32:38 PM

Revit Link Coordinate Mapping TN

RAMStructuralSystem,Revit,export,import,RAM-RevitLink


	AppliesTo

	Product(s):	RAMRevitLink
	Version(s):	ALL
	Environment:	N/A
	Area:	Import/Export
	Subarea:
	OriginalAuthor:	BentleyTechnicalSupportGroup

This feature can be used to shift the location of a model between Revit and RSS coordinate systems. Please note, however, that Revit has fixed Origin point which is the same as in RSS (that is 0, 0, 0). One of the possible benefits of using coordinate mapping is the ability to roundtrip a model that uses negative elevations.
There is a new Offset tab page in the Settings dialog.

The RSS point is always set to (0, 0, 0) and this cannot be changed. The Revit point, however, can be changed; it uses feet units when in Imperial mode, and cm when in Metric mode.

The Reset button sets Revit point to be (0, 0, 0).

During the import a dialog box will open to warn the user if the Origin is not (0, 0, 0):

If the model you are importing already has a non-default Origin set that Origin will be used (not the one defined in the Offset page).

Once a global offset has been defined for an RSS model it is saved in the RSS model and treated as a read-only value. (Bentley Support engineer Eric Helmueller has written an Excel spreadsheet that will let you reset the read-only coordinate. DA Model Move and Merge)

http://communities.bentley.com/products/structural/structural_analysis___design/m/structural_analysis_and_design_gallery/default.aspx

During the export the same approach is used: if the offset is not zero, then it will be written to the model and all subsequent updates will use that offset.

Note that previously the link tried to link the bottom most level with the base level in RSS. It doesn’t do that now; instead the user should manually shift the model by using the global offset if they wish to roundtrip such models.

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Stud Count Bracket Options TN

July 23, 2013, 1:34 pm

≫ Next: RAMSS Two Way Decks [TN]

≪ Previous: Revit Link Coordinate Mapping TN

Current Revision posted to Structural Analysis and Design Wiki by SteveCrabtree on 7/23/2013 8:34:00 PM

Stud Count Bracket Options TN

BIM,RAMStructuralSystem,Revit,export,import,RAM-RevitLink


	AppliesTo

	Product(s):	RAMRevitLink
	Version(s):	ALL
	Environment:	N/A
	Area:	Import/Export
	Subarea:
	OriginalAuthor:	BentleyTechnicalSupportGroup

Stud Count Bracket Options TN

Note:

In version 3.4 or newer of the RAM-Revit Link this is an option in the Importer dialog and the registry does not need to be edited.

To remove the brackets from the stud count in the beam labels you need to edit your computer registry.

Open the registry key
"MyComputer\HKEY_CURRENT_USER\Software\Bentley\RAMRevitLink\Options\ Import"
Add DWORD named "EncloseStudCount" with value 1.

Now brackets won't be added to the stud count.

To change to different bracket types you need to add a different entry in the registry called StudCountBracketType in HKEY_CURRENT_USER\Software\Bentley\RAMRevitLink\Options\Import. Its type should be DWORD with value 1 for "{}" and 2 for "[]" brackets. All other values will produce the default brackets "()".

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RAMSS Two Way Decks [TN]

July 23, 2013, 1:41 pm

≫ Next: RAMSS Two Way Decks [TN]

≪ Previous: Stud Count Bracket Options TN

Revision 26 posted to Structural Analysis and Design Wiki by Seth Guthrie on 7/23/2013 8:41:04 PM

RAMSS Two Way Decks [TN]

RAM Structural System, TechNote, selectservices


	Applies To

	Product(s):	RAM Structural System
	Version(s):	14.00.00.00 or later
	Environment:	N/A
	Area:	N/A
	Subarea:	N/A
	Original Author:	Bentley Technical Support Group

Use of Two way decks in RAM Structural System

The table below clarifies how One way and Two way decks can be used in RAM SS v14 or later:

		CompositeDeck		Non-compositeDeck		Concretedeck
Module	DiaphragmType	Oneway	Twoway	Oneway	Twoway	OneWay	TwoWay
RAMSteel	N/A(Rigid)	Simpletributarymethod(1)	N/A	Simpletributarymethod(1)	N/A	Simpletributarymethod(1)	N/A
RAMFrame	Rigid	Simpletributarymethod(1)	N/A	Simpletributarymethod(1)	14.03+FiniteElementmethod(3,4)	Simpletributarymethod(1)	14.03+FiniteElementmethod(3,4)
	SemiRigid	Simpletributarymethod(1-2)	N/A	Simpletributarymethod(1-2)	FiniteElementmethod(3,4)	Simpletributarymethod(1-2)	FiniteElementmethod(3,4)
	PseudoFlexible	Simpletributarymethod(1)	N/A	Simpletributarymethod(1)	N/A	Simpletributarymethod(1)	N/A
	Flexible	Simpletributarymethod(1)	N/A	Simpletributarymethod(1)	N/A	Simpletributarymethod(1)	N/A
RAMConcrete	Rigid(Semi-Rigidpossible)	Simpletributarymethod(1)	N/A	Simpletributarymethod(1)	FiniteElementmethod(3,4,5)	Simpletributarymethod(1)	FiniteElementmethod(3,4,5)

One way deck always requires a complete nodal network, a network of supported beams or walls such that a tributary for every member is defined and encompasses the entire one way deck area.
If you have a semi-rigid diaphragm with a one way deck that is not properly supported by a network of beams, RAM Frame or RAM Concrete may run without warning, but loads will be zero.
When Two way deck is used, only two modules can give results. RAM Frame with a semi rigid diaphragm option (2-way rigid diaphragms are also allowed starting in v14.03), or RAM Concrete. Furthermore, the user must specify the deck effective E value, thickness and Poisson's ratio for those modules to work. The diaphragm will always be meshed, and out-of-plane stiffness will always be assumed. Hence the beams (if there are any) will resist less force compared to a one way system. Any such beams have a centroid alignment to the center of the slab.
No automatic Live Load reduction calculation is performed for members carrying loads from two-way slabs. The reduction to be applied to the Live Load on such members must be assigned to the member in the Modeler (e.g. Layout - Columns - LL Reduction).
RAM Concrete typically considers skip loading for live loads on the beam lines lying under one way decking, if desired. A beam line lying under a two way deck can have skip loading cases only if line and point live loads are applied directly on it. Currently, the surface loading applied to two way decks does not generate any skip loading cases.

Other notable warnings:
RAM Frame, using a Two way deck without using a semi-rigid diaphragm:

RAM Frame: Two-way Deck Found Inside Diaphragm 1 of Story 2. The Diaphragm Type is not Semirigid. Gravity Loads on the Diaphragm Disregarded for the Analysis. Do you want to continue?

RAM Steel - using Two way decks always gives an error of some sort, example:

Warning: Failed to Create Slab Edge Load Polygons for diaphragm 1 on Layout Type Roof. Slab edge loads will not be applied to any beams around the perimeter of that diaphragm. Disregard this warning if the slab edge is Two-way deck.

For levels that include areas of one way deck and two way decks the rules for nodal networks still apply to the one-way decked area. Furthermore, when the level is meshed in Ram Frame or Ram Concrete you will see that the mesh covers the entire floor so that the diaphragm is continuous. This can cause some unexpected behavior in the one-way regions. Specifically the slab can help hold up the beams, indirectly resisting some of the applied loads. For this reason, mixing one and two way decks on one level is not generally recommended.

Semi-rigid Diaphragms for Two Way Slabs

Out-of-plane stiffness is assumed when the deck is two way. There are some general concerns in RAM Frame for these diaphragms. The distribution of gravity loads is determined by meshing the diaphragm and then the program calculates the gravity load that is tributary to each node. . Gravity columns/walls are ignored in the Frame finite element analysis. If you have gravity columns and/or walls, the gravity forces on the lateral members will be inaccurate unless you utilize the consider gravity columns/walls as springs options. However, utilizing this option will have an impact on the lateral analysis as well. The following concepts apply to one way decks with out-of-plane stiffness considered, too.

Consider a five story shear wall building with two way 8 inch concrete slabs. Here is the typical plan.

Two Way Plan

The moments at the base of the walls for a lateral load case in the X direction are 13555 k-ft and the shears are 242 kips. If you run the same load case and include the gravity columns as springs the moments drop to 11163 k-ft but the shears stay the same. The rotation of the building is being resisted by the gravity column springs and out-of-plane diaphragm stiffness. You would get similar results if you modeled all of the columns as pinned lateral columns. As the out-of-plane stiffness of the diaphragm and axial stiffness of the columns increase the moments in the walls would decrease. Conversely, if there was negligible diaphragm stiffness the moments would not change. In the RAM Concrete Shear Wall Module all of the forces, including gravity forces, come from RAM Frame. If you intend to design the shear walls in RAM Concrete it is important to recognize how the Frame results will be impacted when the diaphragm is semi-rigid and out-of-plane stiffness is being considered.

Transfer Forces

A column or wall may now set directly upon a 2-way deck without the need for a beam on the story below. The force from the vertical member will transfer through the meshed slab to the framing below. Since this requires a finite element analysis of a meshed two way slab, it has the same limitations in the table above.

Generally we recommend that the columns or walls that transfer should be modeled as lateral members so that the analysis in RAM Frame will consider those members in the analysis. Thus the program can display or report important information like axial member forces and nodal displacements.

External Links

Bentley Technical Support KnowledgeBase

Bentley LEARN Server

Comments or Corrections?

Bentley's Technical Support Group requests that you please confine any comments you have on this Wiki entry to this "Comments or Corrections?" section. THANK YOU!

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