Problem Description

The self weight of the footing and the pedestal weight is not being factored when carrying out sliding check for isolated footings. The issue has only been observed for sliding check for isolated footings when the self weight factor is not equal 1.

Steps to Reproduce

Here is a summary of the findings:

Restoring force = downward force* coefficient of friction

Downward Force = Footing Wt. + Pedestal Wt. + Soil Wt. + Axial Force in Crit. LC

When one specifies a self weight factor as shown in the picture below, the selfweight factor should be applied as follows: 

Downward Force = 0.6*Footing Wt. + 0.6*Pedestal Wt. + 0.6*Soil Wt. + Axial Force in Crit. LC

However, the software is currently applying the 0.6 factor only to the Soil Wt. , as explained next

Downward Force = Footing Wt. + Pedestal Wt. + 0.6*Soil Wt. + Axial Force in Crit. LC

The selfweight factor should be applied to the footing weight and pedestal weight as well.

Workaround

None

Solution

Will be addressed in the next release STAAD Foundation Advanced.

See Also

Problem Description

When the selfweight is included as part of a primary load case, it is supposed to get included in all combinations involving that primary load case. However the software is currently not doing that and the selfweight is being left out from such combinations. 

Steps to Reproduce

1. In the attached model, the primary load case 1 has selfweight included as part of it.
2. The load combination 101 is created by factoring load case 1 by a factor of 1.
3. Run the analysis and open the .std file that is created by SFA.
4. Note that the selfweight component is missing from the load case 101

(Please visit the site to view this file)

Workaround

Using the Add self weight and deadweight factor icon, add the self weight to all combination cases for which the self weight needs to be included as shown next

Solution

Will be addressed in the next release STAAD Foundation Advanced.

See Also

While analyzing a STAAD.Pro model I get a warning message

  ** WARNING ** A SOFT MATERIAL WITH (1.0 / 1.526E+01) TIMES THE STIFFNESS OF
                CONCRETE ENTERED. PLEASE CHECK.

What does it mean ?

During analysis STAAD.Pro checks whether the E value for the defined material varies widely from the E values for standard materials like Concrete or Steel and generates such warnings when it is so. The intention is to make the user aware of such discrepancies in case it is caused by error in input. Typically such warnings may be generated when the values used for the E are inconsistent with the units. For example E for concrete cannot be 3150 if input unit is pound inches. Similarly E for concrete cannot be 29000 if the input unit is in Kip-ft. So it is important to check for such inconsistencies when warnings like these are encountered.

Sometimes users intentionally define stiff or soft materials and assign these to members/elements to model certain structural entities/connections/boundary conditions in which case such warnings would also be generated but in such cases these may be ignored.

This page contain solutions to miscellaneous analysis related issues

1. My hand calculations do not match the displacements being reported by STAAD.Pro
2. Lifting Analysis
3. I defined a composite deck and I am getting the following warning during analysis   ***WARNING: MEMBER     1 HAS COMPOSITE PROPERTY ASSIGNED TO IT AND HENCE THE MATERIAL CONSTANTS  ARE SET AS THOSE OF STEEL. CURRENT SPECIFICATION IS IGNORED EXCEPT DAMPING RATIO
4. Base plate connection for a tube column
5. Unable to load Bentley.LicLib.dll.Error:126.the specified module could not be found
6. Changing units for existing input data in STAAD.Pro
7. Copying connection templates
8. Error "LoadLibrary failed with error 126: The specified module could not be found" 
9. STAAD.Pro model with connection data in it is not opening in STAAD.Pro SS6 ( 20.07.11.70 )
10. Unable to activate RSS Feed connection message
11. Unable to cast 'STAAD.Pro' COM object to 'OpenSTAAD' object
12. [[** WARNING ** A SOFT MATERIAL WITH (1.0 / 1.526E+01) TIMES THE STIFFNESS OF CONCRETE ENTERED. PLEASE CHECK.]]

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 v14.00 or later:

1. 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.
2. 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.
3. 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 and were altered in 14.07 see Criteria - Diaphragms for details), 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.
4. 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). 
5. 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 (only applies to versions 14.00 to 14.02):

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.

Hybrid Decks

For Hybrid Deck levels, those that include areas of both one way deck and two way deck, the rules for nodal networks still apply to the one-way decked area. If the network is not complete various framing tables errors can occur.

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 meshed slab can help in resisting some of the applied loads, effectively holding up the beams.

There is an option in the Concrete Analysis mode, under Criteria - Analysis to alleviate this effect. 

By not checking the option to "Include Out-of-Plane Stiffness for One-Way Decks in Hybrid Slabs" you are telling the program to use a near zero stiffness element in the one-way deck areas so that the beams have to do the work.

For these reasons, mixing one and two way decks in the same diaphragm is not generally recommended.

Concrete Column design with Two-Way Slabs

In Ram Concrete, the column K factor is determined based on the relative stiffness of the beams to the columns. The stiffness of 2-way slabs is not considered in this calculation, so the user should manually assign the proper K factor for columns supporting 2-way slabs.

As noted above, Live Load reduction percentages also need to be manually assigned.

Semi-rigid Diaphragms for Two-Way Slabs

Out-of-plane stiffness is assumed not only for gravity loads, but also for lateral loads when the deck is two-way and semi-rigid only. When the diaphragm is set to rigid, out-of-plane stiffness is ignored in the lateral load cases. Prior to version 14.07, rigid diaphragm two-way decks considered the out-of-plane stiffness for all loads. This was a major change in version 14.07. Consequently, if you are using version 14.07 or later and relying on slab out-of-plane stiffness to tie your columns together and provide frame action, you must change the diaphragm setting from rigid to semi-rigid. The change can produce instability errors, large deflections, and significantly different Lateral Self-Equilibrium forces when importing forces into RAM Concept in v14.07 compared to earlier versions. Alternatively, contact technical support using a Service Request or a forum post and we can show you how to modify the program configuration to re-activate out of plane stiffness. 

There are some additional 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 and walls are ignored in the Frame finite element analysis when one-way slab are used. For two-way slabs, there are two options for including gravity columns and walls when analyzing gravity load cases in Criteria - Diaphragm (see below).

In general, it is best to use the "Include Gravity Members" option. The vertical spring option does not account for rotational stiffness and will not account for load transfer to supporting slabs when a column or wall is supported by a beam or slab with no column or wall below. Gravity columns and walls are only including when analyzing gravity load cases and the Eigenvalue analysis; they are always ignored when analyzing lateral load cases.

As the out-of-plane stiffness of the diaphragm and axial stiffness of the columns increase the moments in the walls decrease. Conversely, when there is negligible out of plane stiffness to the diaphragm, the moments in the walls would not be affected. (Using version 14.07 or later with rigid two-way decks transforms this behavior so that the slab out-of-plane stiffness is only considered for gravity load cases. See Criteria - Diaphragms for details.)

In the RAM Concrete Shear Wall Module all of the design forces, including gravity load results, come from the RAM Frame analysis. For the design of shear walls it is important to understand the impact gravity columns have on the forces in the walls.

Transfer Forces

A column or wall may set directly upon a 2-way deck without the need for a beam on the story below (using version 14 or later). The force from the vertical member will transfer through the meshed slab to the supports below. Since this requires a finite element analysis of a meshed two way slab, it has the same limitations in the table above, i.e. it only works using Ram Frame or Ram Concrete analysis.

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

We also recommend modeling a transfer beam in addition to the slab when reasonable to do so.

There are some special considerations when using RAM Structural System in conjunction with Ram Concept for transfer slabs. See these topics for further details:

• RAM Concept-RAM Structural System Integration TN
• Modeling Podium Slabs TN

See Also

RAM SS Analysis Types

RAM Frame - Criteria - Diaphragms

RAMSS Common Framing Table Errors

RAM SS Semirigid Diaphragms

Transfer Slabs

Structural Product TechNotes And FAQs

How does changing the ground level affect restraints?

The ground level for Frame analysis can be set through Criteria - Ground level. 

The default is for the model base to be the ground level. This is the bottom of the lowest story in the model story data.

The program will automatically provide a support point or restraint at the base level under every lateral column and wall. Additionally, where lateral columns or walls terminate on a higher story with nothing below them, additional support points are provided.

When you set an upper level to be the Ground Level, the program applies lateral restraint in the global X and Y directions to the diaphragm (or multiple diaphragms) at that story. This is analogous to having a vertical roller support on all the nodes attached to those diaphragms. Nodes that are disconnected from the diaphragm are no longer constrained by any ground level restraint. Any subterranean story below the ground level is also treated the same way.

In models with the ground level above the model base, overturning of the structure will be partially resisted by force couples formed by reactions at the ground level and level below. These reactions result in shear reversals and high shear forces in columns and walls on the subterranean levels.

How does changing the ground level affect wind and seismic loads?

In the calculation of wind and seismic loads, the program assumes the ground level as set under Criteria - Ground level is the zero elevation. All heights using in calculating wind pressures or seismic load distribution are measured up from this ground story. 

Can I have the loads calculated based on an elevated ground level, but not have the ground level restrained?

Not automatically, but user defined story forces are the alternative. We usually recommend to run the model first with an elevated ground level. Then print the Loads and Applied Forces report. Next, create new wind (or seismic) load cases, using the "User Defined Story Force" option under Loads – Load Cases, that are based on that output and delete the original program calculated loads. Finally, reset the ground level to the base.

See Also

RAM Frame - Building and Frame Story Shear

RAM Frame - Wind Loads [FAQ]

RAM Frame - Seismic Loads [FAQ]

Problem Description

Ram Connection for Ram Elements has been installed, but the connection tool bars and features are missing from Ram Elements. 

Steps to Resolve

1. Open the 'e' menu in the upper left. and click License Configuration in the lower left corner.
2. Then click the Start button in the section labeled "RAM Connection" or check the option to "Use a license in each session".
   
   
3. Click OK to save changes.

RAM Elements will enable the RAM Connection integration features.

Converse

If you don't want to use a Ram Connection license or want the Ram Connection features to be available in Ram Elements then uncheck the box that indicates to "Use a Ram Connection license in each session". 

Ram Elements should then be restarted.

See Also

Why does RAM Elements also retrieve a RAM Connection license?

[[RAM Connection is installed, but the Connection button fails to appear in RAM Elements]]

[[RAM Connection v9.0 and RAM Elements]]

Problem

Torsion check as per AISC 360-10 or AISC 360-05 causes STAAD.Pro to crash when such check is carried out for combinations that include

1. dynamic cases as part of it

2. other load combination/s as part of it

Reason

The torsion design can process load combinations created from primary load cases only. In case when load is dynamic or a combination load itself, the program will not process it.

Workaround

Use the LOAD LIST command to ensure that torsion checks are only carried out for cases without the conditions mentioned above.

In case a load combination itself has been included as part of a combination for which torsion check is required, replace the load combination with the corresponding primary load cases within the load combination for which torsion needs to be checked

Solution

Will be addressed in STAAD.Pro SS6 SP4 expected to be released in April/May of 2017. 

The known issues in the release 20.07.11.82 are listed here

Warning : Design Code License is not Activated

[[COMPRESSION attribute is deleted from the ELASTIC MAT/PLATE MAT supports when saving using the GUI]]

[[Crash during torsion check as per AISC 360]]

Problem

When the CAN 1 parameter were assigned to members and these were checked for deflection as per the AISC 360-10 or AISC360-05 codes, the deflection check reported infinity as design result.

Reason

In case of CAN parameter, the x, y, z deflections were not being extracted correctly to compute the correct resultant deflection which lead to the problem

Workaround

None

Solution

Will be addressed in STAAD.Pro SS6 SP4 expected to be released in April/May of 2017.

</

What's New in STAAD.Pro V8i SS6, Build 20.07.11.90 ( 30 March 2017) Issues addressed in:-

• (A) The Analysis/Design engine (46)
• (B) The Pre-Processing Mode (07)
• (C) The Post-Processing Mode (03)
• (D) The Steel Design Mode (00)
• (E) The Concrete Design Mode (00)
• (F) The RAM Connection Mode (01)
• (G) The Advanced Slab Design Mode (00)
• (H) The Piping Mode (00)
• (I) The Editor, Viewer and other modules (00)
• (J) OpenSTAAD (00)
• (K) Documentation and Printing (00)
• (L) licensing / security / installation (01)

(A) Issues addressed in the Analysis/Design engine (45)

A) 01 The AS 4100-1998 code has been updated to include a modification for clause 6.3.3 such that flexural torsional buckling for sections outlined in the clause updated in Amendment 1 now follow the method outlined in AS4600.

A) 02 The design of PMEMBERS in the AS 4100 design routine has been modified such that if there is an issue with the design strength FYLD, then this is now reported once for the member rather than once for each analytical beam which is part of the PMEMBER.

A) 03 The AS 4100 steel design for physical members has been improved to catch the situation where a PMEMBER has been specified section properties to the individual analytical parts (rather than the PMEMBER itself (the recommended approach) and the different parts have been assigned differing section profiles. This will now be trapped and an error message reported.

A) 04 The AS 4100 steel design has been corrected to ensure that the calculation of Mox,c is determined from the member end that has the largest axial force, rather than simply taking the value from the end of the member.

A) 05 The AS 4100 steel design routines have been improved in determining the effective area of wide flange sections that are classified as non-compact or slender.

A) 06 The AS 4100 steel design module has been enhanced with a wider selection of steel grades as defined in the standard.

A) 07 The AS 4100 steel design module has been enhanced to include checks for interaction of shear and bending using the interaction method as per clause 5.12.3

A) 08 The AS 4100 steel design for PMEMBERS has been updated to ensure that the PBRACE command can process lists in the form "a TO b"

A) 09 The output reporting for PMEMBERS designed to the AS 4100 steel design code has been improved to include the slenderness details.

A) 10 Further to A) 09, should a PMEMBER designed to the AS 4100 steel design code fail the slenderness checks, then this is now reported in the output file and confirms that no further checks can be performed.

A) 11 Further to A) 10, should a PMEMBER designed to the AS 4100 steel design code fail the slenderness checks, the governing criteria is now reported as 'Slenderness'. Previously in this situation the governing criteria was left blank.

A) 12 The AS 4100 steel design of web tapered members has been improved to include the effect of clause 6.3.4 in determining the member compression capacity. In order to determine the value of 'Nom', an assumption is made that the profile is prismatic and uses the expression from clause 4.6.2, using the shallowest profile of the tapered member which is on the conservative side.

A) 13 The AS 4100 steel design routines have been enhanced by adding the alternative method for determining the nominal in plane member moment capacity, Mi as defined in clause 8.4.2.2 for doubly symmetric I sections and rectangular and square hollow sections.

A) 14 The AS 4100 steel design routines have been enhanced by adding the alternative method for determining the nominal out-of-plane member moment capacity, Mox as defined in clause 8.4.4.1 for doubly symmetric I sections without transverse loading.

A) 15 The AS 4100 steel design routines have been corrected to ensure that Mix and Miy are calculated when there are moments in EITHER direction. Previously, these were only being calculated if the was an axial compression and moments in BOTH directions.

A) 16 The AS 4100 steel design routines have been enhanced with alternative expression for the biaxial bending check as per section 8.3.4 for doubly-symmetric I-section, rectangular and round hollow sections.

A) 17 The AS 4100 steel design routines for calculating the nominal section moment capacity reduced by the axial tensile or compressive force as defined in section 8.3.3(a), for doubly symmetric compact I sections has now been implemented when working with members subject to single axis bending about their minor axis.

A) 18 The AS 4100 steel design routines for calculating the nominal section moment capacity reduced by the axial tensile or compressive force as defined in section 8.3.2(a), for doubly symmetric compact I sections has now been implemented when working with members subject to single axis bending about their major axis.

A) 19 The AS 4100 steel design routine has been improved for determining the minor axis shear capacity for welded wide flange sections such as WB or WC, so that it now only uses the depth between flanges rather than the overall depth which is used for rolled sections.

A) 20 The design of PMEMBERS to the AS 4100 steel design code where the load has been defined as assigned on the top flange (i.e. LHT=1), has been corrected to ensure that the value of kl is determined from table 5.6.3(2) depending on the restraint.

A) 21 The design of PMEMBERS to the AS 4100 steel design code has been corrected to ensure that the value of the ALB parameter is correctly assigned to the physical member.

A) 22 The steel design routines for AISC 360, IS800 and CSA S16, were liable to crash if the file included a SELECT command which had a list that included plates as well as members. This situation is now trapped and the plate numbers will not cause the design to fail.

A) 23 The AISC 360 steel design deflection check routine has been updated to ensure that if a member SELECT is used, the calculations used in the output are based on the final section property.

A) 24 The IS800-2007 steel design deflection check routine has been updated to ensure that if a member SELECT is used, the calculations used in the output are based on the final section property.

A) 25 The CSA S16 steel design deflection check routine has been updated to ensure that if a member SELECT is used, the calculations used in the output are based on the final section property.

A) 26 Further to A) 05, the AS 4100 steel design routines have been improved in determining the effective area of wide flange sections that are classified as non-compact or slender.

A) 27 The steel design routines that perform a deflection check have been updated to catch a situation where an internal element array would overflow and cause the analysis to crash.

A) 28 The AISC 360 steel design for tapered members has been updated to ensure that clause H2-1 is correctly determined and reported.

A) 29 The deflection check performed in the AISC 360 routines for cantilever members has been updated to ensure that the values of deflection in each of the three local axes are extracted from the model correctly.

A)30 The IS 800-2007 steel design routine has been updated to ensure that if the section database for channel profiles includes the value of Ct, that is the distance from the back of the web to the centroidal axis, then that value is used directly. Previously this value was being calculated from the section dimensions even if it existed in the database.

A) 31 The Aisc ASD - 9th edition steel design routines for calculating the bending capacity Fb for web tapered members defined as I-Section UPT profiles, where the flanges have different dimensions, have been modified to ensure that rt accounts for the flange that is in compression.

A) 32 The BS 5950 steel design routines have been updated to extend the design of tubes and pipes to include SHS, RHS and CHS profiles.

A) 33 The IS 800 2007 LSD has been updated to improve the determination of the section capacity for members under very high shear where V/Vz>0.6, an additional check has been introduced which limits beta-y to 1.0

A) 34 The BS 5950 steel design routine has been updated to ensure that rectangular and circular section profiles that are not supported are reported as such in the design output.

A) 35 The BS 5400 steel design routine has been updated to improve the routine that determines the gross sectional area of a wide flange that has been specified in a UPT and can have different flange dimensions. Previously, the gross sectional area would have been determined using the dimension of the top flange as that for the bottom flange.

A) 36 The NS 3472 steel design module has been updated to ensure that if a member has been assigned a non-supported profile for this code, then a warning message is posted in the user report. Note the previously some section profiles would appear to have been designed, but in the post processing>Beam>Steel Design would show the ratio as '1#QNAN'

A) 37 The EN 1993-1-1 steel design routine has been enhanced with an additional test on a UPT General Sections. This will design the member as a shape based on the GST parameter. However, if the UPT profile does not have sufficient dimensional information data, then this will report as an error in the design output.

A) 38 The Aisc ASD - 9th edition steel design routines for calculating the allowable compression capacity Fa (section Appendix B5.) for web tapered members defined as I-Section UPT profiles which have slender elements and where the flanges have different dimensions, have been modified to ensure that Qs accounts for the actual flange dimensions, and no longer uses an average flange size.

A) 39 The AISC ASD - 9th Edition steel design routines have been updated to improve the design of wide flange sections which have differing sized flanges. The program will now check to identify which is the compression flange and use the elastic modulus for that rather than simply picking the smallest elastic modulus which could lead to an overly conservative design.

A) 40 The torsion checks with AISC 360 steel design to Design Guide 9 (DG9) has been updated to catch if any load combination is defined with a dynamic primary load case. This is currently outside the scope of this routine and if any such cases were included would cause the analysis to crash.

A) 41 The IS 800-2007 steel design routines for web tapered members have been updated to ensure that the details of the web classification are reported for the critical location on the member rather than the profile at its start location.

A) 42 The concrete design routines for IS 13920 have been updated to trap the occurrence of using a load combination for the gravity load case (defined with the GLD parameter), which is a combination case that itself references a separate load combination. Previously, if such a load combination had been used, this would result in a crash of the analysis. At this time rather than using an included combination, it is suggested to create an equivalent primary load case and use the REPEAT LOAD method instead.

A) 43 The ASME NF design codes have been updated with the addition of a check to clause NF-3322.(d)(1)(6)-12 for determining the calculation of allowable bending stress for box sections. Now when the value of L > Lc, then the allowable capacity is calculated as 0.6Fy rather than 0.66Fy.

A) 44 The steel design routines to AS 4100 have been improved to ensure that when determining the slenderness reduction factor (clause 6.3.3), a factor of zero is not produced which could occur on very small members. This would in the design reporting the members having a member compression capacity and ultimately a failure ratio of infinity.

A) 45 The details of the AISC 360 interaction check H2-1 have been updated so that the values of 'Fcbw' and 'Fcbz' for the Tensile check both used the elastic modulus for the tensile side. Previously, these had been based on the elastic modulus of the compression side, however, the resulting calculation and ratio remains unaffected.

A) 46 The recent introduction of the CAN 2 option in the IS 800-2007 Indian steel design module to clasify a member as simply supported for the bending checks was however being used to clasify the member as a cantilever for the servicabilty checks. This would over estimate the member local deflection and result in a conservative ratio when the member was checked for serviceability.

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(B) Issues addressed in the Pre-Processing Mode (07)

B) 01 The description and note of the value KZ for AS 4100 design code parameters has been updated to provide a clearer meaning of the use of this parameter in the program to the engineer.

B) 02 The GUI has been updated to ensure that use of the European design codes is correctly logged. Previously this could lead to the UI not allowing parameters to be added to the datafile.

B) 03 The GUI has been updated to ensure that a new set of concrete, timber or shearwall design code parameters can be added to a model. In the last version of the program, the GUI would prevent the user to add parameters to a design code that was not already included in the file and suggest that the appropriate license be activated.

B) 04 The GUI has been updated to improve the STD file reading routines which process the IS 802 parameter ELA for compression slenderness checks. This parameter is valid from 1 to 7 (refer to the Technical Reference manual section 11D.3), however if the file included a value greater than 4, it was treating this as an error. Now any value from 1 to 7 can be used.

B) 05 The AS 4100 steel parameters dialog has been updated such that if the 'Physical Member Mode' has not been set (icon in the Steel Design Toolbar), only parameters that can be assigned to analytical beams will be displayed. Parameters such as PBRACE and LHT will not be displayed.

B) 06 The AS 4100 steel parameters dialog has been updated such that if the 'Physical Member Mode' has been set (icon in the Steel Design Toolbar), only parameters that can be assigned to physical members will be displayed. Parameters such as DFF, DJ1, DJ2, etc. will not be displayed.

B) 07 The GUI has been updated to ensure that if a Reference Load Case is defined, highlighted in the Loads dialog and the Delete button pressed, the program correctly removes the reference load case and does not crash.

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(C) Issued Addressed in the Post-Processing Mode (03)

C) 01 The Member Query details for a steel design on a member that has been designed to the Russian steel code, has been updated to ensure that the direction of the axial force reported is not mirrored. Previously, a compression force would be reported as tension and vice versa.

C) 02 The member Query dialog has been updated for Russian steel designs to ensure that the actual member status, ire. PASS/FAIL is correctly reported.

C) 03 The post processing routine that displays the result of a member that has been designed to BS 5950 and failed due to slenderness, will now display this cause in a member query dialog.

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(D) Issues Addressed in the Steel Design Mode (00)

(None)

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(E) Issues Addressed in the Concrete Design Mode (00)

(None)

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(F) Issues Addressed in the RAM Connection Mode (01)

F) 01 The RAM Connection module has been updated to report the version of STAAD.pro that it is within rather than 10.0.0 which is the version of the RAM Connection from which the dlls originated.

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(G) Issues Addressed in the Advanced Slab Design Mode (00)

(None)

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(H) Issues Addressed in the Piping Mode (00)

(None)

Top

(I) Issues Addressed in the Editor, Viewer and other modules (00)

(None)

Top

(J) Issues Addressed in OpenSTAAD (00)

(None)

Top

(K) Issues Addressed with Documentation and Printing (00)

(None)

Top

(L) Issues Addressed with licensing / security / installation (01)

L) 01 The additional licenses that can be selected from the Start Screen now have an additional warning notice added informing the user that selecting these may incur a charge.

Top

I installed STAAD.Offshore program however the wave loads generated seem to be off by 1000. The distances along the member length at which the loads act, seem to be values corresponding to mm units although the units are supposed to be in meter.

The problem is due to an issue with the version of OpenSTAAD OEM that got installed with the STAAD.Offshore software.  Installing the current version of OpenSTAAD OEM should address the problem. So having an updated version of Bentley OpenSTAADOEM ( like 08.02.09.47 ) is the key. However there is a catch. If you have an updated version of Bentley OpenSTAADOEM ( like 08.02.09.47 ) already installed and you try to install the STAAD.Offshore software, the installation of STAAD.Offshore would stop telling you to uninstall the installed version of Bentley OpenSTAADOEM as it is more updated compared to what STAAD.Offshore would require. So the trick is to uninstall any recent versions of Bentley OpenSTAADOEM, install STAAD.Offshore and then reinstall the more updated version of Bentley OpenSTAADOEM. The simplest way to get the latest Bentley OpenSTAADOEM installed is to reinstall STAAD.Pro which would automatically install Bentley OpenSTAADOEM and then you will not have the problems you reported for STAAD.Offshore.

1. Should the static (gravity) loads in the STAAD Pro Load Combinations be Excluded when Analyzing for Transportation Cases
2. Can we specify Marine Growth above the Still Water Level in STAAD.Offshore?
3. When I generate the STAAD file with wave loads using the STAAD.Offshore module, the file throws up errors while opening in STAAD.Pro and the Wave Load Cases are messed up.
4. I have specified the added mass coefficient and the drag coefficient as zero. However, STAAD is still generating Wave Loads in the Vertical direction.
5. When I try to open my staad.pro model in offshore, I receive the error: “Structure file has syntax errors. check the <filename>.err file for reasons”. What is the cause of this error ?
6. I added a section to the STAAD.Pro section database and used it in my model. Now I am trying to open the STAAD.Pro model in STAAD.Offshore and I am getting error messages saying “structure file has syntax errors”. How do I get Offshore to recognize my defined sections ?
7. Type PIPE/TUBE/OPEN/PRISMATIC Cannot be Established for Some Members
8. Is it possible to specify the heave + roll and heave –roll in the same load case?
9. Joint Lumped Inertia Force System vs Member Distributed Inertia Force System
10. Trap Load Beyond its Length. Full Length Assumed
11. Not very clear with the input regarding the flooded members and appurtenance members in structure member properties in STAAD Offshore.
12. In the main menu it says metres and Kilonewtons where as in the general tab for water mass density not sure what to apply either kg/m3 or kN/m3 ? If we apply in kN/m3 the wave output shows 10.2 kg/m3 which is not right.
13. [[Wave loads generated in STAAD.Offshore are off by 1000]]

Are the applied surface loads cumulative?

No, in RAM Structural System only the top applied surface load counts. The underlying loads are not deleted however, so if you delete the top load you can see the original load underneath. If too many load layers are applied to a model, a polygon error can occur when processing the loads. For this reason it is always best to remove any existing surface loads before modeling new layers.

Also note, this is different than the behavior in RAM Concept. In that program, overlapping surface loads are cumulative. Consequently, when Direct Gravity loads are imported from RAM SS into Concept, they are converted into equivalent separate polygons that do not overlap.

Is the structure self-weight included in the loads?

That depends on the settings under RAM Manager - Criteria - Self-Weight. Here the user can automatically include beam, column, wall or deck self-weight. Note, open web steel joists self-weight is never included.

On the right hand side of the dialog box are the settings for self-weight as it applies to the building mass which is used for seismic loads, dynamic analysis and for P-Delta calculations.

For composite beam design, the self weight is always considered part of the Construction Dead Load. Hence, if all the self weight options are turned on, and there is no other load present during construction, the user applied CDL might be zero.

For open web steel joist systems it's important to note that no self-weight is applied for the steel joists. The reason for this is primarily that the unit weight of steel joists can vary depending on the manufacturer and the configuration of the diagonals. The user should always include extra dead load in the surface loads to account for estimated joist self weight.

In order for the steel gravity beam and column self weight mass to be considered in RAM Frame, it is imperative that those modules be run first, using the design-all process. So long as the RAM Manager indicates a green light next to each of those modules, RAM Frame should have the latest member self weight data available. Freezing the design of all gravity beams and columns is another way to ensure that member self weights are always considered.

Note, in RAM Frame, under Loads - Masses, the program calculated diaphragm mass totals can be overridden with User Specified values, normally using calculated masses is advised. There is a similar dialog box for the total Gravity Loads which is used to determine program generated notional loads.

Is the additional weight of concrete due to beam sag or "ponding" considered?

No, the self-weight of the deck is based on the thickness and weight parameters set in the Modeler - Deck Properties. When beams sag under the weight of the deck it is a common practice for the topping concrete to be leveled off which adds additional weight to the system assuming it's not cambered or shored. This additional weight should be incorporated into the applied construction dead loads (and masses).

How are partition loads handled.

The Partition Load is an additional Live Load; it is treated as an unreducible Live Load and will not be reduced. It is in addition to the loads specified as Live Load. Partition loads are defined variously by the Codes, some as Dead Load and some as Live Load. For those codes that define Partition loads as an unreducible Live Load, those should be specified here. For those Codes that define Partition loads as a Dead Load or as part of the regular Live Load, those should be included as part of the Dead Load or Live Load accordingly.

Unlike construction live load, the partition live load is not a portion of the total live load entered. You can apply 0 Live Load and still apply 15 psf Partition Live load, for example.

Partition loads are not automatically included in the seismic mass. The total Mass DL should be increased to account for partition weight as required by the code for seismic loads.

How is the self weight of Concrete Beam determined?

The program calculates rectangular beam unit self-weight based on the area of the beam times the "Unit Weight of Self weight". The other "Unit Weight" parameter is only used in calculating the elastic modulus, E, of the member.
The Concrete slab can independently be included in the self weight, so in cases where there is a concrete slab and rectangular concrete beams the weight of the concrete times the thickness of the slab and the width of the beam is double counted.

 
To alleviate this problem, "T" shaped beam sections are handled differently. With T beams, it's only the area of the stem below the slab that is applied as the beam self weight.

.

Why are my Roof Live loads ignored in the design?

RAM Structural System currently considers Snow OR Roof LL, but not both at the same time. In RAM Manager under Criteria - Members loads there is a toggle to select which the program should consider. Set the toggle to “Consider snow loads, Ignore roof live loads” when snow loads are modeled.

Note: Live Reducible, Unreducible and Storage type loads are always considered, it is only the Live - Roof type loads that are excluded when the option to consider snow loads is turned on.

Are my snow loads automatically added to the building weight for seismic load determination?

No, the program only uses the assigned Mass Dead Loads plus whatever self-mass options are turned on under RAM Manager - Criteria - Self weight when determining the total building mass or weight used in Seismic load determination (and in P-Delta calculations). The user should increase the Mass DL of applied surface loads to account for the weight of the snow load (or a percentage of the weight as required.

Note, the provided templates for load combinations do correctly consider snow load acting simultaneously with Dead, Live and Seismic loads, however.

This also applicable to Storage Live Loads, even if the magnitude entered for the Storage Live load is large (e.g. > 125 psf) no portion of the storage live load is automatically considered in the seismic mass. The user must increase the Mass DL (or manually alter the masses in Ram Frame) when part of a storage live load needs to be added to the seismic mass.

How can I apply a drift snow load?

Within the snow loads, only the top load counts. Since only the top snow load counts, the drift snow load should typically taper down from the max value to the flat-roof snow load as a minimum. The program gives a warning when any portion of the sloping plane of snow load is 0 or less magnitude.

In general, it’s best to define snow drift loads with M1 and M2 set to the highest value, and M3 set to the flat roof level. Then the loads can be applied in rectangular or trapezoidal areas as required. In the image below, the total snow load on the left is 50 psf tapering down to 30 psf on the right. This would be used in conjunction with a flat roof snow load of 30 psf applied first to the whole roof.

See Also

[[RAM Steel Beam Pattern Loading]]

RAMSS Seismic Loads FAQ

Product TechNotes and FAQs

Structural Product TechNotes And FAQs

Known Issues in STAAD.Pro SS5

Known Issues in STAAD.Pro SS6 

It may be worth noting that all issues that are known at the time of release are documented as part of the Known Issues section within the Readme file that is provided as part of the installation and can be accessed through Start > All Programs > Bentley Engineering > STAAD.Pro V8i ... > Read Me as shown next

This would open a HTML page. One can click on Known Issues under Local Information on the left side of the page to get a list of known issues.

Query:

In the seismic definition window, if I select IS1893 code and click on Generate tab, there is a error message -- "Creation Failed". How to solve this?

Solution: 

The error message is related to seismic parameter auto-generation as per IS1893 code in STAAD.Pro Select Series 6 (build 20.07.11.33) version. This problem has occurred because of the fact that Dll1893.dll has not been registered at the time of installation of the software. You need to register this dll file (Dll1893.dll) manually. The procedure is mentioned below--

1. Go to the following location—

X:\SProV8i SS6\STAAD

Where x is the local drive where you have installed STAAD.Pro SS6 version.

2. Locate the “Dll1893.dll” file and copy the full path. The path will be as—

C:\SProV8i SS6\STAAD\Dll1893.dll

3. Open the command prompt in administrator mode (go to Run >type “cmd” and select the option “Run as Administrator”)

4. Write the following command—

regsvr32 “C:\SProV8i SS6\STAAD\Dll1893.dll”

5. Press Enter. You should see a regsvr32 window, confirming success. Click on Ok.

6. Now run STAAD and go to seismic definition to check.

Note: This problem has been rectified in STAAD.Pro SS6( build 20.07.11.45).

Why don't the column design forces equal the sum of the beam reactions?

There are 2 things that contribute to the situation noted above.

• In determining the worst design conditions as required by code, the program skip loads the live load around the column to create the worst case of axial load and bi-axial bending. When a live load is “skipped” on a side (i.e., not applied), it is not included in the total axial design load which appears on the column design or column summary reports. This means that sometimes the reported design load does not include all beam live load reactions applied simultaneously. Please refer to the RAM Steel Column manual, section 3.4.1 Unbalanced Moments as well as Tables 3-1 and 3-2 for details. If you are looking to print total loads for the design of your foundations, you should print either the Column Load Summary report, or the Foundation Loads report from the RAM Manager Post-Processing menu.

  Note, in version 14.07 and later, the Steel Gravity Column Design report was enhanced to include more information. It now includes a section called "Controlling Axial Column loads" which lists the maximum axial demand used in the Pu/phi Pn checks, and another called "Controlling Combined Column Loads" listing the critical combination of axial and moments that gives the highest interaction ratio. 

  
  

• There are different live load reduction requirements for Beams and Columns. This will lead to different loads being reported in the member designs. To see the live load reduction percentage used in the column design, print the full Loads report.

Why aren't the column reactions from RAM Steel equal to the reactions from RAM Frame?

There are differences in the RAM Steel and RAM Frame program that affect the reactions you see in each program.

In the RAM Steel Column Module, the column loads are determined directly from the reactions of the simply supported beams. Think of it like simple tributary analysis. The total loads are simply added together (and reduced where Live Load reduction applies).

RAM Frame, on the other hand, determines column forces from a Finite Element Analysis. This method takes into account relative stiffness of the elements in the model to determine how loads are distributed. Refer to the Analysis Types article for more.

Consider these simple examples that illustrate how the FEA of RAM Frame produces more accurate results for the lateral frame reactions. 

For complex, multi-story models, or structures where the frames are linked by a rigid diaphragm this difference in behavior can be quite significant.

How can I confirm the orientation of a square column?

When reviewing the member forces, reactions or other results it is important to understand the relationship between column orientation, footing orientation and the global axis systems.

The following diagram shows the various orientation options for column as they appear in plan. Orientation angles in the RAM Structural System are always measured counter-clockwise from the positive “x” axis. This same rule applies to deck angle, lateral load angles, etc. Note that for Tube sections or rectangular concrete columns it is more difficult to be sure of the column orientation since it doubly symmetric. For those sections, the long dimension (presumably the “H” dimension for your concrete sections) is parallel to the angle of the member.

The orientation can be confirmed in the Modeler by using the layout – column - show command or in RAM Frame by checking “Orientation” under the View – Members command. Once the orientation of the column is known, it is easy to reconcile the sign convention for member shears and moments as depicted in the following figure:

For beams, the sign convention is similar. The orientation vector for beams always points upward, so positive moments occur when there is compression in the top flange.

When foundations are modeled, they are typically oriented the same as the column. When this is done, the major axis moments in the column result in major axis moments on the footing as well. It is only when the footing is rotated to the axis of the column that the forces get translated. For more information on footing orientation see the foundation manual.

Why are the column eccentricity and moments all zero for some steel columns?

In the gravity steel column design there are a few cases where the eccentricity is automatically set to zero:

1. Where eccentricity is specified to be zero by the user in the Modeler
2. Where the column supports a beam with a cantilever extension we assume a perfect fulcrum connection for the beam and no moment transfer to the column in this case. Furthermore the program is assuming some sort of cap plate connection and ignoring the eccentric moment in the column in both axes which may be unconservative.
3. When the column is a hanger.
4. Connection eccentricity is also not considered in the design of lateral steel columns in RAM Frame. The assumption here is that typical brace frame connections act through the column centroid work-point (and moment frame connections are fixed). Where you have a lateral column supporting a beam with an eccentric shear connection it is worthwhile to cross check the column design in Ram Steel Column.

How can I see the thrust that results from model a sloped column?

When the columns are modeled as gravity members the thrust component is not considered in the design of the column (or the lateral forces on the structure as a whole).

For this reason it is recommended to model sloped columns using lateral members. In that case the finite elements are correctly formulated in the Ram Frame analysis and any thrust components will automatically be accounted for. Keep in mind, where a diaphragm is rigid, the diaphragm will transfer those thrust component to various vertical frames directly. If you want to see the thrust as an axial force in a beam, the beam will also need to be lateral and the beam column node freed from the diaphragm constraint.

Can lateral column base plates be designed?

The design of base plates in RAM Steel is limited to gravity columns. We offer Ram Connection for the complete design of moment frame or braced frame (as well as pinned) base plates according to the latest codes.

Can I assign a section such as a HSS or channel to a beam?

Currently, only I-shaped (wide flange) sections can be assigned to beams in RAM Connection. It is not possible to assign other section types, like HSS or channels, to beam members, though they can be used as columns or braces in many connection templates.

What is the difference between Basic Connections and Smart Connections?

The RAM Connection Manual defines these connections as follows:

Basic Connection:  A connection template that can automatically adjust the geometry (position or dimensions) of the connection pieces to fit the connection members. It does not calculate the quantity or dimensions of the connecting pieces (bolts, plates, etc) to resist the applied forces.

Smart Connection: A connection template that can automatically calculate the quantity and dimensions of the connecting pieces (bolts, welds, plate sizes etc) to resist the applied forces.

When basic connections are designed, the program searches through a list of predefined connection templates and selects the first connection in the list that satisfies the design requirements.

When smart connections are designed, the program optimizes the connection parameters. See the RAM Connection Manual for a list of parameters that are optimized for each connection type. If a parameter is not optimized, the program uses a default value that be modified in the Connection Pad as needed.

Some complex connection templates like gusset pate or base plates only have a smart variety. 

Where are the abbreviations used for joint types and connections defined?

The abbreviations are defined in the RAM Connection Manual (available from the help ? or as a pdf from the Windows Start menu). The naming conventions for both joints and connections are listed in Chapter 2, The Connection Database - Database organization. Here is a list of the joint types from that section:

1. Beam – Column Flange (BCF)
2. Beam – Column Web (BCW)
3. Beam – Girder (BG)
4. Beam Splice (BS)
5. Column Splice (CS)
6. Continuous beam over column, column Cap (CC)
7. Column, beams and braces (CBB)
8. Chevron braces (CVR)
9. Vertical X braces (VXB)
10. Column – Base (CB)
11. Column – Base – Braces (CB)

What kinds of forces are considered in various connection types?

In the Joint help is a table of the forces considered in each of the differnt connection types. 

How can I change the design code (AISC 360 or BS 5950) or the design method (ASD or LRFD)?

In general, once a connection has been assigned it is associated with a specific design code. In some cases you can change the design code for a connection after the face, but when changing county codes, the connections will have to be replaced after changing the code. 

RAM Connection Standalone version 10.0 or earlier:

1. Click on the Design menu tab at the top of the program window.
2. Find the Assignment toolbar.
3. Double click on the small square box with arrow pointing to the lower right corner to open the Customize Connection Design dialog. Beginning in v10.0, the Customize Connection Design dialog is opened by clicking on the button in the Assignment toolbar that matches the design code selected.
4. Edit the design code (or design method in version 8).

Note, in Ram Connection Stand-alone version 9.0, changing the design code does NOT retroactively alter the assigned code for the existing joints in the file. This was done intentionally so that the user can have some joints designed to one code and other joints designed to another code within a single file. Consequently, if the design code for existing joints needs to be changed, the code should first be changed, then reassign connections to the joints.

Ram Connection Stand Alone version 11.0:

1. The current design code used for any future assigned connections to joints within the current model or any model is set under the Design Tab. 
2. Use the drop down list at the right of the main graphic to change the code for an existing connection. Note, changing from ASD to LRFD or 2005 to 2010 is generally supported, but changing countries will invalidate most connections since different design templates are used.   

RAM Connection 10.0 or earlier for RAM Structural System:

1. Click on the Design menu tab at the top of the program window.
2. Find the Assignment toolbar.
3. Double click on the small square box with arrow pointing to the lower right corner to open the Customize Connection Design dialog.
4. Edit the design code (or design method).

RAM Connection 11.0 for RAM Structural System:

1. The current code for assigning connections is selected in the Design menu similar to Ram Connection 11 Stand Alone.

RAM Connection 10.0 or earlier for Ram Elements:

The design code and design method is controlled by the code selected for design when performing a design in the RAM Elements model. To change the design code or design method, redesign the model and choose the desired design code.

Changing the design code will not automatically update generated load combinations. After changing the design method, delete and regenerate the load combinations.

 RAM Connection 11.0 for Ram Elements:

1. The current code for assigning connections is selected in the Modules menu.

Why is the controlling load condition reported as a single load case?

RAM Connection completes a design check for all load conditions, including individual load cases and load combinations. For some connection types, such as a base plate connection with wind uplift, the design for an individual load case may control the design. The single load cases can be removed from consideration as follows:

Open the "Customize Connection Design" dialog using the instructions under "How can I change the design code (AISC 360 or BS 5950) or the design method (ASD or LRFD)?" above. In the dialog, click on the button marked in red below to select the load combinations only.

RAM Connection Standalone (Versions Prior to v9.0)

1. Enter the Connection Pad by either double-clicking the large 3D display of the connection or clicking on the Design menu tab – Connections toolbar – Edit.
2. In the Connection Pad, click on <Loads> to open the Loads worksheet.
3. Click on the Load # associated with the load case and then click on the Delete button on the keyboard to delete it from the worksheet.

Please note that this will not permanently delete the load case results from the worksheet. See frequently asked question above for details.

When designing a base plate connection, the ACI 318 Appendix D checks are not completed.

Since the ACI Appendix D checks are based on ultimate limit state design, RAM Connection will only complete the ACI Appendix D checks if LRFD is selected for the design method. See frequently asked question above for information on changing the design method.

When shear lugs are included in the base plate connection, the shear is assumed to be resisted entirely by the shear lug and the shear demand in the anchors will be 0.

Information that is modified in the Connection Pad is not saved after clicking the Save button and exiting the dialog.

Any item in the Connection Pad that is marked with a blue arrow (version 9.0 and later) or a red arrow (versions before 9.0) is defined in a dialog outside the Connection Pad. These parameters can be edited in the Connection Pad, but the information will be lost after closing the dialog. To change the parameters permanently, modify the values in the dialog where the information is initially defined. Edit the Joint to modify loads, sections, materials, etc. Edit the seismic provision options in the Customize Connection design dialog.

I'm designing a connection with seismic provisions, but the Ry and Rt values don't look right, what's wrong?

Ry (Yield strength ratio) and Rt (Tensile strength ratio) are properties of the material in Ram Connection. The can be reviewed using Home - Databases - Materials - Edit.

To add your own materials with different values, refer to the wiki Creating custom elements in RAM Elements which also applies to Ram Connection.

Note, imported materials from RAM Structural System or STAAD.pro may not have the expected values for Ry and Rt since those are not directly supplied by either of those applications. For Ram Connection users with imported RAM SS files, edit the imported RAM SS materials as shown below (or reassign different steel material to the members):

Refer to Ry and HSS Steel Materials Imported from RAM Structural System for more information on Ry and HSS members that is specific to RAM Connection for RAM Structural System.

For STAAD users, be careful to define the proper values when using the RAM Materials dialog box within the connection mode.

For further details refer to Tips for Using RAM Connection within STAAD.Pro [TN]. and How to Customize a RAM Connection Template in STAAD.Pro 

See Also

Troubleshooting Errors when Assigning Connections

Structural Product TechNotes And FAQs

This document is organized in a way that newer revisions appear at the top.
Therefore, section numbers will keep decreasing from top to bottom. Also refer
to the What's New section of the Online Help for Major New Features. This
document outlines fixes and last minute changes.

Copyright (c) 1997-2016 Bentley Solutions Center

What's New in:-

STAAD.Pro V8i SS6,

• Build 20.07.11.90 (30 March 2017)
• Build 20.07.11.82 ( 12 July 2016)
• Build 20.07.11.70 (22 March 2016)
• Build 20.07.11.50 (03 December 2015)
• Build 20.07.11.45 (30 September 2015)
• Build 20.07.11.33 (23 June 2015)

.

STAAD.Pro V8i SS5,

• Build 20.07.10.66 (14 January 2015)
• Build 20.07.10.65 (29 October 2014)
• Build 20.07.10.64 (22 July 2014)
• Build 20.07.10.41 ( 26 November 2013)

.

STAAD.Pro V8i SS4,

• Build 20.07.09.31 ( 11 March 2013)
• Build 20.07.09.21 ( 20 December 2012)
• Build 20.07.09.311 ( 14 August 2012)

.

STAAD.Pro V8i SS3,

• Build 20.07.08.22 ( 16 May 2012)
• Build 20.07.08.20 ( 16 September 2011)

.

STAAD.Pro V8i SS2,

• Build 20.07.07 QA&R ( 24 February 2011)
• Build 20.07.07 ( 13 October 2010)

.

STAAD.Pro V8i SS1,

• Build 20.07.06 QA&R ( 18 March 2010)
• Build 20.07.06 ( 23 December 2009)

.

STAAD.Pro V8i,

• Build 20.07.05 ( 21 May 2009)
• Build 20.07.04 ( 30 October 2008)

.

STAAD.Pro 2007, Build 03 ( 8 July 2008)

STAAD.Pro 2007, Build 02 (14 September 2007)

STAAD.Pro 2007, Build 01 (29 June 2007)

What RAM Concept Can Design

RAM Concept is intended for the analysis and design of elevated (suspended) concrete floors and mat foundations (rafts). These floors or mats can be conventionally reinforced concrete (RC), post-tensioned concrete (PT), or a hybrid. A hybrid floor is one that contains both RC and PT areas. For example, most PT floors have some areas, such as pour strips or elevator core slabs that are designed with mild reinforcement.

RAM Concept can also design the following:

1. Pile-supported mat foundations
2. Combined wall foundations 
3. Waffle slabs
4. Pour strips
5. Single frames and beams using the Strip Wizard. Refer to the RAM Concept Manual chapters "Using Strip Wizard" and "Strip Wizard Tutorial."

What RAM Concept Can Design with Limitations

The following have been analyzed and designed using RAM Concept. Specific limitations and other notes are

1. Retaining Walls.  While RAM Concept is not optimized for this use, it can perform most of the analysis and design tasks if you are very careful. Care must be used as RAM Concept assumes that gravity loads are in the downward Z direction. You need to set all of the self-dead loading load factors to zero and create your own self-weight loadings. You probably want to apply these loads at the mid-slab depth; otherwise the eccentricity will add a self-weight moment to the slab. While RAM Concept's design cross section reports all of the moments and forces on the design cross section, RAM Concept does not perform design considering all of the forces and moments. Specifically, RAM Concept does not consider the Mz value in design, because RAM Concept does not specify the positioning of reinforcement that is important for Mz design. RAM Concept does not consider “P-Delta” effects.
2. Slabs on Ground.  The expression “slab-on-ground” is often used to described residential house slabs. These slabs can be analyzed and designed as spring supported mat slabs. However, the designer should use engineering judgment to determine if mat analysis and design techniques are suitable for such structures.

What RAM Concept Cannot Design

RAM Concept cannot design the following:

1. Sloping or tapering slabs. Stepping slabs can be modeled. However, each slab and beam is a level member of a single thickness.
2. Pan joist systems. Pan joists can be modeled and analyzed as T-beams. However, there is not a way to model tapered stems and code specific provisions for repeated joists (e.g. reduced shear requirements ACI 318-11 8.13.8) are not considered.
3. Deep beams. The analysis assumes that "plane sections remain plane," which typically does not apply to deep beams. Code specific provisions for deep beams, such as ACI 318-11 10.7 and 11.7) are not considered.
4. Beams of seismic moment frames. The seismic provisions in ACI 318 Chapter 21 are not implemented in the program.
5. Voided slab systems, like bubble deck. 

Is there a limit on the size of structure modeled?

The only limit is the performance of the computer hardware. The analysis run time is approximately proportional to the square of the number of nodes in the model, so large structures may take a significant amount of time to analyze. Design time is approximately proportional to the number of span segment strip cross sections. The RAM Concept manual contains a section “Decreasing calculation time” that contains more detailed information on this topic.

Is there any restriction to the maximum thickness of slab that can be modeled?

RAM Concept's analysis of slab elements considers shear deformation as well as bending deformation. This ensures that RAM Concept gives reasonable results for both thin slabs and thick slabs. In general, RAM Concept's design provisions apply the code requirements that are appropriate for slabs with typical span-to-depth ratios. If the geometry of your slab is outside the usual ranges (e.g. a thick grade beam), you may need to consider if any special design considerations are necessary.

Can RAM Concept design more than one story at a time?

Not by itself. You can use the RAM Structural System to integrate numerous floors into one large model.

See Also

RAM Concept Structure FAQ

Structural Product TechNotes And FAQs