While users of Bentley Structural Analysis software products generally have the option to purchase perpetual licenses of STAAD and RAM software without maintenance, there are specific products and features that require an account to be on Bentley's SELECT program, or a program in which SELECT benefits are included (such as ELS or E365). These situations are detailed below.

Structural WorkSuite

Accounts that own Structural WorkSuite perpetual licenses must subscribe to Bentley’s SELECT program and have each license covered by a SELECT subscription. Use of Structural WorkSuite as a node-locked license is not permitted. If an account chooses to drop their SELECT subscription for Structural WorkSuite, they must relinquish Structural WorkSuite and move to perpetual licenses of the standalone products. In doing so, the account may choose any standalone perpetual license portfolio (only products within Structural WorkSuite) such that the total license value does not exceed the total license value of their previous Structural WorkSuite portfolio. This will generally lead to significantly less product access than Structural WorkSuite.

An account that owns Structural WorkSuite is not permitted to own perpetual licenses of the standalone products that are included within Structural Enterprise. For example, an account that owns ten Structural WorkSuite perpetual licenses is not permitted to also own a perpetual license of STAAD.Pro, since STAAD.Pro is one of the products included in Structural Enterprise. Any term license usage of Structural Analysis products by accounts that own Structural WorkSuite will be processed and billed as a Structural Enterprise term license rather than a term license of stand alone licenses. Accounts that own standalone perpetual licenses of STAAD and RAM may upgrade to Structural WorkSuite, using the license value of the standalone products as credit towards Structural WorkSuite.

STAAD Features Available only to SELECT Subscribers

As of January 2019, STAAD products now contain specific features available only to accounts that have their licenses covered by a SELECT subscription or the ELS program. This started with the STAAD.Pro CONNECT Edition V22 release. These features are referred to as Structural SELECT Entitlements, which is shown in the STAAD.Pro licensing dialog. There are two features in V22 that are SELECT Entitlements:

• Steel Autodrafter
• Building Planner (previously known as STAAD PlanWin)

Accounts using STAAD.Pro through a node-locked license will receive an error message when they attempt to access these features. Certain new STAAD and RAM features in future releases may be offered as a SELECT-only entitlement.

Overview

The purpose of this tech note is to outline the implementation of the ACI slenderness methods for the design of frame and gravity columns in RAM Concrete.

Slenderness requirements for concrete columns are addressed in Section 10.10 of ACI 318-08 and ACI 318-11. ACI 318 outlines three methods to account for slenderness effects:

1. Nonlinear second-order analysis (Section 10.10.3)
2. Elastic second-order analysis (Section 10.10.4)
3. Moment magnification procedure (Section 10.10.5)
   

 A nonlinear second order analysis must consider geometric and material nonlinearities. This type of analysis cannot be performed in RAM Structural System.

The P-Delta method in RAM Frame is an elastic second-order analysis. However, the RAM Frame results can only be used to design frame members; these results are not available to design gravity members. There is an option in RAM Frame to include gravity members under two-way decks in the analysis; however, there is not a way to use these forces for design in RAM Concrete. Also, the P-Delta method in RAM Frame does not include P-delta effects (second-order effects associated with deflections along the member length), which are required by ACI 318-11 10.10.2.2.

The moment magnification procedure is used to design gravity members. The forces used to design gravity columns are taken from RAM Concrete, which does not include P-Delta effects. ACI 318-11 10.10.7 outlines a moment magnification procedure for sway members. An important program defect associated with this procedure was resolved in v15.09.00.

More information on the analysis assumptions in each module can be found here.

There are four possible design categories for concrete columns:

1. Gravity Column, Braced
2. Gravity Column, Sway
3. Frame Column, Braced
4. Frame Column, Sway 

Analysis and design notes for each of these groups are summarized in the following sections.

Gravity Column, Braced

These columns are designed using RAM Concrete Analysis forces. The design forces are calculated using the non-sway moment magnification procedure. The forces reported in the Column Design Report are the magnified forces and not the forces from the analysis.

Gravity Column, Sway

These columns are designed using RAM Concrete Analysis forces. The program assumes that the forces for sway columns are from an elastic second-order analysis. The program does not adjust these using the moment magnification procedure for sway frames. This follows from earlier editions of the ACI code, which allowed for the magnified sway moment to be taken from an elastic second order analysis (see ACI 318-05 10.3.4.1). This is a problem since a P-Delta analysis is not completed in RAM Concrete and RAM Frame results are not available for these columns.

Gravity concrete columns should never be designated as sway columns in RAM Concrete. Instead, these columns should be converted to frame members so that they are included in the RAM Frame Analysis. ACI 318-11 10.10.5.1 permits columns to be assumed non-sway if the increase in column end moment due to second-order effects does not exceed 5%. Gravity, sway column would only occur in structures with significant overturning under gravity load, which would be rare. In future versions of the program, it will not be possible to designate gravity columns as sway columns.

Frame Column, Braced

These columns are designed using lateral forces from the RAM Frame Analysis and gravity forces from either RAM Concrete or RAM Frame (see option in RAM Concrete Column – Criteria – Column Design – Design Checks/Forces tab). The design forces are calculated using the non-sway moment magnification procedure. The forces reported in the Column Design Report are the magnified forces and not the forces from the analysis. Since the moment magnification accounts for both P-Delta and P-delta effects, P-Delta can be turned off in RAM Frame.

Frame Column, Sway

These columns are designed using lateral forces from the RAM Frame Analysis and gravity forces from either RAM Concrete or RAM Frame (see option in RAM Concrete Column – Criteria – Column Design – Design Checks/Forces tab).

The design procedure follows the moment magnification procedure for sway frames in ACI 318-05 10.13. The equation for the magnified end moments is M =  Mns + Delta_Sway*Ms, where

M = total magnified end moment

Mns = non-sway moment

Delta_Sway = sway moment magnifier

Ms = sway moment

In previous versions, ACI 318 permitted magnified sway moments (Delta_Sway*Ms) to be determined from an elastic, second order analysis (see ACI 318-05 10.13.4.1). This is the assumption that is used in RAM Concrete, and a sway moment magnifier of 1 is assumed. Due to this assumption, P-Delta should always be included in the RAM Frame Analysis.

The non-sway moments are the gravity moments, which are taken from RAM Frame or RAM Concrete. In the ACI equation above, the non-sway moments are not magnified. If the option to use gravity forces from RAM Frame is used, the analyzed gravity load cases would include second-order effects from the P-Delta analysis. In most cases, the story displacements associated with the gravity load forces are small, so the increase in forces due to P-Delta effects should also be small. If there is a concern about using an amplified non-sway moment due to P-Delta effects, then gravity forces from the RAM Concrete analysis should be used to design the columns.

For slender columns with high axial loads, the maximum moment may be between the ends of the column and P-delta effects can be important. For this reason, the ACI 318-05 and earlier separated columns for which the slenderness (lu/r) was greater than 35/sqrt(Pu/f’c/Ag). When this threshold was exceeded, the program calculated from the following equation (see ACI 318-05 10.13.5)

M = Delta_NonSway*(Mns + Delta_sway*Ms)

This provision was removed in ACI 318-08.

In ACI 318-08 and later, the sway moments are required to be determined from one of the three slenderness methods (nonlinear second-order, elastic second-order, or moment magnification) for any slenderness ratio. As noted previously, the program is not equipped to run a nonlinear second-order analysis, the elastic second-order analysis does not include P-delta effects, and the sway moment magnification procedure is not implemented. The best the program can do is to combine the elastic second-order analysis with the moment magnification procedure using the same design procedure that is used when the ACI 318-05 is selected.

ACI 318-08 and 318-11 10.10.2.2 requires second-order effects along the length of the member to be considered when the member is slender. Since P-delta effects are not included in RAM Frame, the program should apply 10.10.6 to slender, sway columns. This is not currently done by the program. This is logged as Defect #215527 in our database.

Other Notes

• ACI 318-05 limited kl/r to 100 unless a non-linear, second-order analysis was used. This provision was removed in ACI 318-08 but was still enforced in RAM Concrete when ACI 318-08 or ACI 318-11 is used. Defect #215695 was filed for this issue, and it was corrected in v15.09.00.

• RAM Concrete does not check ACI 318-11 10.10.2.1: total moment including second-order effects shall not exceed 1.4 times the moment due to first-order effects. Defect #215527 has been filed with the development team.

• RAM Concrete does not calculate Q ACI 318-11 10.10.5.2 (Eq 10-10). Enhancement #275537 has been filed .with the development team.

• RAM Concrete does not include an option for using the moment magnification procedure for sway columns. Enhancement #215521 has been filed with the development team.

• ACI 318-05 10.12.3.1 included a lower bound of 0.4 for the parameter Cm. This lower bound was removed in ACI 318-08 but was still enforced in RAM Concrete when ACI 318-08 or 318-11 was used. Deflect #214767 filed for this issue, and it was corrected in v15.09.00.

• Slenderness effects are not included in RAM Concrete Shear Wall.

See Also

Concrete Column Minimum Eccentric Moment

Ram Structural System Support Solutions

• 1. Can RCDC design Curved beams? Will it convert the curved beam composed of many parts to a single physical beam?
  • Yes. If curved beam is modelled in sufficient small parts then RCDC identifies it as single beam as per the geometry and support conditions. The beam is designed for Bending, shear and torsion as per regular beam.

• 2. Can RCDC provide bottom bar without curtailment in single span?
  • RCDC has the option of detailing bottom reinforcement as Best fit and Max dia. user can use option of Max diameter to maintain the same number of bars at bottom most layer. For Best fit it curtails the bars at support if it is allowed as per detailing requirements.

• 3.Can number of bars for the given width of beam be edited?
  • Yes, User can set the number of bars as per width of section in "zone bar setting" option. It also checks the minimum and maximum spacing criteria at the same time. For more information refer Topic “Preferred Bar Spacing” for beam from help Content.

• 4.Can RCDC provide the detailing of beam with lowest diameter throughout the length and balance area of steel with higher diameter in other layer?
  • Yes. It can handle this only for top reinforcement. To maintain the lowest bar at top user can select “min dia.” option in general setting. Lowest Bar diameter and numbers will be provided across the length of the beam and remainder will be provided at next layer of reinforcement. This option will result in detailing like 2-T12 at first layer and 2-T25 at second layer. For more information refer Topic “General and Reinforcement Settings” for beam from help Content.

• 5.Does RCDC allow to provide only 2 bars for top reinforcement?
  • The Number of Bars suggested by RCDC are as per beam width and maximum spacing criteria given in codes. User can change the numbers of bars prior to design subjected to spacing criteria given in code. For zero bending moment zone RCDC can provide minimum two bars with minimum bar diameter. For more information refer Topic “Preferred Bar Spacing” for beam from help Content.

• 6. What is the purpose of mirror & straight option in group/ungroup tab?
  • Mirror grouping option can be used if beams are mirror in arrangement with same geometrical properties. So beam on one side can be mirror in detailing of the beam on other side. Similarly if beams are identical in plan i.e. beam geometry is similar at a given level and repetitive then these beams can be grouped. For more information refer Topic “In Plan Grouping” for beam from help Content.

• 7. Why specifically only 13 stations (for beams) can be imported from E-tabs to RCDC?
  • 13 stations divides the element in to twelve parts. As per standard practice of all codes, curtailments of reinforcement lies at L/4, L/6 and L/3 of span where L is the span of the element. Dividing the element in to 13 station satisfies all the requirements of curtailments. Curtailment of reinforcement helps in beam detailing thus it is mandatory to provide 13 stations to all beams in the analysis. Staad automatically provides the results at 13 stations. E-tabs can provide results at any stations as per user requirements Thus in E-tabs user has to assign output stations as 13 before exporting the results. For more information refer topic “Technical Discussion” of beam and Column from help Content.

• 8. Side face reinforcement (SFR) is designed for beams even though the depth is less than 750mm, whether there are any options to enable/ disable side face reinforcement?
  • In RCDC, SFR is calculated as per design requirements including torsion. User can provide the SFR even it is not required in design. In many cases for beams with depth less than 750 mm, there may be torsion, which would result in SFR. User may check the detailed calculation report for clarification.

• 9. Please give clarification of failure type for beam element. Failure type – Shear –Tc max
  • Tc max failure means Tv exceeds the maximum permissible shear stress.

• 10. Even after opting best fit for top reinforcement, why does RCDC provides higher reinforcement (as per minimum Pt) at top at mid-span?
  • This would be typically doubly reinforced section which causes more reinforcement at top even when moment at that location is nominal. In the calculation report it can be clearly checked where Asc-required at mid-span is captured. This is the top reinforcement required at that section.

• 11. Why default 0.2% is provided for nominal steel in RCDC? Does it have any reference?
  • RCDC provides the nominal steel where bending moment is ZERO. Default value provided in RCDC for nominal steel is 0.2 %. This is an approximate Value and we have kept the value close to minimum steel in beam. The above value is editable and can be put as per user requirements. For zone with no Bending Moment, RCDC uses nominal steel and for detailing, it would adopt 2 bars with minimum diameter possible.

• 12. Is there any option to disregard the contribution of concrete in resisting shear for beam when IS: 13920 is used?
  • No. Beam shear design is as per IS 456. Shear induced due to Sway action is calculated as per IS 13920. For Sway shear also the part of shear is arrived from the dead and live load. Thus RCDC does not allow to ignore the concrete for shear design.

• 13. When IS: 13920 is selected, does RCDC consider required rebar or provided rebar to calculate capacity (plastic) shear force (or moment capacity) for beam?
  • Yes. RCDC designs the beam shear as per Clause 6.3.3 of IS 13920 and consider the reinforcement provided to calculate the moment capacity. For more information refer Topic “Calculation of Ductile Shear” for beam from help Content.

• 14. Does RCDC calculates moment capacity for sway shear calculations as per rectangular section or flanged section for beam?
  • For moment capacity of section RCDC always considered as a Rectangular section as Flange section is not applicable at support. Also to get the flange action, flange has to at compression side which is not the case at support. For more information refer Topic “Flanged Beam” for beam from help Content.

• 15. If Beam is designed for axial plus biaxial forces, ideally if axial force in beam is less than the permissible value given in IS 13920 code, the member should be designed as beam only both for strength and crack width and check as per columns should not be applicable.
  • Whenever design for ‘Biaxial Bending’ is selected, RCDC would treat the design of beam like a column. There is possibility where axial forces would be negligible but lateral moment and shear would be high. In this case this member should be designed as a column only. Axial forces will not govern whether to details the member like beam or column.IS 13920 suggest to design/ details member like column as per clause 7 if axial stress exceeds 0.08ck. here the section will be detail as a column. shear (ductile) links should be calculated as per column.if axial stress less than 0.08 fck the section would be details as beam. All the links calculations would be as per beam. Further depending on Pu-threshold value set by user (the value is considered as compressive), RCDC will design the section with Pu, Mu-major and Mu-minor. If Pu for a given combination is less than Pu-threshold, it simply assumed.Pu = 0. This is only for ‘design combinations’ or limit state of collapse.For crack-width, there is no input for threshold value (currently there is no provision for it) of axial force. The crack-width is checked for service combinations. In this case, the values as per combinations are used for crack-width check.

• 16. We accept that concrete capacity shall be ignored as per clause 6.3.4 of IS 13920-2016 but this can be logically ok if only Ductile shear governs the design.In cases where DL+LL shear governs the design (i.e. no plastic hinge evidently formed) it will be very conservative to ignore shear capacity of concrete in beam.
  • The requirement of ignoring concrete capacity is due to unpredicted forces during earthquake. The earthquake forces are instantaneous, the concrete will crack, and plastic hinge will be formed. Even after the earthquake loads, the beams will be loaded with the Dead and live loads. The cracking of concrete, the shear capacity of the bean will be depending on the shear reinforcements only. Thus, ignoring concrete capacity of the beam for shear check is applicable to all load combinations. So even the critical combination is DL+LL, the concrete capacity should be ignored

• 17. In Beam design output of stirrups, what is 2L-T8 (H)?

  • 2L-T8 (H) is the horizontal link (stirrups) provided in the beam in case if Beam is designed for Axial+ Biaxial forces.

    Based on the axial stress (0.08 fck) type of beam detailing is performed in RCDC. If section selected for Axial + Biaxial design in RCDC then section will be designed as a column. If the section requires stirrups for horizontal shear in case of beam detailing, RCDC provides horizontal links. In case of section is detail as a column, RCDC provides the horizontal link to tie all the rebars along all faces of the section.

• 18. If the Beams exists at support level of the structure, can it be design in RCDC?
  • Yes. if the Beams are present at support level, RCDC can read and design these beams. After reading the analysis file for beams, RCDC shows all the levels available in analysis file. User can select the support level for beam design. Column above the support level are considered as support for beam and accordingly beam drawings are generated.

• 19. Three beams are failed due to shear since no links were designed and also, I am not able to add in any by manual means.

  • If the beam shown failure due to stress exceeds the maximum permissible stress for Shear and Torsion, then it’s a section failure. User can increase the size or Material grade to pass the beam in design. As it is section failure, there is no option available to change the reinforcement diameter to pass the design.

• 20. While designing beams of a group a floor together for a multi-story building, the software error. There is no problem if I design for each floor level separately.
  • There are some missing beams marked in snap below. Please note that the levels can be grouped only if the beam arrangement is similar at all floors.As RCDC is design and detailing software, it generates the Beam elevation. If the Beam are not same at all grouped levels, then it would not be possible to perform the beam design and generate the design calculation reports including drawings.

• 21. It is noticed that when ductile design is done (even only near supports), that there is a big jump in shears in the “Mid” span.  Let me know if this is unexpected

               Reply:

              For Non ductile and Ductile beam, Shear force at end is depend on the following settings,

              .

As per above settings, for ductile beam the end shear would be considered as per 2xDepth of beam. For Non ductile it would be L/3. It is purely depend on the depth of the beam and length of the Beam. If the Beam L/3 is more than the 2xD then it is possible that  at mid zones shear would be less as compared to ductile beam.

RCDC provides following two options for Sway shear check in Beam design.

For Ductile Shear at Support      : Sway shear would be calculated only at ends.

For At All Station                           : Sway shear would be calculated at all 13 stations for which beam is designed. Maximum of Shear due to sway at mid zones would be considered as critical in design.

It is not clearly mentioned in the IS code up to which location the sway shear is to be considered. The Option is added as per our discussion with the IIT professors. Professors is in opinion that, Earthquake loads are impact loads and shear due to Lateral loads might extend up to the mid span of beam. To avoid this kind on un-foreseen condition he has suggested us to add the option of checking sway shear at all stations.  Thus, these two options are available in RCDC. But It would be user’s choice

22.How to calculate reinforcement of beam at face of column in RCDC?

In STAAD generally we design the beam as centre to centre of column and from output we interpolate the beam reinforcement at the face of the column. How we can do the same in the RCDC. Because in boiler supporting structure where column size is 900x900 mm difference in beam reinforcement at centre of column & at face of the column is around 1000 mm².  Like in attached STAAD file for beam member no. 105, reinf. At centre of column is 3297 mm². Whereas by interpolation at face of the column its around 2722 mm².

Reply :

RCDC design the Beam based on geometry and forces available from the analysis file. It doesn’t modify the forces. In you case, the beams are modelled up to centre of the column and beam need to design at face of the column.

We would suggest following methods to add the beam at face of the column, so that beam will get design at moment available at face of the column,

User can assign Member offset command available in STAAD. RCDC will read the beam length and force available in STAAD as per the offset beam length.

User can define the rigid member within the column extent. The property of this member can such that the stiffness is more than the beam stiffness. i.e. YD = 3m and ZD = 0.45 m

The density of this member can be assigned as Zero. RCDC auto ignores the member within the column and with zero density.

The beam can be designed as per moment available at face of the column. Refer below snap

Below is the snap from the RCDC,

• 23.The Building is designed including EQ loads and STAAD RCDC is giving more reinforcement at bottom near supports as curtailed bars. Why?
  • RCDC design the beams as per section forces available from analysis. it designs the beams at 13 stations for given load combinations. when lateral loads are applied, due to sway effect end moment exists at end of the beam. So generally for +ve Eq and -ve Eq loads, the heavy moment exists at top or bottom of the end of the beam. we would request you to check the detailed design calculation report to get more information about the design of the beam. You will get the information about the for which moment end reinforcement is calculated.

• 24. I showed best fit beam reinforcement drawings to client, but he categorically said that I have never seen this type of detailing and it’s not practically possible. Why RCDC gives this type of detailing? 
  • Best fit detailing option is used by most of the structural consultant in Metro cities. it is generally used for the commercial, office and shopping malls where beam spans are larger. Best fit option can be used to save the reinforcement for long span beams. there are other options available in RCDC. i.e. Maximum Dia & Min. Dia which gives flexibility to users to detail the beams as per design and detailing requirements. Beams having shorter spans, maximum or minimum diameter option can be used to avoid lapping.

• 25. STAAD adv. Concrete designer RCDC provides top bars with lapping in output beam reinf. near supports but I want through bars at top without lapping and with curtailed bars near supports. How to do it?
  • Please select Min OR Max diameter detailing option in design settings in RCDC. refer below snap,
    
    

26.Can you provide clarification regarding the curtailment of 100% top reinforcement at a certain location from column as per IS code?

Reply:

RCDC design the reinforcement as per the forces available at all sections in the beam. It takes 13 stations (i.e. 12 zones) for design of beams. Based on the forces available in each zone, reinforcement is calculated. Lapping locations are available as per user inputs. Default location for lapping of top reinforcement is L/4. As RCDC design the beam for 12 zones, the options of L/3,L/4 and L/6 are available for lapping at top and bottom reinforcement.  User can change the lapping location as per design requirements.

Lapping of top reinforcement is available to optimized the reinforcement. Curtailment location is available in SP 34. Refer below snap,. As far are rebar are lapped with the development length, lapping is permitted for top reinforcement.

RCDC provided various option for top and bottom reinforcement detailing. This option is available in General and reinforcement settings,

If user doesn’t want to provide lapping for top reinforcement, we would suggest you to use Max Dia and Min Dia option of detailing.

27.In BBS for ductile beams, there should be no lap splice within the joint and within 2D from the face of the column. (ACI 318M – 14 cl. 18.6.3.3)

(Currently, lap splices are still drawn within the restricted locations.)

Reply:

RCDC design the reinforcement as per the forces available at all sections in the beam. It takes 13 stations (i.e. 12 zones) for design of beams. Based on the forces available in each zone, reinforcement is calculated. Lapping locations are available as per user inputs. Default location for lapping of top reinforcement is L/4. As RCDC design the beam for 12 zones, the options of L/3,L/4 and L/6 are available for lapping at top and bottom reinforcement

At top location, the lapping is provided at curtailment locations. i.e. L/3,L/4 or L/6 distance from column face. Here the distance 2xD is not checked for curtailment. If we start providing curtailments for beams as per the beam depth, it would be complicated. The curtailment location will vary as per the beam depth. The location of curtailments might fall between two stations. Checking reinforcement curtailments at any location as per 2D would not be simple and might not give the desire result. Interpolation of forces is not possible for in between values. Even if we consider on higher side, it would not be consistent to all beams and curtailments will not match the distance 2D for all beams. Also, it is very difficult to handle Ast calculations and shear check location for individual beams.

For Bottom location, RCDC provides the lapping at face of the beam. The higher diameter rebars extends to lower diameter to make sure that the it satisfies the bending and shear check criteria. Also, the confining of the reinforcement exists up to twice the distance from the column face.

If we provide lapping away from the twice the beam depth, it might reach in the middle zone of the beam which is also needs to avoid as it is governed by permanent loads. In this case we might need to handle ductile and Non-ductile beams separately. For ductile beam lapping will place away from the 2D and for Non-ductile it is possible to provide within 2D.

For such cases, we would recommend user to use detailing options available in RCDC.

For Top rebars use max dia. Option: here the same diameter rebar is continued at outer most layer to avoid lapping.

For Bottom rebars use max dia. Option and try to provide same rebar numbers and diameter to adjacent beams to avoid lapping.

28. Does RCDC perform the Serviceability check for allowable deflections from ACI 318M-14 Table 24.2.2 by using the effective moment of inertia from ACI 318M-14 cl. 24.2.3.5 ?

Reply:

Presently deflection values are not read by RCDC and deflection check is not performed. There would be simple check for deflection as per the deflection values available from analysis for given load cases. This would-be short-term deflection check.

Other is long term deflection check which is depend on the creep and shrinkage of concrete.

 We will try and take this as an enhancement in RCD for future release.

• 1. Can RCDC handle columns of shape L, T and other odd shapes?
  • Yes. RCDC can design any shape of column like L, T, I, E, Capsule and polygons up to 12 edges. It also has an option to create user defined sections. For more information refer Topic “Irregular Shaped Column” for column from help Content.

• 2. When equal number of bars are provided in all columns from plinth to top floors. After design it’s showing lesser bars at the bottom and more at top.
  • RCDC designs the column floor-wise. If percentage reinforcement required at a given level is more than the lower floor then it could be because of higher moment at that floor. Normally this happens at terrace floor where moments are more as compared to lower floors. This can be checked as per efficiency ratios in the design table.

• 3. Some of the columns are missing at lower level even if they have exist in Staad model.
  • If the model has column members with no joints at in between levels, then these columns will appear ‘Missing’ in those levels. This can be checked by generating column elevation.

• 4. Forces for column do not match with analysis.
  • RCDC reads the forces only for Primary load cases. These will match with the analysis forces. The forces for combinations are computed within RCDC as per load factors and other conditions like (LLR) Live load reduction. If the conditions of LLR are matched in analysis and RCDC, the design forces will match. For foundation design, RCDC uses member forces and not support reactions. In case of rotated columns or columns with offset, the support reactions do not match with member forces.

• 5. In edit link arrangement all the internal links can be removed. It doesn’t affect the design of links in column design. Please clarify.
  • Option of Edit link arrangement is provided to change the link arrangement. It is provided only as detailing tool and not linked to design. User is expected to check the shear requirements before modifying it. Also it may be noted that, diameter and spacing of links is not recalculated after editing of links. For more information refer Topic “Edit Link Arrangement” for column from help Content.

• 6. Does RCDC calculate the Effective length factor automatically or it is user defined? Is it same for all columns in model or different?
  • RCDC identifies the sway or Non-sway frames factor as per storey stiffness and storey index. It calculates relative stiffness of the beams and columns as per column orientation. It calculates the effective length factors as per available charts for Sway and Non-sway. Effective length factor would be different for all columns as per calculations. Option of overriding effective factor is available to user. User also can apply single factor to all columns on one click. For more information refer Topic “Effective Length Factor” for column from help Content.

• 7. Does RCDC designs shear wall for out of plane moments in addition to in plane moments?
  • RCDC designs the sections as per the forces from analysis. In addition to the forces from analysis, RCDC calculates moments due to minimum eccentricity in both major and minor directions and performs section design. If applicable, slenderness moments are added in the final design moments. For cross-section design of walls same principles as column design are followed.

• 8. Can we design shear wall/wall with single layer (mesh) of reinforcement?
  • No. Shear wall design with single mesh is not available as it is designed for the axial force and biaxial moments.

• 9. RCDC uses the formula of column for the “Minimum Eccentricity Calculation” (in IS code), though it is different for shear walls as per Clause: 32.2.2 of IS 456-2000.
  • Clause 32.2 in IS 456-2000, is for Empirical Design Method of walls. Clause 32.3 is for design of walls subjected to horizontal and vertical loads and same has been followed in design of wall in RCDC.

• 10. Please clarify the braced and un-braced design conditions.
  • These are design principles chosen by structural engineer for design of buildings. These are beyond purview of RCDC. RCDC captures this as information for further calculations.

    As per clause 39.7.1 (Notes), IS code allows user to design column based on Braced and Un-braced conditions. The end moments are calculated based on end conditions given in this clause.

    In Euro code, the braced and Unbraced option is available for calculation of effective length factor.

• 11. Lateral ties diameter, spacing & no. of columns main bars are correlated by formula given in IS: 13920 for rectangular and circular column. Can any single parameter be provided to calculate remaining two parameters in RCDC, once the initial design is complete?
  • Yes. After initial design is completed, user can change the numbers and diameter of main reinforcement in redesign option. Diameter and spacing of links can be changed. For any parameter changed in redesign process, RCDC would design/ check the column with all relevant clauses. For more information refer “Edit Local Column Design” from help Content.

• 12. Pl refer to Annexure A off IS 13920 which states walls are to be designed for uniaxial bending. Columns are considered as biaxial. Hence, their design cannot be clubbed under one set.
  • Annex A of IS 13920 is about the calculation of moment of resistance of the web portion of rectangular wall section. This is further used only in calculation of effective axial force in boundary element due to major axis moment. It may please also be noted in IS 456 which is the main code for design there is no separate procedure for design of walls. Clause no 39.6 of IS 456 refers to members subjected combined axial and biaxial bending which includes column and walls. Thus for biaxial design RCDC follows the basic principle of plotting P-M curve for design and checks for boundary element using annex-A provided in IS 13920. For more information refer Topic “Technical discussion” for column from help Content.

• 13. Can we have calculations for boundary zone length in wall design?
  • Boundary elements are provided for ductile walls as per IS 13920. Governing Criteria to provide Boundary element is if stress is more than 0.2*fck and Boundary wall terminates (along the height of wall) if stress is less than 0.15fck. Zoning of reinforcement is done around the boundary element. The initial length of the boundary element is arrived at as per procedure discussed in help. For more information refer Topic “Technical discussion” for column from help Content.

• 14. RCDC follows ductile detailing as per 13920 for outer ring of boundary element but reduces link dia. & spacing for inner links.
  • As per ductile detailing, for the calculation of confining links (outer links in BE – BE main) of boundary zone, formulation of Ash as per IS 13920, clause 7.4.8 is used. The internal links (BE others) are provided at same spacing with lowest possible diameter to maintain the “h” value in calculation of Ash. At middle zone, the links are provided as per IS 456. As a standard practice RCDC provided links to all longitudinal reinforcement.

• 15. What is the basis for only 20% of vertical reinforcement is considered for the calculation of Shear capacity (Tc)?
  • Based on the IS 456, Only tension reinforcement is to be considered for shear capacity (Tc) calculation. We can assume at- least 30 to 40% reinforcement would be under tension in a given load combinations.  Also, the effective depth as per code is suggested to be considered as 0.8 x the total depth for the shear calculation. Considering both the criteria, it is assumed that the only 20% of the main reinforcement of entire wall would be in tension.  It is also very difficult to identify the % tension reinforcement in wall for combination which is critical in shear. This has been discussed with the professor on the code panel in technical presentation of IS 13920-2016 and suggested to use only 20%of the main reinforcement in the shear calculation.

• 16. How and when Modulus of rupture check performed in RCDC?
  • Modulus of rupture check is performed as per clause 6.2.2 of IS 456-2002. The option of performing this check is available in RCDC as per user’s choice. This check is performed only for the tensile axial force in the column against the tensile capacity of the column. Effect of moment is not considered as this check is for tensile strength of concrete. If the axial tension is more than 0.7xsqrt(fck) then RCDC shows the column failure. It is just a check performed in the RCDC, there is no impact on the final design of the column.

• 17. In which cases we should not consider perform slenderness check - When to and when not to consider slenderness?

  • Slenderness check is an option given in RCDC. If the structure is analyzed with the Non-linear load cases (P-Delta) it is not recommended to consider this check. If the structure is analyzed with linear load cases, it is recommended to consider this check. If this check is selected, slenderness check will be performed, and additional slenderness moments will be calculated if column is slender.If this check is not selected, slenderness check will not be performed.

• 18. Provide detailed explanation for identification of section as a wall with respect to Depth and Width of member in RCDC

  • Please note the points below followed in RCDC for design of Columns based on provisions of IS 13920 (2016). This is as per our understanding of the code and based on discussions with some experts on the code –

    1. Columns should be B/D >= 0.4 (or D/B <= 2.5 – clause 7.1.2)
    2. Columns with as B/D < 0.4 to be designed as per provisions of wall (Clause 7.1.2)
    3. Walls to be considered if D/B > 4 (Or B/D <= 0.25) (Clause 10.1.3)
    4. As per experts, 2.5 < D/B < 4 should be avoided as these elements exhibit partial wall-column behaviour
    You would notice that, in RCDC we allow users a bit of flexibility in defining the ratio for differentiation of wall and column. By default, the value is set at 4 as per the provisions of code. We hope this explains, the reason for defining the section to qualify as wall. For example, if you want sections with D/B > 5 to be designed as column. So, in RCDC, you have to set the qualifier for this as 6. This will segregate the cross-sections in 2 categories – 1) All sections with D/B <=6 would be treated as columns, 2) All sections with D/B > 6 would be treated as walls. You would appreciate that; we would not be able to provide this option to be changed for individual member. It would not be possible for us to handle that.

• 19. Provide detailed explanation for Gravity column design in RCDC.

  • Gravity columns is a choice that you as structural engineer have to make in your system. To reflect this correctly in analysis, ideally these columns should not participate in lateral load resistance in carrying shear and bending moments. These should be defined as ‘pinned’ ends in lateral load analysis. As per current limitations in E-tabs and STAAD, this is not easily manageable. Hence, we have allowed the users to select the required columns in RCDC and treat them as ‘Gravity’ columns. RAM software has the option to analyse the structure with combination of Lateral and Gravity columns.

    As per code, the Gravity columns should be designed for the forces from analysis as well as effects of lateral displacement (known as ‘displacement compatibility’). This is done by considering moment due to Pu (Axial load from Gravity load combinations with DL +LL) acting at R*Delta distance away (Delta is displacement due to lateral loads). We would request you to go through Clause 11 of IS 13920 (2016) for more details on this.

    In RCDC, we follow the above procedure in detail. Please check detailed design calculation report for Gravity columns for more information.

    Please note that, in RCDC the member can be defined as ‘Gravity column’ only if that qualifies as column based on D/B ratio. Walls can’t be design as Gravity members. It can be either Non-ductile or Ductile. Further, the Gravity columns are designed for Vertical gravity loads with effect of later displacement due to lateral loads as explained earlier. Click on below link to understand the implementation of Gravity column in RCDC.

    https://communities.bentley.com/products/ram-staad/m/structural_analysis_and_design_gallery/274370

• 20.Why only 50% of longitudinal reinforcement considered For Column Shear Calculation?
  • for column shear calculation, Tc shall be calculated for tension reinforcement. As column is mainly axial force carrying member, all the rebar would not be in tension. Also, when column is designed, rebars below the neutral axis are in tension. For shear check, identifying rebars those are in tension for combination which is critical in shear would be critical. Thus, RCDC assumes the 50% of the tension reinforcement for shear calculation

• 21. Why RCDC shows message of “Elevation of Column has been Omitted” while generating elevation of combined wall?

  • Combined walls are consisting of more than one walls. If the wall shape and size is same at all floors, RCDC generally generates the elevation of combined wall showing one face only.

    If the wall shape and size is not same throughout the height of all floors, it is difficult to generate elevation of these walls. The combined junctions of walls are detailed separately to satisfy the percentage reinforcement in both the walls. Also showing elevation of each face of combined wall would be difficult in case of thickness changes, thus RCDC generally ignore or omit the elevation of combined walls for elevation. Cases like major variation of reinforcement along height of wall and if combined wall consist of column are omitted.

    Generally, elevations are generated to show typical reinforcement detailing along the height of column/wall. User can still generate elevation of column and single walls for typical reinforcement details.

• 22.There is option under shear wall for detailing as Boundary Element or Equi Spaced rebar. I wish to have detailing as equi-spaced rebar, but it never gives detailing as equi spaced and redesign consume lot of time

  • When you select the option of “Detail with Equi-spaced rebar arrangement" RCDC design and detail the wall with Zones, however rebar spacing in all zones are maintain same. refer below snap showing rebar arrangement with same setting,

if you unselect "Detail wall with Boundary element" it will design as a ductile wall without Boundary element but it will try to provide zones to optimized the reinforcement.

when you select both the options i.e. Boundary element and Equi-spaced, it will design as Boundary wall with equi-spaced rebar arrangement. This setting is applicable for Non-ductile wall if you want t provide equal spacing.

if you want to design wall as column and with same rebar having equal spacing, then you have to perform the redesign step, however in redesign column tool allows user to change the type from "Zonal" to "Equi" in one step for wall along height. refer below snap,

for wall, RCDC tries to optimize the reinforcement by providing higher diameter at edges.

23.Does RCDC calculate the effective length factor based on ACI 318M -14 Fig. R6.2.5 (b) for sway frames?

Reply:    

Reply: RCDC calculates the column effective length factors as per above charts based on type of frame.

Type of frame is identified as per story height, axial load, relative displacement and story shear. Refer below snap,

Based on the column at top and bottom along with beam stiffness of story considered, value of Ѱ is calculated. Refer below snap,

As per Ѱ, effective length factor (k) is calculated based on fig. 6.2.5

Fundamentals of Analysis and Design for Stability

Webinar Q&A

Webinar Date: January 2016

The recording of this webinar is available at: Fundamentals of Analysis and Design for Stability

The slides from the presentation can be downloaded from here:

http://communities.bentley.com/products/structural/structural_analysis___design/m/structural_analysis_and_design_gallery/271634

Webinar Description

The process of designing for strength and for deflection and drift are generally well understood, but the issue of Stability is less understood and often ignored. What can potentially cause a structure to be unstable? How can those instabilities be discerned and addressed in the design of a structure? In this webinar the fundamentals of Stability, including P-delta, out-of-plumbness, and member imperfections were presented, with an explanation of how Stability or a lack thereof can impact both the member design forces and the structural drift and deflection. Strategies and techniques for addressing stability issues through 1^st- and 2^nd-order analysis, amplification of design forces, and reduction of member capacity are presented. Code requirements related to stability are often obscure and the intent is unclear; several modern building codes and specifications are highlighted and compared, including ASCE 7-10, AISC 360-10 Direct Analysis Method, ACI 318-14, Eurocode EN 1993-1-1:2005, and Australia AS 4100-98. It is shown how RAM Frame and other software can be used to consider and satisfy these stability demands. 

The following questions were submitted during the presentation of the webinar.

Questions and Answers:

Why is it necessary to perform a 2^nd-order analysis? We use a 1^st-order analysis for most common buildings.

Historically it was difficult to include P-delta and the various 2^nd-order effects in the analysis of a structure (that was often done by hand or charts). When the equations for calculating member capacity were established in the various specifications they were calibrated (i.e., generally conservative) to be appropriate for the analyses being performed at the time. The ability to perform more sophisticated analyses has become more accessible through computer automation, so therefore the capacity equations can be made more precise. Recognizing this, the AISC 360 specification committee developed more refined capacity equations based on the assumption that a more sophisticated analysis would be performed to calculate the member forces. This resulted in the development of the requirements for the Direct Analysis Method, which describes in detail what needs to be done with the analysis so that the capacity equations are valid. The Effective Length Method and the First-Order Analysis Method are given in Appendix 7 of AISC 360-10 as acceptable alternatives to the Direct Analysis Method if the P-delta effects are small. This means that the capacity equations of Chapters D through K are only valid if you have performed an acceptable analysis. If the analysis hasn’t accounted for the stability effects, the capacity equations will be unconservative. This is true for all modern steel and concrete design specifications, not just AISC 360.

What quick method you do recommend to determine if P-delta is critical or not? Or should we go straight to performing a P-delta analysis?

For large P-delta (P-D), Appendix 8 of AISC 360-10 gives the method for calculating the B₂ factor, a “multiplier to account for P-D effects”. It is calculated for each story, and is a function of the total vertical load, the story height, the story drift, and the horizontal force that produced that drift. This can be calculated by performing a 1^st-order analysis. If the value of B₂ is 1.0 (or less), P- D is not critical; otherwise B₂ will indicate what impact P-D has. For example, if B2 is 1.2, P-D increases the design forces due to the lateral forces by 20%. Similarly, Appendix 8 gives a method for determining the impact of small P-delta (P-d), with a B₁ factor.

ASCE 7-10 Section 12.8.7 defines a Stability Coefficient, q, for which a value less than 0.10 indicates that the analysis does not need to include P-delta. Although appropriate for other structures, I recommend that this not be used to determine that a P-delta analysis is not necessary for a steel structure; AISC 360 requires that P-delta be considered, and as explained above, the AISC member capacity equations are not valid unless P-delta has been accounted for.

Having said all of this, I recommend that you always include P-delta in your analysis and avoid the effort required to determine if it is significant or not. Most software readily accommodates this.

For analysis of steel structures as per AISC 360-10, should both P-D and P-d effects be considered simultaneously or can any one be done individually?

AISC 360-10 requires that both be considered simultaneously. They can be handled using analysis methods, or the B1 and B2 factors, or a mix of those.

In contrast, Australia AS 4100 gives a simplified approach using the larger of the two, but permits a more detailed approach (similar to AISC 360) using both.

How is the magnitude of B₂ calculated?

B₂ is given by Equation (A-8-6) in Appendix 8 of AISC 360-10. It is calculated for each story; all of the members on a story have the same B₂ value. To calculate this value it is necessary to first perform a 1^st-order analysis on the structure. From that analysis determine the interstory drift, D_H (which is the displacement of the story being considered minus the displacement of the story below). Determine the total vertical load, P_story, imposed on all members, not just those on Frame members. H is the story shear produced by the lateral forces used to compute the drift. From these, B₂ can be calculated.

If required to use both ASCE-7 and AISC, which one governs P-Delta method?

Section 12.8.7 of ASCE 7-10 addresses requirements for P-D and stability. A Stability Coefficient, q, is defined, with limits on what is allowed (q_max). That requirement must be satisfied even if the structure is being designed under AISC requirements. Section 12.8.7 of ASCE 7-10 also gives conditions under which it is not necessary to consider P-D effects. However, AISC 360 always requires that P-D effects be considered, so in my opinion a P-D analysis should always be performed. One could argue, perhaps correctly, that they “considered” P-D by relying on Section 12.8.7 of ASCE 7-10 and determined that it is not necessary to include P-D effects in the design.

Do you need to use K values in addition to a P-Delta Analysis to capture all stability issues?

If your analysis and design conform to the requirements of the Direct Analysis Method given in AISC 360-10 Chapter C (including P-delta, stiffness reduction, notional loads, etc.) or to the requirements of the First-Order Analysis Method given in AISC 360-10 Appendix 7, then you are permitted to use an effective length factor, K, of 1.0, even for moment frames. If you are using the Effective Length Method given in Appendix 7 you must determine and apply the effective length factor, K.

How does the RAM Structural System combine the reduced stiffness due to geometric non-linearity (the Geometric Stiffness Method’s stiffness reduction for P-D) and the residual stresses (Direct Analysis Method’s 0.8 and t_b stiffness reductions)?

The program applies both simultaneously. For example if the Geometric Stiffness Method determined that the stiffness needed to be reduce by a factor of, say, 0.95 for the P-D analysis, the program would reduce the stiffness by multiplying the stiffness by (0.95)(0.8t_b). This is appropriate since each is accounting for different effects that occur simultaneously.

Can response spectrum be combined with the AISC 360 Direct Analysis Method?

Yes, it can, but not all software is capable of doing that. The Direct Analysis Method’s 0.8 and t_b stiffness reduction factors can be applied to the stiffnesses of the members in the response spectrum analysis, and the Notional Loads can be combined with those results if required. The difficult comes in the requirement to consider P-delta. If the software uses an iterative method for P-delta it cannot be included in the response spectrum analysis because an iterative analysis and a response spectrum analysis are incompatible. So if the software performs an iterative analysis for P-delta, the response spectrum results will not include P-delta and will therefore not conform to the requirements of the Direct Analysis Method. On the other hand, as explained in the webinar, the Geometric Stiffness Method for P-delta analysis involves stiffness reductions (instead of iterations) to get to the same result. These stiffness reductions can be applied to the analysis model that is used in the response spectrum analysis, and the result is that the response spectrum analysis results include the P-delta effects.

The recording of a webinar previously presented, A Practical Approach to Using the Response Spectra Analysis Method, is available for viewing free on-demand. It can be found at: 

A Practical Approach to Using the Response Spectra Analysis Method

When using reduced stiffness the analysis model will experience higher deflection so do the final deflection values need to be reduced?

The 0.8 and tb stiffness reduction required for member design by the AISC 360 Direct Analysis Method should not be applied to the analysis model when analyzing for the story drifts. They should only be applied to the analysis model when determining member design forces. This requires two separate analyses. See the Commentary on page 16.1-280 of the AISC Steel Construction Manual 14^th Edition. Also, see the wiki on Bentley Communities titled ASCE 7, AISC 360, and the Direct Analysis Method in the RAM Structural System.

It was written specifically for the RAM Structural System, but the methodology and concepts are applicable regardless of the software used.

In the case of steel frames, lateral bracing contributes to the stability of the structure. How is the software taking account of the imperfections in the connections and the bracing itself?

The nature of connection imperfections is not well documented nor easy to quantify. Consequently it isn’t commonly explicitly modeled in the analysis of most structures. It is usually ignored. If it is felt that for a given condition the effect might be significant, and if the effect of the connection imperfection can be quantified, connection springs can be assigned to the member ends. For the braces themselves, if the Direct Analysis Method is being used, the 0.8 stiffness reduction is applied to the brace stiffness.

How do we calculate first order drift and second order drift?

Drift is the difference between the lateral deflection at one level and that of the level below. For example, if the Third story deflects 1.0” horizontally and the Second story deflects 0.75” horizontally, the Third story drift is 1.0 – 0.75 = 25”. When referring to 1^st-order drift vs. 2^nd-order drift, what is usually meant is the drift without the P-delta effects vs the drift with P-delta effects (since P-delta is usually the largest contributor to the 2^nd-order effects). So to get the 1^st-order drift perform the analysis without the P-delta analysis, and to get the 2^nd order drift perform the analysis with the P-delta analysis.

Can the AISC 360 Direct Analysis Method be used in the concrete columns?

The requirements of the Direct Analysis Method have been calibrated to produce member design forces appropriate for use with the steel member capacities given in Chapters D through K. They would not necessarily be appropriate for the design of concrete members. If a model was a mix of steel and concrete members it would be appropriate however to apply either the stiffness reduction factors or else cracked factors (e.g., Table 6.6.3.1.1(a) of ACI 318-14) to the concrete members for the analysis to determine the design forces used for the design of the steel members. ACI 318 and other concrete codes have their own specific requirements for consideration of stability effects in the analysis used to determine the member forces in the design of concrete members. In a mixed model the analysis used for the AISC 360 Direct Analysis Method would probably be acceptable for use in designing the concrete columns, but it would be necessary to determine and use the Effective Length Factor, k, on the concrete columns in Sway Frames; you couldn’t automatically use K=1 as you can for steel columns, because the concrete code doesn’t permit it.

For notional loads per AISC 360-10, when do you use 0.003 vs 0.002?

The basic value of 0.002 is required as specified in Section C2.2b(1). Section C2.3 give requirements for the reduction of member stiffness, including the application of a t_b factor. This factor is a function of the axial load in the member, which means that the t_b factor can only be calculated after the analysis is complete, but since the t_b factor impacts the analysis results the application of the correct t_b factor requires iterations of analysis, calculating new t_b factors, and reanalyzing. To avoid this the Specification permits that, in lieu of applying the tb factor, an additional notional load of 0.001 times the gravity loads can be applied (for a total of 0.003). Note that t_b is usually 1.0, which means it has no impact on the stiffness reduction. When using the RAM Structural System it is recommended that 0.002 be specified for the Notional Loads and that t_b be set to 1.0. The AISC 360 Direct Analysis Validation report will indicate if t_b should have been less than 1.0 for any members, and the engineer can take the necessary steps by either specifying a smaller t_b, specifying the larger Notional Load, or by increasing the size of those members that require a smaller t_b such that with the larger size t_b can be 1.0. The latter approach is usually the most economical approach.

When using LRFD design what are the load factors to be used for Notional Loads?

The Notional Loads use the same factors as the associated gravity load case. For example, if the load factor on Dead Load is 1.4 the factor on the Dead Load Notional Load is 1.4.

Do I need to include Notional Loads and Seismic Loads in the same combinations?

AISC 360 only requires that Notional Loads be included in the gravity-only combinations unless the ratio of the 2nd order drift to the 1st order drift is greater than 1.7. If that ratio is greater than 1.7 (which is unusual) you are required to include the Notional Loads in all combinations.

Eurocode appears to require that Notional Loads be included in all combinations.

Australia AS 4100 requires that Notional Loads only be included with the gravity-only load combinations, not with wind and seismic combinations.

How does ACI 318-14 address out-of-plumbness?

ACI 318 doesn’t directly address the issue of out-of-plumbness. It doesn’t require that it be modelled or that Notional Loads be applied.

How does Eurocode 1993 address out-of-plumbness and other stability criteria?

This was discussed briefly in the webinar, but in particular see Section 5 Structural Analysis. In particular, Section 5.2.1 Effects of deformed geometry of the structure indicates when an analysis that considers the 2^nd-order effects is required or not (based on the value of a_cr). When required, Section 5.2.2 Structural stability of frames indicates the acceptable methodologies. Section 5.3 Imperfections identifies some of the imperfections that should be considered. Out-of-plumbness (“initial sway imperfection”) is dealt with by using Notional Loads, defined in Section 5.3.2(3) and Section 5.3.2(7). Out-of-straightness (“initial bow imperfection” can be dealt with by applying member notional loads as illustrated in Figure 5.4, but the use of the equations in Chapter 6 provide a more practical way of accounting for this effect.

Is it OK to apply the 10 percent of the gravity loads as the component for notional loads? I see that the range from 0.002 to 0.003 is allowed per AISC so why is 10 percent used?

I am not aware of this requirement in any of the codes. It appears to be rule-of-thumb to ensure that the structure is designed for some minimum lateral force. BS 5950-1:2000 has a similar requirement: Clause 2.4.2.3 Resistance to horizontal forces requires that “the horizontal component of the factored wind should not be taken as less than 1.0% of the factored dead load applied horizontally.” Otherwise, the various requirements for Notional Loads appear to be in the range of 0.2% to 0.5%, not anywhere near 10%.

You recommend using the Effective Length Method for braced frame buildings to take advantage of the fact that K already equals 1. It appears that RAM Frame is only set up for running the Direct Analysis Method. Is this correct? Do you have any suggestions for running the Effective Length Method for a braced frame building?

Typically columns in braced frames are non-sway, and therefore K=1.0 (or potentially less than 1.0, but I am unaware of engineers that use K values less than 1.0 for buildings). RAM Structural System assumes that if AISC 360 is selected as the design code, K=1.0. This is appropriate for both the Direct Analysis Method for all frames and for the Effective Length Method for braced frames, so RAM Frame is capable of doing either method. If you are going to use the Direct Analysis Method you need to select the option to Use Reduced Stiffnesses; if you are going to use the Effective Length Method you should not select that option. The program does not allow you to use the Effective Length Method for moment frames because it doesn’t calculate and apply the K factors (other than 1.0) when AISC 360 is selected as the design code; we have had very few requests for that, since the preferred method for designing moment frames is the Direct Analysis method.

How is analyzing load cases, and then super-positioning, any easier or quicker than analyzing combinations? You still need to combine all the cases into the 100's of combos to get results.

Analyzing a structure, with all of the matrix operations, etc., takes significantly longer than creating a load combination. Limiting the analysis to a few load cases and then combining the results into the 100’s of combinations is significantly faster than combining the applied forces into the 100’s of combinations and then analyzing the structure for all of those combinations. Perhaps more significant, analyzing a few load cases means that there is much less computation results to review, and you are able to see precisely what effect an individual load case had. This tends to get lost if you are only reviewing load combination results; how can you tell, for example, how much of that was caused by the Live Load? Furthermore, the mountain of data produced by analyzing all of those load combinations discourages the engineer from even trying to review the results. It is much more manageable to deal with a few load cases.

Sometimes during analysis I get an error message indicating that an instability was found, and the analysis stops. Which instability is this referring to, and how do I fix it so that it will analyze?

When this error occurs it is usually during the large P-delta analysis. If the sizes initially assigned to the frames are too small, the frames may be truly unstable. To solve this, assign larger sizes. In some cases it is the result of the members being pinned at the joints such that there is no stiffness about an axis, nothing restraining the members to prevent large displacements or rotations. To solve this, provide proper Fixity assignments that properly represent the real structure.

When such an error occurs it is often helpful to turn off the P-delta analysis and perform quick checks of drift and strength. Once these are satisfied the model will usually then successfully analyse without the instability errors.

Is there any implication on the 3D analysis if transfer beams are PT? These beams would be stiffer than reinforced concrete beams and hence the redistribution of forces would be different.

Yes, the higher stiffness of the prestressed transfer beams could (and almost certainly do) have a significant impact on the distribution of forces. The vertical deflection of the frames above caused by the deflection of the transfer girder has a tremendous influence on the stiffness of those frames. The true stiffness of those transfer beams should be modeled as accurately as possible.

RAM Structural System Questions and Answers

Does the RAM Structural System have the ability to optimize steel members?

The RAM Structural System optimizes the Gravity beams and columns (the floor and roof framing), but it does not optimize the Frame beams, columns and braces; the engineer must assign those sizes. The program then provides features to interactively try alternative sizes to quickly determine what the final size assignment should be.

How about concrete members? Can we also optimize?

Member sizes must be assigned, but the program optimizes the reinforcement based on Code requirements and criteria defined by the engineer, including ranges of bar sizes, bar configurations, etc.

Regarding the lateral displacement or drift, is the latest version of the software capable of checking the capacity of the members by just giving a lateral drift limit? If you just input a drift limit say 25mm based on the code tables, can the software optimize the structure?

No, this would require that the program be able to optimize the size of all of the members so that the frames were sufficiently stiff to only drift to the specified limit under the specified lateral loads. The program does, however, provide a report showing the drift at any points specified by the engineer. These values can be compared with the drift limits and then the engineer can resize members as necessary. There is also a specialized module that identifies which members should be resized to most effectively limit the drift. A recording of a very popular webinar previously presented, Building Drift: Understanding and Satisfying Code Requirements, is available for viewing on-demand; there is a discussion of drift and code requirements related to drift, followed by a demonstration of the programs capabilities regarding drift. It can be found at:

Building Drift: Understanding and Satisfying Code Requirements 

How does the RAM Structural System perform stability analysis of non-typical structures (unlike a frame structures)?

The RAM Structural System is special-purpose software specifically for building structures. Hence the features associated with P-delta, Notional Loads, etc., are geared towards buildings. With more effort a non-building structure can be modeled in the program but the program’s method of performing P-delta analysis would not likely be appropriate. STAAD.Pro is more appropriate for that type of structure, and has a full set of features to satisfy the requirements for stability analysis.

How effectively does the RAM Structural System incorporate the various destabilizing parameters discussed in the presentation?

The program offers a robust set of analysis and design options and features, allowing full conformance of code requirements related to stability analysis. The program was written with an emphasis on satisfying the requirements of the building codes through practical analysis and design features that permit the engineer to satisfy those requirements and to produce safe and cost-effective designs while working productively.

When the gravity concrete members are optimized, does it affect the design of the slab system? Or instead transfer the forces in the slab system?

The RAM Structural System doesn’t design the slabs, but the slabs are the mechanism for transferring the loads to the beams. The beams can be specified as T-beams, in which case the program automatically determines the width of the concrete slab acting as the flange of the tee, and the beams are designed accordingly. A different program, RAM Concept, is for the design of floor slabs. In that program the interaction of the beams and slabs is considered in the design of the slab.

Can the software handle other types of slab i.e. slab decking?

Concrete fill on metal deck (for composite beam design), roof decking, and flat slabs with or without drop panels can all be modeled in the RAM Structural System. Decks and slabs can be specified to span either one-way or two-way.

STAAD Questions and Answers

There were several questions specific to STAAD that would require responses longer than could be accommodated here. Information on STAAD is available elsewhere on Bentley Communities. Recordings of past STAAD webinars is available here: http://pages.info.bentley.com/videos/

Information on STAAD training courses is available here: https://www.bentley.com/en/learn/for-users/training-programs

What is the difference between P-Delta and buckling analysis and how can we do buckling analysis using STAAD.Pro?

A P-delta analysis merely determines whether the structure is stable for the loads applied on it. A buckling analysis determines the amount by which the existing load should be magnified, or reduced, to determine the amount of load that the structure can withstand (and still be stable). STAAD has two solvers for doing Buckling analysis – a) The basic (or standard) solver, and, b) the advanced solver. See Section 1.18.2.2.1 of the STAAD Technical reference Manual for more detailed information on the methods used by these solvers.

RAM Elements Questions and Answers

What effects does RAM Elements take into account in its P-Delta analysis?

The second order analysis considers the effect of the lateral displacements (Deltas) at the end of the members in the determination of the member forces (i.e., P-D). The analysis does not consider the second order effects of the curvature of each member (i.e., P-d), the cracking and non-linearity of the material, the creep of the material or the time of application of loads. It uses an incremental-iterative procedure, where loads are incrementally applied to the structural model. Two methods are available for the analysis: The standard or full Newton Raphson method (NR) and the Modified Newton Raphson method (MNR). Note that the program calculates tangent stiffness matrix of the structural model at each iteration and the process is pushed further iteratively until a pre-defined convergence tolerance is satisfied (i.e. the equilibrium point is found). This procedure, in a strict sense, is a non-linear procedure.

Are there plans to incorporate the Direct Analysis Method into RAM Elements?

Although there is no single command that says to perform the Direct Analysis Method, and although the requirements are not automated, everything required for that method can already be accommodated by the program. Member stiffnesses can be modified by the 0.8 and tb factors, P-delta analysis can be performed, Notional Loads can be created and applied, and the appropriate combinations can be created. There are no plans at this time to further automate the process.

RAM Connection Questions and Answers

When will RAM Connection and Limcon be integrated?

It is gradually happening. The only three features left to port over to RAM Connection are the Canadian code, Australian code and tubular connections.

What is the difference between RAM Connection and Limcon?

Both are connection design programs. RAM Connection works standalone and integrated with STAAD.Pro, RAM Structural System, RAM Elements and soon STAAD(X). RAM Connection is available in English, Spanish and Chinese. Limcon DXF/detailing drawings only have simple frontal view. Limcon reports do not have detailed equations. Sections for a specific country must be designed with the same code (e.g. you cannot use US sections with Australian code).

Release Date: April 2020

Version: RAM Concept CONNECT Edition V8 Update 1

Version Number: 08.01.00.26

Download and Installation Instructions

Current and past RAM Concept releases can be downloaded from Bentley Cloud Services at: http://connect.bentley.com

After signing into CONNECTION Center, select Software Downloads under My Services, towards the bottom of the page. Once on the Software Download page, RAM Concept installers can be located by selecting RAM in the Brand menu and clicking Apply or searching for RAM Concept in the Product Search box.

RAM Concept CONNECT Edition V8 Update 1 can also be installed through the CONNECTION Client update service or through the Structural Enterprise Hub.

RAM Concept V8 CONNECT Edition Update 1 can be installed concurrently with versions prior to V8. The installation of this version will automatically uninstall RAM Concept V8.

Product Licensing

More information on product licensing can be found here. A download link to a licensing user guide, which includes instructions for setup and configuring license threshold alerts, can also be found on that web page.

Enhancements

RAM Concept CONNECT Edition V8 Update 1 includes the enhancements discussed below.

Temperature and Shrinkage Strain Loading

Uniform and linearly varying temperature changes and shrinkage/strain changes can now be specified and applied to RAM Concept members.

AS 3600-2018

The AS 3600-2018 design code is now implemented.

Critical Support Ratio Span Segment Property

A new span segment property to define a critical support ratio has been added for all design codes. When span segments are defined with the automatic support width detection option, the defined ratio places the first and last cross section in the design strip at a distance equal to the specified ratio times the distance from the support centerline to the support face. This change applies to all design codes implemented in the program.

As AS 3600-2018 Clause 6.2.3 requires the first and last cross section in the design strip to be placed at 0.7 times the distance from the support centerline to the support face, the default Critical Section Support Ratio is set to 0.7 for all AS 3600 design codes. A default of 1.0 is used for all other design codes, which will place the first and last cross section at the face of the support for rectangular or square columns and walls.

Defect Corrections

RAM Concept CONNECT Edition V8 Update 1 includes the defect corrections discussed below.

File Is Not Recognized Format Error When Importing AutoCAD 18 DWG/DXF

A file format error occurred when attempting to import drawing files saved in AutoCAD 18. The error prevented the file from importing.

Blank Audit Reports

A blank Audit report was generated when the information in the report exceeded 2 MB.

Long Analysis Times – Multi-Threading

In some models, multi-threading caused delays during the analysis, which resulted in longer analysis times.

PT Optimization Run Failure Error Due to Generated Jacks

 A run failure prevented PT optimizations in models with generated jacks and tendons defined with the “Strands” Tendon Specification Type.

Calculation of EC2 Crack Width for Pure Tension Case

For sections with pure tension, the tension zone depth was limited to the section depth for use in the calculation of h_c,ef and s_r,max. The tension zone depth is now permitted to exceed the section depth. This change could result in changes to the reinforcing ratio (typically reducing it) and can increase crack spacing when reinforcement is not satisfied.

CSA A23.3 Shear/Torsion Tension Calculation

When doing the final check for CSA A23.3 shear/torsion tension for the flexural/axial strength, the program was incorrectly including any provided torsion reinforcement in the determination of Vs when calculating the longitudinal reinforcement capacity in accordance with equation 11.21. This could have resulted in an overestimated Vs, an underestimated shear tension force when there was torsion on the section, and an unconservative reported flexural capacity for the section. When performing flexural/axial design in the design passes prior to the final check, the transverse torsion reinforcement was correctly excluded from this calculation, so RAM Concept’s reported designs for this provision considered this effect correctly.

File Compatibility Warning

RAM Concept CONNECT Edition V8 Update 1 can read all previous file formats, but writes files in a format that cannot be read by previous versions.

Security Release Notes

Not applicable to this release.

Release Date: COMING SOON

Version: ISM Revit Plugin CONNECT Edition V11 Update 2

Version Number: 11.02.00.11

Download Instructions

ISM Revit Plugin can be downloaded from Bentley Cloud Services here. After signing in to CONNECTION Center, select Software Downloads under My Services. Once on the Software Fulfillment page, ISM Revit Plugin installers can be located by performing a search on "ISM Revit".

Special Notices

The installation of ISM Revit Plugin CONNECT Edition will automatically uninstall any previous versions that were installed. This version of ISM Revit Plugin can be run in Revit 2019, 2020, and 2021.

ISM Revit Plugin requires ISM and Structural Synchronizer (both of which are installed with Structural Synchronizer). More information on ISM and Structural Synchronizer can be found here.
 

New Features

In this update, we added support for REVIT 2021.

How is Mpl and Mstrip Calculated?

The design procedure for base plate design in RAM Connection is based on AISC Design Guide 1. The Design Guide includes some design examples that will clarify how these parameters are calculated.

The equations used to calculate the plate bending moment in the "Flexural Yielding (Bearing Interface)" check are discussed in Section 3.3.2 of the Design Guide.

The strip moment in the "Flexural Yielding (Tension Interface)" check is calculated assuming the tensile loads in the anchors generate one-way bending in the base plate about assumed bending lines. The location of the bending lines depends on whether the anchors are placed inside or outside the column flanges. See Figure 3.1.1(b) and Figure 4.5.2 in the Design Guide. The program assumes a 45 degree load distribution from the anchor to the bending line to determine the width of the bending strip.

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.

Why doesn't the program report the Anchor anchor pullout in my file?

The Anchor pullout design for US design codes is limited to LRFD methods. When performing ASD design of a base plate report simply indicates: 

NOTES
Anchors only designed for LRFD code

How are biaxial base plates analyzed?

A linear model is used for the contact stresses calculation between a steel base plate and a concrete foundation.  Read the full paper on this topic HERE. This is different from the "both axis" approach which evaluates the plate for major or minor axis moments individually (with axial). 

See Also

Troubleshooting Errors when Assigning Connections

RAM Connection Stalls When Assigning Base Plate Connection

[[The Solution Was Not Found For Load Case Error - Base Plate Design]]

Structural Product TechNotes And FAQs

Problem Description

In the design report for base plates with anchors, near the end of the report is a section called "Max compression and tension" - "Base plate Anchors tension" with a graphic and a legend summarizing the anchor forces. 

The color legend on this graphic is reversed, blue should be at the bottom, and dark red should be at the top.

The values for anchor tension and the columns of the anchor circles is correct only if the legend is flipped.

Solution

The issue is corrected in the current version of Ram Connection.

See Also

Structural Product TechNotes And FAQs

Under Construction

Under Construction

My model takes a long time to analyze. What can I do ?

Size of the model and number of load cases directly affect the analysis time. So leaving out any detail that is not important for the analysis is something worth considering. For example there may be stairs, handrails, access ladders, monorails, connection components like gusset plates, stiffeners and such other entities that may be left out from an analysis model. Also there may be certain loads/combinations that you may already know will not be governing the analysis/design. Avoid including these in your model, specially if analysis time is a concern. Using a relatively coarser mesh, changing some of the primary loads to reference loads, changing REPEAT LOADs (if any) to LOAD COMBINATIONs (if the analysis is linear one), are some of the other things to try out. Also make sure that you are using the latest STAAD.Pro CONNECT Edition (ver 22.05.00.131 and up ) as that has the faster solver available for all license types (Advanced and Basic). Also last but not the least, if you are trying to run the analysis for a file which is on a network drive, try copying the file to your local machine and see if the analysis time improves. Software performance can be affected significantly by network speed/activities.

This contains STAAD.Pro wikis related to "Analysis" topics.

1. Direct Analysis related questions
2. Pushover Analysis related questions
3. Miscellaneous Analysis Solutions
4. Pushover Analysis Solutions
5. Seismic Analysis Solutions
6. STAAD Advanced Analysis
7.  STAAD.Pro Buckling Analysis
8. STAAD.Pro Dynamic Analysis
9. STAAD.Pro Eigen Solution FAQ's
10. STAAD.Pro Instability and Zero Stiffness FAQ's
11. STAAD.Pro PDELTA Analysis FAQ's
12. STAAD.Pro Response Spectrum FAQ's
13. STAAD.Pro Steady State Module
14. STAAD.Pro Time History Analysis FAQ's
15. [[Long Analysis Times]]

RAM Structural System CONNECT Edition Version 17.02 SES Release Notes

Anticipated Release Date: January 2021

This document contains important information regarding changes to the RAM Structural System. It is important that all users are aware of these changes. Please distribute these Release Notes and make them available to all users of the RAM Structural System.

Installation Instructions:

If you have enabled the CONNECTION Client you will automatically be notified of the newest version and will be able to update through that service by simply selecting the update command. Otherwise, this version can be found on the Bentley Software Fulfilment web page by logging into CONNECT Center and selecting the Software Downloads icon. Search for “RAM Structural System” and select the latest version.

Important Notices:

This version automatically converts databases created in previous versions to the new database format. Note that a backup file is created automatically when a database is converted; the name of the database is the same, with “Orig” and the version number appended to the name. The file has an extension of “.zip” and is located in the same directory as the original database.

The previous steel tables and load combination templates supplied with the program will be replaced with new tables and templates of the same name. If you have customized any Master or Design tables or load combination templates supplied with the program without changing the file names, those file names should be renamed from the original RAM table names prior to installation to prevent your changes from being lost.

Tutorial:

Except for minor corrections, the Tutorial Manual has not been updated but is still valid. The appearance of some parts of the program in this version may differ from that shown in the Tutorial.

Bentley CONNECT and Product Licensing FAQ:

Appendix A at the end of these Notes contains important information on the features and capabilities provided to you through Bentley CONNECT, and for important information on configuring Bentley CONNECT Licensing. These were first implemented in RAM Structural System v16.00. If you have not already done so, you are urged to configure your licensing thresholds so that warnings are given if you are attempting to launch the program that would result in an overuse.

Appendix B at the end of these Notes contains a description of features available in the RAM Structural System to help prevent inadvertent use of unlicensed modules. Refer to that document for more information. Note that with CONNECT Licensing, warning messages are given in the event there is no license available, so it generally isn’t necessary now to block modules using that feature. Note: At some point in the future this feature will be removed since it is redundant. To provide protection against inadvertent overuse of licenses, license threshold limits should be set as explained in Appendix A.

Beginning with RAM Structural System V17.00 the licensing was changed; the licenses on the individual modules (e.g., RAM Steel, RAM Concrete, RAM Frame, RAM Foundation) were consolidated into a single package, RAM Structural System. See Appendix C at the end of these Notes for more information on this license consolidation.

Security Risk Advisory:

Not applicable to this release. Every effort is made to ensure that there are no security risks in the software. There are no known security issues, no issues were addressed in this version.

New Features and Enhancements:

For details on these new features and enhancements, refer to the manual .pdf files available from the Help menu in each module or from the Manuals folder on your hard drive.

Simpson Strong-Tie Yield-Link Moment Frame Connection

The requirements for the analysis and design of the Yield-Link moment frame connection have been comprehensively implemented, with close coordination with the engineers at Simpson Strong-Tie. The connection is assigned using the Assign – Beams – Frame Beam Connection Types command. The influence of the connection on the joint and frame stiffness is automatically determined and applied in the analysis. The requirements of AISC 360-10 and AISC 360-16 have been implemented for the basic steel design checks, and the requirements of AISC 341-10 and AISC 341-16 have been implemented for the seismic design checks of the connection, columns, and beams. Pertinent panel zone shear check and strong column – weak beam requirements from AISC 358 are also implemented.

Crash Reporting

In order to improve the stability and reliability of the program we have implemented a feature in which a report is delivered to Bentley anytime the RAM Structural System program crashes. When a crash occurs, a dialog is given requesting a description of the events leading to the error. Please provide us with as much pertinent information as you can (what series of events that you did prior to the crash, etc.), and then select the command to Send Error Report. This will assist us in locating the cause of program crashes, and better enable us to eliminate their causes.

Verification of File Integrity on Save

When Save is invoked, a check is now made on the integrity of the saved file. If it appears that key portions of the database have failed to save (due to, for example, a system disruption during the Save), a second attempt will be made to save the file; if there appears to still be an error, an attempt will be made to create a backup of the original database (in the state it was at the last Save, it won’t contain any of the recent changes made since the last Save), and a Warning message is given notifying the user that there was problem with the Save. It is possible that the database files that would still be in the Working directory are correct, and the user is advised to copy those to another directory before closing the Warning message and the program. The user can then attempt to open the model by navigating to the directory to which the database files were copied. Note that this is intended to prevent an exceptionally rare problem of unknown cause, but one which resulted in corruption and loss of the model. It is believed that this new workflow will prevent the loss of the model. Please report to Technical Support when this message is given so that we can attempt to determine the cause.

IBC Storage Live Load Reduction on Beams

IBC 2018 Section 1607.11.1.2 and Section 1607.11.2.1 allow Storage live loads to be reduced up to 20% if the member supports load from two or more levels. This was previously implemented for columns, but not for beams, such as transfer girders, that support load from two or more levels. Storage Live Load reduction per the IBC has now been implemented for beams that support load from two or more levels, allowing of a reduction of up to 20%.

IBC Alternate Live Load Reduction Method

The IBC includes both a basic Live Load Reduction method (Section 1607.11.1) and an alternate Live Load Reduction method (Section 1607.11.2). Beginning with IBC 2015 a subtle but important change was made to the Alternate method: previous to IBC 2015 the requirement stated that the reduction for horizontal members (i.e., beams) is limited to 40% and the reduction for vertical members (i.e., columns) is limited to 60%. Note that this meant that a column carrying load from only one level could be reduced up to 60%, and a transfer girder carrying load from more than one level could only be reduced up to 40%. Beginning with IBC 2015 the requirements now say that for members receiving load from one level only the reduction is limited to 40% and for members receiving load from two or more levels the reduction is limited to 60%. In prior versions of the program the requirements of the pre-IBC 2015 were implemented but beginning with this version the requirements given in IBC 2015 and later are now used.

Detailing Values in Master Steel Tables

Previously the Master Steel Tables only contained the design section dimensions and properties, not the detailing section dimensions because those detailing values were not used by the program. The new Yield-Link feature now uses some of these values, so the Master Table format has been enhanced to include these values:

       Depth_det  Tw_det  Bftop_det  Bfbot_det  Tftop_det  Tfbot_det  ktop_det  kbot_det  k1top_det  k1bot_det  T_det

These detailing values have been added to the RAMAISC Master tables provided with the program. At this time they have not been added to any of the other Master tables provided by the program, but the user can edit those tables to include those values if desired. See Section 8.4 of the RAM Manager Manual for a complete description of the new data format.

Note that existing models will not automatically use these revised tables. In order to update the tables used by a model, invoke the Criteria – Master Steel Table command in the RAM Manager, and follow the instructions given there.

If it is desired to use user-created Master tables with the Yield-Link feature it will be necessary to add the detailing values to those tables.

Updated Table of Decks – US

The ramdecks.dck file, the file that contains the composite decks used in the United States, has been updated based on the latest deck data made available by the deck manufacturers. The Wheeling decks were removed since that deck is no longer produced, and New Millennium decks were added. The values for Ybar (which only impacts the design of beams using the old ASD 9th Edition code) were slightly modified for ASC 3W and Vulcraft 1.5VL. The depth was changed from 2" to 2.0625" for Verco W2 Formlok, which also changed AcRib and Ybar (which will slightly impact designs, including loads from deck self-weight).

New models will use the updated values, existing models will continue to use the previous values. If it is desired to update the tables used by an existing model, invoke the Criteria – Design Steel Tables command in the RAM Manager, and follow the prompts given there.

Updated LH Joist Tables and 2.5K Joists

In the Steel Joist Institute’s recently released 45^th Edition K-Series, LH-Series, DLH-Series, Joist Girders Standard Specifications Load Tables and Weight Tables for Steel Joists and Joist Girders Catalog, the load tables for the LH-series joists have been updated. The joist series has been expanded to include several new LH joist sizes, and the range of spans listed for each joist has been increased. In many cases the allowable loads have been increased. The RAMSJILH.JST and RAMSJI.JST tables have been updated to include these changes.

The SJI Catalog also includes 2.5K joist substitutes, a series of 2.5” deep members intended for spans of 10 ft. or less. These joist substitute members have been added to the RAMSJIK.JST and RAMSJI.JST tables.

Steel Joist Camber

In the Steel Joist Institute 45^th Edition K-Series, LH-Series, DLH-Series, Joist Girders Standard Specifications Load Tables and Weight Tables for Steel Joists and Joist Girders Catalog, the standard joist camber is given in Table 4.6-1. When joists are fabricated, they are fabricated with the camber given in that table unless otherwise specified by the engineer. Typically, joists are designed for strength based on the Total Load, and for deflection based on the Live Load (typically L/360). It is not an SJI requirement to assign deflection limits on Dead Load or on Total Load, and the joist tables in the joist manual are based only on a deflection limit of L/360 on the Live Load. Because it would be fairly rare to specify a deflection limit on Total Load, the program for simplicity did not consider camber when checking a deflection limit on Total Load. This has now been enhanced. The Standard Joist Selection report now lists the standard SJI camber, and lists both the Total Load deflection and the Net Total Load deflection (which is the Total Load Deflection minus the camber). In the selection of the joist, if there is a Total Load deflection limit set by the user, the program compares that limit with the Net Total Load deflection. The Deflection Summary report also now lists the Net Total Load deflection and the camber.

Ground Level for Wind

In RAM Frame the Ground Level is assumed by default to be at a level below the lowest Story. However, the user has the ability to specify any level as the Ground Level, for example when a structure has a basement. Not only does this impact the lateral constraints for the analysis of levels at and below the Ground Level, it also impacts the generation of the wind loads. The program now allows the Ground Level for wind loads to be specified independently of the Ground Level for analysis.

Eurocode Seismic Forces

In RAM Frame seismic loads per Eurocode EN 1998-1:2004 + A1:2013 can now be generated. It is based on Section 4.3.3.2 Lateral Force Method of Analysis. The Eurocode dynamic response spectra analysis can also be performed. Both methods have the option to include the accidental torsional effects defined in Section 4.3.2.

Diaphragm Section Cuts Enhancement

The Diaphragm Forces report has been enhanced. Previously the report had a section that listed the combined Diaphragm and Frame Member Forces. That section of the report is still included, but when a section cut crosses one or more beams there is a new section of the report that lists the Diaphragm Only Forces. This makes it easier to identify the forces in the diaphragm itself.

The report has been expanded to also now show the force values at discrete points along the section cut.

Vertical Modal Response

When the option to Include nodal mass in Z-direction in the Criteria – General command is selected in RAM Frame, and the diaphragms have been specified as Semirigid, the Periods and Modes report has been modified: Z-direction (vertical) values have been added to Modal Participation Factors, Modal Direction Factors, and Modal Effective Mass Factors.

DuraFuse Option for Rigid Panel

For the DuraFuse moment frame connection there is now an option to specify the Panel Zone Stiffness to be considered rigid in the analysis (rather than using the Calculated Spring Stiffness). Contact DuraFuse Frames, LLC, for information on when it is appropriate to assume that the panel is rigid.

Stress Display in Concrete Wall

In the option to display stress contours (the Mesh Options button in the View/Update command in the Concrete Wall module), options to show the contours for SVMax, SavgMax, and S Von Misses have been added. Options have also been added to show the stresses on the Primary Face versus the Secondary Face.

Data Extractor

The Data Extractor is invoked using the Post-Processing – Extract Data command; it provides a powerful means of extracting model, design, and analysis results data. Several improvements have been made, both in this version and in version V17.01 but were not documented. It has been enhanced to extract additional data. For more information, see Appendix D RAM Data Extractor in the RAM Manager Manual.

The following new fields have been added to existing tables in the Geometry category:

• ColumnData table:
  • Size
  • Depth
  • Width
  • StoryHeight
  • Grid_Label
  • Several values associated with the DuraFuse connection

• BeamData table:
  • LeftOfBeam (condition at left: Beam, Edge, or Opening)
  • RightOfBeam
  • DistanceToLeft (distance to adjacent beam, edge, or opening; -1.0 indicates that there is no deck on the beam)
  • DistanceToRight
  • Size
  • CantLeftLength
  • MidSpanLength
  • CantRightLength
  • Some values associated with the DuraFuse connection

• BraceData table:
  • Length

The following new fields have been added to an existing table in the Criteria category:

• RAMManagerCriteria table:
  • Model_Name
  • Export_Time_Stamp (the time at which the data was extracted)

Several new tables have been added to the Geometry category:

• DeckData
• DeckProp_Comp
• DeckProp_NonComp
• DeckProp_Conc
• JointData

A new table has been added to the Criteria category:

• SteelBeamJoistCriteria

Several new tables have been added to the Loads category.:

• LoadCombosData
• GravLoadReactionsOnBeams
• GravLoadReactionsOnColumns
• GravLoadReactionsOnWalls
• LnLoadTakeDownOnWalls
• PtLoadTakeDownOnWalls

ISM – Typical Layout Types

Previously if a model used a layout type on more than one story it was necessary to modify the model such that each story had its own layout type before the model could be exported to ISM. That is no longer necessary; a model in which a layout type is used on two or more stories can be exported to ISM, and the relationship of the stories and layout types will be preserved.

Technology Preview Features:

Technology Preview features are features that are still under development, and have not been completely certified. They are made available because they may offer significant benefits to the user, even in their current state. If you use these features, please provide feedback so that we can refine the features.

iTwin Design Review

Bentley iTwin Design Review is a collaborative service hosted on the web that allows two or more interested parties to communicate with one another in the context of a 3D model or, more accurately, an iTwin.

The iTwin Services Add-in within the desktop application publishes the analysis model to an iTwin Design Review session, allowing collaboration that facilitates review of design work in progress. The web-based interface (accessible with a web browser) of Design Review offers a set of commands for navigating, viewing from different perspectives, isolating key elements, and clipping views. Several review tools are included with the service:

• Measurements, including distance, area, location, radius, and angle
• Querying elements for physical information, such as dimensions, construction materials, and coordinates
• Querying analytical information, such as member fixities, applied loads, and reactions

Many aspects of iTwin Design Review are particularly relevant to engineering analysis workflows. Project managers or other stakeholders in a project may not be skilled in, or have access to, the analytical software used by engineers to analyze and design a structure or facility. These individuals may instead have a practice of reviewing a set of 2D drawings or a BIM model that is disconnected from the engineering analysis models. In this case, the reviewer may not have a complete understanding of the assumptions used by the designers. iTwin Design Review can therefore help project managers catch incorrect assumptions or errors during the design phase and before it becomes a construction problem. Some of the practical applications of this technology to the traditional engineering review and collaboration process include:

• Have a conversation with participants via chat in the context of a 3D model, annotating and marking up objects, and posting questions, comments, and markups for specific stakeholders.
• Include stakeholders, such as project managers and other engineering disciplines, that are not users of Engineering Simulation software, in this review process. All that is needed is a web browser, anyone invited can contribute to the review.
• Resolve issues raised by team members directly in the desktop application.
• Save a record of conversations (chats) in the review so that reasons for key decisions can be revisited at a later point if needed.
• Create specific views of the structure, with objects of interest isolated and zoomed to, that collaborators and reviewers can see immediately without needing to recreate the view themselves.

iTwin Design Review can be invoked by selecting the iTwin Design Review icon on the Manager screen.

This feature is still being developed/refined. For more information and the most current instructions on the use of this feature, see:

iTwin Services for Engineering Analysis - RAM | STAAD | OpenTower Wiki - RAM | STAAD | OpenTower - Bentley Communities

DataCheck

In the Modeler, the Integrity – DataCheck command has been enhanced to include additional checks:

• Members slightly offset from grids. If a member is very nearly but not exactly attached to a nearby grid intersection, it is often an indication that the member is not attached to the intended snap point, but rather to a nearby point. This is generally not a problem, such conditions are allowed, but when the other framing around this member use the correct grid point, in very rare cases this condition can cause gravity loads to be incorrectly distributed or cause the analysis to terminate.
• Members very nearly horizontal or vertical. If a beam or wall is very nearly but not exactly horizontal in plan, it is often an indication that the member end is not attached to the intended snap point, but rather to a nearby point. Same for a member that is very nearly but not exactly vertical in plan. This is generally not a problem, such conditions are allowed, and in some cases intended, but when the other framing around this member use the correct snap point, in very rare cases this condition can cause gravity loads to be incorrectly distributed or cause the analysis to terminate.
• Deck or Load polygon edges misaligned with member. If the edge of a Deck or Surface Load polygon very nearly but not exactly coincides with a beam or wall, it is often an indication that the polygon vertex was not attached to the intended snap point, but rather to a nearby snap point. Alternatively, it may be an indication that the beam or wall was not modeled exactly as intended. Deck polygon edges should coincide precisely with beams and walls; surface load polygons are not required to coincide with beams and walls, but this condition, in which the edge very slightly diverges from the beam or wall, should be avoided. The program generally deals with this problem correctly, but in rare cases this condition can cause composite properties to be incorrectly assigned to a beam, cause gravity loads to be incorrectly distributed, or cause the analysis to terminate.

If any of these warnings are given it is recommended that the model be modified to eliminate the condition, or that the engineer carefully inspect the resulting designs to verify that properties and loads were properly and correctly assigned and distributed, not only to the member referenced, but to surrounding members as well.

These conditions are rare when the model has been created in the Modeler, but are more prevalent when the model has been imported from Revit, which does a poor job of enforcing modeling precision unless great care and effort is taken there by the person creating that model.

Note that that because these new checks are still Technology Preview features, these new checks are not included in the checks performed by the Datacheck by default. See Appendix D at the end of this document for instructions on setting up the program to include these checks when the Datacheck is invoked.

Error Corrections:

Some program errors have been corrected for this version. Corrections made to graphics, reports, Modeler functions, program crashes, etc., that were considered minor are not listed here. The noteworthy error corrections are listed here in order to notify you that they have been corrected or to assist you in determining the impact of those errors on previous designs. These errors were generally obscure and uncommon, affecting only a very small percentage of models, or had no impact on the results. The errors, when they occurred, were generally quite obvious. However, if there is any question, it may be advisable to reanalyze previous models to determine the impact, if any. In each case the error only occurred for the precise conditions indicated. Those errors that may have resulted in un-conservative designs are shown with an asterisk. We know these errors are disruptive, we apologize for any inconvenience this may cause.

Manager

SNOW VS ROOF LIVE LOAD*: In the Criteria – Member Loads command, if the selection for Snow vs Roof Live Load was Consider Roof Live Loads, Ignore Snow Loads, and the Code for Live Load Reduction selection was changed to NBC of Canada, BS 6399, Eurocode, Eurocode UK NA, AS/NZS, China, or Hong Kong, the selection for Snow vs Roof Live Load changed to Consider Snow Loads, Ignore Roof Live Loads.

Effect: If the Code for Live Load Reduction selection was changed to any of the codes listed, the selection for Snow vs Roof Live Load may have unintentionally switched to Consider Snow, Ignore Roof Live Load, resulting in Roof Live Loads being ignored in analysis and design.

Modeler

FRAME COLUMNS ON GRAVITY WALLS: If the end of a Gravity wall shared the same point as a Frame column, and a Frame column above was supported by that Frame column, a DataCheck warning was erroneously being displayed indicating that a Frame column was supported by a gravity member (referring to the Gravity wall). The warning should not have been displayed since there was also a Frame column at that location.

Effect: Erroneous DataCheck warning for an acceptable configuration.

Steel Beam

WEB OPENING TEE BUCKLING CAPACITY CHECK: In the design of beams with web openings per AISC Design Guide #2, it is not required to perform the buckling capacity check of tees with an aspect ratio less than 4.0. However, the program incorrectly and unnecessarily calculated the demand/capacity ratio for that check and potentially listed that value as the controlling demand/capacity ratio for the opening, but correctly did not flag the opening as failing if that ratio exceeded 1.0. Hence it was possible that the program listed a demand/capacity ratio greater than 1.0 but did not indicate that the opening failed.

Effect: Potentially, in View/Update and on-screen, an incorrect demand/capacity ratio greater than 1.0 was listed for the opening, even if the opening passed all of the necessary design checks (the design report listed the correct value).

CASTELLATED BEAMS FREEZING: While optimizing castellated beam sizes for a range of opening spacing, e, the program may have failed to correctly determine an e-max for some beams’ designs.

Effect: The optimization process for certain castellated beam designs stalled during a Design All, the design of the remaining beams could not be obtained.

NON-COMPOSITE BEAM SPAN/DEFLECTION DISPLAY VALUES:  When the Show Values option of the Process – Design Colors command was invoked, non-composite beams did not show the correct deflection interaction value if the deflection criteria for the beam only included a limit on the Live Load L/d ratio.

Effect: The designs were correct; the beam designs correctly considered the Live Load L/d deflection limit for non-composite beams. However, the Process – Design Colors command did not show the correct deflection interaction value in the display if the deflection criteria for the beam only included a limit on the Live Load L/d ratio.

Steel Column

AISC 360-16 DESIGN WARNING: In the calculation of the P-delta multiplier, B1y, if alphaPr was greater than Pe1y the warning given by the program incorrectly stated that alphaPr was greater than Pe1x.

Effect: Warning text error only. The warning incorrectly referenced Pe1x rather than Pe1y.

Concrete Beam

ACI 318 SEISMIC PROVISION DESIGN SHEAR, Ve*: When only some of the load cases were analyzed in RAM Frame, the portion of Ve attributed to the gravity load cases was sometimes greater than the actual gravity load case shear.

Effect: Design shear, Ve, used in ACI 318-11 Section 21.5.4.1 and ACI 318-14 Section 18.6.5.1, may have been wrong; when the error occurred, it was almost always conservative, but not necessarily, so in rare cases may have resulted in an unconservative design. If all of the load cases in RAM Frame were analyzed, the error did not occur.

CONCRETE BEAM FORCE ENVELOPES*: If  not all cases were analyzed in RAM Frame, the Force Envelopes in Concrete Beam were calculated incorrectly.

Effect: Incorrect results.

Concrete Column

COLUMNS UNBRACED OVER MULTIPLE STORIES*: When calculating the special provision shear requirement of ACI 318-14 Section 18.7.6.1.1 (or analogous clauses in earlier codes), if a column was unbraced over multiple stories, the program did not take into consideration the probable moment contribution from beams in the upper story segments of the column when designing the lower story segments of the column.

Effect: Potentially there was an underestimation of special provision shear.

ACI 318-11 SECTION 10.3.5 LIMIT ON NET TENSILE STRAIN: The limit of 0.004 on the net tensile strain of the reinforcement for lightly loaded columns was not being applied.

Effect: The maximum reinforcement ratio for columns imposed by the minimum limit on the tensile strain at nominal strength was not being considered.

Concrete Wall

COUPLING BEAMS COMPOSED OF DIFFERENT WALL PANELS*: If a coupling beam was composed of portions of two wall panels (i.e., the upper portion of the coupling beam was from the panel above and the lower portion of the coupling beam was from the panel below), the design forces may have been incorrect, only including the forces in the lower portion of the coupling beam.

Effect: Incorrect design of coupling beams for the condition described.

COUPLING BEAM UPDATE DATABASE: If changes were made to the reinforcing for coupling beams, and then saved using the Update Database command, the original design results were not cleared, and a subsequent View/Update would show the results from the original configuration rather than the saved configuration.

Effect: Incorrect design results were shown in View/Update after the coupling beam reinforcement was changed and updated.

Frame – Analysis

USER-DEFINED WIND LOADS ON SEMIRIGID DIAPHRAGM*: When the wind loads were user-defined rather than generated and the diaphragm was specified as Semirigid, the wind load distribution on skewed diaphragm geometries were not correct because the program used real building lengths instead of projected lengths. Even though the total applied load was correct, the wind load profile (wind load distribution along building surfaces) was not correct.

Effect: For diaphragm geometries with skewed faces, total wind load was correct, but the wind load distribution along any given face was not.

USER-DEFINED WIND LOADS ON SEMIRIGID DIAPHRAGM*: If deck assignment (deck polygon) did not fully extend out to the end of slab edges and the deck was specified as Semirigid, the program applied user-defined wind loads at wrong locations. It was expected such wind point loads should be applied to mesh nodes close to edges, but they were applied to nodes at other locations.

Effect: Wind loads were not assigned to nodes along edges if the deck polygon did not extend out to that slab edge. The error was generally very obvious if the Process – Results – Applied Story Forces command was invoked to display the loads on the diaphragms.

USER-DEFINED WIND LOADS ON SEMIRIGID DIAPHRAGM: When the wind loads were user-defined rather than generated and the diaphragm was specified as Semirigid, the applied loads were greater than necessary if the diaphragm had a concave geometry.

Effect: The applied wind loads were greater than what the user had defined.

INCORRECT MEMBER FORCES FOR BEAM WITH SPRING CONNECTION AND SEMIRIGID DECK*: The program produced incorrect member forces for beams if the beam had been assigned a spring connection and the deck was Semirigid.

Effect: Member forces for beam were incorrect.

INCORRECT FORCE/MOMENT DIAGRAGMS FOR BEAM WITH SPRING CONNECTION: Member Force diagrams were incorrect on beams if the beam had been assigned a Spring connection type and the option to Include Effects for rigid end zones was selected.

Effect: The diagram was shifted and the program was not consistent in properly displaying the values at rigid-end-zone distances versus at the face of joint.

CRASH WHILE ATTEMPTING TO DISPLAY GRAVITY WALL STRESS: Gravity walls are included in the analysis if they support two-way decks and the option to include them in analysis is selected. However, if gravity walls were included in a previous analysis and then not in the current analysis, the program subsequently crashed if the Process – Results – Stress and Internal Force Contours command was invoked.

Effect: Program crash.

USER-DEFINED STORY WIND AND SEISMIC LOADS*: In a very rare case, user entered values for user-defined story forces were lost either upon closing the load case dialog or after an analysis was performed.

Effect: User entered values for wind and seismic forces were lost.

NBC OF CANADA 95 WIND LOAD CASE REPORT: For the NBC of Canada 1995 wind load case, the Loads and Applied Forces report only listed the building frequency for the X-direction even if both X- and Y-direction wind cases were analyzed.

Effect: Report error only, the Y-direction frequency was not listed.

EUROCODE 1991-1-4:2005 AND EUROCODE 1991-1-4:2005 UK NA WIND CASE: The program crashed for Eurocode 1991-1-4:2005 and Eurocode 1991-1-4:2005 UK NA wind load cases if the ground level was not At Base in the Criteria – Ground Level command.

Effect: Program crash.

EUROCODE ENV 1991-2-4:1995 WIND LOAD CASE*: For Eurocode ENV 1991-2-4:1995 wind load case, the program did not immediately recognize changes to the Ground Level selection in the Criteria – Ground Level command, the program continued to use the ground level from the previous run.

Effect: Calculated wind forces were not correctly reflecting ground level set for that run.

ZERO WIND PRESSURE FOR CHINA GB50011 WIND LOAD CASE*: The China GB50011 wind load generator was not generating any wind loads.

Effect: No wind pressure and forces calculated for the load case.

DISPLAYING MEMBER FORCES ENVELOPE VALUES: The Process – Results – Member Forces Envelope command took an exceptionally long to display member force envelope values on screen if the model included dynamic load cases.

Effect: Prohibited viewing of member forces envelopes if there were dynamic load cases.

CRASH WHEN SWITCHING BETWEEN MODES: The program would sometimes crash when switching between the various modes (Load Combinations, Steel, Drift, and Shear Wall Forces).

Effect: Program crash.

DURAFUSE PANEL ZONE ROTATION FOR DYNAMIC LOAD CASE: For dynamic load cases, the Member Forces report for a column in a moment frame using the DuraFuse moment frame connection reported incorrect Panel Zone Rotation values.

Effect: Incorrect Rotation values reported.

STRESS CONTOUR VALUES NOT DISPLAYED IN PLAN VIEW: When displaying stress contours in Plan View, the option to Show Stress Contour Values did not work, the values were not displayed.

Effect: Stress contour values could only be displayed in 3D View, not in Plan View.

STRESS CONTOUR DISPLAY IGNORED EXTENTS: If the extents of the view had been limited using the View – Extents command, those extents were ignored when the stress contours were displayed.

Effect: Wall and diaphragm stress contours were displayed for all levels, even if the user had attempted to limit the stories being displayed using the View – Extents command

PROGRAM FREEZE WHEN DISPLAYING STRESS CONTOURS FOR LOAD COMBINATIONS: In Load Combinations mode, the program become unresponsive when the Process – Results – Stress and Internal Force Contour command was invoked.

Effect: The contours could not be viewed in Load Combination mode.

ECCENTRIC GRAVITY MOMENT AT TILT-UP WALL GAP JOINTS: Eccentric gravity moment from gravity beams framing into the joint was intended to be equally distributed to the tilt-up wall panels common to the joint. If both (or all, if more than two panels converged at a joint) panels had been assigned to have a gap there, the moment was equally distributed properly, but if one of the panels had not been assigned to have a gap there, it was not assigned any eccentric gravity moment; it was all assigned to the panel with the gap assignment.

Effect: Tilt-up panels without gap assignments may not have been designed for the intended eccentric gravity moments from beams framing into the wall end.

CRASH AFTER DELETING LOAD CASES: If load cases were deleted after they had been analyzed the program was susceptible to crashing on the subsequent analysis.

Effect: Program crash.

CRASH WHEN SWITCHING BETWEEN MODES: Program crashes were common after invoking the Shear Wall Forces mode and then switching to another mode.

Effect: Program crash.

Frame – Steel Standard Provisions

VIEW/UPDATE WITH DYNAMIC LOAD CASES: Investigation of different beam sizes in the View Update dialog for models with dynamic load cases was often unresponsive, leading users to believe a crash had occurred.

Effect: While investigating other beam sizes in View Update dialog box, the program became unresponsive while internally processing combinations with dynamic load cases. Models without dynamic combinations did not result in delays when investigating alternate beam sizes.

SIDEPLATE OR DURAFUSE CONNECTION UNBRACED LENGTH: For the SidePlate and DuraFuse connections, the unbraced length of beams and columns should be the clear distance between faces of members (regardless of the selections for Rigid End Zones in the Criteria – General Criteria command). However, the program was calculating the unbraced lengths based on those selections.

Effect: For SidePlate and DuraFuse connections, the unbraced length of members used in design was correct if the option to Include Effects was selected with 0% reduction, but any other selection would result in a conservative (longer) unbraced length. The analysis was correct, only the unbraced length may have been incorrect.

SCBF COLUMNS - MAX COMPRESSIVE FORCE: The 0.75 reduction factor was not applied to the transient load combinations for SCBF Columns designed according to AISC 341-10 and -16 ASD.

Effect: The max compression design force for SCBF Columns designed according to AISC 341-10 and -16 ASD and governed by combinations with transient loads was not reduced by the transient load reduction factor of 0.75. Designs may have reported incorrect controlling load combinations.

Frame – Steel Seismic Provisions

AISC 341-16 BASIC REQUIREMENTS FOR SCBF BEAMS*: AISC 341-16 Section F2.5a Basic Requirements requires that SCBF members satisfy the requirements of Section D1.1 for highly ductile members; however, the program was only applying the moderately ductile limits on SCBF beams.

Effect: SCBF beams checked according to AISC 341-16 Basic Requirements, Section D1.1, used Moderately Ductile rather than Highly Ductile limits. Some beams should have failed under the more stringent flange b/tf limit for highly ductile members.

CONTINUITY PLATE CHECK STATUS: When a Joint Code Check for IMF and SMF joints was performed and it was determined that continuity/stiffener plates were required but web plates were not, the symbol displayed for the joint was incorrect, indicating that web plates were required. Also, the Seismic Provisions Joint Code Check report incorrectly stated that both web plates and stiffeners were required although it correctly only listed the stiffener plate information.

Effect: When stiffeners were required, both the symbol displayed for the joint and the report incorrectly indicated that web plates were required.

ROUND HSS REQUIRED COLUMN STRENGTH: The reported required column strength per the requirements of Section D1.4a of AISC 341-10 and AISC 341-16 for SCBF and BRBF with round HSS columns with different orientations for columns within a multi-story stack was calculated incorrectly; the amplified seismic load Emh or Ecl in certain chevron bracing configurations was incorrect.

Effect: The amplified seismic load, Emh or Ecl, determined respectively according to Sections D1.4a of AISC 341-10 and AISC 341-16 for SCBF-V and BRBF-V for round HSS columns was incorrect when columns within a multi-story column stack had varying column orientations. When no braces frame into the top of column in a given axis, the column is designed for an accumulation of axial loads from supported stories and any unbalanced beam shear reactions. When braces frame into the top of the column in a given axis, only the vertical reaction of the braces and any accumulated axial loads from supported stories are considered. When the column orientation for a round column changed from level to level, these values were incorrectly mixed.

DURAFUSE HSS JOINT CHECK*: Some DuraFuse joint configurations at HSS columns were incorrectly considered invalid and so were not designed.

Effect: The joint check for the DuraFuse connection was not performed in many cases when the column was an HSS.

Data Extractor

INCORRECT DATA EXPORTED FOR GRAVITY BEAM REACTIONS: In the GravLoadReactionsOnBeams tab of the Loads tables, there were several columns that should have been expanded to show an array of values rather than a single value. For example, Columns BC-BH listed the tributary areas on the beam; however there are three such values for each beam corresponding to the left cantilever, the span, and the right cantilever. But only a single value was listed, and it was incorrect, it didn’t even correspond to the value for any of those segments. There were several other columns with similar problems, notably Columns CA-CB listing the MultiLevelFlag. These columns have now been expanded to contain the full arrays of values.

Effect: Columns BC-BH, BQ-BT, CC-CN, CA-CB and CU-CZ had erroneous values. The correction required that several existing columns of data were relocated to the right. Of note, Column DS, that contained the StoryID, is now Column EQ.

NOTE: The format of the table on the BravLoadReactionsOnBeams tab has been modified! If you have written any spreadsheets or programs that use any of the columns to the right of Column BB you will need to correct your program to use the relocated columns. Review the documentation carefully to see the new format.

INCORRECT DATA EXPORTED FOR GRAVITY COLUMN REACTIONS: In the GravLoadReactionsOnColumn tab of the Loads tables, there were several columns that should have been expanded to show an array of values rather than a single value. For example, Columns Q-AB listed beam reactions on the sides of the columns, used for skip loading and unbalance moments; however only a single side’s value was listed rather than all four sides’ values, and that value that was listed was wrong. All of the columns to the left of AU had a similar problem. These columns have now been relocated and expanded to contain the full arrays of values.

Effect: Columns Q-AB and AV-CQ had erroneous values. Columns Q-AB have been abandoned (filled with 0.0 and labeled as unused), and the values in Columns Q-AB and AV-CQ have been expanded and relocated to the right of Column AU.

NOTE: Values in Columns A-P and AC-AU remain unchanged, but all other Columns have been reformatted. If you have written any spreadsheets or programs that use any of the affected columns you will need to correct your program to use the relocated columns. Review the documentation carefully to see the new format.

Appendix A

Bentley CONNECT Licensing – Subscription Entitlement Service

Bentley CONNECT Licensing has now been renamed Subscription Entitlement Service. CONNECT Licensing was first implemented in the RAM Structural in v16.00. This licensing monitors current usage and, if an attempt is made to use a program or module for which there is no available license, the program will give a warning. Important information is given in the v16.00 Release Notes.

More information on CONNECT Licensing / Subscription Entitlement Service can be found at:

https://www.bentley.com/en/subscription-services-portal/subscription-entitlement-service

User and Administrator instructions can be found here:

https://communities.bentley.com/products/licensing/w/licensing__wiki/37813/subscription-entitlement-service-formerly-connect-licensing

and a short guide has been posted here:

https://communities.bentley.com/products/ram-staad/m/structural_analysis_and_design_gallery/273502

CONNECT License / Subscription Entitlement Service requires all users to sign-in in order to use any Bentley programs. If you do not already have a Bentley ID, go to http://www.bentley.com/profile and select the Sign Up Now link.

NOTE: If you haven’t done so already, before using any version 16.0 or newer, the person at your company that has the role of Administrator for the Bentley products must configure the license so that it gives the overuse warnings. Otherwise, by default no warnings will be given. Instructions can be found here:

https://communities.bentley.com/products/licensing/w/licensing__wiki/38540/1---subscription-entitlement-service-for-administrators-getting-started

Review all of the information, but in particular, note the section on Entitlement Management, and in that document note the instructions on License Alerting. Generally, for License Alerting you will want to Enable Alerts, and then input the number of licenses that you own for the particular product.

CONNECT Licensing / Subscription Entitlement Service is revolutionary. It warns you against incidental overuse of the program, but when you have a temporary heavier work load it allows you to intentionally use more licenses than you own, at a fraction of the cost of purchasing an additional copy. Subscription Entitlement Service gives you the information you need to control usage and make those decisions.

Bentley CONNECT

In addition to providing the overuse warning described above, Bentley CONNECT offers several benefits. Listed here are three key features:

CONNECT Advisor

CONNECT Advisor provides links to pertinent articles, short training videos, courses and webinars. It can be accessed by selecting the Bentley Cloud Services – CONNECT Advisor command in the RAM Manager, or by selecting the CONNECT Advisor icon from the tool bar in any of the modules.

CONNECT Center

When you sign in to your Bentley account you now have easy access to CONNECT Center. This personalized portal gives you access to Usage reports, site configuration information, downloads, and Learning information on webinars, seminars and events, and includes a transcript listing the Bentley courses that you have completed. Your personal portal also lists your recent projects with a portal into analytics on that project. CONNECT Center can be accessed by selecting the Bentley Cloud Services – CONNECT Center command or by selecting the Sign In command in the upper right corner of the RAM Manager screen.

CONNECTED Projects

All of Bentley’s CONNECT Edition programs, including RAM Structural System, allow models to be associated with a project. Multiple models, from any of the Bentley products, can be associated with a given project. This simplifies the process of keeping track of work done for a project, and will enable analytics to be performed and reported for the project.

A ProjectWise Projects portal enables you and your project teams to see project details required to evaluate team activity and understand project performance.

• View project activity by site, application and user
• Gain insights into the users who are working on your projects and their effort
• Register and manage your CONNECTED Projects
• Access ProjectWise Connection Services including ProjectWise Project Sharing, ProjectWise Project Performance Dashboards and ProjectWise Issue Resolution Administration

When a model is Saved in this version the program will ask for a Project to which the file is to be associated. Projects can be registered (created) from your Personal Portal, or from the Assign Project dialog by selecting the + Register Project command.

Appendix B

Product Licensing FAQ – RAM Structural System: Blocking Use of Modules and Programs

VERSIONS 17.00 AND NEWER

The RAM Structural System contains links to three related Bentley products, RAM SBeam, RAM Concept and RAM Connection, providing design interoperability. Each of those programs have their own licenses. It is possible for a client to have licenses for some programs but not for the others. Because of the ease with which these programs can be invoked, a method of restricting the use of each has been incorporated in order to prevent unwanted or inadvertent usage by an unsuspecting user from being logged against the licenses that the company actually owns.

Note that if you have installed CONNECT versions of these programs and have correctly set up the warnings on entitlements you will receive a warning if overuse is about to occur; you may find it advantageous to rely on these warnings rather than blocking their use entirely as described below.

RAM SBeam is invoked using the Process – Export to SBeam command in the Steel Beam module. RAM Concept and RAM Connection are invoked using the tool bar buttons on the left of the RAM Manager screen:

or by using the Model or Design menu items:

If RAM SBeam, RAM Concept, or RAM Connection are not installed, they will not be available to be selected.

In RAM Manager, the Tools – Manage License Restrictions command opens the following dialog:

This provides a mechanism for the user to prevent a program from being inadvertently executed. When the RAM Structural System is first installed all of these options are selected. It is important therefore to execute this command and deselect any links for which the user wants to restrict access.

To prevent a program link from being executed, deselect that item.

If a link is deselected here and that link is subsequently invoked, the following dialog appears:

If Allow is selected the program will open, and usage will be logged. If Cancel is selected the program will not open and no usage will be logged. Settings opens the previous command, allowing the user to modify the selections of the allowed programs.

Note that there is also a link to Bentley’s ProjectWise for project management. It is available through the File – ProjectWise command. Its use is not restricted through the Tools – Manage License Restrictions command described above. It should only be invoked if you have a license for it.

VERSIONS 14.07 Through 16.01

The RAM Structural System is composed of several modules, each of which has their own license. The program also contains links to two related Bentley products, RAM Concept and RAM Connection, providing design interoperability, as well as a link to Bentley’s ProjectWise for project management. Each of those programs also have their own licenses. It is possible to have several licenses of one or more modules, and few or no licenses of other modules. Because of the ease with which these various modules and programs can be invoked, a method of restricting the use of each has been incorporated in order to prevent unwanted or inadvertent usage by an unsuspecting user from being logged against the licenses that the company actually owns.

These modules are invoked using the tool bar buttons on the left of the RAM Manager screen:

or by using the Model or Design menu items:

If RAM Concept or RAM Connection are not installed, they will not be available to be selected.

There is no license associated with RAM Manager, so no usage data is logged against it, but usage data is logged against each of the other modules as soon as they are invoked.

In RAM Manager, the Tools – Manage License Restrictions command opens the following dialog:

This provides a mechanism for the user to prevent a module from being inadvertently executed. When the program is first installed all of these options are selected. It is important therefore to execute this command and deselect any modules or links for which the user wants to restrict access.

To prevent a module or program link from being executed, deselect that item.

If a module is deselected here and that module or link is subsequently invoked, the following dialog appears:

If Allow is selected the module will open, and usage will be logged. If Cancel is selected the module will not open and no usage will be logged. Settings opens the previous command, allowing the user to modify the selections of the allowed modules.

Note that there is also a link to Bentley’s ProjectWise for project management. It is available through the File – ProjectWise command. Its use is not restricted through the Tools – Manage License Restrictions command described above. It should only be invoked if you have a license for it.

VERSIONS 14.06 AND EARLIER

Versions prior to V14.07 lacked the ability to manage these license restrictions, restrictions could only be achieved by deleting the module from the installation Prog directory. If you are using an earlier version and want to prevent use of a module, delete the file(s) listed here for the module to be prevented:

Problem Description

After installing RAM Structural System version 17 or later and signing into the Bentley Connection Client, the Ram Modeler module fails to open for a new or existing file. When clicking the button or menu option the cursor spins briefly, but nothing happens.

Details

*This problem mostly affect machines running Windows 7 (x64) but may also affect Windows 10 machines. Other modules like Ram Frame seem to work fine for existing files, but the Modeler does not start or launch.

Solution

We believe the problem relates to some incompatibility in the shared Microsoft components included in the Microsoft .NET Framework, SWL Server Compact Edition or Visual C++ Redistributables. To solve the problem follow these steps after creating a Windows Restore Point. We are looking into less invasive ways to restore functionality, but Windows 7 will not be supported much longer. 

1. Close all applications.
2. Uninstall RAM Structural System.
3. Uninstall Microsoft SQL Server Compact 4.0 x64.
4. Uninstall Microsoft Visual C++ Redistributables from 2015 through 2017.
5. Reinstall RAM Structural System. The RAM Structural System install process will reinstall the 2 Microsoft programs that were removed in the previous steps.

See Also

[[RAM Manager fails to open on 64-bit OS]]

RAMSS Files FAQ

RAM SS File-Open Troubleshooting [TN]

Ram Modeler license is disabled.

The Advanced Analysis Plus Engine license for STAAD.Pro brings with it the following advantages :

1. Memory efficient eigensolution method like Arnoldi/Lanczos for solving large scale eigen problems
2. Load dependent Ritz Vector for efficiently extracting relevant modes for fast and accurate calculation of structural responses. This is particularly useful for large models where huge number of modes has to be extracted to get adequate mass participation.
3. Geometric Non-linear Analysis
4. Pushover Analysis
5. Steady State Analysis
6. Buckling Analysis by eignesolution with ability to plot the buckling mode shapes 
7. Advanced Non Linear Cable Analysis
8. Floor Response Spectrum
9. Access to full capabilities of the STAAD Advanced Concrete Design (RCDC)

In STAAD.Pro CONNECT Edition, you must configure your license to use STAAD.Pro Advanced feature as shown here. 

In case you do not get the 'Welcome to STAAD.Pro CONNECT Edition Licensing' dialog box, since you have turned off the 'Display this dialog on startup', you can bring it back. Open STAAD.Pro -> click on 'Configure' -> 'Options', check the box 'Show Licensing Dialog'.

Within STAAD.pro SELECT series 6, the user must specifically request the use of the Advanced Analysis Plus Engine option on the start screen:

Otherwise, when attempting to run one of the Advanced Analysis options the following type of warning will appear:

See Also

[[Configure STAAD.Pro CONNECT edition for Advanced Analysis]]

[[SELECTsupport TechNotes and FAQs]]

The TechNotes and FAQs in this section cover various topics that pertain to the Advanced Analysis option within STAAD.pro. Use the navigation tree on the left to browse.

[[What is STAAD.Pro Advanced ?]]

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) 1997-2020 Bentley Solutions Center

STAAD.Pro CONNECT Edition,

Version 22

• CE V22 Update 5 (current release)
• CE V22 Update 4
• CE V22 Update 3
• CE V22 Update 2
• CE V22 Update 1
• CE Version 22
  

Version 21

• CE Update 3Build 21.03.00.146 (26 September 2018)
  
• CE Update 2 Build 21.00.02.43 (29 May 2018)
• CE Update 2 Build 21.00.02.30 (02 March 2018)
• CE Update 1 Build 21.00.01.12 (10 November 2017)
• CONNECT Edition Build 21.00.00.57 (25 July 2017)

Generation V8i

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)

The World's #1 Structural Analysis and Design Software

STAAD.Pro is the professional's choice for steel, concrete, timber, aluminum and cold-formed steel design of low and high-rise buildings, culverts, petrochemical plants, tunnels, bridges, piles and much more!

STAAD.Pro is the premier FEM analysis and design tool for any type of project including towers, culverts, plants, bridges, stadiums, and marine structures. With an array of advanced analysis capabilities including linear static, response spectra, time history, cable, and pushover and non-linear analyses, STAAD.Pro provides your engineering team with a scalable solution that will meet the demands of your project every time.

Visit the STAAD.Pro product Page for additional information on this product.

STAAD.Pro is CONNECTED. Why CONNECT?

STAAD.Pro is ISM Enabled.

LEARN

View STAAD.Pro learning paths on Bentley's LEARNserver.

QuickStart for Structural Engineers using STAAD.Pro

• Modeling Structural Members
• Modeling Finite Elements

Modeling Structures in STAAD.Pro

• Assigning Properties to Structural Geometry
• Modeling Loads and Load Combinations
• Specifying Analysis Commands and Using the Post Processor
• Modeling Complex Structures

Designing Concrete Structures with STAAD.Pro

• Designing Concrete Structures using the Reinforced Concrete Designer
• Designing Concrete Structures using STAAD Advanced Concrete Design RCDC

Designing Steel Structures with STAAD.Pro

• Designing Steel Structures
• Designing Steel Structures for Deflection
• Optimizing Steel Structures
• Designing Steel Structures according to the AS 4100
• Designing Steel Structures according to the AS 4100

Generating Seismic Loads in STAAD.Pro

• Generating Seismic Loads using the Equivalent Lateral Force Procedure
• Generating Seismic Loads using the Modal Response Spectrum Procedure
• Generating Seismic Loads using the Seismic Response History Procedure

Generating Wind Loads in STAAD.Pro

• Generating Winds Loads for Building Structures
• Generating Wind Loads for Other Structures

View the Transitioning from V8i to CONNECT Edition learning path.

Download

You can download the latest version of STAAD.Pro from Bentley's Software Downloads.

STAAD.Pro is available under a Structural Enterprise License. Learn more.

Support

[[STAAD.Pro Support Solutions]]

Related

[[STAAD Foundation Advanced]], [[Microstran]], [[RAM Elements]]

The STAAD.Pro Support Solutions contain a collection of Frequently asked questions ( FAQs) and TechNotes on various topics related to STAAD.Pro. Please use the navigation tree on the left or the links below to browse

STAAD.Pro Known Issues

STAAD.Pro CONNECT Edition Known Issues

STAAD.Pro V8i Known Issues

STAAD.Pro Nuclear Features

STAAD.Pro Nuclear Features

Frequently Asked Questions ( FAQs )

STAAD.Pro Analysis Solutions

STAAD.Pro Design Solutions

STAAD.Pro General Solutions

STAAD.Pro General FAQ's

STAAD.Pro Import Export Solutions

STAAD.Pro Import Export FAQ's

STAAD.Pro Installation/Licensing Solutions

STAAD.Pro Miscellaneous Solutions

STAAD.Pro Miscellaneous FAQ's

STAAD.Pro Modeling Solutions

STAAD.Pro Developing the Model FAQ's

STAAD.Pro OpenSTAAD_Solutions

STAAD.Pro OpenSTAAD FAQ's

STAAD.Pro Postprocessing Solutions

STAAD.Pro Postprocessing FAQ's

STAAD.Pro Driver Download FAQ's

TechNotes

STAAD.Pro Technotes [TN]

STAAD.Pro Verification Documents