Comprehensive analysis and design of moment frames using DuraFuse connection technology are now available in the RAM Structural System. This document describes the use of this feature.

Modeling

Create the model as customary for any project using steel moment frames.  When assigning preliminary lateral beam and columns sizes in RAM Modeler or in RAM Frame, it is important to keep in mind the following rules:

1. For a two-sided DuraFuse connection, beam depths must be equal or have a difference in depth greater than 6” to accommodate installation of plates and bolts. This is required because for beams of equal depth, the continuity plates extend across both sides of the column. For beams of different depths, the continuity plates are separate. If there is not a large enough difference between the beam depths the plates will run into each other or the bolts can’t be installed. Minor differences in depth can be accommodated with shims, contact DuraFuse to verify.
2. To allow the placement of the cover plate on the column, the relationship of the width of the beam and the width of the column is governed by the following equation:

b_bf +  0.25 in  ≤ b_cf +  2t_cp

where:

            b_bf= width of the beam flange

            b_cf= width of the column flange

            t_cp = thickness of the cover plates

If the beam width exceeds this value it will be necessary to cope the beam flanges.

Criteria

In RAM Frame, the Criteria for these moment connections can be specified using the Criteria – DuraFuse command.

The connection properties are different for high seismic (inelastic) applications versus wind (elastic) and low seismic applications. Select the criteria that is appropriate for the moment frames.

Note that DuraFuse panel zone properties are built-in automatically and accounted for when DuraFuse is assigned as a moment connection; the options for Rigid End Zones in the Criteria – General command are ignored.

Assign

In RAM Frame, assign the moment connection type using the Assign – Beams – Frame Beam Connection Types command.

The DuraFuse connection can be assigned to one or both ends of the beam; select the desired option. Generally, the Frame beams will have the DuraFuse connection on both ends, but in some cases it might be desired to pin one end of the beam and assign the DuraFuse moment connection on the other.

The connection can be assigned selectively with the Single or Fence command, or to all of the Frame beams with the All command.

The DuraFuse connection can be assigned to cantilever members when the cantilevers are modeled as Stub cantilevers. The DuraFuse connection is incompatible with cantilevers modeled as Extensions.

Once the beam ends have been assigned, RAM Frame will display the DuraFuse moment connection symbolically as shown:

The Assign – Columns – DuraFuse Parameters command can be used to assign cover plate dimensions and beam stiffness modifiers and stiffened regions. This command is not necessary, the program will automatically determine the appropriate values, and should only be used if directed by the engineers at DuraFuse. There may be circumstances where a nonstandard configuration results in a more economical design; this is unusual, but this command gives DuraFuse the ability to instruct engineers to change those parameters.

Analysis

When the Analysis is performed, the appropriate DuraFuse connection criteria properties are applied accordingly. Certain checks on sizes are performed to ensure compatible sizes are assigned to the frames. Some sizes are not permitted; if such a size has been assigned the program will display the following error:

Note that the analysis will proceed, but it should not be considered valid.

If the beams on either side of a joint are close in depth but not the same depth, a warning is displayed indicating that shims will be required. This condition is allowed but should be avoided if possible:

If the beam width exceeds the relationship defined previously, a warning is displayed indicating that the beam flange will need to be coped. This condition should be avoided if possible:

The Member Forces report for beams has been enhanced to identify that it has a DuraFuse connection, along with information about the member stiffness:

The report for columns includes the cover plate information, the panel zone spring stiffness, and the column stiffness multiplier:

A new section has been added to the Frame Takeoff report to include the cover plate weight of the DuraFuse connection:

Steel – Standard Provisions

The design moment and shear for the beams are taken at the face of the column. The unbraced length of the beam is measured from face of column to face of column.

The design moment and shear for the columns are taken at the face (top and bottom edges) of the cover plate.  The unbraced length (both x and y) is taken as the column height, not reduced by the connection depth.

For the connection itself, only the cover plate is designed; the design of the fuse plates, top plates, continuity plates and shear tabs are provided by DuraFuse Frames (https://durafuseframes.com). No Joint checks are performed in Standard Provisions mode.

Steel – Seismic Provisions

In the Steel – Seismic Provisions mode the seismic provision requirements for AISC 341-10 and -16 ASD and LRFD have been implemented for DuraFuse connections. Select one of those codes in the Criteria – Codes command.

It is necessary to assign a frame type to each member, used by the program to determine which seismic provisions are pertinent. This is done using the Assign – Frame Type command. Select either Special Moment Resisting Frame or Ordinary Moment Resisting Frame as appropriate. This assignment must be consistent with the methodology selected in the Criteria – DuraFuse command, as explained above. If the frame type is not consistent with the methodology the members will be indicated as failing; the following error message will be given in the View/Update command:

The Frame Type assignment on each member can be displayed by selecting the Frame Type labels option on the Frame Beam and Frame Column tabs in the View – Members command. The text on the display should show SMRF or OMRF.

Select the Process – Member Code Check command to have the code check performed on all of the members, and select the Process – Member View/Update command to select and view the results for an individual member.

Select the Process – Joint Code Check command to have the code check performed on all of the joints and select the Process – Joint View/Update command to select and view the results for an individual member.

The Seismic Provisions Member Code Check and Joint Code Check reports show the results of all the checks:

Note: Designs using the DuraFuse connection should be reviewed and verified by DuraFuse Frames. To assist in this process, upon completion of preliminary and/or final lateral designs using DuraFuse connection technology, users should send their RAM model (e.g. “filename.rss” file), including any customized beam, column or deck tables, to DuraFuse Frames (801-727-4060) at contact@durafuseframes.com for verification and validation of the computer model.  Upon completion of model review, DuraFuse Frames will provide structural drawings (notes and details), including stamped/signed calculations for each DuraFuse moment connection for the specific project.

Problem Description

When I am accessing Connection design within STAAD.pro CONNECT Edition, I am warned with a message, "This workflow is licensed with the RAM Connection license".

Solution

This is a warning message saying that with basic or Advanced STAAD.Pro license, following basic connection templates can be used.

• Basic DA BCF Bolted
• Basic DA BCF Welded
• Basic EP BCF Bolted
• Basic EP BCF Welded
• Basic DA BCW Welded
• Basic EP BCW Welded
• Basic SP BCF
• Basic SP BCW

In order to use all connection templates (including Smart and Gusset connections), a Structural Enterprise License or standalone RAM Connection license is required.

To activate the RAM Connection License, please follow steps as stated below.

Once you start the software, you will get the following dialog box.

Click on Configure License and you will get the following (this is available only if the check box is checked to show the dialog box on Startup).

Click on Accept and you can access the features of RAM Connection fully.

 if the check box has been unchecked to not show the dialog box on Startup, you can bring it back from STAAD.Pro startup page as shown below.

As stated, check the box for RAM Connection. You will get the following dialog box stating that you must restart STAAD.Pro to take the license change in effect.

P.S. Note the information in the initial License Configuration dialog box "Depending on the licenses your organization owns and product usage, this may incur additional software usage charges". If you are not sure about what licenses your company owns or if it is okay to use it and pay later, please check with your concerned department.

See Also

Error getting a RAM Connection License

Tips for Using RAM Connection within STAAD.Pro [TN].

[[How do I prevent access to the RAM Connection tab within STAAD.Pro?]]

This article guides users to a list of design codes supported within STAAD.Pro along with the licenses that include them.

Background

STAAD.Pro supports several international design codes. These design codes are grouped together and supported with specific design code licenses. However, the groupings are not always obvious. Fortunately, STAAD.Pro includes in the documentation a list of supported codes along with the licenses that cover them.

Steps to Accomplish

1. Select from the Windows Start menu:
   All Programs -> Bentley Engineering -> STAAD.Pro V8i -> STAAD.Pro Online Documentation

2. In the window that appears, click the Contents tab on the left pane.

3. Expand the first topic titled Welcome to STAAD.Pro V8i.

4. Select the listing titled Available Design Codes in STAAD.Pro.

In the latest STAAD.Pro CONNECT Edition, you can find the documentation at the location below

See Also

[[STAAD.Pro TechNotes and FAQs]]

Release Date:  Coming Soon

Release Name: Structural Synchronizer CONNECT Edition V11 Update 1 (Patch 2)

Release Version: 11.01.02.09

Download Instructions

After signing into the CONNECTION Center, select Software Downloads under My Services. Once on the Software Fulfillment page, the installer can be located by performing a search on “Structural Synchronizer”. Direct Software Downloads link.

Subscription Entitlement Service (SES) 

This product version utilizes Subscription Entitlement Service, which is not supported by SELECT activation key(s). SES is a free service, featuring new behavior to enhance your organization’s user administration and security with mandatory user sign-in via CONNECTION Client to access the application. If you are already signed in to the CONNECTION Client, you have met this prerequisite. If you have not, please refer to the Administrator's Resource Center and/or contact your administrator for assistance in the registration and sign-in process. 

Bug Fixes

This patch release temporarily returns x86 support to Structural Synchronizer to cater for incompatibility with STAAD Foundation Advance.

ApiInternal Delivery fix for forthcoming ProStructures CE Update 5. 

Localised versions of STAAD.Pro are available from the downloads centre in various languages. In order to successfully install and operate these versions the following requirements should be met/

The computer should be running a licensed Windows 10 or Windows 8.1 operating system, with 64-bit system architecture. For more specific detailed information about the requirements of the operating systems, refer to Installation Requirements section of STAAD.Pro ReadMe document, available from: https://docs.bentley.com/LiveContent/web/STAAD.Pro%20Readme-v6/en/GUID-5831209F-DA5C-460C-8599-D800FC08B120.html

The following additional requirements or pre-requisites also apply for localized editions of STAAD.Pro .

• Installation of Language Packs
  • Installation of the Windows language pack (for a language in which STAAD.Pro is localized) – is a pre-requisite to work with a localized edition of STAAD.Pro. For example, Russian edition of STAAD.Pro is supposed to work only if Russian Language Pack is pre-installed
  • Steps for setting up of language pack for a specific language is described in Microsoft documentation: https://support.microsoft.com/en-in/help/14236/windows-language-packs.

• Setting up of System Locale
  • Appropriate language (system Locale) for non-Unicode programs should be selected. For example – Russian edition of STAAD.Pro should work only if system locale is selected as Russian(Russia).
  • For more information on System Locale and making changes in it, please follow the link: https://docs.microsoft.com/en-us/windows-hardware/customize/desktop/unattend/microsoft-windows-international-core-winpe-systemlocale

How does STAAD "direct" a spring to determine if it is in compression or tension?

In view of the above, how should one specified radially directed springs located around a circular tunnel or pipe and designate them as "compression" only in the physical sense of the term?

For the purpose of defining the sense of the force in the SPRING TENSION/SPRING COMPRESSION facility, the following rules are adopted in STAAD :

A support reaction force is considered TENSILE if it is opposite to the positive direction of the axis under consideration. Another way of putting it is that, for this condition, the displacement along that axis of the support node is in the same direction as the positive direction of that axis.

A support reaction force is considered COMPRESSIVE if it is along the positive direction of the axis under consideration. Another way of putting it is that, for this condition, the displacement along that axis of the support node is in the direction opposite to the positive direction of that axis.

These rules are applicable for global axis supports, as well as inclined axis supports.

Hence, use the center of the circular pipe as the REFERENCE POINT for the INCLINED supports. The local X axis for the inclined supports will then point from the perimeter towards the center of the circle. The supports around the circumference can then be assigned COMPRESSION only springs. .

Click on below link for Design steps and Validation problem on Design of Shear Wall with Boundary wall as per IS 13920-2016

https://communities.bentley.com/products/ram-staad/m/structural_analysis_and_design_gallery/274509

ACI_318M_Validation sheets

1.  Beam Validation (Intermediate Frame)

B24_Design Calculation_Validation sheet

B24_Design calculation from RCDC

2.Beam Validation (Special Frame)

B16_Design Validation sheet

B16_Design calculation from RCDC

3. Column Validation (Intermediate Frame)

C4_7.88 to 9.08m_Design Calculation_Validation sheet

C4_7.88 to 9.08m Level_Design calculation from RCDC

4. Beam Crack width check

B22_Beam Crack Width Check

B22_Beam Crack Width Check_RCDC report

• Does RCDC design the irregular slab like L, T shapes and slab having more than four edges?
  • Yes. Rectangular and odd shaped slabs can be designed in RCDC. RCDC designs the two way and irregular slab based on yield line theory. For odd shaped slab RCDC considers the largest span as shorter direction for design. For Aspect ratio (L/B) RCDC considers the outer-most dimensions of the irregular slab. As per the aspect ratio of irregular slab it identifies whether the slab is one way or two way. For design using ACI, the two way and irregular slab are based on direct design method. For more information refer “Technical Discussion” of slab from help Content.

• For square/rectangular panels of slab, can RCDC transfer the load to two adjacent edges (beams) only as per user choice? 
  • No. RCDC designs the slab as per relevant clauses and based on explanation provided in relevant codes. RCDC automatically identifies continuity based on the edge conditions. User can change end conditions as per requirements. User can change the type of slab like one way or two way as per choice. RCDC will design the slab accordingly. For more information refer “Technical Discussion” of slab from help Content.

• RCDC is considering some slabs as cut-outs but actually we have modelled those slab instead of cut-outs in E-tabs.
  • In E-tabs, sometimes user models single membrane or shell for many number of slabs combined in one large entity. Thus in this case, individual slabs bounded by beams can’t be read by RCDC. For more information refer “Slab auto-detection” of slab from help Content.

• Tensile factor for deflection of slabs is limited to 2.0 in IS 456 but RCDC provides value 2.26 in the design calculations. Please clarify.
  • Calculation of tensile factor is based on the formulation available in SP24 clause 22.2.1. IS 456 has provided the graph up to value 2.0 but it is not restricted as far as formulation is concerned. Higher values can be considered in design to control the deflection.

• Which method is used for Two way slab design in ACI 318 (Metric and English) code available in RCDC?

  • RCDC has used Direct design method available in ACI code.

I am doing an analysis with response spectrum loads. I also need to define compression only springs to simulate soil support. How can I do this ?

Response Spectrum loading, due to it's very nature, does not lend itself to any iterative type analysis ( Tension/compression, Pdelta etc.). So the short answer to the question is, response spectrum loading cannot be used in conjunction with compression only springs.

However you may do a couple of things. 

First option is to define the support springs without compression only attribute to analyze the response spectrum cases and other primary cases ( live load, equipment load etc.). Use PERFORM ANALYSIS and CHANGE after that. Subsequently re-define the support springs with compression only attribute followed by REPEAT LOADs to combine the primary cases. For combining the response spectrum cases with other loads, you still have to use LOAD COMBINATION. Once all REPEAT LOADs and LOAD COMBINATIONs ( for response spectrum combos only ) are defined, follow it up with another PERFORM ANALYSIS and CHANGE. 

Other option is to use equivalent static seismic loads to represent seismic loads as opposed to using a response spectrum load in which case you would be able to use REPEAT LOADs and compression only springs to combine gravity+seismic loads. You may scale the equivalent static seismic loads by the ratio of the base shears ( in other words use a multiplying factor equal to response spectrum base shear/equivalent static base shear).       

***UNDER CONSTRUCTION***

The definition of center of rigidity (CR) is as follows:

The center of rigidity is a point at a particular story as the location of application of lateral load at that point will not produce rotation of that story.

The above definition is valid when slab is modelled as a rigid diaphragm. A Diaphragm Constraint causes all of its constrained joints to move together as a planar diaphragm that is rigid against membrane deformation. For semi-rigid diaphragm, the inplane deformation on a floor points could be different due to inplane-deformation of slab. Therefore, there is no unique solution to center of rigidity i.e. the Center of rigidity is indeterminate quantity.

The center of rigidity is just a reporting item. The inherent eccentricity due to change in mass centroid and stiffness centroid is automatically included in the analysis regardless the choice of diaphragm. Therefore, the reported value for center of rigidity for semi-rigid diaphragm has no meaning and this reported CR does not affect the analysis results.

Center of rigidity is the stiffness centroid within a floor-diaphragm plan. When the center of rigidity is subjected to lateral loading, the floor diaphragm will experience only translational displacement. Other levels are free to translate and rotate since behavior is coupled both in plan and along height. As a function of structural properties, center of rigidity is independent of loading. Certain building codes require center of rigidity for multistory-building design-eccentricity requirements.

For a given floor-diaphragm, CR is calculated through the following process in case of the floor defined as Rigid Diaphragm:-

Case-1: applies a global-X unit load to an arbitrary point such that the diaphragm rotates RXY

Case-2: applies a global-Z unit load to an arbitrary point such that the diaphragm rotates RYZ

Case-3: applies a unit moment about global-Y causing rotation RYY

If there are “N” no. of rigid diaphragms present in the model, there will be “3N” no. of load cases generated for which static analysis will be performed.

Center of Rigidity (X, Z) is then computed as:

X= RYZ / RYY

Z = - RXY / RYY

In STAAD, the unit loads are applied at CM

The global coordinates of CR at each floor is given by (CRx, CRy and CRy), where CRx = CMx + X, CRy = CMy and CRz = CMz + Z

Where, centre of mass (CM) at each floor level and find its coordinates (CMx, CMy, and CMz)

NOTE: Center of rigidity is only applicable to rigid diaphragms because in-plane slab deformation is variable across laterally loaded semi-rigid diaphragms. During computation, an arbitrary coordinate is selected and loaded, and then center of rigidity is derived, as a function of stiffness, according to the displacement at this specific point. If a diaphragm constraint is not applied, displacement at any point will also depend upon variable local membrane deformation. As a result, no unique solution is available for center of rigidity since formulation assumes that all joints translate together in planar motion.

• Can grid lines be imported from Auto-cad?
  • Grids cannot be imported from Auto-cad. For Staad files RCDC auto identifies the grids as per centre of columns and for E-tabs it reads if they are available. User can view or edit the grids label and location. For more information refer topic “Grid Lines” from help Content.

• Can all design calculation reports exported in Excel format?
  • Design reports are generated in platform independent html format so as to facilitate the user to open it in any software. User can open the HTML File in excel and word.

• How to freeze drawing style settings in all newly opened RCDC file?
  • Before starting project, settings for drawings style can be modify/update for all element. Please refer help for more details.

• The load combinations considered for regular/irregular building in sizing are with factor 1 for all load cases. Can this factor be an input?
  • Factor can’t be an input, as for sizing of footing/Pile-cap different factors are to be considered for dead, live and other load cases. However, user can create his own load combination templates by using ‘Add Load Combination’ option and creating a new template. User also can add or remove load combinations as per requirements. For more information refer Topic “Load and Load combinations” from help Content.

• While trying to design RCC beam using ACI 318, exporting the data from ETABS in FPS (foot-pound-second) system, but the data that is being reflected in RCDC is in MKS (meter-kilogram-second) system.
  • RCDC refers to ACI-318M-2011 (metric units) code. If data is exported in feet and inches RCDC internally changes the forces in to kN and m. Working environment in RCDC is in MKS units. User can provide the input data in kN and M unit for RCDC. The output can be generated in inches unit. Refer ‘Style Manager’ in RCDC for the same.

• Is the Vertical axis of STAAD and RCDC Same?

  At the time of importing the loads in RCDC if we give X direction to Earthquake X and Z direction to earthquake Z, then it will convert it in its relevant direction?

  • RCDC is a design software and imports the analysis forces from STAAD for design. There is no specific axis of the RCDC.

    example: for column design, RCDC get the forces along major and minor axis. whatever the load cases defined in analysis, RCDC get the forces for local member and it designs the member. 

    Defining direction for Eq forces i.e. X and Z, it just a load case type. it will just help to create load combinations as per load type. if Eq-z is available in Analysis and it is defined as Eq-Y then it doesn't affect the design forces of the member. Forces for that load case will remains same. EQ-Y is just a nomenclature for that load case.

• 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.

• 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

• 1. How the effective self-weight of the footing is calculated?
  • Effective self-weight of footing is calculated as additional load of footing volume with respect to difference in density of concrete and soil. For more information refer “Technical discussion” of footing from help Content.

• 2. For calculation of two way (punching) shear, footing self-weight is not added to axial load.
  • Concept of Footing punching shear criteria is column punches in the footing. Load from the column punches the column in footing. Self-weight of footing, overburden load do not participate in punching of column as it is a uniformly distributed load, thus it is not considered in design. For more information refer “Technical discussion” of footing from help Content.

• 3. As per design, required reinforcement is 1478/1528 sqmm along L/B direction. Provided reinforcement is T12@175 mm which amounts to 1453 sqmm only for 2.25 m width of footing, whereas the calculation report shows Ast provided as 1583sqmm. Please clarify.
  • Width = 2250 mm Ast required = 1478 sqmm Reinforcement provided = T12@175 mm In RCDC the number of bars required are calculated and spacing is calculated. While presenting the spacing rounded to 5 mm. In this example, number of bars as per spacing would be calculated as below – (2250 / 175 = 12.86 which is 13 spaces). Hence number of bars would be 14. Thus actual Ast-provided would be (14x113.097 = 1584) 1584 sqmm which is more than required.

• 4. Please clarify the footing type “on raft” given in RCDC.
  • RCDC designs the isolated footings. The purpose of this options is to maintain the same thickness of first step for all footings if all footing are connected by common raft. This type of footing mostly use in the basement structures. The concept of this type of footing is similar to stepped footing.

• 5. How is the volume of trapezoidal footing calculated in RCDC?
  • RCDC calculates the weight of trapezoidal footing as per following formulations, Self-wt. of footing Volume of footing = ((L*B*D) + ((((L*B) + (Lt*Bt))/2)*(D-d))/1000^3 Where, L= Length of footing B= Width of footing D= Depth of footing Lt= Length of footing top Bt= Width of footing top d= depth of sloping area

• 1. For which load combination, number of piles in the pile cap design are decided?
  • Number of piles are decided as per maximum load on one pile and group of piles for all service load combinations. Checks for maximum load on one pile and group of piles are added in design calculation report. Maximum Load on one pile and group of piles for each load combinations are added in the Pile Capacity Check & Sizing report. For more information refer “Technical discussion” of Pile-cap from help Content.

• 2. Kindly clarify whether Development Length in Compression (Ld) is considered, while arriving the depth of Foundation or a Pile Cap.
  • For footing and pile-cap RCDC does not considered the “Ld” of the column reinforcement for minimum depth. Column design is an independent activity thus information of column reinforcement is not available for pile-cap design. User can provide minimum pile-cap depth available in general settings as per Ld requirement. Also if required each pile-cap can be redesigned with required minimum depth.

• 3. Does 25% increment for group of pile is applicable in lateral load cases?
  • As per code 25% increment is applicable for one pile for lateral load. For individual pile in a group of piles, the check is performed for 125% of pile capacity. However for group of piles, the 25% increment can’t be applied. For more information refer “Technical discussion” of Pile-cap from help Content.

Currently, the AISC Steel Construction Manual lists 283 wide flange shapes in Table 1-1. Historically there were no standard dimensions, and different steel producers produced their own sets of shapes. Over time as producers merged or went out of business these various shapes were consolidated into the list we have today. So the shapes we use today didn’t necessarily come about because of a concerted effort to produce the most efficient and economical set of shapes, in many cases it was just happenstance. AISC, in cooperation with the steel producers, is studying the idea of rationalizing the shapes that are produced, and possibly even reducing that number (for example, perhaps rather than producing two shapes that are roughly the same whose weight only varies by a few pounds, produce a single shape that is something in between those two). This would have several benefits: the shape cross-sections would be better proportioned, and therefore geometrically more suitable for their purposes; Engineers would have fewer sizes that would need to be considered when optimizing the design of a structure; there would tend to be fewer different sizes on a project, making the project more economical because of the grouped quantities of shapes; service centers would not have to stock as many different shapes; and producers wouldn’t have to produce rarely-used shapes. This would all have the tendency of simplifying the design, detailing, supply, and erection of the members, thereby making steel structures more economical. And the shapes that are specified would be more likely to be readily available, without impacting the schedule.

As part of this study, AISC is trying to determine how frequently the various shapes are specified. This will help provide a basis for determining which shapes are rarely used, and which can be rationalized with other very similar shapes. Because of the broad reach that the RAM Structural System has in the steel building industry, AISC approached us to see if we could help compile this data. So I am asking for your help. We are asking that you send us the Takeoff Reports from your projects. There are three such reports: Gravity Beam Design Takeoff (from the Steel Beam module), Gravity Column Design Takeoff (from the Steel Column module), and Frame Takeoff (from the RAM Frame module).

In order for us to manage the data we need the reports sent as text files.

Do the following:

1. In the Reports menu, select the Text File option:

2. Select the Reports – Takeoff command.

3. Enter a filename. It would be helpful if the name of the file started with “Beam”, “Column”, or “Frame”, depending on which module it came from.

4. Save the file in a convenient location.

5. Do this for each of the three Takeoff reports.

6. Attach these Takeoff files to an email. In the Subject Line, put “Takeoff Study”. Send the email to me at allen.adams@bentley.com. Multiple files from multiple projects can be sent with each email, they don’t need to be emailed separately.

Note that by sending me these files you are granting us permission to use the data. But also note that there is nothing in these files that reveals anything about your project other than steel quantities and floor areas. So the confidentiality of the project is safeguarded.

Please only send these files from models that represent the final or nearly final design (not from early models with preliminary sizes), we want to know what is being built out there. Please send us the data, no matter how large or small the project.

We appreciate your time and your contribution to this study!

Description

I have installed Structural Synchronizer successfully in my machine; when I try to access it from RAM Structural System, it says it is not installed.

Explanation:

There could be two reasons behind it,

• 64 bit of Structural Synchronizer and 32 bit of RAM Structural System is installed in the machine
• Structural Synchronizer has been installed, but there is a version mismatch with the one that is supported by the specific version of RAM Structural System

Solution

Please note that Structural Synchronizer is the engine that makes ISM work. 

1) In case there is a mismatch in Structural Synchronizer (64bit) and RAM Structural System (32 bit), download the 64 bit version of RAM Structural System by following the steps stated in the link below. Starting with version 15.05.00.00, only 64 bit versions are available. 

Software Download Instructions

2) If you have installed Structural Synchronizer (64 bit) and RAM Structural System (64 bit) and the ISM says not installed, then there is a version mismatch between RAM Structural System and Structural Synchronizer.

Uninstall Structural Synchronizer from the machine. Download and install the latest version of RAM Structural System and Structural Synchronizer.

They can be downloaded from Software Downloads.

See Also

How can I find the ISM installer?

ISM is showing Not Installed for Ram SS 17.00

Problem Description

When assigning a CBB Gusset connection to an existing joint with a 90 degree column orientation, an error message saying "Object reference not set to an instance of an object" occurs. After closing the error box, none of the other CBB joint thumbnails are displayed.

Also affects Ram Connection for Ram Elements or Ram Connection for Ram Structural System.

Reason

Programming error.

Solution

Fixed in version 13.02.00.19 (available from Technical Support through a Service Request), and in the official release 13.02.01.25 or therafter. 

See Also

File corruption after conversion - Access Violation

Software Download Instructions