How can I evaluate an existing composite beam?

Using the Process - View/Update command, select the beam in the model. Change the selected member size, set the stud number to the desired value and click Analyze. Then click Update Database when finished.

If the existing stud count is insufficient to achieve 25% composite action (or the code minimum), go to Criteria - Stud Criteria and for the last option, select to "Use Composite section properties".

Note: the program will never optimize a member with less than 25% composite action (US codes), but you can reduce the number of studs and evaluate this way.

The most common cause for composite beams that cannot achieve the minimum composite action is when the beam is acutely skewed to the angle of the deck. Thus, only a few flutes will cross the beam (or segment of the beam) limiting the total number of studs possible. Angles less than 15 degrees are treated as parallel to the beam, but the trigonometry of deck angles between 15 and 90 degrees to the beam are considered. In cases where the deck is to be split or crushed along a specific beam allowing for other spacing of studs, use the Assign - Ignore Rib Spacing command.

Can I lock or freeze all the beam designs?

Yes, once the designs are correct, use the Process - Freeze Design command to freeze the designs for some or all of the beams. This is often a good idea once construction documents for the project have been released.

The same command can be found in other modules, too.

Can I set a maximum interaction ratio other than 1.0, like 0.95?

Regretfully not for steel beams, only for open web steel joists. For steel beams, the best thing to do is visually inspect the interaction colors and identify any beams that are too close to the max interaction ratio for your comfort and then Update those one-by-one. 

Another alternative is to pad the loads slightly or reduce the beam Fy, run the design and freeze all beams, then reset the loads and run it again. This approach would effectively over design the beams not only for strength, but for deflection as well.

Why are my composite beams being designed as non-composite members?

Beams that have been defined as composite, may be designed as non-composite for the following reasons:

• Non-composite deck
• Opening or exposed beam 
• Cantilever 
• No load

Non-composite deck: Composite beams will be designed as non-composite if the deck on both sides of the beam is non-composite for any portion of the beam span.

Opening or exposed beam: A beam that spans through an opening or penetration or for which there is a portion supporting no deck, such as an inset beam, will be designed as non-composite. Some times it is desired to design inset beams as composite. In order to do this, you can add a short beam from the column to the perimeter beams at an angle (say 45 degrees). Then define the slab edge so that it follows along these short beams, going out and around the perimeter column. That way, the entire beam is covered by the deck and it can be designed as composite (see below).

Cantilever: If the negative bending moment at the support of a cantilever beam is greater than twice the positive moment of the back span, the beam will be designed as non-composite. When a cantilever beam is designed compositely, the program determined number of studs should all be placed in the back-span. Note, for some codes no negative moment is allowed for composite beam design and in those cases a cantilever will always result in non-composite design.

No Load: If there is no load on the beam it will be designed as non-composite. This is sometimes a result of accidentally orienting the deck in the wrong direction such that the infill beams are not loaded.

Note: once a beam has been designed as a non-composite member, the composite flag for the beam will be set to non-composite. You have to go back to the Modeler and use the Layout - Beams - Change properties command to turn it back into a composite member.

How can I limit the effective width considered for a composite beam.

In composite design the program calculates the effective width (beff) automatically based on the geometry of the framing and decking. If you need to limit the width you can place a slab penetration on one or both sides of the beam in the Modeler. The size of the penetration does not matter since penetrations have no effect on the surface loading, so I recommend something fairly small, maybe 1' square, placed near the mid-span of the beam. The distance from the edge of the penetration to the beam center line will then be used for the effective flange width on that side. 

Can I turn off the pattern loading on beam cantilevers?

Regretfully, not at this time. Live loads are always considered to act on the cantilever only, on the back-span only, or on the entire beam, whichever condition provides the most conservative design for shear, bending and deflection. This is true even for snow loads which can be overly conservative. [[RAM Steel Beam Pattern Loading]] has further details.

Only dead loads are not subject to patterning.

Can I customize the load combinations used in RAM Steel Beam?

Regretfully, not at this time. The load combinations used in RAM Steel are internal to the program and cannot be modified.

See Section 10.3.11 in the RAM Steel Beam Manual for a list of combinations used for each design code.

Note that floor live load and snow or roof live loads are combined and applied as a single live load. Some building codes, such as IBC, permit a reduction (0.75 factor) for combinations including two or more transient loads. RAM Steel uses the combination 1.0 DL + 1.0 LL (effectively, 1.0 DL + 1.0 LL + 1.0 SL). Using the reduction noted above, a load combination of 1.0 DL + 0.75 LL + 0.75 SL is permitted. If the IBC is selected for the code for load combination generation in RAM Frame, 1.0 DL + 0.75 LL + 0.75 SL and not 1.0 DL + 1.0 LL + 1.0 SL. This can cause some design differences for beams designed in RAM Steel Beam versus RAM Frame. 

Can I override the unbraced length of a steel gravity beam?

In cases where you want the unbraced length to be reduced you can add brace points in the Modeler using Layout - Beams - Brace points. Alternatively adding additional short beams framing into the beam in question will brace the top and bottom flange at those locations. Use joists where you want only the top flange braced.

In cases where you want the program to use a longer unbraced length, for example where a beam is set higher than the deck in reality, set the Criteria - Design Criteria - Unbraced length so that neither deck perpendicular nor parallel to the beam braces the top flange. Since it's a global criteria it will affect all beams, however, so you might have to set the criteria this way and check the one beam, freeze the design, and then check the rest using the preferred criteria.

Alternatively, you could add a long penetration (Modeler - Layout - Slab - Slab Penetrations) along the beam covering most of the span.

How can I use a section that does not appear in the View/Update list?

The sections listed in the Steel Beam View/Update dialog box are based on those in the Steel Beam Design Table. See RAM Table Editing for details.

See Also

[[RAM SS - Steel Beam Deflection and Camber]]

[[Ram Steel Beam Unbraced Length]]

[[structural_analysis_and_design__wiki:RAMSS Design Fy or Py|RAMSS Design Fy or Py]]

Appendix A

Technology Preview – Analytical Insights

Icon

Description

Analytical Insights (AI) is a data analytics service for design engineering with the following objectives

• Automating and increasing breadth of QA/QC

• Practical engineering design with construction data

• Institutionalized lessons learned to reduce design risks

• Executive overview on design status and quality

To start the Analytical Insights Technology Preview, select the Bentley Cloud Services – Analytical Insights Technology Preview command.

AI enables you define custom engineering rules in addition to code prescribed rules for engineering design. AI also lets you merge construction data from various sources with the engineering model to offer create more practical designs.

In principle, AI implements the following workflow:

KPI stands for Key Performance Indicator.

An Engineering Manager can set up design rules online through the CONNECT portal. These rules will be shared across their entire organization. These rules specify properties of the structure along with permissible limits. For example, a rule might specify that the span to depth ratio for steel beams should not be less than 20.

An Engineer can upload a model from RAM Structural Systems to Analytical Insights by first exporting the RSS model to an ISM file format, via the ISM link, and then sending data to Analytical Insights through the AI Extractor.

Before launching Analytical Insights, a CONNECT project must be associated with the currently loaded RAM model (see chapter 4, "CONNECTED Project Association" for more information) and an ISM file must be created for the model (see chapter 3, “Integrated Structural Model (ISM) Link").

The AI Launcher will convert the ISM file to a cloud compatible format and then upload the model to Bentley CONNECT. After the upload completes, the AI launcher will invoke an internet browser session with the model link where you can set up design rules and perform KPI analyses.

CONNECT sign-in and CONNECT project assignment are requirements to utilize Analytical Insights.

• Learn more about Bentley CONNECT from here

• Learn more about sign-up information from here

You will find information on how to use Analytical Insights on the AI start page. Click the “Learn more about Analytical Insights” link to launch an interactive work flow diagram that explains the steps and results.

In future releases of Analytical Insights, the user will be able to compare a model with previous models present in an organization. The user will be able to apply filters like Type of Lateral Resistance, Year Built, Weights per Area, etc. and investigate design patterns and decisions made in previous projects.

Read more about Analytical Insights here.

How can I decouple or unlink a Ram Concept file that is part of a Ram Structural System file?

1. Open the Ram SS model in Ram Manager
2. Open the Design - Ram Concept window and note the Last saved in Concept time for the specific level of interest.
3. Navigate to the RAM SS working directory (default here: C:\ProgramData\Bentley\Engineering\RAM Structural System\Data\Working)
4. Locate the specific Concept file you want. The file name will be same as ram model with .cpt###E at the end. Check the saved time and compare to the information seen in Ram manager to make sure you have the right one.
5. Copy the file to the clipboard and paste a copy in another location outside of the working folder
6. Rename the file, changing the extension from .cpt###E to .cpt.
7. Then open the copy in Ram Concept normally.

How can I delete a Concept file inside of a RAM SS file so that I can start over?

1. Open the Ram SS model in Ram Manager
2. Open the Design - Ram Concept window and note the Last saved in Concept time for the specific level of interest.
3. Navigate to the RAM SS working directory (default here: C:\ProgramData\Bentley\Engineering\RAM Structural System\Data\Working)
4. Locate the specific Concept file you no longer want. The file name will be same as ram model with .cpt###E at the end. Check the saved time and compare to the information seen in Ram manager to make sure you have the right one.
5. Delete the file from the working folder
6. Restart the Design - Ram Concept command in Ram Manager and you should now be able to start over with that level.
7. Use the "Copy from existing Story data" option if you want to recover information from another story, otherwise check the settings and click OK.

When I open a Concept file that was previously linked to a Ram Structural System model I get a message that the link will be broken. How can it be fixed?

If the associated RAM SS model is deleted, renamed or moved then you will get a message indicating that the link must be broken:

This also happens if the files are transferred to another computer and no longer have the same relative directory paths.

The issue does not necessarily have to be fixed. If you know that the Concept data from RAM is current you could do nothing. You could not export updated column reactions back to RAM SS in this case, however.

To fix the issue, simply reimport the RAM SS file into Concept using File - Sync Ram Structural System - Import....

Then use the Merge option when presented:

Select the appropriate RAM Structural System model and story.

When importing be sure to uncheck any items that should not be updated. Typically we suggest not re-importing the slabs, beams or openings since those objects are often adjusted in Concept after the initial import.

See Also

RAM Concept-RAM Structural System Integration TN

Structural Product TechNotes And FAQs

RAM Concept has been used on projects of all sizes around the world. Below is a list of some notable structures on which the software played a key role in the structural design.

Shard at London Bridge Quarter, London, United Kingdom

https://www.bentley.com/~/asset/14/628.ashx

Marina Bay Sands Integrated Resort, Singapore

http://www.bentley.com/en-US/Products/RAM+Concept/Case+Studies.htm

Trump International Hotel & Tower, Waikiki, Hawaii

https://www.baseengr.com/images/uploads/01-news-publications/whitepaper/SE0912_PDH_01-small.pdf

Manchester Hilton, United Kingdom

http://ftp2.bentley.com/dist/collateral/Web/BEAwards07/Posters/Building_272.pdf

K2 Business Park, Russia

http://www.nxtbook.com/nxtbooks/bemagazine/vol6issue4/index.php?startid=29#/30

Problem Description

The COMPRESSION ONLY attribute is being removed from the ELASTIC MAT/PLATE MAT supports when saving using the GUI.

Steps to Reproduce

1. Open a file with ELASTIC or PLATE MAT support with the words PRINT COMPRESSION at the end.
2. Save the file using the graphic user interface or do a Save As
3. Note that the word COMPRESSION is deleted from the end of the command line.

Before Saving :

SUPPORTS

…

403 TO 433 ELASTIC MAT DIRECT YONLY SUBGRADE 12000 PRINT COMPRESSION

After saving the file using the GUI

SUPPORTS

…

403 TO 433 ELASTIC MAT DIRECT YONLY SUBGRADE 12000 PRINT

Workaround

It has been observed that if the PRINT command is not there, this problem does not happen. So as a temporary workaround please remove the PRINT command as shown next

SUPPORTS

…

403 TO 433 ELASTIC MAT DIRECT YONLY SUBGRADE 12000 COMPRESSION

Saving the file using the GUI or doing a Save As should work fine now.

Solution

Will be addressed in the STAAD.Pro Connect Edition expected in summer of 2017

See Also

The known issues in the release 20.07.11.82 are listed here

Warning : Design Code License is not Activated

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

Overview

Podium slabs are concrete transfer slabs supporting multiple levels of wood or steel framed superstructures above. This popular framing system can be analyzed and designed using RAM Structural System and RAM Concept. The purpose of this tech note is to discuss issues and common questions relating to the modeling and design of this system using these programs.

Modeling Options

Two common options for designing this type of structure include:

1. Use a two-stage analysis in which the upper portion and lower portion are designed as separate structures in RAM Structural System. See ASCE7 12.2.3.2 for details.

2. Model the entire structure in one model in RAM Structural System.

Regretfully, there is not an automated two-stage analysis feature in RAM Structural System. This means that loading from one model needs to be manually entered in the second. One possible work around:

1. Model and analyze the upper portion in RAM Structural System with a mat foundation.
2. Import the mat foundation into RAM Concept.
3. Add columns  to convert the model to an elevated slab.
4. Amplify imported loads to satisfy ASCE7 12.2.3.2.
5. Add lateral and additional gravity loads on lower portion in Concept.
6. Analyze and design.

With this approach, foundations will need to be designed manually using the analysis results from RAM Concept. There is not a way to import them into RAM Foundation for design. Also, the lateral analysis for the lower floor is done in RAM Concept. This will not work well if there are multiple concrete levels below the upper portion.

RAM Structural System Tips

In RAM Modeler, live load reduction percentages should be modeled manually for columns and walls supporting two-way decks. See the following web page for more information on using two-way decks in RAM Structural System:

RAM SS Two-Way Decks

in versions 14.07.00 to 15.01.00, the diaphragm at the podium level should be defined as a semirigid diaphragm so that the out-of-plane stiffness is considered when analyzing lateral load cases. When a two-way deck is defined as a rigid diaphragm, the out-of-plane stiffness is considered when analyzing gravity load cases but ignored when analyzing lateral load cases. Ignoring the out-of-plane stiffness can result in large displacements or instability errors for transfer levels. Starting with version 15.02, consideration of the out-of-plane stiffness for rigid 2-way diaphragms became an option.

It is important that all walls fit on the podium slab. If any wall extends outside the podium slab edge, unintended foundation supports can be added in the model. The reaction at the foundation support would not be transferred to the podium slab. This problem most often occurs at walls that are skewed to the global x or y axes and the slab edge segment is modeled continuous past the wall end. To prevent this from occurring it is best to snap slab edge segments directly to walls ends near the slab boundary. Displaying reactions in RAM Frame (Process – Results – Reactions) is a good way to check for unintended foundation supports. See reaction points circled in the screenshot below for an example of an unintended foundation support.

In RAM Frame, pseudo-flexible or semirigid diaphragms are the best options for models at wood framed levels. If walls are skewed relative to the global x and y axes in plan, then semirigid diaphragms should be used. See the following web pages for more discussion on these diaphragm types.

RAM SS Pseudo-Flexible Diaphragms

RAM SS Semirigid Diaphragms

In RAM Frame, the in-plane flexural stiffness of lateral walls above the podium level is always considered. As a result, the walls will be meshed with the podium slab and act as a stiffening element. This can produce significant moments at the base of the transfer walls. In most cases, loads are assumed to transfer directly from the wall to the slab, ignoring the wall stiffness above.

In RAM Concrete, there is an option to ignore the stiffness of walls above the slab. This option is located in the Analysis Criteria dialog in RAM Concrete – Concrete Analysis mode (Criteria –Analysis). Check the box for “Ignore Wall Stiffness on Above Story” to ignore the stiffness of the walls above.

More discussion on walls in RAM Structural System can be found on the following web page;

RAM SS Wall FAQs

In RAM Concrete, skip live load cases can significantly increase analysis time. Many models with podium slabs containlevels with many “other” type beam members. If the “Skip-Load the Live Load on Non-Beam Line Beams” is checked in RAM Concrete Analysis – Analysis – Criteria, the program will skip the live load on all of the “other” beams. Typically, this is not intended and the box can be unchecked.

RAM Concept Tips

RAM Concept offers three options for import of gravity forces: forces from RAM Steel, forces from RAM Concrete, and forces from RAM Frame. Generally, it will be best to use the RAM Steel forces as the first preference when importing. In RAM Steel, load is distributed to members based on a simple tributary area. The wall stiffness is considered in both RAM Concrete and RAM Frame. The transfer wall moments may be significantly higher if RAM Concrete or RAM Frame forces are selected with a higher priority than the RAM Steel forces.

When importing gravity forces from RAM Steel, line and point loads are converted to an equivalent load at the base of the wall assuming the wall is a rigid element. Point loads that are eccentric to the center of the wall will translate to moments and a non-uniform load at the base of the wall. Segmentation of the wall will affect the transfer wall load that is imported into RAM Concept. See example below:

Each wall is 20 ft long. The wall on the left is modeled with one wall segment. The wall on the right is modeled with two wall segments; there is a 1-ft segment near the end of the wall. Each wallhas a 10 k/ft live load and a 10 k point load located 1-ft at the wall end (same point where the right wall is segmented).

The following line loads are imported into Concept:

The line load on the left has a magnitude of 11.8 k/ft at one end and 9.15 k/ft on the other. These loads are calculated from:

10 k/ft + (10 k)/(20 ft)  +/- (10 k)*[(20 ft/2) - 1 ft)]/[(20 ft)^2*6]  = 11.85 k/ft and 9.15 k/ft

The line load on the right is divided into two segments, representing the 1-ft wall segment and the 19-ft walls segment.

The 1-ft wall segment has a magnitude of -0.008333 k/ft on one end and 29.99 /ft on the other. These are calculated from:

10 k/ft + (10 k/2)/(1 ft)  +/- (10 k/2)*[(1 ft/2)]/[(1 ft)^2*6]  = 30 k/ft and 0 k/ft

The 19-ft wall segment has a magnitude of 11.05 k/ft on one end and 9.473 k/ft on the other end. These loads are calculated from:

10 k/ft + (10 k/2)/(19 ft)  +/- (10 k/2)*[(19 ft/2)]/[(19 ft)^2*6]  = 11.05 k/ft and 9.473 k/ft

In this example, modeling the wall in one segment will result in more accurate loads in RAM Concept.

For elevated slabs, live loads are always imported as unreduced live loads. If you would like to account for live load reduction you can either reduce the loads manually after importing or manually assign live load reduction parameters in the Live Load Reduction tab of the Span Segment Properties dialog. See below:

For mat foundations, reducible live loads are reduced when they are imported into RAM Concept. If you are using a two-stage analysis, set the Code for Live Load Reduction to “None” after importing to ensure the loads are not reduced twice.

See Also

RAM SS Two-Way Decks

RAM SS Pseudo-Flexible Diaphragms

RAM SS Semirigid Diaphragms

RAM Frame - Wind Loads FAQ

RAM SS Wall FAQs

Structural Product TechNotes And FAQs

Following are the design codes supported by STAAD.Pro SS5. Users need to have suitable licenses as stated below in order to use these design codes.


STAAD US Standard Design Code License pack comprises the licenses of following design codes:


American Steel Design per AISC 360
Unified Specification - Steel member design per ANSI/AISC 360-05 and 360-10,
Since the ASD and the LRFD method are both addressed in those specifications,
they are referred to as UNIFIED.

Steel Design per AISC 
9th Edition ASD and 3rd edition LRFD

Design per American Cold Formed Steel Code – AISI 1996

American Concrete Design ACI 318 - Four versions of the
code are currently implemented: the 1999, 2002, 2005, and 2008 editions

American Timber Design- AITC 1984 and AITC 1994.


STAAD US Special Design code pack license pack comprises the licenses of following design codes.



Steel Design per AASHTO Specifications ASD and LRFD

American Aluminum Code based on ASD 1994 Sixth Edition (October, 1994).

American Transmission Tower Design Code Steel Design per ASCE 10 -97

Steel Design per American Petroleum Institute Code - based on the API 2A-WSD
standard, 21st Edition.


ANSI/AISC N690-1994 Code – needs the STAAD Nuclear Design Codes
SELECT Code Pack.

ANSI/AISC N690-1984 Code

ASME NF 3000 - 1974 & 1977 Codes

ASME NF 3000 - 1989 Code

ASME NF 3000 - 1998 Code

ASME NF 3000 - 2001 & 2004 Codes requires Nuclear Design Codes
SELECT Code Pack


STAAD Asia Design SELECT Code Pack comprises the licenses of following design codes:


Chinese Steel Design – GB 50017

Chinese Concrete

Singapore Concrete – CP65


STAAD UK Super Code license pack supports the UK codes (typically BS5950, BS8110, BS5400) and Euro codes as below with all National Annexes.


British:

BS 5950-1:2000 (steel)

BS 5950– 5:1998 (cold formed steel)

BS 8110-1:1997 (concrete)

BS 5400- 3:1982 (steel, concrete and composite bridges with amendment # 4051
and 6488)

BS 8700- 1997 (concrete structures for retaining aqueous liquids)


Euro:

EC2 ENV 1992-1-1:1991 (concrete)

EC3 DD ENV 1993-11:1992 (steel)

EC3 DD ENV 1993-11:2005 (steel)

EC5 Timber Design Per EC 5: Part 1-1




The STAAD ECC Super Code license pack supports all European codes that were previously covered by the STAAD packs Eurozone (typically French, Spanish and
German codes), North Eurozone (typically Norwegian and Finnish codes), and East Eurozone (typically Russian codes) as stated below with all National Annexes.



Euro:

EC2 ENV 1992-1-1:1991 (concrete)

EC3 DD ENV 1993-11:1992 (steel)

EC3 DD ENV 1993-11:2005 (steel)

EC5 Timber Design Per EC 5: Part 1-1




Russian:

SNiP 2.03.01-84 (concrete)

SP 52-101-2003 (concrete)

SNiP 2.23-81 (1999) (steel)

SP 16.13330.2011 (steel)


German:

DIN 1045-1:2001 (concrete)

DIN 18800: 1 & 2 (steel)


France:

B.A.E.L- 1991 (concrete)

CM66 1977 (steel)


Norway:

NS 3472/NDP (steel)

NORSK N-004 (steel)

NS3473 (concrete)

Finnish:

B4 (concrete)

B7 (steel)

Spanish:

NBE –MV103-1992 (steel)

EHE (concrete)

Swedish:

BSK 99 (steel)

BBK 94 (concrete)

Dutch:

NEN 6770 (steel)

Danish:

DS412 (steel).

Cyprus:

Cypriot Codes - Concrete Design in Cyprus


STAAD CAN/AUS/SA design code pack includes the Licenses of following design code:


Canadian Codes - Concrete Design per CSA Standard A23.3-94

Steel Design per CSA Standard CAN/CSA-S16-01

Design Per Canadian Cold Formed Steel Code S136-94

Wood Design Per CSA Standard CAN/CSA-086-01

Steel Design per CSA Standard CAN/CSA-S16-09

Australian Codes - Concrete Design per AS 3600 – 2001

Steel Design per AS 4100 – 1998

South African Codes - Concrete Design per SABS-0100-1



STAAD Indian Design Code pack includes the licenses of Following design codes:


Indian Codes - Concrete Design per IS 456

Concrete Design per IS 13920

Steel Design per IS 800 – 1984

Steel Design per IS 800 – 2007

Steel Design per IS 802 – 1995

Design per Indian Cold Formed Steel Code 801 – 1975


STAAD Japanese Design Code pack includes the licenses of Following design codes:


Japanese Codes - Concrete Design Per 1991 AIJ

Steel Design Per 2005 AIJ

Steel Design Per 2002 AIJ


STAAD Middle east Design Code pack includes the licenses of following design codes:


Egyptian 205 – Code of Practice for Steel Construction

TS 500 – Turkish Concrete Design Code


STAAD Latin American Design Code Pack comprises the licenses of following Design Codes:


Mexican Codes - Concrete Design Per MEX NTC 1987

Steel Design Per NTC 1987

Problem: Error "Nullable object must have a value" during design

During the AISC 360-10 Steel design process using release 13.03.00.99 (or 13.03.00.101) an error message can occur indicating:

The error stops the design process.

Solution

Use version 13.04.00.177 or later, otherwise use the 2005 edition of the code.

Using other section types can also solve the problem, depending what shapes are needed.

Problem Description :
When the user launches STAAD.Pro, the startup page comes up. User clicks on Open Project and browses to a .std file and as soon as he clicks on Open, the software crashes.

Solution :
User had to reformat the hard drive and reinstall all software from scratch and it took care of the porblem.

Note : This issue has only been observed in a particualr user machine running STAAD.Pro  version 20.07.08.20 and Windows 7 Enterprise Service Pack1. This is a very rare occurence and in case anyone runs into such issues, the steps listed in the following wiki should be tried out first ( specially if the crash is observed for a specific model )

https://communities.bentley.com/products/structural/structural_analysis___design/w/structural_analysis_and_design__wiki/23948.unable-to-open-staad-pro-model

Why do I get a warning about mass that's not associated with any diaphragm?

When you have line loads or any members with self weight masses considered (Under Ram Manager Criteria - Self-Weight) that occur outside of the boundary of the diaphragm slab edge you will get the following type of warning:

--------------------------------------------------
Some mass has been detected on one or more stories that is not associated with any diaphragms.
It will be ignored in Analysis unless it is combined with one or more diaphragms.
See the Loads - Masses command.

--------------------------------------------------

Under Loads - Masses you can evaluate the total diaphragm masses and you can combine these values with some diaphragm, override with User Specified Values or choose to ignore them by doing nothing.

One fairly common modeling mistake is to copy the line loads from another level type, but then modify the framing and slab edge without removing line loads that then fall out in space.

A similar error message also occurs when the Gravity load totals used for Notional loads are uncombined. See [[RAM SS Notional Loads]] for details.

Does the program automatically include storage or snow live loads in the masses?

No, the program calculated masses are derived form the user input Mass Dead Load only (and self-weight settings). Any portion of live, storage, partition or snow loads that needs to contribute to the total mass should be manually added into the Mass DL component of the loads, or the Loads - Masses can be overridden in Ram Frame. Refer to RAM Frame - Seismic Loads [FAQ] for more on the relationship of masses and seismic loads. Refer to [[RAMSS Gravity Loads FAQ]] for details on self-weight masses.

See Also

RAM Frame - Seismic Loads [FAQ]

[[Red Status Lights for Lateral Load Cases in RAM Frame]]

[[RAMSS Gravity Loads FAQ]]

[[RAM SS Notional Loads]]

Can I do a Pdelta analysis using STAAD for Response Spectrum load cases?

 A response spectrum analysis by definition provides the user with joint displacements which are the absolute maximum displacements which can occur at the joint when the structure is subjected to dynamic loads represented by the spectrum. This also means that these displacements do not necessarily occur at all joints at the same instant of time. In other words, the absolute maximum at joint 1 and that at joint 2 are most probably occurring at different instances of time. Another fact to be considered is that the response of the individual modes is combined using either the SRSS or the CQC methods depending on the input provided by the user. Both of these are approximate methods. The result is that the joint displacements, and consequently the member forces, cannot be used as a basis for obtaining the secondary forces on the structure. Hence, doing a P-Delta Analysis under such conditions does not make any sense.

I have a plate model. I am trying to generate wind loading on it using the automatic wind load generator but the load is not being generated. Can you please tell me why ?

The reason the automatic wind load generation is not working is because STAAD.Pro can only generate wind loading on beam members and when these members form closed panels. Since your model consist of plates, the software is not able to generate the wind loads automatically. Here are 3 options that you may consider. You may use any ONE that is most convenient for you

1. You may apply the loads directly to the plates using plate pressure loads

2. You may apply the loads to the nodes of the tank using nodal loads

3. You may create dummy beam members connecting the nodes of the plate mesh and that way the software would still be able to generate the wind loading at the various node points. The dummy members should be assigned a material of zero density and very low E value so that these do not add any loads or stiffness to the analysis.

Problem Description

When launching RAM Steel Column, RAM Concrete, RAM Frame, or the 3D Viewer, a RAM Container Failed to Create Empty Document error displays and the program crashes.

Solution

The problem has occurred on machines which use switchable graphics: a dedicated NVIDIA or AMD/ATI graphics card and an Intel Graphics chip (Intel HD Graphics 4600, for example). The following have been used to work around the problem for various users:

1. Updating drivers for each adapter.
2. Use the AMD Control Panel to use "Performance" mode for RAM Structural System.
3. Disable the Intel adapter through Windows Device Manager.

Problem Description

Warning message saying 'Warning, Design code license is not activated. Please activate the license in order to use the code' when trying to add a design parameter or design command for many other codes like ACI, AITC, EN 1993-1-1:2005, Aluminum etc.

Steps to Reproduce

1. Go to Design page inside Modeling Mode.
2. Select Steel and choose EN 1993-1-1:2005 as Current Code
3. Click on Define Parameters
4. Select any parameter and click on Add

The same issue has been observed for some other country codes as well.

Workaround

While adding the first design parameter, select the last defined command from the tree structure. Click on the Define Parameters or Commands button as appropriate and check the box 'After Current' before clicking on the Add button. The design parameter/command can then be added. Subsequently all other design parameters or design commands can be added as usual without any errors.

In case you still get the same error message, please open up the input command file ( can be accessed from the top menu Edit > Edit Input Command File ) and add a couple of design related commands that you would normally define to start the design for concrete/steel. Once you are done, save and close the editor. Subsequently you would be able to add as many design parameters you need to using the graphic user interface and carry out the design. A couple of samples, one for concrete and another one for steel, are shown below for reference. The commands in bold are the ones added using the editor

Sample command for concrete design as per ACI code

...
PDELTA 20 ANALYSIS
START CONCRETE DESIGN
CODE ACI
...

Sample command for steel design as per AISC 360-10 code
...
PDELTA 20 ANALYSIS
PARAMETER 1
CODE AISC UNIFIED 2010
...

Solution

Will be addressed in the STAAD.Pro Connect Edition expected in early 2017

See Also

Mesh Input layer

Why is it necessary to have priorities?

Without the priority system the modeling of floors would require one of two methods:

•  Objects for slabs of different thicknesses, beams, openings etc. could not overlap - this would be very tiresome for all but very simple floors, or
•  Depths would have to be additive. For example, you would have to deduct slab depth from beam depth. If you had to change the slab depth then a change would be required for the beam, unless its depth changed by the same amount.

Can I copy columns or walls below to the same above?

Yes.

1. Select all of the columns or walls you wish to copy.
2. Choose Edit > Copy (or right-click and choose Copy from the popup menu that appears). Then double click off the edge to select nothing.
3. Choose Edit > Paste (or right-click and choose Paste from the popup menu that appears). The pasted objects are the current selection.
4. Choose Edit > Selection Properties, or right-click and choose Selection Properties.
5. Change Support Set from Below to Above, and click OK.

Note: It is important that you do not abandon the process after pasting. Otherwise, you will have two supports below at various locations, which causes calculation errors.

Element layer

How can I view the slab without the mesh?

Choose Layers > Element > Slab Summary Plan or go to the visible objects dialog box and check the "Outline only" option under slab elements.

What is the difference between beam and slab elements?

There is no difference unless you modify their behavior. See discussion of behavior in “Slab area properties” on page 56 and “Beam properties” on page 57. The difference in only in the modeling, a beam always has two parallel edges offset from the two end points, while a slab area polygon can be any shape in plan.

How many nodes or elements are allowed?

There is no limit, other than the limitations of your computer. If you find the program performance too slow, consider any of the following to help:

1. increase the mesh size to reduce the number of elements 
2. delete an imported drawing file that is no longer needed 
3. reduce the number of load cases and/or load combinations
4. reduce the number of design strips or increase the spacing of the design strip cross sections.

How many elements should I use per span or panel?

This cannot be answered directly as it depends upon the structure and loads. The maximum is 32.8 feet (10 meters). To speed the analysis, it is useful to choose a coarse mesh for preliminary design and a fine mesh for final design.

• A coarse mesh might have an element size of span length /6.
• A fine mesh might have an element size of span length /12.

If in doubt, you should investigate the effects of different mesh element sizes.

Columns

Do columns restrain the slab?

Depending upon the defined fixity, columns can provide rotational and lateral restraint. If the far end of a column is defined as a “roller” support (or both ends of the column are pinned) then the column does not provide any lateral restraint to the slab. Columns above the slab do not support the slab vertically, they can only restrain the slab rotationally and laterally.

Why is there deflection at the face of a supporting column or wall?

Columns in Ram Concept connect to the slab finite element mesh at a single node located at the column centroid. They are not solid objects nor do they provide vertical support to multiple nodes. This is apparent viewing the Elements - Standard Plan.

As such, deflections in the slab start from that node and increase towards the face of the column. For small columns this may not matter much, but for large area columns this is significant. 

To mimic the behavior of a stiff column support, we suggest modeling a thick and stiff slab object that overlays the column volume like a mini-drop cap. Be sure to assign a higher priority to this patch of concrete. It is recommended to model this patch with an elevated top of concrete elevation such that the slab centroid aligns with the mid-depth of the patch in order to avoid eccentricity at this joint.

The same approach could be taken for thick walls supporting the slab as well. A beam or slab object can be used there.

Beams

Where should you define the end points of a beam, at the face of the column, passing the column or at the center line? 

The general preference is to model the beams through the column, extended to the slab edge since it best matches the built condition and how things are formed. Stopping the beam at the column centerline results in a slightly more flexible system.

Walls

Do walls restrain the slab laterally?

Yes, if you select Shear Wall as a property. If the Shear Wall is unchecked then the slab is allowed to slip freely over the top of the wall. The walls rotational stiffness is independent of the Shear Wall setting; use the fixity settings to control the walls rotational stiffness about its longitudinal axis.

What is the effect of specifying walls above?

Wall elements can be used to model the stiffness and spanning ability of walls connected to the slab. Walls above behave similarly to beams in that they stiffen the floor. One could actually model the walls above the slab as beams instead, but it is not generally recommended.

Using beam or slab elements does have some advantages over using wall elements (“wall-beams”):

• Concept design strip cross sections automatically integrate the forces across slab-beam elements; wall-beam elements are ignored in these integrations, however.
• Also, Concept provides you many controls over how slab element results can be displayed; wall-beam elements (like wall elements) can only plot their reactions to the slab.
• However, Concept’s standard slab elements have a torsional stiffness that is proportional to their depth cubed. This can cause a large over-estimation of the torsional stiffness for a very thick slab element if it is adjacent to relatively thin elements. “Wall-beam” elements do not have this problem. As such, walls above that are modeled as upturned beams should use the “No-torsion” beam property.

When modeling wall-beams above the slab, Concept interprets some of the wall element parameters differently than for walls below.

• If the wall-beam is not rotationally fixed to the slab then the wall-beam will have zero torsional stiffness.
• If the wall-beam is not a shear wall then it will have zero axial stiffness. The vertically compressible and rotationally fixed at far end parameters are ignored.

Wall-beam elements have one advantage over slab elements.

• Slab elements of drastically differing thicknesses in the same structure can cause the automatic plotting controls to show (correctly) huge force variations in and adjacent to thick slab elements and almost no variation within the thin slab element areas. This does not generally happen if walls above are modeled as wall-beams.

Do walls above the slab provide rotational restraint?

There is no restraint at the far end of a wall above. (Even if “Rotationally Fixed at Far End” is checked, it is ignored).

Mats (rafts)

Does Concept ignore soil tension?

You can reduce the tension by iteration. The tension gets closer to zero with an increase in the number of iterations. See “Zero tension iteration options” on page 126 for more information.

What value should I use for the area springs Z force constant?

The geotechnical engineer commonly provides a value called the “subgrade modulus” or “modulus of subgrade reaction”. As a guide only, realistic values vary from 100 pci (approx. 25 MN/m3) for soft clay to 750 pci (approx. 200 MN/m3) for very dense gravel.

RAM Concept automatically multiples the area spring constant (units of force per cubic length) by the tributary area of each finite node (determined from mesh size) to determine the spring constant (units of force per length) at each node.

The subgrade modulus is determined in the field using a plate load test, typically using a 1ft x 1ft square plate. The actual modulus value is dependent on the size of the loading area: for a given displacement, the modulus value decreases as the plate size is increased. RAM Concept does not automatically adjust the input area spring constant to account for this size effect. If you are not sure what area spring constant to use, consult with a geotechnical engineer. Some engineers choose to run the analysis with a spring constant varying from 0.5 to 5-10 times the provided value and design for the worst case (see ACI 336.2R-88). In many cases, the stiffness of the mat is much larger than the soil stiffness. In these cases, the forces in the slab and the computed soil pressure may not be sensitive to the area spring constant.

Note: Area springs are always assumed to be compression only springs in the Z direction, but they behave elastically in the R and S axes. Line and point springs are also linear elastic supports resisting tension or compression.

If 2 or more area springs overlap, is the spring stiffness cumulative?

Yes, soil area spring stiffness values are cumulative. If you model two area springs with 100 pci stiffness you will get 200 pci stiffness in the intersection.

Does Concept design for soil heave?

Not directly. You could draw spring supports that approximate varying soil support.

Do I need to draw the columns above in a mat foundation model?

No, but it is a good idea. It ensures a node is placed at that location where there is likely to be a heavy point load. The columns also provide convenient snap points for tendons or design strips.

Can Concept design for pile supports?

Yes. Use either (flexible) columns under, or point springs. Skin friction is not considered.

Can Concept design for pile and mat (raft) action together?

Yes, but the results could be very susceptible to variations in geotechnical parameters. For example, if the soil’s stiffness is overestimated, the actual pile reactions could be significantly underestimated. Use caution.

Does the area spring support have to match the mesh?

No. An oversized area spring is fine. The program applies the individual nodal springs based on the mesh tributary area.

Can the soil stiffness vary?

Yes. You can vary the stiffness in two directions. See “Area spring properties” on page 55.

Where do I select the allowable soil bearing pressure?

This is not an input parameter. You need to look at soil bearing pressure plans (which have a maxima / minima legend) to assess the maximum pressures. 

What is the Structural Dashboard V8i?

Click Here to view the Dashboard and Structural Synchronizer Launch Video		Download Structural Dashboard from Fulfillment Center
The Dashboard is a free tool that assists in managing the data and workflow of projects from start to finish.	The Dashboard provides a Web Portal and Launch Pad to learn how Bentley's comprehensive products integrate in more efficient project workflows.

Structural Dashboard V8i

Benefits of the Structural Dashboard

The Structural Dashboard is a free tool that assists in managing the data and workflow of projects from start to finish. The Structural Dashboard provides a single interface to utilize Bentley's integrated products for a complete project workflow.

• Manage workflows for common project type (including building workflows and plant workflows)
• Use a unified interface to launch all your Structural applications
• Create customized workflows specific to your projects
• Receive Structural News from customizable RSS feeds
• Join Structural online community and access blogs, wikis and forums
• Download product upgrades from Bentley's SELECTservices Center
• Manage project files and links within your workflow
• Consolidate common project information and dynamic links to project documents

Integrating Structural Workflows

The ability to integrate structural project workflows - including modeling, analysis, design, documentation and detailing - enables structural engineers, detailers and fabricators to dramatically increase project efficiency, reduce errors, and improve quality control.

Bentley's integrated structural modeling works behind the scenes to provide engineers with a shared and dynamic repository for all structural content including visualization and revision history for increased coordination.

Rollover the links below to see integration descriptions and click the links watch integration videos :

Building Workflow Examples

RAM Structural System and RAM Concept RAM Connection and RAM Elements RAM Structural System and Structural Modeler RAM Structural System and RAM Concrete RAM Structural System and RAM Connection RAM Structural System and RAM Elements RAM Structural System and RAM Foundation RAM Structural System and RAM Steel RAM Structural System and RAM Frame RAM Elements and RAM Concept ProStructures and RAM Structural System ProStructures, RAM Elements and RAM Connection ProStructures and RAM Connection

Plant Workflow Examples

AutoPIPE and AutoPLANT ProStructures and STAAD.pro STAAD.pro and AutoPIPE STAAD.pro and STAAD.foundation ProStructures, STAAD.pro and RAM Connection STAAD.pro and Advanced Analysis Module

More info...

To learn more and connect with others interested in this topic please visit:

• Integrated Structural Modeling Community

Problem:

I have installed STAAD.Pro in my machine; when I try to launch it from Structural Dashboard it fails to run.

Solution:

To update the link of STAAD.Pro from Structural Dashboard please follow the steps as mentioned below.

Rename  BentleyProducts.xml file from

C:\Program Files (x86)\Bentley\Engineering\Bentley Dashboard V8i SELECTseries 2\BentleyProducts.xml

to  BentleyProducts.xml.original.  To achieve this, right-click on the file and select the option 'Raname'; you might get a warning saying the file will become unusable, click on yes.

Copy the attached BentleyProducts.xml file in

C:\Program Files (x86)\Bentley\Engineering\Bentley Dashboard V8i SELECTseries 2\

(Please visit the site to view this file)

There are situations when a partial diaphragms are required to be modeled. This caters to the situation when a diaphragm extends over only a portion of a floor. In addition, you may have to consider a situation when a floor is composed of a rigid portion (like- thick slab) and some openings or a relatively much flexible portion (like- corrugated steel decking). There may be situations when a high-rise have multiple towers where the floors are situated at the same Y-level. Such conditions demand multiple diaphragm definition at the same Y level of floors.

You need to select the nodes where the Rigid Diaphragm condition exists and assign the Floor Diaphragm to those nodes. You can have a master node created at the location of center of mass calculated by the program or defined by yourself.

If you have a situation where you have a rigid floor portion and relatively flexible portion, you can slightly move the nodes of the rigid portion in upward direction considering the tolerance set in the program. You can define a rigid diaphragm at the location of the nodes. The other joints which is the flexible portion of the floor would not be included in the newly formed diaphragm as they will be at the different Y level.

Procedure

• In STAAD.Pro we can define multiple floor diaphragms laying at same Y level in a single model. You have a model like the following

• Go to General page and move to Specification subpage. Choose Tab >> Node >> Floor Diaphragm >> Enter Height in Floor Level >> Select Nodes >> Add. Please refer to the following pictures:

• Add another Rigid Diaphragm for the same floor level and assign the specification to the next set of nodes.

• A sample model has been attached. (Please visit the site to view this file)
• You can see the following information regarding the diaphragm in the output file:

Following are the known issues discovered in version 08.00.01.33