Structural Instability & Zero Stiffness: Part 3 - Solving Instability problems || Modelling error

[@ArunKumar-ji6nr]

Dear Sir, You are superb in structure analysis and your way of teaching is very efficient. This video is very useful for a structural engineer.

[@sudhirpatel2382]

Thankyou sir for such detailed videos . Your all videos are having standard content and your way of explanation is also excellent

[@garvitkalla5230]

so so much thanks sir i have been worried about this problem and tried every thing no luck, but you explained it like a pro.

[@surojit_ghosh]

Glad it helped.

[@garvitkalla5230]

@@surojit_ghosh sir need some information if we do not release moments at the ends of beam,how much it will affect the design or is it necessary?

[@garvitkalla5230]

A request sir can you make a video on how to utilize members in R.c.c structures?

[@surojit_ghosh]

For steel structure, depending on the connection, we need to assign member release, for example, for shear connection, we can assign moment release at that end. For concrete structure, it depends on the designer. Several designers assign release to the secondary member though it is not 100% acceptable as monolithic construction and extension of reinforcement in primary member establish a moment connection.

[@sadanandaswamy6918]

Wanted to have a detailed video of Statics check and seismic analysis for a building with shear wall and plates for slabs.

[@prasadankam]

Hello Sir, First of all, I just want to thank you for your time in explaining the design concepts that goes into the staad software. The video series on instabilities and zero stiffness warnings is really informative and very insightful to a lot of engineers. Can you please do a video series on static seismic analysis with accurate time periods as you hinted in the video. I am sure a lof of engineers would want that. Also, this is probably not the place for this topic but can you also please do a series on analysis of PEB structures.

[@surojit_ghosh]

First of all, thanks for your feedback. I have some plans to start a new series on seismic analysis but due to time restraint, I am unable to work on this. Videos on modelling, analysis and design of PEB structure will be uploaded soon, stay tuned for further updates.

[@prasadankam]

@@surojit_ghosh Thank you sir for your response. I can understand your time constraints and everyone would be happy for any kind of information from your side. You said something about the design of a box culvert at the end of plate meshing video series and I think that would be a very informative series. One request though, please talk about the crack width checks and limiting stress in steel (130-150 Mpa), if it's a water retaining box culvert. It will be highly appreciated if you can do a series on the effective lengths to be considered in columns. A lot of structural engineers are ambiguous about this part especially when there are no beams connecting the columns at floor level. Effective lengths to be considered when sway, non-sway condition and how to do a proper second order analysis. I have heard that if we do a second order analysis on the structure, we don't have to worry about the effective lengths, your ideas and approach on this subject will be really helpful. Also, I have a couple of questions in physical modeling...... 1) Is there a way we can define truss specification in physical modeller? I have seen the options of hinge both ends and axial behaviour, but my concern is what if we want to do a partial release? Also in axial behaviour, we have the options of tension-only and compression-only ....... Does this mean we have to define tension and compression members seperately in a truss arrangement ? 2) in analytical modeller we have a lot of options for selection like node cursor, member cursor, geometry cursor, missing attributes, based on properties.....all these options are available in physical modeller as well ? I can't find them. 3) In the spreadsheet tab on the right, I don't see all the options like you guys have nodes, members, surface etc., I have only nodes table and I can't figure out to change the layout of this tab. I am sorry I have asked about a lot of information in a single comment, I have very recently started using the physical modeller and these are a few options I couldn't find. I know these are some very basic questions about modeling but your response will be highly appreciated. Thanks for your time. Regards Prasad.

[@josephlucas4115]

Hello may you please prepare a video on how to design different types of spiral stairs in Staad pro,and how to perform deflection check by vibration method and span depth ratio method using BS or IS standard

[@sadanandaswamy6918]

Very nice presentation sir. How to get the value of sub-grade modulus for different types of soil.

[@surojit_ghosh]

You can get the soil subgrade modulus value from soil test report. Either bearing capacity of soil or the subgrade modulus value is reported in the soli test report. You can easily convert bearing capacity to subgrade modulus value using (BC*safety factor/allowable settlement). Normal range of subgrade modulus value for different soil is - 4800 to 128000 kN/m2/m.

[@sadanandaswamy6918]

@@surojit_ghosh thank you sir.

[@josephlucas4115]

Excellent demonstration

[@viralvista5509]

Can you please make a video on static analysis

[@win-pe7ud]

thanks sir.

[@sudhirpatel2382]

Sir please make a video on how to reduce utility ratio of steel members. And how utility ratio is calculated in staadpro

[@surojit_ghosh]

I have already published several videos on these topics. To get an idea how we can optimize the overall steel usage in any structure, check the Steel Structure Optimization series -- kzbin.info/aero/PLxLi_mmlPeipFQH_YOTTeG9waqeX9CZKN To know the basics of steel design as per IS800:2007 code, check the Steel design series -- kzbin.info/aero/PLxLi_mmlPeirxD3gUWVF-7xSHqDhZ_ie_

[@balajipandi8663]

Very good Sir

[@ArunKumar-ji6nr]

While designing steel structures in staad pro sometimes, a failed member show very huge utilization ratio like 678 what's the reason behind that pls explain sir

[@surojit_ghosh]

You can include TRACK 2 command and check the detail result in the output file. One reason, some checks are not performed or the capacity is not calculated properly due to erroneous property values.

[@viralvista5509]

How can I use more accurate time period

[@surojit_ghosh]

We can auto-calculate the fundamental time period for any structure in STAAD and use that for static seismic analysis, this is more accurate approach and for any complex structure, like irregular base or structure on slope, this is the only solution.

[@viralvista5509]

@@surojit_ghosh how do we auto calculate fundamental time period sir

[@SANJAYPAPU]

I have analysed one B+G+7 storied building and it's showing error message " Eigen solution failed. This may be due to ill-conditioned stiffness matrix ", " Failed in Advanced solver Eigen ". Please do support to rectify this. Thanks in advance.

[@surojit_ghosh]

It seems like an instability issue. You can check for multiple structure/orphan nodes. If that does not solve the problem, you can upload the relevant model in Bentley Communities (communities.bentley.com/products/ram-staad/f/ram-staad-forum) for review.

[@SANJAYPAPU]

@@surojit_ghosh thanks dada, yes it's due to the multiple structure, overlap and orphan nodes related issue. Yesterday after making the making the comment I realized and solved it 😁.

[@rupeshkhandekar6340]

--------------------------- Error --------------------------- An unhandled exception occurred: Process with an Id of 21443 is not running. at System.Diagnostics.Process.GetProcessById(Int32 processId, String machineName) at System.Diagnostics.Process.GetProcessById(Int32 processId) at Bentley.Staad.Editor.Management.StaadEditorWindowManager.StartCallerProcessMonitor() at Bentley.Staad.Editor.Management.StaadEditorWindowManager.LoadMainWindow(StaadEditorAppManager appManager) at Bentley.Staad.Editor.Management.StaadEditorAppManager.LoadMainWindow() at Bentley.Staad.Editor.Management.StaadEditorAppManager.LoadApplication() at Bentley.Staad.Editor.StaadEditorApp.OnStartup(StartupEventArgs e) at System.Windows.Application.b__1_0(Object unused) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler) --------------------------- OK ---------------------------