Implementation of IS800:2007 code in STAAD - Part 2: Compression, Shear & Bending || LTB || Buckling

IS800:2007 is the Indian standard code of practice for design of steel members using limit state method. It is a large code and the most problematic area of this code is several sections and design clauses are not properly clarified. In this session, I have discussed on design for compression, shear and bending using IS800 code in STAAD.
I have discussed about compression member design using section 7 of IS800 code, discuss about the general design rules and also about the web slender section design. Design for Shear and Bending following section 8.4 and 8.2 is also covered along with bending capacity calculation for high shear case. Also I have discussed about general design principles and clarification of design results reported in the output file.
Chapters:
0:00 Introduction
2:07 Compression Member Design
14:24 Design for Shear
19:12 Design for Bending
34:26 Extract Design parameter information
36:18 Design Philosophy
39:36 Discussion on Output file design results
40:48 Design results in Post-processing mode
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[@sudhirpatel2382]

Very informative video

[@arijitdey13]

How is bending capacity of a web slender section calculated in staad as there is nothing guided in IS:800-2007?....can you please help us know?

[@surojit_ghosh]

Bending capacity depends on several factors, whether the member is laterally supported or not, whether the section is subjected to high shear, or if the web is susceptible to shear buckling before yielding. And obviously, combination of these conditions. Indian code is completely silent about these, how to calculate bending capacity for web slender section properly considering all these different conditions. If you check other international codes like AISC or EC3 code, they clarified each possible conditions but nothing is mentioned in IS800:2007 code (even you will not get any positive response from the code committee).
We have consulted few international design codes before implementing this in STAAD. It is not possible to post the details here as it requires several calculations and screenshots. If you can post this in Bentley Communities (communities.bentley.com/products/structural/structural_analysis___design/f/5932.aspx), we can provide you proper clarification with calculations.

[@alameen1870]

14:50 If we orient beam and column in a way that the beam is connected to web of the colomn.I would like to know how staad consider this.

[@surojit_ghosh]

Your question is not clear to me. Do you want to know about analysis forces, member design results or connection design?

[@nandkumarsharma4882]

very informative thanks

[@surojit_ghosh]

You're welcome. Check Part 1 and 3 also for full information about the implementation.

[@jainamshah1378]

Is there any criteria for ly and lz breaking length
For example if ISMB 200 beam is connected to main main beam of WH1000 in its web will it be considered that the length is breaked in y direction and the length of beam is full in its z direction??

[@jainamshah1378]

Because I have one problem in design of crane girder the web is slender and i couldn't find a way to check it for bending and lateral torsion buckling will it be consider that if the crane girder is connected with chequered plate with stich weld will it be considered as laterally support or unsupported beam
Kindly reply

[@surojit_ghosh]

What you are looking for is Lx(or Kx) parameter which is used for LTB & bending capacity. Ideally if the flange is supported at any intermediate distance against buckling, then you can consider the modified distance as Lx. But the lateral support must have adequate stiffness to resist the lateral buckling. Just for example, if there are two parallel beam and a tie rod is welded to the top flange, that is not a lateral support. Depending on your intermediate support condition and resistance, you need to find out the length for lateral torsional buckling.
By the way, for IS800:2007, there is only one parameter (unlike AISC, UNT UNB UNL UNR), so before defining the length, consider the bending profile of other flange and other side of the flange.

[@jainamshah1378]

@@surojit_ghosh OK Thank you, so much
one more query is there,
i have connected Crane girder with axuillary girder at the top flange with truss like configration with top flange at every 3m so i have consider Lx as 3m and with bottom flange lateral tie at every 3m and also i have given diaphram or surge plate at both the end of crane girder and also the top flange of crane girder is hold with cheq. plate with full welding. so in these case i have consider it as laterally support with Lx of 3 m
is it okay to consider that??? i need help

[@surojit_ghosh]

As mentioned, there are several factors which govern the lateral support specification, and it is not possible for me to understand the exact support condition from your statement. Just consider the structural condition of the member when subjected to LTB and if you think assigned lateral supports will restrict this buckling, then you can consider the modified LTB length as 3m.

[@jainamshah1378]

@@surojit_ghosh okay thank you for the info and in general in future if I need some help how may contact you ??

[@sadanandaswamy6918]

It would be helpful if there is a video on defining the design parameters for a peb or any steel structure using open staad or macro

[@surojit_ghosh]

Thanks for your suggestion Sadananda. I have plans to create some videos on design parameter assignment for PEB structure as well as how to assign design parameter using OpenSTAAD functions. I will try to post those videos within next few months.
You can get some ideas about PEB structure design in the third part of IS800 session posted here --
czcams.com/video/hqqMsi1LNp0/video.html

[@Enfld1122]

Thanks for arranging the session,As you say , effective length factor assigning to each and every member is very tedious task as it needs to calculate stiffeness of connected beams to the columns and many more, but this task can be done automatically by using vba/ open staad tool , kindly provide the vba/macro excel sheet for automatic effective length factor . Thanks..