Automatic effective length calculation

-->Summary of effective length factors for steel & RCC columns as per Indian codes as below:--> 1: Annexure-D , clause: 7.2.2 of IS 800-2007 (Ky & Kz of steel columns) 2: clause 8.3 (Table-15) of IS 800-2007 (Kx). 3: Annexure D-2.1 & D-3 of IS 800-2007 (Ky & Kz for stepped columns) 4: Annexure-E , clause 25.2 of IS 456-2000 (Ky & Kz of RCC columns). -->Refer following snaps, all of above requirements should be implemented as mentioned in a single revision like other softwares, so that deliverables of staad pro software can be enhanced.

The feature of automatic effective length factor ky and Kz has implemented, but effective length factor for lateral torsional buckling (Kx) or LLT has not been implemented till now, it strongly needs to implement as per clause 8.3 and table 15 of IS 800 2007 code.

Is automatic effective length factor in staad for RCC and steel structure for an Indian code IS 456 2000 and IS800 2007 implemented ??

If the suggestion is for another code, then that is another idea, The original solution has been completed.

It's okay that, staad pro 2023-2 version has been release with effective length and effective lengths factors as per AISC code, but the same should facilitates as per Indian code IS : 800-2007 (annexure-D)and IS 456:2000(Annexure- E).

Please note that STAAD.Pro 2023-2 has been shipped with a tool to determine the unbraced lengths and effective length factors according to the AISC 360 code.

Staad pro takes node to node distance for member design as Ly and Lz , irrespective of inspecting whether member break in any of its direction or not, this member length value true for one of the axis but may be incorrect for other direction,this problem need to resolved in staad.

Automatic Effective length/ effective length factor of RCC/steel column should be incorporated as below . 1- For RCC structure, Annexure- E of Code IS:456 2000, 2- For steel structure, Annexure-D of code IS:800 2007 & Annexure D-1 and D-2 of IS 800:2007

Effective length factor Ky and Kz should also be incorporated for "single stepped" or "double stepped" columns, as per Indian code IS: 800 2007 annexure : D-2 & D-3.

Dear All,

With reference to the above constraint in calculating the KZ parameter for Moment Resisting Frames, a Macro has been developed.

This macro is aimed at..

1. Minimum manual inputs to Macro, which shall minimized the calculation checking efforts of engineer.

2. User is only responsible for correct modelling of staad file. Thus the checking efforts are limited to staad input file. Minimal efforts are then required to verify that the correct inputs are entered on to the Macro screen.

3. User shall initiate a design of Moment resisting sway frame by assuming KZ parameters (May be by approximating the end conditions with the standard diagrams given in code).

4. Once the preliminary section sizes are determined the exact KZ parameters can be entered which the Macro calculates in automated way.

5. The Lengths and Section properties are taken from Staad file itself and no manual efforts are required.

Since all (Most of the inputs) the required inputs are obtained from Staad file itself, a similar approach can be adopted in staad engine and this way the user intervention can be completely eliminated to achieve both accuracy and Saving of time and efforts.

Users, please note that the attached macro is prepared considering the requirements/formulae as per Eurocode National Annex - Nederlands.

Similar Macro can be developed for other codes as well.

The detailed video for "how to use" the macro & flowchart can be viewed at below links

https://www.youtube.com/watch?v=QfMJcA2wiAA&t=12s

https://www.youtube.com/@CivilBotsforBeginners/featured

Regards,

Pravin Agashe.

Correct. Assigning design parameters is currently in the domain of the analytical workflow.

But currently this is not how it is set up, right? The physical modeler does everything but set up the design parameters. Which is still done in the Analytical modeler.

I just want to make sure that I am not missing some functionality within the physical modeler that could make my life easier.

The first step in this solution will be for the Physical Model to take ownership of setting design parameters. That means that similar to modelling and geometry functions, that becomes restricted in the analytical environment. Then we can build a system that can automate the parameters for various attributes such as effective length and deflection lengths.

Just for clarification, does the physical model tell the analytical model the Lx, Ly, and Lz values? Likewise, does it also tell it DJ1 and DJ2 values? My understanding of the modeling was that it doesn't do that. At least if I view the design commands in the analytical model (after converting from the physical model), it won't have those values defined.

I feel like the poster was asking for something like that.

Thank you for your post. I think the first part is really about accounting for the fact that you are looking to retain the concept of a physical beam or column even if it has to be sub-divided for analytical purposes. That is already addressed by defining your model in the physical workflow. If I understand correctly, your suggestion in the second and third points is about automatically calculating the effective length factors, we do have this in our backlog. The factors themselves being determined by the stiffness of the members that it is connected to in the two orthogonal axes.

In staad pro CE, in analytical modeler, when we add new node/s,the existing member is devided into segments, and the program takes length/effective length of that member as part, not takes as a whole member length about its major or minor axis accordingly, so my suggestion is that, 1-kindly add the features that program automatically take the length of member (beams and columns)as per its division on major or minor axis accordingly...... 2- like steel structure, the effective length of beams and columns should be automated in RCC structure 3-Also in steel structure design effective length factor Ky and Kz is to be provoided manually after confirming moment release or reatrained, translation is release or restrained, and also the major and minor axis, this manual efforts is so applied to each and every member and thqt is time consuming, error prone and tedious, so kindly add that feature.