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[satish_jain]

Dear Participants,

A lot of literature and international code provisions are available on ductile detailing of steel structures.

Why is it then you don't see ductile detailing in most high rise steel structures that are coming up in cities like Mumbai? I bring this up as the Indian codes specifically talk about ductile detailing in moderate and high seismic zones like Zone III, IV, V and that it is recommended/required in RCC high rise structures in Mumbai. Why is the requirement "relaxed" for steel structures by lack of any statement for provision of the same.

How is a high seismic zone such as New Delhi and suburbs faring in ductile detailed steel structures?

I invite comments and my co - Sefian's views on the above.

Thanks,
Satish Jain

[Yogesh.Pisal]

Dear Sir,

I think BIS has overcome this problem after incorporation of IS800:2007.

Chapter 12 in the code is fully dedicated to the ductility provisions for all the steel buildings. Further, it is important to note that as per Cl 12.1, IS 800: 2007 these provisions are applicable for all structures in all seismic zones.

These days there is lot of criticism in the industry after seeing the over size of connections and further this has increased after knowing the fact that there will not be any cost reduction (depends on case to case).

But, I think this very important and most required move by the BIS.

Thanks & Regards,
Yogesh Pisal

[alpa_sheth]

[str.engr]

Good question Satish.�

For the longest time we blamed nonavailability of appropriate sections to adequately design ductile steel structures. Given the poor stiffness we seem to be able to achieve even in concrete buildings (I am going �by the high Time periods I see quoted for designed buildings) I worry about the lack of stiffness in our tall steel buildings coupled with inadequate ductile detailing.�


我不认为我们有我们的延性requ“放松”irements as much as we perhaps do not know to what level of ductility we should design our buildings for. Our codes are pretty silent on this. We do not have an equivalent of IS 13920 (conc ductility code) for steel. I am concerned about the way IS 800 approaches ductility issues. For one thing, IS 800 has always been perceived as a steel code for industrial design and does not adequately address the requirements for a high rise building (commercial/residential) in steel. I also have problems with a common level of ductility for all buildings regardless of the seismicity of the region. I remember for IS 13920 we tried to add an Intermediate Ductile Moment resisting frame system" for moderate ductility regions but it did not go beyond the draft code - at least as yet.�


�Ductility requirements need to account for a) the structural system in which the member occurs (a column in a tube frame will for e.g. have different ductility & design �requirements than a column in a frame -shear wall building, b) the member behavior (shear/bending/axial etc.), c) seismic design grade to which the member should be designed for (which would in turn depend on the seismicity of the region, criticality of the member and the building, sting of the building, building height etc.�


I feel that a prescriptive approach addressing all these issues (and more) will be better suited for us presently. I think some international codes do exist which address high rise buildings in steel in such a manner.�


regards,
Alpa �

On Sat, Dec 1, 2012 at 2:13 PM, satish_jain forum@半岛软件下载www.buonovino.com)> wrote: