Seismic Loadings 8

[Engr ZANIA]

Hi
Is there anyway to use ASCE's seismic coefficients (S1, Ss etc.) for countries/cities outside USA. If yes, please share

 

[r13]

Try this website, Link. Or this, Link

 

[Lomarandil]

Your first step should be the local seismic code, even if you need to convert a provided value (say PGA or a different return period) to ASCE S1 and Ss equivalent.

UFC 3-301-01 can be helpful in some cases.

For a first approximation, you can take PGA values from a source like GSHAP and convert approximately by S1=2.5*PGA, Ss=5.0*PGA

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just call me Lo.

 

[HTURKAK]

Yes ...your first step to look local seismic code as Mr Lomarandil pointed out.. If a response spectrum shape is prescribed in the regulatory requirements with 5% damping and 500 year return period, use it.

If there is no response spectra shape is prescribed and only you know the peak ground acceleration , you may construct the response spectrum shape S1=2.5*PGA, Ss=5.0*PGA ( as Mr Lomarandil pointed out and a pink star to him for this respond ) and modify for the local site soil conditions.

Other methods, site specific studies, based on Probabilistic Site-Specific MCE Ground Motion and Deterministic Site-Specific MCE Ground Motion..

If you define the country , may be you may get better responds..

 

[PROYECTOR]

For a first approximation, you can take PGA values from a source like GSHAP and convert approximately by S1=2.5*PGA, Ss=5.0*PGA

Hi Lomarandil, where do those values come from?

Some standards, like API 650, recommend using S1=1.25*PGA and Ss=2.5*PGA. In this case, PGA, as well as S1 and S2, correspond to a 2% probability of exceedance within 50 year period (maximum considered earthquake).

 

[Lomarandil]

For a first approximation, you can take PGA values from a source like GSHAP and convert approximately by S1=2.5*PGA, Ss=5.0*PGA

Hi Lomarandil, where do those values come from?

Some standards, like API 650, recommend using S1=1.25*PGA and Ss=2.5*PGA. In this case, PGA, as well as S1 and S2, correspond to a 2% probability of exceedance within 50 year period (maximum considered earthquake).

Yes, that is correct when the PGA is reported as 2% probability of exceedence in 50 years (2475 year return) which is the same as ASCE 7-10+.

Many PGAs are reported as 10% probability of exceedence in 50 years (475 year return). In this case an additional conversion factor is needed, approximately 2.0 for many cases (per Lubkowski, 2010).

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just call me Lo.

 

[PROYECTOR]

Lomarandil, thanks for the clarification!