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ASCE 7-1995 Seismic Load: factored or not?

ASCE 7-1995 Seismic Load: factored or not?

(OP)
An equipment vendor has given me data for sismic design of the equipment foundation based on “ASCE 7-95”, but I don't have this publication; can someone to tell me if the seismic forces under ASCE 7-95 are factored or not?

In case they are factored, according to UBC-97 (§1612.3.1) it must be divided by 1.4 in order to use it in ASD load combinations with Dead and Live loads. I think ASCE 7-95, in the year 1995, provides the seismic load already factored, but I an not sure.

Can anyone please help me?

RE: ASCE 7-1995 Seismic Load: factored or not?

Both the LRFD and the ASD load combinations in the 7-95 have 1.0E.

I started reading the commentary on it but couldn't spend enough time to get into it.  I believe its an ultimate E value with some sort of adjustment required on the allowable stresses for ASD but I'm not sure (the commentary has some sort of α value applied.



RE: ASCE 7-1995 Seismic Load: factored or not?

(OP)
Thank you JAE for your prompt answer, but in reading your comments something is not clear.

I have the ASCE 7-05, (the latest version) which in its paragraph §2.3 “Combining factored loads using strength design” (LRFD) writes:
Load Combination 5. reads 1.2D +1.0E
Load combination 7 reads  0.9D + 1.0E
Note that E is not factored.

And in paragraph §2.4 “combining nominal loads using allowable strength design” (ASD) writes:
Load Combination 5. reads  D + 0.7E
Load combination 7 reads   0.6D + 0.7E
Note that E is factored by 0.7, which is equal approximately to 1/1.4 = 0.7 (just as UBC97 requires).

JAE please copy and post for me, from the ASCE 7-95 you have, the complete ASD seismic combinations.

Thank you for your time, I appreciated it very much.

RE: ASCE 7-1995 Seismic Load: factored or not?

All of the seismic combinations (both ASD and LRFD) in 7-95 use the 1.0E in the combo.

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