ASCE 7-05 12.4.2.2 vertical seismic load effect on foundation design
ASCE 7-05 12.4.2.2 vertical seismic load effect on foundation design
(OP)
Ev=0 is required for those load combinations containing Eh-Ev when checking "soil-structure interface of foundations". I am not sure about this terminology at all. Does soil-structure interface demand cover all checks such as ground bearing, overturning and sliding?
My second question is: why Ev=0 is not applicable for E=E+Ev. Or, what are the design implications in terms of signs of Ev (seismic uplift force).
I wish to thank you all in advance.
My second question is: why Ev=0 is not applicable for E=E+Ev. Or, what are the design implications in terms of signs of Ev (seismic uplift force).
I wish to thank you all in advance.






RE: ASCE 7-05 12.4.2.2 vertical seismic load effect on foundation design
But, my take on it is that the Ev doesn't really need to be considered for cases where you're looking at 0.6*DL for overturning / uplift and such for the foundation. The DL really is artificially reduced in those cases (to provide a 1.5 overturning safety factor).
It would seem to be overkill to require even more uplift / overturning for those seismic cases. In fact, I believe the 1997 UBC had a restriction that the vertical component of earthquake did not need to be considered at all for ASD load combinations.
RE: ASCE 7-05 12.4.2.2 vertical seismic load effect on foundation design