ASCE 7 Cl. 12.4.2 & 12.5.4

Question

ASCE 7 Cl. 12.4.2 & 12.5.4

hveng77 (Structural)

(OP)

12 Oct 12 09:12

I am designing a steel structure in Seismic Design category E using Equivalent Lateral Force procedure. As per Cl. 12.5.4, I should consider 100% seismic load in one direction + 30% seismic load in perpendicular direction.
As per Eq. 12.4.1/12.4.2, I should also consider Ev+-Eh.
Should I apply 30% Ev while combining it with Eh, i.e. 100%Ehx + 30% Ehz + 30% Ev? Or should I consider full effect of vertical seismic load, i.e. 100%Ehx + 30% Ehz + 100% Ev?

JAE (Structural) · Answer 1 · 2012-10-12 10:54:13

My first thought would be to use 100%Ehx + 30% Ehz + 100% Ev but I'm not near the code right now.

hveng77 (Structural) · Answer 2 · 2012-10-15 05:24:01

Thanks JAE.
When you have a moment, could you pleae look into the code and let me know your views.

MrHershey (Structural) · Answer 3 · 2012-10-15 13:26:55

100%. Code actually handles vertical seismic load by using a fraction of the dead load and dumping it in with dead load in the combinations (see 12.4.2.3), so should always be 100% Ev barring either of the exceptions listed in 12.4.2.2, whether you have orthogonal loading or not.

hveng77 (Structural) · Answer 4 · 2012-10-17 07:03:09

Thanks MarkHirschi for your response.

Regards
H

Come Join Us!

Posting Guidelines

Related Projects

Jobs

ASCE 7 Cl. 12.4.2 & 12.5.4