Load Combinations with E and H

[structuralaggie]

I am working on a cantilever retaining wall that has seismic loading that was provided by the Geotech. Looking at stability and the load combination 0.6D+0.7E+H from ASCE7, is it appropriate to reduce E and H by the same amount that D is since they are both functions of D?

 

[COEngineeer]

I thought that's why they put only .6D instead of 1+. I dont think you can reduce it because they already reduce D to .6D.

http://www.krmconsultants.com

 

[structuralaggie]

Well, I am going to have to make a judgement call. I'm not going to reduce E or H, but I am also not going to reduce the resistance the soil provides. I am tying to convince myself that this is not actually part of D. Any thoughts are appreciated. The problem is the dimensions of the wall get rediculous if I go strictly by the load combos.

 

[civilperson]

This paradox appears in this load combination. The entire seismic force is used and the earth force, (which are a function of the mass), and yet the stability from DeadLoad, (D), which is the mass being pulled by gravity), is reduced to 0.6. Not logical but clearly the intent of the code author.