Underground Building.

[Tinguindin]

Hello all;

I am designing an underground building which has a length of 200 feet and width of 60 feet. The height of the walls is 29 feet and it will have a dirt cover of 3 feet (The slab will see 3 feet of dirt). EFP pressure from the geo-report is 50 pcf/ft. Seismic is 15 H (inverted triangle). Surcharge is around 100 psf, first ten feet. No groundwater is present.

Per the architect, we are not allowed to put any columns in the middle of the building. So we decided to put columns only around the perimeter, 20 feet on center.

My question is the following;

I will be using a special reinforced concrete moment frame, has anyone design this type of building using a different system?

Thanks.

 

[ishvaaag]

If underground and the "columns" are to be embedded in the mass of the retaining walls I wouldn't conceptuate this as a moment frame. The walls themselves will be taking in shearwall action, along the stiffness of the slab (even wint protruding visible beams), and maybe mat, the seismic forces that in the end origine these categories. If the columns separate from the walls you would have a bit more a case, but I would still think in the same antiseismic behaviour where retaining shearwalls would be predominating in taking the seismic action.

 

[dik]

I would probably use pretensioned T's or Double T's and connect the ends to develop moment. First kik at the kat!

Dik

 

[hokie66]

Agree with ishvaaag. Sounds more like a box of shear walls and diaphragm slabs than a moment frame.