flat slab in zones 3 &4
flat slab in zones 3 &4
(OP)
Hi guys,
Why does the UBC 97 forbid the use of flat slabs in high seismicity zone ?? since it will work as a diaphragm transmitting the forces to the vertical columns, where is the problem ?? Is it because the vertical earthquake ??
Thanks a lot
Why does the UBC 97 forbid the use of flat slabs in high seismicity zone ?? since it will work as a diaphragm transmitting the forces to the vertical columns, where is the problem ?? Is it because the vertical earthquake ??
Thanks a lot





RE: flat slab in zones 3 &4
RE: flat slab in zones 3 &4
Or, as Ron asked, is this a forensic investigation?
RE: flat slab in zones 3 &4
Thanks
RE: flat slab in zones 3 &4
I do not routinely deal with seismic design, so others here can offer more insight.
RE: flat slab in zones 3 &4
Normally I have seen them not recommended in the context of column and slabs only systems against lateral forces, when over some number of floor levels the nodes of the lower floors become unmanageable strained.
RE: flat slab in zones 3 &4
Thanks for ur help.
2nd question :
I dont know if u're familiar with etabs, when u assign stiffness modifier to a shear wall, i generally assign 0.7 to f11, f22, f12 (axial rigidity). The question is : do i use these stiffness to have the reinforcement also or just to check the drift ?? i mean, i was intending to put the modifiers for the slabs and beams and 1.0 for walls. It will make it the wall more dtiff and the reinforcement will be more than if u put 0.7.
What do u think ??
thanks for ur help
RE: flat slab in zones 3 &4
Even though the framing system is taking out your earthquake effects in strength design, there is still inter storey drift between floors that puts extra stress on the slab/column connections for punching shear You have to allow for this as well.