Two-way flat ribbed slabs with shafts

Resumo

The position of pipes and hoses for several installations still deserves special attention from designers mainly when the failure mode of them can be modified due to changes of service behavior. This work compares experimental results of six two-way reinforced concrete flat ribbed slabs with rectangular holes close to columns and without shear reinforcement with the estimates of the codes ACI 318 and NBR 6118. All slabs were casted and tested in the Civil Engineering Laboratory of UFPA and had dimensions of 1.800 mm x 1.800 mm x 150 mm submitted to a central loads applied through 120 mm side square steel plates simulating the columns. EPS was used as inert material and the ribbed were spaced of 250 mm with 130 mm height and 75 mm average wide. The results showed that the shear codes’ estimates agree when the ribs are individually considered as beam and for punching, but trend to be safer when the slabs present two shafts.