Punching Strengths of Flat Plates with Vertical or Inclined Stirrups

The shear reinforcement of flat plates involves problems in both design and execution. This paper introduces a novel form of inclined stirrups that is simple to make and to install, and reports the results of tests of slabs with such reinforcement. Companion tests of slabs without shear reinforcement and slabs with vertical stirrups are also reported. The inclined stirrups are shown to function well and pro-duce punching resistances superior to those obtained with vertical stirrups. Comparisons are made between the experimental results and predictions based on both ACI 318-95 and the CEB-FIP Model Code MC90, and proposals are made for improving the lat-ter design method.