Punching Shear Response of High-Performance Fiber-Reinforced Cementitious Composite Slabs

摘要

The response of high-performance fiber-reinforced cementitious composite (HPFRCC) slab panels to punching shear loading was investigated. The slabs were square, 180 mm (7 in.) thick, simply supported at their periphery, and concentrically loaded. Conventional distributed steel reinforcement, if provided, consisted of one or two layers of bottom reinforcement (one- or two-way reinforcement), or four layers of reinforcing bars (two on top and two on bottom, one in each principal direction). The four layers simulated a typical bridge deck designed according to the AASHTO LRFD specifications. Moreover, the effect on punching shear behavior of three different fibers (polyvinyl alcohol [PVA]; ultra-high molecular weight polyethylene identified as SPE; and twisted steel identified as Torex) was evaluated. Test results showed that the punching shear resistance, the energy absorption capacity, and the resistance to spalling of HPFRCC slabs having only two bottom layers of reinforcing bars (one in each direction) were significantly better than for the control specimen with four layers of reinforcing bars and regular concrete., Analysis of the results suggests that the punching shear resistance of HPFRCC slabs with geometric properties similar to those of the test specimens can be safely taken as twice that recommended for design by the ACI code.