Structural performance of precast–prestressed hollow core slabs subjected to negative bending moments

Abstract

The precast–prestressed hollow core slabs (HCS) are generally designed as simply supported one-way slab without any negative moment. It may be required to have an overhanging part of the slab to act as a cantilever in various projects, so the slabs will be subjected to negative bending moments. The main objective of the current research is to enhance the performance of precast–prestressed HCS when they are subjected to negative bending moments. An experimental program was designed to construct and test six full-scale slabs with overhanging part. One slab was tested as a control slab without strengthening materials. Three slabs were strengthened with CFRP and GFRP strips and two slabs were strengthened by near surface-mounted GFRP and steel bars. A finite-element program was used to simulate the tested slabs and it gives good results compered with the experimental results. In addition, the results showed that the slab strengthened by four layers of GFRP as strips achieves the highest structural performance compared to the other strengthened slabs and it gives the maximum ductility ratio and energy observation.