Flexural behavior of composite concrete slabs reinforced by FRP grid facesheets

Composite concrete slabs reinforced by fiber-reinforced polymer (FRP) grid facesheets (CFGF slabs) are a new form of structural member, consisting of FRP facesheets as the bottom face of the slab, square FRP grids on top of and molded together with the FRP facesheets, and a top layer of concrete. In this novel slab, FRP and concrete are optimally combined to obtain several advantages: (1) the CFGF slab may be constructed in-situ or precast, with the FRP grids and facesheets acting as the stay-in-place form; (2) the FRP grids and facesheets act as reinforcements when the slab is under bending; (3) excellent corrosion resistance is expected due to the presence of the FRP grid and face sheet. This paper presents an experimental study of CFGF slabs subjected to four-point bending. Three groups of CFGF slabs were fabricated and tested to investigate the effects of grid rib spacing, grid rib height and facesheet thickness. A section transformation method was used to evaluate the overall bending stiffness and the midspan deflection of the CFGF slabs. Comparisons between experimental results and analytical predictions showed that this method accurately predicted the bending stiffness and midspan deflection as well as the ultimate capacity of CFGF slabs.