Built-Up Fiber-Reinforced Polymers (FRP) Profiles with Improved Shear Performance for FRP–Concrete Hybrid Section

Abstract

Fiber-reinforced polymer (FRP)–concrete hybrid sections, composed of FRP profiles and a concrete slab, have gathered attention in construction due to their lightweight, easy installation, and high durability. However, the low shear strength and brittle behavior of commercially available pultruded FRP profiles often leads to brittle shear failure at low load levels. To enhance the shear strength and ductility, this study proposes a novel H-shaped FRP profile that is built from two U-shaped pultruded FRP profiles and a hand lay-up sandwiched core of multi-directional fibers. Direct shear tests showed that the built-up FRP profiles failed in pseudo-ductile mode while the U-shaped pultruded FRP profiles failed in brittle mode. Built-up FRP had 1.5 times the capacity and 2.8 times the ultimate redundancy compared to pultruded FRP. Additionally, flexural tests of FRP–concrete hybrid beams revealed that the webs of the built-up FRP profiles failed in a higher shear capacity with smeared cracks.