New Shear Connector Design for Insulated Concrete Sandwich Panels Using Basalt Fiber-Reinforced Polymer Bars

Abstract

In this study, 38 push-through tests were performed on a precast concrete insulated sandwich panel design using combined angled and horizontal connectors. Basalt fiber-reinforced polymer (BFRP) and steel connectors were tested and compared. The key parameters were various inclination angles and diameters of connectors; orientation of the diagonal connector relative to loading (i.e., tested in tension or compression); and panels with or without an active foam-to-concrete bond. Steel connectors failed by yielding in tension and inelastic buckling in compression. Larger-diameter BFRP connectors usually pulled out under tension and crushed in compression. Smaller-diameter BFRP connectors ruptured in tension and buckled in compression. Strength and stiffness increased with the connector angle and diameter. The insulation foam bond was found to contribute similarly regardless of connector material. An independent theoretical model accounting for material, bond, and stability failure modes, as well as geometric distortion attributable to relative slip, was developed. It provided an average test-to-predicted value of 1.15 with a standard deviation of 0.25 for the strength of the shear connection system.