Glass fiber–reinforced polymer (GFRP) shear connectors provide much reduced thermal bridging in insulated concrete sandwich panels compared to steel connectors. In this study, 50 specimens with dimensions of 254×254×900 mm representing segments of a precast sandwich wall comprising two concrete wythes and a concrete stud surrounded by insulation foam have been tested in a double-shear configuration. Three types of GFRP connectors produced from available sand-coated and threaded rods were tested and compared to conventional steel and polymer connectors. GFRP connector diameters varied from 6 to 13 mm, and spacing varied from 80 to 300 mm. Both circular and rectangular cross sections were examined, along with various end treatments to compare with simple straight embedment. The shear strength of GFRP connectors, including the effect of friction between concrete and foam, ranged from 60 to 112 MPa, significantly higher than polymer connectors but lower than steel connectors. As the connectors bridge...

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 ge...