Shear Behavior of FRP Connectors in Precast Sandwich Insulation Wall Panels

Glass fiber reinforced polymer (FRP) composite connectors used in precast sandwich insulation wall panels directly affect the safety of the wall. In practical applications, a precast concrete sandwich insulation wall panel is transported to the construction site for hoisting 3–5 days after steam curing, and its concrete strength typically reaches approximately 70% of the design strength (i.e., the concrete strength after natural curing for 14 days). This study investigated the natural curing of concrete for 14 days and analyzed the mechanical properties of FRP connectors with two different sections in terms of their failure mode, failure process, and load–displacement curves. Numerical analysis and finite element parametric analysis of the connectors were conducted based on experimental data. The average ultimate shear capacity of a single rectangular-section connector was 8.37 kN and that of the cross-section connector was 8.37 kN. The connectors exhibited a good shear resistance, and the rectangular-section connectors had better ductility than the cross-section connectors. The wall panel exhibited three types of failure modes: splicing failure of the fiber layer of the connector, fiber fracture in the anchorage of the connector, failure of the concrete of the anchorage, and mainly material damage of the connector itself. The error between the load simulation value and test value of a single connector was less than 10% of the numerical simulation error requirement, and the finite element simulation results were reliable. The results of the parametric simulation of the shear capacity showed that the distance between connectors, anchorage depth, and insulation layer thickness had a significant influence on the shear performance of concrete connectors.

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