Empirical Design Equation for Compression Strength of Lightweight FRP Sandwich Panel Walls

Abstract

A new empirical design approach is presented for predicting the compression strength of lightweight fiber-reinforced polymer (FRP) sandwich panel columns. The model is simple enough to use for design purposes, yet it considers both local and global failure modes and is able to capture trends observed in experimental results. Insulated FRP sandwich panels present promising energy-efficient solutions for rapid modular construction, including wall or decking applications. To date, no straightforward design method exists for these systems, especially under compression loading, which limits their use in practice. Predicting the load-bearing capacity of these elements is complicated by the fact that several possible failure modes may occur, including global buckling, local wrinkling, face sheet crushing, or core shear failures. The proposed empirical model was calibrated using test results from 168 concentrically loaded sandwich columns with either flax FRP (FFRP) or glass FRP (GFRP) face sheets and polyurethane or polyisocyanurate rigid foam cores. A wide range of material properties, face sheet thicknesses, and slenderness ratios were considered in the analysis. The average experimental-to-predicted ratio was 1.04 with a coefficient of variation (COV) of 0.17.