Experimental investigation of the flexural and axial load behaviors of concrete sandwich panels

This study experimentally investigated the flexural and axial behaviors of concrete sandwich panels (CSPs). Six large-scale specimens were prepared and tested under three loading conditions: flexural loading, uniform axial compression, and nonuniform axial compression to assess the structural response under stress concentration scenarios. Two 2900-mm-long panels were subjected to four-point bending to evaluate their out-of-plane flexural resistance. Two 500-mm-wide panels were tested under uniform axial compression to determine their axial load capacities. To examine the effect of stress concentration commonly observed near openings in load-bearing CSP walls, two additional 1000-mm-wide panels were tested: one under nonuniform compression, with the load concentrated at the central 500 mm, and the other under uniform axial compression using a stiff steel beam for load distribution, serving as a reference specimen. The results indicate that the CSPs exhibit good out-of-plane flexural resistance, making them suitable for resisting lateral loads such as wind, seismic forces, and earth pressure when used in wall or floor slab applications. The axial load capacity was found to be adequate for multistory buildings; however, a distinct failure mode was observed under nonuniform loading, resembling the failure mode observed in masonry walls under the same action of localized compression loading. The findings from the compression tests suggest that the design recommendations developed for masonry walls under nonuniform compression may serve as a first approximation for CSPs subjected to concentrated compression. Recommendations for future studies are provided to further investigate the key parameters that influence localized compressive loading.