Flexural behavior of precast insulated sandwich wall panels: Full-scale tests and design implications

Abstract

This paper focuses on a new type of precast sandwich wall panels in which the expanded polystyrene (known as EPS) insulation layers are inserted between exterior reinforced concrete panels. The exterior reinforced concrete panels are held through diagonal steel bars to allow the sandwich panel to form the composite action to resist the bending moment demands. To investigate flexural behavior of the sandwich wall panels, four specimens with representative geometries and typical materials were designed. The four specimens included one with the flat exterior reinforced concrete panels and three with the ribbed exterior reinforced concrete panels. The specimens were tested using gradually increased uniformly distributed loads. It is found that all the specimens developed the composite action when resisting the bending moment demands and exhibited the same failure mode. Test results show that the specimens consisting of the ribbed exterior reinforced concrete panels (which had lower mass per unit volume) exhibited reduced flexural resistances at the cracking limit state and the ultimate limit state in comparison with the one with flat exterior reinforced concrete panels. This paper develops a set of analytical models based on the test data and simplified strain/stress diagrams for analyzing flexural behavior of the proposed sandwich wall panel. Result comparisons show that the models can provide reasonable predictions and they can be used for future practice.