Structural Behavior of Precast Lightweight Foam Concrete Sandwich Panel with Double Shear Truss Connectors under Flexural Load

This paper presents the structural behaviour of precast lightweight foam concrete sandwich panel (PFLP) under flexure, studied experimentally and theoretically. Four (4) full scale specimens with a double shear steel connector of 6？mm diameter and steel reinforcement of 9？mm diameter were cast and tested. The panel’s structural behavior was studied in the context of its ultimate flexure load, crack pattern, load-deflection profile, and efficiency of shear connectors. Results showed that the ultimate flexure load obtained from the experiment is influenced by the panel’s compressive strength and thickness. The crack pattern recorded in each panel showed the emergence of initial cracks at the midspan which later spread toward the left and right zones of the slab. The theoretical ultimate load for fully composite and noncomposite panels was obtained from the classical equations. All panel specimens were found to behave in a partially composite manner. Panels PLFP-3 and PLFP-4 with higher compressive strength and total thickness managed to obtain a higher degree of compositeness which is 30 and 32.6 percent, respectively. 1. Introduction A sandwich panel is a three or more layer element, usually comprising of thin faces/wythes of high-strength material which encloses a thicker inner layer of low average strength. Such sandwich structures have gained widespread acceptance within the aerospace, naval/marine, automotive, and general transportation industries as an excellent way to obtain extremely lightweight components and structures with very high bending stiffness, high strength, and high buckling resistance [1, 2]. Precast lightweight foam concrete sandwich panel (PLFP) consists of two wythe layers of reinforced lightweight foamed concrete with polystyrene as an insulation layer. The layers are bonded by double shear connectors which are embedded through it diagonally as illustrated in Figures 1 and 2. The double shear connectors’ function is to transfer the load applied between the wythes. The degree of compositeness of the wall panel is influenced by the effectiveness of these shear connectors [3]. Figure 1: Precast lightweight foamed concrete sandwich panel (PLFP) with double shear truss connectors. Figure 2: The orientation of steel reinforcement and shear connectors in PLFP. Precast concrete system made from conventional concrete has been developed and introduced into the construction industry and since then has continued to grow in importance. Benayoune et al. have proven in their study that the sandwich precast system which used conventional concrete