Study on the flexural behavior of precast concrete multi-ribbed sandwich slabs under different boundary conditions

The sandwich slab is a relatively new form of the structural component with the advantages of high-speed erection and insulation function for precast diaphragm systems. Field static loading tests were conducted on eight precast concrete multi-ribbed sandwich slabs with different boundary conditions. The precast concrete multi-ribbed sandwich slab consists of two structural wythes separated by the expanded polystyrene insulation and integrated by evenly distributed longitudinal and transverse concrete ribs. The effects of different volume ratios of longitudinal concrete ribs, numbers of support edges, and types of end connections were discussed to evaluate the cracking mode, stiffness, degree of composite action, and deflection of slabs. The test results indicate that the cracking behavior of the precast concrete multi-ribbed sandwich slabs was similar to that of conventional solid concrete slabs. A higher volume ratio of longitudinal ribs could provide a more effective composite action. Slabs supported on three edges exhibited a more extended linear stage than slabs supported on two edges on load-deflection response. Bolted connections improved the overall flexural performance of the slab through the rotational restraint introduced at the ends of the slab, and bolted angle connections displayed a preferable endrestraining action than through-bolt connections. A theoretical method was developed to calculate the slab deflection under the effect of the bolted connections. In addition, a nonlinear finite element (FE) analysis was performed and validated by the experimental results.