Performance of Precast Concrete Substructures with Dry Connections to Resist Progressive Collapse

Abstract

In the current study, three one-third scaled beam-slab substructures comprising a cast-in-place reinforced concrete specimen and two precast concrete (PC) specimens were tested under a pushdown loading regime to investigate the effects of connection types on the behavior of PC structures to mitigate progressive collapse. A special link was designed to enhance the connection between PC slabs and PC beams. The test results, including load-displacement curves, ultimate load capacity, ultimate deformation capacity, and local strains, are presented. The failure mode and mechanisms of load redistribution are further discussed. It is demonstrated that the PC specimen with welded connections achieved brittle failure with the lowest ultimate load capacity and deformation capacity. Although the lowest initial stiffness and first peak load capacity were achieved in the PC specimen with pinned connections, its large rotational ability ensured that the specimen failed in a ductile manner, which allowed the development of considerable tensile membrane actions. The main source of the membrane action was from the reinforcement mesh in the topping layer. Despite severe separations occurring between the PC slabs and beams, no PC slab collapsed even though the maximum displacement was larger than double the beam span.