Shear Behavior of Parallel Special-shaped PBL-steel Fiber Reinforced Concrete Composite Shear Connection

Abstract

To promote application of PEL connectors in fabricated composite beams, a parallel special-shaped PBL-steel fiber reinforced concrete (SFRC) composite shear connection is proposed. Taking the number of steel bars in the connection as a parameter, 5 simplified unilateral push-out specimens are tested, and their failure modes and load-displacement curves are obtained. The key deformation characteristics of the shear performance of the specimens arc compared and assessed. Based on the test results, a finite element (FE) model is established after a careful calibration against the test results. The "stress and strain" development and distribution of various material components in the FE models are analyzed. A preliminary study on the fracture mechanism of the special-shaped steel connector is carried out. Through this study, it is found that the parallel special-shaped PBL-SFRC composite shear connections have the advantages of large initial shear stiffness and high ductility. The configuration of steel bars can effectively prevent the longitudinal splitting damage in the SFRC, and reduce the pull-out effect of the connectors. Integrity of the composite connection increases with an increase in the number of steel bars. The failure mechanism of these connections is well simulated by the FE analyses, i. e., the failure of the connection is initiated the yielding of PBL connector, then the damage of SFRC, and ultimately the fracture of PBL connector. The fracture point of the PBL connector is found to have a large steel strain in the FE model, and it agrees well with the steel necking strain.