Experimental and numerical investigations on shear behavior of high-strength bolted connections after impact

Abstract

For structures subjected to extreme loading, such as impact, the plastic deformation of structural connections is vital to life safety. Despite its importance, a loss of deformation capacity in connections via fracture of bolts has been repeatedly noted experimentally and in situ. To further investigate the residual strength of high-strength bolted connections after impact damage, this paper presents investigations on shear performance of high-strength bolted connections. This is the first study to report strength and deformation performance for structural bolts after impact damage. A total of 144 specimens were tested for the study, with varying impact height, steel plate thickness, bolt shank diameter, and high-strength bolt grade as the main variables. Experimental results involving failure modes, strain development, and effect of parameters are presented in detail. The observed failure mode is typical bolt shear failure, characterized by extrusion deformation around the bolt hole. The increasement of the thickness of steel plate, the diameter of bolt shank, and grade of bolt would improve the ultimate strength. The shear stiffness is positively correlated with impact height, thickness of steel plate and grade of bolt, but the ductility is decreased with the increment of thickness of steel plate. In addition, the results obtained from the finite element simulation are in agreement with the experimental findings. The simulation analysis shows that the specimens after impact damage are different from those of conventional specimens. Parameters formulae are then proposed with sufficient accuracy for the ultimate strength of high-strength bolted connections with impact damage.