Effects of grout sleeve defects and their repair on the seismic performance of precast concrete frame structures

Abstract

Precast concrete frame structures with grouted sleeve connections are widely used. An experimental study was conducted investigating the seismic performance of precast concrete frame structures having backflow defects in their grout sleeves. Repair of such defects is also demonstrated using a simple grout injection technique. Four two-storey precast concrete frame structures having grout sleeve connections in their columns were designed and tested under reversed cyclic loading. The performance of frames having no grout defects and those with defects and repaired defects is described in terms of failure modes, hysteresis characteristics, load-carrying capacity, ductility and energy dissipation capacity. The results indicate that the plastic collapse mechanism of the frames remains unchanged, the performance is affected by the presence of the grout sleeve defects. Despite the defects only reducing the capacity of one of three columns in the frame either 6% or 19%, the effect on the global behavior of the frame was evident in terms of reduced capacity, stiffness, ductility and energy absorption. Injecting grout into defective grout sleeves restored their capacity, and that of the frames, to a defect-free condition.