A Type III grouted seismic connector for precast concrete structures

摘要

The results from an experimental investigation of a novel tapered, cylindrical grouted Type III connector for ductile, energy-dissipating, deformed reinforcing bars in gap-opening joints of seismic precast concrete structures are presented. This Type III connector offers the potential for a high-performance yet simple, nonproprietary, low-cost system that allows energy-dissipating bars under cyclic loading to reach close to their full ultimate strength and strain capacity in tension over a short, grouted embedment length. The use of short grouted connections simplifies the construction of precast concrete structures because protruding bar lengths from precast concrete members are minimized and field-grouting lengths are reduced. Six energy-dissipating bar specimens were subjected to a rigorous uniaxial cyclic loading history inside a grouted sleeve. Five of the bars achieved ductile fracture (without pullout) and one bar (with slightly lower connector grout strength) failed through ductile pullout at maximum strains close to the monotonic tension strain capacity corresponding to the ultimate (maximum) strength of the bar.