Seismic Tests of Precast Beam-to-Column Joint Subassemblages With Unbonded Tendons

摘要

align="left">Two ungrouted post-tensioned, precast concrete beam-tocolumn joint subassemblages were tested under cyclic reversals of inelastic displacement to determine seismic response. One subassemblage? represented an exterior joint while the other was an interior joint of a one-way prestressed concrete frame. The large scale test units were designed with greatly reduced beam and joint shear? reinforcement compared with equivalent monolithic joints, but with special spiral confinement of the beam plastic hinge regions. Both subassemblages performed well, with only minor, cosmetic damage being recorded? up to drift ratios of 3 percent or more. Energy absorption of the hysteretic response, though small, was larger than expected and residual displacements were negligible. It is concluded that satisfactory? seismic performance can be expected from well-designed ungrouted precast, post-tensioned concrete frames.