Seismic response of precast concrete frames with hybrid connections

The analytically simulated performance of moment-resisting precast concrete frames with hybrid connections under seismic loads is evaluated An enhanced and versatile hysteretic model was developed to represent the inelastic behavior of the hybrid precast connection region. The model parameters were calibrated using results from a separate experimental program which examined the inelastic cyclic behavior of hybrid concrete precast connections. An interesting feature of the connection was the hybrid combination of mild steel and post-tensioning or post-tensioning steel where the mild steel was used to dissipate energy by yielding and the post-tensioning steel was used to provide the shear resistance through friction developed at the beam-column interface. To simulate the seismic response of actual buildings constructed with such hybrid precast connections, a series of two-dimensional structural models representing typical four; eight, twelve and twenty-two story precast frames was subjected to a series of earthquake motions. The analyses included 29 different accelerograms, representing all three UBC soil types, and were scaled to fit the UBC design spectra. Results of the inelastic dynamic analyses are used in conjunction with experimental results to develop simple design guidelines for the use of precast concrete hybrid connections in regions of high seismicity