Resetting Response of Precast Segments with Gently Keyed Interface under Seismic Action

Abstract

In an attempt to promote the use of precast segmental bridge columns in regions of moderate to high seismicity,sliding planar joints have been adopted to relieve the adverse effects of seismic action. However, despite the ability to survive an earthquake, the sliding segments often result in noticeable residual relative movements afterwards, which require costly repairs. To better understand the kinetic and self-centering performance of sliding segments with W-shaped gently keyed interface, the concept of sliding hysteresis center curve is put forward. A bidirectional asymmetrical pure sliding model is explored for better control of the self-centering ability, where the downslope slip caused by the energy at the post-peak stage of an earthquake may benefit the self-centering performance of asymmetrical sliding systems. A series of parametric studies using real earthquake records are then conducted to evaluate the effects of inclination θ and coefficient of friction μ at the interface on the dynamic response. It is found that the seismic excitations, especially the post-peak cycles, have profound influence on the residual displacement of an asymmetrical sliding system. With proper design, a W-shaped gently keyed sliding system can provide superior self-centering performance without affecting its seismic isolation ability during the peak stages of earthquakes.