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 Wshaped 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 selfcentering 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 postpeak 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.

Cyclic Bond-Slip Behavior of Partially Debonded Tendons for Sustainable Design of Non-Emulative Precast Segmental Bridge Columns

“…Moreover, the segments also have the tendency to slide back to the original relative position under the subsequent excitations of smaller magnitudes to achieve satisfactory self-centering performance as if the dislodged segments are reset at the joints upon cessation of an earthquake, thus achieving high resilience and great sustainability toward seismic hazards. In particular, the resettable sliding joint [24] consists of three major components as shown in Figure 2: (i) durable low-friction concrete-to-concrete contact surfaces [26]; (ii) non-planar contact surfaces with gentle guide keys [27]; and (iii) partially debonded tendons with low initial prestress.…”