Analytical Pushover Method and Hysteretic Modeling of Precast Segmental Bridge Piers with High-Strength Bars Based on Cyclic Loading Test

Abstract

Compared to cast-in-place bridge piers, precast piers can accelerate bridge construction, but their use in seismic systems is challenging. High-strength bars (≥500 MPa) incorporated with precast piers can further expedite joint connection through reducing the quantity of conventional bars. Four large-scale pier column specimens with either high-strength (HRB600) or conventional (HRB400) bars were experimentally studied under cyclic loading. Test results showed that the precast pier with high-strength rebar shows greater lateral strength, self-centering capacity, and total energy dissipation (ED) than the one with conventional rebar. An analytical method was proposed to accurately predict the monotonic pushover behavior. The derivation of the moment-opening angle (M-θ) relationship was presented, considering the slippage between the ED bar and cementitious grout. Furthermore, a fiber-element model was established within the framework of OpenSees. Through modifying the constitutive law of unbonded ED bars near the joint interface, the bond-slip behavior can be realistically simulated. Hysteretic behaviors of precast segmental piers can be accurately captured in terms of maximum lateral force, residual drift, and energy dissipation, among others. The research can promote the application of high-strength reinforcements in the precast segmental pier.