Shaking table tests of a reinforced concrete bridge pier with a low‐cost sliding pendulum system

Abstract

Summary After the occurrence of various destructive earthquakes in Japan, extensive efforts have been made to improve the seismic performance of bridges. Although improvements to the ductile capacities of reinforced concrete (RC) bridge piers have been developed over the past few decades, seismic resilience has not been adequately ensured. Simple ductile structures are not robust and exhibit a certain level of damage under extremely strong earthquakes, leading to large residual displacements and higher repair costs, which incur in societies with less‐effective disaster response and recovery measures. To ensure the seismic resilience of bridges, it is necessary to continue developing the seismic design methodology of RC bridges by exploring new concepts while avoiding the use of expensive materials. Therefore, to maximize the postevent operability, a novel RC bridge pier with a low‐cost sliding pendulum system is proposed. The seismic force is reduced as the upper component moves along a concave sliding surface atop the lower component of the RC bridge pier. No replaceable seismic devices are included to lengthen the natural period; only conventional concrete and steel are used to achieve low‐cost design solutions. The seismic performance was evaluated through unidirectional shaking table tests. The experimental results demonstrated a reduction in the shear force transmitted to the substructure, and the residual displacement decreased by establishing an adequate radius of the sliding surface. Finally, a nonlinear dynamic analysis was performed to estimate the seismic response of the proposed RC bridge pier.

Bidirectional shaking table tests of a low‐cost friction sliding system with flat‐inclined surfaces

“…As observed in a previous work, 12 concrete is susceptible to damage under dynamic motions. In this previous study, repetitive excitation caused concrete powdering and increased friction.…”

“…As a solution, flat surfaces would deal with those negative aspects of concave surfaces. Large seismic energy can be dissipated because of its perfect plastic behavior and can eliminate fluctuation of axial loads compared with a concave F I G U R E 1 Original system for unidirectional motion 12 [Colour figure can be viewed at wileyonlinelibrary.com] shape. A simple flat surface would transmit low axial pressure to the concrete surfaces; however, because of the lack of restoring force, the bidirectional excitation is severe for sliding 13 and leads to an undesirable residual displacement.…”

“…However, the cost‐benefit of using advanced materials to ensure the seismic resilience of structures has not been well‐determined. Figure shows a novel RC bridge pier with a low‐cost sliding system, originally proposed in a previous study . This system utilized conventional concrete and steel to achieve a low‐cost design solution that maximized post‐event operability.…”

“…Figure 1 shows a novel RC bridge pier with a low-cost sliding system, originally proposed in a previous study. 12 This system utilized conventional concrete and steel to achieve a low-cost design solution that maximized post-event operability. The isolation performance of this original system was based on the principle of FPBs.…”

Review of annual progress of bridge engineering in 2019

“…When studying the seismic performance of the long-span pile foundation cable-stayed bridge, Sun and Xie 2019 To study the seismic performance and isolation effect of the traditional friction swing bearing (FPB) and the new three friction swing bearing (TFPB) isolation bridge, Wen et al (2019a) conducted shaking table tests on the 1/10 scaled FPB and TFPB simply supported beam bridge models under the excitation of a two-direction earthquake. Brito et al (2019) evaluated the seismic performance of a new type of reinforced concrete bridge pier with a low cost sliding pendulum system through a one-way shaking table test. Zhou et al (2019f) conducted shaking table tests on a 1/10 scaled single span bridge, and studied the seismic response and shaking isolation effect of the bridge with a post-tensioned swing pier with negative swing stiffness.…”