Performance of Bridges Isolated with Sliding-Lead Rubber Bearings Subjected to Near-Fault Earthquakes

Abstract

This paper investigates the seismic performance of bridges installed with a sliding-lead rubber bearing (LRB) isolation system subjected to near-fault earthquakes. A three-span continuous bridge isolated with sliding-LRB system is used as an example. Nonlinear time history analyses are conducted to investigate the sensitivity effects of isolation period, friction coefficient and sliding displacement limit on the bridge responses. The responses of the sliding-LRB system are compared with those of the conventional LRB system. The results show that the base forces of the piers can be reduced by employing proper friction coefficients. However, the residual displacement of the sliding-LRB system may be larger compared with that of the conventional LRB system. To overcome this disadvantage, an improved solution to reduce the residual displacement is proposed with its effectiveness investigated. It was also demonstrated that the residual displacement and peak displacement can be effectively reduced by employing the shape memory alloy devices in the sliding-LRB system without significantly increasing the base forces.

Multi‐stage superelastic variable stiffness pendulum isolation system for seismic response control of bridges under near‐fault earthquakes

“…Compared with friction pendulum bearing, the pure‐friction sliding bearing shows much less sensitivity to the earthquake spectral characteristics 16 and can also address the thermal deformation of the superstructure by sliding freely and suppress the seismic shear to be maximum friction force 17,18 . In view of the advantages of the pure‐friction sliding bearing, the sliding‐lead rubber bearing has been developed by combining the lead rubber bearing with the pure‐friction sliding bearing in series to improve the adaptability 19,20 . However, the experimental results show that the hysteretic behavior of the sliding‐lead rubber bearing depends on the relationship between the friction force of the pure‐friction element and the yield force of the LRB element 20 .…”

“…As discussed above, the friction pendulum bearing with variable curvature can efficiently enhance the bridge seismic performance compared with the traditional friction pendulum bearing 11,12 . Meanwhile, the pure‐friction sliding bearing can effectively accommodate thermal deformation from superstructure under service loadings 17,20 . It is necessary to develop the resilient isolator by combining the advantages of superelastic SMA, pure‐friction sliding isolator and friction pendulum isolator.…”

Influence of Restrainer Piers on the Seismic Performance of Long Bridges with Equal-Height Piers

“…e experimental results demonstrated a substantial improvement in the ability of the isolated bridge to sustain all levels of seismic excitation under elastic conditions [27]. Seismic performances of bridges installed with a conventional lead rubber bearing (LRB) system and sliding-LRBs were investigated under near-fault excitations [28,29]. By combining SMA wires with sliding-LRBs, thus forming a superelastic-sliding-LRB isolation system, different studies have indicated that the displacement responses can be effectively mitigated [30].…”

Study on the Seismic Performance of Different Combinations of Rubber Bearings for Continuous Beam Bridges

“…Li et al [2] performed the shaking table array test of a two-span isolated continuous bridge specimen with the scale of 1 : 3 to study the seismic response characteristics of the continuous bridge with HDR bearings. Zheng et al [21] investigated the seismic performance of the bridges with a sliding-lead rubber bearing (LRB) isolation system under the action of near-fault earthquakes. For the bridges with tall piers, Chen and Li [11] investigated the effect of different seismic retrofitting measures including LRBs and rocking foundations on mitigation of their seismic responses.…”

“…Additionally, the continuous beam bridge with a combination of different bearings has more complicated response to earthquakes because (1) LRBs and HDRBs have nonlinear horizontal stiffness, quite different from NRBs especially at high shear strain amplitudes, and (2) some factors, such as pier height and span length, also influence the seismic performance of the bridges [24][25][26]. Researchers have investigated the failure modes and seismic performance of a continuous beam bridge with a combination of different bearings during strong ground motions [21,27]. However, the influencing factors are studied very rarely based on a combination of different bearings.…”