Abstract

An experimental research study was carried out to investigate the life-time performance of unbounded Steel Reinforced Elastomeric Bearings (SREB), which are designed and used for service limit state in bridges, subjected to seismic demands. Such behaviour was investigated using 13 full-scale specimens in three phases; (1) effects of long-term service, namely the long term presence of vertical loading at service limit state, on the mechanical properties of the bearings, (2) effects of consecutive shear loading at different amplitude in presence of permanent loading, and (3) post-earthquake behaviour of the bearing against service load conditions. An innovative test setup was utilized in which the initial situation of the bearings remains unchanged, i.e. bearings do not experience unloading. Using this setup, a realistic loading condition is provided and the contact surface conditions also remain unchanged. It was shown that vertical stiffness, shear stiffness, and damping coefficient of the bearing which are the main parameters of an isolation system, might experience some changes during the life-time of the bearing. However, based on the results obtained, the life-time performance of the SREBs as an isolation system in bridges was evaluated as satisfactory and a durable performance was observed for this type of bearings.

摘要

进行了一项试验研究，以研究无界钢增强弹性轴承 (SREB) 的寿命性能，该轴承设计用于桥梁的服务极限状态，承受抗震要求。使用分三个阶段的 13 个全尺寸样本研究了这种行为；(1) 长期使用的影响，即在使用极限状态下长期存在垂直载荷对轴承机械性能的影响，(2) 存在永久载荷时不同振幅的连续剪切载荷的影响，以及 ( 3) 轴承在使用载荷条件下的震后行为。使用了一种创新的测试装置，其中轴承的初始状态保持不变，即轴承不会卸载。使用此设置，提供了一个现实的加载条件，接触面条件也保持不变。结果表明，作为隔震系统主要参数的轴承的垂直刚度、剪切刚度和阻尼系数在轴承的使用寿命期间可能会发生一些变化。然而，根据获得的结果，SREB 作为桥梁隔离系统的寿命性能被评估为令人满意，并且观察到此类轴承的耐用性能。