橋梁功能性支承系統之位移解析與振動台實驗研究

本研究採用狀態空間法提出橋梁含功能性支承系統之位移解析流程，並經由振動台實驗成果驗證研提方法獲致良好準確性。分析模式係將橋梁簡化為雙自由度系統，其特點為考慮橡膠支承墊於黏著及滑動狀態間之非線性變化過程，有效分離支承剪力變形量與滑動變形量。為驗證解析模式之合理性，本研究進行單跨簡支梁橋振動台實驗，檢討橡膠支承墊之勁度、摩擦係數與阻尼比設定方式。分析結果顯示，支承有效勁度應取為剪應變之函數而非定值；靜摩擦係數約0.5、動摩擦係數約0.35；未滑動時之固有阻尼比約7%。如根據前述參數，上部結構於地震作用時之位移與加速度歷時，包括最大位移、殘留變形及最大加速度均可有效評估，未來可用於檢討支承防落長度及橋柱設計剪力需求。

關鍵字

橋梁；橡膠支承；摩擦係數；狀態空間法；振動台實驗

並列摘要

This study presented a state-space based analytical method to predict the displacement demand for bridge with functional bearing system, and its accuracy was successfully verified by the shaking table test results. A simplified twodegree- of-freedom system was adopted to account for the stick and sliding states of the rubber bearing, so that shear and sliding deformations of the rubber bearing were differentiated. Besides, in order to examine the rationality of the proposed approach, a shaking table test of a simply-supported bridge model was carried out to obtain the properties of laminated rubber bearing, including lateral stiffness, friction coefficient, and inherent damping. It was founded the lateral stiffness should be defined by a function of lateral shear strain, rather than a constant value in all seismic events. The static and dynamic friction coefficient for rubber against concrete surface are about 0.5 and 0.35, respectively. The inherent damping is 7% on average before sliding. The parameters mentioned above were applied into the proposed simulation model. It is confirmed the maximum and residual displacement as well as the maximum acceleration of girder were effectively predicted. In the future, both unseating length and shear force demand could be further investigated by the proposed model.

並列關鍵字

bridge ； rubber bearing ； friction coefficient ； state-space method ； shaking table test

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橋梁功能性支承系統之位移解析與振動台實驗研究

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