裝設橡膠支承墊於橋梁縮尺模型之試驗與分析

The bridge model tests with rubber bearing

陳皇嘉(Huang-Chia Chen)

指導教授 ： 張國鎮

國立臺灣大學/工學院/土木工程學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.02653

摘要

合成橡膠支承墊廣泛使用於台灣的橋梁工程中，依交通部橋梁設計規範所述，橋梁設計時可以考慮以橡膠支承墊減低地震之影響，但是在橋梁工程中橡膠支承墊是屬於一般支承，並非為抗震機制，因此有關於橡膠支承墊對於橋梁在地震歷時反應中之影響為何
之相關研究並不多，因此更需要透過實驗去了解其特性。
了解橡膠支承墊對於橋梁結構的影響之前，對於橡膠支承墊的基本性質與摩擦性質必須先充分掌握，必需藉由實驗去了解橡膠支承墊的摩擦行為。現今的商業結構分析軟體已具備結構模擬與分析能力(如SAP2000、ETABS、PISA3D等)，各種耐震消能元件也可經由適當的非線性元素加以模擬，但程式中元素的參數是否真能代表結構真實行為還需更多試驗結果的驗證。在本研究中建立解析模型進行分析，並將試驗結果與分析結果作比較，建立合理的數值模型。
由於台灣橋梁工程中橡膠支承墊的施工方式與國外施工方式不同，台灣橋梁工程在施工時合成橡膠支承墊上下面並沒有固定，因此，在1999年台灣集集大地震中，有些裝設橡膠支承墊的橋梁在支承的部份產生滑動破壞的現象，但卻觀察到另外一項特殊的現象，即當支承發生嚴重的滑移現象，下部橋柱的損害反而很輕微，因此說明了支承扮演保險絲角色與力量傳遞路徑的重要性。在本文中建立了一座縮尺橋梁模型，藉由震動台試驗去觀察橡膠支承墊對於橋梁於地震反應的影響，並探討是否有相同於921集集大地震中支承滑動後降低橋柱受力的現象與解析傳力的路徑。

關鍵字

橋樑縮尺模型 ； 橡膠支承墊

並列摘要

This paper is concerned with the mechanical properties and friction characteristics of rubber bearings and their interaction behavior with shear key under seismic loading. In Taiwan, the rubber bearings systems on the bridges are very different from those in the U.S and Japan.To understand the force transmitted from the supper-structure system to substructure, a series of experiments were performed, including cyclic loading tests of bearings, pseudo dynamic tests of a SDOF bridge model and shaking table tests of a scale-down simple supported bridge. In addition, a numerical model built in SAP2000 is used to simulate the test results and to understand the friction-sliding mechanism. The friction coefficient test results show that the friction coefficient of rubber bearing on the concrete surface is close to 0.24 in low velocity, and the one of PTFE-rubber bearing is close to 0.1; the effect on the deformed bearing should be considered to reduce nonlinear shear stiffness for better analysis. The pseudo dynamic test results show that the force transmit from upper part to substructure is a constant as friction force when the rubber bearing slides. Most of importantly, from shaking table tests, it is evident that the strains on the column which is below the bearing with lower friction are smaller than the ones measured on another because of the two different rubber bearing style on two columns. In addition, the strain of both two bridge columns will not be a constant obviously as the pseudo dynamic test result because of the influence of the cap bean inertia force, but it is still obvious that the strain-PGA curve will be gradual when the rubber bearing sliding behavior happens. The shaking table tests demonstrated the lessons learned from minor damaged bridges in Taiwan Chi-Chi Earthquake

並列關鍵字

bridge model ； rubber bearing

參考文獻

中華民國結構工程學會，研究報告 CSSE 84-03A，民國八十五年

1.American Association of State Highway and Transportation

2.American Association of State Highway and Transportation

Officials. Standard Specifications for Highway Bridges.

17th Edition. Washington, D.C.: 2002.