摘要過去發生嚴重震害之大地震中，經常可見橋梁遭受嚴重之損害，其中因碰撞效應造成橋梁損害亦十分常見。然而橋梁碰撞效應已有許多研究成果提出，但過去研究的目標橋梁多是以等高橋墩下之水平梁橋為主，較少有具坡度橋梁之相關案例分析。實際上，諸如高架橋匝道、高架道路跨越橋、山區地形變化處之橋梁，橋面坡度變化較大，更甚可達10%。因此本研究將探討碰撞效應對於坡度橋梁之破壞形式及結構動力反應之影響。本研究採用新近發展之向量式有限元素為結構動力分析方法，向量式有限元素適用於處理大變形、大變位、材料非線性與剛體運動等問題，由於橋梁在大地震中，橋梁動力行為不再處於線彈性階段，故必須進行橋梁非線性動力分析甚而預測極限破壞狀態。本研究依日本道路橋示方書設計一座六跨簡支橋梁與一座兩單元三跨連續橋梁為目標橋梁，其支承系統皆使用高阻尼橡膠支承。本研究以不同元素個數模擬橋面板，並變化橋面板坡度，探討碰撞效應對於坡度橋梁之動力行為影響。研究成果顯示，未考慮碰撞效應之橋梁，其橋面板位移及力量較考慮碰撞效應之橋梁大，且橋面板以較多元素模擬的成果較佳。此外，坡度並不會影響橋梁之上部結構落橋數及支承破壞數。而具坡度之連續橋梁之動力行為較簡支橋梁佳。ABSTRACTPounding between decks was observed on most of the bridges which suffered severe damage even unseating. Although the pounding effect of seismically-excited bridges has been studied by many researchers, only few researchers investigated the bridges with inclined decks on this effect. However, the decks of bridges should be of slopes due to various terrain, route alignment and elevation. Occasionally the slope is up to 10%. Therefore, this research is aimed to study the pounding effect of bridges with inclined decks under strong ground motions.The Vector Form Intrinsic Finite Element (VFIFE) is superior in managing the engineering problems with material nonlinearity, discontinuity, large deformation, large displacement and arbitrary rigid body motions of deformable bodies. In this study, the Vector Form Intrinsic Finite Element (VFIFE) is thus selected to be the analysis method.Two types of bridges, a six-span simply-supported bridge and a continuous bridge are analyzed. Both of bridges are with high damping rubber bearings. This study used different number of element to simulate the decks and the deck slopes are from 0% to 10%. The ground motion scales are from 100% to 300%. From the numerical analysis result, the deck deformations and forces without pounding effect are larger than the cases with pounding effect. And more element number is better to simulate the decks. The deck slope does not influence the number of unseating decks and damage bearings. The dynamic behavior of continuous elevated bridge is better than simply-supported elevated bridge under strong ground motion.Keywords: pounding, elevated bridge, vector form intrinsic finite element, high damping rubber bearings.
