橋梁耐洪能力提升之下構改建工法-以台88線萬大大橋橋基補強工程為例

Abstract

本論文提出有別於以往之下構補強工法，而是對下部結構進行改建：利用先建後拆之方式，於原結構側邊建立新門架式下部結構，施拉預力；待力量轉移後拆除原橋柱以達到下構改建之目的。 本論文利用三維立方元素(3D solid element)進行施工步驟模擬分析，以瞭解改建時力量轉移之行為及新舊混凝土間之各種力量傳遞，並提出一較簡易之二維框架(2D frame)分析，以便用於工程上之分析及設計。預力鋼腱配置線形主要係抵抗拆除舊橋柱當時之反力，而新舊混凝土介面主要係利用化學錨筋及預力鋼棒接合，使所有力量能均能傳遞至原帽梁混凝土內。

This paper proposed a new substructure reconstruction technique. We constructed new piles and foundations which are located between and on the left and right hand side of the old ones. New cap beams are built to switch forces into the new substructure. At the end, the old substructure can be removed. If the construction space is limited, prestress technique can be applied. This paper studied the force transformation mechanism of the proposed technique with 3D solid element and 2D frame analysis, and we expect to provide a save and feasible technique for solving erosion problems.