橋樑下部結構破壞模式及維修方法之研究—以高雄縣莫拉克颱風災害為例

Investigation of Failure Modes and Repairing Method for the Substructure of Bridge─Case Study of Typhoon Morakot Disaster in Kaohsiung County

　　2009年莫拉克颱風帶來創紀錄的雨量，造成台灣中南部地區發生嚴重水災及大規模的土石流(debris flow)，釀成重大的災害，莫拉克颱風侵台期間，不僅降下創歷史新高之雨量記錄，其所造成公路橋樑斷橋數量亦是前所未有。根據交通部颱風災後統計，莫拉克風災總共造成高雄、屏東、台東地區省道計有50座橋樑損壞、斷裂；其中以公路總局轄屬之台17線雙園大橋S2~S16遭洪水沖毀流失約459公尺，造成高雄屏東兩地之交通中斷，導致經濟重大損失。本研究係探討橋樑下部結構破壞模式及維修方法，以高雄縣境內受莫拉克颱風災害之橋樑為研究對象，並以文獻探討、專家諮詢問卷調查等研究方法加以探討。研究結果顯示，颱風造成公路橋樑下部結構破壞模式主要為橋台或橋墩基礎遭受洪水沖刷或土石流沖擊，造成基礎掏空裸露而導致沉陷或傾斜等破壞，導致橋樑上部結構發生落橋、坍塌等災害最為常見；而橋樑下部結構維修補強方法之選擇，主要以基礎部分之增樁擴座補強工法、橋墩柱部分之鋼板包覆補強工法及橋台部分之地錨補強工法等較為常用。

關鍵字：莫拉克颱風、下部結構、破壞模式、維修方法。

ABSTRACT

　　In 2009, Morakot Typhoon bring record rainfall, resulted severe flooding and Large-scale debris flow in central and southern Taiwan, Morakot Typhoon caused the most unprecedented quantity highway bridge fault ever. According to the institute of transportation,MOTC to Morakot Typhoon disaster statistics. This investigation of failure modes and repairing method for the substructure of bridge, case study of Typhoon Morakot disaster in Kaohsiung county, and to literature investigation, expert consultation and questionnaire research methods to explore. The results show, failure modes for the substructure of bridge of mainly abutment or pier foundation subjected to the impact of flood erosion and debris flows, emptying caused by the exposed foundation or tilt caused subsidence damage, the most common of the superstructure of bridge to fall and collapse disasters. Repairing method for the substructure of bridge for the choice, mainly increase in pile and spread foundation reinforcement construction method, bridge pier, bridge column coated steel reinforcement construction method, and abutment ground anchor reinforcement construction method more common.

Keywords: Morakot Typhoon, Substructure, Failure Modes, Repairing Method.