Earthquake Collapses Hualien Bridge 高寮大橋梁柱斷裂 橋面崩塌於河床上

Hualien's Gaoliao Bridge sustained extensive damage in the 918 earthquake. A research team from National Chung Hsing University took aerial photos of the scene using a drone and then used high-speed computer image processing technology to create a 3D model for the government and civic groups to use for disaster survey and reconstruction work.

The bridge's beams and columns have broken apart, exposing steel reinforcing bars. Meanwhile, the bridge deck collapsed onto the riverbed. This is Hualien's Gaoliao Bridge, which was at the epicenter of the 918 earthquake and sustained extensive damage.

Yang Ming-der, Distinguished Professor, Dept. of Civil Engineering, NCHU: “To help with disaster relief, we produced this 3D model just one hour after getting the aerial images.”

In the past, 3D imaging technology was used in the survey of major disasters. It wasn't easy and also risky to investigate the bridge's damage at the scene, so a National Chung Hsing University research team used a drone to capture high-res images on Sept. 19 and image processing technology to create a 3D model. This model shows what kind of damage the bridge sustained and where. The team also set up a website to provide this information for free for use in disaster survey and reconstruction work.

Yu Chih-peng, Dep. Chair, Dept. of Civil Engineering, NCHU: “You can see everything all at once. If you go to the scene, you'll only be able to stand on certain parts to see. This thing offers the opportunity for a comprehensive view.”

The Hualien County Government has so far determined that six bridges were damaged by the earthquake, including Gaoliao Bridge. Two suffered severe damage and will need to be rebuilt. Three others need repairs. The total cost is estimated at NT$3 billion and the county government has applied to the central government for funds.

Teng Tzu-yu, Director, Economic Affairs Dept., Hualien County: “If they're going to be rebuilt, they'll have to conform to the length and height in the existing river management plan. The bridge width also needs to conform to current highway design standards.”

The county government said new bridge designs must be thoroughly evaluated, but it's hard to predict how long the construction will take. It has asked residents to make detours in the meantime and will do its best to accelerate the reconstruction work.

橋樑樑柱斷裂鋼筋外露，橋面倒塌在河床上，雖然不在現場，但可以清楚看見橋樑受損的樣貌和細節。而這座橋樑正是918地震中，倒塌的花蓮高寮大橋。

中興大學土木工程系特聘教授楊明德表示：「這次為了緊急救災，我們拿到空拍照片之後一個小時，就把3D模型做出來。」

3D的影像技術，以往已經應用在大規模災害調查。這回918大地震中高寮大橋倒塌，但現場勘災不易，加上風險高，中興大學的研究團隊在19日取得高解析的空拍相片後，以影像處理技術建立3D模型，呈現橋樑破壞型式和相關位置，並建置網站公開模型資訊，成為勘災和重建作業的資料庫。

中興大學土木工程系副主任余志鵬說：「一次就可以看到，甚至於到現場的人，他本來只能局部站在某些位置去看它，有了這東西後，他是有全觀的一個機會。」

花蓮縣橋樑受損的部分，縣府統計目前有6座橋樑受損。其中除了高寮大橋倒塌，崙天大橋和玉長大橋也因為受損嚴重，必須整個重建。另外包括玉興橋、長富大橋和萬寧陸橋也需要修繕，總金額估計約30億，已經報請中央申請災害準備金。

花蓮縣建設處長鄧子榆說：「既然要重建了，它就是要符合這河川既有的治理計畫的長度、高度，另外橋梁的寬度也要符合現今公路設計標準。」

花蓮縣建設處表示，新建橋樑設計必須作完整工程面評估，但工期還難以估算，目前只能請當地居民繞道之外，也會積極加快重建腳步，減低交通的衝擊。