| 摘要: | 當斷橋事件發生時，橋上的行車可能會因暴雨導致視線不良，或是無法確實掌握前方橋梁的健康情形，依然駛向斷橋處，導致人車危安事件的發生。本論文旨在建立一具有可靠性、經濟性、維護性、簡易性之斷橋警示系統，沒有繁複的監測資料回傳與複雜的計算理論，僅以斷橋事件發生的有或無作為判斷依據，當斷橋事件發生時，能夠確實警示橋上用路人，避免造成更多不必要的人車損害。
本論文建立兩套斷橋警示系統，分別為水力式警示系統和電路式警示系統。水力式警示系統以放置在水箱中的水位控制器作為偵測元件，將PVC水管連接水箱出水口至梁間縫隙處，當梁間產生相對位移時，安裝在梁側的剪切裝置能夠剪斷水管，使水箱內的水位下降，以重力拉動水箱內的水位控制器，切換內部接點，達警示效果。電路式警示系統以電導線配合繼電器作為偵測元件，於橋體單元結構如大梁、橋墩上佈設與錨固電導線，當橋體單元之間產生巨大的相對位移、旋轉時，產生拉扯力扯斷導線，此時可藉由繼電器的的控制系統與被控制系統的特性，觸發警報達警示效果。
本論文亦藉由交通部運輸研究所之公路跨河橋梁沖刷潛勢評估表結合層級分析法建立層級結構，根據專家問卷的回饋，得到各層級中評估指標的權重，可針對目標橋梁作一沖刷潛勢評估，為橋梁是否需要安裝斷橋警示系統做一指標性之參考。
When the bridge failure events come, vehicles on the bridge may not get good vision or can’t exactly know the health of bridge forwardly, it is possible that people and vehicles will get great damage. The subject of study is to develop a reliable, low maintenance, cheap and effective warning system of bridge collapse, without the monitoring data and complicated theory, only judge from whether the event of bridge collapse happened or not, when it did, the warning system can exactly warn the people on the bridge to avoid the unnecessary damage. There are Water-Source and Circuit warning system respectively, the former uses the controller of water level in the water tank as detecting component, the water pipe connect the tank to the gap between the beams, when the beams have relative displacement, the cutting device which installs on lateral of beams will cut the pipe and make the water level descend, then the controller works to trigger the alarm, the latter uses the electric wire and relay as detecting component, then install and fix the wire at bridge unit like beams or piers, when it’s a large displacement between beams or piers, the wire breaks because of the pulling force, by the characteristic of relay, when the wire breaks, relay’s interior system will trigger the warning system. This paper has also take advantage of the evaluation table of scouring potential of bridge foundation from Ministry of Transportation and Communications, combining AHP and constructing the structure of hierarchy, regarding the feedback of expert questionaries, then get the weight of evaluation index in the hierarchy, so we can evaluate the scouring potential for the bridge and estimate whether the bridge installs the warning system or not. |
