對吊橋、斜張橋等鋼纜支撐橋梁而言，纜索為其重要的受力部分，橋體的受力狀態往往可由纜索索力的變化得知。因此，索力之監測為此類橋梁安全性確保的重要手段。而在監測索力的諸方法中，微振法由於具有非侵入性、操作簡便且能得到足夠精確之結果等優點，而被廣泛運用。為了減少監測儀器成本，本研究嘗試以電阻式應變計作為量測自然振動頻率之工具。本研究進行之相關實驗，包含鋼棒振動實驗、預力鋼絞線振動實驗，以及人行吊橋的現地量測實驗。實驗結果證實，若是作為電阻式應變計間接安裝平面之AB膠填充層與纜索之複雜表面保持足夠貼合，使纜索因振動產生之軸向應變的動態變化能確實為安裝於AB膠填充層上之電阻式應變計所量測，則電阻式應變計便能夠正確量測出纜索的自然振動頻率，進而評估纜索之現有索力。;For cable-supported bridge, like suspension bridge and cable-stayed bridge, cable is an important part to be taken force. The structure condition of the bridge usually can be known from the change of the cable force. So cable force monitoring is an important method to ensure the safety of the cable-supported bridge. In various ways to monitor the cable force, ambient vibration method is widely used since its advantage include non-invasive, easy to operate while getting good enough data. To reduce the cost of the monitoring, this research tried to use resistance strain gauge as the device to measure the natural frequency of the structure. The related experiments include the experiment of vibration of steel bar, the experiment of vibration of reinforced cable, local measurement experiment at a pedestrian suspension bridge. The experiment result confirmed that if the AB glue layer, as an indirect mounting plane for resistance strain gauge, remains sufficiently conformable to the complex surface of the cable, so the dynamic change of the axial strain of the cable caused by the vibration of the cable can be measured by the resistance strain gauge mounted on the AB glue layer, the resistance strain gauge can measure the natural frequency of the cable, and then evaluate the existing cable force of the cable.
