無線監測橋梁淘刷系統之量測流程及數據分析初步研究

Preliminary Study on Measurement Quantification and Data Analysis of Wireless Monitoring in Bridge Scouring Depth System

林東儒(Dong-Ru Lin)

指導教授 ： 曾惠斌

國立臺灣大學/工學院/土木工程學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202102317

摘要

隨著極端降雨事件的增加，許多橋梁皆面臨嚴重的淘刷問題，但如今市面上多數淘刷深度監測方法及所用儀器，除了成本高昂外還有現地使用不易的問題，因此本研究使用加速度計MMF KB12VD以及Aduino Uno、Xbee無線傳輸模組等開源軟體，再搭配MATLAB軟體所組成的自製儀器進行微振量測試驗，在降低試驗成本的同時，也保障儀器的現地使用效率，藉此完成一套更高效且具備一定準確度的橋梁淘刷深度監測方法。
因此本研究會使用SAP2000有限元素軟體進行模擬，首先取得萬壽橋、一壽橋以及民權大橋的竣工圖，並依據橋梁現況進行建模，在將橋梁邊界條件、強度及土壤束制參數確定後，由軟體分析出橋梁的自然頻率與淘刷深度關係圖。
同時利用自製的無線感測儀器在橋面板上各位置進行水流方向頻率實測，在確定車流及水流量的變化對於測得頻率數值差異不大後，對各型式之鋼筋混凝土橋進行試驗，結果顯示在橋梁下游墩柱正上方的橋面板對應點周圍所量測的頻率數值和軟體模擬最接近，頻率差異比例在±1%內，並在對比真實淘刷深度(台北市政府工務局之實測值)後，發現模擬值和實測值差異在±5%內，故可由研究結果得出，此套為了自製儀器而找出的量測點位和數據處理方式對於萬壽橋、一壽橋以及民權大橋皆適用，因此以自製無線感測儀器監測橋梁淘刷深度具有一定可行性。

關鍵字

無線感測 ； 橋梁監測 ； 橋梁淘刷 ； 微振量測試驗 ； 有限元素分析

並列摘要

Due to extreme precipitation events are creasing. There are many serious scouring problems about the bridges. However, most of the scouring depth monitoring methods and instruments on the market are not easy to use and expensive. In order to reduce the cost of tests and improve the efficiency of the instrument, this study uses the self-made instrument that are composed of MMF KB12VD accelerometers and open source software such as Arduino Uno and Xbee wireless transmission module for micro-vibration measurement test. Finally, we use the instrument to build an accurate and more efficient monitoring method about bridge scouring depth.
Therefore, this research will build the model of bridge by finite element software SAP2000. Firstly, we obtain the completion drawings of Wanshou Bridge, Yishou Bridge and Minquan Bridge. After we build the models according to the bridge boundary conditions, strength and soil restraint parameters, the software analyzes the relationship between the natural frequency and the scouring depth of the bridge.
At the same time, the self-made wireless sensing instrument is used to measure the frequency of the water flow direction at each position on the bridge deck. After confirming the changes in traffic and water level are not significantly different from the measured frequency values, the study tests frequency values on various types of reinforced concrete bridges. The result show we will obtain the closest measured frequency values and software simulated frequency values when we install the wireless sensing instrument above the downstream column or around this point, and the frequency difference ratio between the two values is within ±1%. After comparing the actual scouring depth (Data come from Taipei City Government Public Works Department New Construction office), the difference between the simulated value and the measured value is within ±5%. Therefore it can be concluded from the research results that suitable measurement points and data processing methods are found by self-made instruments are applicable to Wanshou Bridge, Yishou Bridge and Minquan Bridge. In conclusion, the self-made wireless sensing instrument is feasible to monitor the depth of bridge.

並列關鍵字

wireless sensing ； bridge monitoring methods ； bridge scouring ； ambient vibration ； finite element analysis

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