橋梁頻率間接量測法之實驗改進與研究

Experimental Study and Improvement on Indirect Method for Measuring the Bridge Frequencies

吳冠甫(Kuang-Fu Wu)

指導教授 ： 楊永斌

國立臺灣大學/工學院/土木工程學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.00815

摘要

橋梁系統結構的整體性檢測，最常見的方式是以橋梁頻率作為參考依據。目前而言，量測橋梁頻率的方式共有兩種：直接量測法與間接量測法。直接量測法主要利用直接安裝在橋梁主體上的感應器，對橋梁作直接的振動量測，以此得出橋梁的動態特性如頻率和振態等；相對地，間接量測法是指利用安裝有感應器之移動車輛通過橋梁，間接從車體動力反應中擷取出橋梁振動頻率。直接量測法發展歷史悠久，技術成熟，通過合理的佈置量測點，即可以得到橋梁各個模態的頻率、振態形狀。2004年起，由楊永斌教授團隊首創的間接量測法，已證實在理論分析與現地試驗中能量測得到橋梁的頻率。
本研究的目的為利用實際試驗的方式，來比較不同形式的量測車於間接量測法的試驗結果，藉由更換輪胎種類、試驗車重量、行進速度，進行試驗參數比較分析。本研究的成果，驗證了試驗車體本身的動力特性，對間接量測法能否成功具有關鍵性的角色。本文最後將綜實驗室和現場實驗所得結論，特別是有關量測車的設計，以供未來量測車設計、現地量測試驗、以及進行後續橋梁間接量測研究之參考。

關鍵字

橋梁 ； 頻率 ； 間接量測法 ； 現地試驗 ； 試驗拖車

並列摘要

Bridge frequency is the key parameter commonly used for detecting the integrity of bridges. Nowadays, two approaches can be used for measuring the bridge frequencies, i.e., the direct approach and indirect approach. With the direct approach, the dynamic properties of the bridge, such as frequencies and mode shapers, are obtained from the bridge response measured by the vibration sensors directly mounted on the bridge. In contrast, using the indirect approach, the dynamic properties of the bridge are extracted indirectly from the response of an instrumented test vehicle recorded during its passage over the bridge. The direct approach has been developed for many decades and is considered a mature technique. With proper arrangement of vibration sensors on a bridge, the frequencies and mode shapes of the bridge can be measured with no difficulty. The indirect approach was firstly proposed in 2004 by Yang and co-workers. It has been demonstrated to be capable of extracting the bridge frequencies both theoretically and experimentally.
The purpose of this thesis is to study the effect of various test vehicles on the measurement results via the on-site test. The parameters considered include the type of tires, weight and moving speed of the test car, and so on. Based the test results achieved, it is concluded that the dynamic properties of the test vehicle are crucial to the successful extraction of bridge frequencies using the indirect approach. At the end, some conclusions based on the lab and field tests will be drawn, including particularly the basic rules for design of test vehicles. All these should prove useful to the future design of test vehicles, field tests, and related studies on the indirect approach.

並列關鍵字

bridge ； frequency ； indirect measurement ； on-site test ； test vehicle

參考文獻

吳峰賓 (2010)，「考慮路面粗糙度與車輛非線性勁度於橋頻間接量測法之模擬分析」，國立台灣大學土木研究所碩士論文，楊永斌教授指導。

李育謙 (2011)，「濾波技巧於橋梁頻率間接量測法之應用」，國立台灣大學土木研究所碩士論文，楊永斌教授指導。

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