模態分析法檢測鋼筋混凝土橋面版之初步研究

Study of Inspection of RC Bridge Decks Using Modal Analysis Method

梁明德 ； 黃然 ； 黃怡文

《中華民國振動與噪音工程學會論文集》 1995 (1995/06) Pp. 123-130

https://doi.org/10.30028/CSSVANNUAL.199506.0123

摘要

安全性為橋梁設計與施工的主要考量，如何藉由快速、方便且可靠的檢測方法偵測結構體的完整性，協助設計者與施工者對於橋梁新建工程品質的控制及完工後的維護是工程界重要的研究課程。本研究的主要目的是利用模態分析法對使用不同混凝土水灰比及不同鋼筋號數的鋼筋混凝土版，以兩側簡支撐形式模擬橋面版進行非破壞性檢測之可行性分析。藉由振動頻率、阻尼因素及模態的變化評估鋼筋混凝土橋面結構物的完整性。並由基本假設推導版的控制方程式，以有限元素法計算版在簡支撐下的頻率、阻尼、模態形狀。實驗變數包括水灰比大小、鋼筋尺寸、缺陷位置及裂縫數目等。試驗結果顯示，振動頻率隨版的密度的增加而遞增，但卻隨著鋼筋號數的增大而縮小。至於鋼筋在長方向被抽出的混凝土版，由於版的慣性矩減小，質量也變小，所以量測得到的頻率值高於內含有鋼筋混凝土版。

關鍵字

頻率 ； 阻尼 ； 模態形狀

並列摘要

Safety is the major consideration in bridge design and construction. It is a necessary measure to determine the integrity of the bridges using reliable testing methods for quality control and maintenance checkup. The objective of this research is nondestructively evaluate the defects of reinforced concrete decks using modal analysis method. The boundary conditions of the plates are simply supported at two-side .A total of seventeen plates with various defects were tested in the laboratory. Vibration frequencys, damping factors, and mode shape were recorded and analyzed to evaluate the integrity of each plate. Testing variables include boundary conditions, the types of the defects, and the locations of the defects. In addition, analytical solutions for each plate will be obtained and compared using finite element method. The test results can be drawn out as follows: l. The frequency of vibration increases when the density of plate is increased while the vibration frequency decreases when the steel number increase.2.If the steel in the long direction in the reinforced plate is pulled out, then the moment of intera of plate and mass are decreased. Thus, the measurement frequency is higher than the reinforced concrete plate ones.

並列關鍵字

frequency ； damping ； mode shape