模態分析法評估混凝土短柱完整性之研究

An Evaluation on the Integrity of Short Columns Using Modal Analysis Method

梁明德(M. T. Liang) ； 黃然(R. Huang) ； 葉啓章(C. C. Yeh)

《中華民國振動與噪音工程學會論文集》 1994 (1994/06) Pp. 27-34

https://doi.org/10.30028/CSSVANNUAL.199406.0027

摘要

本文旨在說明應用非破壞性模態分析法評估混凝土短柱之完整性，採用雙頻道訊號分析儀(dual channel signal analysis)配合衝擊鎚(impact hammer)與加速計(accelerometer)等實驗設備及PCMODAL分析軟體進行實驗研究，以二種水灰比0.45及0.55澆灌長10cm寬10cm高30cm之泥凝土方形柱。以完整的及有裂縫缺陷的方形柱，在彈性基礎支撐條件下，利用模態分析法得到頻率曲線及限尼因數以評估方形柱的完整性。研究結果指出龜裂深度明顯影響自然振頻與頻率曲線，當龜裂愈深，自然振頻下降愈多，混凝土結構物強度愈低，再者，當開裂深度為1cm時，龜裂位置影響模態及頻率曲線並不明顯，但若龜裂深度大於3cm時，龜裂位置對模態及頻率曲線影響非常顯著，由此証明模態分析法可做為評估混凝土短柱的完整性。

並列摘要

This aim of the study was to investigate the integrity of short columns using modal analysis technique. The frequency, damping factors, and model shapes were recorded. Testing variables included boundary conditions, depths of cracks and the location of the cracks. Test results indicate that the frequency and the mode shape of vibration may provide information of internal condition of short columns. The depth of the crack has significantly affected the natural frequencies. The deeper the crack is, the more the frequencies is reduced. In addition, the position of crack has strong influence on the frequency curve as long as the crack is deep enough.