以波形疊加技術量測鋼筋保護層厚度

Determining the Concrete Cover by Overlapping Waveform Method

劉宗豪(Tzunghao Liou) ； 胡盟宗(Meng-Tzung Hu) ； 謝世傑(Shi-Jie Shieh)

《中國土木水利工程學刊》 23卷3期 (2011/09) Pp. 269-274

https://doi.org/10.6652/JoCICHE.201109_23(3).0003

摘要

本研究目的在探討可感測敲擊時間原點之敲擊器以及波形疊加技術應用在較深層鋼筋保護層厚度量測之可行性。經實驗證實，應用可感測敲擊時間原點之敲擊器，由於其電壓波形模式極為簡單，可直接得到敲擊時間原點，更有利於電腦自動判讀。應用在深度超過100 mm鋼筋保護層厚度量測時，由於檢測配置距離較遠以及鋼筋折反射面積有限，故常有應力波能量不足而導致接收訊號微弱而無法判讀波到時間。本研究配合波形疊加技術來克服起始擾動振幅太小之問題，若採用直徑3 mm鋼珠為敲擊源，波形疊加約5次即可得到穩定結果。

關鍵字

鋼筋保護層 ； 應力波 ； 波形疊加

並列摘要

The objective of this paper is to investigate the concrete cover measurement by a simple impact device and overlapping waveform technique. Experimental results show that the pattern of voltage output of impact device is very easy to identify and the initial time of impact can be measured directly without placing additional receiver. The impact device enables the overlapping waveform technique to analyze waveform automatically by computer. When the concrete cover, over than 100 mm, is measured, long distance between impactor and receiver is required; therefore, the amplitude of surface displacement caused by refracted P-wave from limited reinforcement surface is so weak that it is hard to interpret the exact arrival time of stress wave. In order to overcome the difficulties for measuring the concrete cover, superposed waveform method was utilized to enhance the initial disturbance of waveform. In this paper, overlap of five displacement waveforms can provide a stable and satisfied result when 3 mm diameter impactor is used.

並列關鍵字

concrete cover ； stress wave ； overlapping waveform