Grading and in-situ evaluation of wooden structural members have traditionally been conducted using visual inspection. Such inspection only provides qualitative information about the condition of the member and is not always reliable. To obtain quantitative information about the strength and stiffness properties of in-situ members, it is necessary to use nondestructive testing techniques. The ultrasonic technique has proved to be a useful technique for detecting defects and predicting stiffness of wooden structural members. The technique in the past has relied solely on velocity measurements in the time domain. To increase the sensitivity of the technique, this paper proposes to use signal amplitude measurements in time and frequency domanis. Various parameters to quantify the signal amplitude information (e. g., area under the power spectrum) are discussed. To facilitate rapid data acquisition and processing in the field, a hand held Timber Properties Monitoring Device (TPMD) has been developed. The device was used for condition assessment of wooden members of a historic covered timber bridge located in West Virginia, U. S. A. A brief description of the device and the summary results of the field testing are presented.
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