This report is designed to provide information to guide inspectors of wood highway structures in the use of stress wave inspection technology. It explains the methods and instruments used to measure the velocity of stress waves (sound) in wood. The characteristic behavior of sound waves in wood of various species, moisture content, preservative treatment and infection by wood destroying organisms is described. The important effects of the anatomy of wood and the orientation of grain and annual rings to the wave path are discussed to aid in the interpretation of measurements.
Characteristics of the instrumentation essential to its calibration are explained and instruction is provided in the appropriate use of these tools.
This report has been written to serve as a manual for "on site" stress wave inspection of the kind of wood structures found in highway systems. It is a compendium of experience in the field inspection of many wood buildings and highway bridges.
Original research conducted to fill in voids in the published studies is described in the Appendices.