ABSTRACT
Many of the nation’s steel highway bridges have been classified as structurally deficient. To ensure their safe and reliable operation an accurate and cost effective measurement technology is required. This paper examines the applicability of an alternative ultrasonic measurement technique. Laboratory testing on mild steel structural members verifies linearity of the acoustic measurement technique relative to surface strain as measured by a strain gauge (r2 = 0.9984). Field tests conducted on three highway bridges support the results obtained during laboratory testing. Good correlation was achieved between surface stress and acoustic measurements for the three bridges examined in this study. Furthermore, measurement speed and resolution proved to be adequate for monitoring bridge loads on rough, pitted, and painted surfaces. The ultrasonic technique examined in this study is comparable in performance to the traditional strain gauge measurement technology, and offers a portable, cost effective method for monitoring bridge loads and other types of structural loading.
