SONIC NDE OF BRIDGES AND OTHER CONCRETE STRUCTURES

This paper presents recent innovations for sonic and ultrasonic scanning of concrete bridges and structures. Recent technical advances in instrumentation systems by the author's firm allow, for the first time, the potential for rapid scanning of structural concrete with ultrasonic and sonic methods. This recently developed instrumentation provides for practically continuous nondestructive testing with PC-based data acquisition and software analysis. Test data are presented to illustrate the applications of the scanner to traditional point-by-point Ultrasonic Pulse Velocity and Impact Echo methods. The paper also presents an introduction to a technology recently applied to nondestructive evaluation of concrete structures, especially slabs, tunnels, massive concrete structures, and other installations where information on thick concrete or on concrete and the subsurface behind the concrete is required. The technology, Spectral Analysis of Surface Waves, allows nondestructive determination of the shear wave velocities of the various components of a layered system while testing from only one surface. Included is an overview of the method and the principles behind it, as well as some case-history examples.