Improved assessment of mass concrete dams using acoustic travel time tomography. Part I — theory

Abstract

This is the first part of an investigation on improved assessment of mass concrete dams using Acoustic Travel Time Tomography (ATTT). It presents the concept and basic science for ATTT. ATTT combines aspects of ultrasonic measurements previously used for material characterization, ultrasonic methods applied to test concrete and features of methods used in shallow seismic surveys. This science/technology is integrated into a system that records travel time data and applies tomography software. The resulting tomographs have the potential to provide cross-sectional images of the structure that can be used to locate cracks, identify regions of structural damage, and other anomalies deep inside a massive concrete structure. Results from initial laboratory and field studies obtained with a system that embodies the approach presented in this paper and which provides proof-of-concept data, are presented in a companion paper (Kepler WF, Bond LJ, Frangopol DM. Improved assessment of mass concrete dams using acoustic travel time tomography. Part II — applications. Constr Build Mater, 2000; vol. 14, No. 3, pp. 147–156).