Modern NDT Systems for Structural Integrity Examination of Concrete Bridge Structures

Abstract

The paper presents an overview of modern Non-Destructive Testing methods that can be applied for concrete integrity evaluation, with particular attention paid to bridges. Assessment of “in-situ” quality of concrete and its integrity is primarily concerned with the current adequacy of the existing structures and their future performance. Routine maintenance needs of concrete structures are now well established and increasingly utilize “in-situ” NDT-testing to assist lifetime predictions. Such approach allows evaluating the basic concrete composite properties and makes possible to answer several questions, which seem to be crucial for engineering practice. Among other things, “Impact-Echo” and “Impulse Response” seem to be one of more promising diagnostic techniques for structural integrity testing of concrete structures. The general principles of these advanced testing methods are discussed. Among other things, it has been shown that Impulse-Response can be used for fast screening of large areas of concrete structures with the purpose to control their structural integrity and to determine local areas with possible flaws for subsequent detailed analysis, e.g. by the impact-echo, ultrasound shear waves or by invasive inspection with drilled cores. Main evaluation parameters have been discussed and general recommendations for proper interpretation of obtained results were proposed. Practical applications of these methods have been discussed as well.