Acoustic Emission Testing of Repaired Prestressed Concrete Bridge Girders

Abstract

Acoustic emission (AE) monitoring has proven to be a useful nondestructive testing tool in ordinary reinforced concrete beams. Over the past decade, however, the technique has been used to test other concrete structures to provide information on its usefulness. It has been seen that acoustic emission monitoring can be used on in-service bridges to obtain knowledge regarding the structural integrity of individual components of the structure. In this thesis, acoustic emission testing was used to examine the structural integrity of four prestressed girders in an elevated portion of the I-565 highway in Huntsville, Alabama. The testing was performed to assess the evaluation criteria used for in-situ testing and to determine the effectiveness of a fiber-reinforced-polymer (FRP) repair that was applied after substantial cracking occurred in the girder ends near the continuity diaphragms. The evaluation methods that were implemented were the NDIS-2421 evaluation criterion, the Signal Strength Moment (SSM) Ratio evaluation, and the Peak Cumulative Signal Strength (CSS) Ratio analysis. It was concluded that although the testing procedure provided results efficiently, the evaluation criteria need to be adjusted for the testing of in-service prestressed concrete bridge girders. It was also determined that the FRP repair did have an effect on the AE data, but a direct correlation between the two was not established due to the complexity of the testing.