Applications of ground penetrating radar (GPR) in bridge deck monitoring and assessment

Abstract

This paper presents the essence of two case studies by the authors on two major bridges in the UK. The first case study reports on the applications of GPR and associated work carried out on the Forth Road Bridge near Edinburgh, Scotland, with the main objective of identifying possible structural defects including damaged rebar and moisture ingress at specific locations of the bridge deck. The second case study focuses on a full assessment of the Pentagon Road Bridge, in Chatham, Kent England with particular emphasis on the identification of possible defects including structural cracks within the deck structure and establishing the layout of the upper and lower rebar positions throughout the bridge. These studies present interesting results in terms of locations of rebar and an accurate estimate of concrete cover condition as well as reporting on a remarkable similarity in the processed data concerning areas affected by ingress of moisture within the deck structures of the two bridges under investigation. It is believed that this paper will be of particular interest to bridge engineers and structural engineering practitioners with enthusiasm for adopting non-destructive testing methods such as GPR in the health monitoring and assessment of bridge structures. The observed similarities in the processed data between the two reported case studies present an interesting concept within the general context of the interpretation of GPR data, with the potential for use in many other forthcoming cases. The paper also reports on the adopted method for the GPR survey with emphasis on difficulties and challenges encountered during the actual survey. The presented results benefit from advanced processing and presentation techniques. (c) 2013 Elsevier B.V. All rights reserved.