Evaluation of strengthening through laboratory testing of FRP rehabilitated bridge decks after in-service loading

This paper provides details of an investigation into strengthening efficiency of FRP rehabilitated bridge deck slabs through tests conducted on slab sections cut from a bridge just prior to demolition. Thus the deck sections (one unstrengthened, and two strengthened using FRP composites) were subjected to routine traffic prior to removal and testing. A systems identification technique was used to match the response of the finite element model with that of the test specimen obtained through forced vibration based dynamic modal tests. Available analytical models and design guidelines were used to predict the response and capacity of such field representative specimens. The test results validated the efficacy of FRP strengthening as a means of life extension and demonstrate the feasibility of rehabilitation for two different modes of intended response. The predictions were found to closely match the actual response of the test specimens. The use of infrared (IR) thermography as a tool for damage/defect detection as well as in monitoring the progression of damage was also demonstrated. Finally, the equivalent capacity of the bridge deck slabs was computed based on a local–global modeling approach.