Fuzzy-based decision-making process for assessing in-service AASHTO prestressed concrete bridge girders: Framework development and computer application

There are about 200 bridges in Nova Scotia that were constructed using the American Association of State Highway and Transportation Officials (AASHTO) prestressed concrete girders in the 1970s. Condition assessment of some of these bridges indicates severe deterioration due to corrosion and alkali silica reactivity (ASR). As these bridges are approaching end of life, decisions need to be made to repair deficiencies or replace severely deteriorated bridge components. In this research, a novel framework for decision-making will be developed and programed in a computer application in partnership with Nova Scotia Department of Public Works (NS-DPW) to aid inspectors in assessing the condition of bridges with AASHTO prestressed girders. Using this tool, visual observations about the girder condition will be quantified into a condition index through a systematic procedure using fuzzy logic. The decision to repair, replace, refine the structural analysis, obtain non-destructive tests, or take no action will be made given the value of the condition index and the consequence of girder failure. The consequence of girder failure will be quantified based on system and element risks as determined using the Canadian Highway Bridge Design Code (CHBDC 2019). The tool will be developed in the following phases: capacity prediction of deteriorated prestressed AASHTO girders by testing and nonlinear finite element simulation of a decommissioned girder (Phase 1), fuzzy logic framework development for analyzing inspection data (Phase 2), and computer programming and technology transfer by applying the framework to assess in-service bridges (Phase 3). Benefits to Canada include optimized cost allocation for bridge construction projects (economic) and reduced greenhouse gas emissions by promoting repair as opposed to replacements which typically yields reduced carbon footprint (environmental).