Flexural behavior of aged prestressed concrete girders strengthened with various FRP systems

摘要

Many prestressed concrete bridges are in need of upgrading in order to increase their posted capacities. Departments of transportation across the country have been faced with large financial burdens on the maintenance budget, negative psychological effects on highway users, long traffic delays during maintenance, potential safety hazards, and reduced service life as a result of the deficiencies. In response to considerable consultation with the North Carolina Department of Transportation (NCDOT), a research project with practical goals was initiated to evaluate the cost-effectiveness and value engineering of Carbon Fiber Reinforced Polymer (CFRP) repair and strengthening systems for prestressed concrete bridge girders. This paper presents the first phase of the research program, involving the testing under static loading conditions of eight prestressed concrete bridge girders, six strengthened with various CFRP systems. Results show that the ultimate capacity of prestressed concrete bridge girders can be increased by as much as 73 percent using CFRP without sacrificing the ductility of the original member. Transverse CFRP U-wrap reinforcements are recommended along the length of the girder to control debonding type failures. The second phase of the research will examine the fatigue behavior of the strengthened girders, and provide analysis under service loading conditions.