Application of FRP in development of high performance continuity connections

To improve structural efficiency and enhance maintenance, cast-in-place concrete diaphragm and deck is used to provide partial or full continuity in Simple-Span Precast Prestressed Bridge Girders Made Continuous. However, existing continuity connections also have their own structural, construction, and maintenance shortcomings. Discussions of existing continuity connection, field investigation, and development of a new continuity connection using Carbon Fiber Reinforced Polymer (CFRP) are the subjects of this paper. The proposed design will address existing shortcomings while further enhancing structural effectiveness. At the column bents, under gravity load the deck-girder system is subjected to negative moment. Therefore, to provide continuity, CFRP reinforcement is attached to the top of the girders over the cast in place diaphragm. The negative moment over the supports caused by the deck weight balances the positive restraint moment caused by creep in the prestressed girders. Thus, while increasing structural efficiency the proposed design eliminates positive moment cracking. Additionally, there is no need for positive moment reinforcement in the diaphragm under gravity loads, thus, reducing reinforcement congestion and facilitating construction. Summary of analytical and experimental results are presented, which support the viability of the proposed connection in enhancing structural performance of multi-span bridges.