Restraint Moments in Precast/Prestressed Concrete Continuous Bridges 40 Zhongguo (John) Ma Ph.D., S.E. Research Assistant Professor Department of Civil Engineering University of Nebraska-Lincoln Omaha, Nebraska Xiaoming Huo, Ph.D., P.E. Assistant Professor Department of Civil Engineering Tenn essee Technological University Cookevill e, Tennessee Maher K. Tadros, Ph.D., P.E. Cheryl Prewett Professor Department of Civil En gineering University of Nebraska-Lincoln Omaha, Nebraska Mantu Baishya, Ph.D., S.E. Research Assistant Professor Department of Civi l Engineering University of Nebraska-Lincoln Omaha, Nebraska To eliminate deck joints and shoulder piers , co ntinuous span (jointless) brid ges are becoming an attractive option. Different continuity methods and construction sequences have different time- dependent effects on the behavior of the bridge system. These effects are illustrated in this paper. To achieve a favorable performance of bridges made continuous for deck loads, recommendations for achieving continu ity and for desirable construction sequence are presented. A new continuity detail using high strength threaded rods is proposed. Based on a cost comparison with currently available continuity methods and a full-scale NU7700 /-beam experiment, this continuity detail is shown to eliminate the potential for bottom concrete creep restraint cracking at pier lo ca tions and to increase the span capacity by as much as 20 percent. B ridge engineers are continually being challenged to design bridges with longer s pan s. Thi s trend is partly due to safety require ment s that dictate the elimination of piers adjacent to roadway shoulders in over- pass bridges and the need to reduce the number of piers in water crossings. The desire to eliminate deck joints and their potential for long-term maintenance costs ha s also contributed to the need for developing techniques to create continuity in bridge superstructures. More factors need to be considered in the design and construction of jointless bridge s as compared to simply supported bridge s. One such factor is de sign for time- dependent restraint positive moment at pier locations. A PCI JOURNAL