Issued as the Final Report on an Investigation of Field-Made Joints in Prestressed Reinforced Concrete Highway Bridge Girders; Project IHR-303, Illinois Cooperative Highway and Transportation Research Program

摘要

Tests of two prestressed concrete composite bridge girders which were continuousover two spans are reported. Both were I-section girders with cast-inplacedecks, and had spans of about 37 ft (11 m), and were approximately 1/3 scalemodels of structures spanning 125 ft (38 m). Each girder was constructed fromthree segments which were joined end-to-end by cast-in-place concrete splices.Modell was post-tensioned after erection of the girders and casting ofthe deck and splice concrete. The two end segments, each supported on the finalabutments and on temporary supports located about 1/3 of the span from the centralpier, were pretensioned for their dead loads plus the deck concrete. The centralsegment, which was supported on the central pier of the structure plus the twotemporary supports was precast reinforced concrete, plus a small amount of pretensioned reinforcement. Model 2 was externally similar, but was not post-tensioned.The segments were pretensioned for the final moments, and were joined by splicingreinforcing bars which extended into the splice region.Both structures were subjected to a series of loadings to the service load,design ultimate, and high over-load levels. Both had capacities which weresignificantly higher than the design ultimate values. The capacities weregenerally predictable on the basis of flexural strength calculations, and sheardid not cause major problems. Joint details in Model l lead to difficulties intwo tests, and this aspect of the design is discussed in detail.