Time-Dependent Deformation Behavior of Prestressed High Performance Concrete Bridge Beams

Twelve long span high performance concrete Texas Type U54 bridge beams prestressed with 15.2 mm -diameter low relaxation strands and having design concrete strengths of up to 90.3 MPa were instrumented and monitored in the field from transfer of the prestressing strands, strain distributions at midspan, and internal beam temperatures were monitored during that time period. Companion tests were performed to determine the material properties of the beam concrete.

The measured time-dependent camber, deflection, and prestress losses at midspan were compared to results from several analytical techniques. Based on measured properties and an analytical time-step procedure, multiplier equations were developed to predict camber and deflection for the beams in this study.