Development of camber multipliers for precast prestressed box girders

This thesis addresses the difference between design camber predictions using the Precast/Prestressed Concrete Institute (PCI) methodology and constructed camber predictions for precast prestressed box girders. Existing bridges constructed with box girders with a range of spans, depths, sections, and fabricators are field measured for camber. A statistical analysis of the field data is preformed to compare design versus constructed camber. Revised multipliers for design are calculated based on statistical distributions of the field data. Additionally, girders are selected from various bridges and analyzed theoretically for camber using the Tadros equation. The girders are also analyzed for consideration of the two-stage pour sequence that is common in the construction of box girders in Colorado. The field data cambers and theoretical cambers are compared and analyzed. Recommended multipliers and high and low multipliers are found. The multipliers are found to be lower than the PCI and Martin multipliers and are recommended to be 1.65 for the prestress camber and 1.70 for the self-weight deflection.