Predicted and Measured Performance of Prestressed Concrete Bridges

Abstract

Testing results of six existing prestressed concrete bridges are used to evaluate analytical methodologies. These bridges cover different span lengths, number of lanes, and skew angles. Strains, load distribution factors, and ratings predicted by finite-element analyses and AASHTO code specifications are compared with those from measurements. The comparison reveals a significant difference between the analytical and test results due to the effects of many field factors. Factors that exist in reality but whose effects on bridge performance cannot easily be quantified are defined as field factors. Due to these field factors, existing bridges are different from idealized calculation models and are thus defined as field bridges. To examine this difference and to quantify their effects, some field factors are modeled in a more refined finite-element analysis. It is found that the field factors have a larger effect on the maximum strain than on the load distribution factor. Parametric studies of the effects of diaphragms, bearing stiffness, and skew angles on the load distribution and maximum strain are conducted.