Two analytical models developed to study the structural responseof curved prestressed concrete box girder bridges are presented. The first one consists of a filament beam model, with arbitrary longitudinal and sectional geometry. Concrete and steel are assumed to be subjected to a uniaxial stress state. Material nonlinearities such as cracking of concrete, yielding of steel, and so forth are taken into account. Flexural and torsional behaviors are considered uncoupled. Time-dependent effects due to load history, creep, shrinkage, andaging of concrete and relaxation of prestressing steel are also included. In the second approach, a box-beam straight element of non-deformable cross section composed of concrete panels with steel layersis used to model the bridge. Concrete is assumed to be subjected toa biaxial stress state. Material nonlinearities are also considered. Longitudinal and transverse prestressing can be included. Couplingbetween flexural, torsional, and shear response of the cross section is considered. A curved prestressed box girder bridge constructed in spain is analyzed by the two models presented under different loading conditions. Short-term analyses with increasing overload to failure demonstrate the applicability of the uncoupled model when either bending or torsion is dominant, whereas for other cases coupling is necessary to accurately predict the structural response. A time-dependent analysis under permanent loads is made, followed by a long-term overload analysis showing the effects of time in the structural response. The influence of transverse prestressing on the structuralbehavior is also studied. This paper appears in transportation research record no. 1180, bridge design and testing.
Abstract