FINITE-ELEMENT MODELING OF CONTINUOUS POSTTENSIONED VOIDED SLAB BRIDGES

Two quarter-scale, continuous, longitudinally and transversely postten sioned, two-lane, voided-slab-bridge models-one straight and the other curved in plan-were tested to determine the service-load response und er symmetric placement of simulated truck loading according to the Ame rican Association of State Highway and Transportation Officials, Each model was 2.0 m (6 ft 7 in.) wide, with two equal spans of 8.0 m (26.2 7 ft) measured along the centerline. The curved model subtended an are of 40 degrees on a radius of curvature of 22.92 m (75.2 ft). The void ed slab bridge was idealized as an orthotropic plate and its elastic r esponse determined from a two-dimensional finite element analysis usin g isoparametric, quadrilateral shell elements. The commercially availa ble computer program ANSYS was used to conduct the analysis. This pape r presents comparisons of predictions from the finite element analysis with test results for deflections, reactions, and stresses. The resul ts show reasonable agreement for the straight model but not for the cu rved model, where the correlation is poorer. This suggests that the eq uivalent orthotropic plate parameters proposed in the literature need to be modified for applications involving curved structures.