Finite Element Modeling of Continuous Posttensioned Voided Slab Bridges

Abstract

Two quarter‐scale, continuous, longitudinally and transversely posttensioned, two‐lane, voided‐slab‐bridge models—one straight and the other curved in plan—were tested to determine the service‐load response under symmetric placement of simulated truck loading according to the American 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 (26.27 ft) measured along the centerline. The curved model subtended an arc of 40° on a radius of curvature of 22.92 m (75.2 ft). The voided slab bridge was idealized as an orthotropic plate and its elastic response determined from a two‐dimensional finite element analysis using isoparametric, quadrilateral shell elements. The commercially available computer program ANSYS was used to conduct the analysis. This paper presents comparisons of predictions from the finite element analysis with test results for deflections, reactions, and stresses. The results show reasonable agreement for the straight model but not for the curved model, where the correlation is poorer. This suggests that the equivalent orthotropic plate parameters proposed in the literature need to be modified for applications involving curved structures.