Avaliação de viga de concreto pré-moldado para tabuleiro de ponte rodoviária

Abstract

Bridge decks made of slab supported by precast beams are widely used because of its quick execution and be economically very competitive for spans of up to 50m. This study aims to determine the allowable range spans of a precast concrete beam section type I prestressed for use in highway bridge deck. Modeling and analysis of the problem, it was used the Civil Midas 2011 software. For the study was taken as an example a class 45 bridge with 10m in width and length ranging from 5 to 25m. The inter-axis distance between the I section beams varied from its minimum value equal to 0.50 m, case juxtaposed beams, up to a maximum of 1.50 m. The material of the beams considered was a isotropic concrete C40 for slabs and a orthotropic concrete C40 for beams, so any longitudinal bending stress tray is fully resisted by the beams. After defining the geometry, materials, boundary conditions and dead and live loads, the maximum shear forces and bending moments that which the beams are subject are calculated. The maximum values were compared to the maximum permitted by norme, through an analysis on the Ultimate Limit State and the Service Limite State. Active prestressing reinforcement consists of chordae of 12.7mm and steel CP190RB. It was considered eight kinds of chordae arrangements in the bottom of the beam bead. The results are presented in graphs that help the draftsman or manufacturer to identify the limits of use of the produced beam. It was verified that the I-beam analyzed may be used to limit the range of 22m