Avaliação de viga de concreto pré-moldado para pontes rodoviárias com vão entre 15 e 35 metros

Abstract

One of the most used methods worldwide for the construction of bridges and viaducts with spans of up to 40 m is what contains prestressed precast beams and concrete slabs on site. In Brazil, it is common to use precast concrete beams simply supported forming independent isostatic spans, putting joints on the supports. The present work aims to determine the allowable range of spans for a prestressed concrete beam, with a cross-section type I, that can be used in a road bridge deck. For this report, it was considered a class 45 bridge with 10 m of width and span varying from 15 m to 35 m. Different deck options were adopted, with interaxis varying between 0.50 m and 1.50 m. Isotropic concrete C40 was considered for beams and orthotropic concrete C40 for the slab, so the entire longitudinal flexure stress of the deck would be resisted by the beams. For the active reinforcement, chordae with 12.7 mm diameter and CP190RB steel were considered in 12 different arrangements. The maximum shear forces and bending moments were compared to the maximum allowed, through an analysis in the Ultimate Limit State and in the Serviceability Limit State. The results were presented in graphs that allow the identification of the limits of use of the beam considered, being the maximum allowable span of 30.7 m.