Análise paramétrica da distribuição de esforços internos devidos às cargas móveis em tabuleiros alargados de pontes esconsas em viga

Abstract

The road modal participates significantly in the Brazilian transport matrix. Currently, Brazil is witnessing an increase in the demand for road traffic from larger, heavier and more numerous vehicles, as well as adjustments in the requirements necessary for the design of road bridges, present in the relevant standards, which has led to a large part of the old bridges not meet the new project specifications, requiring interventions, including the widening of decks. Such interventions cause the bridges to present a new distribution of internal forces, this distribution being more complex in the case of skewed bridges, due to their structural configuration, since the elements of these structures are arranged in such a way that there is not a right angle between the axis of the bridge and the transposed obstacle, behavior commonly defined by a skew angle. However, the widening of existing skewed bridges is still little investigated in the scientific community. In this sense, the objective of this work is to evaluate the distribution of internal forces (due to moving loads) in widened skewed girder bridges considering three different parameters: number of girders, compressive strength of the concrete in the widening regions and skew angle. For this, analytical and numerical models were developed, via finite element method (FEM), in order to enable the analysis of the distribution of internal forces in the widened structure, through the distribution factors of bending moment (FDMFs) and shear force (FDFCs). As a result, it was observed that there was a progressive transfer of absorption of bending moments from the old girders to the widening girders with an increase in the compressive strength of the concrete in the widened sections. Regarding the number of girders in the models, the increase in the compressive strength of the widening sections reduced the percentage difference, in modulus, between the old girders and the widening girders, while the increase in skewness directed the bending moments towards the initial girders. When analyzing the influence of skewness, in general, there was a similar behavior between skew angles from 0° to 30°, while the models with skewness of 60° differed from the others, so that the increase in the skew angle directed the absorption of bending moments for the external girders. Finally, the largest percentage differences were obtained through the FEM, followed by the analytical methods.