Avaliação do comportamento de pontes com tabuleiros de dupla ação mista submetidas ao tráfego de trens de alta velocidade

Abstract

This study addresses the static and dynamic behavior of a high-speed rail (HSR) bridge, as well as its verification of the safety criteria. The bridge under study, called “La Scarpe”, is part of the French HSR network (TGV Nord) and is composed of steel-concrete deck structured in a continuous slab with nine spans, totalizing 333 m in length. This study assesses a modification in the superstructure of this bridge by adding a lower concrete slab in the region of negative bending moment between the inflection points, transforming it into a structure known as double composite action. Thus, a methodology was developed to statically and dynamically evaluate HSR bridges composed of double composite action decks. Subsequently, numerical models were developed, both for the original deck and the modified one, through the Finite Element Method (FEM) using the ANSYS v.12 software. The modeling of the original deck was validated through comparisons between theoretical and experimental results for the “La Scarpe” bridge available in the literature. Thus, the results obtained in the numerical modeling for the original and modified decks were compared in order to identify the advantages and disadvantages resulting from the use of composite steel-concrete decks with double composite action. The addition of the lower slab resulted in a increase of the modes of bending and, especially, torsion modes, resulting in reduction of the levels of displacement and acceleration of the structure when loaded by the passage of high speed trains. Finally, the safety of the modified deck was verified according to requirements of the European standard. The double composite action deck proved to be a good solution for bridges submitted to the transition of high speed trains, especially for continuous composite structures, with loads that provide negative bending moments on the support and twist of the deck, and may even reduce the cost of the steel used in the structure.