Análise sísmica de pontes em território brasileiro - estudo de caso de uma ponte estaiada

Abstract

Brazil is usually considered a low seismic risk country, so designers, in general, ignore the participation of this action in the structural design of buildings and bridges. However, the mapping of the Brazilian seismic risk shows that in reality there are areas of the national territory where the risk of seismic action is real. There is a large gap in the Brazilian standard regarding the seismic action of bridges. In fact, there is only one Brazilian standard that addresses the issue of seismic design, and only restricted to buildings, the NBR15421 dated 2006. The available methodologies for measuring seismic forces are presented, namely the methods: static; modal; linear dynamics; non-linear dynamics, as well as the measurement and verification of performance based design, the latter not mentioned by the Brazilian standard NBR15421 (2006), neither when dealing with bridge structures. The seismic analysis proposed by EN1998-2, dated 2005, was developed for a real bridge for different seismic situations and its seismic resistance was verified for each case in relation to the executed project. Based on the results presented, the structural performance was evaluated and the need to consider the seismic action in part of the national territory was verified, with the need for confinement and adequate detailing of the reinforced concrete.