Dynamic Structural Analysis of Steel-Concrete Composite Highway Bridges Based on Monte Carlo Simulations

Resumo

The highway bridges are subjected to several random dynamic loadings of different intensities, among which the vehicles traffic is one of the most present. This type of loading generates displacements and stresses amplitudes that vary in intensity along the time, causing stress cycles on the bridge structural elements. When a structural element is subjected to these stress ranges, serious problems related to the fatigue phenomenon can occur. It is well known that an efficient analysis methodology to assess the fatigue service life caused by the road traffic is based on a dynamic analysis considering a coupled vehicle-pavement-bridge system. This way, this research work proposes an analysis methodology based on Monte Carlo simulations aiming to determine the fatigue service life of steel-concrete composite high way bridges. The main characteristics of the bridge and the vehicle are defined as random variables and the vehicle-pavement-bridge dynamic interaction effect is considered. Furthermore, the simulations are carried out considering two levels associated to the pavement degradation. The dynamic response of a typical simply supported steel-concrete composite highway bridge with straight axis and spanning 40 m is investigated. After that, the results calculated through the proposed analysis methodology, considering a large sample of the vehicle-pavement-bridge combinations, make it possible to assess which parameters of the vehicle-pavement-bridge system presented the most relevant influence on the fatigue service life of the investigated highway bridge.