Security aspects of vertical actions on bridge structure: Comparison of earthquake and vehicle induced dynamical forces

Abstract

Purpose

The purpose of this paper is to investigate internal forces in bridges induced by moving vehicles and compare them to earthquake loading.

Design/methodology/approach

Dynamic analysis of bridges is performed for moving support actions, for spectral method with Eurocode 8 parameters and for moving vehicle influence. Results from all three methods have been compared on two examples and conclusions have been made. Moving vehicle analysis could be based on the moving force and on the moving mass approach where the later one requires rather accurate knowledge of structural accelerations. It has been shown that the classical Newmark formulation produces accelerations of low accuracy and a novel impulse acceleration method has been devised.

Findings

It is found that the actions induced by the moving load could be comparable or larger than those caused by the earthquake on bridges whose mass is not too large in comparison to the vehicle mass.

Research limitations/implications

The developed method will be applied to a broader choice of examples and more reliable conclusions made.

Practical implications

There are bridges where it would be appropriate to perform moving vehicle dynamic analysis, in which case the vertical earthquake actions could be neglected in the analysis.

Originality/value

In order to assess actions from moving vehicles, Newmark method has been generalized in a novel way. Paper describes vector formulation of Newmark method that permits free mixing of integration parameters that could vary from node to node. The method is advantageous for moving load analysis where loading conditions of nodes change in time.

Citation

Kožar, I. (2009), "Security aspects of vertical actions on bridge structure: Comparison of earthquake and vehicle induced dynamical forces", Engineering Computations, Vol. 26 No. 1/2, pp. 145-165. https://doi.org/10.1108/02644400910924843