Dynamic behavior of aluminum deck-on-steel girder bridges under vehicular traffic loads considering the effect of road roughness

Aluminium as a structural material is known for its lightweight, which facilitates easy transportation and installation, and reduces foundation requirements. However, this lightweight characteristic makes it sensitive to excitations from vehicular traffic leading to dominating dynamic design over the static one. The dynamic design of highway bridges by the Canadian Highway Bridge Design Code (CSA S6-19) is based on the concept of equivalent dynamic amplification factors (DAF), which were derived largely based on the observations from bridges constructed with traditional materials such as concrete, wood and steel. It is prudent to evaluate whether these factors are applicable to lightweight bridges made with extruded aluminium decks. In addition, since road roughness plays an important role in the dynamic behaviour of a bridge, it is important to consider the influence of roughness on the bridge vibration response. The objective of this research is to investigate the dynamic behaviour of aluminium deck-on-steel girder bridges under vehicular loads considering the effect of road roughness, and consequently evaluate the applicability of the current design DAFs for such structures. For this purpose, numerical models have been developed in Abaqus for a range of selected bridge configurations and loading parameters and subsequently the key observations and conclusions from the numerical analysis have been presented in this paper.