The effect of road roughness on vehicle-bridge interaction modeling

The study of the bridge response under moving loads is commonly investigated with two alternative approaches. One approach represents the vehicle as a moving load, the other with sprung mass models. This study is aimed to compare the two approaches and evaluate the difference in their accuracy to assess if there are cases where vehicle bridge-interaction modelling (i.e. the use of sprung mass models) is needed to accurately estimate the bridge response. For this purpose, both a moving load model and a one degree of freedom sprung mass model have been implemented and used to compare the bridge response under different road roughness. The probabilistic distributions of two indicators, used to compare the bridge displacement responses in three roughness scenarios with variable velocity and different vehicle mass and dynamics, are derived through Montecarlo simulations. It is found that an increasing level of road roughness modelled according to ISO-8608 increases the differences between the predictions of the models.