Dynamic amplification factor of continuous versus simply supported bridges due to the action of a moving vehicle

Research to date on Dynamic Amplification Factors (DAFs) caused by traffic loading, mostly focused on simply supported bridges, is extended here to multiple-span continuous bridges. Emphasis is placed upon assessing the DAF of hogging bending moments, which has not been sufficiently addressed in the literature. Vehicle-bridge interaction simulations are employed to analyze the response of a finite element discretized beam subjected to the crossing of two vehicle types: a 2-axle-truck and a 5-axle truck-trailer. Road irregularities are randomly generated for two ISO roughness classes. Noticeable differences appear between DAF of mid-span moment in a simply supported beam, and DAFs of the mid-span sagging moment and of the hogging moment over the internal support in a continuous multiple-span beam. Although the critical location of the maximum static moment over the internal support may indicate that DAF of hogging moment would have to be relatively small, this paper provides evidence that this is not always the case, and that DAFs of hogging moments can be as significant as DAF of sagging moments.