Dynamic Amplification of Curved Beams Subjected to a Moving Point Load

Abstract

Assessment of masonry railway arch bridges are typically conducted using static loads. To account for the increase in structural response due to the dynamic application of loads, amplification factors are prescribed by the codes. These amplification factors have been derived from extensive large-scale laboratory testing on model concrete and steel bridges, carried out in the 1970s. Analytical solutions to the dynamic response of an undamped simply supported beam to moving loads demonstrate general agreement with these tests, and form the basis of the formulae used to determine dynamic amplification factors. This paper investigates the suitability of applying the dynamic amplification formulae to masonry arches. In particular, the critical role of determinant length and the chosen vibration mode and frequency is considered. To achieve this, the dynamic response of a damped two-hinged circular arch due to a moving point load is evaluated using Galerkin’s method. Solutions are compared to classical solutions and finite element analysis results for an instrumented single span arch, to highlight the limitations of codified formulae.