Impact factors of concrete girders coping with train speed-up

Abstract

The dynamic response of railway bridges is a problem of the resonant response of girders that occurs because bridges are excited at a constant period by running trains. In general, this is referred to as "the speed effect of multiple-axle moving loads." In this study, vehicle running tests were performed to examine 56 bridges of various structural types and span lengths. The impact factor was measured to be about 1.0 on four girders, and the damping ratio as low as 0.02. Based on the results of these running tests and numerical analysis, a revision of the railway design standard was proposed, to cope with the speed-up of trains.