One of the causes of fatigue damage in steel bridges is high stresses due to traffic loads. The Bridge Weigh-in-Motion (BWIM) is a system to measure the traffic loads in the bridge. The response induced by a vehicle which does not enter the measurement section may be sometimes observed, even though the target bridge is not a continuous girder bridge. Based on synthesized observation data, the effect of considering the pre-entry response on the results of axle weight estimation is studied first. Then using the measured data, the effect of pre-entry is examined. The relative error of estimated axle weight with the consideration of the pre-entry response was about 20% smaller than that without the consideration.
