The bridge weigh-in-motion (WIM) algorithm is modified to calculate the dynamic amplitude of the bridge vibration in addition to the axle weights for any truck crossing over an instrumented bridge. The proposed method first finds dominant dynamic frequencies using a fourier analysis of the record of an end girder that carries little static but considerable dynamic effect. The frequencies determine dynamic "influence lines" with amplitudes that are found using the minimisation-of-error technique of the WIM algorithm. Preliminary results indicate that the proposed method is applicable for a large number of bridges where more traditional methods fail to predict the dynamic effects. Use of such an algorithm should facilitate the current trend of utilising field data in evaluating the safety of existing bridges.
Samenvatting