Measurements of bridge dynamic amplification factor using bridge weigh-in-motion data

Abstract

The dynamic component of bridge traffic loading is commonly taken into account with a Dynamic Amplification Factor (DAF)—the ratio between the dynamic and static load effects on a bridge. In the design codes, this factor is generally more conservative than in reality. Recently a new method of calculation of this factor had been developed. Data from 15 different bridges have been analysed since then and this paper presents the results of the analyses. The background for Bridge Weigh-in-Motion is given, and the most recent method for DAF calculation is described. The sites from which the data originated are presented, and the selection of data discussed. The results of the analyses are presented and discussed and some examples of DAF calculations are shown. Data from the considered sites have invariably demonstrated a DAF decrease with increasing axle load. This is a significant result, especially for assessment of existing structures, since it is beneficial to use measured structural parameters to optimise structural analysis.