Structural Health Monitoring of a Steel Railway Bridge for Increased Axle Loads

摘要

A large proportion of the existing bridge infrastructure network are relatively old, past their design life and have much larger loads running on them than had been considered in their design. Predicting the present behaviour of these systems, given these increased loads, makes structural health monitoring imperative as a tool to assess the present condition and the safety of the remaining life. In this paper it is shown that using a short measurement period, that is representative of the repetitive load on the bridge, and correlating the estimated fatigue life with the annual tonnage could give good fatigue assessment without having to resort to a significantly more expensive continuous monitoring of the structure. A site-validated numerical model is built, which provides an estimate of the present condition. This model is then used to estimate the loads coming on the bridge during the measurement period. The loads are then correlated with existing traffic data to give an estimate of the annual traffic tonnage. Good estimates of the annual traffic tonnage using this method show that the measurement period is representative and hence increase confidence on the validity of the remaining life estimated.