Structural monitoring as a tool for the assessment of bridges

As bridge engineers, we reach conclusions about the safety of structures by relying on data from analytical models. How do we know that the assumptions these models are based on are correct? To answer this question, a monitoring programme using sensors was implemented during the structural assessment of a 287 m span steel tied-arch bridge on the Dutch highway network. During a full traffic closure, a predefined truck was driven across the bridge multiple times, while 89 gauges recorded strains at locations of interest on the structure. The recorded measurements were compared with the results derived from the analytical model used for the assessment. The model validation considered the structural health monitoring measurements and compared them with the response of the finite-element model under codified moving loads. The measured structural behaviour was used to calibrate the model, which ensured that the analysis and safety assessment of the bridge were based on a validated model. The use of monitoring programmes on existing structures enables the engineering community to work towards a method to capture structural behaviour more accurately without excessive effort and overly complex models.