Load rating of an in-service bridge integrating Bridge Weigh-in-Motion data and load test results

Old bridges subjected to current service loads are affected by the increased traffic flow and higher load-carrying capacity of new trucks. For structural assessment, knowing the actual loads over the bridge is crucial to obtain realistic results. Bridge Weigh-in-Motion (B-WIM) system facilitates decisions such as posting, construction of a new bridge, reinforcement, or rehabilitation of the structure since it is possible to know the actual loads. In this study, B-WIM data and load tests results are integrated to perform the load rating of an in-service bridge, located in Cali, Colombia. The bridge has prestressed girders with severe deterioration. The sensors deployed are strain gauges and a video camera for speed and axle identification, and for vehicle weight estimation. Data were analyzed for a critical load case and a strain threshold was proposed to trigger possible overloading events. Distribution factors, dynamic amplification factors, and the live-load factor were analyzed for in-service data. Important variations in the load rating factor were observed using in-service data.