Fatigue Load Model For the Design of Steel Bridges

This paper describes the procedures determining the fatigue load model for the design of highway bridges and suggests fatigue design truck. Efficient management of the bridges has become an increasing concern for those charged with maintaining highways and bridges. The volume and conditions of traffic with bridge type, geometry. configuration, and other factors, such as maintenance, determine the integrity and life expectancy of highway bridges and their components. Bridge weigh in motion (BWIM) system was selected and installed in a bridge on Kyungbu Highway to get the traffic data such as type of truck, axle distance and axle weight, etc. The BWIM system were successfully used to collect the data without stopping or slowing down the traffic. The data from BWIM system shows the wide range of axle weights and total weights which proves the effectiveness of the system. To evaluate the fatigue damage accumulation due to the traffic, normalized damage equation is derived. Two fatigue load models were proposed and fatigue load model 2, which was determined by utilizing heavier 21.1% of all truck data, shows close fatigue damage accumulation to the real fatigue damage curve for the span over 30m span.