Development of Standard Fatigue Vehicle Force Models Based on Actual Traffic Data by Weigh-In-Motion System

Fatigue damage caused by vehicle-induced forces is a critical factor that affects the safety and the longevity of steel box girder bridges. Accurate vehicle force models are essential for quantifying fatigue in the design and the evaluation of bridge structures. Vehicle forces are random and exhibit significant variations, so to accurately determine a statistical distribution, a large amount of information and measurements is required. In this study, vehicle traffic information gathered by a weigh-in-motion (WIM) system at the Xihoumen Bridge, an over-water suspension bridge in Zhoushan, China, was analyzed for data such as the vehicle type, the gross weight, the axle weight (force), and the wheelbase. New insights into the analysis of measured vehicle information to obtain vehicle fatigue forces required for numerical simulations were gained. In addition, methods to determine various important vehicle parameters such as gross and axle weights and wheelbase were described. These techniques can be used to determine vehicle-induced fatigue forces for bridge structures.