Vehicles and gross vehicle weight

Chapter 2 introduces traffic data and its implications for bridge live load model development. Nowadays, data on vehicle loads are collected using Weigh-in-Motion (WIM) stations. WIM stations continuously record information about gross vehicle weight (GVW), axle loads, axles spacing, etc. The WIM data collection, quality control, and analysis procedures are discussed. The raw data has to be verified to eliminate potential errors using filters to remove suspicious records. The measurements can serve as a basis for the development of design live loads and live load factors. Bridge design requires a prediction of future maximum expected loads, so an approach to probabilistic methods of extrapolation of live load effects is presented. Finally, this chapter summarizes the process of deriving load factors using reliability-based calibration procedures.