Traffic Considerations for Ontario Highway Bridge Design CodeA Historical Account

This chapter delves into the historical development and practical applications of the Ontario Bridge Formula (OBF), a critical tool in highway bridge design and evaluation. It begins with an overview of the OBF's origins in 1971, detailing its initial parameters and the subsequent load surveys that validated its effectiveness. The text explores the transition from imperial to metric units and the impact of this change on permissible axle weights and gross vehicle weights. A significant focus is placed on the dynamic considerations in bridge design, including the resonant vibrations observed in the Conestogo River Bridge and the development of dynamic load allowances. The chapter also discusses the evolution of live loading models for the Ontario Highway Bridge Design Code (OHBDC) and the introduction of the OHBD Truck, which reflects real-world vehicle configurations and load distributions. Additionally, it covers the development of deflection limits based on human perception of bridge vibration, providing a comprehensive understanding of serviceability criteria. The chapter concludes with an epilogue on the integration of the OHBDC with the Canadian Highway Bridge Design Code (CHBDC), highlighting the ongoing efforts to standardize bridge design practices across Canada.