With Canada’s aging infrastructure, rising interest rates, and rising cost of materials, asset
management is at the forefront of transportation agencies priorities across Canada. Owners of
water and transportation buried structures crossings are faced with decisions to rehabilitate
the structure, remove and replace or keep as-is. An integral part of the assessment of the
existing crossing is load rating or evaluation of the structure. The Canadian Highway Bridge
Design Code (CHBDC) CSA S6-19 excluded buried structures, commonly referred to as culverts
or buried bridges, from the evaluation section that outlines the detailed design process for load
rating of existing structures. In the upcoming CHBDC S6-25 version, evaluation of buried
structures is addressed with additional special provisions that guides the designer/evaluator to
determine the target reliability index for the ultimate limit states and determine the load rating
of the structure. In this paper, the updated provisions will be discussed and a practical design
example for load rating of buried structures will be presented.
