Experimental crash testing has demonstrated that static design procedures are inadequate to predict the complex interaction that occurs when an errant vehicle strikes a bridgerail system. Following the publication and adoption of the Canadian Highway Bridge Design Code (CAN/CSA-S6-00) by Alberta Transportation (AT), a series of standard drawings incorporating the new safety concepts were developed by AT for use on new construction projects. It was also decided that in addition to applying the improved standards for new construction, it would be prudent to apply the same safety concepts to the upgrading of existing bridgerail systems whenever practical. This paper will give an overview of the development of the Guidelines, and the discussion will include the evaluation of existing AT bridgerail systems and approach guardrail transitions, and the needs to upgrade with respect to safety. The paper will also discuss prioritizing projects using cost-benefit analysis, based on encroachment rates, severity indices, present value costs, etc.
Samenvatting