Seismic performance-based design of bridges with quantitative local performance criteria

Performance based design of bridges for earthquake resistance is still not explicitly used in design. However, most codes specify a level of performance for bridges under various earthquake inputs. In principle, design rules suggested in the code should meet stipulated performance criteria. However, it has been highlighted in the past that design rules are not directly related with stipulated performance criteria. After the presentation of performance criteria and their relation with post-earthquake functional requirements, the article examines the case of the Canadian Bridge Design Code (CAN/CSA-S6-06). Performance of bridges designed with this code is predicted and compared to expected levels. It is shown that compliance with design rule does not guarantee an adequate performance. This article attempts to correlate qualitative performance criteria with post-earthquake functional requirements, and critically examines code specified design rules and their cost effectiveness. Some implicit design rules are proposed to design new bridges.