America’s transportation infrastructure—particularly the Interstate Highway System— is past its original anticipated design life and its age is showing. The age of the system coupled with high user demand and limited financial resources requires innovative thinking from the design engineer. One solution frequently utilized is the replacement of deficient bridges with prefabricated structures. The prefabricated alternative is typically less expensive to construct, easier to maintain, and can be built with significantly less service disruption to the traveling public.
This approach can be utilized for stream crossings and for grade separation structures. The systematic approach for selecting an appropriate structure is similar for both applications. The designer must determine an appropriately sized structure; determine if any of the existing structure will be reused; determine how much of the structure will remain in place; assess the constructability of the proposed replacement structure; and determine the structural capacity of the proposed structure.
