ABSTRACT
ABSTRACT: The strength capacity of bridges predicted by most current design codes is based on the philosophy of computing the capacity of individual members for various force effects (e.g., negative bending, positive bending, shear). However, bridges (especially those with steel superstructures) have significant load redistribution capability; thus, the ultimate load that may be resisted by the system is likely significantly higher than the ultimate load that is computed based on the strength of individual members. While the ultimate capacity of individual bridge members is fairly well understood, the ultimate capacity of a bridge “system” is not. Understanding this system behavior is complicated by the fact that load redistribution occurs only after the structure begins to behave inelastically, which means that full-scale tests of in-service bridges are not possible. Therefore, the best candidate for this type of ultimate capacity test is a decommissioned bridge. This paper discusses two such ultimate capacity tests (one completed and one planned) of bridges owned by the Delaware River and Bay Authority, which is currently in the process of decommissioning several bridges due to roadway realignment. This paper provides details of the testing program, as well as the test results to date.
