  During past few decades, several studies have been conducted to characterize
the performance of in-service girder-type bridge superstructures under
operating conditions. Few of these efforts have focused on evaluating the
actual response of the bridge systems, especially beyond the elastic limit of
their behavior, and correlating the impact of damage to the overall system
behavior. In practice, most of the in-service bridge superstructures behave
elastically under the routine daily traffic; however, existing damage and
deteriorating conditions would significantly influence different aspects of the
structural performance including reserve capacity, resilience and remaining
service-life. The main purpose of this study is to evaluate the response of
composite steel girder bridges under the effect of subsurface delamination in
the reinforced concrete deck. Commercial finite element computer software,
ANSYS, was implemented to perform a nonlinear analysis on a representative
single-span simply supported bridge superstructure. The system failure
characteristics were captured in the numerical models by incorporating
different sources of material non-linearities including cracking/crushing in
the concrete and plasticity in steel components. Upon validation, non-linear
behavior of the system with both intact and degraded configurations was used to
evaluate the impact of integrated damage mechanism on the overall system
performance. Reserve capacity of this bridge superstructure was also determined
with respect to the nominal element-level design capacity. As vision to the
future path, this framework can be implemented to evaluate the performance of
other in-service bridges degraded under the effect of different damage
scenarios, thus providing a mechanism to determine a measure of capacity,
resilience and remaining service-life.
