The Federal Highway Administration (FHWA) Long-Term Bridge Performance (LTBP) Program carried out a field demonstration of new and emerging bridge assessment technologies for the Pennsylvania Department of Transportation (PennDOT). The demonstration occurred in Coraopolis, PA on a two span steel multigirder bridge. As this effort was a technology demonstration, selection of a candidate bridge focused on balancing access and traffic constraints and structural performance concerns. Part of a multidisciplinary team, Intelligent Infrastructure Systems had three major responsibilities: (1) facilitating the test through structure selection, on-site coordination and support, (2) development of a 3D finite element model of the bridge, design of an instrumentation plan for traditional live load testing on the structure, and execution of that testing, and finally (3) demonstration of the THMPER™ (Targeted Hits for Modal Parameter Estimation and Rating) and RAMPS systems.
THMPER™ combines a self-contained rapid modal testing trailer and streamlined data processing software to extract modal parameters. RAMPS builds and updates a finite element model, leaving the user with a reliable model updated with field-collected data in a fraction of the time required for traditional impact testing.
Intelligent Infrastructure Systems and Drexel University executed the modeling and live load testing which served as the baseline comparison for the demonstration of the THMPER™ and RAMPS. THMPER™ was deployed on the demonstration bridge, requiring merely thirty minutes of traffic interruption in total to collect data from the entire bridge. The extracted modal parameters agree with those determined from a traditional impact test as well as a finite element model calibrated based on live load testing data.