Laboratory and Field Testing of Composite Bridge Superstructure

TLDR

Bridge rehabilitation using a hybrid fiber‑reinforced polymeric composite was recently completed at the Tom's Creek Bridge in Blacksburg, Va. The study built and tested a full‑scale mock‑up of the bridge in the laboratory to verify the design and address construction issues before rehabilitation. The project replaced the bridge superstructure with a glue‑laminated timber deck on composite girders, constructed a full‑scale mock‑up for laboratory testing, and performed field tests under controlled vehicle loads to evaluate service‑load deflections, girder strains, load distribution, composite action, interpanel deck deflections, and impact factor. Field tests revealed a service load deflection of L/400 under moving loads, a high factor of safety for the composite members, and established a baseline for future durability assessments.

Abstract

Bridge rehabilitation utilizing a hybrid fiber-reinforced polymeric composite has recently been completed in Blacksburg, Va. This project involved replacing the superstructure in the Tom's Creek Bridge, a rural short-span traffic bridge with a timber deck and corroded steel girders, with a glue-laminated timber deck on composite girders. To verify the bridge design and to address construction issues prior to the rehabilitation, a full-scale mock-up of the bridge was built and tested in the laboratory. This setup utilized the actual composite beams, glue-laminated timber deck panels, and the skewed geometry implemented in the rehabilitation. Following rehabilitation, the bridge was field tested under controlled conditions (vehicle load and position). Both tests examined service load deflections, girder strains, load distribution, degree of composite action, interpanel deck deflections, and impact factor. The field test results indicate a service load deflection of L/400 under moving loads and a high factor of safety in the composite members against material failure. The data from the field test serve as a baseline reference for future field durability assessments as part of a long-term performance and durability study.