Unnoticed by many Interstate 5 motorists passing over the Evans Creek Bridge, located north of Rogue River exit 48, is a strengthening project that provides the equivalent of an exoskeleton to the half-century old structure.
Evans Creek Bridge is undergoing a $1.2 million repair to extend its lifespan. One of 35 bridges from Medford to Grants Pass on I-5, the 51-year old bridge was scheduled for repairs to avoid load-carrying restrictions.
According to ODOT Bridge Maintenance Manager Bryan Mast, the project is a necessity. “Evans Creek Bridge has taken a real pounding over the past fifty
years,” said Mast.
The repairs involve injecting the cracks with epoxy before wrapping a fiber reinforced polymer (FRP) composite around the concrete girders. ODOT has used this repair method on numerous bridges over the past 15 years.
“The FRP wrap adds strength to the beams to help them resist traffic loads,” said Mast. “This repair is designed to provide the bridge with at least another 25 years of use. This approach is the most economical solution for the problem.”
FRP is defined as an engineering material that consists of thermosetting resin and fiber reinforcement. Installation of FRP is temperature and humidity sensitive. Preparations are tedious before the wrap can be applied. The surface of each concrete girder must be cleaned and sanded smooth. The sharp corners on each girder need to be rounded off to allow for the best adhesion.
“A large portion of the repair work also involves constructing work platforms and containment systems,” Mast said, “as all of the repair work occurs under the structure.”
Work platforms were installed underneath the bridge. During this period, traffic was reduced to a single lane at night with I-5 ramp closures at Rogue River. With the platforms in place, the crew can work during the day. However, once the repair work is completed, the same night-time traffic impacts are needed as the contractor tears down the work platforms.