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Pedestrians crossing the South Umpqua River in Green, Oregon are rewarded by several artistic flourishes鈥攍ookout areas with textured and stained concrete, columns with imprints of leaves and pinecones, and a powder coated handrail.

Project team + Stats

Location: Green, Oregon
Cost: $25.64 million
Start Date: March 2009
Completion Date: December 2010
Owner/Developer: Oregon Department of Transportation
Engineer: David Evans and Associates
General Contractor: Safeco Surety
Completion Contractor: Legacy Contracting Inc.

The new box girder bridge supports a 696-foot-long, concrete pedestrian bridge that is suspended beneath the main bridge by 88 cables. To support the cable assemblies, diaphragm beams were cast inside the post-tensioned box girder bridge at all 88 locations. On the west side, the pedestrian bridge continues over the river鈥檚 rocky bank for an additional 265 feet, where 10 columns drilled into the bedrock support it.

Construction was not without its challenges, however. The natural ruggedness of the terrain, fluctuations in the river and the existing railroad made construction of the bridge difficult.

In addition, the standard drill rig could not access one of the main bridge鈥檚 supporting bents because it was located at the base of a vertical rock, in a deep section of the river, and between the existing bridge and a railroad line. Due to these obstacles, the shafts at this fourth bent were dug by hand.

The team, led by Legacy Contracting Inc., pre-cast the pedestrian bridge in twenty-foot sections instead of having false work in the river. The pre-cast sections were then raised into position and the sections over the river were floated into place using a flexifloat.

Hanging forms were used to complete the closure pours between pre-cast sections. This strategy reduced the amount of time the team had to spend in the water, which eliminated some of the damage that construction would have caused to the river鈥檚 ecosystem.

Despite the project鈥檚 challenges, Jeff Howell, president of Legacy, said that everyone on the team eventually came together to build something the public will use for years.

鈥淓veryone has pride and ownership in that bridge,鈥� he said.