The Van Buren Bridge will be discussed by the Corvallis City Council during its work session at 4 p.m. Thursday, Aug. 6. There are plans for a $70 million replacement bridge crossing the Willamette River.
Historic preservationists want to slide the old bridge 175-feet south for use by pedestrians and cyclists. A report released by Preservation Works lays out the proposed bridge relocation plan. The report says the bridge could be moved for $6 million, which they say is significantly less than what was estimated by the Oregon Department of Transportation.
The relocation report was prepared by Smith Monroe Gray, Inc. Engineers for Preservation Works and says it delivers the option requested from ODOT for the past nine months as part of the new Van Buren Bridge project.
“We believe that this option should be included in the current project and paid for by ODOT,” Preservation Works said in a press release. “It is the best possible outcome for the new Van Buren Bridge project and the citizens of Corvallis, Benton County and Linn County.”
Currently, ODOT is advertising the existing truss bridge for sale, with stipulated requirements for its relocation or demolition that allow the proposed work to proceed unhindered by the existing bridge, according to the Preservation Works report.
The new replacement bridge project is funded by infrastructure resources under Oregon House Bill 217, which involves federal funding as well. Stipulations of the funding may not allow offsetting cost savings, which may have been possible by use of the existing bridge as a detour bridge during construction or by reducing the multi-use aspects of the new bridge (pedestrian, bicycle, etc.).
“Although the existing bridge has historic significance, it is not currently listed on the National Historic Registry,” the Preservation Works report said.
The current Van Buren Avenue Bridge is a steel through-truss style that came into use in 1913, crossing from Corvallis into Linn County on OR34/Highway 210EB, and carrying a single lane of eastbound traffic. The newly designed replacement will have increased vehicle lanes.
The original bridge (ODOT Bridge No. 02728) was built in 1913 by Andrew J. Porter and the Coast Bridge Company. It has been repainted and the deck surface replaced, along with other maintenance in the past 22 years, at an approximate cost of more than $3 million over the last 22 years. There is a sidewalk structure appended to the south side of the trusses, constructed of wood stringers, wood plank deck, and a wood pedestrian guardrail.
“This rare pin-connected swing span type bridge is historically significant and an example of bridge engineering and construction over navigable waterways in the early twentieth century,” the report said.
The bridge slide process involves a number of steps. Steels support stands will be founded on the deck of the work bridge, continuous slider beams will be placed on the stands, and the trusses will be jacked up from the existing supports, then placed on sled beams at piers one, two, and four. At pier three, openings will be cut in the walls in places to accept the slider and sled beam.
The sled beams will be preloaded with the anticipated weight of the swing spans, rotating system, and top slab of pier three. The top slab will be cut free from the supporting cylindrical walls, and all three truss spans will be pulled simultaneously along the slider beams to the new location. The spans will then be lowered onto new support piers.
The cost for preparing new seismic-resilient substructures, moving the truss spans, performing repair and upgrades, and construction of approach spans and ramps is estimated to be $6 million. The report said there are few offsetting costs because using the existing bridge as a detour and/or reducing pedestrian and bicycle requirements on the new bridge were disallowed during the project programming phase. However, not having the cost of demolition and disposal is a cost savings.
“The benefits of relocating and repurposing the existing Van Buren truss spans make this project feasible from the perspective of costs and future use of the bridge,” the report said. “The project will provide a very friendly pedestrian crossing in terms of profile grades and elevation change when compared to the proposed new bridge.”
By Cody Mann