The Swift Creek Bridge is being replaced because the old bridge was originally built in 1957 and endured decades of freeze-thaw wear and tear.
(McCullough Construction photo)
Crews from McCullough Construction Inc. are eager to complete the California Department of Transportation's (Caltrans) $14 million replacement of the Swift Creek Bridge on State Route 3 in Trinity County, a project that is 90 percent complete. The work is anticipated to be complete in late spring or summer.
The initiative is replacing the existing bridge, a 168-ft. long, two-span, reinforced concrete T-girder bridge with seat type abutments and a pier wall supported on spread footings with one-lane in each direction.
The work is taking place approximately 1 mi. south of Trinity Center, to a half-mile north of Trinity Center along SR 3.
The original bridge was constructed in 1957. The new structure is a two-span, precast/prestressed, wide flange concrete girder bridge with the same number of lanes and two standard 8-ft. wide shoulders. California ST-70S bridge rail that is see through and side mounted is being installed.
General roadway paving improvements along the route are being executed: standard width 8-ft.-wide shoulders; increased horizontal curve radius from 350 ft. to 587 ft.; and a raised roadway profile.
The old bridge is being replaced with a new bridge, on a new alignment. Additionally, a bottomless large arched steel culvert was placed to improve fish passage at Rancheria Creek.
"There is currently some minor change order work involving some of the guardrail and culvert installation," said William Barnes, Caltrans project engineer. "This should be a short duration, while the weather is good. At this time, the main ‘plan of attack' is to demolish the old bridge, clean up and be done. Due to permitting restrictions in Swift Creek, as well as some internal issues, we do not anticipate beginning the demolition until mid-August. Conclusion of the demolition, and the project, should occur prior to mid-October."
Barnes discussed some of the challenges that have impacted the bridge replacement.
"There are always challenges," he said, "or Caltrans wouldn't hire engineers to administer the contracts. This project had some delays caused by the need for utility relocations, some environmental restrictions, and the need to respond during the wildfires. Our plan was to have completed the demolition and been done last winter, however due to delays in getting fiber optic lines moved from the old to new bridge, and the wetter earlier and heavier weather we had this past winter, we were unable to get it done.
"Our permits only allow work within the Swift Creek channel when flows are low, and without approval, only between June 15 and October 15," he added. "We had an exception to go until Nov. 15 last year, since flows were low. This year, flows are expected to be higher, which is also part of the reason that we are waiting until August to begin the demolition."
Aside from the challenges that were pointed out, Barnes stated: "I can't really think of anything out of the ordinary [that was a challenge] on this project."
Equipment utilized for the construction includes cranes, excavators, dozers, loaders, rollers, pavers and other standard equipment. McCullough purchases and rents equipment from local and regional dealerships.
Peak construction periods has a considerable number of McCullough and subcontractor employees on-site.
"The Swift Creek Bridge is being replaced because the old bridge was originally built in 1957 and endured decades of freeze-thaw wear and tear," said Kurt Villavicencio, public information officer, Caltrans District 2. "Inspections over the years showed significant deterioration on the deck, abutment, piers and wingwalls. This project is about a decade in the making and pivotal to keeping the traffic moving along the State Route 3 Weaverville to Yreka Corridor. These types of bridges play an instrumental part in keeping our communities connected.
"SR-3 serves as a minor arterial at this location," he added. "This highway section carries local, recreational, and commercial traffic in the North Trinity Lake resort area and connects northern Trinity County and Siskiyou County to Weaverville. Route 3 is a USFS Designated Scenic Byway adjacent to Shasta-Trinity USFS lands. This bridge and section of highway serve as a critical link to the local system."
A new bridge is needed.
"The existing bridge deck has a history of freeze-thaw damage," said Villavicencio. "The deck was replaced in 1986 and it was recommended to be replaced again based on the 2005 bridge inspection report from Caltrans Structure Maintenance & Investigations [SM&I]. It was determined that the deck replacement would not be cost effective."
On a daily basis, the bridge carries 526 cars and trucks. CEG
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