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Duvall Slough Bridge #1136B (NE Woodinville Duvall Road) Re-Deck Project

Construction completed in summer 2024

The Duvall Slough bridge on NE Woodinville Duvall Road has a brand new deck and opened to traffic on August 27, 2024. 

Status update

September 2024

NE Woodinville Duvall Road at the Duvall Slough Bridge reopened to traffic on August 27 after the re-decking project was completed.

Crews will return for occasional daytime lane restrictions in On October 2, 2024. This work is weather dependent and can be rescheduled. Please visit MyCommute for the latest information and to see other area lane restrictions and road closures. 

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Overview

The Duvall Slough Bridge is located on NE Woodinville Duvall Road, east of West Snoqualmie Valley Road. King County removed the top half-inch of worn-out concrete on the bridge deck and replaced it with one-and-a-half inches of new concrete. The project also rebuilt both bridge approaches and repaired two bridge expansion joints. This work protects and extends the life of the bridge for 30 years or longer.

The work required a six-week-long road construction closure on NE Woodinville Duvall Road between State Route 203 (Main Street/Carnation Duvall Road) and West Snoqualmie Valley Road. The road had to be closed because the bridge is too narrow to keep a lane open and maintain a safe work area. In addition, there could not be any vibration from traffic when crews repave the concrete or work on the expansion joints.

Why this project is needed

More than 10,000 vehicles cross the Duvall Slough Bridge on NE Woodinville Duvall Road every day. Crews have previously temporarily closed the bridge to repair potholes and patch up cracked concrete many times over the years. The concrete driving surface was too damaged to rely on short-term repairs. Overlaying the concrete bridge deck, rebuilding the bridge approaches and improving the bridge expansion joints are critical to keeping this vital east-west corridor open to traffic for years to come.

What caused the bridge deck damage?

The 75-year-old concrete deck was cracked, prone to large potholes, and was nearly worn down to the steel rebar in some places. Water seeping through the cracks and thinning concrete continued to make the damage worse.

Why do the expansion joints need to be repaired?

The old expansion joints no longer allowed the concrete to expand and contract like it needs to. Repair of the expansion joints helps prevent cracking by allowing the new concrete re-deck to expand and contract like it should.

Project location

The project was located on NE Woodinville Duvall Road between West Snoqualmie Valley Road NE and West Snoqualmie River Road NE. Larger view (168KB)

Budget and funding sources

The preliminary estimated total project cost is $1.9 million. This project is funded by Federal grants.

Project timeline

  • February 2024 – Advertise to contractors
  • July and August 2024 – Construction
  • Late August 2024 – Project complete

Frequently asked questions

The bridge is too narrow to open a lane of traffic and maintain enough room for construction equipment and crews to do the work. Also, most of the work requires a still, calm surface. Vibration from busy traffic could cause problems with curing concrete and expansion joint repairs.
The repairs are expected to last for at least 30 years.
No, King County Road Services did not replace the concrete bridge deck in 2013. Instead, we overlayed the deck with additional concrete and installed a thin protective ‘epoxy aggregate’ (plastic resin mixed with gravel and sand) overlay coating over the bridge deck to help keep the added concrete intact. This type of repair is meant to last between five and ten years. It has been 11 years now. The 2024 bridge re-deck completely removed the top half-inch of concrete and replaced it with one-and-a-half inches of new concrete.
First, crews used high-intensity water pressure (hydro-demolition) to remove most of the existing concrete deck (approximately 0.5 inches deep, 639-feet long, 24-feet wide). Next, crews overlayed the entire length of the deck with new, 1.5-inch-thick concrete on top of the existing steel rebar. Once the concrete was in place, crews modified the expansion joints and rebuilt the bridge approaches on both sides of the span to meet the new raised deck height.
Aside from the worn-out concrete bridge deck and corroded expansion joints, all other parts of the Duvall Slough Bridge #1136B are in safe condition. It costs more than $50 million dollars to replace an entire bridge. The repairs we made in 2024 cost $1.9 million and will last for at least 30 years.
The Duvall Slough Bridge #1136B is 639 feet long and 24 feet wide.
The bridge is located on NE Woodinville Duvall Road, one of the busiest corridors in Unincorporated King County. Approximately 10,000 vehicles cross this bridge every day.

Photos

New deck on the Duvall Slough Bridge.

August 2024 – The new bridge deck is almost complete. The newly poured concrete has dried and is ready to bear weight.

 

Bridge deck after overlay pour.

August 2024 – Very specific conditions for air and ground temperature, and even wind speed, were required to ensure proper settlement of the concrete. Crews had to pour this overlay during the night to meet the specifications.

 

Geotextile wrap applied to bridge.

August 2024 – Geotextile wrap is used to stabilize the layers of compacted material.

 

Gravel material being applied to support new bridge approach.

August 2024 – Gravel material is compacted to support the new bridge approach. This project removes and rebuilds both bridge approaches.

 

Rebuilding the bridge approach.

August 2024 – Crewmembers rebuild the bridge approach area with rocks and gravel to improve the settlement issues at the approaches of the bridge.

 

Pressure washing the bridge deck.

August 2024 – Crews pressure wash the deck after removing the top layer of concrete with a hydro-demolisher. Cleaning the deck removes leftover debris to prepare the road for a new concrete surface.

 

A crewmember uses a large hose to vacuum the debris after hydrodemolition.

July 2024 – A crewmember uses a large hose to vacuum the debris after hydrodemolition. 

 

A bridge deck demolished by a high-pressure water tool to selectively remove concrete

July 2024 – The bridge deck was demolished by a high-pressure water tool to selectively remove concrete. Hydrodemolition creates no dust pollution and the water used during the process is collected and treated on site to minimize risk of contamination.  

 

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