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Ames Lake Trestle Bridge Replacement Project

Project anticipated to begin in late June 2024

Two engineers inspect the Ames Lake bridge from the bucket of an under-bridge-inspection-truck (UBIT) truck.

Two engineers inspect the Ames Lake Trestle Bridge from the bucket of an under-bridge-inspection-truck (UBIT) truck. The bridge will be replaced in 2024. 

Status update

April 2024

Online community meeting:

Got questions? Submit them to https://tinyurl.com/AmesLakeMeeting and we’ll do our best to address them during the meeting.

To request translation services for this meeting, please call 206-477-8100 (Relay 711)

Para solicitar esta información en Español, sírvase llamar al 206-477-8100 (Relevo: 711) o envíe un mensaje de correo electrónico a abresslour@kingcounty.gov.

Ames Lake-Carnation Road NE, between West Snoqualmie Valley Road NE and NE 52nd Street, will be closed at the bridge location for up to eight (8) months starting in late June 2024. Construction will not start until after the school year has concluded.

From March 25 to May 3 from 7 a.m. to 5 p.m. daily on weekdays, expect occasional lane restrictions due to utility relocation work. The bridge will remain open for traffic. 

View project flyer.

Visit MyCommute for more information.

24/7 Road Helpline

24/7 Road Helpline

Call us for help at 206-477-8100 or 1-800-527-6237 with road maintenance and traffic safety issues in unincorporated King County — 24 hours a day

Project overview

This project replaces the 100-year-old Ames Lake Trestle Bridge with a wider structure and straighter bridge approaches. The improvements are designed to increase sight distance for drivers and provide a safe, unrestricted crossing for trucks and vehicles of all sizes. In addition, the new bridge will be designed to have less environmental impact on Ames Creek and the surrounding wetlands.

The new bridge will be built in the same location as the existing bridge and have no weight restrictions. The road will be closed for the duration of the new bridge construction and traffic must use an alternate route. King County will host an online community meeting about this project on April 24, 2024 and construction is anticipated to begin in late June 2024. The new bridge should be mostly complete in early March 2025.

The bridge crosses Ames Creek on Ames Lake-Carnation Road NE, in rural unincorporated King County between Redmond, WA and Carnation, WA. View larger image (347KB)

Why is King County replacing the bridge?

The Ames Lake Trestle Bridge was built 100 years ago and was originally designed with narrow lanes for much smaller vehicles compared with what we see on the road today. The bridge has a posted weight restriction for specific large trucks and specialized hauling vehicles. Replacing the bridge will provide a safer, unrestricted crossing for the community.

The original timber piles that support the deck are decaying. Over time, the poor condition of the piles could prohibit large trucks and emergency vehicles from crossing, which eventually would require the bridge to be shut down completely.

Project timeline

Spring 2024:
  • Online community meeting via Zoom on Wednesday, April 24, 7 p.m. to 8 p.m. https://kingcounty.zoom.us/j/87130877463 Meeting ID: 871 3087 7463 Passcode: AmesLake24 
  • March 25 to May 3 from 7 a.m. to 5 p.m. on weekdays, utility relocation at the bridge site will require occasional lane restrictions.

Summer 2024:

  • The project is expected to begin on June 24, 2024. It will take approximately eight (8) months to complete.
  • During construction, Ames Lake-Carnation Road NE, between W. Snoqualmie Valley Road NE and NE 52nd Street, will be closed to all vehicles, bicycles, and pedestrians at the bridge location. 
  • There will be no posted detour as there are many alternate routes available in the area. All traffic, including emergency vehicles and school buses, must use an alternate route for the entire eight-month-long construction period. The project team will notify Google Maps of the closure. 
  • The project team will notify Google Maps of the closure.

Fall 2024 thru winter 2025:

  • The bridge will be under construction and closed to all traffic, including emergency vehicles and school buses, through early March 2025. 
  • The new bridge is anticipated to be complete in early March 2025.

Spring 2025:

  • Major construction complete.

Map of alternate routes to use during construction

The roads shown in purple above are all the alternate routes that can be used when Ames Lake Trestle Bridge is under construction. About 1,900 vehicles cross this bridge daily and there is no official detour route for this project. We are coordinating with school districts and emergency services. Additionally, WSDOT is aware of the project, and we will monitor conditions.   View larger image (946KB)

What to expect during construction 

The project team will protect the trees in the creek and will work to prevent dust and dirt caused by construction work from spreading in the air.  In addition, people living near the work area might experience the following while the bridge is being removed and replaced:

  • Noise and odor from sawcutting, jackhammers, excavators, generators and pumps.
  • Trucks hauling materials to and from the construction site. 
  • Large construction cranes in the roadway. 

After the new bridge is opened to traffic, crews will continue low impact restoration work including plantings and site clean-up.

 

Future bridge layout

The new Ames Lake Trestle Bridge will be wider, straighter and safer than the existing bridge. There also will be improved visibility for oncoming traffic. All of these improvements will allow those coming out of adjacent driveways to see farther down the road. 

Graphic showing the future bridge layout.

The new bridge will be in the same place as the existing bridge. Building it in the same spot requires less ground shoring and leveling (grading). It also minimizes the size of the retaining walls that will be required.

Environmental improvements

The new bridge is designed to minimize and prevent environmental impacts on Ames Creek and the surrounding wetlands.

This project will:

  • Improve fish and wildlife habitat.
  • Improve water quality.
  • Reduce erosion.

Project budget

The estimated cost of this project is $10.8 million. It is funded through local King County sources.

Photos

Official blue and yellow Ames Lake Trestle Bridge Project information signs

One of three official blue and yellow Ames Lake Trestle Bridge Project information signs located along Ames Lake-Carnation Road NE. The county expects to start work in late June 2024. Photo taken in November 2023.

 

View of the Ames Lake Bridge as seen from Ames Lake-Carnation Road NE while heading south toward NE Union Hill Road

A view of the Ames Lake Trestle Bridge as seen from Ames Lake-Carnation Road NE while heading south toward NE Union Hill Road. The bridge’s complete wooden support system, which spans the creek, remains hidden beneath the road and out of view from passing traffic. Photo taken in November 2023.

 

A sign provides details about which types of trucks are restricted from using the bridge

Most vehicles weighing more than 19 tons are currently too heavy to cross the Ames Lake Trestle Bridge. This sign, pictured above, provides details about which types of trucks are restricted from using the bridge. The new replacement bridge will not have any weight restrictions. Photo taken in November 2023.

 

Frequently asked questions

The Ames Lake Trestle Bridge was built 100 years ago and was originally designed with narrow lanes for much smaller vehicles compared with what we see on the road today. The bridge has a posted weight restriction for specific large trucks and specialized hauling vehicles. Replacing the bridge will provide a safer, unrestricted crossing for the community.

The original timber piles that support the deck are decaying. Over time, the poor condition of the piles could prohibit large trucks and emergency vehicles from crossing, which eventually would require the bridge to be shut down completely.
The new design removes vehicle weight restrictions and improves sight distance by widening and straightening the road. A wider and straighter road helps users on the bridge, and those coming out of adjacent driveways, to see farther down the road. In addition, the new bridge will be designed to have less environmental impact on Ames Creek and the surrounding wetlands.
The bridge crosses Ames Creek on Ames Lake-Carnation Road NE, in rural unincorporated King County between Redmond and Carnation.
We decided not to include a temporary bridge due to cost and traffic impact. The new bridge will cost significant less to build due to the small project footprint and absence of a temporary bridge. The county will be able to build the bridge much faster because it will be closed to traffic.

During the 8-month closure to replace the 100-year-old Ames Lake Trestle Bridge, Road Services is providing a map of alternate routes on the project website. Approximately 1,900 vehicles use the bridge daily. We also know that many people use map-based apps on their mobile phones and that those directions are often more efficient for travelers than one singular detour. 
Approximately 1,900 vehicles and 70 trucks cross the bridge every day. It is a County-designated snow route. Ames Lake-Carnation Road NE serves a growing population of single-family homes, farm and forest lands.
Yes. The bridge remains safe for passenger cars and trucks. The County restricts specific heavy trucks and specialized hauling vehicles, and the limits are posted near the bridge. These heavy vehicles will continue to be restricted until the new bridge is complete.

King County will continue to inspect and maintain the existing bridge regularly to ensure it is safe to use.
Yes, there are.

Current weight limits include:
Type 3: 21 tons
Type 3-S2: 34 tons

Single-unit vehicles:
3 axles or fewer: 21 tons
4 axles: 19 tons
5 axles: 22 tons
6 axles: 25 tons
7 axles: 28 tons

King County regularly inspects the bridges it is responsible for maintaining. If new restrictions are required based on these inspections and bridge load rating analysis, a notice will be posted on the bridge. The County will also note any new restrictions on the Bridge Weight Restrictions website.
The project will replace the bridge in the same location on Ames Lake-Carnation Road NE.
No. The new bridge will be built to current standards and will not have vehicle weight or size restrictions.
No. There will not be any access for drivers, pedestrians or emergency vehicles when the new bridge is under construction. The project does not plan to offer a signed detour route because there are several north-south alternate routes in the area that drivers can use to get around when this section of Ames Lake Carnation Road NE is closed to traffic.
The preliminary estimated total project cost is $10.8 million.
The King County Council adopted $12.7 million in funding within the Road Services Division 6-year Capital Improvement Program during the 2019 – 2020 biennial budget process. Additional funds for this project come from the Road Services Division Operating Budget.
The project will remove, transport, and dispose of the existing creosote-treated timber piles at an approved disposal facility.
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