Ames Lake Trestle Bridge Replacement Project

Project overview

This project replaces the 100-year-old Ames Lake 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 a detour route. King County will host an online community meeting about this project in early 2024 and construction is anticipated to begin in March 2024. The new bridge should be complete in late fall 2024.

The bridge crosses Ames Creek on Ames Lake-Carnation Road NE, in rural unincorporated King County between Redmond and Carnation.

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

Winter 2024: 

• Online community meeting will be held in February, the date is to be announced.
• Utility relocation work at the bridge may require temporary lane restrictions or single-day full road closures ahead of construction. We will provide at least 48-hours advance notice when the bridge needs to be closed. 

Spring and summer 2024:

• The project is expected to begin in spring and will take approximately eight (8) months to complete.
• During construction, Ames Lake-Carnation Road, 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. 

Fall 2024: The new bridge is anticipated to reopen to all by the end of December. 

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 Bridge is under construction. There is no official detour route for this project.

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 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. 

 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

Photos