35th Ave Project Milestones

Significant Milestones Achieved on Mill Creek’s 35th Avenue SE Reconstruction Project
Posted on 11/16/2018
An aerial view of the project site as of Nov. 9The City of Mill Creek’s 35th Avenue SE reconstruction project has achieved several significant milestones.

As of Nov. 14, all 505 pin piles are installed. The pile-driving work began in August and took several months to complete as the six-inch diameter pin piles were driven through a large peat deposit to load-bearing ground. The average depth was 37 feet below ground. The bridge and roadway on either side of the bridge will be supported by the pin piles.

“Completion of the geotechnical aspect of the project, namely the installation of the pin piles, is a significant milestone in the construction phase because of the sheer number of pin piles and the depths to which that they needed to be driven,” said Gina Hortillosa, director of Public Works and Development Services.

Crews also removed two 54-inch culverts to restore fish passage to the area, which was a change order to the original project. Thomas Lake is immediately to the east of the roadway, and Penny Creek is a fish bearing stream that crosses underneath the roadway. All fish-blocking culverts in the state must be removed by 2030. Shortly after project approval, the City received the permits to remove the culverts. The ability to complete the culvert removal in 2018 means that the City would not need to reclose the roadway in future years to comply with this federal regulation.

The bridge abutments are built and bridge concrete work is underway. Other work on the project site includes rebuilding concrete sidewalks with curbs and gutters, landscaping, and installing fencing and signs.

The project now is slated to open in March 2019, depending on weather. The original project timeline cited eight months to complete the work.

“This slight delay to open in March is due to a combination of factors including the removal of the two culverts and a labor market shortage,” said Hortillosa. “However, the City is working closely with the contractors to ensure we limit impacts to our community members.”

Video of the project site from Nov. 14 is available at https://youtu.be/6vusklbLMoY.

35th Avenue SE is a three-lane minor arterial in Mill Creek that carries approximately 15,000 vehicles per day. The road was widened by Snohomish County in 2003 by using lightweight fill on top of a large peat deposit. The road has been continually settling since annexation by the City in 2005. The rate of settlement has slowed, but portions of the road have settled over two inches in the past three years and two feet over the past 10 years. The reconstruction project is fixing the road between 141st Street SE and 144th Street SE to eliminate flooding and associated road closures. Work includes driving approximately 500 pin-piles through the peat into good bearing soil, constructing a concrete slab on top of the pilings, and then reconstructing and elevating the roadway on top of lightweight concrete fill. More project information is available at www.cityofmillcreek.com/35th.