If you drive on Interstate 405 near the State Route 167 interchange in Renton, then you have probably noticed a lot of activity throughout the past year. Since breaking ground in September 2016, we’ve been hard at work, making progress and reaching many milestones for the I-405/SR 167 Interchange Direct Connector Project.
The Direct Connector will be a flyover ramp connecting the HOT lanes on SR 167 with the carpool lanes on I-405, which will reduce weaving and improve traffic flow at this heavily congested area. Our contractor is scheduled to complete the project by mid-2019, but as of Jan. 1, the project is already halfway complete in terms of the milestones it has met.
Let’s dig a little deeper into what exactly our crews have finished so far and what they have left to complete.
Shifting into place: Reconfiguring traffic to create safe work zones
Back in May, our crews shifted traffic on southbound I-405 to the inside of the freeway and reconfigured the Rainier Avenue South and SR 167 exits. This was necessary to create safe work zones for construction crews to begin building the future flyover ramp.
There are still two other traffic shifts left for crews to implement so they can safely finish work for the project. We have tentatively scheduled the second major traffic shift, which will push lanes of SR 167 and I-405 toward the outside of the highway, for this January and February.
Moving a noise wall and planting trees
In the spring and summer of 2017, crews finished relocating an existing noise wall about 100 feet south on a large hillside in the Talbot Hill neighborhood. In early July, they began hauling 80,000 cubic yards of dirt to make room for the future flyover ramp, which is enough dirt to fill almost 70 Boeing 747 airplanes! Crews moved the dirt from the Talbot hillside to the loops at the I-405/SR 167 interchange on and off-ramps.
During this time, they also planted trees and shrubs on the hillside across from Renton City Hall, but they still have to complete the landscaping work on the Talbot hillside. As part of our policy, we must follow rules about replanting trees after removing them for construction projects. Now that they have moved the dirt from the Talbot hillside, they can plant trees and shrubs in that location too.
Helping fish to “just keep swimming”
In the late summer through early fall of 2017, crews began working on other parts of the project that were not as dependent on good summer weather but just as important. We have been required to improve creeks and streams in the region by rebuilding fish barriers in addition to restoring and relocating the creeks and streams so the fish in those waterways can swim more freely. We call this work “fish passage,” and we typically divide the construction into three stages for our projects. For the Direct Connector Project, the first stage began in mid-September next to the northbound side of SR 167. Crews will be replacing a fish barrier with a passable culvert to help fish swim more easily through Rolling Hills Creek.
|A culvert is replacing a fish barrier to help fish swim more easily through Rolling Hills Creek as part of our Direct Connector project.|
We’ve completed the first stage of fish passage work, but still need to complete the second and third stages, which is when we will relocate and restore the stream for the fish culvert. This work will wrap up in August with a weekend closure of one direction of SR 167 in the area near the culvert construction.
Making the grade: Paving and widening SR 167
This past June, crews began strengthening the pavement on both northbound and southbound I-405 in the project area. They did this by installing dowel bars, which are short bars made of steel, in between the concrete panels of the freeway. These dowel bars help transfer vehicle weight evenly between the concrete panels.
In August, workers began grading, which means they flattened the ground to make it smooth and level before they could repave the roadway. Then they took advantage of the continued dry weather by starting and completing a significant stretch of paving in six weeks. They repaved 10.2 lane miles of southbound SR 167, which is equal to the length of about 89 Space Needles! When crews repaved the freeway in this area, they also widened it to make room for where the flyover ramp will begin or end on SR 167, just south of the I-405 interchange.
|In 2017, crews repaved and widened more than 10 miles of southbound SR 167, and strengthened the pavement by adding dowel bars which transfer vehicle weight evenly.|
Bridges: The Abridged Version
We have made huge progress on building new bridges alongside both directions of I-405 at the Talbot Road South exit. We’ve completed the substructures for the bridge on both directions of the freeway and have placed the girders, which are the main horizontal support of bridges. All that’s left to do is pour concrete for the bridge deck on the southbound side of I-405.
The direct connector flyover ramp will consist of 20 columns, which make up 10 piers. The flyover ramp will also have two abutments, which support the ends of a bridge or ramp. As of Jan. 1, crews have drilled 13 shafts and formed 11 columns, making up 5½ piers of the flyover ramp. They have even begun installing platforms on top of some of these columns in which crews have already placed concrete to form two crossbeams.
|Platforms to hold the new SR 167/I-405 Direct Connector flyover ramp have started to be constructed.|
Once they implement the next traffic shift, crews will continue to drill seven more shafts to build the foundations for more columns. They will also construct the abutments for the bridge, pour concrete for the rest of the columns, place crossbeams and pour the bridge deck.
While we have reached plenty of milestones in just a year, we still have many left to reach before we open the Direct Connector to traffic. We realize construction can be an inconvenience for nearby residents and motorists, but we hope you can share in the excitement of the major milestones we have reached for this project. Once our contract crews have finished building the ramp, it will help vehicles move more smoothly at this critical interchange. In the meantime, check out our photos showing the construction progress on the project, stay tuned for more information about the upcoming traffic shift in February and the weekend road closure scheduled for next summer.