Tukwila Urban Access

The Tukwila Urban Access initiative aimed to reconfigure Southcenter Parkway between Strander Boulevard and the northbound I-5 off-ramp, specifically the section leading to the main mall entrance. Various components were included in the construction, such as mechanically stabilized earth (MSE) walls, concrete masonry unit (CMU) block walls, precast stem walls, cast-in-place walls, soldier pile walls, and soldier pile abutment walls, all adorned with a shotcrete fascia. Additionally, the project team constructed a new bridge. The project featured various elements, such as roadway and pedestrian lighting, decorative handrails, stormwater systems, and utilities.

To address congestion and improve access to and from I-5, the project involved lowering the Southcenter Parkway southbound lanes by approximately 20 feet and erecting a new bridge spanning Klickitat Drive over these lanes. Two new northbound lanes were built with a retained earth wall embankment. The project also included the installation of four new signalized intersections strategically located at the Double Tree entrance, Strander Boulevard, Klickitat Drive, and the Southcenter Mall entrance.

Acknowledging the need to minimize disruptions to traffic, the project adhered to an accelerated schedule, initiating road closures and reopening roads and off-ramps to their final configurations well ahead of the initial schedule. The construction approach involved building the bridge and approach moment slabs on grade, avoiding the use of falsework. Subsequently, excavation of the southbound lanes, along with utility installation, precast wall panels, lighting systems, signs, and final pavement, was executed from underneath.

In addition to the core objectives, Atkinson proposed a Cost Reduction Incentive Proposal (CRIP). Collaborative efforts with stakeholders led to the redesign of the drainage system, reducing disturbed ground and generating cost savings for the project owner.