South Mountain Freeway subsurface testing to start in West Valley

PHOENIX – After beginning work along the southern alignment of the future Loop 202 South Mountain Freeway, crews next week will start assessing soil conditions and the depth of groundwater along the western alignment.

On Monday, June 27, workers using drills will start on the embankment slope along eastbound Interstate 10 from the 59th Avenue on-ramp to the 51st Avenue off-ramp.

There will be a shoulder closure along the eastbound I-10 ramps between 59th and 51st avenues from 9 a.m. to 5 p.m. on weekdays until work is completed. While this isn’t expected to have much effect on traffic, motorists should be alert for workers.

Assessing underground conditions will help engineers design the freeway’s pavement, bridges, walls and drainage structures. The latest work is where the South Mountain Freeway’s I-10 connecting ramps, frontage roads and retaining walls will be located.

Information on the soil, including its type, density, moisture content and strength, is essential prior to building any roadway and ensures that roads and bridges are properly designed and maintained to ensure longevity.

Throughout the entire 22-mile-long freeway corridor, workers will drill holes, called borings, and dig test pits up to 10 feet deep along the roadway alignment, and at 45 future bridge and retaining wall locations. Materials collected will be analyzed to create a profile of what lies beneath the surface.

There are expected to be 720 borings to depths of 5 to 175 feet. In all, there will be about 29,000 feet of drilling and 800 feet of backhoe pit excavation.

The South Mountain Freeway, which will run east and west along Pecos Road, and north and south near 59th Avenue, will connect with Interstate 10 at each end. When opened to traffic by late 2019, it will complete the Loop 101 and Loop 202 system, create a long-planned direct link between the East Valley and West Valley, and provide an alternative to I-10 through downtown Phoenix.

Preparing for the start of construction, ADOT also is conducting preliminary engineering, addressing cultural resources in the right of way, acquiring and preparing properties, and relocating utilities. ADOT received final federal clearance to move forward with the project in spring 2015.

For more information, visit azdot.gov/SouthMountainFreeway.