ADOT begins preparing for South Mountain Freeway construction

Preliminarily geotechnical work begins in May to assess subsurface conditions

PHOENIX – As part of the process of moving toward the 2016 start of construction for the Loop 202 South Mountain Freeway, Arizona Department of Transportation crews will begin the preliminarily geotechnical investigation in early May, assessing the condition of soil, rock and depth of groundwater along the freeway alignment.

A geotechnical investigation is designed to provide engineers with data on conditions below the surface, helping to refine construction plans and processes. It will involve soil borings at most future bridge locations – including several at the lengthy Salt River bridge – and rock coring, test pits up to 10 feet deep and other data collection. In all, there are expected to be 49 test borings along the future freeway alignment at depths ranging from 25 to 130 feet below the surface. This equates to about 3,600 feet of soil boring and 870 feet of rock coring.

Materials collected will then be scientifically analyzed to create a profile of subsurface conditions. That data will be used to help refine plans being created by the three development firms that have been selected to submit comprehensive proposals to design, construct and maintain the freeway.

This preliminarily geotechnical work is expected to take about eight weeks to complete, beginning in mid-May; early this month, crews will begin marking locations for testing. There is no impact to residents or the traveling public expected as a result of this preliminarily work, which will occur only during daytime hours.

No work will be conducted within South Mountain Park.

The freeway will be constructed with four lanes in each direction – three general-use lanes and one HOV lane – and modern features that have made Arizona freeways stand apart from other states for a generation, including rubberized asphalt and aesthetics designed in partnership with the community. The $1.9 billion project is expected to take about four years to construct.

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