Controlled rock blasting planned for Pecos segment of South Mountain Freeway

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Construction Schedule Maps. (Source: ADOT) Construction Schedule Maps. (Source: ADOT)
The South Mountain Freeway will connect the East Valley and the West Valley. (Source: ADOT) The South Mountain Freeway will connect the East Valley and the West Valley. (Source: ADOT)
PHOENIX (ADOT) -

To construct Loop 202 South Mountain Freeway in the Ahwatukee Foothills, crews have been using heavy equipment since April to excavate a hillside near Desert Foothills Parkway.

While this method has been effective thus far at removing rock, Connect 202 Partners, the developer responsible for building the 22-mile-long freeway for the Arizona Department of Transportation, anticipates that controlled rock blasting will be necessary in some locations beginning in August. 

It is currently anticipated controlled blasting will take place in areas west of 24th Street and beyond Desert Foothills Parkway.

Controlled rock blasting uses small amounts of timed charges to break rock into smaller, more manageable pieces. The broken rock will then be removed and used as fill throughout the Pecos Road segment of the freeway. Controlled rock blasting is a standard construction technique used in many areas of the nation for many years without damage to property.

Connect 202 Partners will ensure that ground vibrations from controlled rock blasting using modern techniques comply with local and federal safety and ground vibration standards, which are in place to avoid any impact to structures. Any blasting activities will be in accordance with industry best practices using only proven and safe methods.

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"Controlled rock blasting has been used to shape essential roadways throughout the world, including the initial construction of Pecos Road previously," said Rob Samour, ADOT's senior deputy state engineer for major projects. "Connect 202 Partners has hired an experienced team, including a blasting engineer, blasting consultant and vibration monitoring expert with close to 100 years of combined blasting experience in Arizona and across the United States."

[RELATED: South Mountain Freeway project starting to take shape]

While controlled rock blasting activities will not result in any damage to nearby structures, Connect 202 Partners invited property owners within a half-mile of the area where controlled blasting may be used to participate in a free home survey to document their homes' current structural condition. 

Connect 202 Partners has hired Aimone-Martin Associates, which specializes in blasting and vibration monitoring and has extensive experience working in residential areas in Arizona, to conduct the surveys. The firm also uses seismographs to ensure that ground vibration is within allowable levels and provide a second level of assurance for homeowners. 

[RELATED: Timelapse: First bridge in installation of South Mountain Freeway complete]

To ensure the safety of motorists using Pecos Road and Desert Foothills Parkway, there will be temporary traffic restrictions during blasting activities. Message board signs on Pecos Road and Desert Foothills Parkway will provide advance notice of any traffic restrictions.

The 22-mile freeway, expected to open by late 2019, will provide a long-planned direct link between the East Valley and West Valley and a much-needed alternative to I-10 through downtown Phoenix. Approved by Maricopa County voters in 1985 and again in 2004 as part of a comprehensive regional transportation plan, the South Mountain Freeway will complete the Loop 202 and Loop 101 freeway system in the Valley.

For more information on controlled rock blasting, visit SouthMountainFreeway.com/Pecos.

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