Composite Underpinning System in Harsh Winter Conditions-PPT Presentation

PPT Presentation

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The Somerville High School underpinning project in Somerville, Massachusetts, faced significant site and weather challenges. Construction was originally scheduled to begin in July 2018 and finish on March 25, 2019. Work was delayed after crews discovered a dry rubble-stone foundation at the B-Wing and asbestos in the soil, each adding an estimated three months. Production began on December 20, 2018, and the project was completed on April 4, 2019.<br /><br />The system used minipiles drilled through existing foundations and connected to footings with grout. Soil nails provided earth retention. The ground included glacial till and silty sand with gravel, which was strong when undisturbed but could soften when reworked and exposed to water. Winter conditions—including low temperatures, wind, and limited landfill availability—also slowed off-site soil removal.<br /><br />Engineers proof-tested 5% of production soil nails and monitored movement through surveys and instrumentation. Measurements showed limited movement, including less than 1/8 inch in the soldier piles, providing reassurance that the system performed as intended.

Keywords

Somerville High School

underpinning project

Somerville Massachusetts

minipiles

soil nails

dry rubble-stone foundation

asbestos contamination

glacial till

winter construction delays

instrumentation monitoring