The project included the construction of six solar power canopy carports within the parking lot of an existing commercial facility and ten rows of ground mounted photovoltaic solar arrays within a previously undeveloped portion of the property. Northeast Geotechnical performed design phase geotechnical engineering studies for the 1.6 MW system that included coordination and logging of soil test borings, laboratory testing on selected soil samples, and preparation of recommendations for use in foundation design and earthwork construction associated with the solar structures and equipment slabs.
Subsurface conditions across the site were variable and included areas of relatively deep, loose existing fill materials, organic surficial soils, and natural deposits of silt, sand, and gravel. Given the varying subsurface conditions, Northeast Geotechnical provided multiple foundation design recommendations including pier-and-pad foundations and drilled shafts for the carport structures, and driven steel posts for the ground-mounted arrays.
Northeast Geotechnical provided value engineering to the design team by evaluating frost susceptibility at a site-specific level, thus allowing for a greater frictional capacity of drilled shafts and driven steel post foundations. This allowed for shorter foundations to be used, providing cost savings to the owner.
