Here Comes the Sun: Ciminelli's SolarCity Project
Using the old plans and overlays from Google maps, the contractor began pre-digging the site. “We wanted to get an early start so that when the gun went off, we’d be ready,” Ciminelli says. “We wanted to get out in front of the trades.”
When the building was demolished, a lot of the old equipment and infrastructure was either buried in the debris or thrown into what was left of the old foundation.
Remains of the steel factory that were unearthed included nearly two tons of old railroad ties, steel ingots, box cars used for transporting raw ore to the factory and a 15-ft-tall turbine. “Every shovel was a new adventure,” Ciminelli says.
When the debris was cleared, LPCiminelli began punching holes in the site every 20 ft, using a mining drill with teeth capable of chewing through concrete and a lot of metal.
The holes provided a home for the 6,000 or so 14-in.-dia steel pipe pilings that the contractor sank into the ground. Some of the pilings had to be sunk to 70 ft or more before they found bedrock.
The site, on a riverbank and about one mile from the shore of Lake Erie, is glacial till. The ground is sandy and silty, and there was no telling what still might be below grade that might cause differential settlement, Ciminelli says. “Digging deeper could be a double entendre on this project.”
The pilings, topped with clusters of pile caps, provided a solid support for the massive slab that would become the foundation of the factory floor.
The pipe piling also provided flexibility, which was important since the design for the manufacturing equipment was being done concurrently with the construction work. “We could quickly change how the pilings were used to adapt to the shifting equipment design,” says Tom Birdsey, president and CEO of EYP Architecture & Engineering, one of the design firms working on the project.
As the pilings were sunk, other crews came along behind the piling workers to pour the concrete slab. Under the factory’s office area, the slab is 8 in. thick; in the production areas, it is 12 in. thick; and it jumps to 19 in. thick in the utility area that will house the plant’s heavy equipment.