Securing the Slab
When the debris was cleared, the contractor 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. diameter 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 said.
The pilings, topped with clusters of pile caps, provides 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,” Tom Birdsey, president and CEO of EYP Architecture & Engineering, said.
As the pilings were sunk, other crews came along behind the piling workers, pouring concrete slab. Under the factory’s office area, the slab is 8 in. thick; in the production areas, a foot thick, and it’s 19 in. thick in the utility area that will house the plant’s heavy equipment.
The utility area speaks to the specific high-tech requirements of a solar panel factory. The utility building will occupy 250,000 sq ft and will be “the brains and the guts” of the factory, Ciminelli says.
It will have an electrical substation, a boiler plant, gas distribution center to move the 16 different industrial gases required in making solar panels to the proper place on the production lines. It will also house a water treatment plant.
The water plant will have its own $9-million water purification system capable of providing the factory with five different levels of water purity, ranging from tap water to water that has as little as 1 micron of impurity.
