Giant concrete walls, three stories high and 30 feet wide, cut slowly through the air Tuesday morning, hoisted by a giant crane that moved the 204,000-pound slabs as easily as a child lifts the panels of a cardboard clubhouse.
In just under 30 minutes, construction crews guided, positioned and fastened each wall in a speedy process that belied the months of preparation that came before.
By Thursday, the new Sutter Santa Rosa Regional Hospital campus will have its second key facility — an 80,000-square-foot medical office building.
Sutter Medical Center Tilt Up
"A lot goes into this before today," said Jodie Clay, project manager for the construction company Swinerton Builders. "There's kind of nothing, nothing, nothing and then all of a sudden you have a building."
The construction process, known as a tilt-up, is common among warehouses and big-box structures such as Wal-Mart, Target and Friedman's Home Improvement. It's not so common for constructing multi-level medical office buildings, said Jim Kobayashi, development manager for Hammes Company, a health care construction developer.
The tilt-up process is more affordable than steel-frame building and shaves one or two months off the construction timeline.
"We and a lot of our competitors are going this way to keep construction costs down and keep the rental rates within the market," said Kobayashi.
Unlike prefabricated construction, tilt-up wall sections are "poured in place," where casting frames and rebar are laid on a flat surface and, in this case, 10- to 12-inch thick concrete is poured into the frames to form the walls. It takes about seven days for the concrete to cure.
After the walls go up, an interior skeleton of steel columns and beams will be built inside the perimeter of the building. Then floors and a roof will be installed.
"So that by May, the interior construction begins and the building will be done by August," Kobayashi said.