ST. ALBANS CITY — Extended length tractor-trailer rigs are making numerous trips daily carrying pre-fabricated concrete slabs through St. Albans City streets. The immense concrete slabs are being used to construct a new five-level parking garage within the former downtown core parking lot.

All of the slabs will be in place within six weeks, according to Jim Hoag, who is overseeing the construction for the ReArch Company.

ReArch, which will own a new state office building on Federal Street, is managing the construction of both buildings. The parking garage will serve both the public and the new state office building.

The state office building is four stories and constructing two large buildings right next to each other in the heart of a small city is a challenge.

“Everything is minute-by-minute coordination,” said Hoag. All deliveries of construction materials must be carefully coordinated, and many require temporarily stopping traffic on neighboring streets. “You’ve got to keep traffic flowing,” he added.

The four-story state office building project has 70 construction workers and seven subcontractors with workspace confined to the building itself and a 30-foot roadway around it. “It’s been a challenge,” said Steve Rowe, the supervisor for the office building project.

“We’ve absolutely got to be good neighbors while we build,” said Rowe.

A 300-ton crane, rising 230 feet into the air, is being used to carefully lower the concrete slabs and columns into place. A three-foot deep reinforced pad had to be constructed to support the crane.

Steel rebar is built into each column and slab. “The columns are just stuffed right full of them,” said Hoag. Each column weighs 125 tons.

The slabs on which cars will drive and park weigh 80,000 pounds each and 80-foot trailers are needed to bring them onto the site. Workers are dispatched to control traffic at either end of the route, explained Hoag.

The slabs can hold 4,000 to 5,000 pounds per square inch, he said.

The main structure of the garage will be completed in five to six weeks, said Hoag. Then work will begin on the elevator towers and stairways. In addition, both interior and exterior caulking will need to be done. The entire garage should be complete in November.

Before work could begin, soils contaminated from fires that have occurred in St. Albans, and the site’s years of use as a parking lot had to be removed. Some of the soils are being encapsulated and reused at the site, said Hoag. Otherwise, the soils have to be hauled to landfills. “We saved them as much as we possibly could,” said Hoag.

The cost for the garage and a new traffic light at the corner of Federal and Lake streets is approximately $13 million. There will be roughly 270 parking spaces in and immediately around the garage with 170 slated for the use by staff and visitors to the new state office building.

All four floors of the state office building are being constructed simultaneously, and the top floor will be completed first, explained Rowe.

Mechanical systems are currently being installed while the masonry work is being done on the outside of the building. In 90 days the masonry should be complete, and exterior work will shift to landscaping and paving, explained Rowe.

The building is being kept air and watertight at this point, and workers are not allowed to smoke inside it. “It’s not good for the building,” said Rowe.