After a whirlwind of construction this summer in downtown Minneapolis, more work has begun. Only this time there’s a firm Feb. 4 deadline.

Signs of the coming Super Bowl are starting to pop up around downtown, from U.S. Bank Stadium to Nicollet Mall.

On Monday, workers installed the first of what will be five miles of chain-link fencing on concrete slabs around U.S. Bank Stadium, part of a roughly 2½-block security perimeter that will be in place a few days before game day. The barricades measure about 12 feet tall and 3 feet thick at their base.

More of the concrete barriers appeared along 7th Street, and will eventually wrap around a block that includes First Covenant Church Minneapolis and the Erik the Red Bar.

At the western edge of the Commons Park, which was temporarily fenced off, workers with blue lanyards dangling from their necks assembled a large metallic gate, through which visitors will enter to reach the stadium. Several heated tents will house airport-style walk-through detectors, which don’t work as well in cold weather. The western half of the park will remain open to the public, organizers say.

The buildup of the area shows the sheer logistical complexity of hosting the game in an urban setting, said Kyle Chank, the Host Committee’s vice president of operations.

“It’s like a puzzle piece, like Lego blocks, it all has to fit into place,” he said. “On the 15th, you’ll be able to see it — on the 22nd, you’ll be able to feel it.”

More changes will happen over the next few days.

Organizers said the staggered work was done with downtown merchants and residents in mind; many have long worried the festivities surrounding the game, which is expected to attract tens of thousands of out-of-town visitors, will create traffic and parking nightmares on downtown streets, particularly in light of tight security.

“The order of it all has public access in mind,” said Mike Howard, a spokesman for the Super Bowl Host Committee.

While authorities have not released details of where the barriers will go, they have said that in addition to the thousands of uniformed and plainclothes officers patrolling outside the stadium — not to mention snipers perched on nearby rooftops — they will employ physical obstacles to would-be attacks.

Opposite U.S. Bank Stadium, workers had erected two tents in parking lots normally reserved for tailgaters, as red-clad security guards turned away anyone without official credentials. Organizers said the tents will be used to store equipment for the game’s halftime performance, which this year will feature a set by Justin Timberlake.

The city’s Public Works department declined through a spokesman to comment on the work, saying that it was handled by a contractor hired by the NFL.

The pregame preparations are a bit ahead of schedule, Chank said.

With temperatures in the early part of the week clawing back into the 40s, organizers saw an opening to start putting up some of the barrier, he said. But a cold snap could halt work at the site.

“If we really do get 9-10 inches of snow tomorrow then you won’t see much of anything in the next couple of days,” Chank said, adding that a lot will also hinge on how far the Vikings advance in the playoffs.

Street closures will follow in the coming days, organizers say. Chicago Avenue, which runs alongside the stadium, is already closed to through traffic, and 6th and 4th streets will shut down the week of the game.

Over at a staging area off Washington Avenue that is being used to store fencing and other equipment, semitrailers this week began hauling in pieces of the American Birkebeiner International Bridge, which will come to Nicollet Mall Saturday. The 200-foot bridge has never been erected outside Hayward, Wis, where it is assembled once a year for the American Birkebeiner, the nation’s largest cross-country ski race.

At the staging area, every piece will be inspected and accounted for, before the bridge is built on the Mall over 9th Street during the 10-day extravaganza known as Super Bowl Live, Chank said. The NFL will take over the street on Saturday and construction of the “Verizon Up Stage at Ice Mountain,” at the corner of 8th Street and Nicollet Mall, will start next Monday.

For some downtown locals, the work going on at Commons park was only a taste of what is to come.

“It is a little inconvenient because we’re right here,” said Nate, who asked that only his first name be used, as he stood outside one of the Wells Fargo towers, pulling on a cigarette.

He said that he and his colleague had received regular e-mails updating them on announced street closures and other disruptions, but “not a whole lot of” other information. A few workers who catch the bus at work had been told that their regular stops were being moved, he said.

Another e-mail encouraged employees to leave the building by 3 p.m. during Super Bowl week in order to avoid getting stuck in traffic, he said.