Sometimes there are hundreds of people; other times, just dozens. But the ritual is always the same.
People gather in the parking lot near the former Grandma's restaurant in Minneapolis just before the 11 o'clock start of the Sidewalk Superintendent Talks, the official name of the regular Saturday tours offered by Flatiron-Manson.
The tours are led by project manager Peter Sanderson. During the walk and talk along the 10th Ave. Bridge, Sanderson explains what the work crews are doing and takes questions.
"The question was 'what is the length of main span, the main bridge that we're building?'" He says.
And Sanderson always has answers.
"Span one is 330 feet, the main span is 504 feet," he says. "Span three, which is this one here, is 250 feet and there's another 90 feet over to the north abutment."
Just a few Saturdays ago, July 5, about 400 people turn out for the tour. It's the biggest crowd to date. Many people were drawn to the construction site because it was a milestone day in the project. The final piece of the northbound section of the new bridge was hoisted into place.
Carol Johnson, an electrical engineer from Rosemount is in the crowd.
"I find it fascinating to see how different systems can be pulled together and coordinated in such an efficient manner," she says. "And I see how the bridge is coming together so quickly. It's just fascinating to see how all the different parts work together toward that goal. And I enjoy watching that."
Mark Holtan of Plymouth is watching the bridge, too. He's been on the Saturday tour before. And he's trying to document the progress. He's taken a series of pictures that started when crews erected the first section of the bridge's roadway.
"I just wish I had more time to come more often because there's some redundancy, but there's a lot of new things," he says. "They tell you what's happened in the past, what's coming in the current week and what they're doing on the site as we're speaking."
Of the thousands of people who have attended the Sidewalk Superintendent Talk, the person who has been there the most often, by far, is Don Heinrich of New Brighton. He's missed only four weeks since the tours started last November.
After a recent tour, he stops for lunch at a nearby restaurant where he reminisces about the early days, when he says the site wasn't very interesting.
"It was not very interesting because when they were doing foundations you could see some equipment working," he says. "They had rigs on both sides of the river, but you couldn't see it like you could later on when they started building the piers and stuff started coming up out of the valley there."
Heinrich has a particular interest in the bridge building. He's a retired MnDOT engineer who used to design and inspect bridges. But he also has another tie to the site. He was one of the first responders from Ramsey Country who was called in when the bridge collapsed last August.
He says there wasn't much he could do by the time he got there. And he says he didn't go back to the site until the construction began on the new bridge.
He says he's been impressed with what he's seen over the last eight months.
"They make a lot of progress every week as much as they're working," he says. "They're working about 20 different sites. There was plenty to see every week. Besides that, it was good exercise, and a lot more fun once I got down to about 2 or 3 layers."
A joke about the cold winter days that Heinrich braved in order to keep up with the construction. The new bridge is set to open by October, two months ahead of schedule. After that Heinrich says he's not sure what he'll do with his Saturday mornings.
"There always seems to be plenty to do around home," he says. "I suppose I'll have to get out the 'to-do' list and see what's on it."