Mackinac Bridge face-lift draws another national honor
Tower painting project engineering latest to earn acclaim
The "Mighty Mac" was honored recently for a multi-million-dollar project that's giving the five-mile long, 63-year-old span a fresh look.
The Mackinac Bridge Authority announced this month the tower painting project has won yet another national award — its fourth recently — this time from the National Council of Structural Engineers.
Ruby+Associates of Bingham Farms was named the Outstanding Project Winner in the Other Structures category of the council's Excellence in Structural Engineering Awards. The firm designed the movable painting platforms being used in the Mackinac Bridge's back-to-back two-year painting projects for the span's towers, which are 552 feet tall.
"The judges were impressed by the solutions provided for the unique challenges on this project," said Carrie Johnson, chair of the council's awards committee. "The engineers were tasked with creating a painting platform. This was a two-story, movable steel and aluminum structure capable of sustaining 100 mph winds. The solution eliminated the need for almost 400 feet of scaffolding."
The scaffolding was fabricated by Moran Iron Works of Onaway, in northern lower Michigan.
Installation and removal of the platforms has required brief closures during the overnight and early morning hours on several occasions.
The painting is part of a substantial, long-term preservation effort scheduled for the next several years, said Kimberly Nowack, executive secretary of the bridge authority. Until the late 1970s, the authority hired contractors to spot paint the towers as needed.
"The project that is going on now, for only the south tower, is the last in a long series of separate painting projects that have gone on for many years, since the '90s," Nowack said. "The contractor is taking off the original lead-based paint, and this is the first time the towers have had all the paint totally removed and replaced, although there have been many overcoats through the years. There is no color change."
The zinc-based paint, being applied by Seaway Painting of Livonia, is an "iconic ivory" and is expected to last at least 35 years with periodic maintenance, Nowack said.
Seaway is required to contain 100% percent of the original paint as it is removed and ship it to an appropriate landfill.
Nowack said the south tower project, expected to be completed in early 2021 at a cost of just under $6.5 million, requires daily and overnight lane closures during times of lighter traffic.
The contract to repaint the north tower, which was completed in 2018, was just less than $6.3 million.
Original construction on the bridge, spanning Michigan's Upper and Lower Peninsulas between St. Ignace and Mackinaw City, began in May 1954 and the first traffic traversed the structure in November 1957. The bridge, the fifth-largest in the world, has launched millions of vacation photographs and never ceases to thrill both long-time residents or visitors viewing it for the first time.
The 54-foot wide bridge is 200 feet above water level and has a total weight of 1,024,500 tons.
The bridge celebrated its 100 millionth crossing in 1998. In October 2020, the authority recorded 405,702 vehicles had crossed the bridge, compared with 399,826 in 2019.
Nowack said the numerous honors, including the recent award to Ruby+Associates, "recognize the engineering knowledge and problem-solving creativity of the firms involved, evident from the excellent job they've done repainting the Mackinac Bridge towers."
Among other awards:
--In March, Ruby+Associates received one of five Engineering Honorable Conceptor Awards from the American Council of Engineering Companies of Michigan at the association's annual Engineering and Surveying Excellence Awards Gala.
--Earlier this year, representatives of Seaway accepted the E. Crone Knoy Award from the Society for Protective Coatings, an industry group focused on protecting and preserving concrete, steel, and other industrial and marine structures.
--Last summer at the Structural Engineers Association of Illinois 2019 Excellence in Structural Engineering Annual Awards, Ruby+Associates took home the Best Neighboring State Project Award for the platforms used in the painting project.