An Iconic Engineering Marvel

On November 1, 1957, the Mackinac Bridge officially opened to traffic, marking a monumental achievement in engineering despite the many challenges posed by the turbulent Straits of Mackinac. Spanning an impressive 26,372 feet, this iconic bridge connects Michigan’s Upper and Lower Peninsulas and stands as a testament to human ingenuity and determination.

The Specs

  • Its total length is 5 miles, or 26,372 feet.
  • The main towers rise 552 feet above the water.
  • The roadway sits 199 feet above the water at midspan.
  • There are 42,000 miles of wire in the main cables.
  • The cables weigh 11,840 tons.
  • The total weight of the bridge is 1,024,500 tons.
  • This includes 931,000 tons of concrete.
  • It contains 4,851,700 steel rivets.
  • The bridge also has 1,016,600 steel bolts.
  • The bridge can support 38,486 tons.

The Construction

  • Construction commenced on May 7, 1954.
  • A total of 4,000 engineering drawings were created for the bridge.
  • There were 85,000 blueprints involved in its construction.
  • The length of the main span is 3,800 feet.
  • The width of the bridge’s roadway is 54 feet.
  • The outside lanes measure 12 feet wide, and the inside lanes are 11 feet wide.
  • The center mall is 2 feet wide, and the catwalk, curb, and rail width is 3 feet on each side.
  • Suspension bridges like the Mackinac Bridge are designed to move, accommodating wind, temperature changes, and weight; the deck at midspan can shift as much as 35 feet due to high winds.
  • Construction costs totaled $99.8 million.

The Crew

  • 3,500 workers were employed at the bridge site.
  • An additional 7,500 workers were employed at quarries, shops, and mills.
  • 305 engineers worked on the project.
  • At the time, it boasted the largest bridge construction fleet ever assembled.
  • D.B. Steinman was selected as the bridge’s engineer in January 1953.

The Tragedies

  • One man died in a diving accident, while another fell in a caisson while welding.
  • One man drowned after falling into the water.
  • Two men fell from a temporary catwalk near the north tower.
  • On August 7, 1997, a bridge painter fell from his platform and drowned.

Painting the Bridge

  • A $6.3-million, 21-month painting project began in April 2017.
  • The towers were covered in zinc-based paint during renovations.
  • This project marks the first time the towers were stripped to bare metal since the bridge’s construction.
  • Lead paint was removed, contained, and shipped as part of the work.

Important Dates

  • The bridge opened to traffic on November 1, 1957.
  • The 50 millionth crossing occurred on September 25, 1984.
  • The 100 millionth crossing took place on June 25, 1998.
  • D.B. Steinman was selected as the bridge’s engineer in January 1953.

The Ranking

  • The Mackinac Bridge is the seventh-longest suspension bridge in the world.
  • Its main span is the 19th longest globally.
  • It remains the longest suspension bridge in the Western Hemisphere.
  • The bridge ranked 64th among the top 100 U.S. travel destinations on Instagram in a 2017 TravelBird survey.

Crossing the Mighty Mac

  • Tolls are $2 per axle or $4 per passenger vehicle.
  • Vehicles not fitting passenger characteristics pay $5 per axle.
  • Pre-paid toll accounts called Mac Pass are available.
  • If driving across the bridge feels daunting, the Drivers Assistance Program offers free drivers available 24/7.
  • Transportation services are provided for pedestrians, cyclists, snowmobilers, and ATVs.
  • The first toll-paying vehicle was a 1950s Chevrolet station wagon.
  • July 2016 saw the most crossings, with 604,165 recorded.
  • More than four million vehicles crossed the bridge in 2016.
  • The Mackinac Bridge Walk has been held annually since 1958.

Media

  • The bridge featured in an episode of “Modern Marvels” in 2003.
  • It also appeared on an episode of “Dirty Jobs.”

Miscellaneous Facts

  • In 2017, Michiganders could purchase 60-year-old grated metal pieces of the original bridge during an online auction.
  • Temporary closures have occurred due to falling ice, blowing snow, and high winds.
  • An ad agency chose the bridge’s colors, initially featured in an advertisement for a client supplying engines and equipment for its construction.
  • The bridge is prominently displayed on Michigan license plate designs.

The Mackinac Bridge not only transformed travel between Michigan’s peninsulas but also became an emblem of state pride and resilience. Its engineering brilliance continues to fascinate and draw visitors from around the globe.

Learn more about the rich history of the Eastern Upper Peninsula.