The Mackinac Bridge is a long suspension bridge located in the United States that connects the Lower Peninsula (city of St. Ignace) and the Upper Peninsula (village of Mackinaw City) of Michigan. The bridge is the third longest suspension bridge by total suspension in the world, and is 8,038 m (26,372 ft) long in total with the largest span being 1,158 m (3,800 ft) long (12 largest in the world). The idea for the bridge was raised in the 1880’s as the region continued to be popular for tourism and trade. However, the first attempt at creating a regular crossing was the opening of a ferry service. The ferries were used to transport people and vehicles between the peninsulas. This was not ideal because traffic would sometimes back-up more than 26 km (16 mi) waiting for the ferry and ferry travel during the winter months was sometimes impossible due to ice. The calls for a bridge became stronger and in 1934 the Michigan Legislature created an Authority to explore the possibilities. The route for the bridge was selected by 1940 and plans for the bridge began not long after. Let’s find out who designed and built this impressive bridge.
The American structural engineer David B. Steinman was appointed as the lead designer for the project in January 1953. His design for the Mackinac Bridge was greatly influenced by the failure of the original Tacoma Narrows Bridge. Soon after the failure of that bridge, Steinman had begun to work on the problems with suspension bridges and designed some improvements to prevent another collapse. He incorporated these design changes into the Mackinac Bridge. These ensured that the bridge was capable of withstanding winds up to 240 km/h (150 mph).
By the end of 1953 the estimate for the cost of the project was $95 million with a completion date of 1956. The American Bridge Division of the U.S. Steel Corporation won the $44 million contract to build the steel structure of the bridge and construction began on May 7, 1954. It opened to traffic on schedule and was formally dedicated on June 25, 1958.
Did you know?
Each year a Mackinac Bridge Walk is held and thousands of people, usually led by the Governor, cross the 8 km (5 mi) bridge on foot.