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1-75 / Straits of Mackinac

MDOT Historic Bridge Emmet County I-75 / Straits of Mackinac


County: Emmet

City/Township: Mackinaw City

Location:1-75 / Straits of Mackinac

Year Built: 1958

About this Bridge:
The five-mile stretch of water separating Michigan's two peninsulas, the result of glacial action some twelve thousand years ago, has long served as a major barrier to the movement of people and goods. The three railroads that reached the Straits of Mackinac in the early 1880s, the Michigan Central and the Grand Rapids & Indiana Railway from the south, and the Detroit, Mackinac and Marquette from the north, jointly established the Mackinac Transportation Company in 1881 to operate a railroad car ferry service across the straits. The railroads and their shipping lines developed Mackinac Island into a major vacation destination in the 1880s.

Improved highways along the eastern shores of Michigan's lower peninsula brought increased automobile traffic to the straits region starting in the 1910s. The state of Michigan initiated an automobile ferry service between St. Ignace and Mackinaw City in 1923 and eventually operated eight ferry boats. In peak travel periods, particularly during deer season, five mile backups and delays of four hours or longer became common at the state docks at Mackinaw City and St. Ignace.

With increased public pressure to break this bottleneck, the Michigan legislature established a Mackinac Straits Bridge Authority in 1934, with the power to issue bonds for bridge construction. The bridge authority supported a proposal first developed in 1921 by Charles Evan Fowler, the bridge engineer who had previously promoted a Detroit-Windsor bridge. Fowler's plans called for an island-hopping route from the city of Cheboygan to Bois Blanc, Round, and Mackinac islands, thence to St. Ignace, along a twenty-four-mile route. The Public Works Administration flatly rejected a request for loans and grants to implement this project.

A plan was then drawn up for a direct crossing from Mackinaw City to St. Ignace, but they were again denied funds. In 1940, a plan was submitted for a suspension bridge with a main span of 4600 feet. This design was a larger version of the ill-fated Tacoma Narrows Bridge in Washington State, a structure destroyed by high winds on November 7, 1940. Although the disaster delayed any further action, the activities of 1938-1940 nevertheless produced some important results. The bridge authority conducted a series of soundings and borings across the straits and built a causeway extending out 4200 feet from the St. Ignace shore. The Second World War ended any additional work, and the Legislature abolished the bridge authority in 1947.

William Stewart Woodfill, president of the Grand Hotel on Mackinac Island, almost singlehandedly resuscitated the dream of a bridge across the Straits of Mackinac. Woodfill formed the statewide Mackinac Bridge Citizens Committee in 1949 to lobby for a new bridge authority, which the legislature created in 1950. A panel of three prominent engineers conducted a feasibility study and made recommendations to the bridge authority on the location, structure, and design of the bridge.

The State Highway Department, which had just placed a $4.5 million ferryboat, Vacationland, into service at the straits in January 1952, remained hostile to the bridge plan. In April 1952, the Michigan legislature authorized the bridge authority to issue bonds for the project, choose an engineer, and proceed with construction. The authority selected David B. Steinman as the chief engineer in January 1953 and tried unsuccessfully to sell the bridge bonds in April 1953, but by the end of the year, the authority had sold the $99.8 million in revenue bonds needed to begin construction.

The major construction achievement of 1954 was the erection of the bridge's six principal piers, including those for the two towers, the anchorages, and the backstay spans. Enormous steel caissons were sunk into the mud under the straits and then driven to bedrock. After removing all the mud and loose rock, two reinforced concrete piers, which extended to bedrock, more that 200 feet below the water's surface, were poured. In 1955, the remaining twenty-eight piers were built and the anchorage was completed. The Mackinac Bridge began to take shape in 1956, when the main cables were strung and the twenty-eight truss spans that made up the approaches were built.

The four-year construction effort ended in 1957, with the erection of the main suspension span and paving of the roadway. The new bridge opened to traffic on November 1, 1957, although the contractors did not complete all the work until September 1958. The official bridge dedication ceremonies began on June 25, 1958, with the first "Governor's Walk" across the bridge, and ended four days later.

The annual Mackinac Bridge Walk began as a walking race sanctioned by the International Walkers Association. The first walk, in June 1958, involved only sixty walkers. Later bridge walks took place on Labor Day and the number of participants increased rapidly from about 2500 in 1962 to more than 15,000 in 1966-1968. Since the first "Governor's Walk" at the bridge opening, it has become a mandatory political event for governors and gubernatorial candidates. In 1970, more than 20,000 completed the walk and the numbers reached 70,000 in 1990. The Mackinac Bridge Walk is as much an integral part of Labor Day in Michigan as parades and picnics.

The sheer size and beauty of the Mackinac Straits Bridge still impress first-time viewers. The bridge's total length, 8614 feet, the longest in the world, combined with towers standing 552 feet above the water line, a 155 feet clearance under the bridge, and a total weight of 11,840 tons, is indeed an impressive sight.
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