Everyone has heard of the Great Lakes region in North America. It has 5 freshwater lakes, all of them among the largest lakes in the world: if you look at a map of the area between the United States of America and Canada, you get the impression that it is sea. The largest of these lakes is Lake Superior, which is also the furthest north. The second largest is Lake Huron, which is home to the largest lake island in the world, Manitoulin; connected with this lake is Lake Michigan, which is entirely within US territory. And then there is Lake Erie and Lake Ontario. As we said above, the two lakes Michigan and Huron are connected: they are on the same level, and what links them is not a river, but a strait, so that in fact it makes the two lakes into one enormous lake. The strait in question is called Mackinac, a name that the US settlers took from the indigenous word for the area, that is, Mitchimakinak. During the progressive industrialization of the state of Michigan, this lake was regularly crossed by ferries, connecting the 8 kilometres of water between the cities of St. Ignace and Mackinaw City, respectively north and south of the strait. What changed things and made travel much easier, was the construction of the ultra-long Mackinac Bridge in the 1950s, a suspension bridge that has connected the upper and lower peninsulas of Michigan ever since: we take a look at the history, the record-breaking statistics and the most interesting data about this very long bridge. We should point out from the start that it is still the longest bridge in the Western hemisphere in terms of suspended length today.
The history of the construction of the Mackinac Bridge
The inhabitants of Michigan call this long suspension bridge the Big Mac or Mighty Mac. As we have already noted, this road connection was constructed in the 1950s, but there had been talk about a bridge over the Mackinac strait for a long time before that; the closeness of the two peninsulas at the strait, where the two large lakes touch, seemed to be a natural invitation to build a bridge. However, the enormous distance between the two coasts remained a technical obstacle that proved impossible to overcome for many decades. Thus, ferries continued to be used in the 19th century to transport the wood and minerals extracted in the area. What changed things, at least on paper, was the opening of Brooklyn Bridge, in 1883: the following year, an entrepreneur from St. Ignace publicly proposed the construction of a similar bridge in the strait, to connect the two peninsulas. This sparked a debate about the possibility of connecting the two coasts, with some suggesting the construction of a tunnel rather than a suspension bridge. Such a connection was very much desired by the tourist operators in the area, who were conscious of the high numbers of visitors arriving on the shores of the lake to enjoy the various attractions on offer, starting with the recent Mackinac National Park, established in 1875. It was actually a director of the Grand Hotel on Mackinac Island who suggested the construction of a bridge like that over the Firth of Forth, which was under construction at that very time in Scotland. All these were mere suggestions, however, and the issue was set aside for many years.
The need for a connection between the two shores of the lake was revived again in the 1920s, and various different proposals were put forward during this period, including the construction of a floating tunnel and the construction of a series of bridges to connect the two peninsulas, making use of the islands present in the strait. To respond to the growing demand for connections, the government set up a passenger ferry service, but within 5 years this was already proving inadequate to meet the transport needs for the peak numbers of visitors. That is why in 1934, a commission for the construction of a bridge was finally set up, which proposed the construction of a single suspension bridge between the two peninsulas, at a cost not exceeding 32 million dollars. The first soil analyses and excavations were carried out in the late 1930s: however, everything was then interrupted by the Second World War. The commission was cancelled, and was re-established in 1952. The actual works on the construction of the Mackinac Bridge finally began in 1954, to designs by the engineer David B. Steinman. More specifically, the works took place between 8 May 1954 and 1 November 1957, the day of the official opening of the bridge; at 8,038 metres long, the bridge linked the two shores of the lake without touching any of the islands in the strait.
The Mackinac Bridge in the rankings of the longest bridges in the world
For a long time, the Mackinac Bridge was one of the 4 longest suspension bridges in the world. However, from 1998 onwards, various bridges constructed in the East have pushed it down the rankings to 24th position, measuring the spans between the two towers. It should be pointed out that the spans leading up to the two towers, at either end of the Mackinac Bridge, are also very long: for this reason the Mackinac bridge is still one of the 5 longest bridges in the world, and is still the longest suspension bridge in the Western hemisphere. The suspended distance between the two towers is 1,158 metres, however.
As for the height, the towers rise 168.25 metres above the water, with the road in the central tract running 61 metres above the lake. The construction of the Mackinac Bridge required 67,592 kilometres of cable, with the main cables having a diameter of 62 centimetres.
