Mackinac Bridge Authority

Spanning the Straits of Mackinac since 1957

What is the width of the roadway?

Posted on October 14th, 2016
Answer:
The width of the roadway is 54 feet. The outside lanes are 12 feet wide (2), the inside lanes are 11 feet wide (2), the center mall is 2 feet wide, and the catwalk, curb and rail width is 3 feet on each side – totaling 54 feet. The stiffening truss width in the suspended span is 68 feet wide making it wider than th… Read More

How much does the Mackinac Bridge “swing” or “sway” in the wind?

Posted on October 14th, 2016
Answer:
All suspension bridges are designed to move to accommodate wind, change in temperature, and weight. The deck would not swing or “sway” but rather move slowly in one direction based on the force and direction of the wind. It is possible that the deck at center span could move as much as 35 feet (east… Read More

How much weight can the Mackinac Bridge support?

Posted on October 14th, 2016
Answer:
The steel superstructure will support one ton per lineal foot per roadway (northbound or southbound). The length of the steel superstructure is 19,243 feet. Each direction will, therefore, support 19,243 tons. The answer is 38,486 tons (2 x 19,243 tons).… Read More

Is the Mackinac Bridge still the longest suspension bridge in the world?

Posted on October 14th, 2016
Answer: Although the Mackinac Bridge remained one of the four longest suspension bridges for more than 40 years, several bridges built since 1998 have surpassed it. Suspension bridges are commonly measured by main span length which is the distance between towers. By this ranking, the Mackinac Bridge is currently… Read More

What is the height of the roadway above the water?

Posted on October 14th, 2016
Answer:
The height of the roadway at mid-span is approximately 200 feet above water level. The vertical clearance at normal temperature is 155 feet at the center of the main suspension span and 135 feet at the boundaries of the 3,000 ft. navigation channel.… Read More

Where is the Mackinac Bridge located?

Posted on October 14th, 2016
Answer:
The Mackinac Bridge is located in northern Michigan at the Straits of Mackinac. The bridge connects Michigan’s upper and lower peninsulas. Mackinaw City is located at the south end of the bridge. St. Ignace is located at the north end of the Mackinac Bridge.… Read More

What type of expansion joints are used on the Mackinac Bridge? How many?

Posted on October 14th, 2016
Answer:
There are two large finger joints at the towers to accommodate all the expansion of the suspended spans. There are 11 smaller finger joints and 5 sliding joints across the Mackinac Bridge. In addition, there are 13 expansion joints for the south viaduct spans – one for each of these simple spans. This ad… Read More
Mackinac Bridge Authority
N 415 I-75 St Ignace, MI 49781 (906) 643-7600
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