I have driven across the Mackinac Bridge 100’s of times and walked it once.
Once a year the Bridge is open for the Labor Day Walk.
The Mackinac Bridge is currently the third longest suspension bridge in the world. In 1998, the Akashi Kaikyo Bridge in Japan became the longest with a total suspension of 12,826 feet. The Great Belt Bridge in Halsskov-Sprogoe, Denmark, which also opened in 1998, is the second longest suspension bridge in the world with a total suspension of 8,921 feet. The Mackinac Bridge is the longest suspension bridge in the western hemisphere.
Some interesting facts:
Completed on 1957.
Total Length of Bridge….26,444 ft. Close to 5 miles.
Total length Steel Superstructure…19,205 ft.
Length Suspension Bridge including Anchorages…8,614 ft.
Heights of main Towers above Water…552 ft.
Maximum Depth of Water at Midspan…295 ft.
Maximum Depth of Tower piers below Water…210 ft.
Height of roadway above Water at Midspan…199 ft.
Underclearance at Midspan for Ships…155 ft.
Total Length of Wire in main Cables…42,000 miles.
number Wires in each cable…12,580.
Weight of Cables…11,840 Tons.
Diameter of main Cables…24 1/2 inches.
Diameter of each Wire…0,196 inches.
All suspension bridges are designed to move to accommodate wind, change in temperature, and weight. It is possible that the deck at center span could move as much as 35 feet (east or west) due to high winds. This would only happen under severe wind conditions. The deck would not swing or “sway” but rather move slowly in one direction based on the force and direction of the wind. After the wind subsides, the weight of the vehicles crossing would slowly move it back into center position.