Mackinac Bridge Named Historic Civil Engineering Landmark

Mackinac Bridge Named Historic Civil Engineering Landmark 150 150 American Bridge

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The Mackinac Bridge was designated a National Historic Civil Engineering Landmark on August 12, 2010, by the American Society of Civil Engineers to recognize and encourage preservation of landmarks, and to promote historical awareness of civil engineering.

American Bridge fabricated and erected the entire 52-span bridge that stretches 18,343’ across the Straits of Mackinac connecting the upper and lower peninsulas of Michigan. The bridge contains 35 deck truss spans, 14 steel plate girder spans, and a 7,400′ three span suspension bridge with a 3,800′ main span. The main cables are 24.5″ in diameter, made from 37 airspun parallel wire strands of 340 wires each and draped over two 552′ tall towers. AB is known for its innovative cable spinning abilities displayed on over 50 other bridges. Additionally, American Bridge fabricated the Mackinaw City and St. Ignace truss and girder approaches to the Mackinac Bridge. This portion of work was 18,188 tons of structural steel alone.

More recently, AB was contracted for the removal of six existing maintenance travelers, removal and replacement of 14,800 linear feet of traveler rail in the suspended spans, replacement of expansion joints in existing truss span traveler rail in 10 locations, and furnishing and erection of eight new maintenance travelers. American Bridge self-fabricated all traveler rails.

The Mackinac Bridge was the longest suspension bridge in the world when completed in 1957. Today it remains the third longest suspension bridge domestically, the 12th longest internationally and the longest suspension bridge between anchorages in the Western Hemisphere.