Suspension Bridges

The main cables in a suspension bridge carry the weight of the deck (roadway) through vertical suspender cables. The main cables transfer this load to the towers and then to the anchorages at each end.

The Tacoma Narrows Bridge ('Galloping Gertie') collapsed on November 7, 1940, due to aeroelastic flutter caused by wind. The bridge's narrow, shallow plate-girder deck was susceptible to wind-induced oscillations that grew catastrophically.

The Akashi Kaikyo Bridge has a main span of 1,991 meters (6,532 feet), making it the world's longest suspension bridge by main span. It connects Kobe to Awaji Island and was completed in 1998.

John Augustus Roebling designed the Brooklyn Bridge, though he died from a tetanus infection before construction began. His son Washington Roebling oversaw construction, which was completed in 1883.

The towers (also called pylons in some contexts) are the tall vertical structures that support the main cables of a suspension bridge. They transmit the cable forces down to the foundations.

The Verrazano-Narrows Bridge connects Staten Island and Brooklyn across the Narrows, the entrance to Upper New York Bay. When it opened in 1964, its 1,298-meter span made it the longest suspension bridge in the world.

Anchorages are massive structures, often made of concrete, at each end of a suspension bridge that secure the main cables. They must resist enormous pulling forces and are typically deeply embedded in rock or heavy enough to resist the cable tension.

The Humber Bridge crosses the Humber Estuary in northeast England, connecting East Riding of Yorkshire to North Lincolnshire. Its main span of 1,410 meters was the world's longest from 1981 until the Akashi Kaikyo Bridge opened.

Cable spinning is the process of building the main cables of a suspension bridge by pulling individual wires back and forth across the span, gradually building up the cable from thousands of parallel wires bundled together.

The Mackinac Bridge ('Mighty Mac') connects Michigan's Upper and Lower Peninsulas across the Straits of Mackinac. Completed in 1957, its total length of 8,038 meters makes it one of the longest suspension bridges in the world.

In a cable-stayed bridge, cables run directly from the towers to the deck in a fan or harp pattern. In a suspension bridge, the main cables drape between towers and vertical suspender cables hang down to support the deck.

The 1915 Canakkale Bridge, spanning the Dardanelles strait in Turkey, has a main span of 2,023 meters, surpassing the Akashi Kaikyo Bridge. The '2023' in the span length commemorates the 100th anniversary of the Turkish Republic.

Joseph Strauss was the chief engineer of the Golden Gate Bridge, which opened in 1937. Charles Ellis and Leon Moisseiff also made significant contributions to the structural design of the bridge.

Workers in the pneumatic caissons of the Brooklyn Bridge suffered from caisson disease (decompression sickness or 'the bends') caused by nitrogen bubbles forming in the blood when returning to normal atmospheric pressure. Washington Roebling himself was permanently disabled by it.

Inca rope bridges used thick cables woven from ichu grass and other plant fibers. Some spanned over 45 meters across deep gorges in the Andes. One such bridge, the Q'eswachaka, is still rebuilt annually using traditional methods.