The arch bridge works by distributing compression through its semicircular form into a horizontal thrust restrained by its abutments, or legs. Longer bridges often consist of a series of arches, as the greater the curvature, the more tension on the bridge's underside. If the arch is too big, tension overcomes the natural strength of the semicircular design.Know More
Though there are architectural variations to arch bridges, the basic structure remains the same. In the past, arch bridges were often made of stones, with a keystone in the middle that bore the bulk of the weight. The more weight the bridge bore, the stronger its structure became. Due to their inherent weight, these bridges required extremely sturdy foundations. Most modern arch bridges are made of reinforced concrete.
Arch bridges are durable. The oldest standing arch bridge in the world, the Arkadiko Bridge on the Peloponnese in Greece, was built around 1300 B.C. but is still used today. Many Roman bridges and aqueducts, built in segmented arches, still stand. Medieval builders improved the span and height of arch bridges by modifying the thickness of the arch barrels. Modern arch bridges include the Lupu Bridge in Shanghai, which is more than 1,800 feet long, and the New River Gorge Bridge in West Virginia, which is 1,700 feet long.Learn more about Architecture
Videos on bridge building can be found on a number of websites. Ron Hazelton Home Improvement Online (RonHazenton.com) has a video on how to build a wooden foot bridge. The website lays out detailed instructions in several steps, each accompanied by a separate video. The resulting laminated bridge spans 12 feet, rests on heavy block piers and has side rails and decking.Full Answer >
A truss bridge is the strongest kind of bridge. It combines materials in a simple and efficient way that reduces and spreads out loads over a large area. They flex less than other kinds of bridges and provide greater stability even in extreme weather or traffic.Full Answer >
As of 2014, the largest beam bridge in the world is the Lake Pontchartrain Causeway in Louisiana. Northbound, the bridge span is 23.87 miles long while the southbound span is 23.86 miles long.Full Answer >
The busiest bridge in the world is the George Washington Bridge. It connects Fort Lee, Bergen County, New Jersey to the Washington Heights neighborhood of Manhattan in New York City. More than 100,000,000 vehicles cross it every year.Full Answer >