Bridge Designs Congratulations to the following Teams Arch

Bridge Designs Congratulations to the following Teams:

Arch Bridges built first by the Romans to connect Battle Roads Built with Stone Tiber River, Rome In 1781, the first Iron Bridge opened Colebrookdale, England Arch Bridges: Charles River

Beam Bridge: easiest to construct Rarely span more than 250 feet.

The Truss Design The Betsy Ross Bridge, across the Delaware River: Warren Through Truss

Deck Truss with Piers Truss Designs became popular with the development of STEEL (Resisted stretching better than IRON

Scotland's Forth Bridge over the Firth of Forth is a steel cantilever railroad bridge that was designed by Benjamin Baker. It was the longest bridge in the world when it was completed in 1890. Very expensive due to amount of material used.

For medium length spans (those between 500 and 2, 800 Sunshine Skyway bridge Cable Stayed Bridges Zakim Bridge, Boston, MA

Considered a brilliant feat of 19 th-century engineering, the Brooklyn Bridge was a bridge of many firsts. It was the first suspension bridge to use steel for its cable wire. It was the first bridge to use explosives in a dangerous underwater device called a caisson. At the time it was built, the 3, 460 -foot Brooklyn Bridge was also crowned the longest suspension bridge in the world. 1883 3460 ft But the Brooklyn Bridge was plagued with its share of problems. Before construction even began, the bridge's chief engineer, John A. Roebling, died from tetanus. The project was taken over and seen to its completion by his son, Washington Roebling. Three years later, Roebling developed a crippling illness called caisson's disease, (the bends). Brooklyn Bridge: Manhattan and Brooklyn , NY During this time, an unexpected blast wrecked one caisson, a fire damaged another, and a cable snapped from its anchorage and crashed into the river.

1937 4, 200 ft, Suspension Bridge: Golden Gate, San Francisco , CA Can span distances from 2, 000 to 7, 000 feet Strauss used more than one million tons of concrete to build the anchorages -- the massive blocks that grip the bridge's supporting cables. The north pier, which supports the tower, was built easily on a bedrock ledge 20 feet below the water. But on the southern San Francisco side, Strauss had to build his pier in the open ocean, 100 feet below the surface. 1940 7392 Tacoma Narrows Bridge: Tacoma, WA Tacoma Narrows Bridge Collapse Why the collapse?

On the morning of November 7, 1940, the Tacoma Narrows Bridge twisted violently in 42 -mile-per-hour winds and collapsed into the cold waters of the Puget Sound. The disaster -which luckily took no human lives -- shook the engineering community and forever changed the way bridges were built around the world. Engineer Leon Moisseiff had designed the ultimate in slender bridges. The roadway was a mere 39 feet -- only eight teenagers lying head to toe would fit across the bridge! Moisseiff strengthened his narrow bridge with a solid steel girder beneath the roadway. But soon after it opened, the Tacoma Narrows started behaving strangely. Wind caused the bridge to sway back and forth, and it also sent rippling waves along the deck. The Tacoma Narrows tore itself apart only four months later.

Years later, engineers found that the solid girders actually blocked the wind and caused the slender bridge to twist. The twisting bridge fanned the steady wind into a swirling motion, which caused the bridge to twist even more -- and eventually snap in two. The Tacoma Narrows Bridge was replaced in 1950 by a new bridge stiffened with a truss. Rather than blocking the wind, the open truss allowed the wind to blow through the new bridge.