London’s Bridges Are Not Falling By Ricky Smetana

Basic Bridge Types Girder Truss Rigid Frame Arch Cable Stayed Suspension

Girder A girder bridge is perhaps the most common and most basic bridge. Typical Span Lengths: 10m - 200m World's Longest: Ponte Costa e Silva, Brazil Total Length: 700m Center Span: 300m

Truss The truss is a simple skeletal structure. Trusses are comprised of many small beams that together can support a large amount of weight and span great distances. The most representative trusses are the Warren truss, the Pratt truss, and the Howe truss. Typical Span Lengths: 40m - 500m World's Longest: Pont de Quebec Total Length: 863m Center Span: 549m

Rigid Frame A rigid frame bridge is one in which the piers and girder are one solid structure. Though there are many possible shapes, the styles used almost exclusively these days are the pi-shaped frame, the batter post frame, and the V shaped frame.

Arch Arches use a curved structure which provides a high resistance to bending forces. arches can only be used where the ground or foundation is solid and stable. Structurally there are four basic arch types: hinge-less, two- hinged, three hinged and tied arches. Typical Span Lengths: 40m - 150m World's Longest: New River Gorge Bridge, U.S.A. Total Length: 924m Center Span: 518m

Cable Stayed A typical cable stayed bridge is a continuous girder with one or more towers erected above piers in the middle of the span. From these towers, cables stretch down diagonally (usually to both sides) and support the girder. Though only a few cables are strong enough to support the entire bridge, their flexibility makes them weak to a force we rarely consider: the wind. Typical towers used are single, double, portal, or even A-shaped towers Cable arrangements also vary greatly. Some typical varieties are mono, harp, fan, and star arrangements Typical Span Lengths: 110m - 480m World's Longest: Tatara Bridge, Japan Total Length: 1,480m Center Span: 890m

Suspension The suspension bridge allows for the longest spans. A typical suspension bridge is a continuous girder with one or more towers erected above piers in the middle of the span. The girder itself it usually a truss or box girder though in shorter spans, plate girders are not uncommon. At both ends of the bridge large anchors or counter weights are placed to hold the ends of the cables. The cables pass over a special structure known as a saddle. The saddle allows the cables to slide as loads pull from one side or the other and to smoothly transfer the load from the cables to the tower. Typical Span Lengths: 70m - 1,000m+ World's Longest: Akashi Kaikyo Bridge, Japan Total Length: 3,911m Center Span: 1,991m

Movie with Bridges: Jumping Off Bridges -Inspired by invincible friendships, junior high journal entries, heart breaking crushes and the complexities of losing loved ones, jumping off bridges follows a carefree, adventurous group of four best friends deep in the trenches of adolescence. -Throughout the movie the characters had jumped off several different types of bridges. -And yes the movie is revolved around bridges

Bridge in Book The book switches between three main protagonists, John Orr, Alex, and the Barbarian, who turn out to be different levels of the psyche of a man who is in a coma after crashing his car on the Forth Road Bridge. By Iain Banks

Bridge Disasters Tay Rail Bridge: girder bridge; Dundee, United Kingdom; Faulty design, construction and maintenance, collapsed because of structural deterioration and wind load exceeding estimate Bridge unusable, girders partly reused, train damaged Upper Steel Arch Bridge Also known as Honeymoon Bridge and Falls View Bridge Niagara Falls, NY– Niagara Falls, ON; U.S. and Canada Steel arch road bridge Ice jam in gorge pushed bridge off foundations Bridge completely destroyed Replaced in 1941 by the Rainbow Bridge.

More Bridge Disasters Tacoma Narrows Bridge Tacoma, WA U.S. Road bridge, cable suspension with plate girder deck Aerodynamically poor form resulted in aeroelastic flutter. Bridge partially destroyed, one car lost, and one dog killed Became known as "Galloping Gertie", in the first 4 months after opening up until its collapse under aeroelastic flutter.. Since that time all new bridges have been modeled in wind tunnels. Rebuilt in 1950; parallel span opened in 2007.

Famous Bridges Akashi-Kaikyo Connecting Kobe on the mainland with Awaji on Awaji Island (Japan) three-span cable-stayed bridge some 3910 meters in total length with a center span of 1990 meters. The bridge has a wind-proof and earthquake-resistant construction, withstanding winds up to 80 meters per second and earthquakes reaching 8.5 on the Richter scale. Bayonne New Jersey/New York, USA Steel Arch Awarded the prize for Most Beautiful Steel Arch Bridge of 1931 be the American Institute of steel construction. span: 1,652 feet

More Famous Bridges Sydney Harbor Steel arch Sydney, Australia The world's third largest steel arch bridge. span: 1,650 feet

The Physics Involved Stress: is produced by forces Strain: as a load as applied to an object, that object deforms just the right amount to produce the required opposing force. Such a change, expressed as a fraction of the original size. Tension: act or process of stretching something tight. Compression: act or process of bending something stiff, or make smaller