Brian Brenner Aaron Levine Cindy Tran Bridges Brian Brenner Aaron Levine Cindy Tran

Some Uses of Bridges Walkways Highways/Roads Railways Pipelines Connecting lands Crossing rivers and canyons

What makes a bridge stay up? Forces Compression – a pushing or squeezing force Tension – a pulling or stretching force Let’s Try It! With your neighbor… View the types of forces involved in buildings http://www.pbs.org/wgbh/buildingbig/lab/forces.html

What kind of forces do bridges have to be prepared for? Load – forces that act on structures Structures must withstand loads or they’ll fall apart! In order to build a structure, you need to know what kind of external forces will affect it. View the types of loads that affect big structures http://www.pbs.org/wgbh/buildingbig/lab/loads.html

Types of Bridges Arch Truss Cantilever Cable-Stayed Suspension Beam

Arch Bridges Keystone – the wedge-shaped stone of an arch that locks its parts together Keeps the bridge from collapsing inward Abutments – the structures that support the ends of the bridge Keeps the bridge from collapsing outward

Arch Bridges LIVE LOAD Works by Compression

Arch Bridges Where have you seen these bridges?

Cold Spring Arch Bridge, Santa Barbara, CA

Marsh Rainbow Arch, Riverton, KS

Pont du Gard, Nimes, France

Beam Bridges Oldest known bridge and simplest to design and build A horizontal beam is supported by vertical piers

Beam Bridges Works by Tension and Compression LIVE LOAD

Beam Bridges Where have you seen these bridges?

Simple beam bridge Eagle County, Colorado

Continuous span beam bridge Chesapeake Bay Bridge-Tunnel Cape Charles and Virginia Beach, Virginia

Cable-Stayed Bridges Piers – the vertical supporting structures Also known as columns Cables – thick steel ropes from which the deck is suspended Deck – the supported roadway on a bridge

Cable-Stayed Bridges Works by Tension AND Compression LIVE LOAD

Cable-Stayed Bridges Where have you seen these bridges?

Zakim Bridge, Boston, MA

Sunshine Skyway Bridge, Tampa, FL

Sundial Bridge, Redding, CA

Suspension Bridges Similar to Cable-Stayed Different construction method Tower – holds up the cables Anchorage - the ends of the cables are attached to these

Suspension Bridges Works by Tension and Compression LIVE LOAD

Suspension Bridges Where have you seen these bridges?

Golden Gate Bridge, San Francisco, CA

Brooklyn Bridge, Brooklyn, NY

Verrazano-Narrows Bridge, New York, NY

Truss/Cantilever Bridges Support comes from interlocking triangles Cantilever bridges are a complex version of truss bridges (supported by balancing)

Truss/Cantilever Bridges Works by Tension and Compression LIVE LOAD

Truss/Cantilever Bridges Where have you seen these bridges?

Truss Southern Pacific Railroad Bridge, Tempe, AZ

Cantilever Firth of Forth-Forth Rail Bridge, Edinburgh, Scotland

How long can a bridge be? Span – length of a bridge Beam Bridges Rarely span more than 200 feet Why? The farther apart its piers, the weaker the beam becomes. Suspension Bridges Can span 2,000 to 7,000 feet Way farther than any other type of bridge!

Engineering Engineering – the use of math and science to solve real world problems (like crossing a river) Civil engineering – designing and building bridges, roadways, tunnels, buildings, dams, etc. Architect – works with engineers to design bridges Civil Engineer

Branches of Civil Engineering Structural – bridges, roads, buildings Geotechnical – foundations, excavations, and tunnels Transportation – roads, traffic control, airports Environmental – human impact on the environment

Other Types of Engineering Mechanical – design machines and moving parts Electrical – design electrical equipment Chemical – design processes for mixing chemicals Computer – design computer hardware and software

Questions?