Types of Structures

Residential - Structures in which people live.Ex. Single family houses, condominiums,

and apartment complexes.Industrial - Structures used for

manufacturing.Ex. Automobile plants, computer chip

manufacturers and power plants.

Types of Structures

Commercial - Structures built for business.Ex. Supermarkets, shopping malls,

restaurants, and office buildings.Public Works - Structures intended

for public use or benefit.Ex. - Highways, bridges, tunnels,

airports, hospitals, schools and parks.

Terminology

Beam – A horizontal structural member that is supported at two or more points.

Column, post or pier– a vertical structural member that supports a beam or other structure.

Cantilever – the part of a beam that extends beyond a column.

Foundation/Footing- distributes the weight of the structure on the ground.

Forces Acting Upon A Structure

Compression - A force that attempts to shorten or crush an object or material. Occurs along the top edge of a beam.

Forces Acting Upon A Structure

Tension - A force that pulls on an object or material, thereby stretching or elongating it. Tension occurs along the bottom of a beam.

Forces Acting Upon A Structure

Torsion- A twisting force.

Structural Loads

Dead Load – The weight of the structural elements of the structure

Live Load – The weight of objects placed onto the structureStatic - Stationary Load

Dynamic – A load in motion

Types of Bridges

Beam - the earliest and most common bridge form.

Supported at both ends by a pier or foundation. Strength is accomplished by size and type of

material. Beam bridges rarely span more than 250 feet.

SPAN

Types of Bridges

Truss - a structural framework consisting of two or more triangles.

SPAN

Types of Bridges

Components:Top Chord - CompressionBottom Chord - TensionWebbing - Compression and

Tension

Types of Bridges

Arch - carries loads primarily by compression.

Today, most arch bridges are made of steel or

concrete, and they can span up to 800 feet.

Roman Bridge Building

Roman bridges are famous for using the circular arch form, which allowed for spans much longer than stone beams and for bridges of more permanence than wood.

Types of Bridges

Cable Stay - this design carries the vertical main-span loads by diagonal cables in tension.

Cables are attached from the road bed to the tower.

Types of Bridges

Suspension Bridge - carries vertical loads through curved cables in tension. These loads are transferred both to the towers, which carry them by vertical compression to the ground, and to the footings which spread the weight over a large area of the ground.

Types of BridgesCantilever Bridge - generally made with three

spans, of which the outer spans are both anchored down at the shore and cantilever(project) beyond a tower.

A beam is said to be cantilevered when it projects outward, supported only at one end.

The Millau ViaductParis - Barcelona

Related Websites

http://www.pbs.org/wgbh/buildingbig/bridge/index.html

http://www.technologystudent.com/forcmom/force1.htm

What Type of Force is being exerted in each example?