Presentation on theme: "A Brief Overview of Bridges"— Presentation transcript:
1A Brief Overview of Bridges Preparation for LabGrade 7 ScienceMs. Willis
2Learning Goals /Success Criteria I can describe different bridge types.I can identify geometric shapes used in bridge design.I will understand my expectations for the science lab in building our a model bridge.
3BridgesBridges provide important links between places. They enable us to get to resources, conduct commerce, travel and visit other people. The design of bridges is important to the transportation networks we depend on.
4Types of BridgesThere are many kinds of bridges, but generally they can be classified into 4 main groups:Beam bridge (includes truss bridges)Arch bridgeSuspension bridgeCable-stayed bridge
5Arch BridgesThe Arch bridge is the shape of a curved arch with abutments at each end.Arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side.This type of bridge was often used by the Romans who built structures out of stone.
6Arch BridgesThis is a Roman Aqueduct in France. It was difficult to span wide distances without using several arches with supports. The piers to support these arches can restrict water flow which can be hazardous. These bridges can date as far back as the 1300s!
7Arch Bridges A modern arch bridge..... This bridge is located in Southern California.
8Arch BridgesNote: A voussoir (pronounced /vuˈswɑr/) is a wedge-shaped element, typically a stone, used in building an arch or vault.
9Suspension BridgeA suspension bridge is a type of bridge in which the deck (the load-bearing portion) is hung below suspension cables on vertical suspenders. The first modern examples of this type of bridge were built in the early 19th century.These bridges can support tremendous weight and span a wide distance.
10Suspension Bridges Mackinaw Bridge in Michigan Total Length: 8 038m Length of main span: mHeight: 168mLongest suspension bridge in Western Hemisphere.
12Cable-Stayed BridgesA cable-stayed bridge has one or more towers (or pylons), from which cables support the bridge deck.There are two major classes of cable-stayed bridges: harp and fan.Harp bridge in Dublin, IrelandFan bridge in Washington, USA
13Cable-Stayed BridgesCable-stayed bridges differ from their suspension predecessors in that they don't require anchorages, nor do they need two towers.Instead, the cables run from the roadway up to a single tower that alone bears the weight. The tower of a cable-stayed bridge is responsible for absorbing and dealing with compressional forces.