types of bridges
DESCRIPTION
Types of BridgesTRANSCRIPT
What is a bridge.? Different types of bridges. Descriptions. History Working. Culverts Type of culverts Depiction References.
Table of contents
Bridge is a structure built to span a valley, road, river, body of water, or any other physical obstacle.
Designs of bridges will vary depending on the function of the bridge and the nature of the area where the bridge is to be constructed.
Bridge
700 A.D. Asia
1,304 years ago
100 B.C. Romans2,104 years ago
Clapper BridgeTree trunk
Stone
Arch design evenly distributesstressesNatural concrete made from mud and straw
Roman Arch Bridge
History of Bridge Development
Great Stone Bridge in ChinaLow bridge
Shallow archAllows boatsand water to passthrough
History of Bridge Development
Truss Bridges
Mechanics of DesignWood
Suspension Bridges
Use of steel in suspending cables
1900
1920
Prestressed ConcreteSteel
2000
Compression
Tension
Basic Concepts
Span - the distance between two bridge supports, whether they are columns, towers or the wall of a canyon.
Compression –
Tension -
Force -
Concrete has good compressive strength, but extremely weak tensile strength. What about steel cables?
Basic Concepts
Beam - a rigid, usually horizontal, structural element
Pier - a vertical supporting structure, such as a pillar
Cantilever - a projecting structure supported only at one end, like a shelf bracket or a diving board
Beam
Pier
Load - weight on a structure
There are six main types of bridges:1. beam bridges2. cantilever bridges 3. arch bridges4. suspension bridges 5. cable-stayed bridges and 6. truss bridges
Types of Bridges
Consists of a horizontal beam supported at each end by piers. The weight of the beam pushes straight down on the piers. The farther apart its piers, the weaker the beam becomes. This is why beam bridges rarely span more than 250 feet.
beam bridges
Forces When something pushes down on the beam, the beam bends. Its top edge is pushed together, and its bottom edge is pulled apart.
Beam bridge
A cantilever bridge is a bridge built using cantilevers: structures that project horizontally into space, supported on only one end.
cantilever bridges
The arch has great natural strength. Thousands of years ago, Romans built arches out of stone. Today, most arch bridges are made of steel or concrete, and they can span up to 800 feet.
arch bridges
Forces
The arch is squeezed together, and this squeezing force is carried outward along the curve to the supports at each end. The supports, called abutments, push back on the arch and prevent the ends of the arch from spreading apart.
Types of Bridges
Arch Bridges
Suspension Bridges
This kind of bridges can span 2,000 to 7,000 feet -- way farther than any other type of bridge! Most suspension bridges have a truss system beneath the roadway to resist bending and twisting.
Types of Bridges
Forces
In all suspension bridges, the roadway hangs from massive steel cables, which are draped over two towers and secured into solid concrete blocks, called anchorages, on both ends of the bridge. The cars push down on the roadway, but because the roadway is suspended, the cables transfer the load into compression in the two towers. The two towers support most of the bridge's weight.
Types of Bridges
Suspension Bridges
cable-stayed bridges
The cable stayed bridge is newer than the other types of bridge. Large upright steel supports are used to transmit the load into the ground.
Truss Bridge
All beams in a truss bridge are straight. Trusses are comprised of many small beams that together can support a large amount of weight and span great distances.
•Pontoon bridges are supported by floating pontoons with sufficient buoyancy to support the bridge and dynamic loads.
•While pontoon bridges are usually temporary structures, some are used for long periods of time.
•Permanent floating bridges are useful for traversing features lacking strong bedrock for traditional piers.
•Such bridges can require a section that is elevated, or can be raised or removed, to allow ships to pass.
Types of Bridges
Floating Bridge