GROUP NO. 06

2011-Te-44

2011-Te-48

2011-Te-59

AQSA RIAZ

HIBA ARSHAD

ADNAN MAQSOOD

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

Span range Short

Material Timber, iron, steel, reinforced concrete, prestressed concrete

Movable No

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

Culvert Basics

Hydraulically short conduit which conveys stream flow through a roadway embankment or past some other type of flow obstruction

Culvert