SUSPENSION BRIDGES

Presented by:- Gangaram Sapkota CIB09017

Suspension Bridge

•Deck is hung below suspension cables on vertical

suspenders

•Usually has two towers that hold up the horizontal

cables.

•From these main horizontal cables hang vertical

cables that are attached to the deck of the bridge

•Used for the longest spans.

•Cables- suspend the roadway (tension)

•Towers- stabilize wire cables (compression)

•Anchorages- key to the structure, mass that keeps

cables tight, gives the bridge structure

Suspension Bridge- Parts

With anchorages

Without anchorages

Suspension Bridge

Suspension Bridge- Structural Analysis

 The main forces are tension in the cables and

compression in the pillars.

Since almost all the force on the pillars is vertically

downwards and they are also stabilized by the main

cables, the pillars can be made quite slender.

Suspension Bridge- Structural Analysis

Cables suspended via towers hold up the road

deck. The weight is transferred by the cables to the

towers, which in turn transfers the weight to the

ground. This is a type of bridge that is able to

stretch to extreme lengths and be capable of lasting

a very long time.

It is suspended in the air, is able to withstand

natural disasters such as earthquakes or tornadoes

better than another type of bridge.

Suspension Bridge- History

• Early suspension bridges - simple and crude with a

narrow walkway that was suspended from chains or

rope.

• Used in the 7th century by the Mayans, and later in

China and Tibet.

• However these theories weren’t proved, the first

suspension bridge design was drawn by Faust

Vrancic in his book “Machinae Nove” in 1595.

Suspension Bridge- Types

Simple Suspension Bridge

It is the oldest type of suspension bridge, usually

constructed as a foot bridge. In this type a flexible deck is

provided which is supported by the cables anchored to the

earth.

Golden Gate Bridge, San Francisco

Suspension Bridge - Types

Kingston Rhinecliff Bridge, New York

Under spanned suspension bridge

the main cables hang entirely below the bridge deck, but are still anchored into the ground in a similar way to the conventional type

Suspension Bridge

Stressed Ribbon Bridges

A modern descendant of the simple suspension bridge. The deck lies on the main cables, but is stiff, not flexible.

Maldonado Bridge, Uruguay

 

-They can span longer distances than any other type

of bridge. 

- They require less material to build, resulting in

reduced construction cost. 

- Don’t have to shut down a waterway in order to

build the bridge. 

-They can withstand earthquakes better than stiff

conventional bridges. 

 

 

Suspension Bridges - Advantages

-Road deck can vibrate and even twist is high

winds. 

-The road deck lacks the stiffness required to carry

heavy railroad traffic. 

- Some areas of the bridge are difficult to install

and maintain. 

Suspension Bridges - Disadvantages

The Akashi-Kaikyo bridge in Japan

The longest bridge in the world - 6529 feet long.

Suspension Bridges

The Great Belt Bridge, Denmark

Suspension Bridges

Humber Bridge, United Kingdom

Mackinac Bridge, USA

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