How Cable stayed bridge is different from Suspension bridge?

How Cable-stayed bridge is different from Suspension bridge?

There is a fine line between Cable-stayed bridge and suspension bridge? Here I shared some important design concept, types, and advantages of the cable-stayed bridge?


Cable stayed bridge


Cable-stayed bridge



In the cable-stayed bridge, the deck of the bridge is directly supported and connected to the tower via cables (Instead via suspended cables).

Or,

The definition of the cable-stayed bridge can be defined as, the bridge in which the cables hold the deck by directly connecting it to the towers.

There are many variations in designing this bridge like Mono, Harp, Fan, Star etc.

The cable-stayed bridge may look similar to the suspension bridge, but both are different in terms of structural design, appearances, load distribution etc.

In the case of suspension bridge cables are connected to the towers via suspended cables.

And for the cable-stayed bridge, cables are directly connected to the towers.

It's necessary that you have a basic structural knowledge about the suspension bridge so that you can differentiate it from the cable-stayed bridge.

Please go through my previous article about the Suspension bridge.

Venetian inventor Fausto Veranzio was the man behind the concept of the cable-stayed bridge.
cable stayed bridge advantages




Cable-stayed bridge vs Suspension bridge


One of the major difference is that the cable-stayed bridge doesn't require any anchorage or any suspended cables.

Other major difference is that between two bridge lies in how the cables are connected to the towers.

A suspension bridge is most suitable where the required length of the span is great.

And Cable-stayed bridge is built when a medium length of the span is required (where the suspension bridge is not an economical option).

In terms of load distribution, the Total load of the Cable-stayed bridge is transferred to the towers by the cables.

Where, in case of a suspension bridge, some portion of the load is carried by the suspended towers and a huge amount of load is taken care by the anchorages connected at both end of the bridge.


Now, I hope you might get to know the difference between the cable-stayed bridge and the suspension bridge.



Types of Cable-stayed bridge


Depending on the structural design, we can divide this classification into five way-


1.  Side-spar cable-stayed bridge


It consists of only one tower which is supported only on one side. This principle can be used to build a curved bridge.


3. Multiple-span cable-stayed bridge


This type of bridge consists of more than three spans. 

This type of bridge design is considered as a complex design as the load coming from the main span are not anchored back near the end junction.

This causes the structure less stiff than other types of cable-stayed bridges.

To overcome this problem, additional support is required to make the structure stiff.

Additional support means cross bracing, twin-legged towers, anchorage piers have to be applied to stabilize the bridge.


4. Extradosed bridge

An extradosed bridge is usually suitable for medium to long span (100-250 meters).

Some Main feature of this bridge is:

  • Deck of the bridge is stronger, stiffer and thicker than the normal deck of a cable-stayed bridge.
  • The height of the bridge tower is comparatively very less.
  • Towers are frequently placed to support the deck.

Load distribution of this type of bridge is slightly different. 

In the case of a cable-stayed bridge, 80% of total load which coming to the deck are supported by the cables and remaining supported by longitudinal girder.

But for extradosed, only 20-60% of the load is supported by the cables.


5. Cable-stayed cradle-system bridge


Here is the latest one from the series. The first bridge used by this system was constructed in 2006.

This cradle-system carries strands/cables within the stays as a result strands act as an individual and allowing for replacement of individual strand.



Advantages of Cable-stayed bridge


Some of the most important advantages of Cable-stayed bridge are given below:

1. Strong and economical at the same time


Strong design is one of the key ability of this structure. This type of bridge is stronger than the traditional suspension bridge as the cables in this bridge is able to take more pressure.

Deck of this bridge is also thick, stiff and strong.

Due to the high rigidity of the structure, it shows less deformation under high live loads.

This has a normal tendency to resist environment changes.

The cable-stayed bridge is a type of bridge which requires less material means less time is required with the help of less number of labor.

This can save your budget as well as time.


2. Less time consuming

As this requires less material, it's construction process is pretty simple. 
The cable-stayed bridge doesn't require any anchorage, therefore, it consumes less time to complete the construction.



3. Longer span can be achieved


This design allows us to expand the span by connecting the deck section one to another.
By this process, we can extend the length of bridges of almost indefinite length.

 The Jiaxing-Shaoxing Sea Bridge in China is an example of this method which is the longest cable-stayed bridge in the world.

Its length is almost 10,000 meters and is able to carry heavy traffic.

Disadvantages of Cable-stayed bridge


1. Not ideal for longer span:


Cable-stayed bridge has limitation over the length of the span. It is most suitable when the required span length is medium to long.

That's where suspension bridge takes the attention.


2. Maintenance difficulties


maintenance and inspection can be difficult in this case. cables are more prone to corrosion, which needs more regular maintenance. 


Pros and cons are there in the cable-stayed bridge. Though it does have few limitations, it is still economical and efficient.


cable stayed bridge vs suspension bridge

Conclusion


Now you may have an idea about the importance of cable-stayed bridge in civil engineering.
Though cable-stayed bridge has some limitation in design, it is advantageous for many purposes.
How Cable stayed bridge is different from Suspension bridge? How Cable stayed bridge is different from Suspension bridge? Reviewed by Sk rafiqul islam on October 29, 2018 Rating: 5

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