Suspension Bridges Advantages and Disadvantages

There are many types of bridges that have been built around the world and suspension bridges remain to be regarded highly when it comes to aesthetic appeal. Having existed for a more than a hundred years, these bridges are knonwn for functionality as well. In the United States, Brooklyn Bridge, the George Washington Bridge and the Golden Gate Bridges are three examples. Conversely, the longest suspension bridge in the world is found in Japan, the Akashi Kaikyo Bridge standing proudly at a length of 6,432 feet.

There are simple and modern suspension bridges that can be found in different parts of the world. The former is a type of bridge considered to be the longest-running type. In Peru, the Incas have been known to use this type of suspension bridge to transport livestock and help them with agriculture. This type of bridge is usually built between two high locations and attached by ropes and cables. Its main feature is a downward arc that should be in the surface to support the weight of the people and whatever is passing through it.

Meanwhile, a modern bridge has vertical supports that significantly add to its attractiveness. Having been in existence since the 19th century, this type of suspension bridge is capable to withstand the weight of trains and vehicles. Its deck hangs below suspension cables that are held by vertical supports. Usually, towers are built to suspend the cables with the large horizontal cables being firmly supported by smaller cables that are as long as the length of the bridge.

Just like other types of bridges built over the years, suspension bridges have benefits and setbacks. Here are some of the advantages and disadvantages of suspension bridges.

List of Pros of Suspension Bridges

1. Low Construction Costs
What makes suspension bridges practical is the inexpensiveness of these bridges due to required materials needed for construction. With three basic necessities such as cables, anchorages and roadways, suspension bridges are possible to construct. Having said, this, suspension bridges are great solutions to provide communities with functioning and useful bridges without much need for funding. These are beneficial in areas that lack infrastructure funds. And in the case of allotting budget for projects, the inexpensive costs in building these types of bridges can allow for other projects to be financed.

2. Long Span
Another advantage of suspension bridges is the possibility to construct them at different lengths, from 2,000 to 13,000 feet and is lengthier than other types of bridges. This makes it possible to build suspension bridges to connect very long distance locations. Depending on the demand and possibility given, these bridges can be underspanned like the Pont des Bergues and the Micklewood Bridge. On the other hand, three long suspension bridges are in Denmark, Japan and China.

3. Ease of Maintenance
Apart from inexpensive construction costs, suspension bridges are known for their minimal maintenance requirements. Once construction is completed, there are no immediate needs for additional materials like cables. What is called for is simply regular maintenance. Moreover, it is known for durability and longevity, making major repairs not needed as often. Consequently, maintenance costs are also not that high.

4. Versatility
Suspension bridges do not only cost less to build, they can also be built practically anywhere so long as there are places for building support towers and anchorages. This is also because of the design which is suspended in the air, no inflow restrictors are needed to be placed underneath. They can also bear the beatings of earthquakes.

5. Attractive
Tourists, local and foreign in America love to cross the Brooklyn Bridge and visit the Golden Gate Bridge in San Francisco. Compared to truss and beam bridges, suspension bridges are more aesthetically pleasing because of the different shapes of these bridges. The curved and linear features of these bridges make them structurally beautiful. This is on top of the cables giving support to these bridges, making them versatile bridges.

List of Cons of Suspension Bridges

1. Loss of Income
Despite the low costs of constructing suspension bridges and the job opportunities they offer, the length of time needed to finish building these bridges are long. What happens is that the businesses that are within the vicinity will be affected since business operations will be hampered. Consequently, there will be loss of sales and profit. This can have a negative impact on the economy of the city or town. Also, bridges built to connect locations between bodies of water can affect the course of ships carrying supplies since they need to divert their routes. This can also result to loss of money since deliveries of goods can take longer.

2. Weak in Winds
Despite flexibility and strength to withstand earthquakes, these bridges are not too strong when it comes to powerful winds caused by hurricanes. Too much strong winds can result to damages to suspension bridges. A classic example is the Tacoma Narrows Bridge which collapsed on November 7, 1940 in winds of at only 40 miles per hour. Although the disaster was blamed on design and construction, what happened that time presented risks associated with suspension bridges.

3. Load Limitations
Another disadvantage of suspension bridges is the material used which are the cables. These cables have limitations when it comes to bearing the weight of loads. Although it can allow a minimal weight with regard to vehicles passing through, too much weight can lead to the breaking of cables.

4. Limited Applications
Suspension bridges, despite their cost-effectiveness in construction and flexibility when it comes to site location, have limitations when it comes to its use. This is because they can be destroyed by strong winds and not durable enough to hold limitless weight, careful consideration should be taken before construction. That said, they can only be used by general traffic.

Suspension bridges have retained popularity around the world and this is evident with the number of these bridges in the United States. However, along with pros also come the cons. This is why engineers building these bridges should study the design and ensure requirements in building these bridges are met with accuracy and compliance.

Author Bio
Natalie Regoli is a child of God, devoted wife, and mother of two boys. She has a Master's Degree in Law from The University of Texas. Natalie has been published in several national journals and has been practicing law for 18 years.