A suspension bridge is a type of bridge where the deck (the load-bearing portion or essentially, the road) hangs below suspension cables on vertical suspenders. One of the most famous examples of this kind of bridge is the Golden Gate Bridge in San Francisco. While modern examples have been built since the early 19th century, simple suspension bridges (ones that lack vertical suspenders) are used in several mountainous regions of the world. But what is the reason for choosing suspension bridges over other kinds of bridges?
List of Pros of Suspension Bridges
1. It can extend long distances.
A suspension bridge can span between 2,000 to 13,000 feet (the farthest any kind of bridge can accommodate). As such, this is the bridge type preferred when considering the coverage of very long distances. Three suspension bridges with the longest spans are the Akashi Kaikyō Bridge in Japan (more than 1,991 meters), the Xihouen Bridge in China (1,650 meters) and the Great Belt Bridge in Denmark (1,624 meters).
2. It is not expensive to build.
While it does cost a lot of money to make, building a suspension bridge only requires a minimal amount of materials. To build one, anchorages, cables and roadways are the minimum requirements. Because of this, communities without much funds that want to build a functional bridge can look at this option. Despite not costing much, suspension bridges can still look visually appealing as well.
3. It is not high maintenance.
Not much is needed to ensure the longevity and integrity of suspension bridges. However, proper maintenance is required for it to last long. The main point here is that communities don’t need large expenses to maintain this kind of bridge.
List of Cons of Suspension Bridges
1. Wind makes it vulnerable.
A suspension bridge is fitted with a truss system beneath the roadway so it doesn’t bend and twist. However, the concept of a suspension bridge is to make it flexible enough to move with the wind but not break up. This simply means that a bridge can be susceptible to damage when the wind is too strong or high. In addition, putting too much weight on this kind of bridge can trouble its cables and as such, they can break (especially when there are strong winds).
2. Limitations are put on suspension bridges.
Suspension bridges are held by cables and they can only hold up as much. This is one of the reasons why roads on these kinds of bridges are light. Because of this, suspension bridges can’t accommodate heavy loads and have weight restrictions. This is why only certain types of traffic can pass through a suspension bridge. In fact, some communities have put restrictions on what can pass through the bridge at a given time.
3. Application is limited.
Suspension bridges are susceptible to strong winds. This is why they can’t be built strong and stiff and because of that, they can only support general traffic. In short, they can’t support heavy freight that is possible with rails.
Suspension bridges also require anchorages which need a huge land area. Without this, this kind of bridge cannot be constructed.