Arch bridge designs were first used by ancient civilizations, such as the Romans, where they do not only use such a structure for its obvious reason, but also in aqueducts. Commonly found in steep gorges and valleys, an arch bridge comes in many different variations, including the through, deck and tied. The longest of this type of bridge in the world is the one found in China, specifically over the Yangtze River spanning over 1,800 feet. However, this title would be taken from it, when the record-shattering 3,000-foot arch bridge that is planned to be built in Dubai will be realized.
The arch bridge is definitely one of the classic architectural components that we have seen throughout history, with many of such a structure, which originated in the Roman Empire, inspiring modern architecture. You see, arches are being incorporated into some of today’s bridge designs, as they are believed to improve the overall structure. However, there are also some disadvantages to it, just like almost all things. Let us take a look at the strengths and weaknesses of an arch bridge.
List of Strengths of an Arch Bridge
1. It provides a higher level of resistance.
An arch bridge’s curved design gives it an unnatural strength point that allows the structure to have higher levels of resistance to the bending forces that may have the ability to change its form. Because it has two ends that are fixed, any horizontal force that is placed on it, such as those coming from vehicles, is displaced equally.
2. It design is good in terms of pressure.
By using an arch design when creating a bridge, the weight of anything that crosses it will go straight down, rather than being dispersed across the entirety of the structure. This is designed so as to make sure that no single part of the bridge would take on too much pressure.
3. It can be built from virtually anything.
An arch bridge can be constructed from stone, bricks or virtually any other natural material that has the quality of withstanding forces of compression. With that said, local communities can build arch bridges with the use of their own materials without the need of steelwork that they may not have access to.
4. It is structurally sound.
Though the modern version of this type of structure, which is known as the long-span through arch bridge, is not as pleasing in terms of aesthetics compared with other bridge designs, it is structurally sound thanks to the composition of lighter materials. And today, it can even be made of steel and can cover longer spans.
5. It comes with no distortion.
The half circle shape of an arch bridge is purposely designed to make sure that no distortion or damage would occur to the structure due to extreme pressure or weight. Because of this quality, it can reduce the cost that otherwise would be needed for its maintenance.
6. It becomes stronger as it works.
As you can see, an arch bridge is built to compress, so when compression occurs, it actually becomes stronger than when it was initially built. For this reason, many arch bridges are given a lot of dead weight above each of the arches into their architectural design, so they will be able to support loads via the natural process where it gains strength.
7. It offers economic advantages.
Most of time, an arch bridge is regarded as an economical way for people to traverse small distances, thus helping with the economic progress of a certain region.
List of Weaknesses of an Arch Bridge
1. It has a limited span.
Basically, arches have a natural starting and ending point, and the amount of weight they can withstand is calculated based upon their sizes and the scope of the materials being used. An arch bridge can only be of a certain size, so it is either multiple arches are needed for the foundation of the structure or other reinforcement materials should be included to support the loads it will face.
2. It has constraints on location.
To be able to build this type of bridge, a particular suitable location must be chosen, where the foundation on both its sides will be solid and stable, as it would need more support from its sides. However, some modern arch bridge designs, which use reinforced steel or concrete, are now able to tolerate the load by tension within the structure by transferring horizontal loads that forces the cancellation or reduction of abutments, thus allowing this type of bridge to be constructed on a weaker ground as well.
3. It requires extra maintenance.
As natural materials are generally used to build an arch bridge, there is a limit to the flexibility of its design, where it is known that it would move and flex under wind loads, causing the mortar that combines the materials together to disintegrate and crack over time. All these things mean that this bridge requires ongoing maintenance, which can add to the costs of keeping it in good condition.
4. It requires more support.
This type of bridge typically requires more support from its sides than a normal bridge would. As previously implied, it must be built where there is a structurally sound abutment or bank in order to have proper support.
5. It can take long to build.
As an arch bridge has to be constructed in a particular way in order for it to work, it could take long for it to be completed, which is especially true considering that natural materials are being used to build it. Though its life span can be much longer compared with other bridges, its lengthy construction time can be a drawback.
6. It is costly to build.
The sheer amount of materials needed to construct an arch bridge can really add up to its cost. Aside from this, there is an incredible amount of labor and time needed for its completion.
An arch bridge serves a great function and looks beautiful, but it also comes with a set of drawbacks. By weighing its strength and weaknesses, you will be able to decide on whether it is the right type of bridge to use for your community.