Arch bridges are among the many classic architectural works that you can see throughout history, which many of them were inspired by Roman Empire architecture. Their versatility of uses and their unique design have made them a staple in bridge construction for as long as we might see. Set up with two abutments that serve as base points for all the pressure put on them, they are a very flexible and strong type of a bridge. By incorporating arches into their design, they have gained some definite advantages. However, no matter how fantastic their design is, there are still some drawbacks that cannot be avoided and must be taken into consideration during the construction process. Let us take a closer look at the pros and cons of arch bridges.
List of Pros of Arch Bridges
1. They can provide higher levels of resistance.
The bridge’s curved design of its arch gives it an extraordinary point of strength. It allows itself to have a higher level of resistance to the bending forces that may try to modify it. Because both of the arch’s ends are fixed, the horizontal forces that are placed on it, like that from driving, are displaced equally.
2. Their design is good when it comes to pressure.
By using arches when designing these bridges, the weight and pressure of anything that cross them will be able to go straight down, instead of dispersing across their entirety. This is done to make sure no single part of the bridges takes on too much pressure.
3. They can be made from virtually anything.
An arch bridge can be made from bricks, stone or virtually any natural material that can withstand forces brought about by compression. This would allow local communities to build an arch bridge by using their own materials without using iron for steelwork that might not be available to them.
4. They come with no distortion.
An arch bridge’s half circle shape is purposely designed to ensure that no damage or distortion would occur to the bridge because of excessive amount of pressure or weight. This quality is a very beneficial in a way that it cuts down the cost that would be needed for maintenance.
5. They become stronger through time.
An arch bridge is built to compress, and when such compression occurs, the bridge would actually become stronger than when it was initially built. It is due to this fact that many arch bridges also have a huge amount of dead weight placed above each of their arches that are incorporated into their architectural design. The main reason for this is to support loads through the natural strength-gaining process.
6. They are structurally sound.
The modern version of the arch bridge, which is known as the long-span through arch bridge, is not as aesthetically pleasing as other designs, but it is structurally sound due to its composition of lighter materials. In fact, it can now be constructed of steel and will cover a longer span.
7. They are economically advantageous in some way.
Arch bridges are considered as an economical way to traverse small distances. They are also able to cope up with bending forces.
List of Cons of Arch Bridges
1. Their construction is a tough job.
When it comes to arch bridges, time will be the biggest problem. Their structure has to be designed meticulously. Moreover, constructing them will be very intensive with regards to time and labor.
2. Their spans are limited.
An arch has natural starting and ending points. With these points, you can calculate how much weight an arch can stand based upon its size and the scope of the materials being used. For arch bridges, they can only be constructed at a certain size, so either multiple arches have to be built into their foundation, or other reinforcement materials should be included to support the needed loads the bridges will face.
3. There can be constraints on their locations.
Take note that these bridges can be constructed only in particular locations, where the foundation on both sides is stable and solid, as these structures need more support from their sides. However, some modern designs of arch bridges, which are made of reinforced concrete or steel, can tolerate the load by tension within their structure. This is the reason why the transfer of horizontal loads forces the reduction and cancellation of abutments, thereby consequently allowing their construction on a weaker ground as well.
4. More supports are usually required.
One big disadvantage of arch bridges is that they require more support from their sides than a normal bridge would. They must be situated where there is a structurally sound bank or an abutment in order to help support them.
5. They require extra maintenance.
Due to the fact that natural materials are generally used in building these bridges, the flexibility past also has a disadvantage. Arch bridges will flex and move under wind loads, which cause the mortar that combines the natural materials together to disintegrate and crack over time. Because of this, ongoing maintenance must be done more often, which adds extra costs to prolong these bridges’ life.
6. It can take a long time to build one.
Arch bridges have to be constructed in a certain way in order for them to work at their best, which means it would take a long time to complete them. This is especially true considering that natural materials are being used for their construction. Though they would last longer compared to other types of bridge, the lengthy time for construction can sometimes be detrimental.
7. Their construction requires high costs.
The sheer amount of construction materials can really add up to the high cost of building these bridges. Aside from the materials, an incredible amount of labor, including that from architects and engineers, and time is also required for their completion.
Arch bridges certainly look beautiful and definitely serve a specific function. Being strong and flexible, they are reliable in helping people get to where they need to go. By weighing the pros and cons listed above, you can then get a good idea whether these architectural structures are perfect for your own community.
Natalie Regoli, Esq. is the author of this post and the editor-in-chief of our blog. She received her B.A. in Economics from the University of Washington and her Masters in Law from The University of Texas School of Law. In addition to being a seasoned writer, Natalie has almost two decades of experience as a lawyer and banker. If you would like to reach out to contact Natalie, then go here to send her a message.