In the past, the arch bridge design was very popular because of its excellent support ability. Today, you can still find such bridges over 2,000 years old, built during the ancient Roman Empire.
Many multi-storey structures, including aqueduct systems, also use arch bridge design as a solution to transport people, materials, or supplies to nearby communities.
There is historical evidence that the ancient Egyptians discovered the advantages of arch design more than 5,000 years ago. Its versatility has long been part of human culture. It is reasonable to apply the arch design to the construction of bridges and roads because the two stone pillars at the two ends of the bridge will act as the basic bearing points for the bridge span. Thanks to them, the bridge will have better resistance, and more flexibility to adapt than other designs.
As the forces acting on the arch are transmitted to the ground, it is released to the outside at the base of the arch. This pressure increases as the height of the arch decreases. That is why this design is such an effective way to create structures with support functions.
There are three common types of arches that you often see in bridges today: fixed arches, double-articulated arches, and three-joint arches. Fixed arch is most commonly used when building reinforced concrete bridges, but it is also useful if tunnel construction is required. The efficiency of this type of arch will be highest when the span is short.
Dual-joint arches are useful for bridges with longer spans, with pivot joints at the base allowing rotation. This design creates space for components to move during thermal contraction or expansion.
Finally, the three-joint arch has an additional pivot joint in the mid span, allowing components to move in opposing directions to better cope with temperature changes.
When the span of the bridge is too large, engineers often use the arch design because of its advantages of support and flexibility. The length between two support points on an arch bridge can be much longer than a straight bridge because of the way it transmits force downwards. Not only does that allow you to create a longer deck, but it also means the bridge will have greater horizontal support to handle heavier loads.
Rossgraben Bridge (Switzerland)
The Rossgraben Bridge, located near Bern, Switzerland, is a prime example of this advantage. Even when a three-joint design is used, it is still possible to create a bridge span of medium length without the need for many supporting posts.
The curvature of the arch bridge design gives the deck plank and the overall structure more support than other solutions. If something heavy passes over the bridge, its mass will create a downward force, causing the bridge to sag. Because the two supporting columns allow this mass to be transmitted along the entire structure in a consistent manner, there is less stress on the structure during movement. That means fewer quality problems for the bridge, as the force is evenly distributed helping to ensure that the bridge can effectively adapt to changes in heat and pedestrians.
When considering arch bridges built today, most are made from concrete, steel, aluminum, or a combination of those materials. If you look at ancient monuments with arch designs left over from Roman times, you’ll find that even though they’re made of stone, they can last a long time as long as they’re built properly. We still use some of these ancient structures today, such as the Pula Arena in Croatia.
Pula Arena (Croatia)
This arena was built in the 1st century, and is one of the largest surviving arched structures in the world. It has two floors of stone arches, and is still the venue for concerts, film festivals, and even two professional hockey tournaments.
The Romans started building the arch after they perfected the design, because they realized that the arch structure could stand up to the natural environment better than traditional column or pillar designs, which were also used during that period. That is an advantage of arch bridges that still exist today. Even if you look back at the advantages of the semicircular arch design, you’ll see this as well – though the arch design is much more efficient.
This strength means that bridges can better withstand natural disasters, such as earthquakes or floods. Besides, this design can still give you the advantage of the distance of the spans. That is why there are more than 1,000 ancient structures in more than 25 countries still standing today even though they are over 2,000 years old.
The arch bridge design is inherently solid, which is why it is a popular choice for bridges with long and high spans. As this structure goes through a long time, the bridge design will start to become more solid. That’s because the compression on each of its sides will begin to flatten the arch, creating a U-shape with less curvature. This process helps to better distribute the weight of the decking board towards the piers, while also making the entire surface more stable.
Modern bridges do not have this advantage, because they are made from lower quality materials. Concrete does not last over the years, so maintenance is required to ensure the structural integrity is not compromised.
One of the problems faced by other bridge designs is the deformation of the piers over time due to the load the bridge is subjected to across the deck. When the downward force compresses an arch, the transfer effect reduces the load on the bridge. This advantage can help reduce maintenance costs for arch bridge designs.
Because arches are so effective in carrying loads and increasing span spans, there are many shapes that can be applied during bridge construction. This means engineers have more options when it comes to calculating the overall shape of the structure. You can opt for a thinner, lighter design with a braced arch if you prefer. The Romans often used brick arches because they could be stacked to increase height and solve difficult-to-build bridges.
Bridge designers can also use balance points, horseshoes, trefoils, parabolas, triangles, ellipses, and Tudor designs to create a bridge that is both beautiful and functional.
Juscelino Kubitschek Bridge (Brazil)
The Juscelino Kubitschek Bridge over the Paranoa River in Brazil is a prime example of this advantage. It has a 3-arch design with supporting cables to help drivers cross the river safely. Each arch is joined together to increase stability, while also allowing the construction of a stronger deck that can handle significantly higher volumes of traffic. As long as you have a clear span, the right deflection, and use the right arch stone to match the other curvilinear segments of the bridge structure, you’ll have an extremely solid bridge design. can withstand almost any kind of environmental conditions.
You can build an infinite number of spans on an arch bridge if you want, but there’s a problem here. You will need to use multiple arches in a bridge to do that. That’s why you often see ancient Roman structures that still exist today using a superimposed design – usually 2-3 tiers of arches. If you increase the bridge length, you have to add more arches.
If the end point of one arch is too far from the end point of another arch, the transfer effect will disappear. Every time there is pressure on an arch, or the radius of the arch is increased, the bridge structure weakens.
Given enough time and resources, anyone can build a bridge as long as they want. It could be a bridge made of a tree over a creek, or it could be the longest bridge in the world. But if you want to use arch bridge design, you have to understand the pressure that the piers have to support both inside and outside. You also have to calculate that the material and support system have enough strength to create the transfer effect.
Builders and designers must have good skills in reading drawings, understand the geological features of the area, and have the mathematical and architectural knowledge to build a successful bridge. If any critical component is missing, the whole structure will sooner or later fail – a defect that can lead to life-threatening consequences.
If the bridge’s supporting structures do not perfectly match the arch design, it is impossible to place the keystone correctly. When this problem occurs, the distribution of mass down the piers is no longer balanced. Even when modern building materials are highly durable, even a fraction of a centimeter deviation can increase the risk of damage to the entire bridge. The errors are simply too difficult to fix even a small error in the construction process.
The displacement advantage of a two- or three-joint arch bridge is great in areas where the temperature changes frequently and there are significant temperature differences between certain time periods. However, sometimes the displacement, or flexibility, of the arch can exceed what the deck can handle. When too much displacement occurs, especially simultaneously from many different directions, it can lead to complete failure of the bridge.
An ordinary arch bridge requires more supporting pillars on both sides than other bridge designs because of the stability and mobility of the bridge structure. It is not unusual for humans to calculate additional support systems when the pillars at either end are not strong enough. This disadvantage is why some sites use columns or some other form of support for their arch bridges. The artificial support system can only increase the strength of the bridge by a certain amount, which may not be enough to reach the load threshold of the bridge design.
There must be a stable and solid support system on both sides of an arch bridge so that it can support any type of deck. If in some locations this support system cannot be guaranteed, there is no way to replace it. You must have two strong points to support the bridge, even if the span is small, for the arch bridge design to be stable. Modern materials such as steel can withstand greater stresses and strains, so you have more options when it comes to the placement of your support posts – but one thing is for sure, you can’t just resist help one side!
Chaotianmen Bridge (China).
If you need longer spans, then you must have more force distribution points. That’s why the world’s longest arch bridge today – the Chaotianmen Bridge on the Yangtze River – is only about 0.55km long. Modern bridge designs can extend to more than 48km across the river.
A typical arch bridge requires regular maintenance to ensure that the supporting pier system always distributes weight to the arches as designed. That means engineers have to regularly survey the bridge to make sure it doesn’t weaken over time. Wear and tear is inevitable, even with durable materials like steel, so it’s important to intervene early to repair when damage is detected.
Honeymoon Bridge over Niagara Falls.
If a bridge is not regularly maintained, disaster can occur. One of the best examples is the Honeymoon Bridge over Niagara Falls, connecting the US and Canada. The bridge collapsed in 1938 when a sudden hurricane caused a 30-meter-long glacier to smash into the foot of the bridge, displacing the bridge’s mass.
Because of its complexity, it takes more time to build an arch bridge than other designs. Sometimes this time is three times the usual, making it unsuitable for places where an early bridge is needed. This disadvantage is also the reason for the higher construction cost of the arch bridge, because the labor required for the project will be more.
Even if the government partially financed the cost, the risk of additional time and cost is still too great when choosing an arch bridge design.
The arch bridge is one of the most efficient designs ever invented by man in history. We continue to use it to this day, with modern materials such as steel and concrete, because of its incredible durability and flexibility, as well as a lower risk of damage than conventional devices. other design.
Each arch has a certain maximum length. Engineers must carefully calculate in the design stage to ensure this structure can achieve inherent durability. Then the contractors undertaking the project must adhere to every detail of the drawing to ensure the best results.
The pros and cons of arch bridges are the basic thing to consider when building a bridge. You can also apply it to other areas of your life, like building a roof or installing windows, because the downward force is essentially the same in every situation.