Concrete and steel bridges: composed of concrete and steel, they are the most frequent materials used in bridge building. Concrete and steel are chosen based on the building site's daily traffic and strata. At locations where earthquakes are common, structures made with concrete or steel will tend to be built using stronger materials. Bridges are usually designed with sufficient strength to carry the expected load over their life cycles. However, during an earthquake, these structures can become damaged due to movement under stress of some key components, such as beams or girders.
Wooden bridges: composed of wood, they are generally shorter than other types of bridges (usually because there's no need for them to withstand heavy loads) and often have a single central pier supporting the remaining structure. They are widely used in rural areas when terrain allows for their construction. Wooden bridges are commonly formed from timber that has been harvested from within the local area, although some modern bridges have been constructed from manufactured products. The design and maintenance of wooden bridges requires special care due to the nature of the material involved; damage may not be readily apparent until after a large load has been applied, at which point it may not be possible to repair the bridge without replacing part of it. In addition, certain species of wood are susceptible to insect attack, especially if the bridge is located near its natural habitat.
Steel and concrete are the most often used materials for contemporary bridge building. Wood, iron (a distinct sort of steel), plastic, and stone are among the other materials. Prior to the availability of steel and concrete, the majority of bridges were constructed of wood, rope, and/or stone. In some cases, when there is no suitable rock available, they are made from masonry.
The type of material used to build a bridge affects its cost and how long it will last. For example, a wooden bridge will cost more up front but will last much longer than a metal one of equal size. A stone bridge is very expensive to build but will last forever if cared for properly.
When choosing a material for your bridge, consider its appearance, durability, expense, and ability to accommodate vehicles and traffic flow. Wooden bridges are popular because of their affordability and adaptability to different shapes and sizes of crossings. Their major drawback is that wood gets old-looking quickly when exposed to the weather. Also, wooden bridges are more likely to suffer from insect damage and disease.
Concrete is by far the most durable of all bridge materials. It is hard to destroy chemically and almost impossible to burn. The main problem with concrete bridges is that they are expensive to make compared to other options and lack flexibility for different crossing types.
Wood, stone, iron, and concrete have been the four basic materials utilized building bridges. Iron has had the largest impact on modern bridges. Steel is created from iron, and steel is used to make reinforced and prestressed concrete. Concrete is by far the most common bridge material, accounting for 95% of all bridges.
Wood was the original bridge material because it is strong, easy to work with, and available in the region where roads were being built. Until the late 18th century, wooden bridges were the only kind of bridge available. As cities grew and traffic increased, so did the need for different types of bridges.
Stone was the next bridge material to be developed. The ancient Greeks are known to have used stone bridges, but it wasn't until much later that they were again used extensively in Europe. By the 17th century, when many new bridges were needed, there was a shortage of stone. So, builders turned to using wood instead. However, after many incidents where stones bridges proved too costly to replace, the use of stone bridges once more became popular. Today, almost all countries have some type of infrastructure project or plan in progress or completed recently. These projects often include the construction of new bridges. Some countries like China build hundreds of new bridges every year!