Are you familiar with popular bridges? Perhaps you know of the famous Brooklyn bridge or others spread across many cities in the world. Smaller-sized bridges made with wood may be a familiar sight for people in rural areas or third-world countries. Whatever the case, bridges in every place serve the same purpose. Sometimes a bridge is placed over water to connect one part of a road to another. Or when the surface beneath is rough & unusable. While a bridge is mainly used over water bodies in ancient times, there is more use for it nowadays. In some cities, the bridge connects roads on highways or within the city center even when there is no water body. It’s also a new way of easing traffic, among other things.
However, before bridges were built with concrete and iron, wood or stones were the major materials used thousand years ago. How has the construction of bridges evolved over the years? Let’s see how it started and what the present design of bridges has become.
Stone Age
The earliest humans had difficulty crossing water bodies. With little to no technology, they were restricted when it came to crossing water. As for saturated areas, the ancient world found a way to walk such land areas using stone bridges. Popular as stepping stones, this 6,000-year-old technique was common in England and a few places. Solid stones, especially rocky ones, were placed on marshy grounds to enable people to walk over them. The stones form a solid surface, preventing people from sinking into the mud. This must have worked for a period. However, it had limitations. When people wanted to move from one location to another over a body of deep water, then putting stones on the floor wasn’t a good option. In fact, it didn’t work. So, humans advanced and devised a new method — the use of logs/ trees.
Wooden Bridges
The earliest form of wooden bridge was simply a fallen tree placed over a river or lake. One part of the tree is placed on the side of the road, and another side is at the other end. This allows people to walk over the log of wood. At times, the wood used is fallen trees. Sometimes later, trees intentionally fell to be used as a bridge.
For example, the bridge in upper Lake Zürich, Switzerland, is made of timber. The use of wooden bridges also evolved. The ancient city of Rome improved the wood bridges using well-cut and shaped wood. And sometimes, later, the technology of wooden brides was upgraded. At this time, like the popular bridge constructed by Puspagupta in India, chains were introduced in bridge construction. The chain held the wood together firmly to give resistance against flood.
The history and evolution of wooden bridges continued for centuries. Later, the use of nails and screws was introduced as reinforcement. Although modern structures have replaced a good number of wooden bridges, some have been retained for cultural and aesthetic values.
Iron and Concrete
In the early 1900s, iron bridges started to become popular. Stefan Bryła is one of the first set of people to be associated with constructing welded bridges. Iron bridges were more reliable than wooden types. Strength and durability were the major benefits of this evolution. And it was on this improvement that bridges were built for the next 50 years. New designs of bridges were constructed with a mixture of steel and concrete. Engineers developed intricate designs to ensure stability, durability, and strength while paying attention to aesthetics. The goal of bridge designers now goes beyond “simply building.” Attention to architectural design is now important. Little wonder many, many bridges across Europe, Asia, and America are more than just a means of movement — many have become tourist attractions. The new approach to bridge construction focuses on the use of concrete and steel. Steel is mixed with concrete to create pillars that serve as a foundation for the bridge and are also used as cables to hold the entire structure in place.
Advanced research has also helped in terms of knowing the weight bridges can bear and constructing with expansion in mind. So this enables builders to take necessary measures that guarantee safety at all times.
Maintenance
Part of bridge construction is maintenance. Like every type of construction, bridges need maintenance to keep standing. A bridge is periodically examined to ascertain its condition and arrange necessary fixes.
Bridge construction is by no means an easy task. It requires precision and meticulous effort. First, engineers have to study the location before a bridge is erected. Lots of calculations and plans priced the actual building process. During the building process, monitoring is essential to ensure things are going as planned. So not only has the goal of a bridge changed significantly over the years, the method of construction has changed too.