How were ancient bridges built?

Method:

The cofferdam construction method for bridge foundations appeared in the Roman era, that is, driving wooden piles to form a cofferdam, pumping water and building bridge foundations and piers in it; in China in the 11th century When the Luoyang Bridge was first built, stones were thrown all over the river at the bridge site in the early stages of the construction process. Oysters were cultured on them and then cemented to form a raft-shaped foundation after two or three years. This reflects the wisdom of the working people of ancient China.

With the emergence of steel and cement around the 18th century, the development of materials and advancements in engineering technology injected new vitality into bridge technology. The bridges of this period are called modern bridges. The world's first cast iron bridge was the Severn River Bridge built by the British Colebrookdale Factory in 1779. The bridge was a semicircular arch consisting of five arch ribs with a span of 30.7 meters.

In addition to the static force represented by bearing capacity, the mechanical principles in bridge design have gradually become an important part of the attention of personnel, especially the research and development of bridge wind resistance design. For example, the Niagara Falls road and rail bridge uses wrought iron cables and stiffening beams; the Brooklyn Suspension Bridge in New York uses stiffening trusses to reduce vibrations; the Golden Gate Bridge in San Francisco and the Oakland Bay Bridge are also suspension bridges that use stiffening beams.

Extended information

The progress of basic materials theory has also actively promoted bridge engineering into a new era, such as the emergence of reinforced concrete bridges. Reinforced concrete is the part where steel bars are embedded in the tension zone of the concrete, allowing the two to work together to receive the same force.

During the stress process, the steel bars resist tension and the concrete resists pressure, working together to greatly increase the load-bearing capacity of the structure. Therefore, in the two to thirty years after 1900, a large number of reinforced concrete arch bridges and beam bridges appeared.

People's Daily Online - What is the difference between building bridges in ancient and modern times