Bridges are built over roads, rivers, or railways. They appeared a long time ago. Back then, they were built with stones, wood, iron and so on. Some were very simple, like a footbridge made out of a big tree. But today, bridges are bigger, stronger, and more modern. This is because we have better technology today.
Bridges are a mix of maths, physics and architecture(建筑学). They are finished by skilled engineers and they take years to build.
Bridges must be strong enough to support not only their own weight, but also the weight of the people and cars. They must last a long time and be built in a way that protects them from earthquakes, strong winds and freezing. Now let's see two main types of bridge.
Arch Bridges(拱形桥) were invented a long time ago by the Romans. They were built out of stone and in the shape of arches. Suspension bridges (悬索桥)are more modern, with the first ones being built in the early 19th century.
The oldest bridge in the world is the Zhaozhou Bridge in China. It's an arch bridge made out of stone that was built in 605A. D. But if you're looking for one of the most beautiful and famous bridges, it would be the Golden Gate Bridge in San Francisco. It's a suspension bridge built in 1937. It has a length of 2.78 kilometres. If you think that's long, you should see the Danyang-kunshan Grand Bridge in China. It's over 164.85 kilometres long! It's the world's longest bridge.
| Bridges | |
| Main introduction | Bridges have a long People use different to build bridges The science and technology mix maths, physics and architecture |
| What's the most important | The bridges must be strong enough to support the people, cars and . |
| Two main | Arch bridges and suspension bridges |
| Fun facts | The Zhaozhou Bridge is famous as the oldest arch bridge. The Golden Gate Bridge is a suspension bridge built in 1937. The Danyang- kunshan Grand Bridge is the one in the world. |
