In September of the forty-fourth year of Emperor Kangxi in Qing Dynasty (1705), Emperor Kangxi ordered the construction of the first bridge on the Dadu River in order to unify the whole country and solve the problem that the road leading from Han area to Tibetan area was blocked.
Based on the principle of cable crossing, thick bamboo ropes are tied on both sides, each bamboo rope is threaded with a short bamboo tube, then the chain is tied on the bamboo tube, and then the rope on the bamboo tube is pulled from the other side to pull the bamboo tube and the chain to the opposite side. After the chain was pulled, the craftsmen made great efforts to tighten the chain and anchor it firmly, so that the bridge could bear enough pressure and maintain a strong safety factor.
This bridge is123.42m long, 3m wide and10m high. The whole bridge consists of 13 thick iron cables, of which 9 iron cables are placed side by side at the bottom as load-bearing; The four ropes on both sides are connected with the bottom rope through hook screws, which serve as handrails on both sides and play the role of insurance.
The average length of each iron cable of Luding Bridge is127.47m, and its weight is 1.5 to 2 tons. Each iron wire has 890 flat rings on average, 13 iron wires * * have 1 157 1 flat rings; The length of the flat ring is about 19 cm, the outer diameter is 9 cm and the inner diameter is 3 cm. The firmness of the iron cable of Luding Bridge lies in the strength of the iron parts, and the strength of the forged iron parts smelted by this indigenous method is still relatively high.
This big project took about a year to complete completely, and it took a lot of manpower and material resources. Since then, Luding Bridge has also been oxidized, rusted and broken. Later, people processed and strengthened it.
Extended data
Classification of bridges
Bridges are extensions and connections of roads. It is a water beam, an air road, a land node or a hub. It has the functions of pedestrian loading, safety and convenience, and smooth traffic. In short: "A bridge is a passage across obstacles".
Regarding the classification of bridges, if the main materials are used to build bridges, they can be different from wood, stone, brick, bamboo, rattan and iron. If divided by bridge type, it can be roughly divided into beam bridge, arch bridge, suspension bridge, cable-stayed bridge, etc.
Beam bridge—
This is the most basic type of bridge. It is formed by placing a beam (bridge deck) on a column or pier, and it is a bridge with the bending of the main beam as the load-bearing component. It can be divided into Liang Shi bridge, wooden beam bridge, steel beam bridge and concrete beam bridge, and single span and multi-span. Such as Luoyang Bridge and Wuli Bridge in ancient times; Modern Qiantang River Bridge and Third Bridge, Yangtze River Bridge in Wuhan and Nanjing, overpass in Beijing, etc.
Arch bridge—
It is composed of pier, arch sheet and bridge deck, and it is a load-bearing structure with arch members between pier and abutment. According to materials, there are brick arch bridges, stone arch bridges, concrete arch bridges, reinforced concrete arch bridges and steel arch bridges. According to the position of the bridge deck, there are bridge deck type and half-through type; There are also single holes and porous ones. Zhao Zhouqiao is a single-hole stone arch bridge, and Lugou Bridge is a porous multi-arch stone bridge, and they are all through; Shanghai Lupu Bridge is a half-through steel arch bridge.
Suspension bridge-
Also known as suspension bridge and cable bridge. It consists of cable tower, anchor ingot, front view, suspender and bridge deck (beam). This kind of bridge is very capable of crossing rivers and bays in one span. In ancient times, such as Luding Bridge, in modern times, such as Humen Bridge in Guangdong and Runyang Yangtze River Bridge.
cable-stayed bridge
It consists of main girder, bridge tower and stay cables. As a cable system, it has greater spanning capacity than a beam bridge and is the main bridge type of long-span bridges. The pylon types of cable-stayed bridges are A-type, inverted Y-type, H-type and single-column type, and the materials are steel and concrete. Stay cables are arranged with single cable plane, parallel double cable plane and stay cable plane. Such as Sutong Bridge in Jiangsu and Hangzhou Bay Bridge in Zhejiang.
Baidu encyclopedia-Luding bridge
China News Network-Why does Zhao Zhouqiao become a "strong bridge"? After 10 floods and 8 wars.