The Architectural Structure of Zhao Zhouqiao

This bridge is a hollow circular stone arch bridge, which is the earliest and best preserved giant stone arch bridge in China. Zhao Zhouqiao is the first open-shouldered stone arch bridge to be selected into the world record association Book of World Records, which is the best in the world. Zhao Zhouqiao, Cangzhou Iron Lion, Dingzhou Kaiyuan Temple Pagoda and Zhengding longxing temple Bodhisattva are called "Four Treasures of North China" by Hebei folks.

The bridge is 50.82 meters long, 37.02 meters across, 7.23 meters high and 9.6 meters wide at both ends. The design of the bridge completely conforms to scientific principles, and the construction technology is even more ingenious. Zhang said in the Tang dynasty that it was "made strangely, and people don't know why." The characteristics of this bridge are:

1. The whole bridge has only one big arch, 37.4 meters long, which was the longest stone arch bridge in the world at that time. Bridge opening is not an ordinary semicircle, but like a bow, so there is no steep slope on the road above the big arch, which is convenient for horses and chariots to get up and down.

Second, there are two small arches on the shoulders of the big arch. This is a very creative design, which not only saves stones and reduces the weight of the bridge, but also increases the water flow in bridge opening and reduces the impact of floods on the bridge when the river surges. At the same time, add an arch on the arch to make the bridge more beautiful.

Three, the big arch is composed of 28 arch rings, just like so many arches with the same shape are put together to make an arc bridge opening. Each arch ring can independently support its weight. If one arch ring is broken, the other arches will not be affected.

Fourth, the structure of the whole bridge is symmetrical, which is very harmonious with the surrounding scenery; The stone pillars and slabs on the bridge are also beautifully carved. Zhang Kun of the Tang Dynasty said that looking at the bridge from a distance is like "the clouds rise at the beginning of the month, and Changhong draws a stream". Zhao Zhouqiao's superb technical level and immortal artistic value fully show the wisdom and strength of our working people. Zhao Zhouqiao's design concept and exquisite workmanship are not only second to none among ancient bridges in China, but also according to the research on bridges in the world, open-shouldered arch bridges like this did not appear in Europe until the middle of19th century, which was later than China 1200 years ago. 1979 in may, a joint investigation team composed of four units, including the natural history group of China academy of sciences, investigated the bridge foundation in Zhao Zhouqiao. The weight of Zhao Zhouqiao is 2,800 tons, and its foundation is only a abutment with a height of1.56m made of five layers of stones, directly built on natural sand and gravel.

Such a shallow abutment is unbelievable. When Mr. Liang Sicheng inspected 1933, he thought that it was only a diamond wall to prevent water erosion, but not the foundation to bear the full load of the bridge ticket. He wrote in the report:

"In order to measure the coupon base, we dug at the foot of the coupon in the north, but about 70-8 1 cm below the riverbed, that is, we found a stone wall lying flat under the coupon. Stone * * * has five floors, and the height of * * * is1.58m. Each floor is slightly higher than the upper one, and there is no solid foundation below. Obviously, it is just a diamond wall used to prevent water erosion, not a foundation bearing the full load of bridge vouchers. Because water will be seen in another 30-40 cm, unless it is excavated on a large scale, it is really impossible to reach the bridge foundation position that we theoretically speculate. " Its structure still follows Zhao Zhouqiao, but the number of small arches on the main arch is increased to five on one side, and there are wheel marks and knee marks on the bridge.

Mao Yisheng, a Chinese bridge scientist, also mentioned it in The Stone Arch Bridge in China.

Zhao Zhouqiao was founded in 605 AD, more than 65,438+0,400 years ago. It experienced 10 floods, 8 wars and many earthquakes, especially17.6 Xingtai earthquake on March 8, 966. Zhao Zhouqiao is only over 40 kilometers away from the epicenter and has not been damaged. Mao Yisheng, a famous bridge expert, said that no matter what the internal structure of the bridge is, only it can exist 65,438+. 1963 The flood flooded the arch of the bridge. According to the local old man, standing on the bridge can feel the bridge body shaking greatly. According to records, Zhao Zhouqiao has been restored nine times since its establishment.

(Remarks: During the restoration process, the bridge-building materials damaged in historical years were sorted out and collected, and most of them were stored in the museum of Zhao Zhouqiao Scenic Area. ) This is a major improvement made by Li Chun on the arch shoulder, which changed the solid shoulder arch used in the previous bridge construction into an open shoulder arch, that is, two small arches were set at both ends of the big arch, and the clear distance of the small arch near the foot of the big arch was 3.8 meters, and the clear distance of the other arch was 2.8 meters. This kind of open-shouldered arch with large arch and small arch has excellent technical performance. First, it can increase the flood discharge capacity and reduce the impact of flood on bridges due to the increase of water volume in flood season. The flood potential of Gujiao River in flood season is great, which is a test for the flood discharge capacity of the bridge. Four small arches can share part of the flood. According to the calculation, the four small arches increase the water area by about 16%, which greatly reduces the impact of flood on the bridge and improves the safety of the bridge.

Secondly, compared with the solid shoulder arch, the open shoulder arch can save a lot of earthwork materials and reduce the dead weight of the bridge. According to calculation, four small arches can save 26 cubic meters of stone and reduce the dead weight by 700 tons, thus reducing the vertical pressure and horizontal thrust of abutment and bridge foundation on the bridge body and increasing the stability of the bridge. Thirdly, the beautiful shape is added. The four small arches are balanced and symmetrical, and the big arch and the small arch form a complete picture, which is lighter and more beautiful, reflecting the complete unity of architecture and art. Fourthly, according to the theory of structural mechanics, the open-shouldered arch structure makes the bridge in a favorable position when bearing load, which can reduce the deformation of the main arch ring and improve the bearing capacity and stability of the bridge. In the traditional construction methods in ancient China, long bridges are usually in the form of multiple holes, so that each hole has a small span, a gentle slope and is easy to build. However, porous bridges also have disadvantages, such as many piers, which are not conducive to the navigation of ships and hinder flood discharge; The pier has been impacted and eroded by the current for a long time, and it is easy to collapse over time. Therefore, when designing this bridge, Li Chun adopted the form of single hole and large span, and no pier was erected in the middle of the river, which made the stone arch span as long as 37 meters. This is an unprecedented initiative in the history of Chinese bridges.