Zhao Zhouqiao was founded 1400 years ago, and experienced 10 floods, 8 wars and many earthquakes, especially 1966 Xingtai M7.6 earthquake. Xingtai is more than 40 kilometers away from here, and there is also an earthquake of magnitude 4.0. Zhao Zhouqiao was not damaged. Mao Yisheng, a famous bridge expert, said that no matter what the internal structure of the bridge is, only it can exist. 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.
Adding two small arch coupons at the upper end of the main arch coupon can save materials, reduce the dead weight of the bridge (reduce the dead weight 15%) and increase the discharge of river water under the bridge.
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 of 1.55 meters made of five layers of stones, which is directly built on natural sand and gravel.
Such a shallow bridge foundation 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 now about 70-80 cm below the riverbed, that is, we found the 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 impossible to reach the bridge foundation position that we speculate according to theory. "
In order to protect Zhao Zhouqiao, the new bridge structure built at 100m east of Zhao Zhouqiao at the end of last century still uses 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.
Edit this paragraph design innovation
(1) adopts the form of circular arch, which changes the tradition that most large stone bridges in China are semi-circular arches. The arches of ancient stone bridges in China are mostly semicircular, which are beautiful and complete, but they also have two defects: First, the traffic is inconvenient, and the semicircular arch is more suitable for small-span bridges, while the adoption of semicircular arch for long-span bridges will make the arch very high, resulting in steep bridges and inconvenient for pedestrians and cars to cross the bridge. Second, the construction is unfavorable, and the scaffolding used for semi-circular arch stone masonry will be very high, which will increase the construction risk. To this end, Li Chun and craftsmen creatively adopted the form of circular arch, which greatly reduced the height of stone arch. The net span of Zhao Zhouqiao's main span is 37. 02 meters, while the arch height is only 7.25 meters, and the arch height-span ratio is about 1:5. In this way, the dual purposes of low bridge deck and long span are realized, and the bridge deck transition is smooth, which is convenient for vehicles and pedestrians. It also has the advantages of saving materials and convenient construction. Of course, the thrust of the circular arches at both ends on the bridge foundation also increases accordingly, which puts forward higher requirements for the construction of the bridge foundation.
(2) adopt our shoulders. This is a major improvement made by Li Chun on the arch shoulder. The solid shoulder arch used in bridge construction is changed into an open shoulder arch, that is, two small arches are set at both ends of the big arch, and the clear distance between the small arch near the foot of the big arch is 3.8 meters, and the clear distance between the other arch is 2.8 meters. This kind of open-shouldered arch with large arch and small arch has excellent technical performance. First of all, it can increase the flood discharge capacity and reduce the impact of flood on bridges caused by 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, four small arches can increase the water area by about 16%, greatly reduce the impact of flood on the bridge and improve the safety of the bridge. Secondly, compared with solid shoulder arch, open shoulder arch can save a lot of earthwork materials and reduce the dead weight of the bridge. According to the 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. Third, it adds a beautiful shape. The four small arches are balanced and symmetrical, and the large 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 can make the bridge in a favorable state when bearing load, reduce the deformation of the main arch ring and improve the bearing capacity and stability of the bridge.
(3) Single hole. In the traditional construction methods in ancient China, generally long bridges often take 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.
Edit the technical creativity of this paragraph.
(1) The bridge site selection is reasonable and the bridge foundation is stable.
According to his rich practical experience for many years, after strict and careful exploration and comparison, Li Chun chose a relatively flat place on both sides of Jiaohe River to build the bridge. The stratum here is alluvial by rivers, and the surface of stratum is coarse sand layer washed by water, followed by fine stone, coarse stone, fine sand and clay layer. According to modern calculation, the stratum here can bear the pressure of 4.5 to 6.6 kilograms per square centimeter, while the ground pressure in Zhao Zhouqiao is 5 to 6 kilograms per square centimeter, which can meet the requirements of bridges. After the bridge site is selected, the foundation and abutment are built on it. So far, the bridge foundation has only sunk 5 cm, indicating that the stratum here is very suitable for bridge construction.
(2) The masonry method in Zhao Zhouqiao is novel and convenient for construction and maintenance.
Li Chun used local materials and selected hard blue-gray sandstone produced in nearby counties as the stone for building the bridge. In the stone arch laying method, the longitudinal (along the bridge direction) laying method is adopted, that is, the whole bridge is composed of 28 independent arch pieces side by side along the width direction, and the arch thickness is 1. Ozone meter. Each coupon is operated independently, and it is quite flexible. After each coupon is completely closed, it becomes an independent spell. This masonry method has many advantages, it can not only save the wood used for "scaffolding", but also facilitate movement; At the same time, it is beneficial to the maintenance of the bridge. If the stone of the arch coupon is damaged, it is only necessary to embed new stone and repair it locally, without adjusting the whole bridge.
(3) Many strict measures have been taken to keep the bridge stable.
Li Chun adopted a series of technical measures to strengthen the horizontal connection between the arches, making the 28 arches form a tight and solid organic whole. L) Each arch piece adopts the method of "dividing points" slightly, so that each arch piece leans inward and leans against each other, so as to enhance its lateral connection and prevent the arch stone from dumping outward; In the width of the bridge, a small number of "demarcation points" are also adopted, that is, the width is gradually reduced from the two ends of the bridge to the top of the bridge, from the widest 9.6 meters to 9 meters, so as to strengthen the stability of the bridge. 2) Five tie bars are evenly arranged on the main ticket along the bridge width direction, passing through 28 arch tickets, and each tie bar has a semicircular head exposed outside the stone at both ends, so as to clamp the 28 arch tickets and enhance their transverse connection. There is an iron tie rod on each of the four small arches, which plays the same role. 3) Cover several arch stones near the outside and small arches at both ends with a layer of arch stones to protect the arch stones; There are six hook stones on both sides of the arch protector to hook the main arch stone to make it firmly connected. 4) In order to make the adjacent arch stones stick together closely, the "waist iron" which plays a connecting role is inserted between the adjacent arch stones on both sides of the outer connecting piece, and the adjacent stones between the connecting pieces are also inserted into the "waist iron" on the arch back to chain the arch stones. Moreover, the side of each arch stone is chiseled with fine twill to increase friction and strengthen the lateral connection of each coupon. These measures make the whole bridge become a close whole and enhance the stability and reliability of the whole bridge.
(4) The abutment of Zhao Zhouqiao is unique.
Abutment is the foundation of the whole bridge, and it must be able to bear the huge horizontal thrust and vertical pressure of the main arch ring (bridge main body) axial force decomposition. The abutment in Zhao Zhouqiao has the following characteristics: l) the arch foot is low: the arch foot is only about half a meter below the river bed; 2) Shallow bridge foundation: the bridge foundation surface is about the arch foot1.7m; 3) Short abutment: From top to bottom, the abutment with a length of 5 meters, a width of 6.7 meters and a height of 9.6 meters is constructed with gradually slightly thickened stone strips. This is an economical, simple and practical abutment. In order to ensure the reliability of abutment, Li Chun has taken many corresponding foundation reinforcement measures. In order to reduce the vertical displacement of the abutment (that is, the subsidence caused by the vertical pressure of the bridge main body), Li Chun adopted the measures of driving many wooden stakes beside the abutment to strengthen the foundation of the abutment; This method is also often used in today's factory and bridge construction. In order to reduce the horizontal movement of the abutment (that is, the abutment moves backward due to the horizontal thrust of the bridge main body), Li Chun adopted the method of extending the back seat of the abutment to offset the horizontal thrust. In order to protect the abutment and abutment, Li Chun also set up a diamond-shaped wall along the river, which on the one hand can prevent the water from scouring, and on the other hand, the diamond-shaped wall is integrated with the abutment and abutment, thus increasing the stability of abutment. The above measures ensure that the bridge has a solid abutment and improve the stability of the bridge.
Edit this paragraph, Zhao Zhouqiao's three musts.
(1) Voucher is less than a semicircle. In China, it is customary to call bridge opening, doorway and other arc-shaped buildings "vouchers". Generally, tickets for stone bridges are mostly semicircular. However, the span of Zhao Zhouqiao is very large, with 37.04 meters from one end to the other. If the ticket face is semicircular, the height of the bridge hole is 18.52 meters. In this way, crossing the bridge is like crossing a hill, which is very laborious. Zhao Zhouqiao's certificate is an arc smaller than a semicircle, which not only reduces the height of the bridge, but also reduces the stone and labor for repairing the bridge, and the bridge body is very beautiful, much like Changhong in the sky.
(2) "Collision" is illusory. The two shoulders of the coupon are called "convex". Generally, the collision of stone bridges is made of stone, but the collision in Zhao Zhouqiao is not made of stone, but one or two arc-shaped coupons are built on each shoulder of coupons. In this way, four coupons were added to the bridge body, which saved about 180 cubic meters of stone and reduced the bridge weight by about 500 tons. Moreover, when the river rises, part of the water can flow downwards from the small ticket, which can not only make the water flow smooth, but also reduce the impact of flood on the bridge and ensure the safety of the bridge.
(3) build by laying bricks or stones. It uses 28 small tickets to form a large ticket of 9.6 meters in Zhang Kuan. But with side-by-side masonry, there is no connection between the narrow stones, which is not as strong as the column. In order to make up for this shortcoming, in the construction of Zhao Zhouqiao, nails were added between narrow stones to make them a whole. Even if a narrow ticket is broken, it will not affect the overall situation, and it is easy to repair, and it will not affect the traffic on the bridge when repairing the bridge.
Edit this Zhao Zhouqiao legend.
The immortal mark on the Zhao Zhouqiao mainly refers to the hoofprint left by the legendary Zhang riding a donkey backwards on the bridge; The driveway ditch marks and knee marks on the knees rolled by Chai Wangye's cart crossing the bridge; In order to save the stone bridge, Lu Ban jumped into the river and put his hand on the palm print of the stone bridge. These fairy tales often become one of the most interesting contents for tourists. When he came to Zhao Zhouqiao, he had to look for it first. This is the most famous legend about Zhao Zhouqiao.
According to legend, a long time ago, five miles south of Zhao County, Hebei Province, there was a big river named Yanhe. Weihe River originates from Jingxing Mountain in the west of Hebei Province. In ancient times, its water potential was great. Every summer and autumn, when heavy rain comes, rain and mountain springs flow down together, and several rivers meet along the way to form a turbulent torrent. Therefore, residents and pedestrians on both sides of the river are very inconvenient.
Lu Ban, a famous craftsman, knows the difficulties of the people in Zhao County. He came all the way here specially to show his superb technology and built this Zhaozhou Dashiqiao overnight.
Zhao Zhouqiao made good news, which soon spread to all directions. Residents from far and near came to visit in surprise. This miracle even shocked one of Zhang. In the wallet on the donkey's back, there is a "sun" on one side and a "moon" on the other side to cross the bridge. That's not enough. Zhang originally wanted to play a joke on Lu Ban. He made an appointment with Chai Rong, pushing a unicycle carrying the "Five Mountains and Famous Mountains" and came to the bridge together. He asked whether the bridge would allow them to walk at the same time. At this time, Luban just built the bridge and was very proud. He said disapprovingly, "Such a strong stone bridge can't stand you two?" Unexpectedly, after they got on the bridge, they crushed it to pieces. Seeing that the situation was not good, Lu Ban jumped off the bridge and held the east side of the bridge with both hands, so that the two immortals passed the Sun Moon and the Five Mountains smoothly. Since then, there have been several "immortals" on the bridge that people talk about; Zhang's donkey's hoofprint and the round pit pressed by his hat; Chai Rong had a knee print and a driveway ditch on one knee because of pushing the cart too hard; And the handprint of Lubanto Bridge. Later, except for the collapse of the east, the handprints were gone, and the rest of the fairy tales "survived." This vivid legend is sung in "Little Cowherd".
Edit this passage of Zhao Zhouqiao Bridge.
The first part: water passes through the jasper ring; The bottom line is: people ride on the back of the black dragon.
Edit this paragraph of the Zhao Zhouqiao Principles.
Zhao Zhouqiao, also known as Anji Bridge, is located 45 kilometers southeast of Shijiazhuang, on the Jiaohe River in the south of Zhao County. Because the bridge body is all made of stone, it is commonly known as Dashiqiao. It was built between Emperor Kai of Sui Dynasty and Daye, and was supervised by craftsman Li Chun. Zhao Zhouqiao has a novel structure and beautiful appearance. The ancients said that it was "a miracle made, and people don't know why." The bridge is 64.4 meters long, 9.6 meters wide and 37.02 meters across. It is a single-hole arch bridge composed of 28 relatively independent arches. Zhao Zhouqiao's greatest scientific contribution is his pioneering work of "open-shouldered arch". On the two shoulders of the arch, there are four parallel small holes, which not only increase the water passage, reduce the weight of the bridge, save the stone, but also enhance the stability of the bridge. This effectively ensures that in the history of 1400 years, Zhao Zhouqiao has withstood many floods, eight major earthquakes and the weight of vehicles, and still stands on the Weihe River.
There are many beautiful legends about the architecture in Zhao Zhouqiao. In the past, when the river flooded, people had to rely on wooden boats to ferry. Lu Ban, the founder of the carpenter, turned sheep into stones and built the bridge overnight. Zhang and Chief Chai came to inspect the bridge together. Zhang rides a donkey with his head down, and the sun and the moon are on the donkey's back; Officer Chai pushes a cart carrying the Five Mountains. Walking in the middle of the bridge, the bridge is crumbling. Seeing that the situation was not good, Lu Ban jumped into the water and held the bridge with both hands. This stone bridge is safe and sound. Up to now, there are clear donkey hoof prints, driveway grooves and knee prints on the bridge; Lu Ban's handprint was left at the bottom of the bridge. As the folk song "Little Cowherd" sings: "The stone bridge in Zhaozhou is repaired by Lu Ban, and the sage in the jade railing stays; Zhang rode on the donkey bridge, and the king of Chai County pushed the car and ran past the ditch.
Zhao Zhouqiao only used a single-hole stone arch to cross the Weihe River. Because there is no pier, it not only increases the drainage function, but also facilitates the communication between ships. The stone arch spans 37.7 meters and connects the south and north bridges (both ends of the bridge are nearly horizontal), with a total length of 50.82 meters. Taking such a huge span was an unprecedented initiative at that time. The stone arch has a large span, but the arch vector (the height from the connecting line between the two feet of the stone arch to the vault) is only 7.23 meters. The ratio of arch vector to span is about 1 5. It can be seen that the height of the bridge is much smaller than the radius of the arch arc, and the whole bridge body is just an arc. Such an arch is called a "flat arch". The flat arch reduces the slope of the bridge and is convenient for pedestrians and horses. What's more, there are two small stone arches on the two shoulders of the big stone arch, which has changed the traditional architectural style of filling large arch rings with sand and gravel in the past and created the world's first "split-shoulder arch" and a new bridge type. This is an amazing scientific invention, and its advantages are as follows: First, it reduces the weight of the bridge and saves the materials for filling the abdomen. After calculation, the cavity left by four small stone archways can reduce the filler 180 cubic meters, more than 700 tons. This not only saves labor and materials, but also reduces the net weight of the bridge 15.3%, thus reducing the pressure of the stone bridge on the foundations on both sides, correspondingly increasing the safety factor of the bridge 1 1.4%, and prolonging the service life of the bridge. In addition, make full use of the "passive pressure" generated by the small arch on the large arch, thus greatly enhancing the stability of the bridge. Second, the four holes left by the four small arches increased the drainage area by 16.5% during the flood season. The water area under the bridge is increased, which reduces the impact of flood on the bridge body. Third, add two pairs of small arches above the big arch, which is balanced and symmetrical, giving people a light aesthetic feeling. This exquisite shape makes Zhao Zhouqiao more magnificent.
Secondly, Zhao Zhouqiao's construction plan is extremely scientific and ingenious. There are two masonry methods for building arch holes, one is horizontal joint masonry method, and the other is vertical parallel masonry method. The arch hole of transverse joint masonry is a whole and relatively strong, but this masonry method needs to build a large wooden frame, and the whole arch hole must be completed before the wooden frame can be removed, which has a long construction period. The longitudinal parallel masonry method is to combine the whole bridge with 28 independent arches along the width direction. Each arch ticket is built separately, and it is self-contained after closure. After building an arch in this way, move the wooden frame bearing the weight of the arch coupon, and then build adjacent arches one by one. The advantage of this masonry method is that it not only saves scaffold materials, but also facilitates the construction of mobile scaffolding alone and facilitates future maintenance. Because each arch can bear heavy pressure independently, 28 arches are combined into a large arch. If an arch ticket is damaged, it can be partially repaired without affecting the safety of the whole bridge. However, the vertical parallel masonry method lacks the connection between parallel arches, and the overall structure is not firm. When building Zhao Zhouqiao, Li Chun fully considered the contradiction between river conditions and construction progress, and boldly adopted the vertical parallel masonry method. Under the production level at that time, it was impossible to build this big stone bridge in a short time. However, if the Weihe River dries up in winter and rises in summer, the project will be halfway through. In case of flood, the wooden frame and the built part will be washed away. But even in case of flood, the vertical parallel masonry method will not be greatly affected. In order to overcome the shortcomings of vertical parallel masonry method, Li Chun first used nine iron beams with caps at both ends to cross the arch back, and connected 28 arch pieces in series to strengthen the horizontal connection. Clamp it with a double silver ingot waist iron, and then there are six hook stones on each side of the bridge, which are 1.8 meters long and extend outward and downward for five centimeters, hook the main arch joint, and there are arch protection stones outside the arch joint, so that the whole bridge body is integrated. In addition, a small number of "gathering points" with the arch foot 0.6 meters wider than the vault are used to prevent the arch coupon from tilting. After more than 350 years of inspection by/kloc-0, it is proved that this construction scheme is extremely scientific and effective.
Zhao Zhouqiao's story is very touching, but why are there these marks on the bridge? Luo Ying, a modern bridge expert, said that according to the engineering principle, these signs are both driving indicators and engineering indicators. Because Zhao Zhouqiao is built by vertical parallel masonry method, the bridge will be easily damaged if both sides bear heavy loads. The donkey's hoof prints of the bridge deck factory are all at the position of 1/3 on the east side. In other words, if the heavy-duty bridge is too close to the side, the stone arch coupon is easy to deform and lean out, so it should be in the middle. The palmprint on the belly of the bridge should be an engineering index, which means that if cracks appear on the bridge, they can be temporarily supported at the palmprint to avoid immediate collapse and can be repaired calmly.
In a word, Zhao Zhouqiao embodies the wisdom of ancient craftsmen in China. A large open-shouldered stone arch bridge as old as Zhao Zhouqiao. For a long time, it was unique in the world. In Europe, in the14th century, a similar shoulder-shaped Sylar bridge appeared on the Cote River in France, which was more than 700 years later than Zhao Zhouqiao and was destroyed as early as 1809. Li Chun was a famous stonemason in Sui Dynasty, who made great contributions to bridge construction in the world.
Attachment: Anji Bridge in Hengshui, Hebei Province
Anji Bridge, a seven-hole stone arch bridge across Fuyang River, is116m long and 7' 5m wide. There are 60 stone pillars on both sides of the bridge, carved by stone lions, with vivid images and different postures. Under each lion, there are 1-2 little lions in Lotus constellation. The pier diversion platform is piled with stones, and bridge opening is carved with faucets. The whole building is integrated, magnificent and exquisite.
Anji Bridge was built in May of the 30th year of Qing Qianlong (1765) and was named "Anji" by Emperor Qianlong, hence the name Anji Bridge. 1937 There was a flood, and the middle hole was blown up by the Japanese invaders. It was repaired with wood on 1956. 1in April, 1982, the regional highway engineering team began to reinforce the middle hole of the stone bridge and repair the cement pavement. 1989 was designated as a municipal cultural relics protection unit in May.