Zhaozhou Bridge

Zhaozhou Bridge

Zhaozhou Bridge is a stone arch bridge located on the South River of Zhaoxian County, Shijiazhuang City, Hebei Province. It is named after Zhaozhou County in ancient times. Local people call it Dashiqiao, which is different from Yongtong bridge (xiaoshiqiao) outside the west gate of the city. Zhaozhou Bridge was built in the Sui Dynasty, designed and built by Li Chun, a craftsman. Later, it was given the name of Anji bridge by Zhao Xu, the emperor of Song Dynasty, and its name was changed.

Zhaozhou Bridge is the world's oldest, largest span and best preserved single span open shouldered stone arch bridge. Its construction technology is unique. It is the first "open shouldered arch" structure in the world's bridge history, and has high scientific research value. Its carving technique is vigorous and powerful, and its artistic style is novel and bold, showing the rich, neat and elegant stone carving style of Sui Dynasty, and its bridge body is decorated with carved patterns It has high artistic value. Zhaozhou Bridge occupies an important position in the history of Chinese bridge construction, and has a far-reaching impact on the bridge construction of future generations all over the world.

On March 4, 1961, Anji bridge (Dashiqiao) was announced as the first batch of national key cultural relics protection units by the State Council of the people's Republic of China.

In 2010, zhaozhouqiao scenic spot was rated as national AAAA scenic spot.

Historical evolution

Zhaozhou Bridge was built in Sui Dynasty

Designed and built by Li Chun, a craftsman, it has a history of more than 1400 years.

In July of 792, Zhaozhou Bridge was repaired for the first time. According to Liu Chaoran's records of newly built stone bridge, 200 years after the bridge was built, the diamond wall on the west side of the north side of the bridge was damaged by the flood, and the abutment sank, which made the row (small arch) inclined and cracked. By using the method of mending stone and rebuilding, the original state was restored, and the fence and pillar were copied, so as to restore the appearance and make the bridge strong.

In 1066, Zhaozhou Bridge was repaired for the second time. According to the history of the Song Dynasty, in the third year of song Zhiping (1066), due to the corrosion and falling off of the chiseled iron, the outer arch was stolen, which made the outer arch incline, so the workers righted and restored it.

From 1562 to 1563, Zhaozhou Bridge was repaired for the third time. Due to the long-term rolling of the bridge deck stone by vehicles, the "frog track" is very deep, uneven and inconvenient to drive. A new deck stone was laid to complete the battle.

In 1563, Zhaozhou Bridge was repaired for the fourth time. It mainly renovated the South and North docks and the column base of the railings, and imitated the dragon and beast patterns carved on the original railings and watchposts. In addition, it added some new story exhibitions. In the same year, Zhaozhou Bridge was repaired for the fifth time. Due to the fire cooking of the boat under the bridge, the gap between the bridge stones was repaired and the waist iron was strengthened.

In the autumn of 1597, Zhaozhou Bridge was repaired for the sixth time. After years of rolling, the bridge deck was damaged. Construction started in autumn and finished in winter.

In 1821, Zhaozhou Bridge was repaired for the seventh time.

In the spring of 1933, Liang Sicheng, a bridge expert of China construction society, made a detailed survey and mapping of Zhaozhou Bridge, and wrote the article "Zhaozhou Dashi bridge is Anji bridge".

In the winter of 1952, the winter of 1953, the summer of 1954 and February of 1955, the administration of cultural relics of the Ministry of culture and other units successively sent experts and scholars to excavate and survey the Zhaozhou Bridge four times.

In 1955, the repair project of Zhaozhou Bridge began.

In 1958, the repair project of Zhaozhou Bridge was completed for the eighth time. The repair of Zhaozhou Bridge carried out a comprehensive survey and repair, the whole project uses the original arch stone, hook stone, waist iron, iron rod and points five methods, also set up two sticky three oil waterproof layer (two layers of waterproof linen and three layers of asphalt) above and below the bridge deck to prevent water leakage and corrosion. All the railings and watchboards of the bridge deck shall be made according to the early style.

Architectural features

Site selection characteristics

The reasonable site selection of Zhaozhou Bridge is an important reason why it has become a millennium old bridge. Li Chun chose the base site of Zhaozhou Bridge in the coarse sand of He river because taking the coarse sand as the foundation can enhance the bearing strength of the bridge and ensure the stability of the bridge.

Modern survey shows that the stratum distribution of Zhaozhou Bridge site is stable, the foundation soil is mainly dense silty clay, with silt and sand interlayer in the middle, which is an ideal place to build this kind of super long span single hole bridge. According to the laboratory analysis, the basic bearing capacity of this soil layer is 34 T / m2, and the compressibility of the clay layer is small, so the sand liquefaction will not occur during the earthquake, so it is a good natural foundation. Its stable foundation is one of the important reasons why this ancient bridge can withstand many earthquakes.

The abutment of Zhaozhou Bridge is low arch foot, shallow foundation and short abutment. It is built directly on the natural sand and stone, and on this basis, the abutment is built with 5 layers of stone strips, and each layer is slightly higher than the previous layer.

Structural features

1、 Open spandrel arch: two symmetrical small arches are built on each of the two spandrels, which lie on the shoulders of the main arch. In accordance with the principle of structural mechanics, the drainage area is increased by 16.5%, and the stone material is saved.

2、 Large span, arc flat: take the form of single hole long span, no pier in the river center; arc arch form, stone arch height reduced. It is better than the multi span bridge with small span and many piers, which is not conducive to flood discharge.

3、 Wide at both ends and narrow in the middle.

4、 Vertical parallel masonry method.

Construction technology

During the construction of Zhaozhou Bridge, the hard blue gray sand and stone produced by nearby counties were selected as the stone materials

In order to reduce the height of stone arch, arc arch is adopted. The net span of the main span is 37.02m, while the arch height is only 7.23m, and the ratio of arch height and span is about 1:5. Thus, the dual purposes of low bridge deck and large span are realized.

In the construction of Zhaozhou Bridge, the longitudinal parallel laying method is adopted, that is, the whole bridge is composed of 28 independent arches along the width direction, and each arch is laid independently, which can be flexibly constructed for each arch. Each time an arch is built, it is only necessary to move the scaffold (the temporary support used to support structural members during construction) and then continue to build another adjacent arch. If the stone of an arch is damaged, it only needs to be replaced with new stone instead of adjusting the whole bridge.

In order to strengthen the transverse connection between the arches and make the 28 arches form an organic whole with tight and firm connection, a series of technical measures were adopted in the construction of Zhaozhou Bridge

Each arch coupon adopts the method of "lower width, upper narrow, and a little score" to make each arch coupon incline inward and squeeze against each other, so as to enhance its transverse connection and prevent the arch stones from toppling outward; in the width of the bridge, the method of "small score" is also adopted to gradually shrink the bridge width from both ends of the bridge to the top of the bridge, so as to strengthen the stability of the bridge.

Five iron tie rods are evenly arranged along the bridge width direction on the main tie rod to pass through 28 arch ties, with semicircular rod heads at both ends of each tie rod exposed outside the stone to clamp 28 arch ties and enhance their transverse connection; each of the four small arches has an iron tie rod to play the same role.

A layer of arch protection stone is covered on several outer arch stones and the small arches at both ends to protect the arch stone; six hook stones are set on both sides of the arch protection stone to hook the main arch stone to make it firmly connected.

In order to make the adjacent arch stones fit closely, the "waist iron" is set between the adjacent arch stones on both sides of the main hole, and the "waist iron" is also set on the arch back of the adjacent stones between the main holes to chain the arch stones. The side of each arch stone is chiseled with fine and dense twill to increase the friction force and strengthen the transverse connection of each stone.

Cultural relics

overview

Zhaozhou Bridge is a single hole cut round open shoulder stone arch bridge, because there are two small holes in the shoulders of both ends of the bridge, so it is also called open shoulder bridge.

abutment

Zhaozhou Bridge Abutment is about 5 meters long and 9.6 meters wide. The width of the foundation is about 9.6-10m and the length is about 5.5m. The buried depth of the foundation is 2-2.5m; the thickness of the abutment is 1.549m; there are five layers of flat stones at the foot of the arch; the mortar joint is very thin and there is no crack; each layer has a slight crack; the lower layer of stone is slightly thicker than the upper layer.

bridge structure

The total length of Zhaozhou Bridge is 64.4 meters, the vault width is 9 meters, the arch foot width is 9.6 meters, the span is 37.02 meters, and the arch rise is 7.23 meters. There are two small arches at both ends of the main arch, with clear spans of 2.85m and 3.81m. The bridge body is built by 28 parallel arches, and is connected and reinforced by "waist iron" of Goushi, Shoufen, fengyao and Fushi, which improves the integrity. There are 42 balustrades and watchposts on both sides of the bridge deck, which are exquisitely carved. The "Dou Zi Juan Ye" and "Xing Long" carved on the balustrade are semicircular, with moderate proportion and smooth lines.

unearthed relic

In the winter of 1952, the winter of 1953, the summer of 1954 and February of 1955, the cultural relics administration bureau of the Ministry of culture excavated more than 1500 large and small bridge stones. After selection, it can be assembled into more complete stones with carved columns and inscriptions. Among them, there are more than 20 railings, including 2 Taotie railings of the Sui Dynasty, 7 Dragon carving railings of the Sui Dynasty, 1 zouma railings, 16 Douzi leaf rolling railings, and 1 Phoenix railings; two lion stone carvings; 52 Yangtian stone carvings, 1 bridge repair and 1 inscription of the Tang Dynasty; 2 bridge repair steles of the Ming Dynasty; 6 residual stones with inscriptions; and "immortal trace"

Chinese PinYin : Zhao Zhou Qiao