How were many stone arch bridges built in ancient times?

Take Zhaozhou Bridge as an example.

There are two kinds of masonry methods for masonry arches, one is the transverse masonry method, and the other is the longitudinal parallel masonry method. The arch of transverse masonry is a whole, relatively strong, but this masonry method needs to build a large wooden frame, and the whole arch must be completed to dismantle this frame, and the construction period is longer. The longitudinal parallel masonry method is to combine the entire bridge along the width with 28 independent arches.

Each arch is built separately, and it is self-contained after closing. After building an arch in this way, move the wooden frame that bears the weight of the arch, and then build an adjacent arch, one by one. The advantage of this masonry method is that it not only saves the material of building the wooden frame, but also is convenient for moving the wooden frame to be constructed separately, and it is easy to maintain in the future.

Because each arch can bear the weight independently, 28 arches are spelled together into a large arch, if a certain arch is damaged, it can be partially constructed and repaired, without affecting the safety of the entire bridge. However, the longitudinal juxtaposition masonry method, the lack of connection between the juxtaposed arches, and the overall structure is not strong. When Li Chun built the Zhaozhou Bridge, he boldly adopted the longitudinal parallel masonry method because he fully considered the contradiction between the hydrological conditions of the river and the construction progress.

At the level of production at that time, the construction of this large stone bridge could not be completed in a short period of time. In order to overcome the shortcomings of the longitudinal parallel masonry method as a whole, Li Chun first used 9 iron beams with caps at both ends to traverse the back of the arch, connected 28 arch coupons in series, strengthened the horizontal connection, and then stuck the two adjacent arch stones with double silver ingot-shaped waist iron, and then on both sides of the bridge each had a length 1 8 meters, six hook stones that extend five centimeters downwards outside, hook the main arch coupon, and there are arch protection stones outside the arch coupon, so that the whole bridge body is combined. In addition, a small amount of "points" with the arch feet 0 6 meters wider than the vault are used to prevent the arch from tilting.

After more than 1,350 years of testing, it has been proved that this construction scheme is extremely scientific and effective.

Compare it to the world map, and it is roughly clear.

1. Column number: This is a stone arch bridge with a long history, probably thousands of years old.

2. For example, it is a stone arch bridge with a long history, and the hole of the stone arch bridge is arc-shaped like a rainbow.

3. Example: This is a stone arch bridge with a long history, which is incomparably majestic.

Giving practical examples to illustrate things and making the things to be explained concrete so that the reader can understand them is called an example. To illustrate things or facts by giving examples, we should pay attention to the representativeness of the examples and the appropriateness of the examples.

Illustrate in different ways that this is a characteristic of a historic bridge.

Before the masonry arch ring, the masonry procedure of the arch ring should be designed according to the span, sagittal height, thickness and arch frame, and when masonry, the deformation observation joint must be set, and the deformation of the arch should be observed at any time, and the masonry procedure should be adjusted if necessary to control the deformation of the arch ring.

The arch circle with a span diameter of less than or equal to 10m, when built with a full-cloth arch masonry, can be symmetrically and evenly built in the direction of the arch from both ends of the arch foot, and finally the arch capstone is built. When using arch arch masonry, it is advisable to build the arch foot and the vault section in sections and symmetrically, and then build 1 4 span sections.

The arch ring with a span of 10 20m, no matter what kind of arch is used, each half span should be divided into three sections of masonry, first build the arch foot section and the vault top section, and then build 1 4 span diameter section, and the two half spans should be carried out symmetrically at the same time. When the inclination angle of the arch section of segmented masonry is greater than the friction angle between the block and the template, the support should be temporarily arranged on the lower side of the arch section to avoid the slippage of the arch section.

The arch ring with a span diameter greater than or equal to 20m is generally built by a combination of segmented masonry or a combination of segmented rings and segments, and a certain amount of pressure should be added to the arch if necessary. When the ring is divided into masonry, the masonry of the lower ring should be closed and the strength of the mortar of the masonry joints reaches more than 75% of the design strength, and then the upper ring should be built.

For the masonry of the arch ring of the porous continuous arch bridge, the influence of the continuous arch should be considered, and the corresponding masonry procedures should be formulated.

Sui Dynasty.

The oldest surviving stone arch bridge in the world is the Zhaozhou Bridge, designed and built by Li Chun, an outstanding craftsman of the Sui Dynasty. The bridge is designed with a large span, a gentle bridge deck, easy traffic, and beautiful shape. It was built more than 700 years earlier than Europe.

On March 4, 1961, Anji Bridge (Dashiqiao) was announced by the People's Republic of China as the first batch of national key cultural relics protection units. In 2010, Zhaozhou Bridge Scenic Area was rated as a national AAAA-level tourist scenic spot.

Travel traffic information

1. External traffic

Tourists from other cities can take the train or high-speed rail to Shijiazhuang Railway Station, Shijiazhuang Station take Zhaohao to take bus No. 215 to Nanjiao Bus Station, Nanjiao Bus Station has a bus to Zhao County.

2. Internal transportation

After taking the bus at Nanjiao Bus Station to Zhao County, get off at the terminal station. Get off the bus and go west, take the Zhaoxian No. 2 bus at the stop sign at the traffic light on the west side of the Berlin Zen Temple, and the terminal is the Zhaozhou Bridge Scenic Area.

In addition: there are three-wheeled and taxis to Zhaozhou Bridge at the entrance of Berlin Zen Temple, but the buses in Zhao County are more convenient, the departure interval is small, and the ** is cheap, so it is recommended to take the bus to go.

The Yongji Bridge in Zhuozhou, Hebei Province is the longest stone arch bridge in ancient China.

The Yongji Bridge has a total length of 627 65 meters, including the approach bridge. This bridge is located on the Juma River in the north of Zhuozhou City, and is a nine-hole stone bridge. According to the records of Zhuozhou County, Yongji Bridge was built in 1574 and was implied to be rebuilt after many discussions.

In 1760, due to the southward movement of the river, a new bridge was built in the south of the old bridge, and the body of the Hanxiao bridge was all made of rectangular boulders, and the north-south approach bridge was built, and there were 22 culverts under it.

First of all, the arch rib is a compression member, the ancient materials are mainly wood and stone (I will mainly discuss the stone arch bridge here, the wooden arch bridge is stopped), stone is a good masonry material, similar to the current concrete, by the compression member to choose a good masonry material, which explains the ancients in the selection of materials this link.

Then, on the issue of the arc of the arch axis mentioned, I also want to explain first, the choice of the arch axis, in the present is mainly composed of, arc line, secondary parabola, higher order curve, catenary line, etc., here is a key problem, the question mentioned, why the axis of the ancient arch rib is relatively large, because the arc is large, the arch effect of the arch rib, that is, the characteristics of compression, if the arch rib is too flat, then the effect of the beam is greatly reflected, and the effect of the bending moment is greatly increased, Bending moment we know, will let the arch rib section press down and pull, the soft rib of the masonry material is reflected, the tension is absolutely unfavorable, in the present, steel is a good tensile compression member, even if it is modern concrete, the tension is also very difficult, so this explains why the ancients chose a relatively large arc arch axis, that is, for safety reasons, of course, the larger the radian, the more beautiful the curve can be reflected.

1. Arch ring masonry.

1) Arch ring lofting.

The arch stone of the stone arch bridge should be processed according to the design size of the arch ring, and in order to ensure that the processing size is correct, it is necessary to make the arch stone model.

Small span arc and other cross-sectional arch rings, because of the simple cross-section, can be calculated to determine the size of the arch stone, with wooden boards to make a model, generally do not need to release the main loss of the circle sample. However, the large and medium-span catenary arch ring needs to release the arch ring according to the ratio of 1:1 on the sample table to determine the shape and size of the arch block and the segmented position of the arch ring.

The sample table can be selected in a relatively flat and spacious place near the bridge position. When the two halves of the arch ring and the arch are symmetrical, only half of the hole can be released, and when the two half holes are asymmetrical, the whole hole needs to be released.

2) The sequence and method of masonry main arch ring.

When building the arch ring, the masonry sequence of the arch ring should be designed according to the span, sagittal height, thickness and arch situation of the arch ring. The masonry order of the arch ring is as follows:

When the arch circle with a span of 10m is built with a full arch frame, it can be symmetrically built from the arch feet at both ends in order, and finally the arch capstone.

When the span diameter is 10m and the arch frame masonry arch ring and the arch ring with span diameter is 13 20m, can adopt segmented symmetrical masonry; Each half span should be divided into three sections, symmetrically masonry from both ends of the arch foot, and finally the capstone is closed.

3) The arch circle is closed.

With the different spans and design requirements, the arch ring closure method is divided into three types: the installation of the vault capstone, the capping and closing of the brake tip and the capping and closing of the pre-applied pressure.

2. Masonry of arch structures.

1) Masonry time.

When the arch structure is masonry before the arch frame is unloaded, it should be carried out after the mortar strength of the arch ring closes reaches the design mark of more than 30. When the structure of the arch is built after the loose frame, it should be carried out after the mortar strength of the arch ring is closed to reach the mark of more than 70. The arch ring built by the ring should be carried out after the strength of the mortar to be sealed reaches the design mark of 70 or more.

2) Masonry method.

The masonry of the arch structure should be carried out in accordance with the principle of symmetry and balance.

The solid belly arch structure should be symmetrically stepped masonry from the arch foot to the vault. Soffit filler can be filled with the order of side wall masonry. When the amount of filler is large, it can also be filled in the side wall after the masonry.

Because there is no specific architectural design record of how to build arch bridges in ancient times, we have to speculate on the construction of arch bridges in ancient times according to the actual level of science and technology and productivity in ancient times.

(1) The structural form and stress characteristics of the arch bridge.

Under the action of vertical load, under the condition of reasonable arch axis, the arch as a stressed member, the axial force and bending moment of the main bearing should be avoided as much as possible, so as to give full play to the characteristics of the arch rib section as an axial stressed member, and efficiently use the component section. Since we know that the arch is an axially stressed member, at the end of the arch, i.e. at the foot of the arch, x and y forces are generated. Therefore, the key stress problem to be solved by the arch bridge is the strength of the arch rib itself and the arch foot foundation under the action of horizontal and vertical forces, and the arch bridge is more reflected in the horizontal force, that is, the arch bridge should ultimately be a thrust structure.

(2) The structure and architectural ideas of ancient Chinese arch bridges.

Ancient Chinese arch bridges are more up-bearing arch bridges, that is, the bridge deck system and transmission structure are above the arch circle, that is, the so-called building upper arch, that is, the so-called up-bearing type. The bridge deck bears the load directly and then transfers to the underside of the arch ring and finally to the arch foot.

First of all, the arch rib is a kind of compression member, the ancient materials are mainly wood and stone (I will mainly discuss the stone arch bridge, the wooden arch bridge counts), stone is a good masonry material, similar to the current concrete, by the compression member to choose a good masonry material, which shows that the ancients in the selection of this link.

Then, on the issue of the arc of the arch axis, I would also like to explain that the choice of the arch axis is mainly based on arcs, quadratic parabolas, higher-order curves, catenary lines, etc. There is a key question, which mentions why the axis of the arch rib in ancient times was larger, because the radian, the rib effect, that is, the characteristics of compression can be reflected.

Finally, there is the choice of the basics. As we all know, the foundation of Zhaozhou Bridge is very good, and the problem involved here is not the so-called one-sided arch bridge, the so-called barge scouring, foundation settlement, the control of Zhaozhou Bridge is very good, and the foundation is extremely critical as the lifeline of the arch bridge.

Zhaozhou Bridge, also known as Anji Bridge, is located on the Huhe River in Zhaoxian County, Hebei Province, across the north and south banks of the Huanshui River, because the bridge body is all built with stones, commonly known as "Big Stone Bridge". Built in 595-605 A.D. during the Sui Dynasty, designed and built by the famous craftsman Li Chun, it has a history of about 1500 years, and is the earliest and most complete ancient open-shouldered stone arch bridge in the world today. In the long years, although it has been hit by countless floods, wind and rain, erosion of ice, snow and frost and 8 times, it is safe and sound, standing majestically on the Qingshui River.

Zhaozhou Bridge, the length of the bridge is 50 82 meters, the width is 9 60 meters, the net span of the large arch is meters long, and the arch is high. The characteristics of the bridge are:

1. The whole bridge has only one large arch, which is meters long, which can be regarded as the longest stone arch in the world at that time. The bridge hole is not an ordinary semicircle, but resembles a bow, so that the road above the arch has no steep slope, which is convenient for cars to get up and down.

2. On the shoulders of the large arch, there are two small arches each. This is a creative design, which not only saves stone and reduces the weight of the bridge, but also increases the amount of water passing through the bridge tunnel when the river rises, and reduces the impact of floods on the bridge. At the same time, the arch is added to the arch, and the bridge body is also more beautiful.

3. The arch is made up of 28 arch circles, just like so many bows of the same shape are combined together to form an arc-shaped bridge hole. Each arch ring can independently support the weight above, and if one is broken, the others will not be affected.

Fourth, the structure of the whole bridge is symmetrical, and the surrounding scenery is very harmonious; The stone railings on the bridge are also carved in a quaint and beautiful way. Zhang Ling of the Tang Dynasty said that looking at this bridge from a distance is like "the first moon rises out of the clouds, and the rainbow leads the stream". The high technical level and immortal artistic value of Zhaozhou Bridge fully demonstrate the wisdom and strength of China's working people.

The design concept and craftsmanship of Zhaozhou Bridge are not only second to none in China's ancient bridges, according to the research of the world's bridges, such open-shouldered arch bridges only appeared in Europe until the middle of the 19th century, more than 1,200 years later than China.