How were the piers of the sea crossing bridge built in such deep water?

This question has been said, the cross-sea bridge.

Generally, the place where it was built was an inland sea.

The depth is generally within a depth of several tens of meters, although there is a difficulty in construction, but it does not mean that there is no way to build, of course, for the construction of places with a depth of more than 100 meters, basically will not use the cross-sea bridge to build, but will use the submarine immersed tunnel to build, so the sea bridge is a shallow sea area building.

So how to build the piers of the sea bridge, in fact, there are several methods, each method will be selected according to different sea conditions, the first is the steel box structure, which is in the hydrological conditions are complex, and the island cofferdam cannot be used.

and steel sheet piles.

In the case of a deep-water construction method, there are often single walls and double walls.

There are two kinds, the single-walled one is suitable for shallow water positions, and the double-walled ones are compressively resistant and suitable for deep water areas.

This is a bottomless structure, the bottom is directly inserted into the seabed after sinking, this can choose various shapes, square and round can be, when sinking to the bottom of the sea, layer by layer assembly, using the sealing structure combination module assembly, after assembling higher than the sea surface, the use of underwater concrete.

Back to the bottom, and then drain the water inside, so that a steel cofferdam is formed, and the construction of bridge piers can be carried out in it, this kind of steel sleeve box, the internal structure is provided with a lot of impassable water tanks between the inner and outer two layers, which is convenient for sinking and drainage.

There is also a similar is to drive the pile first and then build the weir, that is, first set up the drilling platform at sea, carry out the construction of the drilling village, and then the steel casing box is assembled and launched with the help of the drilling platform, the use of the water trap inside the steel casing box to float and the lifting ring to let it float on the water surface, the second section of the steel casing box is spliced on the water surface, the use of slow water injection to make it sink, in the third section of splicing, until it completely sinks to the bottom of the sea to form a cofferdam, the advantage of piling first is that the positioning is accurate and will not be affected by the water flow, and then empty the water after doing business.

There is also a method of steel casing, which is also to erect a drilling platform to pile to build a stable platform, and then use the method of caisson to surround it, use a large giant steel casing to sink into the water, drive into the seabed, and then empty the water in the steel pipe to operate in the steel pipe, this method is suitable for low load-bearing conditions, hydrological and sea conditions and geological requirements are also relatively special, but the utilization rate is still very high.

A method that is less used in the shallow sea area is through the construction of the cofferdam, which is used less, the use of steel casing box is the most common, and the method of direct piling immersed pipe is used in shallow water area, such as some river outlets, etc., that is, the piling platform is directly erected for piling, not using steel casing, but using a large steel casing cement pipe to directly sink to the bottom for pier construction, which is used in the shallow water area where the hydrology is stable.

Under normal circumstances, this kind of bridge is built in the inland sea, and the depth of the inland sea is not particularly deep, about a few tens of meters, so it can be built completely.

It took a lot of manpower, financial resources, and material resources to build, and it was not easy, and at the same time, high-tech technology was adopted.

It was built using an undersea tunnel, and in building such a bridge, human beings used their own wisdom and tools.

First, the sea-crossing bridge was built on the inland seaTarget. First of all, the piers are operated by professional tools and are not built in deep seas. Most of the piers were built at the mouth of the river, and engineers did not choose to build them at a depth of several hundred meters or kilometers.

The engineer formulated according to local conditions and adopted a suitable construction plan for the smooth construction of the bridge. The most important thing is to look at the condition of the seabed underwater. For the construction of bridge piles, the quality of the soil on the seabed should also be checked.

The anti-corrosion standard of high-speed rail engineering structure is 100-year anti-corrosion, and the main anti-corrosion method for steel structure is to choose durable heavy anti-corrosion coating.

The second is to rely on their own experience and advanced technology to determine the location of the bridge pier. It is not easy to lay the foundation of a bridge pier in the water, so it is necessary to put a steel ring in the water, then drive the steel ring into the seabed, and weld the second ring to the first ring until it becomes a large circle pipe. What should be considered is the accumulation of sediment on the piers.

The more docks, the more sediment that can block the passage of the waterway. First of all, it is necessary to consider the passage of waterways.

The second is the concrete composite beam, which is composed of a concrete bridge deck and a channel-shaped steel beam. The steel girder is lightweight, which is suitable for the construction of long-span bridges, while the concrete bridge deck improves the stiffness of the bridge. The combination of the two meets the requirements for the passage of high-speed trains.

On long-span sea-crossing bridges, the laying of ballastless tracks and the passage of high-speed trains have extremely high requirements for the structural stiffness, creep deformation and dynamic performance of the bridge. After several simulation tests, the design team found the structural parameters of the steel-concrete composite beam suitable for the long-span marine environment.

In addition, the steel is corrosion-resistant with nickel and streamlined box-shaped wind resistance. Compared with ordinary bridges, cross-sea bridges also face another test, that is, sea breeze and seawater corrosion, which is a common problem faced by marine engineering construction in all countries in the world. In humid air, the water film formed on the surface of the steel will dissolve carbon dioxide, sulfur dioxide, hydrogen sulfide and other gases in the atmosphere, so that the water film contains a certain amount of hydrogen ions to form a film containing electrolyte.

This is exactly the same as in steel. Iron and a small amount of carbon make up the galvanic cell.

Under each pier there is a cap, and in the shallow water near the shore, the cap is constructed using the cofferdam method.

There are two ways of cofferdam method, the first is to use steel sheet piles, and the other is to use earth-rock dams, where the water is blocked in shallow seawater, and the position where the bridge piers are to be built, and then the water and sediment in the enclosed area are drained by a pumping machine until the ground is exposed.

This creates a cofferdam in the middle, in which workers can work, similar to work on land. When the work is completed, the steel plate outside the cofferdam is removed. This method is suitable for construction in shallow water, and the difficulty is relatively low, but it requires a large amount of space, which is time-consuming and labor-intensive, and has a certain impact on the surrounding water environment and marine life.

The bridge is built using large-scale medical equipment combined with artificial and high-tech construction methods, and generally needs to be graded first, and gradually begin to rise after the foundation is built on the seabed. Most of the bridges were shot with instruments weighing hundreds of tons.

All the structures of the bridge will be built first, and then assembled by installation. The piers are secured by instruments and then locked below sea level.

The sea is so deep that the piers of the sea-crossing bridge are made by professional machines. and equipment to pour the concrete on the seabed. Therefore, despite the depth of the sea, the bridge hole is still very strong. This is also the advancement of science and technology.

The sea is so deep, and the piers of the cross-sea bridge are so "buried" into the ......Usually the cast-in-place pile is used, the construction is carried out with special machinery, and the bridge pier is constructed after the pile foundation construction is completed, which involves the methods and measures of civil engineering construction in the water.

The first is called the pile foundation method, in which the pile-driving ship drives the steel piles into the corresponding position, and these steel piles need to be long enough to pass through the sediment and drive all the way to a sufficiently solid soil layer. The soil layer on which the pile bottom is located serves as the foundation, and finally a cap is built between the pier and the pile. The second is pile sinking, which is equivalent to a section of columns hammered into the sea by a pile driver, the material of these columns will vary according to the water flow environment, generally steel, prestressed reinforced concrete and other corrosion-resistant materials.

Similarly, the pile is pulled to the designated position by boat, and then driven into the seabed by the offshore pile driver section by section, and the pile foundation needs to be made as a cushion cap, and the deep-water cushion cap will use the bottom sleeve box cofferdam, and the shallow water cushion cap is a steel sheet pile cofferdam to isolate the water. This was done by installing the piers, which were mostly prefabricated in advance and transported by boat.

How the "sea base" of the sea-crossing bridge was built. There are three ways to do this.

The first method: the cofferdam method.

The construction of piers on the seabed is a huge undertaking but can be less maneuverable on land, and the cofferdam method came from this inspiration.

This method is mainly applicable to the shallow sea area, simply put, in the shallow sea water area, with cement steel plates and other put into the sea to form a circle, the height of this circle is equal to the height of the seabed to the sea surface, and then use a pump to drain the water inside, so that the circle becomes a deeper land.

Since it has become land, it is much easier to operate, according to the method of building high-rise buildings on the ground, lay the foundation to build the bridge piers, and after the bridge piers are completed, then remove the circle on the side and wait for the surrounding sea water to recover.

The second method: the caisson method.

The specific operation of this method is to put a huge cylinder with a hollow bottom and no cap into the seabed, and then fill the huge cylinder with cement, so that when the cement slowly solidifies, the weight of the huge cylinder will gradually increase because of the cement, and then sink into the soil of the seabed, until it falls to the target depth estimated by the construction personnel and then stop pouring cement, and then seal the top of this huge cylinder, so that the "sea base" of the bridge pier in the deep sea area is completed.

The third method: piling method.

Modern times in the construction of sea-crossing bridges will plan the route in advance, try to avoid encountering extremely deep sea areas, if you can't avoid it, then you can only use the third method, piling method.

This method can be said to be an advanced method of the caisson method, which is to put in a hollow column in advance and pour cement into it, and use the weight to drive it into the seabed. The piling method is to load the solid piles of the "sea foundation" on the ship in advance, and use the pile driving ship to put the solid piles into the seabed to create a "sea foundation".

These are the three ways to build piers, but building a bridge across the sea is not only about how to build the piers, but also about other issues, such as the anti-corrosion effect and anti-collision ability of the piers.

The sea is so deep, how did the piers of the sea-crossing bridge "buried" into it? This is the technology of science and technology, the first is the caisson method, which is to sink a hollow cylinder into the water, and then close the bottom layer, and then use the machine to pump the water in the barrel, and then pump the water to the almost, and then put in the concrete to let it solidify, my country's Yangtze River Bridge is caused by this method. Another method is to sink the pile, first of all, you need to sink a section of the pillar into the seabed with a pile driver, this is a very test of the master's technology, a careless will be in vain, because the material of the column will change according to the water flow environment, so it needs to be surveyed for a long time before construction, this kind of project dealing with water, the process of building the bridge is quite difficult, and now we see the cross-sea bridge, which is how it was built.

The sea is so deep, how did the piers of the sea-crossing bridge "buried" into it? In fact, the piers of the cross-sea bridge are not buried, but drilled to a certain depth on the seabed with a drilling rig, which is the depth that meets the safety requirements of the bridge design, and then the piers are buried in, and the piers are poured with high cement concrete and steel bars, and the piers can penetrate into the submarine rock layer. to complete the construction of the bridge piers.

The sea is so deep, how did the piers of the sea-crossing bridge "buried" into it? The first is the caisson method, which is to sink a hollow cylinder into the water, then close the bottom layer, and then use the machine to pump the water in the barrel, and then the water is almost pumped, and then put in the concrete to let it solidify, and the Yangtze River Bridge in my country is caused by this method. Another method is to sink the pile, first of all, you need to sink a section of the pillar into the seabed with a pile driver, this is a very test of the master's technology, a careless will be in vain, because the material of the column will change according to the water flow environment, so it needs to be surveyed for a long time before construction, this kind of project dealing with water, the process of building the bridge is quite difficult, and now we see the cross-sea bridge, which is how it was built.

It's not buried. This involves the methods and measures of underwater civil engineering construction. Sea-crossing bridges are usually constructed with cast-in-place piles and special machinery. After the pile foundation construction is completed, the bridge pier will be constructed.

Located in the deep sea, this cross-sea bridge has a high-tech content for the installation of piers. First of all, the underwater pier is mainly composed of invisible pile foundations, bearing caps and piers and supports on the sea surface, and in order to build a good pier, the pile foundation must be laid first. Generally, there are two types of underwater pier pile foundations.

One is caisson foundation. In layman's terms, it is equivalent to putting a cylinder on the surface of the water, and then using a boat to pull it to the designated position, and then deduct it into the barrel to pour concrete, let the barrel sink, and then put concrete on top of the barrel, and let them pass their own weight until the bottom, and the second is the pile sinking pile, which is hammered into the sea by the pile driver, the material of these pillars will be different according to the water flow, environment, etc., generally steel. Corrosion-resistant materials such as prestressed reinforced concrete, the pile is also pulled to the designated position by boat, and then driven into the seabed by the offshore pile driver section by section, and the pile foundation needs to be made as a cushion cap.