What Is a Cantilever Bridge?

Each section of the cantilever bridge is supported in the middle, not at both ends. The bridge's identity is long and sturdy, similar to a truss bridge. Each section is supported by the same structure in the river, making it balanced. Where the sections meet, there is a short span. According to the manufacturing method of the bridge beam body, the cantilever construction technology can be divided into two categories: cantilever pouring technology and cantilever assembly technology. The cantilever pouring process is the use of a suspended movable scaffold (referred to as a hanging basket) to symmetrically and uniformly pour concrete beams of 3 to 8 meters on both sides of the bridge pier during construction. After the completion of the pouring, the concrete must reach the required strength. Tension the longitudinally prestressed steel strand, and then move the hanging basket forward for the next stage of construction.

According to the manufacturing method of the bridge beam body, the cantilever construction technology can be divided into two categories: cantilever pouring technology and cantilever assembly technology. The cantilever pouring process is the use of a suspended movable scaffold (referred to as a hanging basket) to symmetrically and uniformly pour concrete beams of 3 to 8 meters on both sides of the bridge pier during construction. After the completion of the pouring, the concrete must reach the required strength. Tension the longitudinally prestressed steel strand, and then move the hanging basket forward for the next stage of construction. The bridge box girder cantilever pouring is roughly divided into four parts. The first part is the 0 and 1 blocks for construction, the second part is the cantilever section of the 2 to 8 blocks for the cantilever pouring, and the third part is the side span casting. The fourth part of the construction of the section is the construction of the closing section, which can also be subdivided into the construction of the side-span closing section and the construction of the middle-span closing section. The cantilever bridge construction technology is not affected by the terrain during the construction, and is suitable for the construction of bridges with complicated terrain and large spans. The cantilever bridge technology is not limited to the construction of cantilever bridges, but is more widely used in the construction of concrete bridges with large continuous spans. There are also certain shortcomings in the cantilever construction process. For example, the construction period of the bridge is relatively long, and the construction technical ability needs to be improved. The calculation and analysis before construction and the strengthening of construction technology training need to be improved and improved. ^[1]

(1) Hanging basket design and construction: In bridge construction, the cantilever hanging basket technology has been relatively mature. The hanging basket is a movable operating platform that can walk along the track, and is an important component of the cantilevered box girder. On the front-end box girder section of the construction, during cantilever pouring, the grouting, formwork installation, pipe installation, steel reinforcement, concrete pouring, section tensioning and grouting of the box girder section are carried out on the hanging basket. When a beam segment

(1) Advantages and disadvantages of cantilever construction technology: The cantilever bridge construction technology was invented in the late 1950s. The reason why it is still widely used in bridge construction is inseparable from its unique advantages and advantages in its own application.

(2) The space under the bridge under the cantilever bridge construction process is relatively wide, which has obvious advantages over construction methods such as full-frame supports.

(3) With the development of science and technology, the emerging bridge dyeing is diverse, and the cantilever bridge construction process is applicable to many types of bridge construction, such as steel frame bridges, cable-stayed bridges, arch bridges, and so on.

(4) The cantilever bridge has a simple construction process, less construction equipment, and a higher degree of mechanization, which can save manpower, material and financial resources.

(5) Because the cantilevered bridge is formed at one time, it can reduce part of the construction procedures, simplify the bridge construction procedures, and improve work efficiency.

(6) Due to the high degree of mechanization of cantilevered bridges, it is easier to achieve connection and closure, and the overall engineering quality of the bridge has been greatly improved.

(7) The terrain is uneven during the construction of the bridge. Some bridges have large spans, while others need to cross rivers and gullies. Such construction terrain is not suitable for all construction methods, and the construction technology of cantilever bridge is affected by the construction terrain. Smaller, it is also more suitable for long-span bridge construction. Each construction method cannot be perfect, and so is the construction technology of a cantilever bridge. Although it has the above advantages, it also has some disadvantages that need our attention. For example, the construction monitoring of a cantilever bridge is more complicated than other methods. All bridge pier surfaces can only be cantilevered after construction. The construction period is relatively fixed. The construction time is longer than other construction methods. There are also some construction errors, and the block contact surface will inevitably have unevenness.

(1) Box girder concrete pouring shall be completed once, and no second pouring shall be taken. In addition, no matter what level of pouring, no bleeding can occur.

(2) When the support of the side span closing section is extended, it should be unloaded while pouring concrete. 50% ballast lock of the cantilever end closing section weight should be guaranteed.

(3) Because the cantilever pouring basket construction is an important process in the bridge construction process, corresponding safety plans should be established at the same time when the construction organization design plan is formulated, such as anti-fall baskets, anti-tensioning anomalies, and natural environment anomalies, and Relevant accident rescue plans.

(4) The last process of overhanging box girder is closing. The control goal during hanging pouring is to select the height difference at the low temperature when measuring the height difference at both ends.

(5) The hanging basket is the main equipment in the cantilever pouring process. Before the concrete is poured, the stress condition of the hanging basket boom, the rear anchor point and other equipment should be carefully checked in order to find the problem and solve it in time.

With China's increased investment in public facilities and the rapid development of the bridge industry, construction technology and construction methods have been greatly improved. In recent years, with the aid of computers and other auxiliary facilities for analysis and calculation of bridge construction and construction control, the technology of cantilever bridges must also be better developed and improved. Cantilever bridge construction technology will also inevitably become an important construction method for modern long-span bridges. It will definitely play an increasingly important role in bridge construction. This technology should be applied well to promote faster and stronger development of the bridge industry ^[3] .