Construction method of deformable template of variable cross-section high pier

Abstract

The invention discloses a construction method of a deformable template of a variable cross-section high pier, which comprises the step of installation of each pouring section external mould assembly, wherein each pouring section external mould comprises a plurality of layers of templates which are fixedly superposed together in sequence from bottom to up; each layer of template is formed by the encircling of two transverse templates and two longitudinal templates; the transverse templates are rectangular and have the width equal to that of a pier; the longitudinal templates are isosceles trapezoid and have the altitude equal to that of the transverse templates; and the next step of operation can be conducted according to the existing method after the installation of each pouring section external mould assembly is completed. With the method, a tower crane and a large template are omitted, the cost is saved, the defect that a large device is difficult to transport in an access road in mountain area is overcome, the construction is convenient, the period is shortened, and the construction quality is improved.

Description

Technical field [0001] The invention relates to a construction method of bridge piers, in particular to a construction method of variable formwork for high bridge piers with variable cross-sections, and belongs to the technical field of bridge construction. Background technique [0002] Variable cross-section high bridge piers are the most common form of substructure in mountain highways and general highway bridges, especially when the bridge structure is relatively high. Generally, there are two types of variable cross-section hollow thin-walled piers and variable cross-section solid high piers. The change of its cross-section is usually the horizontal width is constant, and the vertical dimension gradually decreases from bottom to top. [0003] In the actual construction of mountain roads, there are generally two common construction methods for variable cross-section high bridge piers: 1. Tower crane and large formwork hoisting construction; 2. Steel pipe scaffolding platform com...

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Problems solved by technology

[0004] The first scheme has the advantages of short construction period and low construction difficulty, but the construction cost is relatively high (≥600 yuan / m 3 ), high requirements for hoisting equipment

Tower cranes and large formwork are usually used for hoisting construction, but in mountainous areas, bridges are designed to cross heavy hills and valleys, and bridge piers are located in high mountains and ravines. The hillsides have large transverse slopes and many landslides. It is difficult to open access roads and connected roadbeds. It is bad, and it is difficult for large-scale equipment to enter the site; at the same time, there are quite a few bridges with relatively few piers, and the rent and access fees for large-scale formwork, machinery and tools will greatly increase the construction cost of the unit project

All these reasons limit the use of traditional large formwork tools

[0005] Although the construction cost of the second option is relatively low, the requirements for hoisting equipment are not high, and the formwork can be reused, the construction period is long and the construction is difficult. The biggest problem is the poor appearance quality of the pier column

[0007] First, the section deformation makes the steel formwork unsuitable for general use. Generally, one side of the pier section is sloped at a small ratio of 1:80 or 1:100 according to the height. It is difficult to control precisely, and the slight deviation will bring about the accumulation of errors (the pier column is as high as 40m~90m), which will affect the overall appearance of the pier column

[0008] Second, if the tower crane cannot enter the site, the formwork can only use the traditional combined steel formwork, but the overall rigidity of the combined formwork itself is poor

Commonly used combined steel mold area is 0.2~0.5 m 2 , seams and misalignment are serious, and the stiffness after combination is poor, which cannot meet the construction technical requirements of the "Assessment Standards"

[0009] In order to solve the above problems in some bridge projects, the formwork is designed as a standard parallelogram large steel mold to meet the needs of slope changes and large areas. At the same time, some trapezoidal and triangular steel molds are made to complement the middle part of the two quadrilaterals. However, there are three problems in this scheme: 1. The trapezoidal and triangular formwork in the middle has a large amount of production and low utilization rate. It needs to be made from the bottom of the pier to the top of the pier. It can only be used once in the construction of each pier; 2. Due to the low utilization rate of trapezoidal and triangular formwork, the appearance and color of the completed bridge pier are often inconsistent, and the post-processing is difficult; 3. The size of such formwork is not much different and the shape is similar. It is easy to be confused and difficult to manage, and some small parts will affect the construction of the entire bridge pier if it is lost

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