Pre-pressing construction method of assembly type 0 # block construction bracket

Abstract

The invention discloses a pre-pressing construction method for a fabricated 0 # block construction bracket, and belongs to the technical field of bridges. The method comprises the following steps: mounting the 0 # block construction bracket, pre-pressing by using a pre-pressing assembly in a graded tension loading manner, and removing the 0 # block construction bracket. When the pre-pressing load piece is tensioned and loaded, the tensioning ends of the steel strands bear tensioning stress which is tensioned inwards along the top wall, the tensioning stress acts on the upper longitudinal beam assembly through pulley limiting and direction changing, the anchoring ends of the steel strands are tensioned downwards, and pre-pressing load is achieved. The steel strands are converted in the horizontal and vertical directions. The length of the steel strands is the stroke of the upper longitudinal beam assembly bent to the top wall of the bridge pier body through the lower counter-force beam assembly, is only related to the length of the upper longitudinal beam assembly, the distance between the upper longitudinal beam assembly and the lower counter-force beam assembly, the length of the lower counter-force beam assembly, the distance between the lower counter-force beam assembly and the top wall of the bridge pier body and the like, and is not related to the height of the bridge pier body, and the stress loss of the steel strands is effectively reduced.

Description

technical field [0001] The invention relates to the technical field of bridges, in particular to a preloading construction method of an assembled 0# block construction bracket. Background technique [0002] The superstructure of continuous girder bridges often adopts the construction method of pouring or installing in sections and finally closing them. Block 0# is the reference block for the first construction of the superstructure of the continuous girder bridge, which is usually cast in-situ directly on the top of the bridge pier by using the "bracket method". The 0# construction brackets used in the existing technology are all steel structure components, and its components are usually processed and manufactured at the construction site or in the factory, and finally installed uniformly at the construction site. According to the requirements of relevant specifications, after the installation of the construction bracket is completed, before the official construction of blo...

AI Technical Summary

Problems solved by technology

[0006] Loading preloading generally requires the preparation of preloading materials (sandbags, concrete prefabricated blocks, water tanks, etc.) in advance, which requires a longer preparation period and a larger stacking site

In addition, all kinds of materials used for pre-pressing are disposable consumables, which will be discarded after pre-pressing, resulting in a huge waste of materials and increased construction costs

[0007] (2) There are many hoisting times and great safety risks

After the preloading is finished, the hoisting equipment is used again to hoist the preloaded materials from the top of the bracket to the ground at the bottom of the pier for unloading. The number of hoistings in the process is extremely large. The impact cannot be ignored. On the other hand, repeated reciprocating hoisting will greatly increase the safety risk in the construction process, especially in the case of high pier, the safety risk will increase exponentially

[0009] (3) The process is easily affected by the environment and climate, resulting in data distortion

It can be seen that the workers staying on the top of the bracket are always in an unsafe working environment

In addition, in the existing process, jacks are used for loading. This loading method is difficult to be integrated and synchronized, and it is easy to cause the bracket to be twisted and deformed, further increasing the safety risk in the process.

[0014] (2) Stress loss is prone to occur, resulting in data distortion

[0016] (3) The appearance quality of concrete is affected

[0017] Before preloading, it is necessary to embed more counterforce devices or their parts with large structural dimensions in some positions of the bridge pier body or on the cap under the pier. After the preloading is completed, use the grinding wheel cutting process or the oxygen cutting process Removing the reaction device will leave a "scar" on the concrete surface of the bridge structure that is difficult to modify, seriously affecting the appearance quality of the concrete

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