Pre-tensioning track slab pre-tensioning jack and its method of tensioning track slab prestressed threaded steel bar

Abstract

The invention belongs to a device and a method for tensioning a track board and in particular relates to a pre-tensioning jack for a pre-tensioned track board and a method for tensioning a pre-stressed twisted steel of a track board by use of the pre-tensioning jack. The pre-tensioning jack comprises a piston and an inner cylinder which are arranged in a cylinder sleeve and in nesting fit with each other, wherein the cylinder sleeve is connected with an oil pump by use of a pipeline; the pre-tensioning jack further comprises a fixed nut rotating mechanism composed of a box, a first hydraulic motor, a pinion, an inside hexagon sleeve gear, a pre-stressed tendon locking mechanism composed of a second hydraulic motor, a supporting seat, a threaded pull rod and the like. The pre-tensioning of the pre-stressed twisted steel is realized by virtue of the steps of connection preparation, connection in place, tensioning in place, anchoring in place, back jacking in place, connection completion and the like. The pre-tensioning jack for the pre-tensioned track board and the method for tensioning the pre-stressed twisted steel are used for solving the problems of poor accuracy, high labor intensity and the like of the prior art, and have the advantages of great improvement of construction quality and working efficiency, high construction accuracy and the like.

Description

technical field [0001] The invention belongs to track slab stretching equipment and methods, in particular to a pre-tensioning track slab pre-tensioning jack and a method for stretching track slab prestressed threaded steel bars by using the same. Background technique [0002] In the field of track slab prestressing construction, the track slab tension generally adopts the pretensioning method, that is, the prestressed threaded steel bars are stretched first, and then the concrete is poured after the stretching is completed. Tensioning needs to be completed in two steps, pre-tensioning and final tensioning. Pre-stretch one end of the pre-stressed threaded steel bar one by one, stretch it to the specified value according to the construction drawings or technical specifications, until the pre-stressed tendons on each track slab are pre-tensioned. The final tension is carried out at the other end, and the final tension adopts the overall tension. The overall tension means that...

AI Technical Summary

Problems solved by technology

[0003] In the current construction method, manual wrench, impact wrench, simply screwing the fixing nut or self-made simple tooling are generally used to lock the nut at the pre-tensioning end. Only by manually sensing whether the pre-tensioning is in place, the accurate value of the pre-tensioning cannot be guaranteed. Some also use a torque wrench for pre-tensioning, and the tension is determined only by the consistency of each torque value

The final stretching adopts overall stretching, and if the pre-stretching is not accurate, the data of the final stretching will be inconsistent. The final stretching will be stretched according to the pre-stretching that is not in place, and those that are in place will be over-tensioned; if the pre-stretching is in place If tensioning is carried out, the final tension will lead to the same result due to insufficient pre-tensioning or over-tensioning, resulting in early fatigue of prestressed tendons and endangering the service life of the track slab

The steel bars with large effective prestress bear the force that should be borne by all the prestress bars, so the steel bars with large effective prestress gradually yield during the use stage, resulting in insufficient or excessive prestress of the prestress bars inside the track slab, resulting in The internal prestress of the track slab is uneven, and the vibration of the train on the upper track slab will transmit the vibration force to the track slab, which accelerates the uneven internal force of the track slab and greatly reduces the life of the track slab

It has buried potential safety hazards for the track slab in the future use process, and even accidents such as train overturning may occur

[0004] Although the nut can be tightened with an impact wrench, there are the following problems: First, the impact on the human body is relatively strong, and the human body is often impacted, and the operator will feel uncomfortable when operating, resulting in unnecessary casualties.

The second is that the operator needs to carry the wrench to work. Due to the high quality of the wrench, the labor intensity is high and the efficiency is low.

The third is that it cannot reflect the tension data, and can only be operated by feeling

[0005] A torque wrench is a bolt fastening tool that can output and set torque. The value of tension is converted from the torque value, which is greatly affected by the friction force, the unevenness of the nut surface, and the heat treatment hardness of the nut surface. The tension is not a fixed value, the value is too small, and the error between the values ​​is very large, which seriously exceeds the precision requirements of the tension

[0006] The method of manual construction with a manual wrench is complicated in operation procedures, affected by human factors, the prestressed tension value is generally insufficient, and there are problems such as high misoperation rate, high construction intensity of personnel, and low construction efficiency.

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