Simplified prestress test method for obtaining test parameters in engineering structure

Abstract

The invention discloses a simplified pre-stress test method for acquiring test parameters in an engineering structure, which comprises the following steps of: firstly, selecting a pre-stress pipeline of a typical beam slab according to an engineering scale, and collecting the arrangement of pre-stress steel bundles and pipeline parameters of the pre-stress pipeline; then, a tensioning device is built, double-end grading tensioning is conducted on the prestressed steel beam, tensioning force at the two ends of the steel beam and the elongation of the prestressed steel beam are read and recorded, an equation is built to assume the center point of the steel beam, and calculation is conducted according to an algorithm; and final tensioning is completed according to the predicted value. The double-end tensioning algorithm replaces a traditional friction resistance experiment single-end tensioning method, so that a double-end tensioning friction resistance experiment is achieved; single-end tensioning is changed into double-end tensioning, the problems of pipeline bending and uneven stress of prestressed tendons during single-end tensioning are solved, the use efficiency of the prestressed tendons is improved, and the prestressed tendons are more in line with actual engineering conditions.

Description

technical field [0001] The invention belongs to the field of bridge engineering, and relates to a double-end stretching method of prestressed prestressed steel tendons, in particular to a simplified prestressed test method for obtaining test parameters in engineering structures. According to the characteristic that the prestressed prestressed steel tendons in bridge engineering are mostly symmetrically arranged before tensioning, the single-end tensioning of the traditional friction test is improved to double-end tensioning through the algorithm, and the offset of the tensioning center point, The correction calculation of friction loss and tensile prestress is used in post-tensioning construction, making the test more convenient and fast, and increasing the accuracy of prestress application. Background technique [0002] At present, in order to ensure the accurate application of beam prestress, in addition to strictly controlling the positioning and hole-forming process of t...

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Problems solved by technology

[0003] 1. When using the friction test of the single-end tension method, it is necessary to determine the number of series jacks used at the tension end according to the sum of the elongation calculations on the design drawing, because the elongation of the entire tension beam during single-end tension They are all concentrated at the tensioning end, and the cylinder stroke of a single tensioning jack is limited. In addition, a friction test requires multiple prestressed tendons to participate in tensioning, and each prestressed tendon needs to be stretched twice at a single end. The efficiency low;

[0004] 2. The prestressed steel tendon with single-end tensioning method has a large prestress loss after tension, and the effective prestress obtained at the fixed end is small, especially this prestress loss becomes more and more obvious with the increase of the tunnel length. Often the prestress cannot be fully exerted;

[0005] 3. The prestressed tendons that adopt the single-end tension method are prone to uneven force. In general engineering, when the prestressed tendons are curved, they need to be stretched at both ends. Even if the prestressed tendons are straight, the length When it exceeds a certain value, tensioning at both ends is also required, especially for the prestressed tensioning of long-span bridge and tunnel engineering, there are many methods of double-end tensioning, but the friction test is still limited to the single-end tensioning method ;

[0006] In addition, for the double-end symmetrical tensioning method often used in bridge and tunnel engineering, it is often due to the parameters of the tunnels at both ends of the double-end tensioning, or the elongation of the prestressed tendons at one end and the other end during the tensioning process. The center point shifts, resulting in inaccurate measurement data of the friction test

[0007] Therefore, in order to solve the above problems, a simplified prestressing test method with high efficiency, low cost and high accuracy is proposed to solve the problem that the traditional friction test can only perform single-end tension and double-end tension center point offset The resulting prestress loss, through the algorithm, only the prestressed tendons of a single channel are needed to solve the friction parameters and pipeline deviation parameters when the two ends are stretched

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