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Method for testing value of bonded prestress released after pre-reinforcement of existing structure

A technology of bonding prestressed and existing structures, applied in the direction of measuring force, measuring devices, instruments, etc., can solve problems such as waste of resources, inaccurate test results, and damage to prestressed tendons, so as to reduce excessive strength loss and avoid The effect that the measured data is too small and the measured data is accurate

Active Publication Date: 2022-03-29
CENT RES INST OF BUILDING & CONSTR CO LTD MCC GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there is no mature and feasible engineering method for bonded prestressed structures; if the measured prestress value is too high, it will affect the safety of the structure, and if the measured value is too low, it will cause waste of resources
[0004] In engineering, the stress release method is usually used as the measurement method of bonded prestress. Generally, the concrete stress release method or the stress release of ordinary steel bars is used. By releasing the stress in ordinary steel bars or concrete, the stress in prestressed tendons is estimated by using deformation coordination. , is an indirect measurement method, because there is a complex stress-strain relationship in the concrete structure, and there is no direct measurement of the bonded prestressed tendon itself, so the test result is inaccurate
The stress of the prestressed tendons is directly released, that is, the direct stress value obtained by directly cutting off the bonded prestressed tendons, so the measured value is accurate, but because the stress release will cause irreversible damage to the prestressed tendons, release Afterwards, it may cause greater damage to the component, which is not easy to use

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  • Method for testing value of bonded prestress released after pre-reinforcement of existing structure
  • Method for testing value of bonded prestress released after pre-reinforcement of existing structure
  • Method for testing value of bonded prestress released after pre-reinforcement of existing structure

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Embodiment 1

[0041] This embodiment provides the bonded prestress value test method released after the pre-reinforcement of the existing structure, refer to Figure 1 to Figure 2 , the existing structure includes a concrete structure 1 and bonded prestressed tendons 4, and the bonded prestressed tendons 4 and the concrete structure 1 are bonded together.

[0042] Specifically, the bonded prestressed tendons 4 are first placed in the reserved channels of the concrete structure 1, and after being tensioned and anchored, they are bonded with the surrounding concrete through grouting, so that the adhesive The prestressed tendons 4 are closely combined with the surrounding concrete, which improves the strength of the concrete structure 1; the concrete structure 1 is provided with a plurality of bonded prestressed tendons 4, and the bonded prestressed tendons 4 are all placed in the reserved tunnel, and after being tensioned and anchored, they are integrated with the surrounding concrete through...

Embodiment 2

[0053] This embodiment provides a method for measuring the stress value of bonded prestressed tendons released after the pre-reinforcement of the existing structure. Figure 1 to Figure 2 , the measurement method includes the steps of:

[0054] S1: chiseling the concrete structure in the 4 measuring point area with bonded prestressed tendons, and removing the structure so that the length of the exposed bonded prestressed tendons is greater than or equal to 30 cm;

[0055] S2: Grind the bonded prestressed tendons at the end of the bonded prestressed tendons 4 until the flat and smooth surface of the steel strand is exposed, and the upper and lower surfaces of the steel strand are along the prestressing direction on the symmetrical sides pasting two pieces of the first strain gauge 2;

[0056] S3: setting a cutting device at 10-20 cm of the first strain gauge;

[0057] S4: Grinding the bonded prestressed tendons 4 at the position of the bonded prestressed tendons 4 on the oppo...

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Abstract

The invention relates to a method for testing the value of bonded prestress released after pre-reinforcement of an existing structure, and belongs to the technical field of prestress measurement in civil engineering, the device comprises a concrete structure body, bonded prestressed tendons, a first strain gauge, a second strain gauge, a third strain gauge and a fourth strain gauge, at least one first strain gauge is bonded on the bonded prestressed tendon and is bonded along the prestressed direction; the carbon fiber sheet is adhered to the surface of the bonded prestressed tendon, and the carbon fiber sheet is adhered to one side opposite to the cutting device; the bonded prestressed tendons are pre-reinforced by the carbon fiber sheets; and the second strain gauge is bonded on the carbon fiber sheet and is bonded along the pre-stress direction. The method has the advantages that the prestress value can be accurately measured, and the strength of the prestressed tendon cannot be greatly weakened.

Description

technical field [0001] The invention relates to the technical field of prestress measurement in civil engineering. More specifically, the invention introduces a method for detecting the stress value of bonded prestressed tendons in service by using carbon fiber sheets to first reinforce and then release stress. Background technique [0002] The prestress value in the prestressed structure is directly related to the service state and safe operation of the structure. In the long-term use of the structure, the prestress will be lost with the service time and development, and the stress value in the prestressed tendon will gradually decrease. . In the process of structural performance evaluation and reconstruction and reinforcement, it is necessary to measure the stress value in the prestressed tendon to determine the current prestress value state, so as to better determine the performance of the structure. [0003] For unbonded prestressed structures, there are relatively matu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01L1/22B21F11/00
CPCG01L1/22G01L1/2206B21F11/00
Inventor 徐曼曾滨张灏达尚仁杰许庆
Owner CENT RES INST OF BUILDING & CONSTR CO LTD MCC GRP
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