Structure and method for measuring prestress transmission length and bonding anchoring strength through optical fiber method

Abstract

The invention discloses a structure and a method for measuring the prestress transmission length and the bonding anchoring strength through an optical fiber method. The structure comprises a concretetest piece, a pressure bearing plate, an intelligent steel strand, a force application assembly and an optical fiber grating measuring instrument. Tension is applied to the intelligent steel strand through the force application assembly, the maximum tension is divided into 10 levels, 10% of the maximum tension is applied each time, and the pressure value and the strain value of the fiber bragg grating measuring instrument are read. When the tensioning force reaches the maximum tensioning force, the prestress transmission length is formed between the tensioning end and the grating measuring point generating strain and between the tensioning end and the grating measuring point not generating strain, and the shear strength namely the bonding and anchoring strength between the concrete test piece and the intelligent steel strand is calculated and obtained. The fiber bragg grating intelligent steel strand is utilized, the prestress transmission length and the bonding anchoring strength between the prestress intelligent steel strand and concrete are accurately measured, the measurement error is small, the technical precision requirements of engineering design and construction are met, and more accurate data are provided for prestress concrete structure design and construction.

Description

Technical field [0001] The invention relates to the technical field of prestressed concrete in the field of civil engineering, and more specifically relates to a structure and method for measuring the prestress transmission length of a prestressed steel strand and the bonding and anchoring strength between the steel strand and concrete. Background technique [0002] Concrete is a brittle material with high compressive strength. The tensile strength is only about 1 / 10 of the compressive strength. Therefore, the use of high-strength prestressed steel strands to prestress the concrete can effectively improve the crack resistance of the concrete structure. Performance, to avoid excessive concrete cracks, and even control the concrete structure not to crack. Pre-tensioning technology is divided into pre-tensioning method and post-tensioning method. Post-tensioning method includes bonded, non-bonded and retard-bonded pre-stressing technology. Generally, it can be divided into 4 categor...

AI Technical Summary

Problems solved by technology

[0003] However, it has always been very difficult to accurately measure the distance between the prestressed steel strand and the concrete to achieve anchorage without anchorage. If the strain gauge is attached to the steel strand, the prestressed tendon will A slight deformation will destroy the measuring point of the strain gauge. Therefore, it has always been a technical problem in the industry to accurately measure the prestressed transmission length of the prestressed steel strand and the bond and anchorage strength between the prestressed steel strand and concrete.

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