Intelligent clamping piece type anchor and prestress monitoring method based on piezoelectric impedance method

Abstract

The invention discloses an intelligent clamping piece type anchor and a prestress monitoring method based on a piezoelectric impedance method. A circular piezoelectric ceramic piece is used to post atthe free end of a steel strand, Annular piezoelectric ceramic piece is embedded in a clamping piece of the clamping piece type anchor, or a rectangular piezoelectric ceramic piece is embedded in an anchor bearing plate, so that the anchor fixing condition of the clamping piece type anchor is monitored. Pressure is produced between the steel strand and the clamping piece, between the anchor and the anchor bearing plate because of the relaxation of the prestress steel strand and other factors, the vibration frequency of a component is changed. According to the forward and inverse piezoelectriceffects of piezoelectric ceramics, and the using of an impedance analyzer, the changes of mechanical impedance values of the component are measured. A loss index is defined by extracting resonance frequency and root-mean-square deviation, and the loss index is used to identify the loose and tight anchor fixing conditions of the clamping piece type anchor. The intelligent clamping piece type anchorbased on the piezoelectric impedance method is simple in structure, can quickly and actively monitor and evaluate the loose and tight anchor fixing conditions of the clamping piece type anchor, and provides a simple and effective method for monitoring the anchor fixing of prestress steel strand in civil engineering.

Description

technical field [0001] The invention belongs to the technical field of civil engineering, and in particular relates to an intelligent clip-type anchor and a prestress monitoring method based on a piezoelectric impedance method. Background technique [0002] The emergence of prestressing technology improves the service performance of structures, improves the crack resistance and stiffness of structural components, and improves the quality of structures, and the development of prestressing technology also promotes the development of new bridge structure systems and construction methods. The key equipment for safe stress construction and reliable structure, its anchorage situation plays a decisive role in the safety of the structure, and the prestress of prestressed steel bars will inevitably decrease with the passage of tension, anchorage and time. That is, prestress loss occurs, so the monitoring of prestress loss value in design, construction and later operation is particula...

AI Technical Summary

Problems solved by technology

[0007] However, there is currently no simple and effective method for monitoring the loss of prestress. Non-destructive testing such as the jack force measurement method is the most accurate, but it is only suitable for construction, and it is difficult to achieve continuous monitoring in the later operation; destructive testing such as steel bar cutting method will prestress The external concrete structure of the beam is stripped, and some steel strands are cut off to detect the prestressed value

This method is complex to operate and will cause irreversible damage to the structure; the steel stress release method can test the stress of the structure, but the cutting speed, cutting temperature, etc. are the disturbance factors of the test stress

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