Method for nondestructive measurement of active and passive constraint forces of FRP confined concrete column based on ultrasonic wave

Abstract

The invention discloses a method for nondestructive measurement of active and passive constraint forces of an FRP confined concrete column based on ultrasonic waves. The method is based on an ultrasonic stress test technology. The method comprises: pre-embedding an ultrasonic transmitting sensor in the center of a cross section needing to be measured in the column to transmit ultrasonic waves; arranging an ultrasonic receiving device on the outer surface of the FRP of the same cross section to receive the test signal, and measuring the active and passive constraining forces of the FRP confinedconcrete column under pressure according to the relationship between the received acoustic-stress sensitivity parameter and the hoop constraining force. The method is simple to operate, visual in measurement result, free of damage to components and high in sensitivity, can realize real-time measurement of the active constraint force and the passive constraint force in the whole stress process ofthe FRP confined concrete column, realizes real-time detection of the hoop constraint force in the construction or service process, and can realize real-time monitoring of the safety and health of thestructure.

Description

technical field [0001] The invention relates to the technical field of ultrasonic nondestructive testing, in particular to a method for nondestructively measuring the active and passive binding forces of FRP-confined concrete columns based on ultrasonic waves. Background technique [0002] Fiber-reinforced composite (FRP) confined concrete column is a new type of composite column formed by wrapping FRP on the outside of ordinary concrete columns. Since the internal concrete is in a three-dimensional stress state under the constraint of external FRP, the FRP-confined concrete column It has high bearing capacity and good axial ductility. At the same time, the external FRP can protect the internal concrete so that the FRP-confined concrete column has good durability. Therefore, the FRP-confined concrete column is gradually used in engineering repair and reinforcement and new structures. . FRP-confined concrete can be divided into passive confinement and active confinement. Pas...

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Problems solved by technology

Although there have been a lot of studies on the performance of steel-tube confined concrete, recent studies have shown that the axial compressive strength model for steel-tube-confined concrete cannot be directly used for FRP-confined concr

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