Test method for measuring uniform and non-uniform constraining force of concrete filled steel tubular column by adopting piezoelectric film

Abstract

The invention discloses a test method for measuring uniform and non-uniform constraining force of a concrete filled steel tubular column by adopting a piezoelectric film. According to the invention, the piezoelectric film with the thickness of only 28 [mu]m is pasted on the inner side of the steel pipe, a hole is formed in the position 2-30 d away from the pasting surface to lead out a wire to output a piezoelectric signal, and d is the diameter of the hole, so that inaccurate measurement of the constraining force of the measurement position caused by stress concentration of the hole positionis avoided. The high sensitivity of the piezoelectric film to dynamic stress is utilized, and the interaction force between the steel pipe and concrete is measured through the change of electric signals between the upper and lower electrodes of the film. The device cannot damage the interface characteristics of the steel pipe and the concrete, and the film is thin and easy to place, the test device is simple, the measurement operation is easy to implement, the measurement result is visual, the sensitivity and accuracy are high, the actual measurement of the hoop constraint force in the whole stress process can be realized, the real-time detection of the hoop constraint force in the construction or service process is realized, and the real-time monitoring of the safety and health of the structure can be realized.

Description

technical field [0001] The invention relates to the technical field of ultrasonic non-destructive testing, in particular to a test method for measuring the uniform and non-uniform binding force of a steel pipe concrete column by using a piezoelectric film. Background technique [0002] During the compression process of CFST columns, the steel pipes will have a hoop restraint effect on the core concrete, which greatly improves the strength and ductility of the concrete. Mechanical properties play a crucial role. However, because the hoop binding force of the steel pipe to the core concrete exists on the narrow interface between the steel pipe and the concrete, the ordinary stress-strain measurement device cannot be installed, and for the square steel pipe, its binding effect on the core concrete is still weak. In a non-uniform state, it is even more impossible to install multiple measuring devices on the same cross section. Piezoelectric films are light, thin, durable, and ...

AI Technical Summary

Problems solved by technology

However, because the hoop binding force of the steel pipe to the core concrete exists on the narrow interface between the steel pipe and the concrete, the ordinary stress-strain measurement device cannot be installed, and for the square steel pipe, its binding effect on the core concrete is still weak. It is inhomogeneous, and it is even more impossible to install multiple measuring devices on the same cross section

Piezoelectric film is light, thin, durable, and can work passively. It is currently widely used in medical sensors, but there is no report on the binding force detection of steel tube concrete.

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