Method for ultrasonic nondestructive testing of non-uniform hooping constraint force of concrete-filled square steel tubular column

Abstract

The invention discloses a method for ultrasonic nondestructive testing of non-uniform hooping constraint force of a concrete-filled square steel tubular column. At present, no test method capable of accurately measuring the magnitude of the non-uniform constraint force and the distribution condition of the non-uniform constraint force along the section exists due to the fact that the hoop constraint force of the square steel tube on the core concrete is distributed in a non-uniform groove shape. Therefore, the method is based on an ultrasonic stress test technology, an ultrasonic transmittingsensor for transmitting ultrasonic waves is pre-embedded in the central position of a cross section to be measured in a column, a plurality of ultrasonic receiving devices are arranged on the outer surface of the steel pipe with the same cross section in the width direction of the cross section to receive test signals, and then, according to the relation between the received sound wave sound-stress sensitivity parameters and the hoop constraint force, the uneven hoop constraint force of the cross section along the width direction of the cross section needing to be measured when the concrete-filled square steel tubular column is pressed is detected. The method is simple to operate, and visual in measurement result; the testing device is simple and high in sensitivity, and measured componentdoes not need to be damaged; and actual measurement of the hoop constraint force in the whole stress process can be realized.

Description

technical field [0001] The invention relates to the technical field of ultrasonic nondestructive testing, in particular to a method for ultrasonic nondestructive testing of the binding force of uneven hoops of square steel tube concrete columns. Background technique [0002] Concrete-filled steel tube columns are being more and more widely used in practical engineering because of their advantages such as high bearing capacity, good seismic performance, better fire resistance than steel structures, and convenient construction. The bearing capacity of CFST columns can produce the effect of "1+1>2". An important reason is that the hoop restraint effect of the steel tube on the core concrete puts the core concrete in a three-dimensional compression state, thus improving the compressive strength of the concrete. . Therefore, the determination of the size of the hoop constraint is very important for the in-depth study of the mechanical properties of CFST columns. [0003] At ...

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Problems solved by technology

However, the core concrete in CFST is in a three-dimensional compression state, and the pressure sensor is affected by longitudinal pressure and hoop pressure under complex stress, and its sensitivity decreases. In addition, its sensitivity will also decrease after repeated loads, so it is very difficult It is difficult to popularize in practical application; while the hydraulic analog method is essentially an analog method, the test is cumbersome, the reading is not intuitive, and the accuracy is not high

At present, there is no relevant report on the application of ultrasonic testing technology to directly measure the binding force of uneven hoops of square concrete filled steel tube columns.

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