Ultrasonic method for real-time detection of uniform hoop binding force of circular concrete filled steel tube columns

Abstract

The invention discloses a method for ultrasonic real-time detection of uniform hooping constraint force of a circular steel tube concrete column. When the axis of the circular steel tube concrete column is pressed, the hoop constraining force is uniformly distributed along the cross section of the column. The method is based on an ultrasonic stress test technology. A pair of ultrasonic transmitters and receivers is used for detecting the binding force of the hoop. An ultrasonic transmitting sensor is pre-embedded in the center of a cross section needing to be measured in the column to transmitultrasonic waves. An ultrasonic receiving device is arranged on the outer surface of a steel pipe with the same cross section to receive a test signal, and then the hoop constraint force generated when the axis of the round steel pipe concrete column is pressed is detected in real time according to the relation between received ultrasonic sound-stress sensitivity parameters and the hoop constraint force. The method is simple to operate, intuitive in measurement result, simple in test device and high in sensitivity, can realize real-time measurement of the hoop constraint force in the whole stress process, realizes real-time detection of the hoop constraint force in the construction or service process, and can also realize real-time monitoring of the safety and health of the structure.

Description

Technical field [0001] The invention relates to the technical field of ultrasonic nondestructive testing, in particular to a method for ultrasonic real-time detection of the uniform hoop binding force of a circular steel tube concrete column. Background technique [0002] Concrete-filled steel tube columns are being used more and more widely in practical engineering due to their high bearing capacity, good seismic performance, better fire resistance than steel structure and convenient construction. The bearing capacity of concrete-filled steel tube columns can produce "1+1> 2" effect, the most important reason is that the steel tube restrains the core concrete, which makes the core concrete in a three-way compression state, thereby improving the compressive strength of the concrete. Therefore, the determination of the restraint force It is very important to study the mechanical properties of concrete-filled steel tube columns. [0003] At present, the methods used to directly m...

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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 the direct detection of the binding force of the hoop of circular concrete filled steel tube columns.

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