■ ** The standard JGJ107-2010 "Technical Specifications for the Mechanical Connection of Steel Bars" stipulates that in a unidirectional tensile test, the deformation performance level of the joint is required when the two steel bars are mechanically connected through a cylindrical sleeve: residual deformation u0≤ 0.10mm (rebar diameter d≤Φ32mm) and u0≤0.14mm (rebar diameter d> Φ32mm). The residual deformation measured in actual work is generally between 0.030mm and 0.080mm. The amount of residual deformation is small.
■ The data of the steel bar residual deformation tester is accurate only when it is measured by a double-sided extensometer;
■ Only elastic connection between extensometer and rebar (for example: spring and rubber band), the data obtained by this measurement is reliable. Many experiments have proved that although the mechanical rigid connection is convenient for connection, the measured data has a large error, greater than 1%, poor repeatability, data A is reliable, and cannot pass the measurement verification.
Second, the main indicators of the residual deformation detector
■ Meet the standard: JGJ107-2010 "Technical Regulations for Mechanical Rebar Connections" (implemented on 2010.10.01)
■ Calibration instrument: GWB-200B high precision extensometer calibrator (range 0 ~ 25mm, resolution 0.0002mm) Manufactured by Central Iron and Steel Research
■ Diameter of reinforcement (mm): φ5 ～ φ40
■ Measurement resolution (mm): 0.001
■ Accuracy level: 1 level
■ The meaning of the digital display:
Mean: The average value of PV1 and PV2
PV1: the deformation measurement value of the A-channel extensometer
PV2: indicates the deformation measurement value of ** road extensometer
Third, the main characteristics of the steel bar residual deformation tester
■ Residual deformation tester for mechanical connection of steel bars consists of two high-precision variable-gauge extensometers with the same sensitivity. It consists of two-sided extensometers, which directly measure the average deformation of the two sides of the sample, and the measurement results are accurate;
■ The measurement distance of two extensometers is adjustable, ranging from 50 to 260mm, and the range is 5mm or 10mm;
■ Four-digit, three-row, two-input high-precision digital display meter, the circuit part adopts 24-bit A / D high-precision IC chip design, real-time display of the real deformation of the two extensometers, and the values are stable and reliable;
■ The digital display meter is simple to set and has a password lock setting function to avoid misoperation to change the setting value;
■ The elastic connection between the extensometer on both sides and the steel bar (such as spring and rubber band cover) is convenient for sample clamping and long service life;
■ This instrument is carefully designed by ** personnel according to the actual situation, and the structure is reasonable, which is very suitable for testing and use by the building quality inspection department.
Fourth, the main configuration of the residual deformation detector
■ Two variable gauge extensometers;
■ One high-precision digital display meter;
■ One set of commonly used tools;
■ One instruction manual;
■ Instrument packing box (340 × 230 × 110mm).