The parallel thread rebar coupler is a steel sleeve for the mechanical joint which transmits the axial tension or pressure of the steel bar. The connection method of the parallel threaded rebar coupler is to strip off part of the longitudinal rib and transverse rib of the end of the steel bar by cutting with a wire rolling machine, and then roll directly into ordinary parallel thread, and connect with the special parallel rebar coupler to finish the connection of the steel bar. So, how do we check its connection quality?

1. Appearance inspection of construction quality:

(1) Check whether the crimping pattern conforms to the plan, why the coupler rusts, and whether the coupler is under pressure. The small indentation of the joint shall conform to the standard.

(2) There should be no visible cracks on the appearance of the joint. 

(3) The curvature of the joint is 40.

(4) At both ends of the joint, the steel bars have inspection marks.

(5) During the appearance inspection, three samples were extracted from the joints for the tensile test. If the strength of one of the specimens is lower than the planned value, then the batch of joints is unqualified.

2. If there is still one unqualified specimen in the reinspection, this batch of joints is unqualified. The 500 joints of the same grade, the same material, and the same construction conditions shall be one inspection batch, and the less than 500 joints shall also be one batch. Identify three randomly selected samples from each batch of test pieces. When the unidirectional tensile test results of the three specimens meet the requirements in JGJ107-96, the joints are qualified. If the tensile strength of one specimen does not meet the requirements, six specimens should be re-examined.

The above is the correct way to check whether the quality of the parallel rebar coupler is qualified.