In the building construction, steel bar is an indispensable material, and steel bar joints are an important part to connect steel bars in construction. According to different connection strength requirements and connection methods, couplers can be divided into first-level joints, second-level joints, and third-level joints. What is the difference between them?

1. Different mechanical properties

Grade I joint: the tensile strength of the joint is greater than or equal to the actual tensile strength of the steel bar to be connected or 1.10 times the standard value of the tensile strength of the steel bar, and it has high ductility and repeated tension and compression properties;

Class II joint: the tensile strength of the joint is not less than the standard value of the tensile strength of the connected steel bar, and has high ductility and repeated tension and compression properties;

Grade III joint: The tensile strength of the joint is not less than 1.25 times the standard value of the yield strength of the steel bar to be connected, and has certain ductility and repeated tension and compression properties.

2. Different joint percentages

There is no limit range for the joint percentage of Class I joints unless there are special requirements;

The percentage of joints of grade II joints shall not be greater than 50%;

The joint percentage of Class III joints shall not exceed 25% in the same joint section.