There are three connection methods for reinforcing steel bars: welding, mechanical connection and lashing connection.

(2) Welding of steel bars:

Commonly used welding methods are: flash butt welding, arc welding (including bar welding, lap welding, groove welding, groove welding, fillet welding and plug welding, etc.), electroslag pressure welding, air pressure welding, Submerged arc pressure welding, etc.

In structural members that directly bear dynamic loads, welded joints should not be used for longitudinal reinforcement.

(3) Reinforcing steel mechanical connection: There are steel sleeve extrusion connection, steel straight thread sleeve connection (including steel upsetting straight thread sleeve connection, steel bar stripping and rolling straight thread sleeve connection) and other methods.

At present, the most common and most used method is the steel bar stripping and rolling straight thread sleeve connection. The generally applicable steel bar grades are HRB335, HRB400, RRB400; the applicable steel bar diameter range is usually 16-50mm.

(4) Rebar lashing connection (or lap joint):

When the diameter of the tension steel bar is greater than 25mm and the diameter of the compression steel bar is greater than 28mm, it is not suitable to use lashing lap joints.

The longitudinally stressed steel bars of axial tension and small eccentric tension members (such as the tie rods of trusses and arches, etc.) shall not use lashing lap joints.

(5) The joint position of the steel bar should be set at a place where the force is small. Two or more joints are not suitable for the same longitudinally stressed steel bar. The distance from the end of the joint to the bending start point of the steel bar shall not be less than 10 times the diameter of the steel bar. The number of reinforcement joints in the same section of the component shall meet the design and specification requirements.

(6) At the construction site, specimens of mechanical connection joints and welded joints of steel bars shall be taken for mechanical performance inspection according to current national standards, and their quality shall comply with the provisions of relevant regulations.