What are the mechanical connection methods of steel bars

Mechanical connection of steel bars.

1 Radial extrusion connection.

A steel sleeve is sleeved at the end of two ribbed steel bars, and the steel sleeve is radially extruded along the steel sleeve with ultra-high pressure hydraulic equipment (extrusion pliers), and under the action of the extrusion force, the steel sleeve produces plastic deformation and is closely combined with the steel bar, and the two steel bars are firmly connected together through the occlusion of the steel sleeve and the steel bar cross rib.

Features: The joint has high strength, reliable performance, and can withstand high stress and repeated tensile and compressive loads and fatigue loads. The method has been widely used in the project, such as easy operation, fast construction speed, energy and material saving, and good comprehensive economic benefits.

Scope of application: suitable for 18 50mm , grade ribbed steel bar (including poor weldability of steel bar), the same diameter or the connection between different diameter steel bars.

2 Axial extrusion connection.

It is a mechanical connection method that adopts the pressing film of the extruder, cold-extrudes the special metal sleeve along the axis of the steel bar, and tightens the two hot-rolled ribbed steel bars inserted into the sleeve.

1. If you want to connect the steel bars together, there are generally three connection methods, namely: welded connection, binding connection, mechanical connection, if the selected steel bar connection method is different, the tools and materials required for the steel bar connection, and the technical requirements for the construction personnel will be different.

2. Among them, the lashing connection is a more commonly used connection method in construction engineering at present. When the baring type continuous mu connection method is used to connect the steel bar, the two joints of the steel bar need to be lapped together first, and then the lap position can be tied with the wire binding.

3. When lapping steel bars, the length of steel bar lap will generally be relatively long, so it will lead to waste of steel bars, which will undoubtedly increase the use of steel bars and lead to an increase in construction costs. However, the construction speed of this connection mode will be faster, and the construction process will be simpler and easy to construct.

4. Welded connection method is a very commonly used method in construction engineering at present. If you use a welded connection to connect the steel bar, you can dock the two joints of the steel bar together, or lap the steel bar joints together in a small amount, and then use a welding machine to weld the butt or lap position together, so that the steel bar can form a whole. In addition, a short steel bar of about 45 cm is tied at the butt position before welding.

The mechanical connection of steel bars should be used for the connection of stressed steel bars with a diameter of not less than 16mm. The length of the connection section of the mechanical connection is the range of 35d with the sleeve as the center length, and the percentage of the area of the longitudinal tensile reinforcement joint in the same connection section should not be greater than 50%, but the splicing of plates, walls, columns and prefabricated components can be appropriately relaxed. The percentage of joint area of longitudinal compression reinforcement can be unlimited.

The mechanical connection of steel bars has the advantages of joint strength higher than that of steel bar base metal, speed 5 times faster than electric welding, no pollution, and 20% saving of steel. The common methods are as follows: (1) sleeve extrusion connection.

The sleeve extrusion connection is to insert the ends of the two steel bars to be connected into a high-quality steel casing, and then use an extruder to pressurize several channels laterally, and the sleeve is tightly occlused with the ribbed steel bar after plastic deformation to achieve the purpose of connection.

2) Cone and thread connection. The tapered thread connection is to use a tapered sleeve to dock the ends of two steel bars together, and use the mechanical occlusion force of the thread to transmit tension or pressure. The equipment used is mainly a threading machine, which is usually placed on site to thread the end of the rebar.

3) Straight threaded connection. The straight thread connection is to first upset the end of the steel bar, then cut the straight thread, and finally use the sleeve to implement the steel bar butt. The straight thread joint has high strength and is not affected by the torsion torque; The connection is fast.

1. The processed steel bar connection and sleeve wire are not less than 11 buckles, and the sleeve length has requirements, such as 25 threaded steel bars of 60mm (, and the test results meet the requirements of the specification.

2. The processing tolerance of the wire head should be grinding.

3. After installation, the external leakage thread should not exceed 2p.

4. The end of the steel bar should not exceed 10mm from the center point of the sleeve length, and the length of the thread = 2 d + the length of the sleeve).

When the longitudinally stressed steel bars in the concrete component are welded or mechanically connected, the provisions of a connection section are:Welded joints where the midpoint of the joint is within the length of the connection section belong to the same connection section.

The length of the join segment:The welded joint is 35d and not less than 500mm

i.e. 500mm), d is the smaller diameter of the connecting rebar; The mechanical connection is 35d

d is the smaller diameter of the connecting reinforcement.

8. 4.7. The mechanical joints of the longitudinally stressed steel bars should be staggered with each other.

The length of the mechanical connection section of the reinforcement is 35d, and d is the smaller diameter of the connecting reinforcement. Any mechanical connector where the midpoint of the connector is within the length of the connection section belongs to the same connection section.

The percentage of the area of the longitudinal tensile reinforcement joint located in the same connection section should not be greater than 50%; But on the board、

The splicing of walls, columns and prefabricated components can be relaxed according to the actual situation. The percentage of joints of longitudinally compressed steel bars can be unlimited.

The thickness of the protective layer of the mechanical connection sleeve should meet the provisions of the minimum protective layer thickness of the steel bar. The transverse net spacing of the mechanical connection sleeve should not be less than 25mm; The spacing of the stirrups at the sleeve should still meet the corresponding structural requirements.

In addition to the fatigue resistance required by the design, the percentage of the area of the longitudinally stressed reinforcement joints located in the same connection section should not be greater than 50%.

8. 4.8. The welding of fine-grained hot-rolled ribbed steel bars and ribbed steel bars with a diameter greater than 28mm should be determined by testing; Waste heat treatment steel bars should not be welded.

The welded joints of the longitudinally stressed steel bars should be staggered from each other. The length of the connecting section is 35d and not less than 500mm, d is the smaller diameter of the connecting bar, and all welded joints with the midpoint of the joint within the length of the connection section belong to the same connection section.

The percentage of the joint area of the longitudinal tension reinforcement should not be greater than 50%, but the splicing of prefabricated components can be relaxed according to the actual situation. The percentage of joints of longitudinally compressed steel bars can be unlimited.