What are the ways of longitudinal stress reinforcement connection and what are the advantages and di

Rebar connectionsThere are three main ways: lashing lap joint, mechanical connection and welding.

Advantages and disadvantages: Lashing lap connection is a way to transmit the stress of the reinforcement by the adhesive force between the reinforcement and the concrete. The two opposite reinforcements are anchored in the concrete of the lap connection section and the force is transmitted to the concrete, so that the stress between the reinforcements is transmitted.

A welded connection is a direct force transfer between the stressed steel bars through molten metal. Force is transmitted directly between the steel bars through the molten metal. If the welding quality is reliable, there are no defects in strength, stiffness, recovery performance, damage performance, etc., which is a very ideal connection method.

Mechanical connection is a kind of steel bar connection method developed in recent years, which realizes the force transmission of steel bars through a sleeve that is coherent between two steel bars, and is a form of indirect force transmission. The force transfer between the steel bar and the sleeve can be achieved through the crushing of the deformation of the squeezing, the wedge between the threads, and the infusion of high-strength cementitious materials.

of gluing and other forms of realization.

Principle. 1. The joint should be set up in the place where the force is less as far as possible, and the key parts of the structure with greater force should be avoided. Avoid beam ends and column end stirrups in seismic design.

Encryption range, if it must be connected in this area, it should be mechanically connected or soldered.

2. In the same span or the same floor height, there should be fewer connecting joints on the same stressed steel bar, and 2 or more joints should not be set.

3. The position of the joints should be staggered with each other, and the percentage of the joint reinforcement area should be within the connection range.

It should be limited to a certain range.

4. Necessary structural measures should be taken in the reinforcement connection area to stress the reinforcement in the longitudinal direction.

Transverse structural reinforcement or stirrups should be configured within the lap length.

5. The longitudinal stress reinforcement of axial tension and small eccentric tension rods (such as trusses and arch tie rods) shall not be used for lashing lap joints.

Generally, there are three types:

Lashing lap joint: convenient and fast, but it is a waste of steel, and the diameter is 28mm or under special circumstances (tension), it should not be used;

Mechanical connection: reliable quality and time-consuming.

Welding: convenient, save steel, should not bear dynamic load.

There are three types: mechanical, welding, and lashing. Due to the different characteristics of each connection method, the equipment used is different, and the skill requirements for the construction personnel are also different, so we should choose the appropriate connection method according to the actual situation before connecting the steel bar, so as to ensure that the steel bar connection has good durability.

What to pay attention to when connecting reinforcing bars.

Connection.

When choosing the welding method, it is recommended that the construction party should focus on flash butt welding. If the diameter of the steel bar used is less than 25mm, the way of binding connection can be adopted; If the diameter of the steel bar used is between 28-32mm, the sleeve connection can be adopted; If the steel bar in the tie rod is used, regardless of the diameter of the steel bar, it is necessary to use a welded joint.

Temperature requirements for welding.

Before the welding connection is adopted, the required steel bar must be transported to the workshop for welding in advance, and after the steel bar is welded, let it be left for a period of time for natural cooling, and the steel bar can be completely cooled before construction. The connection of steel bars can not be carried out in bad weather, if it encounters wind, rain or snow, it is necessary to do corresponding protection and insulation measures for the welded joints of the steel bars, and the welded joints must not be in contact with ice and snow.

Rebar joints.

When connecting, a certain distance should be maintained between the joints of the steel bar, and the joints should not be deformed, there are gaps and other problems, so as not to affect its strength and tensile resistance.

The anchorage length is related to the design value of the tensile strength of the anchor reinforcement (proportional), the design value of the concrete tensile strength of the anchoring area (inversely proportional), and the shape coefficient of the anchor reinforcement (proportional, the smooth reinforcement is and the diameter of the ribbed reinforcement (proportional).

When the percentage of longitudinal reinforcement lap joint area determines the correction coefficient of longitudinal stressed reinforcement, when it is a different value, the length of the stressed reinforcement lap joint lle= lae is different, when the percentage of longitudinal reinforcement lap joint area is 25% =, when the percentage of longitudinal reinforcement lap joint area is 50% =, when the percentage of longitudinal reinforcement lap joint area is 100% =.

The inspection of the reinforcement and the process inspection of the reinforcement joint:

The inspection of the steel bar should first check the brand number and quality certificate of the steel bar; Secondly, it is necessary to do a visual inspection, extract 5% from each batch of steel bars, check that there shall be no cracks, wounds and stacks on its surface, the bump on the surface of the steel bar shall not exceed the height of the transverse rib, the depth and height of the defect shall not be greater than the allowable and deviation of the part, and the bending of each meter of the steel bar shall not be greater than four millimeters.

Next, if each batch is less than 60 tons, 2 will be extracted from it, and two sections of each will be intercepted for tensile and cold bending tests respectively. 100 500mm at both ends of the steel bar should be removed when the specimen is intercepted, and the corresponding steel bar should be taken when the specimen is more than 60 tons. If the results of one test do not meet the requirements, double the number of samples from the same batch is taken for each test.

If there is still a sample that is unqualified, the batch of steel bars is unqualified, and the hot-rolled steel bars are brittle, poor welding performance or significantly abnormal mechanical properties during the processing process, and chemical composition analysis and other special inspections should be carried out.

Lap lengths are only available for lashing connections. When you say lashing, welding, and mechanical connection, you mean the way the steel bar is connected, not lapped.

1. Binding method:

Advantages: 1. Simple construction;

2. High efficiency;

3. Do not damage the steel bar.

Disadvantages: too much waste of rebar; The skeleton is prone to deformation.

2. Electric welding:

Advantage 1: The steel frame is firm and not deformed;

2. Save steel bars.

Disadvantages: 1. Damage to steel bars;

2. Energy consumption. 3. Spiral joint method:

Advantage 1, no damage to the steel bar;

2. High degree of specialization (standard); It is simple, too.

Disadvantages: 1. Troublesome process;

2. The installation is inconvenient;

3. Energy consumption.

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1. Binding method:

Advantages: 1. Simple construction;

2. High efficiency;

3. Do not damage the steel bar.

Disadvantages: too much waste of rebar; The skeleton is prone to deformation.

2. Electric welding:

Advantage 1: The steel frame is firm and not deformed;

2. Save steel bars.

Disadvantages: 1. Damage to steel bars;

2. Energy consumption. 3. Spiral joint method:

Advantage 1, no damage to the steel bar;

2. High degree of specialization (standard); It is simple, too.

Disadvantages: 1. Troublesome process;

2. The installation is inconvenient;

The first is the lashing, this is mainly convenient, the cost is relatively low, but the scope of application can only be used for small steel bars, for large ones are easy to misplace, and then the adhesion between the steel bars is better in this way of mechanical connection, and the construction is convenient for a wide range of applications, but the cost is better, and then it is welding, connected with machinery, but Shi Hong is inconvenient.

The longitudinally stressed steel bars of axial tension and small eccentric tension members should be mechanically connected or welded. The diameter of the tensile steel bar is greater than 25mm, and the compression steel bar or the diameter of the steel bar is greater than 28mm should be mechanically connected or welded.

The longitudinal stress reinforcement of axial tension and small eccentric tension liquid envy members shall not be lashed and lapped; When the steel bars in other components are tied and lapped, the diameter of the tensile steel bar should not be greater than 25mm, and the diameter of the compression steel bar should not be greater than 28mm.