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Steel bar straight thread connection process
Reinforcement straight thread connection process summary: Reinforcement connection adopts straight thread connection, the sleeve is prefabricated outside the site, and the construction method of on-site connection is used. All steel bars are processed on-site. For on-site processing personnel entering the site
Steel bar straight thread connection process
(1) Construction preparation
The steel bars are connected by straight threads, the sleeves are prefabricated outside the site, and the construction methods are connected on site. All steel bars are processed on site. For the on-site processing personnel entering the site, training is required. After the completion of the on-site assessment, the qualified personnel will be issued a job certificate, and the construction personnel will be on the job with a certificate. Non-professional operations are strictly prohibited.
(2) Process flow and key points of operation
Blanking → threading → spot check 10% with thread gauge → (after passing) wear plastic protective caps → sort and stack → transport to the site for backup → use sleeves to butt steel bars → tighten and position with a wrench → check the exposed wires at both ends of the sleeves Buckle not more than one full buckle → On-site inspection and records
Rebar blanking requires straight ends and no horseshoe shape.
The threading workers should be relatively fixed, and they should hold a certificate after training. Threading workers should visually check the quality of threading one by one, and randomly check 10% of the thread heads, and check with thread gauges.
When threading, lubricating fluid must be added for threading.
The diameter and length of the processed steel wire head should be checked with a thread gauge and kept within the specified fluctuation range.
When connecting steel bars on site, the steel bars at both ends of the sleeve should be pressed against each other, and the center position of the sleeve should be kept, and the exposed buckles at both ends should not exceed one complete thread.
(3) Steel connection
Check whether the type of the sleeve and the steel bar are consistent, check whether the threaded fastener is intact, clean, and remove impurities and rust. When the steel bars are connected, pay attention to the tightness of the two steel bars so that the exposed tooth profile does not exceed a complete thread. After the construction is completed, mark the joints that have passed the inspection with red paint.
50% of the steel bar connection of the bottom plate is considered to be overlapping, and the position of the lower iron joint should be avoided as far as possible from the place where the maximum bending moment of the support is reached;
Beam steel bars are connected to the upper iron in the middle 1/3 section of the span, and the lower iron is connected to the support 1/3 section; after the connection is completed, special personnel will inspect it.
Column reinforcement connection: The distance between the column reinforcement connection joint and the ground is greater than 500mm, and the positions of the two joints are staggered by 35d. After the steel bars are connected, a special person will check them.
Sampling is carried out on-site for the steel bar joint test, and the quality and representativeness of the samples are guaranteed during sampling to ensure a 100% qualified rate of joints.
(4) Quality standards
The variety and quality of steel bars must meet the design requirements and current national standards. Inspection method: There must be a factory quality certificate and a test report.
Requirements for sleeves:
There are no cracks and other defects on the surface of the sleeve;
External dimensions including sleeve internal thread diameter and sleeve length meet product design requirements;
Plastic protective caps should be added to both ends of the sleeve.
Requirements for thread heads:
After passing the inspection, the wire heads should be put on plastic protective caps as soon as possible, and they should be stacked neatly according to the specifications;
In the case of rainy season or long-term stacking, the silk head should be covered to prevent rust;
The thread head should be properly protected during transportation to avoid rain and mechanical damage.
The strength of the joints must be qualified, and less than 500 joints are considered as one batch, and three test pieces are made for each batch for tensile test. Inspection method: check the joint tensile test report.
The specifications of the steel bars, the location of the joints, and the percentage of the area of the steel bars with joints in the same section shall not exceed 50%. Inspection method: on-site observation and statistics.
(5) Quality issues that should be paid attention to
Before the steel bar is threaded, the specification and appearance quality of the steel bar must be checked. If the end of the steel bar is found to be bent, it must be straightened first.
Rebar threading: Before operation, the position of the positioning ruler should be adjusted, and the corresponding processing guide sleeve should be equipped according to the specifications of the rebar. For large-diameter steel bars, the specified size should be cut in stages to ensure the accuracy of the thread.