ATTEN: Manager Liu
ADD: Longhua Development Zone, Jing County, Hengshui City, Hebei Province
(1) The thread head, tooth shape and pitch for processing steel bar threads must be the same as the connection sleeve tooth shape and pitch, and be qualified by matching gauges. 2) Water-soluble cutting wetting fluid should be used when processing steel bar threads; when the temperature is below 0 C, 15% - 20% sodium nitrite should not be used as wetting fluid or without wetting fluid sleeve (3) Operators should check the appearance quality of steel bar head one by one and make operator marks. 4) After self-inspection, qualified wire heads should be randomly sampled for 10% of each specification, and no less than 10. If one of them is unqualified, the unqualified wire heads should be re-processed and can be used after re-inspection. The qualified wire heads should be protected and put on protective caps, and be neatly classified and used according to specifications. The advantages of the connection methods are as follows: 1) good mechanical properties, safe and reliable connection: due to the rolling forming of the end of the reinforcing bar and the cold working treatment of the reinforcing bar material, the thread and the new strength of the steel are both higher, which makes up for the influence of the bottom diameter of the exposed thread smaller than the base circle diameter of the reinforcing bar on the strength weakening, and makes the joint strength of the connection stronger than the strength of the base circle of the reinforcing bar material give full play to its strength and ductility. 2) The connection is convenient in narrow The ground steel bars can be flexibly operated in dense places.
Convenient and efficient construction: steel bar connection concubine tube in factory prefabricated quality assurance: on-site rolling head set supervision for each class of Machinable joints has incomparable potential in large-scale projects and basement floor construction, no pollution, no open fire operation, good safety and environmental protection, all-weather construction 3) Easy to detect: construction does not need: With special testing equipment, the quality of the joint can be determined only by looking at the exposed teeth of steel bars. Applicability is applicable to shear seismic and non-seismic reinforced concrete structure engineering, and for bending bismuth bars, national steel bars, steel cages, super-long steel bars and other occasions can not rotate. In the late 1980s, by introducing advanced mechanical connection technology from abroad and the continuous efforts of experts from some scientific research institutes in China, the mechanical connection technology of reinforcing steel bar in China developed rapidly. Mechanical connection has undergone sleeve cold extrusion, taper mule thread, upsetting straight thread and rolling straight thread, etc. until now, the technology has been mature and stable, and the cost has been reduced.
The overlap connection method can not be used for the connection of large steel bar. In addition, there are many shortcomings in welding, so the welding quality can not be guaranteed. The mechanical connection of reinforcing bar can avoid all these difficulties and show obvious advantages. In the past ten years, I have made great progress in the mechanical connection technology of steel bar. As a new mechanical connection method, extrusion connection is reliable in performance, stable in quality, not affected by climate and welder's technical level, fast in connection, safe, no open fire, compared with traditional lapping and welding. The advantages of reliable connection between weldable and non-weldable reinforcing bars are no need of high power supply. The sleeve extrusion connection has been widely praised in many major projects such as high-rise buildings, large-span bridges, benchmark beams, hydraulic structures, TV towers, nuclear power plants and so on. There is still a certain gap between the cone-mule connection technology of our country and that of foreign countries. One of the most prominent problems is that the pitch is single, and mules are used from 16 to 40 mm steel bars in diameter. The distance is 2.5mm, and the distance of 2.5mm mule is the most suitable for the connection of 22mm steel bar.
Although there are still gaps in some aspects, these gaps will be minimized with the continuous maturity of Chinese sleeve production technology. When deepening the design, we should pay attention to: first, the set of simple welding positioning for workshop, so the positioning accuracy is very high. The basic error does not exceed 1~2 mm. Second, sleeve steel column welded sound stiffening plate 3.2.4 steel bar connection requirements (1) When connecting steel bar, steel bar specifications and connection sleeve specifications are the same, the form of steel bar threads, mule pitch, thread diameter should be matched with the connecting concubine. And ensure that the thread of the reinforcing bar connecting sleeve is clean and intact. (2) When connecting the reinforcing bar, the reinforcing bar should be screwed into the connecting sleeve by the alignment axis. After joint splicing is completed, the two silk heads should be tightened at the central position of the sleeve, and the number of exposed buttons of the extended joints with no more than one complete silk buckle at each end of the wife barrel is not limited, but there are obvious marks to check whether the length of the silk heads entering the sleeve meets the requirements. The joint area of steel bar and steel column is very complex, and three methods are needed to be used in the deepening design.
Attention should be paid to the treatment of joints: Firstly, steel plate is exhausted to avoid encountering the rigid steel column, and bending around or directly bending anchor can be used appropriately. [The length of bending anchor is shown in the concrete design code]. Secondly, when reinforcement is unavoidable, it is necessary to arrange these reinforcements appropriately. The minimum spacing of general reinforcement is 1.5D and the minimum is not less than 25mm. According to the principle, the cloth needs reinforcing bars running through the web and reinforcing bars connected with the ridge. Thirdly, the steel bar penetration direction only meets the web, so the first way should be chosen to penetrate the connection. Generally, due to the limitation of the section and the number of openings, the same row of steel bars runs through at most one side of two (cross-section of columns). When the reinforcing bars run through the web and flanks, the second bracket welding method can be used if only one row of reinforcing bars is available; if the reinforcing bars are in two or more rows, the third concubine bars will be used in the front rows.