Expansion bolt is generally said to be metal expansion bolt. Its fixation principle is to use wedge angle to promote expansion to produce friction and binding force, so as to achieve the fixation effect. The bolt is threaded at one end and tapered at the other. There is a sheet of iron (some are steel pipes) on the outside. Half of the sheet cylinder (steel pipe) has several incisions. They are put into the holes made on the wall together, and then the nut is locked. The nut pulls the screw outward to pull the taper into the sheet cylinder. The sheet cylinder is expanded and then firmly fixed on the wall. It is generally used for protective fence, awning, air conditioning, elevator, building curtain wall, etc The fastening of Metro high-speed railway on cement, brick, mechanical equipment, etc.
Principle of use
The expansion bolt is composed of screw and expansion pipe. The tail of screw is conical, and the inner diameter of cone is larger than that of expansion pipe. When the nut is tightened, the screw moves outward, and the conical part moves through the axial movement of the thread, and then the bolt type composite cable bracket forms a great positive pressure on the peripheral surface of the expansion pipe, and the angle of the cone is very small, so that the wall is damaged.
After heat treatment, the material of high strength expansion bolt with performance grade of 10.9 can reach the following requirements:
1. The nominal tensile strength of the expansion bolt is 1000MPa;
2. The yield ratio of expansion bolt material is 0.9;
3. The nominal yield strength of expansion bolt is 1000 × 0.9 = 900MPa
The meaning of performance grade of expansion bolt is a general standard. The performance of expansion bolt with the same performance grade is the same regardless of its material and origin. Only performance grade can be selected in design.
1. Drilling depth: the relevant information introduces the length of the expansion pipe, but I found that this depth is not enough in the specific construction, which may be related to the residual amount of debris in the hole, so you'd better be about 5mm deeper than the length of the expansion pipe. As long as you are greater than or equal to the length of the expansion pipe, the length of the expansion bolt left underground is equal to or less than the length of the expansion pipe.
2. Of course, the requirement of expansion bolts on the ground is that the harder the better, which also depends on the stress of the objects you need to fix. The strength of concrete (c13-15) is five times that of brick.
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