Foot Bolt Tensile bearing capacity
The tensile strength of the anchor bolts is the tensile strength of the round steel itself, and the size is equal to the cross-sectional area multiplied by the tensile strength design value (140MPa) is the design of the tensile capacity. The anchor bolts are generally made of Q235 steel.
Has not seen the situation with the rebar, but if the force required, then also not a bad idea. Rebar (Q345) strength, do nuts do not have a round button easy. For the light round anchor bolts, the depth is generally 25 times the diameter of it, and then do a 120mm long 90 degrees hook. If the bolt diameter is very large (such as 45mm) buried depth is too deep, you can weld the end of the bolt, that is, to do a big head on it (but also have some requirements). Buried depth and hook are to ensure that the friction between the bolt and the foundation, and will not make the bolt out of the destruction. Therefore, the tensile strength of the anchor bolts is the tensile strength of the steel itself, and the size is equal to the cross-sectional area multiplied by the tensile strength design (140MPa) is designed to allow tensile bearing capacity. If the anchor bolts are not installed, there is a deviation, it will directly affect the quality of the entire project. So that the deviation of the bolt is a very dangerous thing, so be sure to check and correct, especially the high degree of automation linkage equipment. When the deviation occurs, should be based on the actual situation of the equipment for processing, using different treatment methods, the general common bias and processing methods can be divided into the following four:
1. Center bolts center deviation: anchor bolts in the diameter of 30mm below the center line within 30mm offset, you can first use oxygen acetylene bolts roasted, and then use the sledgehammer bolt (or jack jacking) After correction, use steel plate welding reinforcement, to prevent tightening the bolt when the recovery. If the bolt spacing is not right, you can use oxygen acetylene flame roasted after hammer with a sledge, in the middle of the steel plate reinforcement, in the subsequent grouting when it is dead. For larger bolts (greater than 30mm in diameter), the bolt should be cut off, with a piece of steel welded in the middle of the bolt, such as the bolt strength is not enough, can be welded on both sides of the bolt two reinforced steel plate, its length shall not Less than 3 to 4 times the diameter of the bolt.
2. Determination of the height of the anchor bolts: When the bolts are too high, the upper part of the bolts shall be cut off. In the set of threads, to prevent the drop of oil on the basis of concrete corrosion and affect the quality of the foundation. If the bolt is too low (less than its required height of 15mm), can not be used to elongate the heating method, you can dig a deep hole in the bolt around the pit at about 100mm from the bottom of the bolt to cut off the other welding a new bolt, Meet the requirements, and then use round steel reinforcement. Reinforcement of round steel is generally 4 to 5 times the diameter of the bolt.
3. Loosen the anchor bolts in the foundation: When the bolts are tightened, the bolts may be pulled out. At this time, the bolts should be adjusted to the original position, and the foundation around the bolts will be shoveled enough places, And then welded in the bolt on the vertical and horizontal two U-shaped steel, and finally the water will be clean and grouting in the pit, until the concrete solidified to the design strength and then tighten the nut.
4. Treatment of live foot bolt deviation: live foot bolt deviation of the treatment method, roughly the same with the method of dead feet bolts, but can pull out the anchor bolts to deal with. If the bolt is too long, you can cut a thread on the machine tool; if the bolt is too short, can be hot forging method elongation; such as the position does not match, with bending method correction.