Anchor bolts, this kind of bolts are used to fix the ma […]
Anchor bolts, this kind of bolts are used to fix the machine on the ground. Because of its strong stability, we often see it used in bridges, mines, railways, highways, power companies, cement plants, automobiles, motorcycles, tower cranes, boiler steel structures, large-span steel structures, and large buildings, etc. . The role of anchor bolts is obvious, it is very important, let's understand the specific situation of anchor bolts.
First, let's understand the material of anchor bolts. Generally, Q235 and Q345 are used to make anchor bolts. Q345 (that is, threaded steel) has a relatively high strength, so the thread of the nut is not as simple as using a round shape. If it is to embed smooth round anchor bolts, the depth of embedment is about 25 times the diameter of the bolt. Of course, a hook with a 90-degree angle and a length of about 12 cm is required. It is possible that the diameter of the bolt is too large (for example, 45mm) so that the depth of embedment will be relatively large. At this time, a square plate needs to be welded on the top of the anchor bolt (that is, a large head, but this must also meet the regulations. of).
Why do installation anchor screws need to have embedded depth and angle requirements? All this is to ensure the friction between the anchor bolts and the foundation and prevent the anchor bolts from being pulled out and damaged. What about the tensile strength of the anchor bolts that the engineers usually talk about? In fact, the tensile capacity of the anchor bolts is the tensile capacity of the round steel itself, so the tensile capacity of the anchor bolts is equal to the cross-sectional area multiplied by the design value of tensile strength (140MPa), and the calculated value is what is allowed in the design Tensile capacity. The tensile strength has two values, one is the allowable tensile strength and the other is the ultimate tensile strength. Because our engineering design needs to be controlled within a safe range, we allow the value of the tensile force to be less than the ultimate tensile force value. (Ultimate tensile strength = effective area of thread * tensile strength of steel, of which Q235 tensile strength is 235MPa)