Anchor bolts are actually the most common type of bolts in our lives, especially advertising signs on main roads, anchor bolts exist in the infrastructure of high-rise buildings, and even some simple factories. Most of the machines for fixing equipment also need anchor bolts. And the anchor bolts are also divided into more detailed ones, and the anchor bolts used by different equipment are also different.
Anchor bolts are generally divided into: fixed anchor bolts, movable anchor bolts, expansion anchor anchor bolts and adhesive anchor bolts. According to different shapes, it is divided into: L-shaped embedded bolts, 9-shaped embedded bolts, U-shaped embedded bolts, welded embedded bolts, and bottom plate embedded bolts.
Anchor bolts are buried in the ground or foundation, which is a tool that connects the foundation and machinery. Generally, Q235 steel is used, which is round. Rebar (Q345) has high strength, and it is not easy to make the thread of the nut. For smooth round anchor bolts, the buried depth is generally 25 times the diameter, and then a 90-degree hook with a length of about 120mm is made. If the bolt diameter is very large (such as 45mm) and the buried depth is too deep, you can weld a square plate at the end of the bolt, that is, just make a large head (but there are certain requirements). The buried depth and the hook are to ensure the friction between the bolt and the foundation, so that the bolt will not be pulled out and damaged. The anchor bolts have the function of fixing equipment without strong vibration and impact.
The tensile capacity of the anchor bolt is the tensile capacity of the round steel itself, and the size is equal to the cross-sectional area multiplied by the allowable stress value (Q235B: 140MPa, 16Mn or Q345: 170MPA) is the allowable tensile bearing capacity during design. It is to multiply its cross-sectional area (which should be the effective area of the thread at this time) by the yield strength of the steel (the Q235 yield strength is 235MPa). Since the design value is biased towards safety, the allowable stress during design is less than the yield strength.