Discussion on the principle of expansion bolt

First, Classification of anchor bolts Anchor bolts can be divided into fixed anchor bolts, movable anchor bolts, expanded anchor bolts and bonded anchor bolts. According to different shapes, it can be divided into L-shaped embedded bolt, 9-shaped embedded bolt, U-shaped embedded bolt, welding embedded bolt and bottom plate embedded bolt.

Second, the use of anchor bolts Fixed anchor bolts, also called short anchor bolts, are used to fix equipment without strong vibration and impact. Movable anchor bolt, also known as long anchor bolt, is a detachable anchor bolt, which is used to fix heavy mechanical equipment with strong vibration and impact. Anchor bolts are often used to fix stationary simple equipment or auxiliary equipment. The installation of anchor bolts should meet the following requirements: the distance from the center of bolts to the edge of foundation should not be less than 7 times the diameter of anchor bolts; The foundation strength of the bolts installed in the expansion anchorage shall not be less than 10MPa; There shall be no cracks in the drill hole, and attention shall be paid to prevent the drill bit from colliding with the steel bars and buried pipes in the foundation; The diameter and depth of the drilling hole should match the bolt of the expansion anchor. Bonding anchor bolt is a kind of anchor bolt commonly used in recent years, and its method and requirements are the same as those of expanding anchor bolt. But when bonding, pay attention to blow out the sundries in the hole, and do not get damp.

Thrid, Installation Methods of Anchor Bolts One-time embedding method: when pouring concrete, embed the anchor bolts. When the tower is controlled by overturning, the anchor bolt should be embedded once. Reserved hole method: the equipment is in place, the holes are cleaned, the anchor bolts are put into the holes, and after the equipment is positioned and aligned, the equipment is poured with non-shrinkage fine stone concrete which is one level higher than the original foundation, which is tamped and compacted. The distance from the center of anchor bolt to the edge of foundation should not be less than 2d(d is the diameter of anchor bolt), and should not be less than 15mm (when D ≤ 20, it should not be less than 10mm), and it should not be less than half the width of anchor plate plus 50mm. When the above requirements cannot be met, appropriate measures should be taken to strengthen it. The diameter of anchor bolts used in the structure should not be less than 20mm. When subjected to earthquake action, double nuts shall be used for fixing, or other effective measures shall be taken to prevent loosening, but the anchorage length of anchor bolts shall be longer than that of non-earthquake action.