As the two kinds of bottom anchors available on the curtain wall "only two", the use of the rear expansion anchor and the self-expanding anchor is very similar, but there are certain differences in the specification usage and actual construction.

The method of use is quite different

Although the two are similar in mechanical properties, the difference in installation methods is very large. The installation method of the rear-expanded anchor bolt is complicated, and a separate reaming is required after the straight hole is drilled, and a special reaming drill bit is required for the reaming. Taking the M12 rear expansion anchor as an example, the reaming size reaches M24, and it is easier to hit the steel bar during installation. The installation method of the self-expanding anchor bolt is much simpler. On the one hand, it can save a lot of man-hours without separately reaming, on the other hand, it can be installed with a hammer, which is very labor-saving.

Different specifications in the sale

Above we talked about the problem that the rear-expanded anchor bolts are easy to touch the steel bars, which determines the limitations of the rear-expanded anchor bolts. This is also difficult to find the M20 and above specifications. The main reason for the bottom anchor. For a self-expanding anchor, since there is no separate reaming, the probability of hitting the rebar is relatively small. Therefore, the self-expanding anchor bolts can even reach the M20. However, when using large-size anchor bolts, try to understand the arrangement of the steel bars in the concrete to make a reasonable drilling plan.

Safety performance of both

Let's first discuss the different forms of self-expanding anchors that appear on the market. There are two main types, one is the self-expanding anchor bolt using a diamond cutter head, and the other is by adjusting the withdrawal height, slope and sleeve. The form of the barrel cut is from the reamed anchor. The first type of reaming effect is better than the second one, but it is expensive, and it is inevitable that the diamond head will be wasted once. The second type of anchor bolt with mechanical mechanism to complete the self-expanding bottom can only partially cut the concrete during installation, and the effect of reaming the former self-expanding bottom anchor is not achieved, but the construction is simple.

Although the construction of the bottom-expanding anchor bolt is cumbersome, the pre-reaming operation can make the anchor bolt expand even after installation, and the anchor bolt is not directly pulled out during the pull-out test. Small gauges such as M12's rear-expanded anchors and self-expanding anchors have very close tensile forces, but when the specifications are large, there are some differences in the mechanical properties of the two. However, the actual demand for anchors of M12 can account for more than 60%.

Rear expansion anchor

Difference with expansion anchor

The expansion anchor bolt is a kind of mechanical anchor bolt which forms a corresponding anchoring effect by the frictional force of the special mechanical structure and the concrete hole wall after being installed in position, and represents the anchor bolt with the Anka anchor bolt and the internal anchor bolt. The force effect of the expansion anchor bolt may vary greatly depending on the type of the anchor bolt, but it is difficult to reach the level of the rear expansion anchor bolt and the self-expanding bottom anchor bolt. It is better to understand the bottom anchor bolt and the expansion anchor bolt. The difference can be used to determine which anchor should be used during construction.

Some construction workers do not know the bottom anchor, and often use the expansion anchor as an expansion anchor, which is really dangerous. Before the construction, it is hoped that each manufacturer can provide the corresponding technical disclosure while selling the products, so that the construction personnel can understand the use of the products and the importance of the safety of the curtain wall engineering.

Taihao Warehouse Haojing Technology Co., Ltd. is located in No. 188, Luxin Road, Taicang City. It is a professional manufacturer of expansion screws.