concrete butterfly anchors

Indented foundation bolts, also known as anchor bolts, are designed with a unique feature - an indentation or groove on their surface. This indentation serves a dual purpose. Firstly, it increases the surface area in contact with the concrete, thereby enhancing the bond strength between the bolt and the foundation. Secondly, during the tightening process, the indentation acts as a stress concentrator, causing the concrete around it to fracture, creating a mechanical interlock. This mechanism significantly improves the load-bearing capacity and resistance to shear forces.

...

Chemical anchor bolts are specialized fasteners that utilize a two-part adhesive system to bond with the concrete substrate. Unlike traditional mechanical anchors that rely purely on physical expansion or friction to secure themselves within the concrete, chemical anchors use a resin or adhesive, which is mixed with a hardener, to create a strong bond. This resin is typically injected into pre-drilled holes in the concrete before the anchor bolt is inserted. As the resin cures, it forms a very strong adhesive bond with both the bolt and the concrete, leading to excellent load-bearing capabilities.


...