Anchor Bolts play a vital role in the functioning of many structures.
From skyscrapers to innumerable bridges across the nation, anchor bolts have been a standard component in building construction for over a century. In addition to their use in residential construction projects, they are also used in commercial and industrial settings. Understanding the importance of anchor bolts is essential to the proper performance of a structure.
Anchor Bolts are used to attach non-structural and structural elements to concrete. The attaching may be made by various other elements: nuts, bolts, or steel plates. Non-moving parts can also be fastened using mechanical expansion. Anchor bolts transmit different kinds of load: both shear and tension forces. A bolt may experience momentary fatigue at a low speed, resulting in a weaker connection, whereas, a larger bolt may undergo momentary fatigue at higher speeds.
There are four basic types of bolts: bolt, wedge anchor bolts, dry pit bolts and slotted bolts. Each type exhibits a unique characteristic, which allows them to withstand different loads. In addition, some specific kinds of bolts exhibit extra properties that make them superior to others, as follows:
Fastener refers to the metallic part of an anchor that connects two or more parts of a structure together. Metal materials used for fastening fasteners include rivets, stainless steel rods, screws, pins, and nuts. Although most fasteners are manufactured out of metal, there are also those made from plastic and other non-metal materials. Examples of plastic fasteners include acrylic rod inserts, hot-dip galvanized steel fasteners, and cold-dip steel fasteners. Examples of other non-metal fasteners include aluminum and brass fasteners.
Cast-in-place bolts, on the other hand, are similar to wedged anchors but the former are installed with a wooden frame. Cast-in-place bolts are often used for applications where the strength of the fastener is limited, and the connection cannot be compromised by any external force. Cast-in-place bolts have the advantage of providing a very strong holding power, even for extremely heavy bolts. However, they are not immune to rusting. Rusted bolts can be replaced easily, especially when corroded or brittle bolts are exposed.
Rationally speaking, all the above examples (cast-in-place bolts and galvanized steel bolts) exemplify the basic difference between one end of a bolt and the other. A bolt is a closed loop that only has one continuous path through the hole, whereas an anchor is open; hence, it comprises two loops and an outer surface. Bolts are available in numerous shapes, sizes, diameters and thread types. Two most common varieties are threaded and hexagonal. The inner diameter of the threads depends on the bolt diameter and the number of threads per inch. Hexagonal threads are smaller and narrower than typical rectangular threads.