This is a very common use of all thread rod. When anchor bolts are needed in pre-existing concrete, a hole is drilled into the concrete, then the hole is filled with epoxy and a piece of all thread rod is placed in the hole. Once the epoxy bonds with the threads on the all thread rod, it provides pullout resistance, allowing the rod to act as an anchor bolt.
All thread rods are also commonly used as extenders in the field. No one is perfect and mistakes happen when foundations are poured, probably more often than anyone would like to admit. Sometimes anchor bolts are set too low, and when this occurs, the easiest fix is to extend the anchor bolt with a coupling nut and piece of threaded rod. This allows the contractor to extend the threads of the existing anchor bolt and properly tighten the nut.
All thread rods are often used as anchor bolts. They are embedded in concrete and provide pull out resistance with their fully threaded bodies, along with the help of a nut, or nut and plate combination. All thread rod anchor bolts are commonly specified using the anchor bolt specification F1554 in Grades 36, 55 and 105. All thread rods are commonly substituted for thread-each-end anchor rods in circumstances when the anchor bolts are needed quickly. Because all thread rod is commonly available off the shelf, or in a quick turn-around time, it is often substituted, with the Engineer of Record’s approval, for a faster lead time and a cheaper cost.
Pipe Flange Bolts
All thread rod is also commonly used to bolt pipe flanges together. This is especially true for A193 Grade B7 all thread rod which is designed for high temperature, high pressure applications. The short all thread rod pieces bolt the pipe flanges together with nuts on each end of the rod. Another common grade of all thread rod used in this application is ASTM A307 Grade B.
Double Arming Bolts
All thread rods are also used in the pole line industry as double arming bolts. This bolt type is used to secure one cross arm on each side of a wooden utility pole. The advantage to using fully threaded rods in this application is to allow for maximum adjustment for the cross arms on the poles which can vary depending on a number of factors. Double arming bolts are typically sold with four square nuts, two assembled on each end, along with an added semi-cone point on each end to facilitate ease of installation in the field.
All thread rods are used from time to time in virtually any construction fastening application. They are used with a nut on each end and for fastening wood, steel, and other types of construction materials. They are often substituted for a hex bolt or other type of bolt with a forged head, however, such substitutions should only be made with the blessing of the Engineer of Record on the project.