It would be difficult to attach almost anything to concrete if it were not for concrete anchor bolts. Installing these bolts has become easier due to advancements made in materials and anchor bolt design. However, it is important to remember that these bolts will only be as strong as the concrete in which they are placed. Concrete anchors perform their job in one of two ways; by applying pressure through expansion against the whole wall or through friction on the sides of the hole in which they are placed.
The right bolt can be chosen according to the load it will be required to hold. Shear loads and tensile loads are two basic load types that help to determine the correct bolt choice. A shear load applies force against a bolt in a parallel manner. For example, a wooden framed wall fastened to a concrete floor. A tensile load applies force against a bolt in a perpendicular manner. For example, a steel water pipe suspended from a concrete ceiling.
Once the appropriate concrete anchor bolt is selected, it is time to decide where to place them. Never place a bolt too close to the edge of concrete. Doing so will likely weaken and eventually break the concrete. To determine a safe distance from a concrete edge, multiple the diameter of bolt by five. It is also important to maintain a safe distance from other bolts. To determine the correct distance from other bolts multiple the diameter of the bolt by ten.
Installing concrete anchor bolts requires the use of a hammer drill, concrete drill bits matching the diameter of the bolt, and the appropriate wrench or socket set. Always use proper ear and eye protection and follow the specific instructions provided by the manufacturer of the materials and products being used.
