Masonry Magazine August 1987 Page. 20
Headed Bolts
Square or hex-headed ASTM A 307 bolts are frequently used as anchor bolts due to their wide availability and relatively low cost (see Figure 1). Higher strength bolts, such as ASTM A 325 bolts, are available and can be used, but are more expensive. A washer placed against the bolt head is often used with the intention of increasing the bearing area and thus increasing the anchor strength. However, the actual strength increase obtained by adding a washer is small, if any, and under certain conditions (small edge distances), may actually decrease the tensile strength.
Bent Bar Anchors
Bent bar anchors, frequently used in masonry construction, are usually made in "J" or "L" shapes (see Fig. 2). Even though the "J" and "L" shapes are the more popular, a variety of shapes (see Fig. 3) is available since there currently is no standard governing the geometric properties of bent bar anchors. These anchors are usually made from ASTM A 36 bar stock and are shop-threaded.
Plate Anchors
Plate anchors are usually made by welding a square of circular steel plate perpendicular to the axis of a steel bar that is threaded on the opposite end (see Fig. 4). There are no standards governing the dimensions (length, width or diameter) of the plate. The American Institute of Steel Construction does limit the fillet weld size based on the plate thickness (see Table 1). Both the plate and bar are usually made from ASTM A 36 steel.
Through Bolts
As the name implies, through bolts extend completely through the thickness of the masonry and are composed of a threaded rod or bar with a bearing plate located on the surface opposite the attachment (see Fig. 5). In the early 1900's, through bolts were used in loadbearing masonry structures to tie floor and wall systems together. Often decorative cast bearing plates were used since through bolts were visible on the exterior masonry surfaces (see Fig. 6). Today, through bolts are primarily used in industrial construction where aesthetics are not a principal concern, or in retrofitting existing structures. Through bolt rods are usually made from ASTM A 307 threaded rod or threaded ASTM A 36 bar stock. Bearing plates are typically made from ASTM A 36 steel plate.