Abstract: A steel rod of the type having a generally rounded core and two or more spaced series of parallel ribs projecting therefrom, so constructed that the ribs act as threads to attach the rod to an anchoring or connecting device which has matching internal threads, is provided which in addition to the rib structure has a longitudinal groove in at least one of the regions between the adjacent ends of two of the series of ribs. The longitudinal groove or grooves provides a canal which permits the cavities between the rod and an enveloping anchoring or connecting means to be filled with cement or similar material which will protect the internal surfaces against corrosion.

Abstract: Steel rods are formed, by hot rolling, with at least three (preferably four) series of ribs extending along the length thereof. The ribs are all formed to extend along a spiral line along the surface of the rods and are so constructed that any cross-cut through the rod must pass through at least one rib. Each of the ribs has end portions which gradually blend into the core of the rod, which core is substantially circular in cross-section. The outer surfaces of the end portions are substantially straight and tangential to the core. Thus, when viewed from the end or in cross-section, the rod has the appearance of a polygon. The polygonal shape of the rod prevents it from rotating after embedding it in concrete when tension is applied to an end thereof. The spiral arrangement permits tension to be applied to the rods by means of screw nuts, etc.

Abstract: A reinforcing member, especially suitable for anchoring to the earth or to a rock, is made up of two or more separate rods which are shaped to fit together to provide a unit with a generally round cross-section and with spiral ribs on the outer surfaces of the unit. Each of the separate rods which make up the member or unit, have two flat surfaces which are radial with respect to the circular unit and which interfit in surface to surface contact with corresponding surfaces of the complementary rods, except that recesses are provided at the interior ends of the radial surfaces which together form a central conduit in the assembled unit. The central conduit may be employed, per se, as an injection conduit for mortar to fix the end of the rod in an anchoring rock for example, or it may act as venting means to assure that air is not retained in hole boring in which the unit is to be secured by mortar or cement. A tubular pipe may be included in the hollow center to facilitate injection or venting.