CONICAL SEISMIC ANCHOR AND DRILL BIT FOR USE WITH UNREINFORCED MASONRY STRUCTURES

摘要

CONICAL SEISMIC ANCHOR AND DRILL BIT FOR USE WITH UNREINFORCED MASONRY STRUCTURES A process for attaching a seismic anchor to a wall of an unreinforced masonry structure includes the steps of drilling a generally frusto-conical cavity into the wall, and securing a seismic anchor into the cavity having a frusto-conical plug whose dimensions match at least a portion of the wall cavity. A drill bit utilized to form the wall cavity is adapted to be rotatably driven by a drill motor and includes a generally frusto-conical cutting blade support, a shank extending rearwardly from the blade support to be clamped within the chuck of the drill motor, and a drill stop positioned over the shank and secured to the rear end of the blade support. The blade support includes a plurality of radially extending planar exterior surfaces which span the length of the blade support and provide support surfaces for a plurality of cutting blade inserts. A removable pilot drill bit is fixed to a front end of the blade support for cutting a pilot hole into which the blade support is worked. The seismic anchor includes an attachment support rod having a first end and an adjacent portion thereof threaded for receiving a nut. The plug is preferably formed of a concrete material cast in place over the support rod, having sufficient strength that shear and tension forces applied the support rod will cause a failure of the wall relative to the anchor before any failure of the plug relative to the support rod.