Method for releasing tilt-up panel hoisting member

Abstract

Tilt-up building wall panels are fitted with inserts which are cast into the panel. The inserts have threaded openings into which a collapsible split bolt is inserted. The bolt is spread apart with a longitudinally inserted wedge to secure its exterior thread to the interior thread of the insert. The panel is erected into its upright position with suitable hoisting equipment engaging the protruding portion of the split bolt. The split bolt and the hoisting equipment are removed from the ground with a ground release device that is raised overhead with extensions attached to the release device. The release device includes a support structure which has a flat end face that is positioned against the side of the upright panel and a linearly reciprocating release plate mounted to the support structure. The operator positions the release device so that the release plate engages a portion of the wedge and he then retracts the plate by pulling a suitably connected actuating cable from the ground. The retraction of the release plate pulls with it the wedge so that the split bolt can be collapsed and axially withdrawn from the threaded opening. The release device includes means for biasing the release plate to its position proximate the flat end face of the support structure and it is further fitted with means preventing hardware withdrawn from the threaded opening from dropping to the ground.