Abstract: A gantry is constrained to move around the walls of a cylindrical, concrete tank. A rotating, high pressure water spray nozzle is mounted to a moveable platform on the gantry and connected to a source of water at a pressure of over 20,000 psi. The distance between the nozzle and an opposing surface of the wall of the tank is selected so the nozzle can remove the surface of the concrete and produce a selected surface roughness. The platform is moved vertically, with the gantry moving around the tank, so the surface of the concrete is systematically removed and roughened. A shotcrete or gunnite sprayer is then mounted to the platform, and the roughened surface sprayed with shotcrete or gunnite which sticks to the roughened surface. A tensioning head is then mounted to the platform, and wires or cables are tensioned as they are wrapped around the walls.

Abstract: The rigid, generally planar, rectangular first sheet, at least one rigid sheet spacer mounted along, so as to protrude from, a first long edge of the first sheet, and a generally “U”-shaped first channel formed along a second long edge of the first sheet, where the second long edge is opposite the first long edge. The first channel opens towards the sheet spacer so as to define a cavity therebetween and along the length of the first sheet. The first channel is sized so as to fit over, as an end cap on, an exposed long edge of a door frame member such as a door jamb or a center frame member of for example a double width door when so fitted, a distal side wall of the first channel, distal from the first sheet, is mated to a first side of the exposed long edge of the door frame member. The first channel includes a channel spacer protruding into the cavity.

Abstract: A rectangular ceiling tile to be supported in an exposed type suspended grid system of perpendicularly crossing girders of inverted T-profile. The tile comprises a core of fiber material with two opposite first edges forming each a stepped groove, and two opposite second edges forming each a recess for receiving the girders therein. At least one metal or plastic element is inserted into the fiber material of the core in a transverse edge surface thereof and forms a protruding ridge extending transversely of the tile.