Abstract: To prevent a skid panel attached with wear resistance material of porcelain tiles or the like on its surface from warping in a longitudinal direction of laying the skid panel, a warp amount of a skid panel is predictively calculated from shrinkage strain, shrinkage force and upper and lower edge stresses of concrete, reverse camber is provided in the longitudinal direction of a mold of the skid panel with tensioning devices to nullify the final warp amount and concrete is fed to the mold to thereby fabricate the panel.

Abstract: A tunnel liner used for a shield tunneling method for a tunnel having a diameter of 1.5 to 7 m is fabricated by dividing a ring-shaped liner into a plurality of parts in the circumferential direction. The tunnel liner is required to be excellent in the dimensional accuracy with respect to the outer peripheral surface, to be tight, to be high in strength, and to be high in water tightness at the abutment between the adjacent liners. The tunnel liner is fabricated by a method of filling each arcuate enclosed hollow form with concrete, vibro-compacting concrete, molding the end surfaces of the tunnel liner, mounting the forms within a centrifugal molding drum, and tightly molding the outer peripheral surface of the forms by applying of a centrifugal force. According to this fabrication method, it is possible to effectively fabricate an excellent tunnel liner at a low cost.

Abstract: End plates are forcibly fixed on the longitudinal end surfaces of pillars such as foundation piles buried in the ground. The upper and lower end plates are butted, and are vertically held by a circumferential recessed groove on the inner surface of an inside ring which is divided in a plurality of parts in the circumferential direction. The inside ring is provided with a conical taper around the outside diameter surface. The conical taper is fastened by an outside ring externally fitted around the outside diameter surface of the inside ring, to join the pillars to each other. This joint structure is simple, and makes it possible to certainly join the pillars at the job site, without any welding. Moreover, there can be provided a tough joint structure against bending.