Abstract: A structure enables free and reasonable designing of a cross section of an end of a steel beam in accordance with bending stress and a housed state of a PC steel, thereby providing an economic and reasonable building as a whole. A beam end block includes end plates and an anchor plate. The end plates are fixed at an end surface of an H-section steel in a direction substantially perpendicular to the longitudinal direction of the beam. The anchor plate is fixed to the H-section steel separately from the end plates, on a side opposite to a column, in a direction substantially perpendicular to the longitudinal direction of the beam. An end of the steel beam has an upper part and a lower part. The upper part protrudes toward the column more than the lower part and is mounted on a cogging.

Abstract: There is provided a method of introducing prestress into a beam-column joint of PC construction to make it into a triaxially compressed state, in which the beam-column joint is made into a triaxial compression state and reasonable prestress is introduced into cross section areas of the ends of the members forming the beam-column joint.

Abstract: There is provided a method of prestressing a beam-column joint with an appropriate ratio among the magnitudes of compression in the directions of X, Y, and Z axes. The method introduces prestress in a beam-column joint with a tensile introducing force generated by tensionally anchoring prestressing tendons that are arranged in PC beams extending along two horizontal directions (or X axis and Y axis) and PC columns extending along the vertical direction (or Z axis) and passed through the beam-column joint to bring the beam-column joint in triaxial compression, the prestress being introduced such that a diagonal tensile force T generated by an input shear force due to a seismic load of an extremely great earthquake that may occur very rarely will be cancelled completely or partially so as not to allow diagonal cracks to occur. The ratio of the prestresses introduced in the directions of the respective axes satisfies the following equation (1): ?x:?y:?z=1:1:0.3?0.

Abstract: A method is provided for jointing a concrete column and an iron beam. A structure joint portion is provided between a column-beam junction and an end of the iron beam, which is mourned on a coning provided to the column. Prestressing tendons are arranged in plural rows to horizontally penetrate the column-beam junction, Tension-introduction forces are applied to the prestressing tendons to tensionally anchor an anchor plate, and thereby to integrally joint the column and the beam.

Abstract: In an earthquake resisting design method of a PC construction, a column and a beam, which are high-strength precast prestress concrete members, are joined by binding juncture with a prestressing tendon. A grout is filled and bonded. A first stage linear resilient design is employed, where all construction members are not damaged, for earthquakes up to a predetermined earthquake load design value. A second stage linear resilient design is employed, where earthquake energy is absorbed by breakage of the bond of the grout, and principal construction members are not damaged, for earthquakes exceeding the predetermined earthquake load design value. By employing a non-linear resilient design in which the first stage linear resilient design and the second stage linear resilient design are combined, an earthquake-resisting design level is significantly increased, and the construction can resist earthquakes exceeding a seismic intensity 6 upper.

Abstract: In a method for forming a rustproof film on a PC strand, the thickness of the resin film is set to 200±80 ?m, the pre-heating is performed within a temperature range from 60 to 150° C. to prevent an occurrence of a cob-webbing phenomenon as a result of melting of the synthetic resin powder coating material and the post-heating is performed within a range from 150 to 250° C. in order to uniformize the thickness of the coats adhered to the outer peripheral surfaces of the core wire and the surrounding wires, and the temperature of the pre-heating is set to be lower than the temperature of the post-heating, and the synthetic resin powder coating material including particles having diameters in a range from 0.1 to 250 ?m is used, and the line speed in the series of steps is set to 5 to 10 m/min.

Abstract: A double rustproof PC strand has superior durability and semi-permanent rustproof performance. A core wire and surrounding wires are formed of wires subjected to a wire drawing treatment and a plating treatment to be formed with a plated layer. A rustproof treatment is applied by forming a synthetic resin coat on an outer peripheral surface thereof. In order to uniformize and regulate the twisting pitch, the core wire and the surrounding wires are adjusted under the conditions of: (A) Diameter of CORE: 4.42±0.05 mm, Diameter of Surrounding wire: 4.25±0.05 mm, (B) Diameter of CORE: 5.22±0.05 mm, Diameter of Surrounding wire: 5.06±0.05 mm, or (C) Diameter of CORE: 5.40±0.05 mm, Diameter of Surrounding wire: 5.25±0.05 mm, and then twisted, and the tensile strength is 1850 N/mm2 or higher.

Abstract: In order to provide a double rustproof PC strand with superior durability and semi-permanent rustproof performance, a core wire and surrounding wires are formed of wires subjected to a wire drawing treatment and a plating treatment and formed with a plated layer, and a rustproof treatment is applied by forming a synthetic resin coat on an outer peripheral surface thereof. In order to uniformize and regulate the twisting pitch, the core wire and the surrounding wires are adjusted under the conditions of (A) Diameter of CORE: 4.42±0.05 mm, Diameter of Surrounding wire: 4.25±0.05 mm, (B) Diameter of CORE: 5.22±0.05 mm, Diameter of Surrounding wire: 5.06±0.05 mm, or (C) Diameter of CORE: 5.40±0.05 mm, Diameter of Surrounding wire: 5.25±0.05 mm, and then twisted, and the tensile strength is 1850 N/mm2 or higher.

Abstract: A PC strand is untwisted to separate surrounding wires from a core wire, a synthetic resin powdered coating material is uniformly adhered by being applied and heated over the outer periphery of the core wire and surrounding wires in this untwisted state, the product is cooled to form a resin film, and then the surrounding wires are twisted back to the original state with respect to the core wire. Pre-heating is performed before the coating step and post-heating is performed after the coating step, the pre-heating temperature is set 30 to 130° C. higher than the post-heating temperature, a synthetic resin powdered coating material having an average grain size of 40 to 50 ?m is used, and the process line speed is 5 to 10 m/min.

Abstract: To improve tensile strength without impairing flexibility and adhesion to concrete, and to form a thick coating in a surface layer part for preventing a basis material from being exposed by damage to the coating, a method of forming double coatings on a prestressing strand includes a primary painting process after a pre-treatment process, in which a resin coating is formed only at the surface layer, a secondary painting process in which respectively individual state resin coating is formed on an outer peripheral face of each of the core wire and surrounding wires under a loosened and separated state, thereby forming a double coating for each surrounding wire, and a finishing process of tightening and retwisting the surrounding wires about the core wire to an original state. The obtained prestressing strand has the double coating portions only at the surface layer and sufficient flexibility and adhesion to concrete.

Abstract: To improve tensile strength without impairing flexibility and adhesion to concrete, and to form a thick coating in a surface layer part for preventing a basis material from being exposed by damage to the coating, a method of forming double coatings on a prestressing strand includes a primary painting process after a pre-treatment process, in which a resin coating is formed only at the surface layer, a secondary painting process in which respectively individual state resin coating is formed on an outer peripheral face of each of the core wire and surrounding wires under a loosened and separated state, thereby forming a double coating for each surrounding wire, and a finishing process of tightening and retwisting the surrounding wires about the core wire to an original state. The obtained prestressing strand has the double coating portions only at the surface layer and sufficient flexibility and adhesion to concrete.

Abstract: Disclosed is a method of forming corrosion protection coatings on prestressing strands. It comprises the steps of untwisting sequential lengths of a prestressing strand; keeping the surrounding steel wires apart from the core steel wire to coat these steel wires with a synthetic resin; and twisting the coated steel wires to provide a prestressing strand of the original shape, thus permitting the separate coating of each steel wire, leaving, on the prestressing strand surface, the helical dent as deep and wide as the noncoated prestressing strand to assure the bond of the twisted wire to the surrounding concrete as firm as the noncoated prestressing strand. Also, an apparatus for carrying out such coating method is disclosed.