Provided is a novel metallic coarse aggregate for concrete which can be used as a coarse aggregate which is one of the essential constituents of concrete, can further improve the compressive strength and tensile strength of concrete, is less likely to be sedimented in fresh concrete, and has good productivity at a low cost. The metallic coarse aggregate for concrete includes a coarse aggregate body including a spherical cap portion bonded body having two hollow spherical cap portions and an annular portion protruding from a surface of the spherical cap portion bonded body so as to surround an outer periphery of the spherical cap portion bonded body, the annular portion having a shape in which a corner of a rectangular shape is bent upward or downward.

A method for producing a partially contoured, fiber-reinforced plastic profile includes providing a plurality of first reinforcing fibers. The first reinforcing fibers are combined to produce a uni-, bi-, or tridirectional fiber bundle. The fiber bundle is impregnated with a first plastic matrix. The impregnated fiber bundle is supplied to a unit for at least partial shaping or for at least partial shaping and at least partial curing of the first plastic matrix to produce a fiber-reinforced plastic base element. Second reinforcing fibers are provided for at least partial application to the fiber-reinforced plastic base element. The fiber-reinforced plastic base element is provided with the second reinforcing fibers for at least partial fiber-reinforced profiling and/or shaping to produce an at least partially contoured, fiber-reinforced plastic strand and the at least partially contoured, fiber-reinforced plastic strand is cut to produce an at least partially contoured, fiber-reinforced plastic profile.

A method for producing a partially contoured, fiber-reinforced plastic profile includes providing a plurality of first reinforcing fibers. The first reinforcing fibers are combined to produce a uni-, bi-, or tridirectional fiber bundle. The fiber bundle is impregnated with a first plastic matrix. The impregnated fiber bundle is supplied to a unit for at least partial shaping or for at least partial shaping and at least partial curing of the first plastic matrix to produce a fiber-reinforced plastic base element. Second reinforcing fibers are provided for at least partial application to the fiber-reinforced plastic base element. The fiber-reinforced plastic base element is provided with the second reinforcing fibers for at least partial fiber-reinforced profiling and/or shaping to produce an at least partially contoured, fiber-reinforced plastic strand and the at least partially contoured, fiber-reinforced plastic strand is cut to produce an at least partially contoured, fiber-reinforced plastic profile.

A V-shaped tie hoop assembly enhances field construction performance by integrally forming a plurality of V-shaped tie hoops after constituting the plurality of V-shaped tie hoops in a bundle form, maintains intervals, and enhances reinforcement performance. The V-shaped tie hoop assembly can includes: a plurality of V-shaped tie hoops, each of which has a bending part at the center thereof and anchor parts extending to opposite sides of the bending part, and disposed at different heights at an interval; and a vertical support bar connecting all of the V-shaped tie hoops to integrally couple the V-shaped tie hoops.

A stud-weldable rebar and a method for making the rebar are disclosed. The rebar has a steel body with a weld end and a diameter that is substantially uniform along a length of the body. A tip portion at the weld end includes a hardened zone and a base portion is formed of the remaining steel body. The hardened zone has a hardness that is about 1.5-3.0 times greater than a hardness of the base portion. Induction hardening is used to form the hardened zone.

A pre-stressed concrete structure comprises a steel wire or a steel strand. The steel wire or steel strand has been pre-tensioned before curing of the concrete or grout. The steel wire or steel strand is provided with a zinc coating. The zinc coating has a weight ranging between 70 g/m.sup.2 and 950 g/m.sup.2. The steel wire or steel strand has an outer surface that is provided with indentions to provide mechanical anchorage points in the concrete structure. The steel wire or steel strand is further provided with a passivation layer in the form of a metal oxide layer.

A pre-stressed concrete structure comprises a steel wire or a steel strand. The steel wire or steel strand has been pre-tensioned before curing of the concrete or grout. The steel wire or steel strand is provided with a zinc coating. The zinc coating has a weight ranging between 70 g/m.sup.2 and 950 g/m.sup.2. The steel wire or steel strand has an outer surface that is provided with indentions to provide mechanical anchorage points in the concrete structure. The steel wire or steel strand is further provided with a passivation layer in the form of a metal oxide layer.

A pre-stressed concrete structure comprises a steel wire or a steel strand. The steel wire or steel strand has been pre-tensioned before curing of the concrete or grout. The steel wire or steel strand is provided with a zinc coating. The zinc coating has a weight ranging between 70 g/m.sup.2 and 950 g/m.sup.2. The steel wire or steel strand has an outer surface that is provided with indentions to provide mechanical anchorage points in the concrete structure. The steel wire or steel strand is further provided with a passivation layer in the form of a metal oxide layer.

A pre-stressed concrete structure comprises a steel wire or a steel strand. The steel wire or steel strand has been pre-tensioned before curing of the concrete or grout. The steel wire or steel strand is provided with a zinc coating. The zinc coating has a weight ranging between 70 g/m.sup.2 and 950 g/m.sup.2. The steel wire or steel strand has an outer surface that is provided with indentions to provide mechanical anchorage points in the concrete structure. The steel wire or steel strand is further provided with a passivation layer in the form of a metal oxide layer.

The joint has a prefabricated-reinforced-concrete column, a reinforced-concrete foundation, a column anchoring longitudinal bar, a grouting sleeve and a foundation anchoring steel bar. The foundation anchoring steel bar and the column anchoring longitudinal bar are connected by a seam filling material filling the grouting sleeve. A splicing seam between the reinforced-concrete foundation and the prefabricated-reinforced-concrete column is filled with the seam filling material. The foundation anchoring steel bar includes a vertical portion and a horizontal portion. The vertical portion includes an upper-portion anchoring section protruding out of an upper surface of the reinforced-concrete foundation, a middle-portion non-adhesive section buried within the foundation and a lower-portion anchoring section. An exterior of the middle-portion non-adhesive section is provided with an isolating sheath for isolating the middle-portion non-adhesive section and the concrete adhesion.