JPH0514971Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to the improvement of the buckling prevention structure of prestressed steel used in the compression section of prestressed concrete members.

[Prior art]

Conventionally, buckling prevention structures for preventing the prestressed steel inserted into prestressed concrete members from buckling when compressed are disclosed in Japanese Utility Model Publication No. 58-53877 and Japanese Utility Model Publication No. 58-58.
As disclosed in Publication No. 53878, a large number of deformed parts with elliptical cross sections are formed in the sheath into which the PC steel material is inserted, and the long axis direction of the ellipse of adjacent deformed parts is changed around the sheath center line. A structure with a similar structure is known.

[Problem that the invention attempts to solve]

However, it is actually very difficult to manufacture a sheath with a deformed part as described above.
Furthermore, the machining accuracy is extremely poor, so that the purpose of preventing buckling cannot be sufficiently achieved, and the manufacturing cost is higher than that of a sheath having a circular cross section.

Furthermore, in the case of the conventional sheath, it is impossible to prevent buckling by housing a plurality of prestressing steel materials in one sheath due to its processing accuracy.

[Purpose of the invention, structure]

This idea is a PC that can advantageously solve the above-mentioned problems.
The purpose of this invention is to provide a structure to prevent buckling of a prestressed steel material in a compressed part of a member. , the PC steel material buckling prevention structure of the PC member compression part is characterized in that the sheath 3 restrains deformation in the direction perpendicular to the axis and is inserted.

〔Example〕

Next, this invention will be explained in detail using illustrated examples.

1 and 2 show a first embodiment of this invention, in which a sheath 3 with a rectangular cross section is buried in a prestressed concrete member 2, and a PC steel bar with a circular cross section is inserted into the sheath 3. become PC
The steel material 1 is inserted so that deformation in the direction perpendicular to the axis is restrained by the sheath 3, that is, so that no large gap is created between the prestressing steel material 1 and the sheath 3, and furthermore, the sheath 3 and the prestressing steel material 1 are A room-temperature hardening grout material 4 is injected and filled into the gap between them.

3 and 4 show a second embodiment of this invention, in which a sheath 3 with a rectangular cross section is buried in a prestressed concrete member 2, and a PC steel wire with a circular cross section is inserted into the sheath 3. A large number of prestressing steel materials 1 are inserted in a state in which they are lined up in the vertical and horizontal directions, and deformation in the direction perpendicular to the axis is restrained by the sheath 3, and between the sheath 3 and the prestressing steel materials 1. A hardenable grout material 4 is injected and filled into the voids between the PC steel materials 1 and the voids between the PC steel materials 1.

FIG. 5 shows a third embodiment of this invention, in which a large number of PC steel members 1 made of stranded PC steel wires each having seven strands are arranged vertically and horizontally in a sheath 3. Although the sheath 3 is inserted in such a manner that deformation in the direction perpendicular to the axis is restrained, the other configurations are the same as in the second embodiment.

When implementing this idea, the cross-sectional shape of the sheath 3 may be either square or rectangular. Further, the sheath 3 is made of steel, plastic, or the like. Further, as the room temperature hardening grout material, for example, cement milk or mortar is used.

[Effect of idea]

According to this invention, when the prestressing steel material 1 is compressed, the deformation of the prestressing steel material 1 in the direction perpendicular to its axis is restrained by the duct formed by the sheath 3 having a rectangular cross section, so buckling of the prestressing steel material 1 is ensured. In addition, since the sheath 3 has a rectangular cross section, it can be easily manufactured with high precision at low cost. Effects such as being able to use a large number of prestressed steel materials by fitting them into the sheath 3 in an orderly manner can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view showing a PC steel material buckling prevention structure of a PC member compression part according to a first embodiment of this invention;
FIG. 2 is a longitudinal sectional side view thereof. FIG. 3 is a longitudinal sectional front view showing a PC steel material buckling prevention structure of a PC member compression section according to a second embodiment of this invention, and FIG. 4 is a longitudinal sectional side view thereof. FIG. 5 is a longitudinal sectional front view showing a PC steel material buckling prevention structure of a PC member compression section according to a third embodiment of this invention. In the figure, 1 is a prestressed steel material, 2 is a prestressed concrete member, 3 is a sheath, and 4 is a room temperature hardening grout material.

Claims (1)

[Scope of utility model registration request] A PC member compression section characterized in that a PC steel material 1 is inserted into a sheath 3 with a rectangular cross section buried in a prestressed concrete member 2, with deformation in the direction perpendicular to the axis being restrained by the sheath 3.
Steel buckling prevention structure.