JP2007107217A - Structure of precast concrete plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plate-like precast concrete plate of introducing prestress. <P>SOLUTION: This structure of the precast concrete plate 10 has a concrete plate 12, a plurality of strips of truss reinforcements 14 mutually implanted at an interval in the plate, that is, a plurality of strips of truss reinforcements composed of mutually parallel two strips of lower end reinforcements 18, one strip of top reinforcement 20 positioned above these reinforcements and a lattice reinforcement 22 arranged between the respective lower end reinforcements and the top reinforcement and joined to these reinforcements, and a PC steel material 16 arranged in the vicinity of these reinforcements between both lower end reinforcements of the respective truss reinforcements or above the lower end reinforcements and extending in the plate along the lower end reinforcements. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a precast concrete board in which prestress is introduced.

  Conventionally, a precast concrete board in which prestress is introduced is used for forming a floor slab in a concrete building.

As one of such precast concrete plates, a concrete plate-like main body having flat upper and lower surfaces opposed to each other, a plurality of parallel protrusions protruding from the upper surface of the main body, and a planted in the main body Rarely, there has been proposed a truss bar projecting upward from each protrusion and a PC steel material extending along each protrusion (see Patent Document 1 below).
Japanese Utility Model Publication No. 62-96411

  By the way, in the said conventional precast concrete board, the said PC steel materials are extended in the shape of a broken line, The said protrusion for receiving this is required.

  An object of the present invention is to provide a flat precast concrete board into which prestress is introduced.

  The present invention relates to a structure of a precast concrete plate, and is a concrete flat plate, a plurality of truss bars that are planted on the flat plate at a distance from each other, and two lower end bars parallel to each other and above them. A plurality of truss muscles, each of which is composed of a single top muscle located at the top of each other and a lattice muscle disposed between and joined to each bottom muscle and the top muscle; And a PC steel material disposed in the vicinity of these above the lower end bars and extending in the flat plate along the lower end bars. The precast concrete board may further include a mesh line that is embedded in the flat plate and is located below the lower end bar of the truss bar.

  In the present invention, the PC steel material arranged in the flat plate extends along the truss muscles implanted in the flat plate and is located between the upper and lower lower end bars of the truss muscles or in the vicinity above them. Therefore, the tensile stress that may be locally generated in the flat plate due to the arrangement of the PC steel materials arranged straight can be canceled out by the reinforcing action by the lower end bars of the truss bars.

  Since a high bending resistance can be obtained by the arrangement of the PC steel material in such a position, the arrangement of the main bars in the flat plate can be omitted, and the arrangement of the mesh bars as required can be sufficient. Moreover, since the truss reinforcement serves as a mark for the position of the PC steel material, it is possible to easily drill the flat plate avoiding the PC steel material.

  Referring to FIG. 1, a precast concrete board (hereinafter simply referred to as “PC board”) into which prestressing according to the present invention has been introduced is indicated generally by the reference numeral 10.

  The PC board 10 includes a flat plate 12 made of concrete, a plurality of truss bars 14 implanted in the flat plate 12, and a plurality of PC steel materials 16 arranged in the flat plate 12 and fixed thereto.

  The flat plate 12 has a rectangular planar shape having a length and a width.

  The plurality of truss bars 14 are arranged at intervals in the width direction of the flat plate 12.

  The truss bars 14 are arranged at substantially the center in the thickness direction of the flat plate 12 and extend in the flat plate 12 in the longitudinal direction. A single top muscle 20 extending in parallel and a lattice muscle 22 that is arranged between each lower reinforcement 18 and the top muscle 20 and is joined to these reinforcing bars and extends in a wave shape. Are exposed outside the flat plate 12.

  The number of PC steel materials 16 is the same as the number of truss bars 14, and each PC steel material 16 is disposed between the lower end bars 18 of each truss bar 14, preferably at an intermediate position between the lower end bars 18, and in the flat plate 12. It extends straight along the bottom line 18. The PC steel material 16 may be disposed in the vicinity of the lower end bars 18 and above the lower end bars.

  PC steel material 16 is being fixed to the both end surfaces in the length direction of flat plate 12 in the both ends, respectively. Due to the arrangement of the PC steel material 16, the flat plate 12 is prestressed in the longitudinal direction by the elastic restoring force of the PC steel material 16.

  In this way, by placing the PC steel material 16 between or in the vicinity of the lower end bars 18 of the truss bars, after the tensile force is exerted on the PC steel material 16 when manufacturing the flat plate 12 to which the stress is introduced, this is applied. The tensile stress that may be locally generated in the flat plate 12 when released is canceled by the lower end bars 18 of the truss bars fixed to the concrete constituting the flat plate 12.

  Moreover, high bending resistance can be given to the flat plate 12 by arrangement | positioning of such PC steel materials 16, For this reason, arrangement | positioning of the main reinforcement in the flat plate 12 is abbreviate | omitted, and mesh reinforcement is needed in the flat plate 12 as needed. 24 can be arranged. Further, since the truss bar 14 serves as a mark for the arrangement position of the PC steel material 16, it is possible to perform a free drilling operation on the flat plate 12 between the truss bars 14.

It is sectional drawing of the precast concrete board which concerns on this invention. It is a fragmentary perspective view of a truss muscle.

Explanation of symbols

10 Precast concrete plate 12 Flat plate 14 Truss 16 PC steel 18 Bottom bar 20 Top bar 22 Lattice bar 24 Mesh bar

Claims (2)

A concrete flat plate,
A plurality of truss bars that are implanted on the flat plate at a distance from each other and are parallel to each other, two bottom bars, one top bar located above them, each bottom bar, and each top bar A plurality of truss muscles composed of lattice muscles arranged between and joined to each other;
The structure of the precast concrete board including PC steel materials which are arrange | positioned in these vicinity between both the lower end bars of each truss reinforcement, or near these lower end bars, and extend in the said flat plate along this lower end reinforcement.   Furthermore, the structure of the precast concrete board of Claim 1 containing the mesh reinforcement located under the lower end reinforcement of the said truss reinforcement embed | buried in the said flat plate.

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