JP4373392B2 - PCa material - Google Patents

Description

  The present invention relates to the structure of a PCa (precast) member for a reinforced concrete column, and more particularly to a technique for connecting a column main reinforcing bar of another concrete member.

  When constructing a reinforced concrete column using a PCa member, it is necessary to connect the main bars between the PCa member and another concrete member (on-site concrete member or PCa member). As a connection structure between main bars, a structure using a splice sleeve has been proposed as described in Patent Document 1. Also, as disclosed in Patent Document 2, a sheath tube penetrating the PCa member is used, and a reinforcing bar lap joint is formed by overlapping reinforcing bars straddling between main bars. Furthermore, in Patent Document 3, a heterogeneous steel pipe into which the column main reinforcement of another concrete member connected to the PCa member is inserted, and the column main reinforcement of the PCa member is aligned with the column main reinforcement inserted into the irregular steel pipe. Has been proposed.

Japanese Examined Patent Publication No. 4-52815 Japanese Patent No. 2883898 JP 7-292860 A “Adhesive properties of rebar in sheath tube in precast member”, Annual Meeting of the Architectural Institute of Japan, C-2, September 2005, pp. 27-32.

  When a splice sleeve is used as described in Patent Document 1, the splice sleeve is relatively expensive and the diameter of the splice sleeve is large relative to the columnar main bars, so that the cover thickness around the splice sleeve is insufficient. easy. If an attempt is made to secure the cover thickness, the cover thickness becomes excessive at portions other than the periphery of the splice sleeve, resulting in waste.

  The same applies to the case where a modified steel pipe is used as described in Patent Document 3. Moreover, the thing of patent document 3 does not mutually arrange | position the column main reinforcement to which it connects. Therefore, it is necessary to prepare at least two types of PCa members in which the disposition positions of the atypical steel pipe and the column main bars are reversed, and a reinforced concrete column cannot be constructed with a single PCa member. In addition, Patent Document 3 states that when a thin sheath tube is used, the adhesion between the column reinforcement and the concrete is insufficient (paragraph 0007). However, in recent research, the sheath tube is used. Even so, it has been clarified that the adhesion between the column reinforcement and the concrete can be secured (Non-Patent Document 1).

  Therefore, the use of a sheath tube as in Patent Document 2 is advantageous in terms of cost and the difference in diameter from the column main bar is small, so the problem of insufficient cover thickness can be solved. However, the sheath tube penetrates the PCa member. In this case, the amount of the sheath tube and the grout material filled in the sheath tube is increased. Grout materials are generally expensive materials, which increases costs. Moreover, since the thing of patent document 2 is used as a reinforcing bar lap joint, the effort of arrangement | positioning of a reinforcing bar is involved in manufacture of a PCa member.

  The objective of this invention is providing the PCa member excellent in the workability of a reinforced concrete pillar at lower cost.

  According to the present invention, in a PCa member for a reinforced concrete column having a column main reinforcing bar, one end is opened in an end surface of the PCa member, and the other end is embedded in the PCa member so as to be located in the PCa member. A columnar main bar of a concrete member connected to the member is inserted and a sheath tube filled with a grout material is provided, and the columnar main bar of the PCa member includes a first linear portion located coaxially with the sheath tube; The second linear portion constituting the lap joint with the column main reinforcement of the concrete member, which is arranged along the sheath tube and inserted into the sheath tube, and the portion between the first and second linear portions are connected. There is provided a PCa member having a bent portion.

  In the PCa member of the present invention, by using the relatively inexpensive sheath tube, the cost can be reduced and the problem of insufficient cover thickness around the sheath tube can be solved. Since the total length of the sheath tube is sufficient for the length required for the lap joint (about 20 to 30 times the column main muscle diameter), the amount of the sheath tube and the grout material filled therein can be reduced. Moreover, by making the connection structure between the column main bars by the lap joint, it can be manufactured at a lower cost and more easily than the case of the reinforcing bar lap joint. Therefore, the cost of manufacturing the PCa member and constructing the reinforced concrete column can be reduced.

  Moreover, since the said 1st linear part of the said column main reinforcement and the said sheath pipe | tube are located coaxially, the said 1st linear part and the pillar principal reinforcement of the said concrete member are located coaxially. Therefore, it is possible to construct a reinforced concrete column with a single PCa member, and it is possible to construct a reinforced concrete column at a lower cost and more easily than when multiple types of PCa members are required.

  In the present invention, it is possible to adopt a configuration in which the second linear portion is disposed on the inner side of the PCa member with respect to the sheath tube. According to this structure, the filling property of the concrete to the clearance gap between column main bars can be improved.

  Further, in the present invention, it is possible to adopt a configuration in which an opening for opening the side surface of the PCa member and an injection passage for injecting the grout material into the sheath tube are formed. According to this structure, the injection | pouring operation | work of the grout material at the time of construction of a reinforced concrete pillar can be facilitated by forming the said injection | pouring channel | path.

  ADVANTAGE OF THE INVENTION According to this invention, the PCa member excellent in the construction property of a reinforced concrete pillar can be provided at lower cost.

  1A is a structural explanatory view of a PCa member A according to an embodiment of the present invention, FIG. 1B is a sectional view taken along line XX in FIG. 1A, and FIG. It is sectional drawing which follows the line YY of 1 (a). The PCa member A in the present embodiment is erected on the concrete member 100 that has been constructed and connected to the concrete member 100. The concrete member 100 is a column / beam joint member, and the column main reinforcement 101 protrudes upward from its upper end surface.

  In FIG. 1A, an unconstructed concrete member 200 constituting the upper floor is shown by a broken line above the PCa member A. The PCa member A constitutes a reinforced concrete column in a hierarchy between the concrete member 100 and the concrete member 200. Although not shown, it is of course possible to connect a plurality of PCa members A in succession to constitute a reinforced concrete column.

  The PCa member A includes a rectangular parallelepiped concrete portion 10 and a plurality of column main bars 20. The same number of sheath tubes 30 as the column main bars 20 are embedded in the concrete portion 10. The sheath tube 30 is a thin-walled cylindrical tube that is open at both ends, and is embedded so that the longitudinal direction thereof is directed in the vertical direction. The sheath tube 30 is preferably a spiral sheath tube in which spiral undulations are formed on the outer peripheral surface thereof in order to improve the adhesion of the concrete portion 10.

  The lower end of the sheath tube 30 opens to the lower end surface of the concrete part 10, and the upper end is embedded so as to be located in the concrete part 10. During construction of the reinforced concrete column, the column main reinforcement 101 is inserted into the sheath tube 30, and the column main reinforcement 101 and the column main reinforcement 20 constitute a lap joint as will be described later. It is sufficient that the sheath tube 30 has a total length that allows the lap joint to exhibit a sufficient bonding force, and a length of about 20 to 30 times the diameter of the columnar main bars 20 and 101 is sufficient.

  The sheath tube 30 is filled with mortar as a grout material during construction of the reinforced concrete column. For this reason, an injection passage 10 a for injecting mortar is formed in the concrete portion 10. The injection passage 10 a opens to the side surface of the concrete portion 10 and communicates with the upper end openings of one or more sheath tubes 30. The mortar injected from the injection passage 10 a is filled in the sheath tube 30, and a part of the mortar passes through the sheath tube 30 and is a joint material 10 b between the lower end surface of the concrete portion 10 and the upper end surface of the concrete member 100. It becomes. By forming such an injection passage 10a, the operation of injecting mortar during construction of the reinforced concrete column can be facilitated.

  The columnar reinforcement 20 is located on the same axis (line L1) as the sheath tube 30, and is parallel to the first linear portion 21 projecting upward from the upper end surface of the concrete portion 10 and the axis (line L1) of the sheath tube 30. The second linear portion 22 that extends and is arranged along the sheath tube 30 and forms a lap joint with the columnar muscle 101 via the sheath tube 30 is connected to the first linear portion 21 and the second linear portion 22. And a bent portion 23. The columnar reinforcement 20 is integrally formed so as to have a first linear portion 21, a second linear portion 22, and a bent portion 23, for example, by bending a conventional linear columnar reinforcement. .

  The second linear portion 22 has a lower end located in the vicinity of the lower end surface of the concrete portion 10. Moreover, since the 2nd linear part 22 comprises the lap | joint joint via the column main reinforcement 101 inserted in the sheath pipe | tube 30 and the sheath pipe | tube 30, the 2nd linear part 22 and the sheath pipe | tube 30 wind a reinforcing bar beforehand. In addition, it is desirable to manufacture the PCa member A so as to be embedded in the concrete portion 10 in a state where both are constrained to each other.

  As shown in FIG. 1C, in the present embodiment, the second linear portion 22 is located on the inner side of the concrete portion 10 than the sheath tube 30. In the case of the present embodiment, in particular, the second linear portion 22 is positioned on the inner side of the concrete portion 10 with respect to the sheath tube 30 in the direction orthogonal to the most adjacent side surface among the four side surfaces of the concrete member 10. Yes. Further, the second linear portions 22 located at the four corners of the concrete portion 10 are located on the inner side of the concrete portion 10 with respect to the sheath tube 30 in the diagonal direction of the four corners of the concrete portion 10.

  By arranging the second linear portion 22 in this way, a large space is secured between the adjacent sheath tubes 30 and between the column main bars 20, and the concrete constituting the concrete portion 10 is produced in the space when the PCa member A is manufactured. Filling is facilitated and occurrence of insufficient filling is prevented.

  A hoop muscle 40 is wound around each sheath tube 30. Further, the hoop bars 40 are also wound around the first linear portions 21 and the bent portions 23 of the column main bars 20. For example, the hoop muscles 40 having a diameter of 10 mm or 13 mm can be arranged at a pitch of about 100 mm. Since the circumference around each sheath tube 30, each first linear portion 21, and each bent portion 23 is different, it is desirable to use a hoop muscle 40 having a different circumference depending on the arrangement site. If the sheath tube 30 is thin, the circumferences around the sheath tubes 30 and the first linear portions 21 are substantially the same, and the hoop muscles 40 having the same circumference may be used.

  Here, in the case where the distance between the adjacent sheath tubes 30 and the columnar reinforcing bars 20 is originally large so that insufficient filling of the concrete does not occur, the second linear portion 22 is disposed as shown in FIG. can do. 2B and 2C are cross-sectional views when the arrangement position of the linear portion 22 is changed (FIG. 2B is equivalent to the line YY in FIG. 1A, and FIG. (Corresponding to line XX in FIG. 1A).

  In the case of the example shown in FIG. 2B, the second linear portion 22 is arranged so as to be in contact with the virtual envelope surrounding the sheath tube 30 (in other words, the outline of the hoop muscle 40) from the inside. . In this case, the distances between the sets of the sheath tube 30 and the second linear portion 22 are close to each other, but the circumferential lengths around the first linear portions 21 and the bent portions 23 are substantially the same. Therefore, it is not necessary to use the hoop muscle 40 having a different circumference depending on the arrangement site. Accordingly, the hoop muscle 40 having the same circumference can be used.

  Next, as shown in FIG. 2 (a), the bent portion 23 is bent at both ends thereof, and the first linear portion 21 and the second linear portion 22 follow this. When an earthquake or the like acts on a building using the PCa member A, a tensile load indicated by F in the figure acts on the column main bars 20. As a component force of the tensile load F, the load F1 acts on the bending point. When this load F1 is large, there is a concern that the structural performance of the reinforced concrete column formed by the PCa member A is impaired.

  Therefore, it is desirable that the bending angle θ in the figure is such that tan θ is 1/6 or less. When tan θ exceeds 1/6, the hoop muscle 40 wound around each bent portion 23 is of a larger diameter (for example, 16 mm, 19 mm) or the hoop muscle 40 is disposed. It is desirable to reinforce the bent portion 23 by making the pitch denser (for example, about 50 mm). In addition, as shown to Fig.1 (a), the restraining force of the bending part 23 can be heightened by arrange | positioning the hoop muscle 40 at a bending point.

  In the PCa member A having such a configuration, the cost can be reduced by using the relatively inexpensive sheath tube 30. Since the cover thickness around the sheath tube 30 is substantially the same as the cover thickness around the first linear portion 21, the problem of insufficient cover thickness is also solved.

  The total length of the sheath tube 30 is sufficient for a lap joint between the second linear portion 22 and the columnar main bar 101 (about 20 to 30 times the column main bar diameter), so that the sheath tube 30 and this are filled. The amount of grout material (mortar) used can be reduced. Moreover, by making the connection structure between the column main bars by the lap joint, it can be manufactured at a lower cost and more easily than the case of the reinforcing bar lap joint. Therefore, the cost of manufacturing the PCa member A and constructing the reinforced concrete column can be reduced.

  Moreover, since the 1st linear part 21 of the column main reinforcement 20 and the sheath pipe | tube 30 are located on the same axis | shaft, the 1st linear part 21 and the column main reinforcement 101 of the concrete member 100 are located on the same axis. Therefore, it is possible to construct a reinforced concrete column with a single PCa member A, and it is possible to construct a reinforced concrete column more easily and at a lower cost than when a plurality of types of PCa members are required.

(A) is structure explanatory drawing of PCa member A which concerns on one Embodiment of this invention, (b) is sectional drawing in alignment with line XX of Fig.1 (a), (c) is the line of Fig.1 (a). It is sectional drawing which follows YY. (A) is an enlarged view of the bent portion 23, (b) is a cross-sectional view in the case of another embodiment (corresponding to line YY in FIG. 1 (a)), and (c) is a cross-section in the case of another embodiment. It is a figure (equivalent to the line XX of Fig.1 (a)).

Explanation of symbols

A PCa member 10 Concrete portion 20 Column main reinforcement 21 First linear portion 22 Second linear portion 23 Bent portion 30 Sheath tube 100, 200 Concrete member 101 Column main reinforcement

Claims (3)

In a PCa member for a reinforced concrete column having a column main reinforcement,
One end is opened in the end surface of the PCa member, the other end is embedded in the PCa member so that it is located in the PCa member, and the column main reinforcement of the concrete member connected to the PCa member is inserted and the grout material is filled. A sheath tube
The column main reinforcement of the PCa member is
A first linear portion located coaxially with the sheath tube;
A second linear portion arranged along the sheath tube and constituting a lap joint with the column main reinforcement of the concrete member inserted into the sheath tube;
A bent portion connecting the first and second linear portions; and
A PCa member characterized by comprising:   2. The PCa member according to claim 1, wherein the second linear portion is disposed on an inner side of the PCa member with respect to the sheath tube. Furthermore,
3. The PCa member according to claim 1, wherein an opening for opening the side wall of the PCa member and an injection passage for injecting the grout material into the sheath tube are formed. 4.

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