JP2016205051A - Construction method for structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction method for a structure, which can shorten a construction period.SOLUTION: A construction method for a structure 10 includes: a precast foundation member installation step of installing a precast foundation member 20 on ground G; an upper structure construction step of constructing an upper structure 14 supported by the precast foundation member 20; and a foundation base part formation step of forming a foundation base part 40 by placing concrete on the periphery of the precast foundation member 20 in parallel with the upper structure construction step.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a construction method for a structure.

  A foundation construction method is known in which a rising portion that is raised from a foundation and supports a column or the like of an upper structure is precast (for example, see Patent Documents 1 and 2).

  In the foundation construction method disclosed in Patent Document 1, a footing is formed by placing concrete around a precast rising portion.

JP-A-6-306874 Japanese Patent Laid-Open No. 6-57661

  However, in the technique disclosed in Patent Document 1, since the upper structure is constructed after the concrete placed around the rising portion is cured, the construction period may be prolonged.

  In view of the above facts, an object of the present invention is to provide a method for constructing a structure that can shorten the construction period.

  The construction method of the structure according to claim 1, the precast foundation member installation step of installing a precast foundation member on the ground, the upper structure construction step of constructing the upper structure supported by the precast foundation member, In parallel with the upper structure construction step, a foundation base portion forming step of forming a foundation base portion by placing concrete around the precast foundation member.

  According to the construction method for a structure according to claim 1, first, in the precast foundation member installation step, the precast foundation member is installed on the ground. Next, in the upper structure construction process, the upper structure supported by the precast foundation member is constructed. And a base base part formation process is performed in parallel with a superstructure construction process. In this foundation base portion forming step, concrete is cast around the precast foundation member to form the foundation base portion.

  Thus, according to the present invention, first, in the precast foundation member installation step, the upper structure construction step and the foundation base portion formation step can be performed in parallel by installing the precast foundation member on the ground. . Therefore, the construction period can be shortened compared with the case where the upper structure is constructed after the foundation base portion is formed around the precast foundation member.

  The structure construction method according to claim 2 is the structure construction method according to claim 1, wherein the precast foundation member includes a foundation core portion embedded in the foundation base portion, and a foundation core portion. In the upper structure construction process, at least a column or a beam joined to the joint is constructed.

  According to the construction method according to claim 2, the precast foundation member has a foundation core part embedded in the foundation base part and a joint part provided at an upper part of the foundation core part. This precast foundation member is installed on the ground in the precast foundation member installation step. Next, in the upper structure construction process, at least a column or a beam to be joined to the joint portion in the precast foundation member installation process is constructed.

  In this way, by providing the joint portion in the precast base member in advance, the column or beam can be easily joined to the precast base member. Therefore, the construction period can be further shortened.

  The structure construction method according to claim 3 is the structure construction method according to claim 1 or 2, wherein the precast foundation member has an extending member extending from a side surface of a lower end portion. The extending member is embedded in a lower end portion of the base base portion in the base base portion forming step.

  According to the construction method for a structure according to claim 3, the precast foundation member has the extending member extending from the side surface of the lower end portion. This extending member is embedded in the lower end portion of the base base portion in the base base portion forming step.

  Here, the load of the upper structure supported by the precast base member is transmitted as a bending moment to the base base portion via the precast base member. Since this bending moment becomes maximum at the connection portion (boundary portion) between the precast foundation member and the foundation base portion, the connection portion is easily damaged.

  In contrast, in the present invention, as described above, the precast base member has an extending member extending from the side surface of the lower end portion thereof. This extending member is embedded in the lower end portion of the base base portion in the base base portion forming step. Thereby, the connection part of a precast foundation member and a foundation base part is reinforced by the extending member. Therefore, the breakage of the connection portion between the precast foundation member and the foundation base portion is suppressed.

  In addition, by embedding extension members in the lower end portion of the precast foundation member and the lower end portion of the foundation base portion, for example, in the case of embedding the extension member in the upper end portion of the precast foundation member and the upper end portion of the foundation base portion As compared with the above, the extending member efficiently resists the bending moment acting on the base base portion. Therefore, breakage of the connection portion between the precast foundation member and the foundation base portion is further suppressed.

  As explained above, according to the structure construction method of the present invention, the construction period can be shortened.

It is a longitudinal cross-sectional view which shows the structure constructed | assembled by the construction method of the structure which concerns on one Embodiment of this invention. It is a top view which shows the precast foundation member and foundation base part which are shown by FIG. (A) is a longitudinal cross-sectional view explaining the precast foundation member installation process in one Embodiment, (B) is a longitudinal cross-sectional view explaining the upper structure construction process in one Embodiment. (A) And (B) is a longitudinal cross-sectional view explaining the basic | foundation base part formation process in one Embodiment. It is a longitudinal cross-sectional view corresponding to FIG. 4 (A) which shows the modification of the precast base member shown by FIG. It is a perspective view which shows the modification of the precast base member shown by FIG. It is a longitudinal cross-sectional view corresponding to FIG. 3 (B) which shows the modification of the precast base member shown by FIG. It is a longitudinal cross-sectional view which shows the modification of the basic | foundation base part shown by FIG.

  Hereinafter, a construction method for a structure according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a structure 10 constructed by the structure construction method according to the present embodiment. The structure 10 includes a foundation 12 and an upper structure 14 supported by the foundation 12.

  The foundation 12 is an independent footing foundation formed on the ground G. The foundation 12 includes a precast foundation member 20 made of precast concrete and a foundation base portion 40 formed of cast-in-place concrete.

  The precast base member 20 is formed in a prismatic shape. The precast foundation member 20 has a foundation core portion 22 and a joint portion 28. The foundation core 22 constitutes the lower part of the precast foundation member 20 and is installed on the discarded concrete 16 cast on the ground G. Note that the precast base member 20 is not limited to a prismatic shape, and may be, for example, a cylindrical shape.

  A plurality of bending reinforcing bars 24 are embedded in the lower end portion of the basic core portion 22. In addition, a plurality of pulling resistance bars 26 are embedded in the upper end portion of the basic core portion 22. The plurality of bending reinforcing bars 24 and the pulling resistance bars 26 extend in the lateral direction from the respective side surfaces 22S of the foundation core part 22, and are embedded in the foundation base part 40 described later. The foundation core portion 22 and the foundation base portion 40 are integrated with each other through the bending reinforcing bars 24 and the pulling resistance bars 26. The bending reinforcing bar 24 is an example of an extending member.

  In addition, a joint portion 28 is provided on the upper portion (above) of the basic core portion 22. The joint portion 28 is made of SRC and constitutes the upper portion of the precast base member 20. A column bracket 30 for the column 32 and a plurality of beam brackets 34 for the foundation beam 36 are embedded in the joint portion 28.

  The column bracket 30 is formed of, for example, a rectangular steel pipe, and a lower portion is embedded in the joint portion 28 and an upper portion projects upward from the upper surface 28U of the joint portion 28. A column 32 constituting the upper structure 14 is joined to the upper end portion of the column bracket 30 by welding, bolts, or the like. The column 32 is formed of, for example, a square steel pipe. Note that the column bracket 30 and the column 32 are not limited to square steel pipes, and may be, for example, H-shaped steel.

  Each beam bracket 34 is formed of, for example, H-shaped steel, and one end side thereof is embedded in the joint portion 28, and the other end side protrudes from the side surface of the joint portion 28. One end side of each beam bracket 34 is joined to the side surface of the column bracket 30. On the other hand, one end of the foundation beam 36 constituting the upper structure 14 is joined to the other end of the beam bracket 34 by welding, bolts, or the like. The base beam 36 as a beam is formed of, for example, an H-shaped steel. The other end of the foundation beam 36 is joined to a beam bracket of another adjacent precast foundation member. The column bracket 30 and the foundation beam 36 are not limited to the H-shaped steel, and may be, for example, an I-shaped steel, a C-shaped steel, a rectangular steel pipe, or the like.

  The foundation base portion 40 is formed by placing concrete around the foundation core portion 22. As shown in FIG. 2, the base base portion 40 is formed in a rectangular shape in plan view. The ground contact area of the foundation 12 with respect to the ground G is increased by the foundation base portion 40. In addition, the width W and thickness T (refer FIG. 1) of the foundation base part 40 are suitably set according to the vertical load F of the upper structure 14 which the foundation 12 bears, for example. Further, the shape of the base base portion 40 is not limited to a rectangular shape in plan view, and may be, for example, a circular shape.

  As shown in FIG. 1, a gap D between the upper surface 40U of the foundation base portion 40 and the lower surfaces 34L and 36L of the beam bracket 34 and the foundation beam 36 is filled with a cement filler 38 such as mortar or grout. Yes. As a result, the reaction force R received by the foundation base portion 40 from the ground G is transmitted to the beam bracket 34 and the foundation beam 36 via the cement filler 38. The cement filler 38 may be provided as necessary and can be omitted as appropriate.

  Next, an example of a construction method for the structure 10 will be described.

  First, the precast foundation member installation process will be described. In the precast foundation member installation step, first, as shown in FIG. 3A, the discarded concrete 16 is placed on the ground G, and ink is drawn out. Next, the precast foundation member 20 is lifted by a lifting machine (not shown), and the precast foundation member 20 is installed at a predetermined position on the discarded concrete 16 with the foundation core portion 22 facing down. At this time, the beam bracket 34 protruding from the joint portion 28 of the precast base member 20 is positioned so as to face a predetermined direction.

  The discarded concrete 16 may be constructed as necessary and can be omitted as appropriate.

  Next, as shown in FIG. 3B, in the upper structure construction process, the end of the foundation beam 36 is joined to each beam bracket 34 of the precast foundation member 20 by welding, bolts, or the like. Further, the pillar 32 is erected on the pillar bracket 30 of the precast base member 20, and the pillar bracket 30 and the pillar 32 are joined by welding, bolts, or the like. Further, on the pillar 32, for example, an upper floor pillar or beam (not shown) for forming the upper structure 14 is constructed.

  Note that either the foundation beam 36 and the column 32 may be constructed first, or both may be constructed in parallel.

  Here, as the construction of the upper structure 14 progresses, the vertical load F introduced into the precast foundation member 20 gradually increases, so that the ground pressure P generated on the lower surface (ground surface) 22L of the foundation core portion 22 also gradually increases. Become bigger. If the ground pressure P generated on the lower surface 22L of the basic core portion 22 exceeds a predetermined value (for example, the compressive strength of the basic core portion 22), the basic core portion 22 may be damaged.

  As a countermeasure, in this embodiment, before the ground pressure P generated on the lower surface 22L of the foundation core portion 22 exceeds a predetermined value, a foundation base portion forming process is performed in parallel with the upper structure construction process, and the foundation core portion 22 A base base portion 40 is formed around

  Specifically, in the base base portion forming step, first, as shown in FIG. 4A, a mold 42 is formed around the base core portion 22 of the precast base member 20 so as to surround the base core portion 22. Temporary. Next, in the formwork 42, the basic bar arrangement 44 is appropriately arranged and concrete is placed. And when concrete hardens | cures, the base base part 40 will be formed in the circumference | surroundings of the base core part 22, as FIG.4 (B) shows. At this time, the bending reinforcing bars 24 and the pulling resistance bars 26 protruding from the side surface 22 </ b> S of the foundation core portion 22 are embedded in the foundation base portion 40. Thereby, the foundation core part 22 and the foundation base part 40 are integrated through the bending reinforcement bar 24 and the pulling resistance bar 26. The formwork 42 is appropriately removed after the concrete for the base base portion 40 is cured.

  By forming the base base portion 40 around the base core portion 22 in this way, the vertical load F transmitted from the upper structure 14 to the precast base member 20 is applied to the base base portion 40 via the base core portion 22. Communicated. That is, the vertical load F of the upper structure 14 is distributed and transmitted to the ground G through the discarded concrete 16 from the lower surfaces 22L and 40L of the foundation core portion 22 and the foundation base portion 40. Accordingly, since the ground pressure P generated on the lower surface 22L of the basic core portion 22 is reduced, damage to the basic core portion 22 and the like are suppressed.

  Next, as shown in FIG. 1, in the filling material filling process, cement such as grout or mortar is formed in the gap D between the upper surface 40U of the foundation base portion 40 and the lower surfaces 34L and 36L of the beam bracket 34 and the foundation beam 36. The system filler 38 is filled. As a result, the reaction force R received by the foundation base portion 40 from the ground G is transmitted to the beam bracket 34 and the foundation beam 36 via the cement filler 38. Therefore, damage to the base base portion 40 is suppressed.

  Next, the effect of this embodiment will be described.

  As described above, according to the construction method of the structure 10 according to the present embodiment, in the precast foundation member installation process, by installing the precast foundation member 20 on the ground G, the upper structure construction process and the foundation base portion. The formation process can be performed in parallel. Therefore, compared with the case where the upper structure 14 is constructed after the foundation base portion 40 is formed around the foundation core portion 22 of the precast foundation member 20, the construction period can be shortened.

  Further, by providing the joint portion 28 in the precast foundation member 20 in advance, the column 32 and the foundation beam 36 can be easily joined to the precast foundation member 20. Therefore, the construction period can be further shortened.

  Furthermore, in this embodiment, before the ground pressure P generated on the lower surface 22L of the foundation core portion 22 with the construction of the upper structure 14 exceeds a predetermined value, concrete is placed around the foundation core portion 22. A base base portion 40 is formed. Thereby, since the vertical load F of the upper structure 14 is distributed and transmitted to the ground G through the discarded concrete 16 from the lower surfaces 22L and 40L of the basic core portion 22 and the basic base portion 40, the lower surface of the basic core portion 22 is transmitted. The ground pressure P generated at 22L decreases. Therefore, damage to the basic core portion 22 is suppressed.

  Here, as a method of reducing the contact pressure P generated on the lower surface 22 </ b> L of the foundation core portion 22, for example, a precast foundation member in which the foundation base portion 40 is integrated in advance with the precast foundation member 20 can be considered. . In this case, as in the present embodiment, the vertical load F of the upper structure 14 is distributed and transmitted from the bottom surface 22L, 40L of the foundation core portion 22 and the foundation base portion 40 to the ground G. Accordingly, since the ground pressure P generated on the lower surface 22L of the basic core portion 22 is reduced, damage to the basic core portion 22 and the like can be suppressed.

  However, if the base base portion 40 is integrated with the precast base member 20 in advance, the weight of the precast base member increases. There is a possibility that the workability may be reduced due to a decrease.

  On the other hand, the foundation base part 40 is not integrated with the precast foundation member 20 in the present embodiment in advance. Therefore, since the precast foundation member 20 becomes light, the liftability and transportability of the precast foundation member 20 are improved.

  In the present embodiment, the foundation base portion 40 is formed by placing concrete around the foundation core portion 22 of the precast foundation member 20 at the site. Therefore, the size and strength of the base base portion 40 can be appropriately changed according to the vertical load F of the upper structure 14 borne by the precast base member 20 (base 14). Therefore, the versatility of the precast base member 20 is improved.

  Further, the vertical load F of the upper structure 14 borne by the precast foundation member 20 is transmitted as a bending moment M (see FIG. 1) to the foundation base portion 40 via the foundation core portion 22. Since this bending moment M becomes maximum at the connecting portion (boundary portion) between the basic core portion 22 and the basic base portion 40, the connecting portion is easily damaged.

  As a countermeasure, in this embodiment, the foundation core portion 22 is provided with a bending reinforcing bar 24. The bending reinforcing bars 24 extend laterally from the side surface 22S of the foundation core portion 22 and are embedded in the foundation base portion 40. The bent reinforcing bars 24 reinforce the connecting portion between the foundation core portion 22 and the foundation base portion 40. Therefore, damage to the connecting portion between the basic core portion 22 and the basic base portion 40 is suppressed.

  Moreover, the bending reinforcing bar 24 is embedded across the lower end portion of the foundation core portion 22 and the lower end portion of the foundation base portion 40. Thereby, for example, the bending reinforcing bar 24 is more efficient with respect to the bending moment M than when the bending reinforcing bar 24 is embedded between the upper end of the foundation core portion 22 and the upper end of the foundation base portion 40. Resist. Therefore, the damage of the connection part of the basic core part 22 and the basic base part 40 is further suppressed.

  A pulling resistance bar 26 is embedded in the upper end portion of the basic core portion 22. The pulling resistance bars 26 extend in the lateral direction from the side surface 22S of the upper end portion of the foundation core portion 22 and are embedded in the upper end portion of the foundation base portion 40.

  Here, at the time of an earthquake, for example, an upward pulling force S (see FIG. 1) may act on the precast base member 20 due to a falling moment or the like generated in the upper structure 14. In the present embodiment, the pulling resistance bar 26 efficiently resists such a pulling force S. Thereby, since the fall of the upper structure 14 is suppressed, seismic performance improves.

  Next, a modification of the above embodiment will be described.

  In the said embodiment, although the joint part 28 of the precast base member 20 is made into SRC structure, the said embodiment is not restricted to this. The joint portion 28 of the precast foundation member 20 can be appropriately changed according to the structure type of the beam or column to be joined. For example, the steel core joint portion may be provided integrally with the foundation core portion 22. Moreover, in the precast base member 50 shown by FIG. 5, the joint part 52 is made into RC structure.

  Specifically, the precast foundation member 50 has a foundation core part 51 and a joint part 52 provided on the upper part of the foundation core part 51. Upper and lower beam main bars 54 are embedded in the joint portion 52. These beam main bars 54 protrude from the side surface 52S of the joint portion 52 and are embedded in the end portion of the foundation beam 56 made of RC. Thereby, the joint part 52 of the precast foundation member 50 and the edge part of the foundation beam 56 are joined.

  In addition, a plurality of column main bars 58 are embedded in the joint portion 52. These column main bars 58 protrude upward from the upper surface 52U of the joint portion 52, and are embedded in the column base portion of the column 60 made of RC. Thereby, the pillar 60 is joined to the joint portion 52. In addition, the foundation beam 56 and the pillar 60 may be formed with spot cast concrete, and may be formed with precast concrete.

  Next, in the precast base member 70 shown in FIG. 6, a beam portion 72 </ b> A is formed integrally with the joint portion 72. The beam portion 72A is joined to an RC foundation beam (not shown). Further, in the precast foundation member 70 shown in FIG. 6, a protrusion 71 </ b> A corresponding to the beam shape of the beam 72 </ b> A is integrally formed on the foundation core 71. It is also possible to increase the ground contact area (the area of the lower surface) of the basic core portion 71 by the protruding portion 71A.

  Next, in the said embodiment, although the joint part 28 is integrally formed in the precast base member 20, the said embodiment is not restricted to this. For example, in the precast base member 80 shown in FIG. 7, the joint portion is omitted.

  Specifically, the precast foundation member 80 has a foundation core portion 81. A plurality of anchor bars 82 are embedded in the basic core portion 81 so as to protrude upward from the upper surface of the basic core portion 81 (precast basic member 80). A base plate 86 of a steel column 84 is fixed to these anchor bars 82 with nuts 88. Thereby, the pillar 84 is joined to and supported by the precast base member 80.

  In this way, it is possible to omit the joint from the precast foundation member 80 and join the pillar to the foundation core part 81. In addition, the joining structure of the basic core part 81 and the pillar 84 can be changed suitably. Moreover, although illustration is abbreviate | omitted, it is also possible to join the foundation core part 81, a pillar, and a beam, for example by installing a pillar and a beam on the foundation core part 81 in the field, and placing concrete. . That is, it is also possible to form a joint part on the basic core part 81 at the site.

  Next, in the said embodiment, although the basic | foundation base part 40 is made into a footing, the said embodiment is not restricted to this. For example, the foundation base 90 shown in FIG. 8 is a solid foundation slab. The foundation base portion 90 is formed by placing concrete over the foundation core portions 22 of the plurality of precast foundation members 20 in the foundation base portion forming step. Although not shown, the foundation base portion may be a fabric foundation footing.

  Next, in the said embodiment, although the pillar 32 and the foundation beam 36 were joined to the joint part 28 of the precast foundation member 20, the example which performed the foundation base part formation process was shown, However, The said embodiment is not restricted to this. Absent. For example, it is possible to perform the foundation base portion forming step in parallel with the construction of the pillar 32 and the foundation beam 36.

  Next, in the said embodiment, although the upper surface 40U of the base base part 40 is made into a substantially horizontal horizontal surface, the upper surface of the base base part 40 may be made into an inclined surface.

  Next, in the above embodiment, the bending reinforcement bar 24 and the pulling resistance bar 26 are integrally provided on the precast base member 20, but the bending reinforcing bar 24 and the pulling resistance bar 26 may be provided as necessary. It can be omitted as appropriate.

  As mentioned above, although one embodiment of the present invention was described, the present invention is not limited to such an embodiment, and one embodiment and various modifications may be used in combination as appropriate, and the gist of the present invention will be described. Of course, various embodiments can be implemented without departing from the scope.

DESCRIPTION OF SYMBOLS 10 Structure 14 Upper structure 20 Precast foundation member 22 Foundation core part 24 Bending reinforcement (extension member)
28 Joint 32 Column (Superstructure)
36 Foundation beam (superstructure)
40 foundation base part 50 precast foundation member 51 foundation core part 52 joint part 56 foundation beam (superstructure)
60 pillars (superstructure)
70 Precast foundation member 71 Foundation core part 72 Joint part 80 Precast foundation member 81 Foundation core part 84 Column (upper structure)
90 Foundation base part G Ground

Claims (3)

A precast foundation member installation process for installing a precast foundation member on the ground;
An upper structure construction process for constructing an upper structure supported by the precast foundation member;
In parallel with the upper structure construction step, a foundation base portion forming step for forming a foundation base portion by placing concrete around the precast foundation member,
A construction method for a structure comprising: The precast foundation member has a foundation core part embedded in the foundation base part, and a joint part provided at an upper part of the foundation core part,
In the upper structure construction process, at least a column or a beam to be joined to the joint is constructed.
The construction method of the structure of Claim 1. The precast foundation member has an extending member extending from the side surface of the lower end portion,
The extending member is embedded in a lower end portion of the base base portion in the base base portion forming step.
The construction method of the structure of Claim 1 or Claim 2.

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