Leg fixing structure and leg fixing method of extension structure

Abstract

To provide a leg fixing structure and a leg fixing method of an extension structure that can eliminate the need for chipping construction of a continuous footing and filling construction with concrete, and that eliminates the risk of interference between anchor bolts that fix a leg plate to the continuous footing and a main reinforcement of a rising portion.SOLUTION: In a leg fixing structure 80 of an extension structure, a leg plate 65 of an extension structure 60 is fixed to a rising portion 11 of an existing continuous footing 10 by an anchor bolt 70. Each of a pair of leg members 20 is fixed to each of a pair of side surfaces 12 of the rising portion 11. Upper parts of the pair of leg members 20 are connected by an anchor plate 30 that straddles a top end 13 of the rising portion 11 to form a leg fixing jig 40. A first bolt hole 35 included in the anchor plate 30 and a second bolt hole 66 included in the leg plate 65 are aligned, and the anchor bolt 70 is inserted to bolt-join the anchor plate 30 and the leg plate 65 together.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a leg fixing structure and a leg fixing method for an extension structure. [Background technology]

[0002] There is an increasing demand for seismic reinforcement work, in which a bearing wall is added to an existing slab footing after construction. A bearing wall has a structure in which a pair of columns are connected by a brace or a cross member that undergoes plastic deformation, and therefore, the addition of a bearing wall to an existing slab footing is generally carried out by fixing the base plate of the column that constitutes the bearing wall to the top end of the rising part of the slab footing via an anchor bolt.

[0003] In the above-mentioned structure for fixing the foot plate to the top of the rising part, in order to resist the large pulling force acting through the column, the anchor bolt is installed by chipping the installation location at the top of the rising part, and concrete is filled in the chipped area. However, this construction method requires chipping the slab footing and filling it with concrete, which requires a relatively large construction space and a lot of labor. In addition, there is a concern that chipping a part of the slab footing may damage the slab footing itself.

[0004] Therefore, by drilling holes in the top end of the rising part and embedding post-installed anchors in the holes, the problems caused by the chipping construction of the slab footing and the filling construction of concrete can be solved. However, in a typical slab footing, multiple main reinforcements are arranged at intervals in the longitudinal direction of the slab footing at the width center of the rising part, so if the installation position of the anchor bolt is set to the width center of the top end of the rising part, there is a risk of interference with the main reinforcement of the rising part. Therefore, if the installation position of the anchor bolt is set to a position eccentric from the width center of the rising part to prevent interference with the main reinforcement, then in a typical slab footing where the width dimension of the rising part is not large, there is a high possibility that the anchor bolt will not be able to be fixed to the rising part with a predetermined cover, which is not preferable.

[0005] In view of the above, there is a need for a leg fixing structure and leg fixing method for an extension structure which, when fixing the leg plate of an extension structure to the rising portion of a slab footing with anchor bolts, makes it unnecessary to chip the slab footing and fill it with concrete, and which eliminates the risk of interference between the anchor bolts fixing the leg plate to the slab footing and the main reinforcement of the rising portion.

[0006] Here, Patent Document 1 proposes a method for fixing a wooden through-column, which can improve earthquake resistance by firmly connecting the through-column to a slab footing. In this fixing method, a column base metal fitting, which is a cylindrical frame with an open top and vertically integrally formed with a base plate, is placed on a slab footing with an anchor bolt buried in it and fastened and fixed by the anchor bolt, and after inserting the lower end of the wooden through-column into the cylindrical frame, a bolt is passed horizontally through the cylindrical frame and the wooden through-column and fastened. The anchor bolt is provided at the top end of the rising part of the slab footing, in the center of its width. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 11-200511 Summary of the Invention [Problem to be solved by the invention]

[0008] Even in the method of fixing a wooden through-hole column described in Patent Document 1, the anchor bolt that fixes the wooden through-hole column to the slab footing is located at the center of the width of the top end of the raised part of the slab footing, which means there is a risk of the above-mentioned problem, i.e., interference between the anchor bolt and the main reinforcement of the raised part.

[0009] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a leg fixing structure and leg fixing method for an extension structure which, when fixing the leg plate of an extension structure to the rising portion of a slab footing with anchor bolts, eliminates the need to chip the slab footing and fill it with concrete, and which eliminates the risk of interference between the anchor bolts fixing the leg plate to the slab footing and the main reinforcement of the rising portion. [Means for solving the problem]

[0010] In order to achieve the above object, one aspect of the leg fixing structure of the extension structure according to the present invention is to A leg fixing structure for an extension structure in which a leg plate of an extension structure is fixed to a rising portion of an existing slab footing by an anchor bolt, A pair of legs are fixed to each of a pair of side surfaces of the rising portion, The upper portions of the pair of legs are connected to an anchor plate that spans the top end of the rising portion to form a leg fixing jig, The present invention is characterized in that a first bolt hole in the anchor plate and a second bolt hole in the leg plate are aligned, and the anchor bolt is inserted to bolt the anchor plate and the leg plate together.

[0011] According to this aspect, leg members are fixed to each of a pair of side surfaces of the rising portion, the upper parts of the pair of leg members are connected by an anchor plate that straddles the top end of the rising portion to form a leg fixing jig, and the anchor plate and the leg plate are bolted together with anchor bolts, so that the leg plate of the extension structure is fixed to the side surface instead of the top end of the rising portion, thereby eliminating interference between the main reinforcement at the center of the width of the rising portion and the anchor bolts, and a leg fixing structure of the extension structure to the slab footing can be formed. Note that in this aspect, the anchor bolts are not buried inside the slab footing, but are bolts that connect the anchor plate and the leg plate above the top end of the rising portion.

[0012] Here, the method of fixing the legs to the side surfaces of the rising portion includes a method of installing post-installed anchors in anchor holes provided in the width direction of the rising portion, a method of installing through-bolts in through-holes that span a pair of side surfaces of the rising portion, etc. Also, examples of the additional structure include columns that constitute load-bearing walls and general columns (additional columns).

[0013] In another aspect of the leg fixing structure of the extension structure according to the present invention, The leg member includes a shaped steel member and a top plate joined to a top portion of the shaped steel member, the top plate includes a third bolt hole, and the anchor plate further includes a fourth bolt hole separate from the first bolt hole; The third bolt hole and the fourth bolt hole are aligned and a fixing bolt is inserted through them to bolt the top plate and the anchor plate together.

[0014] According to this aspect, the legs include shaped steel members fixed to the sides of the rising portions and top plates joined to the tops of the shaped steel members, and the top plates of the pair of legs are joined to the anchor plate by bolts, so that the anchor plate can be joined to the pair of legs in a stable position. Here, examples of the shaped steel members include channel steel and angle steel.

[0015] In another aspect of the leg fixing structure of the extension structure according to the present invention, The fourth bolt hole is characterized in that it is an elongated hole that is long in the width direction of the rising portion.

[0016] According to the present embodiment, the fourth bolt hole of the anchor plate, which is later aligned with the third bolt hole of the top plate, is a long hole that is long in the width direction of the raised portion. Therefore, even if there are manufacturing errors or construction errors in each component, the third bolt hole and the fourth bolt hole can be reliably aligned, ensuring a reliable bolt connection between a pair of leg members and the anchor plate.

[0017] Another aspect of the leg fixing structure of the extension structure according to the present invention is as follows: The steel section is fixed to the rising portion by a plurality of through bolts or post-installed anchors spaced apart in the longitudinal direction.

[0018] According to this aspect, the shaped steel material constituting the leg member is fixed to the rising portion with a plurality of through-bolts or post-installed anchors spaced apart in its longitudinal direction (longitudinal direction, vertical direction), so that the cone fracture surface originating from the through-bolt located at the lowest end can withstand the pull-out force acting from the added structure. In other words, the lowest end through-bolt is installed at a position (level) where a cone fracture surface with an area capable of withstanding the design pull-out force can be formed, and one or more through-bolts are installed at a predetermined interval above it.

[0019] Another aspect of the leg fixing structure of the extension structure according to the present invention is as follows: A plurality of leg fixing jigs are fixed to the rising portion in the longitudinal direction thereof, and leg plates of the extension structure are fixed to the plurality of leg fixing jigs.

[0020] According to this embodiment, multiple (e.g., two) leg fixing fixtures formed by a pair of leg members and anchor plates are fixed in the longitudinal direction of the rising portion, and the leg plates of the extension structure are fixed to these multiple leg fixing fixtures, thereby forming a stable leg fixing structure with high fixing strength to the slab foundation.

[0021] Another aspect of the leg fixing structure of the extension structure according to the present invention is as follows: The extension structure is characterized in that it is a column forming a load-bearing wall that is added to an existing building through post-construction.

[0022] According to this aspect, the added structure is a column that forms a load-bearing wall that is added to an existing building through post-construction, so that the legs of the load-bearing wall are fixed with high strength to the existing slab footing, thereby providing an excellent earthquake-resistant reinforcement structure for the existing building.

[0023] In addition, one aspect of the method for fixing a leg of an extension structure according to the present invention is to A method for fixing the legs of an extension structure by fixing the leg plate of the extension structure to the rising portion of an existing slab footing with an anchor bolt, a step of fixing a pair of legs to a pair of side surfaces of the rising portion, respectively; A step of connecting the upper parts of the pair of leg members with an anchor plate that spans the top end of the rising portion to form a leg fixing jig consisting of the pair of leg members and the anchor plate; The method is characterized by having a process of aligning a second bolt hole of the leg plate with a first bolt hole of the anchor plate, inserting the anchor bolt, and bolting the leg plate to the anchor plate.

[0024] According to this aspect, by fixing the legs to a pair of side surfaces of the rising part of the slab footing and connecting the upper parts of the pair of legs with an anchor plate that spans the top end of the rising part to form a leg fixing jig, even if the pair of side surfaces (surfaces) of the rising part of the existing slab footing have unevenness due to aging deterioration, construction errors, etc., the pair of legs can be fixed to each side surface without any gaps, and the pair of legs and the anchor plate can be strongly bolted together. For example, in a method in which a U-shaped leg fixing jig is manufactured in advance and fitted into the top end of the rising part, there are often cases in which the fitting is not possible or, conversely, a gap occurs between the side surfaces due to the unevenness of the pair of side surfaces of the rising part as described above.

[0025] Furthermore, since the leg fixing jig is stably and firmly fixed to the raised portion, the leg plate of the extension structure can be precisely and smoothly bolted to the anchor plate that constitutes this leg fixing jig. Effect of the Invention

[0026] As can be understood from the above explanation, according to the leg fixing structure and leg fixing method for an extension structure of the present invention, when fixing the leg plate of an extension structure to the rising portion of a slab footing with anchor bolts, it is possible to provide a leg fixing structure and leg fixing method for an extension structure which makes it unnecessary to chip the slab footing and fill it with concrete, and which does not have the risk of interference between the anchor bolts fixing the leg plate to the slab footing and the main reinforcement of the rising portion. [Brief description of the drawings]

[0027] [Figure 1] 10A to 10C are process diagrams showing an example of a method for fixing legs of an extension structure according to an embodiment. [Diagram 2] 1, a process diagram showing an example of a method for fixing a leg of an extension structure according to the embodiment. [Diagram 3] 5 is a process diagram showing an example of a leg fixing method for the extension structure according to the embodiment, following FIG. 2, and also shows a leg fixing structure according to the embodiment. FIG. [Figure 4] 4 is a view taken in the direction of the arrow IV in FIG. 3. [Diagram 5] FIG. 4 is a view taken along the arrows VV in FIG. 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, an example of a leg fixing method and a leg fixing structure for an extension structure according to an embodiment will be described with reference to the accompanying drawings. In this specification and the drawings, substantially identical components may be designated by the same reference numerals to avoid redundant description.

[0029] [Method and structure for fixing legs of extension structure according to embodiment] An example of a leg fixing method and a leg fixing structure of an extension structure according to an embodiment will be described with reference to Fig. 1 to Fig. 5. Here, Fig. 1 to Fig. 3 are process diagrams showing an example of a leg fixing method of an extension structure according to an embodiment, and Fig. 3 is a diagram showing the leg fixing structure according to an embodiment. Fig. 4 and Fig. 5 are views taken along the arrow IV in Fig. 3 and the arrow VV in Fig. 3, respectively.

[0030] The existing slab foundation 10 is a reinforced concrete foundation having a footing 15 buried in the ground G and a rising portion 11 rising vertically (e.g., vertically) from the footing 15, and is installed, for example, along the exterior wall line or interior partition line of an existing building.

[0031] The illustrated leg fixing method is a method for fixing a leg plate of a column constituting a bearing wall, which is an example of an additional structural body added to an existing building, to a rising portion 11. In this case, the additional structural body includes various structural bodies such as general additional columns in addition to bearing wall columns.

[0032] Although not shown in the figure, main reinforcement bars are installed at a predetermined interval (pitch) in the longitudinal direction at the center position in the width direction of the rising part 11 of the slab footing 10. Therefore, in the conventional method of fixing the leg plate of a general extension structure to the top end of the rising part with anchor bolts, there is a problem that the anchor bolts interfere with the main reinforcement bars when driven into the center position in the width direction of the rising part, which is not very wide. The leg fixing method in the illustrated example is a fixing method that solves this problem and makes it possible to firmly fix the leg plate of the extension structure to the rising part of the slab footing.

[0033] In the leg fixing method, first, a pair of leg members 20 are fixed to a pair of side surfaces 12 of a rising portion 11 of a continuous footing 10, respectively, as shown in FIG.

[0034] The leg member 20 comprises a channel steel 21 (an example of a shaped steel material) of a predetermined length, and a top plate 25 joined by welding to a top 22 of the shaped steel material 21. The top plate 25 has a third bolt hole 27. Here, the shaped steel material constituting the leg member may be an angle steel or the like.

[0035] When fixing the structural steel material 21 to each side surface 12, multiple (three in the illustrated example) through holes 14 are drilled across a pair of side surfaces 12 at predetermined intervals in the longitudinal direction (e.g., vertical direction) of the rising portion 11.

[0036] Next, the legs 20 are arranged on each side surface 12 so that the top plate 25 is flush with the top end 13 of the raised portion 11, and the two legs 20 are fixed to the pair of side surfaces 12 by inserting through-bolts 50 into corresponding bolt holes (not shown) opened in the webs of both channel steel beams 21 and tightening the nuts.

[0037] Here, instead of the method of drilling a through hole 14 in the rising portion 11 and inserting a through bolt 50, a method may be used in which a bolt hole of a predetermined length (not shown, which is a length shorter than the width of the rising portion 11) is drilled and the structural steel material is fixed to the rising portion 11 with a plurality of post-installed anchors (not shown).

[0038] Of the three through bolts 50, the distance t between the lowest through bolt 50 and the top end 13 of the raised portion 11 is set to a length that is capable of forming a cone breaking surface with the area required for the design described below (this concludes the process of fixing a pair of leg members).

[0039] Next, as shown in FIG. 2, the top plates 25 of the pair of legs 20 are connected with an anchor plate 30 that straddles the top ends 13 of the rising portions 11, thereby forming a leg fixing jig 40.

[0040] The anchor plate 30 has a first bolt hole 35 at its longitudinal center or approximately its longitudinal center, into which the second bolt hole 66 (see Figs. 3 and 4) of the leg plate 65 of the extension structure 60 is aligned and into which the anchor bolt 70 is inserted, and further has two fourth bolt holes 32 near the longitudinal ends. Here, the fourth bolt holes 32 are elongated holes that are long in the width direction of the rising portion 11.

[0041] An anchor plate 30 is placed on the top plates 25 of the two legs 20 fixed to a pair of side surfaces 12 and the top ends 13 of the rising portions 11, and the corresponding fourth bolt holes 32 are aligned with the third bolt holes 27 of each top plate 25.

[0042] In this case, since the fourth bolt hole 32 is a long hole that is long in the width direction of the rising portion 11, even if there are manufacturing errors in the leg material 20, anchor plate 30, and third bolt hole 27 relative to the top plate 25, and even if there are unevenness on the side surface 12 due to deterioration of the slab footing 10 over time, the third bolt hole 27 and the long hole 32 can be aligned, and insertion of the fixing bolt 56 can be guaranteed.

[0043] The anchor plate 30 and the top plate 25 are bolted together by inserting a fixing bolt 56 through a washer 57 into the third bolt hole 27 and the fourth bolt hole 32 which are aligned with each other.

[0044] In this way, the leg fixing jig 40 is constructed from separate components, a pair of leg materials 20 and an anchor plate 30, and the pair of leg materials 20 are first attached to the rising portion 11, and then the anchor plate 30 is joined to the pair of leg materials 20.This makes it possible to fix the leg materials 20 to the pair of side surfaces 12 of the rising portion 11 without any gaps, even if there are unevenness on the pair of side surfaces 12.

[0045] Furthermore, since the fourth bolt hole 32 of the anchor plate 30 is a long hole that is long in the width direction of the rising portion 11, it is possible to bolt the top plate 25 and the anchor plate 30 while adjusting the position of the first bolt hole 35, which is bolted to the leg plate 65 of the extension structure 60, in the width direction.

[0046] Furthermore, the method of fabricating a U-shaped leg fixing jig in advance and fitting it into the top end 13 of the raised portion 11 is not preferable because there are cases in which fitting is not possible or conversely, gaps will occur between the side surfaces 12 and the raised portion 11 due to unevenness, etc., as described above.

[0047] In the illustrated example, as shown in FIG. 3, two leg fixing jigs 40 are fixed to the rising portion 11 at an interval in the longitudinal direction of the slab 10 (this completes the process of forming the leg fixing jigs).

[0048] Next, as shown in Figures 4 and 5, the first bolt hole 35 of each anchor plate 30 of the two leg fixing jigs 40 is aligned with the second bolt hole 66 of the leg plate 65 of the expansion structure 60, and the anchor bolt 70, which is a double-ended bolt, is inserted (screwed in) to bolt the anchor plate 30 and the leg plate 65 together, and the leg fixing structure 80 of the expansion structure is constructed.

[0049] In this way, leg fixing structure 80 is not a conventional structure in which anchor bolts are driven into the rising portion to fix the leg plate of the extension structure to the rising portion, but rather a structure in which leg fixing jig 40 is fixed to rising portion 11, and anchor plate 30 and leg plate 65 that make up leg fixing jig 40 are fixed with anchor bolt 70, which is a new leg fixing structure not seen in the past (above is the process of bolting the leg plate to the anchor plate).

[0050] Here, by inserting the anchor bolt 70 into the first bolt hole 35 and the second bolt hole 66 which are aligned with each other without welding the anchor bolt 70 to the anchor plate 30 in advance, it is possible to prevent the anchor bolt 70 which has been welded in advance and protrudes upward from interfering with the installation of the additional structure 60.

[0051] As shown in the illustrated example, a leg plate 65 joined to two leg fixing jigs 40 fixed to the rising portion 11 supports the columns 60 of the load-bearing wall, which is the additional structure, thereby forming a stable leg fixing structure 80 with high fixing strength to the slab footing 10, thereby providing an excellent earthquake-resistant reinforcement structure for an existing building.

[0052] 3, when a horizontal force H acts on a column 60 of a bearing wall during an earthquake, a pull-out force P may act on one of the leg fixing jigs 40 due to the horizontal force H. This pull-out force P is resisted by a cone fracture surface CL having an angle θ of, for example, 45 degrees from the horizontal, starting from the lowest through-bolt 50. For this reason, the distance t from the top end 13 of the rising portion 11 to the lowest through-bolt 50 should be set to a length that can form a cone fracture surface CL having the area required for the design pull-out force.

[0053] In this way, instead of the conventional method of driving a general anchor bolt into the top end 13 of the rising portion 11, by fixing the leg material 20 of the leg fixing jig 40 to the side surface 12 of the rising portion 11, it is possible to prevent interference between the main reinforcement of the rising portion 11 and the anchor bolt 70, and it is possible to obtain a leg fixing structure 80 that can guarantee a cone breaking surface CL that can withstand the acting pull-out force P.

[0054] According to the leg fixing method for an extension structure shown in the figures and the leg fixing structure 80 constructed using this leg fixing method, it is possible to eliminate the need for chipping of the slab footing 10 and filling with concrete, and there is no risk of interference between the anchor bolts 70 that fix the leg plate 65 to the slab footing 10 and the main reinforcement of the rising portion 11, so that a leg fixing structure 80 can be constructed that is easy to construct and has high fixing strength to the slab footing 10.

[0055] In addition, the present invention is not limited to the configuration shown here, and may be implemented in other embodiments in which other components are combined with the configurations and the like of the above-mentioned embodiment. In this regard, the present invention may be modified within the scope of the gist of the present invention, and may be appropriately determined according to the application form. [Explanation of symbols]

[0056] 10:Strip foundation 11: Rising section 12: Side 13: Top edge 14: Bolt hole 15: Footing 20: Leg material 21: Shape steel material (channel steel) 22:Top 25: Top plate 27: 3rd bolt hole 30: Anchor plate 32: 4th bolt hole (long hole) 35: First bolt hole 40: Leg fixing jig 50:Through bolt 56: Fixing bolt 57: Washer 60: Additional structure (pillars of bearing walls) 65: Leg plate 66: 2nd bolt hole 70: Anchor bolt (double-ended bolt) 80: Leg fixing structure (leg fixing structure for additional structure) G: Ground CL: Cone breaking line (cone breaking surface)

Claims

1. A leg fixing structure for an extension structure in which a leg plate of an extension structure is fixed to a rising portion of an existing slab footing by an anchor bolt, A pair of legs are fixed to each of a pair of side surfaces of the rising portion, The upper portions of the pair of legs are connected to an anchor plate that spans the top end of the rising portion to form a leg fixing jig, A leg fixing structure for an extension structure, characterized in that a first bolt hole of the anchor plate and a second bolt hole of the leg plate are aligned, the anchor bolt is inserted, and the anchor plate and the leg plate are bolted together.

2. The leg member includes a shaped steel member and a top plate joined to a top portion of the shaped steel member, the top plate includes a third bolt hole, and the anchor plate further includes a fourth bolt hole separate from the first bolt hole; The leg fixing structure of the extension structure according to claim 1, characterized in that the third bolt hole and the fourth bolt hole are aligned and a fixing bolt is inserted through them to bolt the top plate and the anchor plate.

3. 3. The leg fixing structure for an extension structure according to claim 2, wherein the fourth bolt hole is an elongated hole that is long in a width direction of the rising portion.

4. 3. The leg fixing structure of an extension structure according to claim 2, characterized in that the shaped steel material is fixed to the rising portion by a plurality of through bolts or post-installed anchors spaced apart in the longitudinal direction.

5. 5. The leg fixing structure of an extension structure according to claim 1, wherein a plurality of leg fixing jigs are fixed to the rising portion in the longitudinal direction thereof, and a leg plate of the extension structure is fixed to the plurality of leg fixing jigs.

6. 2. The leg fixing structure for an extension structure according to claim 1, wherein the extension structure is a column forming a load-bearing wall that is added to an existing building by post-construction.

7. A method for fixing the legs of an extension structure by fixing the leg plate of the extension structure to the rising portion of an existing slab footing with an anchor bolt, a step of fixing a pair of legs to a pair of side surfaces of the rising portion, respectively; A step of connecting the upper parts of the pair of leg members with an anchor plate that spans the top end of the rising portion to form a leg fixing jig consisting of the pair of leg members and the anchor plate; a step of aligning a second bolt hole of the leg plate with a first bolt hole of the anchor plate, inserting the anchor bolt, and bolting the leg plate to the anchor plate.

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