JP2012122256A - Column leg fitting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a column leg fitting capable of suppressing variations in internal stress and tension load on an anchor bolt, for any variations in direction of horizontal load acting on a column.SOLUTION: A column leg fitting 10a comprises a lower plate 11 having a circular or polygonal shape having six sides or more to be placed on a foundation 31, an upper plate 17 to come in contact with the underside of a column 41, and a connection part including upright plates 14 to integrate the both plates 11 and 17. The lower plate 11 has fixing holes 12 for insertion of anchor bolts 32, the upper plate 17 has mounting holes 18 for insertion of bolts 49 or the like, and the upright plates 14 are arranged at equal angular intervals along radial directions extending from the center of the lower plate 11. The fixing holes 12 are also arranged at an equal distance from the center of the lower plate 11, at equal angular intervals. Consequently, when the lower plate 11 is tilted around a supporting point due to variations in horizontal load, the arrangement of the anchor bolts 32 or the like remains approximately constant viewed from the supporting point. The variations in load on the anchor bolts 32 are thus suppressed, resulting in reducing design work.

Description

  The present invention relates to a column base for mounting a wooden column on a concrete foundation.

  In wooden construction, a framework is constructed by combining rods such as pillars and beams, except for a wooden framework wall construction method called two-by-four. In the past, it was difficult to obtain large cross-section bars, and large wooden buildings were limited except for temples, etc., but in recent years technology development such as adhesives has progressed, and large cross-section laminated lumber has been manufactured without difficulty. I can do it now. For this reason, it becomes possible to make public facilities, stores, and the like wooden, and the natural atmosphere can give a good impression to users and the like.

  In many cases, a wooden structure using laminated wood with a large cross section employs a portal frame construction method in which bars are assembled in a gate shape and arranged at regular intervals, as in the conventional steel structure. The gate-shaped frame needs to firmly connect the base to the foundation in order to prevent lodging due to external force, and a column base hardware is often interposed between the upper surface of the foundation and the lower surface of the column. The column base metal is integrated with the foundation via an anchor bolt embedded in the foundation, and further integrated with the column via a bolt or the like, and even when an upward load is applied to the column, it is prevented from lifting.

  Various technical developments have been made on column base hardware, and examples thereof include the following patent documents. Document 1 discloses a column base structure in a wooden ramen frame, in which a foundation and a wooden column are connected using a column base support hardware. The column base support hardware is composed of a steel box placed on the upper surface of the foundation and a steel gusset plate inserted into a notch groove processed into a wooden column, and is anchored to the bottom plate of the steel box The wooden column is fixed to the foundation by inserting the bolt and inserting the bolt from the side of the wooden column toward the steel gusset plate. The present invention has an effect that the work of fixing the wooden pillar and the column base supporting hardware can be performed in the factory, and the amount of work at the construction site can be reduced.

  Document 2 discloses a column base structure in a wooden building and a metal fitting for the column base structure. A box-shaped column support is sandwiched between the base and the wooden column, and a rod-shaped column coupling holding metal is embedded in the wooden column. The column connection holding bracket is integrated with the top plate of the column support base with bolts. However, if a large amount of force is applied due to earthquake shaking, etc., a disc spring is incorporated to ensure flexibility. However, sufficient strength can be maintained.

  Document 3 discloses a column base for a column base, and Document 4 discloses an exposed steel column base. Both are technologies for installing a steel column on foundation concrete, and a flange-like base plate is attached to the lower end surface of the steel column. In such a structure, when a bending moment acts on the steel column, the base plate behaves like a toe standing. At that time, there is a risk that the load concentrates on a position that becomes a fulcrum of standing on the tip of the toe and destroys the foundation concrete. In order to solve this problem, in Literature 3, an inclined surface is formed on the outer edge of the lower surface of the base plate, and the contact area when standing on the toe is increased to prevent the foundation concrete from being destroyed. Further, in Document 4, by optimizing the design around the base plate, the base plate is deformed at an early stage to prevent toes from standing.

JP 2001-107456 A JP 2008-163652 A JP 2000-008493 A JP 2005-016212 A

  FIG. 7 shows a state in which a column is mounted on a foundation using a common column base hardware. The column was made of wood with a square cross section, and the column base was composed of a lower plate that contacted the upper surface of the foundation, an upper plate that contacted the lower surface of the column, and an upright plate that connected the lower and upper plates. H shape. Both the lower plate and the upper plate have the same size as the cross section of the column, the lower plate is integrated with the foundation via an anchor bolt, and the upper plate is integrated with the column via a bolt. A lag screw is screwed into the lower surface of the column, and a female screw for screwing a bolt is provided at the lower end thereof.

  This column may receive a horizontal load from the side of the column, such as load A in the figure due to strong winds or earthquakes, etc., and a horizontal load from the corner direction of the column, such as load B in the diagram. There is also. When such a horizontal load is received, the lower plate behaves like a toe as shown in the literature 3 and the literature 4, but the four anchor bolts suppress this.

  FIG. 8 shows a longitudinal section of FIG. 7, and the upper part is an AA section when receiving a load A, and the lower part is a BB section when receiving a load B. Since the cross section of the column is square, the column of the BB section is about 1.4 times wider than the AA section. In the AA sectional view, the column tends to fall to the left side due to the load A. Therefore, the lower plate tries to stand on the toe with the left end side as a fulcrum. Moreover, in the BB sectional view, the column tends to fall to the left side by the load B. Therefore, the lower plate tries to stand on the toe with the left corner as a fulcrum.

  Thus, when the pillar receives a horizontal load, the anchor plate suppresses the toe standing of the lower plate. However, the distance D from the fulcrum to each anchor bolt is greatly different between the AA sectional view and the BB sectional view, and even if the load A and the load B are the same size, The stress generated and the tensile load generated on the anchor bolt are greatly different between the two sectional views. Therefore, when designing a structure using column base hardware as shown in Fig. 7, it is necessary to calculate the strength each time by changing the direction of the horizontal load little by little, which is problematic in terms of labor, time and accuracy. There is. In order to solve this problem, measures such as increasing the size of the column base hardware can be considered, but an increase in the manufacturing cost and problems due to an increase in occupied space are expected, which is not realistic.

  The present invention was developed on the basis of such a situation, and a column base metal that can suppress changes in internal stress and tensile load generated in an anchor bolt regardless of how the horizontal load acting on the column changes. The purpose is to provide.

  The invention according to claim 1 for solving the above-mentioned problems is a circular or hexagonal or more polygonal lower plate contacting the upper surface of the foundation, and contacting the lower surface of the column located directly above the lower plate. And a connecting portion that extends in the vertical direction and is fixed to the lower plate and the upper plate. The lower plate has six fixing holes for fastening to the foundation via anchor bolts. The upper plate is provided with a plurality of mounting holes for fastening to the pillars via bolts or the like, and the fixing holes are arranged at an equal distance and an equal angle from the center of the lower plate. It is a column base hardware.

  The present invention is a column pedestal for interposing between the upper surface of the foundation and the lower surface of the column to install the column on the foundation, and the column is premised on being made of wood containing laminated timber, The cross section is a square or a rectangular shape similar to a square. Moreover, the foundation is a wall-like shape in which concrete is cast, and anchor bolts protrude from the upper surface.

  The column base is composed of a lower plate, an upper plate, and a connection part. The lower plate and the upper plate are made by cutting a steel plate into a predetermined shape, and the connection part is also made of steel, and the whole is welded at the manufacturing stage. Integrate with. The lower plate is in contact with the upper surface of the foundation, but the shape thereof is not a conventional rectangular shape, but is a circular shape or a hexagonal or more polygonal shape. If a polygon is used, it is not limited to a regular polygon in which the lengths and intersection angles of each side are equal, and some degree of deviation may occur. Further, the lower plate is provided with six or more fixing holes for inserting anchor bolts so that it can be integrated with the foundation. Note that all the fixing holes are arranged at equal angles on a concentric circle as viewed from the center of the lower plate.

  The upper plate contacts the lower surface of the column and receives the load transmitted from the column. Therefore, the upper plate has substantially the same shape as the cross section of the column. The upper plate and the pillar need to be integrated by some means, but a simple flat-headed nail has problems in strength and durability, and at least a large screw nail is used. Furthermore, when it is desired to integrate the upper plate and the column securely, a lag screw is screwed into the lower surface of the column, and a bolt is inserted from the upper plate toward the lag screw. A lag screw is formed by forming spiral ridges on the side surface of a cylindrical steel material, and forming female threads on the end face. The ridges bite into the columns, so they are firmly integrated with the columns. To do. The upper plate is provided with a plurality of mounting holes for inserting screw nails and bolts.

  The connecting portion is for securing a space between the lower plate and the upper plate to secure a space for inserting a bolt, a nut, or the like, and is arranged so as to stand upright with respect to the lower plate or the upper plate. It is assumed that the lower plate and the upper plate are arranged in parallel, and the centers of both plates are coincident. The connecting portion is made of steel in order to be integrated with the lower plate and the upper plate by welding, but the specific shape is free. However, it should be symmetrical when viewed from above in order not to hinder the installation of bolts and nuts, to have sufficient strength against various loads, and to eliminate the influence of changes in the direction of horizontal load. preferable.

  In this way, the upper plate has a square shape corresponding to the cross section of the column, but the lower plate has a circular or polygonal shape. The received load is almost constant regardless of the horizontal load direction. This is because the positional relationship between the fulcrum and the anchor bolt at the time of standing on the tip of the toe becomes almost constant regardless of the direction of the horizontal load by arranging the fixing holes at six or more positions at equal angles. As a result, the strength calculation around the column base hardware can be simplified at the time of design. Naturally, as the number of fixing holes is increased, the change in the load received by the anchor bolt or the like is reduced and approaches an ideal state.

  The invention according to claim 2 is a specific example of the connecting portion, and the connecting portion is composed of six or more upright plates, and the upright plates are arranged at equal angles along the radiation extending from the center of the lower plate. Features. There is no problem even if the upright plate has a simple rectangular shape, and at least six plates are used to ensure balance, and the upright plates are arranged at equal angles along the radiation extending from the center of the lower plate. Therefore, when eight upright plates are used, the interval is 45 degrees. In order to prevent interference between the adjacent upright plates, the upright plate reaches the vicinity of the outer edge of the lower plate with a position at a certain distance from the center of the lower plate as a base point. In addition, at least one fixing hole is provided between adjacent upright plates.

  The invention according to claim 3 is also a specific example of the connecting portion, and the connecting portion extends in the vertical direction and is fixed to the center portion of both the lower plate and the upper plate, and the upright plate according to claim 2 The upright plate is arranged on the outer peripheral side of the central axis. As the upright plates adjacent to each other approach each other toward the center of the lower plate, the upright plate cannot be disposed at the center of the lower plate. However, when a heavy load is applied to the column base metal, the center axis can be provided as in the present invention to reduce the burden on the upright plate. The central axis is preferably circular so that it is not affected by changes in the direction of horizontal load, and may be hollow for further weight reduction. In addition, although an upright board is arrange | positioned on the outer peripheral side of a center axis | shaft, both may not be integrated by welding.

  As in the first aspect of the invention, the bottom plate of the column base metal is circular or polygonal, and the fixing holes at six or more locations are arranged at equal angles from the center of the bottom plate at equal angles. Even when the direction of the horizontal load applied to the base plate changes, the anchor bolt placement and distance to the anchor plate are almost constant when viewed from the fulcrum when the lower plate stands on the tip of the toe. The load conditions to be applied are almost constant. Therefore, at the time of design, it is not necessary to change the direction of the horizontal load little by little as in the past, and it is not necessary to calculate the strength each time, and it is only necessary to perform the strength calculation assuming only the horizontal load from one direction. Can be reduced.

  As in the invention of claim 2, by disposing six or more upright plates radially, the load acting on the column base metal can be dispersed over a wide range to reduce the load on the welded part, The improvement of rigidity can also be expected. Furthermore, the load transmission path from the mounting hole to the fixing hole is shortened, and the bending moment acting on the lower plate and the upper plate is reduced, and these deformations can be suppressed.

  As in the invention described in claim 3, by providing a central axis that connects the center portions of the lower plate and the upper plate, it is possible to improve the strength of a place where it is difficult to arrange the upright plate, and it is suitable for a place where load conditions are severe Column base hardware is realized. The central axis is disposed at the center of the column base metal, and the rigidity does not change even when the direction of the horizontal load changes.

It is a perspective view which shows the example of a shape of the column base metal object by this invention, and its use condition. It is a perspective view which shows the manufacturing process of the column base metal fitting of FIG. 1, and the state which actually installed the pillar. It is a perspective view which shows the column base metal object which integrated the lower board and the upper board with the cylindrical tube. It is a perspective view which shows the column base metal object which used the lower plate as a hexagon and also used six upright plates. It is a perspective view which shows the column base metal object assumed to install the pillar of a large cross section. It is a perspective view which shows the manufacturing process of the column base metal fitting of FIG. 5, and the state which actually installed the pillar. It is a perspective view which shows the state installed on the foundation using the common column base metal fitting. FIG. 8 shows a longitudinal section of FIG. 7, wherein the upper part is an AA sectional view when a load A is received, and the lower part is a BB sectional view when a load B is received.

  FIG. 1 shows an example of the shape of a column base 10a according to the present invention and its use state. The column base 10 a is sandwiched between the foundation 31 and the column 41 and is used to install the column 41 on the foundation 31, and includes a lower plate 11, an upright plate 14, and an upper plate 17. The lower plate 11, the upright plate 14 and the upper plate 17 are obtained by cutting steel plates into a predetermined shape and integrated by welding at the manufacturing stage. ing. The column 41 is made of wood and has a square cross section. The foundation 31 is made by placing concrete in a wall shape, and the upper surface is finished horizontally.

  The lower plate 11 is a simple circle placed on the upper surface of the foundation 31, but its diameter is equal to the length of one side of the cross section of the column 41. Therefore, when the pillar 41 is looked down from directly above, the lower plate 11 is hidden by the pillar 41 and cannot be visually recognized. Furthermore, eight fixing holes 12 are provided in the lower plate 11. All the fixing holes 12 are arranged concentrically and at equal angles (45 degrees in this figure). Note that eight anchor bolts 32 protrude from the upper surface of the base 31 corresponding to the fixing holes 12. After the anchor bolt 32 is inserted into the fixing hole 12 and the lower plate 11 is brought into contact with the upper surface of the foundation 31, when the nut 33 is screwed and tightened to the tip of the anchor bolt 32, the lower plate 11 is attached to the foundation 31. Integrate.

  The upper plate 17 contacts the lower surface of the column 41. Therefore, it is the same size as the cross section of the column 41. Further, in order to integrate the upper plate 17 with the column 41, a lag screw 45 is screwed into the lower surface of the column 41. The lag screw 45 is a columnar steel material, and is formed with a ridge 46 that protrudes from the side peripheral surface and extends spirally. When the ridge 46 bites into the column 41, a load can be transmitted through the entire ridge 46, and the occurrence of cracks and the like can be suppressed. The lower portion of the lag screw 45 has a hexagonal shape for hooking a tool, and a female screw 47 for screwing a bolt 49 is provided at the center of the lower end surface.

  In order to screw the lag screw 45 into the lower surface of the column 41, pilot holes 42 are machined at the four corners. The upper plate 17 is provided with a mounting hole 18 concentric with the lower hole 42. Therefore, after screwing the lag screw 45 into the lower hole 42, the upper plate 17 is brought into contact with the lower surface of the column 41, and a bolt 49 is inserted from below the mounting hole 18 and screwed into the female screw 47 and tightened. The upper plate 17 is integrated with the column 41.

  The upright plate 14 is a connecting portion for integrating the lower plate 11 and the upper plate 17 and uses eight pieces having the same shape, and a space for attaching the nut 33 and the bolt 49 is secured. The individual upright plates 14 have a slightly vertically long rectangular shape and are arranged at equal angles on the radiation extending from the center of the lower plate 11. Note that the upright plate 14 reaches almost the outer edge of the lower plate 11 with a base point at a position slightly away from the center in consideration of the density near the center of the lower plate 11.

  FIG. 2 shows a manufacturing process of the column base 10a of FIG. 1 and a state where the column 41 is actually installed. When manufacturing the column base 10a, the lower plate 11, the upright plate 14, and the upper plate 17 are cut out, the fixing holes 12 and the mounting holes 18 are processed, and these are integrated by welding. In the upper left figure, the upright plate 14 is attached to the lower plate 11, but the fixing hole 12 is located in the middle of the two adjacent upright plates 14, and the nut 33 can be tightened without any trouble. . Further, as shown in the upper right figure, the completed column base 10 a has the center of the lower plate 11 and the center of the upper plate 17, and the corner of the upper plate 17 protrudes from the outer edge of the lower plate 11. Yes. In addition, the attachment holes 18 are located in the middle of the two adjacent upright plates 14, but the number thereof is half that of the fixed holes 12.

  The lower plate 11 of the column base 10a has a circular shape, and the anchor bolts 32 are arranged at an equal angle and at a narrow interval, as shown in the lower “in the state where the column is installed on the foundation”. Therefore, no matter how the direction of the horizontal load acting on the column 41 changes, the arrangement of the anchor bolts 32 and the distance to the anchor plate 32 do not change greatly as seen from the fulcrum when the lower plate 11 stands on the toes. . Because of this property, when calculating the strength of the structure using the column base 10a, it is only necessary to assume a horizontal load from one direction, and as usual, assume a horizontal load from various directions. There is no need, and the design effort can be reduced. If there is a margin around the base 31, the diameter of the lower plate 11 can be increased to further improve the stability.

  FIG. 3 shows a column base 10 b in which the lower plate 11 and the upper plate 17 are integrated by a cylindrical tube 22. In FIG. 1, the upright plate 14 is used as a connecting portion for integrating the lower plate 11 and the upper plate 17, but the connecting portion may be a cylindrical tube 22 as shown in this figure. The cylindrical tube 22 is obtained by simply cutting out a steel pipe, which is attached to the lower plate 11 and the upper plate 17 by welding, and since there are few welded portions, the cost can be easily reduced. However, this configuration is difficult to ensure the rigidity against the load in the horizontal direction, so it is used in places where the load conditions are loose. If a certain degree of rigidity is required, ribs (not shown) can be attached to the outer periphery of the cylindrical tube 22.

  FIG. 4 shows a column base 10c in which the lower plate 11 has a hexagonal shape and six upright plates 14 are used. The lower plate 11 is ideally circular as shown in FIG. 1, but may be polygonal as shown in this figure for reasons of manufacturing, balance with surrounding structures, and the like. However, the pentagonal shape has a small difference from a normal rectangle, and there is a possibility that the effect of the present invention can hardly be exhibited. The lower plate 11 in this figure is a regular hexagon in which the length of each side is equal to the angle of intersection between adjacent sides, and a fixing hole 12 is provided in the vicinity of each vertex of the lower plate 11.

  The upright plates 14 are arranged at the same angle as the number of corners of the lower plate 11 and are alternately arranged with the fixing holes 12. Further, the upper plate 17 is the same square as in FIG. 1, and the lower plate 11 and the upper plate 17 are integrated through the upright plate 14 with the centers aligned. Of the total four mounting holes 18, two (two on the left and right in the figure) are located on the extension line of the upright plate 14, but the corner of the upper plate 17 is located on the lower plate 11. It protrudes from the outer edge, and the bolt 49 can be inserted without hindrance.

  After the column 41 is installed using the column base 10c, a horizontal load acts on the column 41, and when the lower plate 11 stands on the toe, its fulcrum is at the side of the lower plate 11 and at the apex. There is a case. For this reason, it is inevitable that the load acting on each anchor bolt 32 also changes due to the change in the direction of the horizontal load. However, this change can be suppressed as compared with a normal rectangular shape, and has little practical effect. In addition, this point is eliminated by increasing the number of corners of the lower plate 11.

  In this figure, the lower plate 11 is hexagonal and the upright plates 14 are six. However, it is not necessary to match the two, for example, the lower plate 11 is a regular dodecagon and the upright plates 14 are six. You can choose freely. Further, the connecting portion may be a cylindrical tube 22 as shown in FIG. Thus, the lower plate 11, the upper plate 17, and the connecting portion can be freely combined, but the overall balance and workability should be taken into consideration. In addition, even when the lower plate 11 is a polygon, it is not necessary to force a regular polygon, and a certain amount of error may occur.

  FIG. 5 shows a column base 10d that assumes that a column 41 having a large cross section is installed. The column 41 having a large cross section has a large vertical load to be applied, and in order to cope with this, it is necessary to increase the number of upright plates 14 (sixteen in this figure). However, in the central part of the lower plate 11 where the upright plate 14 is concentrated at one point, the arrangement is difficult, and the central shaft 25 is arranged as a substitute for the upright plate 14. The central shaft 25 is obtained by cutting a steel pipe, and its upper and lower ends are integrated with the lower plate 11 and the upper plate 17 by welding. In addition, the lower plate 11 has a circular shape similar to that shown in FIG. 1 and the like, and the fixing holes 12 are arranged at sixteen equiangular positions. On the other hand, the upper plate 17 is square, but has eight mounting holes 18 in order to ensure strength.

  FIG. 6 shows a manufacturing process of the column base 10d of FIG. 5 and a state where the column 41 is actually installed. As shown in the upper drawing, the fixing hole 12 is located in the middle of two adjacent upright plates 14, and the fixing hole 12 and the upright plate 14 are relatively close to each other. Therefore, even when a load is applied in a direction in which the lower plate 11 and the upper plate 17 are separated from each other, the bending moment acting on both the plates 11 and 17 does not become excessive, and these deformations can be suppressed. In addition, although the outer peripheral surface of the central shaft 25 is in contact with the end surface of the upright plate 14, welding is omitted due to work space constraints.

  When the column 41 is installed using the column base 10d, the anchor bolts 32 are continuously arranged at a narrow interval as shown in the lower figure, and how the direction of the horizontal load received by the column 41 changes. Even in this case, there is no significant change in the arrangement of the anchor bolts 32 as seen from the fulcrum when the lower plate 11 stands on the toes. Therefore, when designing a structure using the column base 10d, it is not necessary to repeat the strength calculation by changing the direction of the horizontal load.

10a, 10b, 10c, 10d Column base 11 Lower plate 12 Fixing hole 14 Upright plate (connection part)
17 Upper plate 18 Mounting hole 22 Cylindrical tube (connection part)
25 Central axis (connection part)
31 foundation 32 anchor bolt 33 nut 41 pillar 42 pilot hole 45 lag screw 46 ridge 47 female screw 49 bolt

Claims (3)

A circular or hexagonal or lower polygonal lower plate (11) that contacts the upper surface of the foundation (31), and an upper plate that is located directly above the lower plate (11) and contacts the lower surface of the column (41) 17) and connecting portions (14, 22, 25) that extend in the vertical direction and are fixed to the lower plate (11) and the upper plate (17),
Consists of
The lower plate (11) is provided with six or more fixing holes (12) for fastening to the foundation (31) via anchor bolts (32),
The upper plate (17) is provided with a plurality of mounting holes (18) for fastening to the pillar (41) via bolts (49) or the like,
The column base metal, wherein the fixing holes (12) are arranged at an equal distance and an equal angle from the center of the lower plate (11).   The said connection part consists of six or more upright boards (14), and this upright board (14) is located in a line at equal angles along the radiation extended from the center of the said lower board (11). Column base hardware according to 1. The connecting portion includes a central axis (25) that extends in the vertical direction and is fixed to the central portions of both the lower plate (11) and the upper plate (17), and the upright plate (14). The column base metal according to claim 2, wherein the upright plate (14) is arranged on an outer peripheral side of the central axis (25).

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