Joining structure and method between existing foundation and new column

Abstract

To provide a joining structure and method for joining an existing reinforced concrete foundation to a new column that eliminates the need for extensive work such as chipping, which generates noise, and anchor bolt installation, while enabling a high-strength joining of the existing foundation and the new column. [Solution] This is a joint structure 100 for an existing foundation and a new column, in which a new column 20 is joined to an existing reinforced concrete foundation 10. The column base 22 of the new column 20 is placed on the top surface 14 of the rising section 11 of the existing foundation 10, and a pair of steel plates 30 are arranged so as to straddle the opposing side surfaces 12 of the rising section 11 and the column base 22, and the steel plates 30 and the column base 22 are joined together, and adhesive 60 is filled into the gap S between the side surfaces 12 of the rising section 11 and the steel plates 30.

Description

Technical Field

[0001] The present invention relates to a joining structure and a joining method between an existing foundation and a newly installed column.

Background Art

[0002] When reforming or seismic strengthening an existing building such as a house, there may be a case where a newly installed column is joined to an existing reinforced concrete foundation for addition. When constructing this newly installed column, among the top ends of the existing reinforced concrete foundation, a recess extending downward is constructed by cutting the concrete at the installation position of the newly installed column, and after arranging a part of an anchor bolt in the recess, the so-called leveling is performed by filling the recess with mortar or concrete such as high-strength mortar.

[0003] An anchor bolt protruding upward from the top end of the existing foundation is inserted into bolt holes provided in a column base plate or column base metal fittings, etc. at the column base of the newly installed column composed of a steel column or the like, so that the leveled existing foundation and the newly installed column are joined.

[0004] The above leveling work includes operations such as cutting the existing foundation and filling mortar or concrete into the constructed recess, and generally involves large-scale work. Therefore, it is inevitable that it will cause some interference to the daily life of the occupants living in the existing building to be constructed. In addition to affecting the daily life of the occupants, the noise during the cutting work of the existing foundation and the like can also be a cause of complaints from the neighborhood.

[0005] From the above, when joining a newly installed column to an existing reinforced concrete foundation, it is desirable to have a joining structure and a joining method between the existing foundation and the newly installed column that can join the existing foundation and the newly installed column with high joining strength while eliminating large-scale leveling work including cutting work that causes noise and installation of anchor bolts.

[0006] Here, Patent Document 1 proposes a method for installing anchor bolts. This installation method is for installing anchor bolts to an existing reinforced concrete foundation having a rising section, and comprises the steps of: drilling vertical and horizontal holes that communicate with each other within the rising section from the top and side surfaces of the rising section; embedding a plug anchor in the top surface of the rising section; holding the upper part of the anchor bolt with an anchor bolt holder installed on the rising section and letting the anchor bolt hang down into the vertical hole; inserting a screw into a screw insertion hole formed in the anchor bolt holder and screwing it into the plug anchor to fix the anchor bolt holder; screwing a fixing member having a first nut into the lower end of the anchor bolt hanging down into the horizontal hole and filling the horizontal and vertical holes with a filler material; and removing the anchor bolt holder and screw after the filler material has hardened. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2013-249699 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] Although the anchor bolt installation method described in Patent Document 1 is said to reduce the management effort required in post-installation work, this installation method also involves drilling vertical and horizontal holes from the top and side surfaces of the rising section of the reinforced concrete foundation, and therefore inherently contains the above-mentioned problems caused by the chipping work of the existing foundation.

[0009] This invention has been made in view of the above problems, and aims to provide a joining structure and joining method for an existing foundation and a new column that can join an existing reinforced concrete foundation and a new column with high joining strength, while eliminating the need for extensive work such as chipping work, which is a source of noise, and anchor bolt installation, when joining a new column to an existing reinforced concrete foundation. [Means for solving the problem]

[0010] To achieve the above objective, one embodiment of the joining structure between an existing foundation and a newly installed column according to the present invention is: A connection structure between an existing foundation and a new column, in which a new column is joined to an existing reinforced concrete foundation, The base of the new column is placed on the top of the rising section of the existing foundation. A pair of steel plates are arranged so as to straddle the opposing sides of the rising portion and the column base, the steel plates and the column base are joined together, and adhesive is filled into the gap between the sides of the rising portion and the steel plates.

[0011] According to this embodiment, a pair of steel plates are arranged so as to straddle the opposing sides of the rising section of the existing reinforced concrete foundation and the column base, the steel plates and the column base are joined together, and adhesive is filled in the gap between the sides of the rising section and the steel plates. This makes it possible to join the rising section of the existing foundation and the new column with high joint strength, while eliminating the need for chipping work on the rising section and the installation of anchor bolts, which are sources of noise when installing a new column.

[0012] Here, the existing foundation includes strip foundations and raft foundations that have a rising section, and the rising section has at least a pair of sides and a top surface on which the base of the newly installed column is placed.

[0013] The gap between the side of the rising section and the steel plate may be, for example, 1 mm to several mm wide. By filling this narrow gap with adhesive, the side of the reinforced concrete rising section and the steel plate are joined with high strength.

[0014] Furthermore, other embodiments of the joint structure between the existing foundation and the newly installed column according to the present invention are: The side surface of the rising portion and the steel plate are joined to each other by a first fastener extending laterally, in a position that secures the gap. The newly installed column is a steel column, and the column base and the steel plate are joined to each other by a second fastener that extends laterally.

[0015] According to this embodiment, the side surface of the rising section and the steel plate are joined to each other by a first fastener extending laterally, while a gap is secured between them. The base of the newly installed column and the steel plate are joined to each other by a second fastener extending laterally. As a result, the base of the newly installed column and the steel plate are joined with high strength while a predetermined gap for filling with adhesive is secured.

[0016] Furthermore, other embodiments of the joint structure between the existing foundation and the newly installed column according to the present invention are: The first fastener is characterized in that it penetrates the rising portion laterally and connects the pair of steel plates.

[0017] According to this embodiment, since the first fastener penetrates the rising section laterally and connects the pair of steel plates, when an uplift force acts on the base of the newly installed column, the tensile resistance force transmitted through the second fastener, the steel plates, and the adhesive resists the uplift force. In addition, the bearing resistance force of the first fastener penetrating the rising section also resists the uplift force, thereby improving the uplift resistance.

[0018] Furthermore, other embodiments of the joint structure between the existing foundation and the newly installed column according to the present invention are: The invention is characterized in that at least the side surface of the steel plate facing the adhesive is provided with a convex portion and / or a concave portion.

[0019] According to this embodiment, by providing convex and / or concave portions on at least the side surface of the steel plate facing the adhesive, the bonding area between the steel plate and the adhesive can be increased, thereby increasing the bonding strength between the steel plate and the side surface of the rising portion.

[0020] Here, "protrusions and / or recesses are provided on at least the side surface of the steel plate facing the adhesive" means that in addition to the form in which protrusions or recesses are provided only on the side surface of the steel plate facing the adhesive, it includes the form in which protrusions or recesses are provided on both the side surface of the steel plate and the side surface of the rising part.

[0021] For example, by performing punching (or dowel boring) or the like on the steel plate, protrusions or recesses can be provided on the steel plate. On the other hand, when providing, for example, recesses on the side surface of the rising part made of reinforced concrete, it is desirable to roughen the side surface to such an extent that there is no influence of noise.

[0022] Another aspect of the joint structure of the existing foundation and the new column according to the present invention is On the side surface of the rising part, a strip-shaped sealing material is disposed along the outer contour of the steel plate, and the adhesive is filled in the gap inside the sealing material.

[0023] According to this aspect, by disposing a strip-shaped sealing material along the outer contour of the steel plate on the side surface of the rising part, it is possible to prevent the leakage of the adhesive filled in the gap inside the sealing material. Here, the sealing material includes a liquid sealing material and a dry sealing material. In the case of a liquid sealing material, a construction is performed in which the sealing material is filled in a strip shape on the side surface of the rising part along the outer contour of the steel plate. In the case of a dry sealing material, a construction is performed in which a strip-shaped sealing material is adhered or the like to the side surface of the rising part along the outer contour of the steel plate.

[0024] One aspect of the method for joining an existing foundation and a new column according to the present invention is A method for joining an existing foundation and a new column, which joins a new column to an existing foundation made of reinforced concrete, A column placing step of placing the column base of the new column on the top end of the rising part provided in the existing foundation, The invention is characterized by a joining step comprising: arranging a pair of steel plates so as to straddle the opposing sides of the rising portion and the column base; joining the steel plates to the column base; and filling the gap between the sides of the rising portion and the steel plates with adhesive to join the steel plates to the rising portion.

[0025] According to this embodiment, a pair of steel plates are arranged so as to straddle the opposing sides of the rising section of the existing reinforced concrete foundation and the column base, the steel plates and the column base are joined, and adhesive is filled into the gap between the sides of the rising section and the steel plates to join them together. This makes it possible to join the rising section of the existing foundation and the new column with high joint strength, while eliminating the need for chipping work on the rising section and the installation of anchor bolts, which are sources of noise when installing a new column.

[0026] Furthermore, in another embodiment of the method for joining an existing foundation and a newly installed column according to the present invention, The steel plate has a plurality of filling holes spaced apart in the vertical direction. The bonding process is characterized by filling the lower filling hole with adhesive, confirming that the adhesive has overflowed from a separate filling hole located above it, and then filling the separate filling hole with adhesive.

[0027] According to this embodiment, by providing multiple filling holes in the steel plate at intervals in the vertical direction, filling the lower filling holes with adhesive, and after confirming that the adhesive has overflowed from a separate filling hole above, filling the adhesive from this separate filling hole can be used to suppress the occurrence of areas in the gap between the side surface of the rising portion and the steel plate that are not filled with adhesive, thereby forming a joint structure with high joint strength in which the entire gap is filled with adhesive.

[0028] Here, two or more filling holes can be provided at intervals in the vertical direction, and the filling of the adhesive can be completed by confirming that the adhesive filled from the uppermost filling hole has overflowed upward, for example, from the top edge of the steel plate. [Effects of the Invention]

[0029] As can be understood from the above explanation, the existing foundation and new column joining structure and joining method of the present invention make it possible to join an existing reinforced concrete foundation to a new column with high joining strength, while eliminating the need for extensive base adjustment work, including chipping work which causes noise and the installation of anchor bolts. [Brief explanation of the drawing]

[0030] [Figure 1A] This is a process diagram illustrating an example of a method for joining an existing foundation to a newly constructed column according to the embodiment. [Figure 1B] This is a view from arrow BB in Figure 1A. [Figure 2A] Following Figure 1A, this is a process diagram illustrating an example of a method for joining an existing foundation to a newly installed column according to the embodiment. [Figure 2B] This is a view from arrow BB in Figure 2A. [Figure 3] Following Figure 2A, this is a process diagram illustrating an example of a method for joining an existing foundation to a newly installed column according to the embodiment. [Figure 4] Following Figure 3, this is a process diagram of an example of a method for joining an existing foundation and a new column according to the embodiment, and also a diagram showing an example of a joining structure between an existing foundation and a new column according to the embodiment. [Figure 5] This figure shows another example of the connection structure between the existing foundation and the newly installed column according to the embodiment. [Modes for carrying out the invention]

[0031] Hereinafter, an example of the joint structure and joining method between the existing foundation and the newly installed column according to the embodiment will be described with reference to the attached drawings. In this specification and drawings, substantially identical components may be denoted by the same reference numerals to avoid redundant explanations.

[0032] [Joining structure and joining method between existing foundation and new column according to the embodiment] Referring to Figures 1 to 5, an example of the joining structure and joining method between an existing foundation and a new column according to the embodiment will be described. Here, Figures 1A, 2A, 3, and 4 are, in order, process diagrams of the joining method between an existing foundation and a new column according to the embodiment, and Figure 4 further shows an example of the joining structure between an existing foundation and a new column according to the embodiment.

[0033] In the following diagrams, only a portion of the existing strip foundation will be shown for explanation. The diagrams of existing columns and other structures erected on top of the existing foundation will be omitted, as will the diagrams of reinforcing bars embedded in the existing foundation.

[0034] The joining method according to this embodiment is a method for joining a new column 20 to an existing foundation 10 when renovating or seismically reinforcing a building such as a house.

[0035] The existing foundation 10 shown in Figures 1A and 1B is a reinforced concrete strip foundation having a rising section 11 with a pair of side surfaces 12 and a top surface 14, and a footing 15 placed on the ground G. Here, the existing foundation may be a raft foundation or the like with rising sections instead of a strip foundation. Also, crushed stone or lean concrete (not shown) is laid on the ground G, and the footing 15 is placed on top of these.

[0036] On the other hand, the newly constructed column 20 is a steel column made of shaped steel materials such as square steel pipes and H-shaped steel, and a column base block 22 is attached to the base of the column in the illustrated example.

[0037] The column base 22 of the new column 20, which is suspended by heavy machinery such as a crane (not shown), is placed on the column addition position at the top surface 14 of the rising section 11 of the existing foundation 10 (column placement process).

[0038] Next, as shown in Figures 2A and 2B, fastener holes 18 are installed at predetermined positions on the side surfaces 12 of the rising portion 11 of the existing foundation 10, extending to a point midway through the thickness of the rising portion 11. In the illustrated example, two fastener holes 18 (a total of four) are installed on the left and right sides of each pair of side surfaces 12 at a lower position close to the footing 15.

[0039] Here, the fastening holes 18 may be installed before the new column 20 is placed on the top surface 14 of the rising section 11. Also, the number of fastening holes 18 may be one or three or more, in addition to the illustrated example.

[0040] After fastening holes 18 are made in a pair of side surfaces 12, a pair of steel plates 30 are positioned so as to straddle each side surface 12 and the column base 22. The lower fastening holes (not shown) of the steel plates 30 are aligned with the fastening holes 18 in the side surfaces 12, and the first fastener 40A is inserted through the connecting fastening holes to fasten them. Furthermore, the upper fastening holes (not shown) of the steel plates 30 are aligned with fastening holes (not shown) made in the column base 22, and the second fastener 40B is inserted through the connecting fastening holes to fasten them, thereby joining the pair of side surfaces 12 of the rising section 11 and the pair of steel plates 30 that straddle the left and right sides of the column base 22.

[0041] Here, the first fastener 40A and the second fastener 40B can be fitted with hole-in anchors or bolts (including lag screw bolts), etc.

[0042] Furthermore, the steel plate 30 is provided with multiple (three in the illustrated example) filling holes 32A, 32B, and 32C spaced apart in the vertical direction.

[0043] As shown in Figure 2B, the steel plate 30 is joined to both the side surface 12 and the column base 22 in such a position that a small gap S of about 1 mm to several mm in width is secured between the side surface 12 of the rising section 11 and the steel plate 30.

[0044] Next, as shown in Figure 3, a strip-shaped sealant 50 is placed along the outer edge of the steel plate 30 on the side surface 12 of the rising portion 11, thereby closing the gap S along the outer edge of the steel plate 30. The strip-shaped sealant 50 is applied by filling with liquid sealant or by bonding a strip-shaped dry sealant, in a U-shape that opens upwards along the perimeter of the rectangular steel plate 30 in plan view.

[0045] Here, liquid sealants such as polyurethane-based sealants, acrylic-based sealants, acrylic-urethane-based sealants, and polysulfide-based sealants can be used. On the other hand, dry sealants such as ethylene propylene rubber (EPDM), butyl rubber, urethane rubber, and nitrile rubber can be used.

[0046] On the side surface 12 of the rising portion 11, a strip-shaped sealing material 50 is placed along the outer edge of the steel plate 30, and after closing the gap S on the outer edge, adhesive 60 is filled into the gap S inside the strip-shaped sealing material 50.

[0047] The adhesive 60 is filled in order from the lower filling hole 32A, filling the filling hole 32A with adhesive 60 and confirming that the adhesive 60 overflows from the filling hole 32B above it. Next, the adhesive 60 is filled in the filling hole 32B and it is confirmed that the adhesive 60 overflows from the filling hole 32C above it. Finally, the adhesive 60 is filled in the filling hole 32C and it is confirmed that the adhesive 60 overflows from above the gap S. In this way, the adhesive 60 is evenly filled throughout the entire gap S inside the strip-shaped sealing material 50, and the side surface 12 of the rising portion 11 and the steel plate 30 are joined via the adhesive 60 filled in the gap S, forming the joint structure 100.

[0048] In other words, the side surface 12 of the rising portion 11 and the steel plate 30 are joined to each other by both the first fastener 40A and the adhesive 60.

[0049] Here, adhesive 60 can be vinyl acetate resin adhesive, acrylic resin adhesive, urethane resin adhesive, epoxy resin adhesive, polyamide adhesive, polysulfide adhesive, silicone adhesive, synthetic rubber adhesive, etc., but since a material with high adhesive strength is preferred, epoxy resin adhesive is preferred.

[0050] The steel plate 30 in the illustrated example is a steel plate with a flat wide surface, but protrusions or recesses (not shown) may be provided on the side surface of the steel plate 30 facing the gap S. For example, protrusions or recesses can be provided on the steel plate 30 by punching (or doweling) the steel plate.

[0051] By providing protrusions and recesses on the side surface of the steel plate 30 facing the adhesive 60, the bonding area between the steel plate 30 and the adhesive 60 can be increased, and the bonding strength between the steel plate 30 and the side surface 12 of the rising portion 11 can be further enhanced.

[0052] Furthermore, by providing recesses on the side surface 12 of the rising portion 11, for example by roughening the surface, the bonding area between the side surface 12 and the adhesive 60 can be increased, thereby further enhancing the bonding strength between the steel plate 30 and the side surface 12 of the rising portion 11 (the above describes the bonding process).

[0053] According to the illustrated example of the joining method, when installing a new column 20 to an existing foundation 10, it is possible to construct a joining structure 100 with high joining strength while eliminating the need for chipping work on the rising section, which is a source of noise, and the installation of anchor bolts.

[0054] More specifically, during an earthquake, the horizontal force acting on the building frame can deform the frame, potentially causing a tensile force N to act on the newly installed column 20. However, the tensile force N can be effectively transmitted to the rising portion 11 of the existing reinforced concrete foundation 10 via the second fastener 40B, the steel plate 30, and the adhesive 60, allowing the existing foundation 10 to resist the tensile force N.

[0055] Here, the illustrated example shows a configuration in which a pair of side surfaces 12 of the rising section 11 of the existing foundation 10 and the left and right sides of the column base 22 of the new column 20 are joined by a pair of steel plates 30. However, a joining structure in which one side surface 12 of the rising section 11 of the existing foundation 10 and the column base 22 of the new column 20 are joined by a single steel plate 30 is also possible.

[0056] Next, with reference to Figure 5, another example of the joint structure between the existing foundation and the newly installed column according to the embodiment will be described.

[0057] The joint structure 100A shown in Figure 5 differs from the joint structure 100 in that the fastener hole 18A provided in the rising portion 11 is a through hole, and the first fastener 45A penetrates the rising portion 11 laterally to connect the pair of steel plates 30.

[0058] In the illustrated example, the inner diameter of the fastener hole 18A, which is a through hole, and the outer diameter of the first fastener 45A are approximately the same. However, even if, for example, the inner diameter of the fastener hole 18A is made larger than the outer diameter of the first fastener 45A to improve the insertion of the first fastener 45A into the fastener hole 18A, the adhesive 60 is filled inside the fastener hole 18A, so the rising portion 11 and the first fastener 45A are effectively joined via the adhesive 60.

[0059] According to the joint structure 100A, the first fastener 45A penetrates the rising section 11 laterally and connects the pair of steel plates 30. Therefore, when a tensile force N acts on the column base 22 of the newly installed column 20, the tensile resistance force N transmitted through the second fastener 40B, the steel plates 30, and the adhesive 60 is resisted not only by the tensile resistance force of the reinforced concrete rising section 11, but also by the bearing resistance force Q of the first fastener 45A that penetrates the rising section 11, thereby improving the tensile strength.

[0060] Furthermore, other embodiments may be used in which other components are combined with the configurations listed in the above embodiments, and the present invention is not limited in any way to the configurations shown herein. In this regard, modifications can be made without departing from the spirit of the present invention, and can be appropriately determined according to the application form. [Explanation of Symbols]

[0061] 10: Existing foundation (cloth foundation) 11: Standing section 12: Side view 14: Top 15: Footing 18: Fastener holes 20: Newly installed pillars 22: Column base block (column base) 30: Steel plate 32A, 32B, 32C: Filling hole 40A: First fastener 40B: Second fastener 50: Sealant 60: Adhesive 100,100A: Joint structure (connection structure between existing foundation and new column) G: Ground S: Gap N: Pull-out force Q: Bearing pressure resistance

Claims

1. A connection structure between an existing foundation and a new column, in which a new column is joined to an existing reinforced concrete foundation, The base of the new column is placed on the top of the rising section of the existing foundation. A joining structure for an existing foundation and a new column, characterized in that a pair of steel plates are arranged so as to straddle the opposing sides of the rising portion and the column base, the steel plates and the column base are joined together, and adhesive is filled in the gap between the sides of the rising portion and the steel plates.

2. The side surface of the rising portion and the steel plate are joined to each other by a first fastener extending in the lateral direction, in a position that secures the gap. The joining structure for an existing foundation and a new column according to claim 1, characterized in that the new column is a steel column, and the column base and the steel plate are joined to each other by a second fastener extending in the lateral direction.

3. The joining structure for an existing foundation and a new column according to claim 2, characterized in that the first fastener penetrates the rising portion laterally and connects the pair of steel plates.

4. The joining structure for an existing foundation and a new column according to claim 1, characterized in that at least the side surface of the steel plate facing the adhesive is provided with a convex portion and / or a concave portion.

5. The joining structure for an existing foundation and a new column according to claim 1, characterized in that a strip-shaped sealing material is arranged along the outer edge of the steel plate on the side surface of the rising portion, and the adhesive is filled into the gap inside the sealing material.

6. A method for joining an existing reinforced concrete foundation to a new column, A column placement step involves placing the base of the new column on the top of the rising section of the existing foundation, A method for joining an existing foundation to a new column, characterized by comprising a joining step of arranging a pair of steel plates so as to straddle the opposing sides of the rising portion and the column base, joining the steel plates to the column base, and filling the gap between the sides of the rising portion and the steel plates with adhesive to join the steel plates to the rising portion.

7. The steel plate has a plurality of filling holes spaced apart in the vertical direction. The method for joining an existing foundation and a new column according to claim 6, characterized in that, in the joining step, adhesive is filled from the lower filling hole, and after confirming that the adhesive has overflowed from a separate filling hole located above, adhesive is filled from the separate filling hole.

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