JP2016000942A - Joining structure and joining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joining structure and a joining method that facilitate fitting of an anchor plate on an existing reinforcing bar of an existing building.SOLUTION: A joining structure 1 of the present invention is for joining a girder 2 that constitutes an existing building S1 with a girder 3 located below the girder 2. A space K1 is formed between the girder 2 and the girder 3. The joining structure 1 includes a reinforcing bar 4A previously embedded in the existing building S1 and extending into the space K1 from the girder 2, a reinforcing bar 4C previously embedded in the existing building S1 and extending into the space K1 from the girder 3, an anchor plate 21 having an insertion hole for inserting the reinforcing bar 4A, an anchor plate 22 having an insertion hole for inserting the reinforcing bar 4C, a foundation part 5 into which the reinforcing bar 4A and the anchor plate 21 fixed on the reinforcing bar 4A are embedded, and a foundation part 6 into which the reinforcing bar 4C and the anchor plate 22 fixed on the reinforcing bar 4C are embedded.

Description

  The present invention relates to a joining structure and a joining method constructed when an existing building is improved.

  Various techniques for improving existing buildings, such as seismic isolation of existing buildings called seismic isolation retrofit, are known. Japanese Unexamined Patent Application Publication No. 2009-144494 describes a seismic isolation method for an existing building in which the upper part of the first floor of the existing building is a seismic isolation building. In this gazette, new piles are placed at four locations on the outside and below the existing pillars of the existing building and slightly away from the existing building, and new foundation footings are provided on the new piles. A seismic isolation method is described, in which a seismic isolation device outside the building, which is a laminated rubber, is placed on top. The new foundation footing is reinforced by a new foundation frame located in the lower part thereof, and the new foundation frame is connected to the foundation frame of the existing building. Further, on the seismic isolation device outside the building, a new outer peripheral frame composed of an upper footing and a first floor beam is provided, and this new outer peripheral frame is integrated with an existing pillar of an existing building.

  Further, in the above publication, a main reinforcement for reinforcing a large beam is inserted into a through-hole formed in an existing pillar, and a grout material is filled in a gap between the main reinforcement and the through-hole, and an end of the through-hole of the existing pillar is provided. A technique is described in which a fixing plate of the main reinforcing bar is attached to the outer side of the fixing bar and the fixing plate is fixed by a reinforcing bar nut. In this way, a joint structure in which the main bars are fixed is constructed by placing the concrete after filling the grout material and attaching the fixing plate.

  Japanese Patent Application Laid-Open No. 6-57952 describes a fixing structure for main bars using a fixing plate. This publication describes a main bar intermediate fixing screw fixing plate integrally including a disk-shaped fixing plate portion and a hexagonal columnar screw portion, and the fixing plate portion and the screw portion are arranged in the axial direction. A threaded hole for attaching a main bar penetrating therethrough is formed. Moreover, in this gazette, a screw reinforcement is used as a main reinforcement. The screw rebar is inserted into the screw hole, and a high-strength non-shrink mortar is injected between the screw rebar and the screw hole, thereby fixing the screw rebar.

  Furthermore, as a method of attaching the fixing plate to the reinforcing bar, a method of forming a hump by attaching a cast iron ring to the tip of the reinforcing bar and heating and pressurizing the reinforcing bar, and a fixing plate at the end of the deformed reinforcing bar There is also known a method of directly joining by the above.

JP 2009-144494 A JP-A-6-57952

  By the way, the screw fixing plate for fixing the intermediate reinforcing bar can use only a screw reinforcing bar as a reinforcing bar. Therefore, in the improvement of the existing building as described above, it is difficult to attach the main bar intermediate fixing screw fixing plate to the existing reinforcing bar of the existing building. In addition, a method of attaching a cast iron ring to the tip of a reinforcing bar and a method of joining a fixing plate to the end of a deformed reinforcing bar with a friction welding machine must be performed in advance at a factory or the like. Therefore, it is difficult to apply these methods to the improvement of existing buildings.

  An object of this invention is to provide the joining structure and joining method which make it possible to attach a fixing board to the existing reinforcement of the existing building easily.

  The joint structure of the present invention is a joint structure that joins an upper structure constituting an existing building and a lower structure located below the upper structure, and between the upper structure and the lower structure. A space is formed and is embedded in an existing building in advance and extends from at least one of the upper structure and the lower structure to the space, a fixing plate having an insertion hole into which the existing rebar is inserted, and an existing rebar And a base portion for embedding a fixing plate fixed to an existing reinforcing bar.

  In the joining structure of the present invention, an existing reinforcing bar extending from at least one of the upper structure and the lower structure into the space and a fixing plate having an insertion hole into which the existing reinforcing bar is inserted are provided. Therefore, it is possible to fix the fixing plate to the existing reinforcing bar by welding or the like with the existing reinforcing bar inserted into the insertion hole of the fixing plate. Therefore, the fixing plate can be easily attached to the existing rebar. In addition, fixing of the fixing plate to such existing reinforcing bars does not need to be performed in advance in a factory or the like, and can be easily performed on site. Therefore, the fixing plate can be easily attached to the existing reinforcing bar of the existing building.

  Further, the insertion hole penetrates in the thickness direction of the fixing plate, and the section of the insertion hole when the fixing plate is cut along a plane parallel to the thickness direction is directed from one side to the other side in the thickness direction. It may be a shape that spreads according to. In this case, by inserting the existing reinforcing bar into the insertion hole in a state where the fixing plate is oriented so that the other side in the thickness direction of the insertion hole faces upward, an insertion region of the welding rod extending upward is formed. Can do. Thus, by forming the insertion region of the welding rod extending upward, the welding rod can be easily inserted into the insertion region from above. Therefore, it is possible to easily and more reliably fix the fixing plate to the existing reinforcing bars.

  Further, the insertion hole penetrates in the thickness direction of the fixing plate, and the section of the insertion hole when the fixing plate is cut along a plane parallel to the thickness direction may have a trapezoidal shape. In this case, in the cross section of the insertion hole having a trapezoidal shape, the insertion hole is inserted by inserting the existing reinforcing bar into the insertion hole in a state in which the fixing plate is oriented so that the longer base of the insertion hole faces upward. It is possible to form an insertion region of a welding rod that spreads upward. Therefore, since the welding rod can be easily inserted, the fixing plate can be easily and surely fixed to the existing reinforcing bars.

  Moreover, you may provide the seismic isolation apparatus fixed to a base part. In this case, since the seismic isolation device using the existing reinforcing bars of the existing building can be installed, the existing reinforcing bars can be effectively used for the seismic isolation of the existing building.

  Moreover, the anchor which fixes a seismic isolation apparatus to a base part is provided, and an anchor may be provided in the position where the cone fracture surface of the anchor in a foundation part cross | intersects the cone fracture surface of the fixing plate fixed to the existing reinforcing bar. Thus, when the cone fracture surface of the anchor intersects the cone fracture surface of the fixing plate, a resistance force against the tensile force of the anchor can be generated in the fixing plate. Therefore, it is possible to more reliably avoid a situation where the anchor is detached from the foundation due to an earthquake or the like, and a stronger seismic isolation structure can be constructed.

  The joining method of the present invention is a joining method in which an upper structure constituting an existing building and a lower structure positioned below the upper structure are joined, and a space is provided between the upper structure and the lower structure. In a state in which the existing reinforcing bar embedded in the existing building in advance is exposed to the space from at least one of the upper structure and the lower structure, and the existing reinforcing bar is inserted into the insertion hole of the fixing plate. The method includes a step of fixing the fixing plate to the existing reinforcing bar, and a step of forming a base portion for burying the existing reinforcing bar and the fixing plate fixed to the existing reinforcing bar.

  In the joining method of the present invention, the fixing plate has an insertion hole for inserting an existing reinforcing bar. Therefore, it is possible to fix the fixing plate to the existing reinforcing bar by welding or the like with the existing reinforcing bar inserted into the insertion hole of the fixing plate. Therefore, the fixing plate can be easily attached to the existing reinforcing bar regardless of the type of the existing reinforcing bar. Further, in the joining method of the present invention, it is not necessary to fix the fixing plate at a factory or the like in advance, and the fixing plate can be easily fixed to the existing reinforcing bar at the site. Therefore, the fixing plate can be easily attached to the existing reinforcing bar of the existing building.

  ADVANTAGE OF THE INVENTION According to this invention, the joining structure and joining method which make it possible to attach a fixing board to the main reinforcement of the existing building easily can be provided.

It is sectional drawing which shows one Embodiment of the junction structure which concerns on this invention. (A) is sectional drawing which shows an upper reinforcing bar and an upper fixing board. (B) is a top view which shows a lower reinforcing bar and a lower fixing plate. (C) is sectional drawing which shows a lower rebar and a lower fixing plate. (A) is a side view explaining the positional relationship between a reinforcing bar and an anchor. (B) is a top view explaining the positional relationship between a reinforcing bar and an anchor. It is process drawing which shows one Embodiment of the joining method which concerns on this invention. It is a figure which shows the junction structure which concerns on a modification. (A) And (b) is sectional drawing which shows the fixing board and reinforcing bar which concern on a modification.

  Hereinafter, embodiments of a bonding structure and a bonding method according to the present invention will be described in detail with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference numerals, and redundant description is omitted.

  As FIG. 1 shows, the junction structure 1 which concerns on this embodiment divided | segmented the pillar 4 of the existing building S1, and the middle floor seismic isolation was performed by installing the seismic isolation apparatus 10 in this parted part. Structure. By installing the seismic isolation device 10 in this way, collapse of the existing building S1 due to an earthquake is prevented. The joint structure 1 has a structure in which a large beam (upper structure) 2 and a large beam (lower structure) 3 are joined by a seismic isolation device 10. The large beam 2 and the large beam 3 constitute an existing building S1. The large beam 2 is connected to the divided upper column 4, and the large beam 3 is connected to the divided lower column 4.

  The column 4 is located above the seismic isolation device 10 and extends vertically, and is positioned below the seismic isolation device 10. The reinforcing bars 4 </ b> B connect the reinforcing bars 4 </ b> A in the horizontal direction. A plurality of reinforcing bars 4C extending in the vertical direction and reinforcing bars 4D connecting the reinforcing bars 4C in the horizontal direction are embedded. Of these reinforcing bars 4A, 4B, 4C, 4D, the reinforcing bars 4A, 4C are the main bars of the column 4, and the reinforcing bars 4B, 4D are the bars of the column 4. The reinforcing bars 4A, 4B, 4C, and 4D are existing reinforcing bars that have already been buried in the existing building S1 before the seismic isolation device 10 is installed. The reinforcing bar 4B and the reinforcing bar 4D are arranged so as to restrain the reinforcing bar 4A and the reinforcing bar 4C, respectively. The reinforcing bar 4A located above the seismic isolation device 10 and the reinforcing bar 4C located below the seismic isolation device 10 were integrated before the column 4 was divided. It is a separate body.

  A concrete foundation 5 is provided between the upper beam 2 and the seismic isolation device 10, and a concrete foundation 6 is provided between the lower beam 3 and the seismic isolation device 10. . The upper base portion 5 protrudes downward from the lower surface of the large beam 2, and the lower base portion 6 protrudes upward from the upper surface of the large beam 3. Embedded in the upper base portion 5 are a plurality of reinforcing bars 5A that extend in the vertical direction and are inserted into the girder 2 from the lower side, and reinforcing bars 5B that connect the reinforcing bars 5A in the horizontal direction. A plurality of reinforcing bars 6A that extend in the vertical direction and are inserted into the girder 3 from the upper side, and reinforcing bars 6B that connect the reinforcing bars 6A in the horizontal direction are embedded in the lower base portion 6. The reinforcing bar 5B and the reinforcing bar 6B are arranged so as to restrain the reinforcing bar 5A and the reinforcing bar 6A, respectively.

  The seismic isolation device 10 includes a cylindrical laminated rubber 11 and a mounting plate 12 provided so as to sandwich the laminated rubber 11 from above and below the laminated rubber 11. The laminated rubber 11 has a structure in which rubber and steel plates are alternately laminated by, for example, vulcanization adhesion. For example, the laminated rubber 11 and the mounting plate 12 are circular in a plan view, are provided concentrically with each other, and the diameter of the mounting plate 12 is larger than the diameter of the laminated rubber 11. The mounting plate 12 is provided with through holes 12 </ b> A for inserting anchor bolts that penetrate vertically, and a plurality of through holes 12 </ b> A are arranged along the circumferential direction of the mounting plate 12.

  The seismic isolation device 10 is installed between the upper base portion 5 and the lower base portion 6, and the mounting plates 12 positioned above and below the base isolation device 10 are respectively fixed to the base portions 5 and 6 by anchors 15. It is fixed to. The anchor 15 is inserted from the through hole 12A of the mounting plate 12 to the inside of the base portions 5 and 6, and the anchor bolt 16 is embedded in the base portions 5 and 6, and is anchored in the base portions 5 and 6. A high nut 17 to which 16 is screwed and a fixing plate 18 attached to the tip of the high nut 17 are provided. In the anchor 15, the high nut 17 and the fixing plate 18 are embedded in the base portions 5 and 6 in advance, and the anchor bolt 16 is inserted (screwed) and fixed after the laminated rubber 11 is installed.

  A reinforcing bar 4 </ b> A of the pillar 4 is embedded in the upper foundation part 5, and a reinforcing bar 4 </ b> C of the pillar 4 is embedded in the lower foundation part 6. Here, the fixing plate 21 is fixed to the lower end portion of the upper reinforcing bar 4A extending in the vertical direction by welding, and the fixing plate 22 is fixed to the upper end portion of the lower reinforcing bar 4C extending in the vertical direction by welding. Has been.

  FIG. 2A is a cross-sectional view of the reinforcing bar 4A and the fixing plate 21 cut along a plane parallel to the thickness direction of the fixing plate 21 (the vertical direction of the paper surface). The fixing plate 21 has a circular plate shape. Since the circular plate-shaped fixing plate 21 has a shape that does not have an apex, it can be easily damaged by the user of the fixing plate 21. In the center of the fixing plate 21, a circular insertion hole 21 </ b> A that penetrates in the thickness direction of the fixing plate 21 in a plan view is formed. The insertion hole 21 </ b> A has a shape that widens from one side to the other side in the thickness direction of the fixing plate 21, and the insertion hole when the fixing plate 21 is cut along a plane parallel to the thickness direction of the fixing plate 21. The cross-sectional shape of 21A is trapezoidal.

  The diameter of the upper bottom portion 21a in the trapezoidal insertion hole 21A is about the same as the diameter of the reinforcing bar 4A inserted into the insertion hole 21A or slightly larger than the diameter of the reinforcing bar 4A. By inserting the reinforcing bar 4A into the insertion hole 21A from above with the orientation of the fixing plate 21 set so that the lower bottom portion 21b of the insertion hole 21A faces upward, the upper side as shown in FIG. An insertion area A1 of the welding rod that extends in the area is formed. With the insertion region A1 formed in this manner, the welding rod is inserted into the insertion region A1 from above, and the filler metal M is injected while gradually moving the welding rod upward from the lower end of the insertion region A1. As a result, the fixing plate 21 is welded to the reinforcing bar 4A.

  As shown in FIGS. 2B and 2C, the fixing plate 22 has a circular plate shape. Like the insertion hole 21A, the fixing hole 22 has an insertion hole 22A having an upper bottom portion 22a and a lower bottom portion 22b. Is formed. By inserting the reinforcing bar 4C into the insertion hole 22A from below with the orientation of the fixing plate 22 set so that the lower bottom portion 22b of the insertion hole 22A faces upward, an insertion area A2 of the welding rod extending upward is formed. The Then, similarly to the fixing plate 21, a welding rod is inserted into the insertion region A2 from above, and the filler metal M is injected while gradually moving the welding rod upward from the lower end of the insertion region A2, thereby reinforcing the reinforcing bar 4C. The fixing plate 22 is welded to.

  Next, the positional relationship between the reinforcing bar 4A and the anchor 15 will be described with reference to FIGS. 3 (a) and 3 (b). FIG. 3A is a side view schematically showing the positional relationship between the reinforcing bar 4A extending downward from the girder 2 and the anchor 15, and FIG. 3B is a schematic diagram showing the positional relationship between the reinforcing bar 4A and the anchor 15. FIG. FIG. First, as shown in the plan view of FIG. 3B, the anchor 15 is located in the vicinity of the reinforcing bar 4 </ b> A located at the four corners of the column 4. Specifically, the anchor 15 is located on or inside the right triangle formed by the reinforcing bars 4A located at the four corners of the column 4 and the two reinforcing bars 4A located adjacent thereto. . 3A, the cone breaking surface C1 of the fixing plate 18 attached to the tip of the high nut 17, that is, the cone breaking surface C1 of the anchor 15 in the base portion 5 is It intersects with the cone breaking surface C2 of the fixing plate 21 fixed to the lower end of the reinforcing bar 4A.

  Here, the cone breaking surface C1 of the anchor 15 has a shape that spreads in a conical shape with the tip of the anchor 15 as a top. The cone breaking surface C2 of the fixing plate 21 has a shape that expands in a conical shape with the fixing plate 21 as a top. Further, the angle of each cone breaking surface C1, C2 with respect to the vertical direction (half apex angle of each cone breaking surface C1, C2) is 45 °, and these cone breaking surfaces C1, C2 are theoretically calculated in advance. It is possible. The positional relationship between the lower fixing plate 22 and the anchor 15 is the same.

  Next, a bonding method for constructing the above-described bonding structure 1 will be described with reference to FIG. In the construction of the joint structure 1, an intermediate floor seismic isolation in which the seismic isolation device 10 is newly installed is performed, and so-called seismic isolation retrofit is performed. First, as shown in FIG. 4 (a), the pillar 4 of the existing building S1 is divided up and down to expose the upper rebar 4A downward from the large beam 2 and the lower rebar 4C upward from the large beam 3. Exposing (exposing the existing reinforcing bars 4A and 4C to the space K1). The pillar 4 is divided by a wire saw or a wall saw. A space K <b> 1 is formed between the large beam 2 and the large beam 3 along with the division of the pillar 4. At this time, two jacks J are arranged on the upper part of the large beam 3 so as to be arranged along the large beam 3, and the large beam 2 is supported above the large beam 3 by these jacks J, thereby forming a space K <b> 1.

  Then, as shown in FIG. 4B, the fixing plate 21 is fixed to the lower end portion of the reinforcing bar 4A extending downward from the large beam 2 by welding, and the fixing plate 22 is fixed to the upper end portion of the reinforcing bar 4C extending upward from the large beam 3. Is fixed by welding (step of fixing the fixing plates 21 and 22 to the existing reinforcing bars 4A and 4C). Specifically, the lower end portion of the reinforcing bar 4A is inserted into the lower bottom portion 21b of the insertion hole 21A of the fixing plate 21 from above, and in this state, the welding rod is inserted into the insertion region A1 and the filler material M is poured into the insertion region A1. As a result, the fixing plate 21 is welded to the reinforcing bar 4A. Then, the upper end portion of the reinforcing bar 4C is inserted into the upper bottom portion 22a of the insertion hole 22A of the fixing plate 22 from below, and in this state, the welding rod is inserted into the insertion region A2 and the melt material M is poured into the insertion region A2. The fixing plate 22 is welded to the reinforcing bar 4C.

  And as shown in FIG.4 (c), concrete is laid and the base part 6 which embedded the reinforcing bar 4C and the fixing board 22, and the reinforcing bars 6A and 6B is formed in the upper part of the large beam 3 (foundation). Part forming step). Thereafter, the anchor bolt 16 is installed and press-fitted, and the seismic isolation device 10 is installed on the upper surface of the base portion 6 by the anchor 15. Then, as shown in FIG. 4 (d), concrete is placed to form the upper base portion 5 in which the reinforcing bars 4 </ b> A and the fixing plate 21 and the reinforcing bars 5 </ b> A and 5 </ b> B are embedded in the lower portion of the large beam 2. Finally, by removing the two jacks J from the space K1, the joining structure 1 including the seismic isolation device 10 is completed.

  As described above, in the joining structure 1 and the joining method according to the present embodiment, the existing reinforcing bar 4A extending from the large beam 2 to the space K1, the existing reinforcing bar 4C extending from the large beam 3 to the space K1, and the insertion hole into which the reinforcing bar 4A is inserted. A fixing plate 21 having 21A and a fixing plate 22 having an insertion hole 22A into which the reinforcing bar 4C is inserted are provided. The fixing plates 21 and 22 can be fixed to the reinforcing bars 4A and 4C by welding or the like with the reinforcing bars 4A and 4C inserted into the insertion holes 21A and 22A of the fixing plates 21 and 22, respectively. It becomes.

  Therefore, the fixing plates 21 and 22 can be fixed to the reinforcing bars 4A and 4C regardless of the types of the existing reinforcing bars 4A and 4C, so that the fixing plates 21 and 22 can be easily attached to the reinforcing bars 4A and 4C. . Further, fixing of the fixing plates 21 and 22 to the reinforcing bars 4A and 4C does not need to be performed in advance in a factory or the like, and can be easily performed on site. Therefore, the fixing plates 21 and 22 can be easily attached to the existing reinforcing bars 4A and 4C in the existing building S1.

  Further, as shown in FIG. 2A, the insertion hole 21A of the fixing plate 21 penetrates in the thickness direction of the fixing plate 21, and the fixing plate 21 is cut along a plane parallel to the thickness direction. The cross section of the insertion hole 21A has a shape that expands from one side to the other side in the thickness direction, that is, a trapezoidal shape. Therefore, the existing rebar 4A is inserted into the insertion hole 21A from above with the fixing plate 21 oriented so that the other side in the thickness direction of the insertion hole 21A (the longer base of the insertion hole 21A) faces upward. By doing so, the insertion area A1 of the welding rod extending upward can be formed. In this way, by forming the welding rod insertion area A1 extending upward, the welding rod can be easily inserted into the insertion area A1 from above. Therefore, the fixing plate 21 can be easily and more reliably fixed to the existing reinforcing bar 4A. The same applies to the existing reinforcing bars 4C and the fixing plate 22.

  Further, as shown in FIG. 1, the existing reinforcing bar 4A and the fixing plate 21 are embedded, and the base part 5 protruding from the large beam 2 to the space K1, and the existing reinforcing bar 4C and the fixing plate 22 are embedded and from the large beam 3. The base part 6 which protrudes in the space K1 and the seismic isolation apparatus 10 fixed to the base parts 5 and 6 are provided. In this way, since the seismic isolation device 10 using the existing reinforcing bars 4A and 4C in the existing building S1 can be installed, the existing reinforcing bars 4A and 4C can be effectively used in the seismic isolation of the existing building S1. .

  Further, as shown in FIGS. 3A and 3B, an anchor 15 for fixing the seismic isolation device 10 to the base portion 5 is provided, and the anchor 15 is a cone fracture surface of the anchor 15 in the base portion 5. C1 is provided at a position that intersects the cone breaking surface C2 of the fixing plate 21 fixed to the existing reinforcing bar 4A. Thus, when the cone breaking surface C1 of the anchor 15 intersects the cone breaking surface C2 of the fixing plate 21, a resistance force against the tensile force of the anchor 15 can be generated in the fixing plate 21. Therefore, it is possible to more reliably avoid the situation where the anchor 15 is detached from the base portion 5 due to an earthquake or the like, and a stronger seismic isolation structure can be constructed. The same applies to the lower fixing plate 22 and the anchor 15.

  Further, as shown in FIG. 1, by fixing the fixing plates 21 and 22 to the reinforcing bars 4A and 4C in the base portions 5 and 6, when the anchor 15 is pulled by an earthquake or the like, the fixing plates 21 and 22 A bearing pressure is generated. Therefore, even if the height of the space K1 or the height of the exposed reinforcing bars 4A, 4C is low, the bases 5, 6 and the reinforcing bars 4A, 4A, 4C can be transmitted.

  Further, the fixing plates 21 and 22 are fixed to the tip portions of the reinforcing bars 4A and 4C, and the cone breaking surfaces of the fixing plates 21 and 22 face each other so as to overlap the cone breaking surface of the fixing plate 18 in the anchor 15. Therefore, the resistance force of the fixing plates 21 and 22 acts conically with respect to the force with which the anchor 15 is pulled. Further, as shown in FIG. 3B, the anchor 15 is on a right triangle formed by the reinforcing bars 4A located at the four corners of the column 4 and the two reinforcing bars 4A located adjacent thereto, or at a right angle thereof. Located inside the triangle. Therefore, a resistance force against the tensile force of the anchor 15 can be generated by the three reinforcing bars 4A.

  The present invention is not limited to the above-described embodiment, and various modifications as described below are possible without departing from the gist of the present invention.

  For example, in the above-described embodiment, the joint structure 1 that is a structure in which the intermediate floor seismic isolation is performed by installing the seismic isolation device 10 has been described. However, as shown in FIG. 5, it may be a joint structure 31 in which the base isolation is performed by installing the base isolation device 10 in the base pit P. As described above, the present invention can be applied not only to the intermediate floor base isolation but also to the base isolation. The joint structure 31 shown in FIG. 5 is the same as the joint structure 1 of the above embodiment except that the seismic isolation device 10 is installed in the foundation pit P of the existing building S2. In this way, the method of performing seismic isolation at the foundation portion of the existing building S2 is referred to as a base pit seismic isolation method. This base pit seismic isolation method is adopted when the height of the space K2 in the base pit P can be secured to some extent.

  In the joint structure 31 in which the seismic isolation device 10 is installed in the foundation pit P of the existing building S2, the construction is performed only below the use space K3 used by the user of the existing building S2. Therefore, it is possible to reduce the construction range, and it is possible to make it difficult to transmit the sound and vibration generated along with the construction to the use space K3. In addition, in the joint structure 31 in which the seismic isolation device 10 is installed in the base pit P of the existing building S2, it is not necessary to move the user of the existing building S2 along with the construction. Construction can be done without hindering. Furthermore, since there is a low possibility that there is a combustible material below the use space K3 of the existing building S2, there is an advantage that the fireproof coating of the joining structure 31 is unnecessary.

  In the above-described embodiment, an example in which the shape of the insertion hole 22A when the fixing plate 22 is cut along a plane parallel to the thickness direction is a trapezoid has been described. However, the shape of the insertion hole can be appropriately changed as long as the existing reinforcing bar can be inserted. For example, as shown in FIG. 6A, instead of the fixing plate 21 or the fixing plate 22, the cross-sectional shape of the insertion hole 42A when cut along a plane parallel to the thickness direction is a parabolic shape. A plate 42 may be used. Further, as shown in FIG. 6B, a fixing plate 52 in which the cross-sectional shape of the insertion hole 52A when cut along a plane parallel to the thickness direction is an arc may be used. However, in the case of the fixing plates 21 and 22 of the above-described embodiment having a trapezoidal cross-sectional shape, there is an advantage that the welding amount can be suppressed as compared with the fixing plates 42 and 52.

  In the above embodiment, the seismic isolation device 10 including the laminated rubber 11 and the mounting plate 12 and the anchor 15 including the anchor bolt 16, the high nut 17, and the fixing plate 18 have been described. The structure can be changed as appropriate. In the above embodiment, the fixing plates 21 and 22 each having a circular plate shape have been described. However, the shape of the fixing plate can be changed as appropriate. For example, instead of the circular plate-shaped fixing plates 21 and 22, a rectangular plate-shaped fixing plate may be used. The rectangular plate-shaped fixing plate can be processed without waste and can be easily manufactured.

  In the above embodiment, the fixing plate 21 and the existing reinforcing bar 4A are embedded in the upper base portion 5, and the fixing plate 22 and the existing reinforcing bar 4C are embedded in the lower base portion 6. An example was described. However, the present invention is not limited to this example, and a fixing plate and an existing reinforcing bar may be embedded in one of the upper base portion 5 and the lower base portion 6.

DESCRIPTION OF SYMBOLS 1,31 ... Joint structure, 2 ... Large beam (upper structure), 3 ... Large beam (lower structure), 4 ... Column, 4A, 4C ... Reinforcement (existing reinforcing bar), 5, 6 ... Base part, 10 ... Seismic isolation Device, 15 ... Anchor, 16 ... Anchor bolt, 17 ... High nut, 18 ... Fixing plate, 21, 22, 42, 52 ... Fixing plate, 21A, 22A, 42A, 52A ... Insertion hole, C1, C2 ... Cone breaking surface , K1, K2 ... space, S1, S2 ... existing buildings.

Claims (6)

In a joining structure that joins an upper structure constituting an existing building and a lower structure positioned below the upper structure,
A space is formed between the upper structure and the lower structure,
Embedded in the existing building in advance, existing reinforcing bars extending into the space from at least one of the upper structure and the lower structure;
A fixing plate having an insertion hole into which the existing reinforcing bar is inserted;
A foundation portion for burying the existing reinforcing bar and the fixing plate fixed to the existing reinforcing bar;
A joining structure characterized by comprising: The insertion hole penetrates in the thickness direction of the fixing plate,
The cross section of the insertion hole when the fixing plate is cut along a plane parallel to the thickness direction has a shape that widens from one side to the other side in the thickness direction. The joining structure according to 1. The insertion hole penetrates in the thickness direction of the fixing plate,
The joint structure according to claim 1, wherein a cross section of the insertion hole when the fixing plate is cut along a plane parallel to the thickness direction is trapezoidal.   The joint structure according to claim 1, further comprising a seismic isolation device fixed to the base portion. An anchor for fixing the seismic isolation device to the foundation,
The anchor is provided at a position where a cone fracture surface of the anchor in the foundation portion intersects with a cone fracture surface of the fixing plate fixed to the existing reinforcing bar.
The joining structure according to claim 4. In the joining method of joining the upper structure constituting the existing building and the lower structure located below the upper structure,
A space is formed between the upper structure and the lower structure, and an existing reinforcing bar previously embedded in the existing building is exposed to the space from at least one of the upper structure and the lower structure. Process,
Fixing the fixing plate to the existing reinforcing bar in a state where the existing reinforcing bar is inserted into the insertion hole of the fixing plate;
Forming the foundation for embedding the existing reinforcing bar and the fixing plate fixed to the existing reinforcing bar;
A joining method characterized by comprising:

Images