Extension construction method and extension structure

Abstract

To provide an extension method and an extension structure that can realize rigid connection of a newly constructed structural material to an existing structure portion while avoiding a decrease in the strength of the existing structure portion when joining the newly constructed steel structural material to the existing structure portion made of concrete.SOLUTION: A newly constructed widening portion 10 made of concrete is constructed on an outer periphery of an existing structure portion 1, and a plurality of through bolts 25 are provided to pass through the newly constructed widening portion 10 along an extending direction of the through bolt that is perpendicular to an extending direction Y of a newly constructed structural material. A pair of joining plates 20 fixed to the newly constructed structural material 50 while facing each other along an extending direction of the through bolt are arranged so as to sandwich the newly constructed widening portion 10 along the extending direction of the through bolt, and are connected to the newly constructed widening portion 10 with the plurality of through bolts 25.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an extension construction method and an extension structure in which a new structural member is joined to an existing concrete structural member extending along a predetermined extension direction of the existing structural member from the side of the existing structural member along an extension direction of the new structural member that is perpendicular to the extension direction of the existing structural member. [Background technology]

[0002] In the extension construction methods and extension structures described above, the use of post-installed anchors embedded in the existing structural parts to join new structural members such as new steel beams to existing structural parts such as existing concrete columns must be avoided because it will result in a decrease in the strength of the existing structural parts. Therefore, although not related to extensions, a technology has been proposed for joining steel structural members to concrete structural parts without using post-installed anchors (see, for example, Patent Document 1). In the technology described in Patent Document 1 (mainly paragraphs 0035-0038 and Figures 1, 3, and 4), when joining a steel beam (2) extending horizontally as the structural material to a precast column member (3) extending vertically as the structural member, a concrete widening portion (6) is constructed on the outer periphery of the precast column member (3), and a plurality of through bolts (8') are provided that pass through the widening portion (6) horizontally, and a base plate (5) fixed to the end of the steel beam is joined to the widening portion (6) by the plurality of through bolts (8'). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-211450 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, a base plate (5) fixed to the end of a steel beam (2) is placed along the side of the widened portion (6) of a precast column member (3) facing the steel beam (2), and the two are connected with multiple through-bolts (8') extending horizontally. When a bending moment generated in the steel beam (2) is transmitted to the precast column member (3), a relatively large tension is applied to each through-bolt (8'). In particular, because these through-bolts (8') are positioned vertically inward of the upper and lower end faces of the steel beam, the tension applied to the through-bolts (8') is large. This tension easily elongates the through-bolts (8'), which have a relatively small cross-sectional area. This elongation of the through-bolts (8') causes a problem in that the connection between the steel beam (2) and the precast column member (3) is no longer rigid. In view of this situation, the main object of the present invention is to provide an extension construction method and extension structure that can rigidly join new structural materials, such as new steel beams, to existing structural parts, such as existing concrete columns, while avoiding a decrease in the strength of the existing structural parts. [Means for solving the problem]

[0005] The first characteristic configuration of the present invention is an extension construction method in which a new structural member extending along a direction perpendicular to the extension direction of the existing structural member is joined to an existing structural member of concrete construction extending along a predetermined extension direction of the existing structural member from the existing structural member side, A new widening section made of concrete is constructed on the outer periphery of the existing structural section, and a plurality of through bolts are provided to penetrate the new widening section along the extending direction of the through bolts perpendicular to the extending direction of the new structural material; A pair of joining plates are fixed to the newly constructed structural material while being arranged opposite each other along the extension direction of the through bolts, and are arranged in a manner that sandwiches the newly constructed widening portion along the extension direction of the through bolts, and are joined to the newly constructed widening portion by the multiple through bolts.

[0006] According to this configuration, a pair of joining plates fixed to the new structural member while facing each other along the direction in which the through-bolts extend, perpendicular to the direction in which the new structural member extends, are attached to both end faces of the new widening section constructed around the existing structural member along the direction in which the through-bolts extend, sandwiching the new widening section along the direction in which the through-bolts extend, and are joined to the new widening section by the multiple through-bolts that penetrate the new widening section. Therefore, the multiple through-bolts for joining the pair of joining plates to the new widening section can be positioned without interfering with the existing structural member, thereby preventing a decrease in the strength of the existing structural member. Furthermore, when a bending moment generated in the new structural member is transmitted to the existing structural member, the bending moment is resisted by stresses generated in the in-plane direction in each of the pair of joining plates. The stresses generated in each of the pair of joining plates are resisted by both the shear force of the multiple through-bolts extending along the direction in which the through-bolts extend, perpendicular to the direction in which the new structural member extends, and the frictional force between the joining plates and the end faces of the new widening section. Therefore, the extension and displacement of the joining plate due to the bending moment can be effectively suppressed, so that the joining of the new structural member to the existing structural member can be maintained in a rigid state. Therefore, the present invention provides an extension construction method that can achieve rigid connection of new structural materials, such as new steel beams, to existing structural parts, such as existing concrete columns, while avoiding a decrease in the strength of the existing structural parts.

[0007] A second characteristic configuration of the present invention is that the existing structural portion is a structural portion of an existing column of reinforced concrete construction extending in a vertical direction as the extension direction of the existing structural portion, The new structural material is a structural material of a new beam that extends in the horizontal direction, which is the extension direction of the new structural material.

[0008] According to this configuration, when joining the structural material of a new beam to the structural part of an existing concrete column, as described above, it is possible to achieve a rigid connection of the new beam to the existing column while avoiding a decrease in the strength of the existing column.

[0009] A third characteristic feature of the present invention is that the extending direction of the through bolt is a direction along the extending direction of the existing structural portion.

[0010] According to this configuration, the new widening section is constructed in a manner that widens the existing structural section in a direction perpendicular to the extension direction of the existing structural section, and a plurality of through bolts extending along the extension direction of the existing structural section are arranged in the new widening section. Therefore, since it is not necessary to widen the existing structural section in the extension direction of the existing structural section when constructing the new widening section, the width of the new widening section along the extension direction of the existing structural section can be minimized, and can be made the same width as the new structural material, for example.

[0011] The fourth characteristic configuration of the present invention is that each of the pair of joining plates is configured in a bifurcated shape having a newly installed structural material fixing piece portion that is fixed to the newly installed structural material, and a pair of newly installed widening portion joining piece portions that extend from the newly installed structural material fixing piece portion toward the existing structural portion in a bifurcated state and are joined to the newly installed widening portion.

[0012] According to this configuration, when viewed in the extending direction of the new structural material, the existing structural material is positioned between a pair of newly installed widening portion connecting pieces that each of the pair of connecting plates has, and the new structural material to which the newly installed structural material fixing pieces that each of the pair of connecting plates has is fixed can be arranged so as to overlap the existing structural material. In this way, force is transmitted from the new structural material to the existing structural material through the pair of connecting plates and the newly installed widening portions approximately uniformly in the width direction of the existing structural material when viewed in the extending direction of the new structural material (a direction perpendicular to the extending direction of the existing structural material and the extending direction of the new structural material), thereby suppressing the generation of torsional force in the existing structural material.

[0013] A fifth characteristic configuration of the present invention is that the newly constructed structural material is made of H-shaped steel, The point is to join the pair of joining plates to both flanges of the new structural material.

[0014] According to this configuration, the bending moment generated in the new structural member made of H-shaped steel is transmitted from the outermost flanges of the new structural member to the pair of connecting plates directly connected to the flanges, and the stress generated in the in-plane direction of each of the pair of connecting plates can be effectively resisted. Therefore, the stress generated in the connecting plates can be minimized, and the elongation and displacement of the connecting plates can be more effectively suppressed.

[0015] The sixth characteristic configuration of the present invention is that a base plate fixed to the end of the web of the newly installed structural material is joined to the side of the newly installed widening section by a plurality of anchor bolts embedded in the newly installed widening section.

[0016] According to this configuration, the shear force generated in the direction perpendicular to the extension direction of the new structural material can be suitably transmitted from the web of the new structural material to the new widening section and the existing structural part through the base plate joined to the web and the anchor bolts joining it to the new widening section. Furthermore, like the through bolts, the anchor bolts can be embedded in the new widening section without interfering with the existing structural part, so that a decrease in the strength of the existing structural part due to the installation of the anchor bolts can be avoided.

[0017] A seventh characteristic configuration of the present invention is an extension structure formed by joining a new structural member extending from an existing concrete structural member extending along a predetermined extension direction of the existing structural member to the new structural member extending along a direction perpendicular to the extension direction of the existing structural member from the existing structural member side, A newly constructed widened section made of concrete constructed on the outer periphery of the existing structural section; a plurality of through bolts provided in a state of penetrating the newly installed widened portion along a through bolt extending direction perpendicular to the extending direction of the newly installed structural material; a pair of joining plates fixed to the new structural material in a state of being arranged opposite each other along the extending direction of the through bolts; The joining plates are arranged in a manner sandwiching the newly installed widened portion along the extending direction of the through bolts, and are joined to the newly installed widened portion by the plurality of through bolts.

[0018] According to this configuration, a pair of joining plates fixed to the new structural member while facing each other along the direction in which the through-bolts extend, perpendicular to the direction in which the new structural member extends, are attached to both end faces of the new widening section constructed around the existing structural member along the direction in which the through-bolts extend, sandwiching the new widening section along the direction in which the through-bolts extend, and are joined to the new widening section by the multiple through-bolts that penetrate the new widening section. Therefore, the multiple through-bolts for joining the pair of joining plates to the new widening section can be positioned without interfering with the existing structural member, thereby preventing a decrease in the strength of the existing structural member. Furthermore, when a bending moment generated in the new structural member is transmitted to the existing structural member, the bending moment is resisted by stresses generated in the in-plane direction in each of the pair of joining plates. The stresses generated in each of the pair of joining plates are resisted by both the shear force of the multiple through-bolts extending along the direction in which the through-bolts extend, perpendicular to the direction in which the new structural member extends, and the frictional force between the joining plates and the end faces of the new widening section. Therefore, the extension and displacement of the joining plate due to the bending moment can be effectively suppressed, so that the joining of the new structural member to the existing structural member can be maintained in a rigid state. Therefore, the present invention makes it possible to provide an extension structure that can rigidly connect a new structural material, such as a new steel beam, to an existing structural part, such as an existing concrete column, while avoiding a decrease in the strength of the existing structural part. [Brief explanation of the drawings]

[0019] [Figure 1] Front view of the existing structure before extension using the extension method of this embodiment [Figure 2] Plan view of the existing structure before expansion using the expansion method of this embodiment [Figure 3] Front view of the extension structure after extension by the extension construction method of this embodiment [Figure 4] Right side view of the extension structure after extension by the extension construction method of this embodiment [Figure 5] Plan view of the extension structure after extension according to the present embodiment DETAILED DESCRIPTION OF THE INVENTION

[0020] An embodiment of an extension method and an extension structure according to the present invention will be described with reference to the drawings. As shown in Figures 3, 4 and 5, the extension construction method (hereinafter referred to as "this extension construction method") and extension structure (hereinafter referred to as "this extension structure") of this embodiment are configured as a construction method and structure in which a new structural member 50 extending from an existing concrete structural member 1 extending along a predetermined extension direction X of the existing structural member is joined from the existing structural member 1 side along a new structural member extension direction Y perpendicular to the extension direction X of the existing structural member. Furthermore, in this extension method and this extension structure, the existing structural part 1 is a joint part 3 where existing beams 5A, 5B are connected to an existing column 2 made of reinforced concrete and extending vertically in the extension direction X of the existing structural part, and the new structural material 50 is a new steel-framed beam 51 made of H-shaped steel and extending horizontally in the extension direction Y of the new structural material.

[0021] The structure of the existing building before this extension method was implemented will be explained based on Figures 1 and 2. In this existing building, existing beams 5A and 5B, also made of reinforced concrete, are connected to a joint 3 of an existing column 2, also made of reinforced concrete. Specifically, the existing beams 5A and 5B are connected to two adjacent sides 3a and 3b of the four sides 3a, 3b, 3c, and 3d around the joint 3. In this extension method and structure, a new beam 51 (see Figures 3, 4, and 5), which will be described later, is connected to side 3c, of the four sides 3a, 3b, 3c, and 3d around the joint 3, to which the existing beams 5A and 5B are not connected.

[0022] Next, the details of this extension construction method and this extension structure will be explained with reference to FIGS. 3, 4 and 5. First, prior to connecting the new beam 51, a new widening section 10 made of concrete is constructed around the outer periphery of the joint 3 of the existing column 2. The new widening section 10 may be made of concrete, but may also be made of reinforced concrete with buried reinforcing bars.

[0023] 3 and 4, the new widening section 10 is constructed in a form that widens the existing column 2 in a horizontal direction perpendicular to the extension direction X (vertical direction) of the existing structural portion. The width (height) of the new widening section 10 along the extension direction X (vertical direction) of the existing structural portion is approximately the same as the width (height) of the new beam 51, and its range includes at least the entire width (height) of the existing beams 5A, 5B. In this embodiment, the upper surface of the new widening section 10 is flush with the upper surfaces of the existing beams 5A, 5B, and the lower surface of the new widening section 10 is located slightly lower than the lower surfaces of the existing beams 5A, 5B.

[0024] As shown in Fig. 5, the new widening portion 10 is formed in a rectangular shape in plan view, with the existing column 2 expanded by approximately the same width around the periphery. Therefore, on the side surface 10a of the new widening portion 10 located outward from the side surface 3a of the existing column 2, the existing beam 5A penetrates the new widening portion 10 and protrudes outward. On the other hand, on the side surface 10b of the new widening portion 10 located outward from the side surface 3b of the existing column 2, the existing beam 5B penetrates the new widening portion 10 and protrudes outward. Then, a new beam 51 (see FIGS. 3, 4 and 5) described later is connected to the side surface 10c of the new widening portion 10 located outside the side surface 3c of the existing column 2.

[0025] 3, 4, and 5, the newly constructed widening section 10 is provided with a plurality of through bolts 25 that penetrate the newly constructed widening section 10 along a through-bolt extending direction Z that is perpendicular to the extending direction Y of the newly constructed structural material. Furthermore, the through-bolt extending direction Z is set to a vertical direction along the extending direction X of the existing structural section. Therefore, in the newly constructed widening section 10 constructed in a form that widens the existing column 2 in a horizontal direction perpendicular to the extending direction X of the existing structural section, the plurality of through bolts 25 that penetrate along the through-bolt extending direction Z that is parallel to the extending direction X of the existing structural section are arranged around the existing column 2 without interfering with the existing column 2. In the new widening portion 10, the through bolts 25 are arranged at locations that avoid interference with the existing beams 5A, 5B in order to avoid a decrease in the strength of the existing beams 5A, 5B. In the newly constructed widened section 10, the through bolts 25 can be provided in a form in which they are directly embedded in concrete, or in a form in which they are inserted into sheath pipes embedded in concrete.

[0026] A pair of joining plates 20 are fixed to the new beam 51 while being arranged opposite each other along the through-bolt extension direction Z (vertical direction) described above. This pair of joining plates 20 is joined to each of the upper and lower flanges 52 of the H-shaped steel constituting the new beam 51 by a plurality of high-strength bolts 26. The pair of joining plates 20 fixed to the new beam 51 are attached to both end faces in the through-bolt extension direction Z (vertical direction) of the new widening portion 10 constructed around the joint portion 3 of the existing column 2, and are arranged in a form that sandwiches the new widening portion 10 along the through-bolt extension direction Z (vertical direction), and are joined to the new widening portion 10 by the plurality of through-bolts 25 described above.

[0027] With the above-described configuration, the plurality of through-bolts 25 for joining the pair of joining plates 20 to the new widening section 10 are positioned so as not to interfere with the joint 3 of the existing column 2, thereby preventing a decrease in the strength of the joint 3 of the existing column 2, which is the existing structural part 1. Furthermore, when a bending moment generated in the new beam 51 is transmitted to the joint 3 of the existing column 2, the bending moment is resisted by in-plane stresses generated in each of the pair of joining plates 20. The stress generated in each of the pair of joining plates 20 is resisted by both the shear force of the plurality of through-bolts 25 in the through-bolt extension direction Z (vertical direction), which is perpendicular to the extension direction Y (horizontal direction) of the new structural member, and the frictional force between the joining plate 20 and the end face of the new widening section 10. Therefore, elongation and displacement of the joining plate 20 due to the bending moment are suitably suppressed, and the connection of the new beam 51 to the joint 3 of the existing column 2 is maintained in a rigid state. Furthermore, the bending moment generated in the new beam 51 is transmitted directly from both flanges 52 arranged on the outermost sides of the new beam 51 to the pair of joining plates 20, and is suitably resisted by the stress along the in-plane direction generated in each of the pair of joining plates 20. Therefore, the stress generated in the joining plates 20 is minimized, and the elongation and displacement of the joining plates 20 are further suitably suppressed.

[0028] 5, each of the pair of joining plates 20 is configured in a bifurcated shape having a new structural material fixing piece 21 fixed to the new beam 51 and a pair of new widening section joint pieces 22A, 22B that extend in a bifurcated state from the new structural material fixing piece 21 toward the joint section 3 of the existing column 2 and are joined to the new widening section 10. The new structural material fixing piece 21 is attached to the end face of the part of the new widening section 10 that is along the side surface 3c of the existing column 2 on the side to which the new beam 51 is connected, while each of the pair of new widening section joint pieces 22A, 22B is attached to the end face of the part of the new widening section 10 that is along the pair of side surfaces 3b, 3d that are adjacent to the side surface 3c of the existing column 2. The newly constructed structural material fixing piece portion 21 and the pair of newly constructed widened portion joining pieces 22A, 22B are joined to the newly constructed widened portion 10 by a plurality of through bolts 25, respectively.

[0029] With this configuration, in the plan view shown in Fig. 5, the joint portion 3 of the existing column 2 is positioned between the pair of newly installed widened portion joint pieces 22A, 22B of each of the pair of joint plates 20, and the new beam 51 to which the newly installed structural material fixing piece 21 of each of the pair of joint plates 20 is fixed can be placed overlapping the joint portion 3 of the existing column 2. Then, the force is transmitted from the new beam 51 to the joint portion 3 of the existing column 2 through the pair of joint plates 20 and the new installed widened portion 10 approximately uniformly in the width direction of the joint portion 3 of the existing column 2 when viewed in the extending direction Y of the new structural material shown in Fig. 4, thereby suppressing the generation of torsional force in the joint portion 3 of the existing column 2.

[0030] As shown in Fig. 4, of the pair of newly constructed widened portion joint pieces 22A, 22B, the first newly constructed widened portion joint piece 22A on one side extends along the side surface 3d to which the existing beam is not connected at the joint portion 3. The second newly constructed widened portion joint piece 22B on the other side extends along the side surface 3b to which the existing beam 5B is connected at the joint portion 3. Therefore, the plurality of through bolts 25 for joining the first newly installed widening portion joint piece 22A of each of the pair of joining plates 20 to the newly installed widening portion 10 can be arranged closer to the newly installed beam 51 because interference with the existing beam is not a problem, and therefore the extension length of the first newly installed widening portion joint piece 22A is made relatively short. On the other hand, the plurality of through bolts 25 for joining the second newly installed widening portion joint piece 22B of each of the pair of joining plates 20 to the newly installed widening portion 10 must be arranged to avoid interference with the existing beam 5B, and therefore the extension length of the second newly installed widening portion joint piece 22B is made relatively long.

[0031] As shown in FIGS. 3 and 4, the web 53 of the new beam 51 is joined to the side surface 10c of the new widening portion 10 via the joining bracket 30 by the anchor bolt 34. That is, the joining bracket 30 is composed of a base plate 31 attached to the side surface 10c of the newly constructed widening portion 10 with grout 36 interposed therebetween, and a gusset plate 32 welded perpendicular to the base plate 31 and attached to the web 53 of the new beam 51. The gusset plate 32 of the joining bracket 30 is joined to the web 53 of the new beam 51 with high-strength bolts 33, thereby fixing the base plate 31 to the end of the web 53. The base plate 31 fixed to the end of the web 53 of the new beam 51 is then fixed to the side surface 10c of the new widening portion 10 with a plurality of anchor bolts 34 embedded in the new widening portion 10. With this configuration, the shear force generated in the new beam 51 in a direction perpendicular to the extending direction Y (vertical direction) of the new structural material is suitably transmitted from the web 53 of the new beam 51 through the connecting bracket 30 and the anchor bolt 34 that connects it to the new widening section 10 to the joint section 3 of the existing column 2. Furthermore, like the through bolt 25 described above, the anchor bolt 34 is embedded in the new widening section 10 without interfering with the joint section 3 of the existing column 2, so that a reduction in the strength of the joint section 3 of the existing column 2 due to the installation of the anchor bolt 34 is avoided.

[0032] [Another embodiment] Other embodiments of the present invention will be described below. Note that the configurations of the embodiments described below are not limited to being applied independently, but can also be applied in combination with the configurations of other embodiments.

[0033] (1) In the above embodiment, the new structural member 50 is a new beam 51 made of H-shaped steel, but the new structural member 50 may be made of a different steel material or material. Also, the new structural member may be a new column connected to the joint at the upper end of an existing column.

[0034] (2) In the above embodiment, the existing structural part 1 is the existing pillar 2 (joint part 3), but the existing structural part may be an existing beam.

[0035] (3) In the above embodiment, the through bolt extension direction Z, which is the extension direction of the multiple through bolts 25 in the newly constructed widening section 10, is set to a direction along the existing structural section extension direction X, which is the extension direction of the existing structural section 1 (existing column 2). However, the through bolt extension direction may be any direction perpendicular to the newly constructed structural material extension direction, which is the extension direction of the newly constructed structural material (e.g., newly constructed beam), and for example, the through bolt extension direction may be set to a direction perpendicular to the existing structural section extension direction.

[0036] (4) In the above embodiment, the joining method of the joining plate 20 to the flange 52 of the newly constructed beam 51 and the joining method of the gusset plate 32 to the web 53 of the newly constructed beam 51 were bolted using high-strength bolts 26, 33, but other joining methods such as welding may also be used.

[0037] (5) Each of the pair of joining plates 20 is configured in a bifurcated branch shape that branches from the newly installed structural material fixing piece portion 21 to a pair of newly installed widening portion joining pieces 22A, 22B, but if there is no problem with strength, the structure of the joining plate 20 may be appropriately modified, for example, by omitting one of the pair of newly installed widening portion joining pieces 22A, 22B. [Explanation of symbols]

[0038] 1 Existing structural section 2 Existing pillar (existing structural part) 3 Connections (existing structural parts) 10 Newly constructed widened section 10c side 20 Joint Plate 21 New structural material fixing piece 22A 1st Newly Installed Widening Section Joint Piece (Newly Installed Widening Section Joint Piece) 22B Second new widening section joint piece (new widening section joint piece) 25 through bolt 31 Base Plate 34 Anchor bolt 50 New structural materials 51 Newly installed beam (newly installed structural material) 52 flange 53 Web X is a pre-existing structural component extending in the direction Y Newly constructed structural material extends in the direction Z through the ball extends in the direction

Claims

1. An extension construction method in which a new structural member is joined to an existing concrete structural member extending along a predetermined extension direction of the existing structural member from the existing structural member side along a new structural member extension direction perpendicular to the extension direction of the existing structural member, A new widening section made of concrete is constructed on the outer periphery of the existing structural section, and a plurality of through bolts are provided to penetrate the new widening section along the extending direction of the through bolts perpendicular to the extending direction of the new structural material; An extension construction method in which a pair of joining plates fixed to the newly constructed structural material while being arranged opposite each other along the extension direction of the through bolts are arranged in a form that sandwiches the newly constructed widening portion along the extension direction of the through bolts and are joined to the newly constructed widening portion by the multiple through bolts.

2. The existing structural portion is a structural portion of an existing reinforced concrete column extending in a vertical direction as the extension direction of the existing structural portion, 2. The method for extension of a building according to claim 1, wherein the newly constructed structural material is a structural material for a newly constructed beam extending in a horizontal direction, which is the extending direction of the newly constructed structural material.

3. The extension method according to claim 1 or 2, wherein the extending direction of the through bolt is a direction along the extending direction of the existing structural portion.

4. The extension construction method described in claim 3, wherein each of the pair of joining plates is configured in a bifurcated branch shape having a newly installed structural material fixing piece portion that is fixed to the newly installed structural material, and a pair of newly installed widening section joining piece portions that extend from the newly installed structural material fixing piece portion toward the existing structural section in a bifurcated state and are joined to the newly installed widening section.

5. The new structural material is made of H-shaped steel, 3. The method for extension according to claim 1, wherein the pair of joining plates are joined to both flanges of the new structural member.

6. An extension construction method as described in claim 5, in which a base plate fixed to the end of the web of the newly constructed structural material is joined to the side of the newly constructed widening section by a plurality of anchor bolts embedded in the newly constructed widening section.

7. An extension structure in which a new structural member is joined to an existing concrete structural member extending along a predetermined extension direction of the existing structural member from the existing structural member side along the extension direction of the new structural member perpendicular to the extension direction of the existing structural member, A newly constructed widened section made of concrete constructed on the outer periphery of the existing structural section; a plurality of through bolts provided in a state of penetrating the newly installed widened portion along a through bolt extending direction perpendicular to the extending direction of the newly installed structural material; a pair of joining plates fixed to the new structural material in a state of being arranged opposite each other along the extending direction of the through bolts; An extension structure in which the joining plate is arranged in a manner that sandwiches the newly constructed widening portion along the extension direction of the through bolts and is joined to the newly constructed widening portion by the multiple through bolts.

Images