Multilayered endurance wall structure

Abstract

To provide a continuous-layer load-bearing wall structure to realize a building in which a planar position of a wood load-bearing walls is different in the upper and lower layers.SOLUTION: In a continuous-layer load-bearing wall structure 10 comprising an upper-layer wood load-bearing wall 12, a lower-layer wood load-bearing wall 14, and a beam-shaped boundary member 16 provided between the bottom edge of the upper-layer wood load-bearing wall 12 and the top edge of the lower-layer wood load-bearing wall 14, the boundary member 16 comprises a concrete 24 with an embedded steel frame member 30, the upper wood load-bearing wall 12 is joined to the steel member 16 and secured to anchor bolts 22 protruding upwardly from the boundary member 16, and the lower wood load-bearing wall 14 is joined to the steel member 30 and secured to anchor bolts protruding downwardly from the boundary member 16.SELECTED DRAWING: Figure 1

Description

[[Technical Field]]

[0001] The present invention relates to a multi-story shear wall structure using wooden shear walls. [[Background Art]]

[0002] Conventionally, a CLT panel construction method is known, which constructs buildings by using CLT (Cross Laminated Timber) as panels for floors, walls, roofs and the like (see, for example, Patent Documents 1, 2 and Non-Patent Document 1). [[Prior Art Documents]] [[Patent Documents]]

[0003] [[Patent Document 1]] Japanese Unexamined Patent Application Publication No. 2020-101052 [[Patent Document 2]] Japanese Unexamined Patent Application Publication No. 2019-167766 [[Non-Patent Documents]]

[0004] [[Non-Patent Document 1]] "Design and Construction Manual for Buildings Using CLT 2021, Expanded Edition on Structures and Materials", Japan Housing and Wood Technology Center (public interest incorporated foundation) [[Summary of the Invention]] [[Problems to be Solved by the Invention]]

[0005] In the CLT panel construction method, basically, in order to smoothly transmit compressive / tensile force generated by overturning of wall panels (wooden shear walls) during an earthquake from the upper story to the lower story, it is necessary to align the planar arrangement of the wall panels of the upper story and the lower story (see Non-Patent Document 1). That is, it is necessary to arrange the wall panels of the upper and lower floors such that both side portions thereof are respectively located on the same vertical line. FIGS. 3(a) and 3(b) show an example in which both side portions of the upper and lower wall panels 1 are respectively located on the same vertical line. FIGS. 3(c) and 3(d) show an example in which both side portions of the upper and lower wall panels 1 are not respectively located on the same vertical line. Reference numeral 2 denotes a floor panel (or a beam member).

[0006] Furthermore, in mid-rise and high-rise buildings, as well as low-rise buildings with high floor heights in the upper levels, the compressive / tensile forces on the wall panels increase, requiring measures to reduce the effect of out-of-plane indentation of floor panels (for example, installing metal fittings to prevent indentation on floor panels, or using steel beams or reinforced concrete members in combination).

[0007] These constraints made it difficult to implement architectural plans that combined relatively large spaces and high ceilings in the upper floors using conventional CLT panel construction methods.

[0008] Furthermore, in conventional CLT panel construction methods, tensioning hardware is installed at the top and bottom of the wall panels. However, when a tensioning bolt type connection structure is adopted for this tensioning hardware, a major construction problem has been how to accurately hold the anchor bolts for the upper wall panels, which protrude significantly upward from the concrete structure, while simultaneously pouring the concrete for the structure.

[0009] To solve the above problems, the inventors of this invention investigated a construction method based on the CLT panel method, which uses floor panels and reinforced concrete (RC) floor slabs in combination. In this method, there was a need for technology to realize buildings with structures in which the planar positions of the wall panels on the upper and lower floors differ due to checkerboard patterns and other design requirements.

[0010] The present invention has been made in view of the above, and aims to provide a multi-story shear wall structure for realizing a building in which the planar positions of the wooden shear walls differ between the upper and lower floors. [Means for solving the problem]

[0011] To solve the above-mentioned problems and achieve the objective, the multi-story shear wall structure according to the present invention is a multi-story shear wall structure comprising an upper wooden shear wall, a lower wooden shear wall, and a beam-shaped boundary member provided between the lower end of the upper wooden shear wall and the upper end of the lower wooden shear wall, wherein the boundary member is made of concrete with a steel frame member embedded within it, the upper wooden shear wall is joined to the steel frame member and fixed to anchor bolts protruding upward from the boundary member, and the lower wooden shear wall is joined to the steel frame member and fixed to anchor bolts protruding downward from the boundary member.

[0012] Furthermore, another multi-story shear wall structure according to the present invention is characterized in that, in the above-described invention, the steel frame member is a shaped steel having a horizontal surface.

[0013] Furthermore, another multi-story shear wall structure according to the present invention is characterized in that, in the above-described invention, the anchor bolts are mechanically joined to the steel frame members. [Effects of the Invention]

[0014] The multi-story shear wall structure according to the present invention comprises an upper wooden shear wall, a lower wooden shear wall, and a beam-shaped boundary member provided between the lower end of the upper wooden shear wall and the upper end of the lower wooden shear wall, wherein the boundary member is made of concrete with a steel frame inside, the upper wooden shear wall is joined to the steel frame and fixed to anchor bolts protruding upward from the boundary member, and the lower wooden shear wall is joined to the steel frame and fixed to anchor bolts protruding downward from the boundary member, thereby achieving the effect of realizing a building in which the planar positions of the wooden shear walls differ between the upper and lower floors.

[0015] Furthermore, according to another multi-story shear wall structure of the present invention, since the steel frame member is a structural steel having a horizontal surface, the horizontal surface portion of the structural steel can be used as a fixing plate for anchor bolts, which has the added benefit.

[0016] Further, according to another multi-story shear wall structure according to the present invention, since the anchor bolt is mechanically joined to the steel frame member, there is an advantageous effect that the steel frame member itself can be used as a fixing plate for the anchor bolt to contribute to stress dispersion. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] [Figure 1] Fig. 1 is a side cross-sectional view showing an embodiment of the multi-story shear wall structure according to the present invention. [Figure 2] Fig. 2 is a schematic perspective view showing an installation state of anchor bolts temporarily fixed to steel frame members. [Figure 3] Fig. 3 is a front cross-sectional view showing an arrangement example of wall panels of an upper layer and a lower layer (Source: Non-Patent Document 1). MODE FOR CARRYING OUT THE INVENTION

[0018] Hereinafter, embodiments of the multi-story shear wall structure according to the present invention will be described in detail based on the drawings. It should be noted that the present invention is not limited by this embodiment.

[0019] As shown in Fig. 1, the multi-story shear wall structure 10 according to the embodiment of the present invention includes a wall panel 12 (wooden shear wall of an upper layer) disposed on an upper layer (second floor) of a multi-story building, a wall panel 14 (wooden shear wall of a lower layer) disposed on a lower layer (first floor), and a boundary member 16 provided at a boundary portion between a lower end of the wall panel 12 and an upper end of the wall panel 14. This multi-story shear wall structure 10 is based on the CLT panel construction method, and is applied in a construction method that uses a floor panel 18 and an RC floor slab 20 thereon together, when the arrangement of the upper and lower wall panels 12 and 14 do not planarly coincide due to checkered or other design requirements. In the present embodiment, both side portions of the wall panel 12 and both side portions of the wall panel 14 are not respectively positioned on the same vertical line.

[0020] The wall panels 12 and 14 are CLT panels. In the present embodiment, a CLT panel with a thickness of approximately 200 mm made of a tree species such as cedar is assumed. The upper wall panel 12 is fixed to a plurality of anchor bolts 22 projecting upward from the boundary member 16. The lower wall panel 14 is fixed to a plurality of unillustrated anchor bolts projecting downward from the boundary member 16.

[0021] The boundary member 16 is a steel-framed reinforced concrete (SRC) girder (beam form), and is provided on the side end sides of the floor panel 18 and the RC floor slab 20. This boundary member incorporates reinforcing bars (main bars 26 and stirrups 28) and a steel frame member 30 inside concrete 24 having a rectangular cross section. In the present embodiment, channel steel 32 is used as the steel frame member 30. The channel steel 32 is provided substantially at the center of the cross section of the boundary member 16 and extends in the beam axial direction (the depth direction in FIG. 1). The upper flange 34 of the channel steel 32 is horizontally arranged on the upper side, and the lower flange 36 is horizontally arranged on the lower side. A vertical plate-shaped rib 40 is welded to the concave portion surrounded by the upper and lower flanges 34, 36 and the web 38. The rib 40 has an overhanging portion 42 that overhangs laterally from the concave portion of the channel steel 32, and the upper surface of a horizontal plate-shaped built-in steel material 44 is welded to the lower edge of the overhanging portion 42.

[0022] FIG. 2 shows a state before placing concrete for the boundary member 16. The built-in steel material 44 and the channel steel 32 are temporarily fixed to an unillustrated concrete formwork. As shown in this figure, a plurality of the built-in steel materials 44 are provided at predetermined intervals in the beam axial direction. The ribs 40 are provided on both end sides of the built-in steel material 44 in the beam axial direction. The built-in steel material 44 is provided with a hole penetrating in the vertical direction, and the lower end side of the anchor bolt 22 for fixing the upper wall panel 12 is passed through this hole. Nuts 46 are screwed onto the lower end side of the anchor bolt 22 vertically with the built-in steel material 44 interposed therebetween. The anchor bolt 22 is fixed to the built-in steel material 44 via the nut 46. It should be noted that, regarding the anchor bolt for fixing the lower wall panel 14, since the structure is obtained by inverting this structure, a detailed description thereof will be omitted.

[0023] To balance the compressive force (bearing reaction) and tensile force (anchor bolt anchoring reaction) from the upper wall panel 12 and lower wall panel 14 caused by the overturning of wall panels during an earthquake, the boundary member 16 needs to have sufficient bending shear strength. If the shear performance of the RC beam is insufficient, the beam depth can be reduced by installing a steel member 30 inside the boundary member 16 to make it a SRC beam. When planning a low-rise building, the beam depth of the boundary member 16 can be about 300 mm in a flat shape, and the required performance can be ensured with a relatively lightweight member such as channel steel for the internal steel member 30. In addition to channel steel 32, the internal steel member 30 can also be a shaped steel (e.g., H-beam) with a horizontal surface to ensure the performance as an anchoring plate described later, and other cross-sections can be used as long as they are narrow enough to ensure concrete filling.

[0024] By mechanically and directly joining the anchor bolts 22 for fixing the upper and lower wall panels 12 and 14 to the boundary member 16 to the internal steel member 44 via nuts 46, etc., the internal steel member 44 itself can be used as the anchoring plate instead of the anchoring plate that is often conventionally used as an anchor bolt set, thereby contributing to stress distribution. This is particularly effective when the beam depth of the boundary member 16 is small and it is not possible to secure sufficient length (anchoring length) for fixing the anchor bolts 22 of the wall panels 12 and 14 to the boundary member 16.

[0025] In the CLT panel construction method, each wall panel requires not only anchors for tension bolt connections but also anchors for shear hardware, resulting in a huge number of anchor bolts. In particular, the anchors for tension bolt connections must be of a certain length to ensure sufficient ductility for the building during an earthquake, thereby guaranteeing the axial deformation of the anchor bolts themselves. Therefore, when the anchoring length is short (the beam depth of the boundary member is small), as shown in Figure 1, vertical holes 48, several millimeters larger than the diameter of the anchor bolt, are drilled in the upper and lower end faces of the wall panels 12 and 14, and the anchor bolts 22 are passed through these holes. Separately from the holes 48 for the anchor bolts 22, holes 50 are provided that penetrate horizontally through the wall panels 12 and 14, and the ends of the anchor bolts 22 are bearing and anchored in these holes 50 via anchoring plates 52. The lower end face of the upper wall panel 12 is placed on the upper end face of the boundary member 16 via non-shrink mortar 54. The upper end face of the lower wall panel 14 is placed on the lower end face of the boundary member 16 via a wooden board material (such as a CLT panel) 18A.

[0026] According to this embodiment, seismic forces can be transmitted from the upper wall panel 12 to the lower wall panel 14 via the boundary member 16. This makes it possible to realize a building in which the planar positions of the wall panels 12 and 14 differ between the upper and lower floors, and allows for a highly flexible arrangement of wall panels according to the usage configuration and exterior design of each floor. Furthermore, by using the internal steel material 44, which is temporarily fixed to the concrete formwork of the boundary member 16, as a guide to fasten the anchor bolts 22 protruding from the boundary member 16, the alignment and level of the anchor bolts 22 can be maintained while pouring concrete for the boundary member 16. However, since the anchor bolts 22 cannot be supported solely by the level of the internal steel material 44, it is desirable to separately support the anchor bolts 22 diagonally from the concrete formwork to prevent them from falling over.

[0027] Furthermore, by combining simple joining methods such as screw fastening and nailing, sufficient out-of-plane rigidity can be expected against loads including negative pressure. Compared to conventional CLT panel construction methods, it is possible to realize building spaces with larger spans. In addition, by incorporating diagonal members etc. within the support walls, it is possible to design for fire-resistant buildings.

[0028] As described above, the multi-story shear wall structure according to the present invention comprises an upper wooden shear wall, a lower wooden shear wall, and a beam-shaped boundary member provided between the lower end of the upper wooden shear wall and the upper end of the lower wooden shear wall, wherein the boundary member is made of concrete with a steel frame inside, the upper wooden shear wall is joined to the steel frame and fixed to anchor bolts protruding upward from the boundary member, and the lower wooden shear wall is joined to the steel frame and fixed to anchor bolts protruding downward from the boundary member, so that a building can be realized in which the planar positions of the wooden shear walls are different in the upper and lower layers.

[0029] Furthermore, according to another multi-story shear wall structure of the present invention, since the steel frame member is a structural steel having a horizontal surface, the horizontal surface portion of the structural steel can be used as a fixing plate for anchor bolts.

[0030] Furthermore, according to another multi-story shear wall structure of the present invention, since the anchor bolts are mechanically joined to the steel frame members, the steel frame members themselves can be used as anchoring plates for the anchor bolts, thereby contributing to stress distribution.

[0031] Furthermore, the Sustainable Development Goals (SDGs) are among the 17 international goals adopted at the UN Summit in September 2015. The multi-story shear wall structure according to this embodiment can contribute to achieving some of the 17 SDGs, such as goal 13, "Take urgent action to combat climate change and its impacts." [Industrial applicability]

[0032] As described above, the multi-story load-bearing wall structure according to the present invention is useful for multi-story buildings using wooden load-bearing walls, and is particularly suitable for realizing buildings in which the planar positions of the wooden load-bearing walls differ between the upper and lower floors. [Explanation of Symbols]

[0033] 10 layered load-bearing wall structure 12 Wall panels (upper layer wooden load-bearing walls) 14. Wall panels (lower layer wooden load-bearing walls) 16 Boundary members 18 floor panels 18A plate material 20 Floor slab 22 Anchor bolts 24 Concrete 26 Main reinforcement 28. Muscles of the waist 30 Steel frame members 32 Channel steel 34 Upper flange 36 Lower flange 38 Web 40 Ribs 42 Overhang 44 Internal steel 46 nuts 48,50 holes 52 Fixing plate 54 Non-shrink mortar

Claims

1. A multi-story load-bearing wall structure comprising an upper wooden load-bearing wall, a lower wooden load-bearing wall, and a beam-shaped boundary member provided between the lower end of the upper wooden load-bearing wall and the upper end of the lower wooden load-bearing wall, The boundary member is made of concrete with a steel frame member inside. The upper wooden load-bearing wall is joined to the steel frame member and fixed to anchor bolts that protrude upward from the boundary member. The aforementioned lower layer wooden load-bearing wall is connected to the steel frame member and fixed to anchor bolts that protrude downward from the boundary member, characterized in that it is a multi-story load-bearing wall structure.

2. The multi-story shear wall structure according to claim 1, characterized in that the steel frame member is a shaped steel having a horizontal surface.

3. The multi-story shear wall structure according to claim 1 or 2, characterized in that the anchor bolts are mechanically joined to the steel frame members.

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