Endurance wall structure

Abstract

We provide load-bearing wall structures that combine the necessary strength and aesthetic appeal. [Solution] The load-bearing wall structure (load-bearing wall 100) includes an upper mounting portion 120 for attaching an upper beam 305U, a lower mounting portion 140 for attaching a lower beam 305L, and a perforated wooden load-bearing panel 110 installed between the upper beam and the lower beam, having at least one opening 151, 152 positioned to avoid the upper and lower mounting portions and penetrating in the thickness T direction, an upper joining member (steel plate damper 170, T-shaped steel 190) for joining the upper mounting portion to the upper beam, and a lower joining member (U-shaped steel plate 200, base 210) for joining the lower mounting portion to the lower beam, wherein at least one of the upper joining member and the lower joining member is equipped with a damper that deforms in accordance with the positional displacement when the upper beam and the lower beam are displaced relative to each other in the longitudinal direction of each beam.

Description

Technical Field

[0001] The present invention relates to a shear wall structure.

Background Art

[0002] In some cases, small openings for equipment (e.g., holes for inserting equipment pipes and electrical wiring) are formed through a wooden facing material used in a building. When an opening is provided in the wooden facing material, cross-sectional loss and stress concentration occur, resulting in a decrease in the shear strength of the wooden facing material. Particularly, when the wooden facing material is composed of structural plywood and is used as a shear wall, even if an opening has to be provided in the wooden facing material, it is necessary to limit the size of the opening extremely or reinforce the periphery of the opening to maintain the required shear strength. Also, the number of openings itself is extremely limited.

[0003] Patent Document 1 describes a wooden material reinforcing member for reinforcing an opening formed in a wooden material. The wooden material reinforcing member includes a cylindrical reinforcing piece inserted into the opening, and an annular opening reinforcing piece that is continuous with one end in the axial direction of the reinforcing piece and is attached to the wall surface around the opening. Although the wooden material reinforcing member is said to have little influence on the appearance design of the wooden material, since the reinforcing material itself appears outside the opening, it does not mean that there is no influence on the appearance design.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventional shear walls using wooden facing materials tend to have a closed design because it is difficult to create openings in terms of shear strength. If the openings are reinforced, the design becomes cumbersome, and in either case, the visual lightness is sacrificed. This invention has been made in view of the above circumstances, and aims to provide a load-bearing wall structure that combines the necessary load-bearing capacity with aesthetic appeal. [Means for solving the problem]

[0006] To solve the above problems, the present invention provides a perforated wooden load-bearing panel installed between the upper beam and the lower beam, having an upper mounting portion for attaching an upper beam, a lower mounting portion for attaching a lower beam, and at least one opening that penetrates in the thickness direction and is positioned to avoid the upper mounting portion and the lower mounting portion, an upper joining member for joining the upper mounting portion to the upper beam, and a lower joining member for joining the lower mounting portion to the lower beam, wherein at least one of the upper joining member and the lower joining member is provided with a damper that deforms in accordance with the positional displacement when the upper beam and the lower beam are displaced relative to each other in the longitudinal direction of each beam. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a load-bearing wall structure that combines the necessary load-bearing capacity with aesthetic design. [Brief explanation of the drawing]

[0008] [Figure 1] This is a front view showing the structural plane of a building in which a load-bearing wall relating to one embodiment of the present invention is installed. [Figure 2] (a) is a cross-sectional view of AA in Figure 1, (b) is an enlarged view of the upper part of (a), and (c) is an enlarged view of the lower part of (a). [Figure 3] This diagram shows perforated wood load-bearing panels; (a) is a perspective view, and (b) is a BB cross-section view of (a) (a diagram showing the approximate cross-section). [Figure 4] This is a plan view of a steel plate damper, where (a) shows the state before deformation and (b) shows the state after deformation. [Figure 5] This diagram shows a U-shaped steel plate and base, with (a) being a plan view and (b) being a cross-sectional view. [Figure 6]This diagram shows a flowchart relating to the design method of load-bearing panels. [Figure 7] This is a front view showing the load-bearing sheathing material for a design example, where (a) shows the design before the change and (b) shows the design after the change. [Figure 8] Figures (a) and (b) show the analysis results in the strong axis direction of the load-bearing panels shown in Figures 7(a) and (b), respectively. [Figure 9] Figures (a) and (b) show the analysis results in the weak axis direction of the load-bearing panels shown in Figures 7(a) and (b), respectively. [Figure 10] Figures (a) and (b) show the analysis results related to the shear of the load-bearing panels shown in Figures 7(a) and (b), respectively. [Modes for carrying out the invention]

[0009] The present invention will be described in detail below using embodiments shown in the figures. However, unless otherwise specified, the components, types, combinations, shapes, and relative arrangements described in these embodiments are not intended to limit the scope of the invention to these specific examples, but are merely illustrative examples.

[0010] [First Embodiment] Figure 1 is a front view showing an example of a building frame structure in which a load-bearing wall according to one embodiment of the present invention is installed. Figure 2(a) is a cross-sectional view AA of Figure 1, (b) is an enlarged view of the upper part of (a), and (c) is an enlarged view of the lower part of (a). Figure 3 shows a perforated timber load-bearing panel, (a) is a perspective view, and (b) is a cross-sectional view BB of (a) (a diagram showing the cross-section to be approximated).

[0011] The building 300 comprises a frame 301 which includes a pair of columns 303, 303 and upper and lower beams 305 (upper beam 305U, lower beam 305L) spanning between the columns 303, 303, and a load-bearing wall (load-bearing wall structure) 100 which is arranged within the frame 301.

[0012] The shear wall 100 can be installed in a building 300 with a frame structure. Examples of buildings 300 where the shear wall 100 can be installed include steel frame structures, reinforced concrete structures, wooden structures, etc. Hereinafter, the present invention will be described by an example in which the shear wall 100 is installed in a steel frame structure building 300 where the columns 303, 303 are made of square steel pipes and the beams 305U, 305L are made of H-shaped steel.

[0013] <Shear wall> The shear wall 100 includes a perforated wooden shear panel 110 (hereinafter simply referred to as "shear panel 110") and joining members (steel plate damper 170, T-shaped steel 190, U-shaped steel plate 200, pedestal 210) for joining this to the frame 301. The joining members are provided at the upper and lower parts of the shear wall 100. That is, the shear wall 100 includes upper joining members (steel plate damper 170, T-shaped steel 190) for joining the shear panel 110 to the upper beam 305U at its upper part, and lower joining members (U-shaped steel plate 200, pedestal 210) for joining the shear panel 110 to the lower beam 305L at its lower part.

[0014] In this example, the shear wall 100 includes a steel plate damper 170 as an upper joining member and a U-shaped steel plate 200 as a lower joining member. The shear wall in this embodiment includes a damper for absorbing vibration energy and also has a function as a vibration control wall. At least one of the upper and lower parts of the shear panel is indirectly joined to the beam 305 via the steel plate damper 170. The other of the upper and lower parts of the shear panel 110 may be directly joined to the beam 305. The shear panel 110 may be further joined to the column 303 after being joined to the beam 305.

[0015] <Perforated wooden shear panel> The endurance facing material 110 includes attachment portions (upper attachment portion 120, lower attachment portion 140) for attaching the frame 301, and at least one opening 151…, 152… arranged at a position penetrating in the thickness direction and avoiding the upper attachment portion 120 and the lower attachment portion 140. Note that the attachment portion in this example is a portion indirectly attached to the frame 301 via a joining member, but the attachment portion may also be a portion directly attached to the frame 301.

[0016] The endurance facing material 110 is composed of a wood-based material that can be used as a structural facing material or an endurance wall. Preferably, laminated wood is used as the wood-based material, but the endurance facing material 110 is particularly preferably composed of a cross-laminated timber (CLT material). When the endurance facing material 110 is composed of a cross-laminated timber, the number of layers and plies thereof are selected to satisfy the required design endurance.

[0017] In this example, the endurance facing material 110 is installed such that the vertical direction (height H direction) is the strong axis direction (first direction), and the horizontal direction (width W direction) is the weak axis direction (second direction). Note that the direction orthogonal to both the height direction and the width direction is the thickness T direction of the endurance facing material 110, which is the lamination direction of the laminates in the case of a cross-laminated timber.

[0018] The endurance facing material 110 includes an upper attachment portion 120 for attaching the upper beam 305U via a steel plate damper 170 at the upper end portion, and a lower attachment portion 140 for attaching the lower beam 305L via a U-shaped steel plate 200 at the lower end portion. That is, the endurance facing material 110 includes a first attachment portion (upper attachment portion 120) to which a part of the frame 301 (a proper position of the upper beam 305U) is attached closer to one side in the first direction (vertical direction, strong axis direction), and a second attachment portion (lower attachment portion 140) to which another part of the frame 301 (a proper position of the lower beam 305L) is attached closer to the other side in the first direction.

[0019] <Attachment portion> <<Upper attachment portion>> As shown in Figures 2 and 3, the upper mounting portion 120 includes an upper slit 121 formed downward from the upper end surface 110a of the load-bearing panel 110 to a predetermined thickness and depth, and pin holes 123... and bolt holes 124... that penetrate the formation area of ​​the upper slit 121 in the thickness direction of the load-bearing panel 110 when viewed from the front.

[0020] The upper slit 121 is formed in the middle of the thickness direction of the load-bearing panel 110. The upper slit 121 is a portion of the steel plate damper 170 (Figure 4) that houses the panel joint portion 175 that connects to the load-bearing panel 110 and the damper portion 181 that absorbs vibration energy. The upper slit 121 has a widthwise length that can accommodate the steel plate damper 170 and allows the steel plate damper 170 to deform during its operation. In this example, the upper slit 121 extends over the entire widthwise direction of the load-bearing panel 110, but the upper slit 121 may be provided only in a part of the widthwise direction of the load-bearing panel 110. The widthwise length of the upper slit 121 may be shorter than the widthwise length of the load-bearing panel 110.

[0021] As shown in Figure 2(b), a pair of guide rails 127, 127 are arranged at the upper end of the upper slit 121 so as to sandwich the steel plate damper 170 in the thickness direction. The guide rails 127 are generally L-shaped in side view (cross view) and are made of angle material (angle steel) or the like. The guide rails 127 are attached across the upper end surface 110a of the load-bearing surface material 110 and the inner surface surface 121a of the upper slit 121. The guide rail 127 prevents the steel plate damper 170 from deforming out of plane (in the direction of the thickness T of the load-bearing surface 110) and biting into the load-bearing surface 110. The guide rail 127 restricts the deformation direction of the steel plate damper 170 to within the HW plane.

[0022] The pin holes 123 are round holes into which drift pins DP, which join the load-bearing panel 110 and the steel plate damper 170, are inserted. The pin holes 123 are arranged alternately in a staggered pattern in the height H direction and width W direction within a predetermined range in the middle of the load-bearing panel 110, which is at the far end 121b of the upper slit 121 (the lower end of the upper slit 121 in the figure), and in the width direction of the load-bearing panel 110.

[0023] As shown in Figures 1 and 3, bolt holes 124 are positioned in areas that avoid interference with the steel plate damper 170. The bolt holes 124 are round holes into which the shaft portion of the opening-preventing member 160 (see Figure 2(c)) is inserted. The opening-preventing member 160 is a member that prevents the spacing of the upper slits 121 from expanding in the thickness direction of the load-bearing surface material 110.

[0024] Referring to Figure 2(c), the opening prevention member 160 is composed of a bolt B, a nut N, and large-diameter washers 161, 161 that prevent the head of the bolt B and the nut N from biting into the load-bearing panel 110. Furthermore, recesses 125 of a predetermined depth are formed on both sides of the load-bearing panel 110 around the bolt hole 124 to accommodate the entirety of the large-diameter washers 161, 161. In this example, the recesses 125 are circular in front view. The recesses 125 have a depth (length in the thickness direction T) that prevents the opening prevention member 160 from protruding from the surface of the load-bearing panel 110.

[0025] <<Lower mounting section>> As shown in Figures 2 and 3, the lower mounting portion 140 includes a lower slit 141 formed to a predetermined thickness and depth extending upward from the lower end surface of the load-bearing panel 110, and pin holes 143... and bolt holes 144... that penetrate the area formed by the lower slit 141 in the thickness direction of the load-bearing panel 110 when viewed from the front.

[0026] The lower slit 141 is formed in the middle of the thickness direction of the load-bearing panel 110. The lower slit 141 is U-shaped when viewed from the front. A U-shaped steel plate 200 is inserted into the lower slit 141.

[0027] The pin holes 143 are round holes into which drift pins DP are inserted to join the load-bearing panel 110 and the U-shaped steel plate 200. The pin holes 143 are arranged alternately in a staggered pattern in the height H direction and width W direction at both ends of the lower slit 141 in the width direction and in the middle of the lower slit 141 in the width direction.

[0028] As shown in Figures 1 and 3, bolt holes 144… consisting of round holes into which the shaft portion of the anti-opening member 160 is inserted are arranged near the lower corner of the load-bearing panel 110, and recesses 145 of a predetermined depth are formed on both sides of the load-bearing panel 110 around the bolt holes 144 to accommodate the entirety of the large-diameter washers 161, 161. The structure of the recesses 145 is the same as that of the recesses 125. Furthermore, the structure and effect of the anti-opening member 160 are as described above.

[0029] <Opening> As shown in Figures 1 and 2, the load-bearing panel 110 has openings 151 and 152 in areas that avoid the upper mounting portion 120 and the lower mounting portion 140. In this example, opening 151 is triangular in shape, and opening 152 is circular in shape. Openings 151 and 152 are mainly provided for ventilation, lighting, and to improve aesthetics, but they may also be used as openings for equipment such as pipes and wiring.

[0030] <groove> The load-bearing panel 110 is provided with grooves 153 that do not penetrate in the thickness direction T. These grooves 153 are primarily for aesthetic purposes. The grooves 153 are appropriately distributed throughout the entire surface of the load-bearing panel 110. In this example, the openings 151 and 152 and the groove 153 are arranged to be continuous, or the groove passes through the opening. As a result, there are portions where the thickness around the openings 151 and 152 is smaller than the total thickness t1 of the load-bearing panel 110. In this example, the depth d of the groove 153 is constant throughout the entire surface of the load-bearing panel 110, but the depth d of the groove 153 may be varied depending on the part of the load-bearing panel 110.

[0031] <Upper connecting member ~ steel plate damper> Figure 4 is a plan view of a steel plate damper, where (a) shows the state before deformation and (b) shows the state after deformation. The steel plate damper 170 deforms when the upper beam 305U and the lower beam 305L are displaced relative to each other in the longitudinal direction, preventing a load exceeding the required value from being applied to the load-bearing panel 110.

[0032] The steel plate damper 170 comprises a beam joint portion 171 joined to the upper beam 305U, a panel joint portion 175 attached to the load-bearing panel 110, and a damper portion 181 positioned between the two joint portions 171 and 175 and displaced by shear force. The beam joint 171 has multiple round holes 172 through which the shafts of bolts can be inserted. The panel joint 175 has multiple elongated holes 176 through which drift pins can be inserted and which extend in the height H direction.

[0033] The damper portion 181 comprises a plurality of damper holes 182 that penetrate the plane, and a plurality of column portions 185 formed on both sides of each damper hole 182. The damper hole 182 is an elongated hole extending between the beam joint 171 and the panel joint 175, and the damper hole 182 has a bulging shape in the middle of its longitudinal direction (the direction connecting the beam joint 171 and the panel joint 175). Each damper hole 182 has a semicircular portion 183 at each end in the longitudinal direction, and straight portions 184, 184 that are inclined so that the opening width gradually increases from the semicircular portion 183 to the middle in the longitudinal direction. The column portion 185 is the part that connects the beam joint 171 and the panel joint 175, and its middle in the longitudinal direction is a narrow portion 186.

[0034] As shown in Figure 4(b), when the beam joint 171 and the panel joint 175 are subjected to a load F and are displaced relative to each other in the width W direction, the column 185 deforms due to shear and absorbs energy.

[0035] The elongated holes 176 in the panel joint 175 transmit the load in the width direction W, but not in the height direction H. For example, if the distance between the beam joint 171 and the panel joint 175 is shortened due to deformation of the damper section 181, the position of the drift pin is displaced vertically relative to the elongated holes 176, thereby preventing the load in the height direction H from being transmitted to the load-bearing panel 110 via the drift pin.

[0036] The steel plate damper 170 is joined to the upper beam 305U by an appropriate method. As shown in Figures 1 and 2, in this example, the flange 191 of the T-shaped steel 190 is fastened to the lower flange 306 of the upper beam 305U, which is an H-shaped steel, by bolts B and nuts N, and the web 192 of the T-shaped steel 190 and the beam joint portion 171 of the steel plate damper 170 are fastened to each other using bolts B and nuts N via splice plates 195, 195 attached to both sides. However, the method of joining the steel plate damper 170 to the upper beam 305U is not limited to this.

[0037] <Lower joint ~ U-shaped steel plate> Figure 5 shows a U-shaped steel plate and base, where (a) is a plan view and (b) is a cross-sectional view of the cross section. The U-shaped steel plate 200 is a steel plate with a roughly angular U-shape, in which both ends in the width direction W protrude upward. The U-shaped steel plate 200 comprises an intermediate piece 201 located in the middle of the width direction, and two end protruding pieces 203, 203 located at both ends in the width direction and protruding in the same direction (upward). The U-shaped steel plate 200 is joined to the load-bearing face material 110 to the lower beam 305L in a rigid manner, or is rigidly joined.

[0038] Multiple elongated holes 202 are formed through the plane of the intermediate piece 201, allowing the insertion of a drift pin DP and extending in the height H direction. The elongated holes 202 are arranged alternately in a staggered pattern in the height H direction and the width W direction. The elongated holes 202 transmit the load in the width W direction but not in the height H direction. The elongated holes 202 transmit shear loads.

[0039] Multiple circular holes 204 and 205 are formed through the plane of the end projection 203. The circular holes 204 and 205 are arranged alternately in a staggered pattern in the height H direction and the width W direction. As shown in Figure 2(c), a drift pin DP is inserted through the upper circular hole 204. The circular hole 204 transmits tensile load. The shaft portion of the bolt B that constitutes the opening stopper member 160 is inserted through the lower circular hole 205.

[0040] The U-shaped steel plate 200 is joined to the lower beam 305L by an appropriate method. As shown in Figure 2(c), in this example, the U-shaped steel plate 200 is joined to the lower beam 305L via a base 210. As an example, the base 210 comprises an H-shaped steel beam 211 and a plurality of reinforcing ribs 215 positioned appropriately along the longitudinal direction of the H-shaped steel beam 211. The reinforcing ribs 215 are generally rectangular flat plates, with three ends welded to the lower flange 212, upper flange 213, and web 214 of the H-shaped steel beam 211, respectively. The lower end edge of the U-shaped steel plate 200 is welded to the upper flange 213 of the base 210 and integrated with it.

[0041] The base 210 is placed on the lower beam 305L, and the lower flange 212 of the base 210 is fastened to the upper flange 307 of the lower beam 305L with bolts B and nuts N, thereby joining the U-shaped steel plate 200 to the lower beam 305L via the base 210. However, the method of joining the U-shaped steel plate 200 to the lower beam 305L is not limited to this.

[0042] [Design method] Figure 6 is a flowchart showing the design method for load-bearing panels. The design method for load-bearing panels involves the following steps: preliminary design (S10), estimation (S20), analysis (S30), extraction (S40), and redesign (S50).

[0043] <Preliminary Design Process (S10)> The preliminary design process (S10) is a process for preliminary designing a load-bearing panel having an in-plane opening that penetrates in the thickness direction. In this process, for example, a load-bearing panel 110 with openings 151 and 152 and a groove 153, as shown in Figure 3, is designed. In the preliminary design process, the load-bearing panel is preliminary designed using 3D-CAD software installed on a computer. The 3D-CAD data created in this process is loaded into finite element analysis software in the analysis process (S30).

[0044] <Estimated process (S20)> In the preliminary calculation stage (S20), the provisionally designed load-bearing panels 110 are verified using approximate values. In this stage, the structural performance of the load-bearing panels 110 is estimated, and any load-bearing panels 110 that clearly do not possess the necessary strength are excluded from the finite element method analysis. In addition, approximate indicators are obtained regarding the size and quantity of openings. The estimation process includes a load input section setting process (S21), an estimation target cross section setting process (S22), a bending stress calculation process (S23), a bending stress verification process (S24), a shear stress calculation process (S25), and a shear stress verification process (S26).

[0045] Here, we will explain the concepts related to the preliminary process with reference to Figure 4. The load input section 401 is the part that inputs the design load to the load-bearing surface 110. The approximate section 402 is the section within the load-bearing panel 110 that is subject to approximate calculation, and is a section perpendicular to the height H direction (a section defined by the width W and thickness T). The area 403 subject to estimation is the area where the cross section 402 subject to estimation can be set, and is set within a predetermined range in the height H direction of the load-bearing surface material 110.

[0046] In step S21, a load input section 401 is set for the load-bearing panel 110. To simplify calculations, the design load is set to a single-point concentrated load. In this embodiment, the load input section is set at an appropriate location on the upper mounting section 120. For example, the load input section (load input point) 401 can be set at the center in the width direction of the group of pin holes 123 joined to the steel plate damper 170, at a height corresponding to the lowest pin hole among the pin holes 123. Here, the design load F is set to be equivalent to the deformation initiation load (operation initiation load) at which the steel plate damper 170 begins to deform (operate). Alternatively, the design load may be set to a value slightly larger than the deformation initiation load, taking into account a safety factor.

[0047] In step S22, the approximate section 402 is set. That is, first, the area between the upper mounting part 120 and the lower mounting part 140 is set as the approximate area 403. Next, among the orthogonal sections perpendicular to the height direction, the section with the smallest effective section modulus Z [mm^3] within the approximate area 403 is set as the approximate section 402.

[0048] Here, the area above the pin hole 123 is not fixed to the upper beam 305U and is not subjected to significant stress, so it is excluded from the scope of the estimated area 403. In the area 403 subject to estimation, a section exhibiting a stress distribution (behavior) similar to that of a cantilever beam subjected to bending stress is defined. Therefore, the upper end 403a of the area 403 subject to estimation can be the position of the lowest pin hole among the pin holes 123, and the lower end 403b can be the position of the highest pin hole among the pin holes 143. By setting the target area 403 for estimation in this way, it becomes easier to compare the estimated value with the results of the finite element method analysis.

[0049] Furthermore, it has been empirically observed that stress tends to concentrate at the edges of openings 151 and 152 located within the estimated area 403. Therefore, setting the estimated area 403 based on the positions of pin holes 123 and 143 is meaningful in order to verify the validity of the bending stress in areas prone to stress concentration through simple calculations. The section 402 targeted for estimation is the location where the shear wall material 110 is most severely damaged by openings 151 and 152. By using the section with the greatest damage as the target for estimation, an index can be obtained regarding the amount of damage caused by openings 151 and 152.

[0050] In step S23, the bending stress is calculated for the approximate cross section 402. Specifically, first, the bending moment M = FL [kNm] acting on the orthogonal cross section including the lower mounting section 140 is calculated when the design load F is input to the load input section 401 along the width W direction perpendicular to the height H direction of the load-bearing surface 110. Next, the effective section modulus Z [mm^3] of the approximate cross section 402 is calculated. Finally, the bending stress σ [N / mm^3] when this bending moment M acts on the approximate cross section 402 is calculated using M / Z.

[0051] In this process, the maximum value of the bending moment M acting on the area 403 to be estimated is used to estimate the bending stress σ. That is, the bending moment M acting on the lower end 403b of the area 403 to be estimated is calculated based on the distance L in the height H direction from the load input section 401. In this process, the bending stress is calculated when the maximum bending moment acts on the approximate cross section 402. Therefore, the actual bending stress acting on the approximate cross section 402 will be smaller than the approximate value.

[0052] The effective section modulus Z of the approximate target section 402 is calculated as follows: Specifically, the effective section modulus Z is calculated based on the distance to the neutral axis by subtracting the second moment of area I2 of each opening from the second moment of area I1 [mm^4] of the orthogonal section when the load-bearing panel 110 has no openings.

[0053] When the load-bearing panel 110 has grooves 153, the effective section modulus Z is calculated using the thickness t2 obtained by subtracting the groove depth d from the total thickness t1 of the load-bearing panel 110. In this example, since there are grooves 153 with depth d on both sides of the load-bearing panel 110, "t2 = t1 - 2d". In this process, the grooves 153 are ignored in the calculation, making the calculation easier and resulting in a result that leans towards safety. If the depth d of the grooves 153 changes within the plane of the load-bearing panel 110, t2 is calculated based on the maximum value of the depth d as a safety selection.

[0054] In step S24, a check is performed to determine if the bending stress is within the standard strength of the wood-based material that forms the basis of the load-bearing panel 110. If the check ratio exceeds 1.0 (exceeds the standard strength, NO in step S24), the preliminary design process in step S10 is executed. If the check ratio is 1.0 or less (within the standard strength, YES in step S24), step S25 is executed.

[0055] In step S25, the shear stress is calculated for the approximate section 402. Specifically, first, the cross-sectional area A [mm^2] of the approximate section 402 is calculated. From the cross-sectional area A and the shear force Q [kN], the shear stress τ [N / mm^2] acting on the approximate section 402 is calculated by Q / A.

[0056] In this process, the maximum value of the shear force acting on the area 403 is used to estimate the shear stress τ. That is, the shear stress τ is calculated when the design load F [kN] acts as a shear force Q on the section 402 of the area 402. In this process, the shear stress is calculated when the maximum load is applied to the approximate cross-section 402; therefore, the actual shear stress of the approximate cross-section 402 will be smaller than the approximate value.

[0057] If the load-bearing panel 110 has grooves 153, the cross-sectional area A is calculated using the thickness t2 obtained by subtracting the groove depth d from the total thickness t1 of the load-bearing panel 110. Since the grooves 153 are ignored in the calculation, the calculation becomes easier. The shear stress to be obtained in this process is the average shear stress of the cross-sectional area A.

[0058] In step S26, a check is performed to determine if the shear stress is within the standard strength of the wood-based material that formed the basis of the load-bearing panel 110. If the check ratio exceeds 1.0 (NO in step S26), the preliminary design process in step S10 is executed. If the check ratio is 1.0 or less (YES in step S26), step S30 is executed.

[0059] In the preliminary calculation phase, the bending stress test is performed for the strong axis direction but not for the weak axis direction. This is because, in this case, the calculation of bending stress is simpler for the strong axis direction than for the weak axis direction, and the possibility of failing the test is higher for the strong axis direction than for the weak axis direction.

[0060] <Analysis process (S30)> In the analysis process (S30), the designed load-bearing panels are analyzed using the finite element method. The analysis process includes a division process (S31) and a finite element method analysis process (S32).

[0061] The analysis process utilizes finite element method analysis software installed on a computer. Examples of such software include midas iGen (registered trademark) from MIDAS IT Japan Co., Ltd. In this process, the 3D-CAD data of the provisionally designed load-bearing panels is loaded into the finite element method analysis software for analysis. If the load-bearing panel 110 has grooves 153, the analysis is performed using the thickness t2 obtained by subtracting the groove depth d from the total thickness t1 of the load-bearing panel 110, similar to the preliminary calculation process (S20).

[0062] In step S31, the load-bearing panel is divided into multiple finite elements. Circular and curved sections are approximated as appropriate by combinations of polygons and line segments.

[0063] In step S32, a finite element method analysis is performed. In finite element analysis, the bending stress in the strong axis direction (compression and tension directions), the bending stress in the weak axis direction (compression and tension directions), and the shear stress are calculated for each element. Unlike the preliminary calculation process, this step involves distributing the design load to each pinhole 123 and inputting it.

[0064] <Extraction process (S40)> In the extraction process (S40), the stress of each element calculated in the analysis process is verified based on the standard strength of the wood-based material that formed the basis of the load-bearing panel 110. Elements whose stress exceeds the standard strength, or elements whose stress is close to the standard strength, are extracted as unsuitable elements. In principle, each element can be considered a passing element if its test value is 1.0 or less. However, even if an element has a test value of 1.0 or less, if the test value is relatively high (for example, exceeding 0.8), it may be deemed a failing element as a precaution.

[0065] If unsuitable elements are identified (YES in step S40), the redesign process in step S50 is executed. If no unsuitable elements are identified (NO in step S40), the designed load-bearing panel is used as the target load-bearing panel, and the process is terminated.

[0066] <Provisional redesign process (S50)> In the redesign process (S50), the load-bearing panels are redesigned by rearranging the openings on the load-bearing panels. The redesign process is carried out in the same way as the preliminary design process (S10). This process involves adjusting the position of the openings while considering the stress of each element. Therefore, for the redesigned load-bearing panels, the estimation process (S20) is omitted, and the analysis process (S30) and subsequent steps are performed.

[0067] <Design completed product> The load-bearing panel finally obtained through the extraction process (S40) has its openings shaped and arranged such that cracking due to the presence of the openings does not occur when the damper starts to operate. In other words, it is configured so that cracking due to the presence of the openings does not occur under any of the tensile loads, compressive loads, and shear loads acting on the load-bearing panel in the strong axis direction and weak axis direction, respectively, when the damper starts to operate.

[0068] Furthermore, the load-bearing surface material 110 equipped with grooves 153 is designed such that, even if the thickness equal to the depth of the grooves 153 is deducted from the total thickness of the surface, the shape and arrangement of the openings do not cause splitting due to the presence of the openings when the damper starts to operate.

[0069] [Design Examples] Figure 7 is a front view showing a load-bearing panel for a design example, where (a) shows the load-bearing panel before the design change and (b) shows the load-bearing panel after the design change. Figures 8 to 10 show the analysis results of the load-bearing panels shown in Figures 7(a) and (b), respectively. Figures 8(a) and (b) show the analysis results in the strong axis direction, Figures 9(a) and (b) show the analysis results in the weak axis direction, and Figures 10(a) and (b) show the analysis results related to shear. In Figures 8 to 10, elements that are expected to show relatively large stresses are circled, and the stress of those elements is clearly indicated.

[0070] The load-bearing panel 110B shown in Figure 7(a) was designed during the preliminary design phase (S10). The load-bearing panel 110B is identical to the load-bearing panel 110 shown in Figures 1 and 3, except for the positions of the openings 151 and 152. The opening 152B in the load-bearing panel 110B is an opening that was later removed due to a design change.

[0071] The load-bearing panel 110B is a 5-layer, 7-ply CLT panel with a total height of 2,672 mm, a total width of 1,500 mm, a total thickness t1 = 210 mm, and a thickness t2 = 180 mm excluding the groove depth d = 150 mm × 2. The length L of the approximate calculation target area 403 is 1,700 mm. The approximate calculation target section 402 has four openings 152 and 152B with a width length of 100 mm. The design load F input to the load input section 401 is set to 300 kN, which is the activation load of the steel plate damper 170. The standard strength of the load-bearing panel 110 used in the calculation is as follows:

[0072] [Table 1]

[0073] Furthermore, since the actual performance of the CLT panel is 4 / 3 times (1 / 0.75, the reciprocal of the 5% lower limit), the standard strength of the CLT panel that served as the basis for the load-bearing panel 110 was multiplied by 4 / 3 and used as the value for strength calculations.

[0074] The preliminary process (S20) was carried out for this load-bearing panel 110B. The bending stress for the approximate cross-section 402 is as follows: Bending moment M = FL = 300 × 1.7 = 510 [kNm] Section modulus Z = 49586792 [mm^3] Bending stress degree σ=M / Z=510×10 6 / 49586792 = 10.28 [N / mm^3] Therefore, the verification value related to bending stress was 10.28 / 14.64 = 0.702, confirming that there was no problem.

[0075] The estimated shear stress for section 402 is as follows: Shear force Q = F = 300 [kN] Cross-sectional area A=180×1500-(180×100)×4=198,000[mm^2] Shear stress τ = Q / A = 1.52 [N / mm^3] Therefore, the verified value for shear stress was 1.52 / 2.59 = 0.53, confirming that there was no problem.

[0076] Next, an analysis process (S30) and an unsuitable element extraction process (S40) were performed on the load-bearing panel 110B. The test results for the elements circled in Figures 8(a), 9(a), and 10(a) are as follows.

[0077] [Table 2]

[0078] In all cases, the test value is 1.0 or less. However, it was found that there is an element 2 with a test value of 0.86 in the strong axis direction (tensile), and for shear, there are elements 8 with a test value of 0.85 and element 9 with a test value of 0.81.

[0079] Therefore, in this example, the above elements were identified as unsuitable elements, and a redesign process (S50) was carried out. In the redesign process, the opening 152B located near the unsuitable elements was eliminated, and the load-bearing panel 110C was redesigned to include a new opening 152C, as shown in Figure 7(b).

[0080] The redesigned load-bearing panel 110C underwent an analysis process (S30) and an unsuitable element extraction process (S40). Figures 8(b), 9(b), and 10(b) show the analysis results for the load-bearing panel 110C. The following are the test results for the elements corresponding to each element in Table 2 of the load-bearing panel 110C.

[0081] [Table 3]

[0082] As a result of the redesign, the test values ​​improved. Furthermore, no non-compliant elements were found.

[0083] [Modified Embodiment] The load-bearing panel 110 does not necessarily have to have an upper slit 121 for housing the steel plate damper 170. In this case, the steel plate damper 170 is attached to the surface of the load-bearing panel 110. The shear wall 100 may be equipped with other types of dampers instead of the steel plate damper 170. That is, any damper that can absorb energy in the left-right direction (horizontal direction) may be used instead of the steel plate damper. For example, steel dampers, viscoelastic dampers, oil dampers, etc., can be used as dampers. These dampers are joined to the shear wall 110 by an appropriate method.

[0084] At least one of the upper and lower connecting members that join the load-bearing panel 110 to the beam 305 includes a damper that is displaced by shear force. In the above embodiment, the steel plate damper 170 is joined only to the upper part of the load-bearing panel 110. However, the steel plate damper 170 may be attached only to the lower part of the load-bearing panel 110, and the upper part of the load-bearing panel may be joined indirectly or directly to the upper beam 305U using a steel plate equivalent to the U-shaped steel plate 200. Alternatively, the steel plate damper 170 may be attached to both the upper and lower parts of the load-bearing panel 110.

[0085] The load-bearing panel 110 may be configured to be joined only to the column 303. In this case, at least one side of the load-bearing panel 110 in the width direction is indirectly joined to the column via a damper such as a steel plate damper 170. The other side of the load-bearing panel 110 in the width direction may be indirectly joined to the column 303 using a damper or a fixed joining member, or it may be joined directly to the column. Furthermore, the load-bearing panel 110 may be configured to be joined to both the beam 305 and the column 303.

[0086] [Summary of Embodiments, Functions, and Effects of the Invention] <First Embodiment> The load-bearing wall structure (load-bearing wall 100) according to this embodiment comprises an upper mounting portion 120 for attaching an upper beam 305U, a lower mounting portion 140 for attaching a lower beam 305L, and at least one opening 151, 152 positioned to avoid the upper and lower mounting portions and penetrating in the thickness T direction, and a perforated wooden load-bearing surface material 110 installed between the upper beam and the lower beam, an upper joining member (steel plate damper 170, T-shaped steel 190) for joining the upper mounting portion to the upper beam, and a lower joining member (U-shaped steel plate 200, base 210) for joining the lower mounting portion to the lower beam, wherein at least one of the upper joining member and the lower joining member is equipped with a damper that deforms in accordance with the positional displacement when the upper beam and the lower beam are displaced relative to each other in the longitudinal direction of each beam.

[0087] Creating openings in wood paneling results in cross-sectional loss and stress concentration, leading to a decrease in the load-bearing capacity of the panel itself. Therefore, the size and number of openings in wood paneling are severely limited. In this embodiment, the load-bearing wall structure is equipped with dampers, which reduces the shear force borne by the perforated timber load-bearing panel. As a result, even if the timber load-bearing panel has openings, the panel can perform its required function without being destroyed. According to this embodiment, it is possible to provide a load-bearing wall structure that combines the necessary load-bearing capacity with aesthetic appeal.

[0088] <Second Embodiment> The load-bearing wall structure (load-bearing wall 100) according to this embodiment is characterized in that the shape and arrangement of the openings are set so that cracking due to the presence of the openings 151 and 152 does not occur when the damper (steel plate damper 170) starts to operate. Once the damper activates under load, no further load is applied to the perforated wood load-bearing panel 110. In this embodiment, the perforated wood load-bearing panel is designed so that it does not break under the load at which the damper activates.

[0089] <Third Embodiment> In the load-bearing wall structure (load-bearing wall 100) according to this embodiment, the perforated wood load-bearing panel 110 is characterized in that it is made of CLT. Compared to other structural sheathing materials, CLT has high strength and is suitable for use as a load-bearing sheathing material with openings.

[0090] <Fourth Embodiment> In the load-bearing wall structure (load-bearing wall 100) according to this embodiment, the shape and arrangement of the openings 151 and 152 are set so that, when the damper (steel plate damper 170) starts to operate, the tensile load, compressive load, and shear load acting on the perforated wood load-bearing panel 110 in the strong axis direction and the weak axis direction, respectively, do not exceed the standard strength of the perforated wood load-bearing panel.

[0091] Once the damper activates under load, no further load is applied to the perforated wood load-bearing panel 110. In this embodiment, the perforated wood load-bearing panel is designed so that it does not break under the load at which the damper activates.

[0092] In this embodiment, CLT is used as the perforated timber load-bearing panel. The perforated timber load-bearing panel is designed so that when the load that starts the damper operation is applied to the perforated timber load-bearing panel, the tensile load, compressive load, and shear load acting on the perforated timber load-bearing panel in the strong axis direction and the weak axis direction, respectively, do not exceed the respective standard strengths of the CLT. As long as each load does not exceed the standard strength, the shape and arrangement of the openings can be freely set. When designing perforated wood load-bearing panels, for example, strength analysis using the finite element method is performed to set the shape and arrangement of the openings so that each load acting on the perforated wood load-bearing panel does not exceed the standard strength.

[0093] <Fifth Embodiment> In the load-bearing wall structure (load-bearing wall 100) according to this embodiment, the perforated wooden load-bearing panel 110 is provided with grooves 153 within its surface that do not penetrate the perforated wooden load-bearing panel in the thickness T direction, and the shape and arrangement of the openings 151 and 152 are set so that even if the thickness d of the groove depth is deducted from the entire surface of the perforated wooden load-bearing panel, splitting due to the presence of the openings does not occur when the damper (steel plate damper 170) starts to operate. According to this embodiment, calculations are simplified because grooves are ignored during the calculation. Furthermore, the result tends to be more conservative.

[0094] <Sixth Embodiment> In the load-bearing wall structure (load-bearing wall 100) according to this embodiment, one of the lower and upper connecting members is a steel plate (U-shaped steel plate 200) that rigidly connects a perforated wooden load-bearing panel 110 and a beam (lower beam 305L), and the other of the lower and upper connecting members is a steel plate damper 170 made of a steel plate comprising a beam joint 171 located at one end in the vertical direction and connected to a beam (upper beam 305U), a panel joint 175 located at the other end in the vertical direction and connected to the perforated wooden load-bearing panel, and a damper portion 181 located between the beam joint and the panel joint that deforms under shear force, wherein the damper portion is characterized by having a plurality of damper holes 182, which are elongated holes extending in the vertical direction, arranged in the left-right direction. By using steel plate dampers in load-bearing wall structures, the design can be improved. [Explanation of Symbols]

[0095] DP...Drift pin, B...Bolt, N...Nut, 100...Shear wall (Shear wall structure), 110, 110B, 110C...Perforated wood shear panel, 110a...Upper end surface, 120...Upper mounting part, 121...Upper slit, 121a...Inner surface, 121b...Rear end, 123...Pin hole, 124...Bolt hole, 125...Recess, 127...Guide rail, 140...Lower mounting part, 141...Lower slit 143...pin hole, 144...bolt hole, 145...recess, 151...opening (triangle), 152, 152B, 152C...opening (circular), 153...groove, 160...opening stopper, 161...large diameter washer, 170...steel plate damper (damper, upper joint member), 171...beam joint, 172...round hole, 175...face material joint, 176...elongated hole, 181...damper part, 182...damper hole, 183... Semicircular section, 184...Straight section, 185...Column section, 186...Narrow section, 190...T-shaped steel (upper connecting member), 191...Flange, 192...Web, 195...Splice plate, 200...U-shaped steel plate (lower connecting member), 201...Intermediate piece, 202...Slotted hole, 203...End protruding piece, 204...Round hole (for drift pin), 205...Round hole (for opening stopper), 210...Base (lower connecting member), 2 11…H-beam, 212…(lower) flange, 213…(upper) flange, 214…web, 215…reinforcement rib, 300…building, 301…frame, 303…column, 305…beam, 305U…upper beam, 305L…lower beam, 306…(lower) flange, 307…(upper) flange, 401…load input section, 402…approximate target section, 403…approximate target area, 403a…top end, 403b…bottom end

Claims

1. An upper mounting section for attaching the upper beam, a lower mounting section for attaching the lower beam, and a perforated wooden load-bearing panel installed between the upper beam and the lower beam, having at least one opening that penetrates in the thickness direction and is positioned to avoid the upper and lower mounting sections, An upper joining member that joins the upper mounting portion to the upper beam, The lower mounting portion is joined to the lower beam by a lower joining member, A load-bearing wall structure characterized in that at least one of the upper connecting member and the lower connecting member is provided with a damper that deforms in accordance with the positional displacement when the upper beam and the lower beam are displaced relative to each other in the longitudinal direction of the beams.

2. The load-bearing wall structure according to claim 1, characterized in that the shape and arrangement of the openings are set so as not to cause splitting due to the presence of the openings when the damper starts to operate.

3. The load-bearing wall structure according to claim 2, characterized in that the perforated wood load-bearing panel is made of CLT.

4. The shear wall structure according to claim 3, characterized in that the shape and arrangement of the openings are set so that, when the damper starts to operate, the tensile load, compressive load, and shear load acting on the perforated wood shear panel in the strong axis direction and the weak axis direction, respectively, do not exceed the standard strength of the perforated wood shear panel.

5. The perforated wooden load-bearing panel has grooves within its surface that do not penetrate the perforated wooden load-bearing panel in the thickness direction. The load-bearing wall structure according to claim 4, characterized in that the shape and arrangement of the openings are set so that, even if the thickness equal to the depth of the grooves is deducted from the entire surface of the perforated wood load-bearing panel, splitting due to the presence of the openings does not occur when the damper starts to operate.

6. One of the lower joining member and the upper joining member is a steel plate that rigidly joins the perforated wood load-bearing panel and the lower beam and the beam corresponding to one of the upper beams, the lower joining member and the upper joining member. The other of the lower joining member and the upper joining member is a steel plate damper made of a steel plate comprising: a beam joint portion arranged at one end in the vertical direction and joined to the lower beam and the beam corresponding to the other of the lower joining member and the upper joining member among the upper beams; a panel joint portion arranged at the other end in the vertical direction and joined to the perforated wood load-bearing panel; and a damper portion arranged between the beam joint portion and the panel joint portion and deformed by shear force, wherein the damper portion has a plurality of damper holes, which are elongated holes extending in the vertical direction, arranged in the left-right direction.

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