Wooden structural shear wall, construction method for wooden structural shear wall, method for increasing the wall coefficient of wooden structural shear wall, and gypsum-based shear surface material

Abstract

The present invention increases the wall magnification of a wooden structure load-bearing wall without additionally attaching a reinforcing material or stiffener, and without increasing the specific gravity and / or sheet thickness of a gypsum-based surface material. A gypsum-based load-bearing surface material 10 is formed from: a main material or a core material comprising a plate-like gypsum cured body which exhibits a nail-side surface resistance of 500 N or greater and which has blended therein inorganic fibers and an organic-based stiffness-improving material; and a paper member that covers at least front and back surfaces of the main material or core material. This load-bearing surface material: has a surface density that falls within a range of 6.5-8.9 kg / m2 and a compressive stiffness of 6.5 N / mm2 or greater; exhibits, in an in-plane shearing test of the load-bearing wall, an ultimate displacement (δu) greater than 20×10-3 rad and an initial stiffness (K) of 2.0 kN / 10-3 rad or greater; and raises not only the ultimate displacement but also a plasticity rate (μ) due to a reduction in yield point displacement (δv). As a result, the wall magnification and short-term standard shear stiffness (P0) of the wooden structure load-bearing wall are effectively and efficiently increased.

Description

[Technical Field]

[0001] The present disclosure relates to a wooden structural shear wall, a construction method for a wooden structural shear wall, a method for increasing the wall factor of a wooden structural shear wall, and a gypsum-based shear panel. More specifically, the present disclosure relates to a wooden structural shear wall, a construction method for a wooden structural shear wall, a method for increasing the wall factor of a wooden structural shear wall, and a gypsum-based shear panel that are configured to increase the wall factor without relying on increasing the maximum strength of the panel itself, increasing the ultimate displacement, or providing additional reinforcement or stiffening materials. [Background technology]

[0002] Generally, construction methods for wooden buildings are broadly divided into wooden frame construction and wooden frame wall construction. Due to the impact of recent large-scale earthquakes, research into the seismic resistance of wooden buildings has been attracting particular attention in Japan in recent years. As described in Patent Document 1 (International Publication WO2019 / 203148A1), in architectural design practice in Japan, the effective frame length of a shear wall (the length of the wall in the architectural plan) is generally used as an indicator of the strength of a wooden building against short-term horizontal loads (seismic force, wind pressure, etc.). A wall factor appropriate to the structure of the shear wall is used to calculate the frame length. The wall factor is an indicator of the seismic performance or strength performance of the shear wall, and the higher the value, the greater the seismic strength. A wall structure with a high wall factor is advantageous in terms of improving the design flexibility and seismic resistance of the entire building.

[0003] The wall multipliers for general-purpose wooden shear walls, which have been used in Japan for many years, are specified in Article 46 of the Building Standards Act Enforcement Order, Ministry of Construction Notification No. 1100 (June 1, 1981), and Ministry of Land, Infrastructure, Transport and Tourism Notification No. 1541 (October 15, 2001). However, for many of the shear walls that do not fall under these general-purpose wall structures, the wall multiplier must be determined based on the Minister of Land, Infrastructure, Transport and Tourism's certification as stipulated in Article 4, Section 4, Table 1 (viii) of the same Act. Therefore, the wall multipliers for the relatively large number of wooden shear walls constructed in recent years must be determined based on performance tests conducted by designated performance evaluation organizations. The test methods for these performance tests are described in detail in the "Wooden Shear Walls and Their Multipliers: Performance Testing and Evaluation Service Manual" published by each testing and inspection organization.

[0004] As described in many documents, such as "Wooden Shear Walls and Their Multipliers: Performance Testing and Evaluation Procedures," the performance test to determine the wall multiplier for wooden shear walls is the in-plane shear test. In this test, a specified horizontal load is repeatedly applied to a shear wall specimen, and the relationship between the horizontal load and the shear deformation angle is determined.

[0005] Figure 1 shows an example of a load-deformation curve obtained by an in-plane shear test as an envelope curve (shown by a solid line). Figure 1 also shows a linear graph in which the envelope curve of the load-deformation curve is converted into the load-deformation characteristic curve of a perfectly elastoplastic model, shown by a dashed-dotted line. The perfectly elastoplastic model consists of a linear function line (Y = KX) in the linear elastic region that indicates the initial stiffness K, and a line (Y = Pu) in the plastic deformation region (plastic region) that extends parallel to the X-axis from the yield point σs. The yield point σs indicates the elastic limit. The initial stiffness K is a coefficient that indicates the slope of the linear function line (Y = KX) in the elastic region. The area on the diagram enclosed by the envelope curve, the X-axis, and the line segment X = δu is equal to the area on the diagram enclosed by the X-axis, the line segments Y = KX, Y = Pu, and X = δu. The method of converting the envelope into a fully elastic-plastic model is described in many documents, such as "Wooden Shear Walls and Their Magnification Factors - Performance Testing and Evaluation Procedure Manual," and is also well-known in the field of material mechanics, so further explanation will be omitted here.

[0006] Figure 1 shows the maximum strength Pmax, the 0.8Pmax load drop region, the ultimate strength Pu, the yield strength Py, the ultimate displacement δu, the yield point displacement δv, and the yield displacement δy. The ultimate displacement δu and the yield point displacement δv are the deformation angle values ​​at the 0.8Pmax load drop region and the yield point σs, respectively. The yield displacement δy is the deformation angle value when the yield strength Py is reached. The ductility factor μ is the value of the ultimate displacement δu / yield point displacement δv.

[0007] As described in many technical documents, such as "Allowable Stress Design for Wooden Frame Construction Houses [1] (2017 Edition)" on pages 63 and 300 (Non-Patent Document 1), the wall factor is calculated by calculating the short-term allowable shear strength (Pa) based on the strengths Pmax, Pu, Py and displacements δu, δv, δy specified by the perfectly elasto-plastic model shown in Figure 1, and dividing this by the specified strength (wall length L (m) × 1.96 (kN / m)). In other words, the wall factor is an indexed value obtained by dividing the short-term allowable shear strength (Pa) by this reference value (1.96L).

[0008] To explain this further, in principle, when calculating the wall factor, the smallest of the four types of strength values ​​below is specified as the short-term standard shear strength (P0), and the value is calculated by multiplying the short-term standard shear strength (P0) by a specified reduction coefficient (α) (a coefficient that evaluates the factors that reduce strength). Generally, in the case of gypsum-based shear facings, the strength of (1) or (2) below, i.e., the yield strength (Py) or ultimate strength (corrected value) (Pu'), shows the smallest value. Note that the following strength values ​​(Py, Pu, Pmax) are calculated by multiplying each measured value by a variation coefficient (β). (1) Yield strength (Py) (2) The value of ultimate strength (Pu) corrected based on the ductility factor (μ) (hereinafter referred to as "ultimate strength (corrected value) (Pu')"). (3) 2 / 3 of the maximum strength (Pmax) (4) Strength when shear deformation angle = 1 / 120 rad (unloaded or loaded type)

[0009] "Structural gypsum board" is known as a gypsum-based surface material suitable for use as a bearing surface material for wooden structural shear walls. "Structural gypsum board" is a gypsum-based surface material that enhances the lateral nail resistance of "reinforced gypsum board" based on the applicant's technology described in Patent Publication No. 5642948 (Patent Document 2). The lateral nail resistance is the shear strength or shear strength of the nailed portion of the surface material measured by the lateral nail resistance test specified in JIS A 6901. Since the lateral nail resistance is described in relatively detail in PCT / JP2021 / 14227 (Patent Document 3) filed by the applicant, further detailed explanation will be omitted. However, the lateral nail resistance is a physical property proposed by the applicant in Patent Document 2 as a strength evaluation factor for gypsum-based bearing surface materials, and is a strength factor that the applicant has particularly focused on in recent years.

[0010] Structural gypsum board is a gypsum-based surface material that has improved overall strength as a bearing surface material compared to (ordinary) gypsum board, and improved lateral nail resistance compared to reinforced gypsum board. Currently, structural gypsum board is specified in JIS A 6901 as a gypsum-based surface material with a lateral nail resistance of 750N or more (Type A) or 500N or more (Type B). Wood-structure shear walls using structural gypsum board as a bearing surface material exhibit a relatively high wall ratio compared to wood-structure shear walls using (ordinary) gypsum board or reinforced gypsum board as a bearing surface material. On the other hand, like reinforced gypsum board, structural gypsum board requires a thickness of 12.5mm or more and a specific gravity of 0.75 or more. For this reason, wood-structure shear walls to which structural gypsum board is fixed have a strength of at least approximately 9.4kg / m 2 The surface density or surface weight (mass of load-bearing surface material per unit area of ​​wall) is required.

[0011] Generally, the short-term standard shear strength (P0) of a bearing wall made of structural gypsum board fastened to a wooden wall substrate with fasteners is determined by the yield strength (Py) of the four types of strength values ​​mentioned above (P0 = β x Py). As mentioned above, the wall factor is the short-term standard shear strength (P0) multiplied by the reduction coefficient (α) and divided by the specified strength (1.96L). Therefore, the wall factor of a bearing wall made of structural gypsum board fastened to a wooden wall substrate with fasteners is proportional to the yield strength (Py).

[0012] Patent Document 3 describes a gypsum-based bearing surface material that provides a bearing wall with a short-term standard shear strength (P0) equivalent to that of structural gypsum board, but has a lower surface density than structural gypsum board. The gypsum-based surface material described in Patent Document 3 is composed of a main material or core material made of a plate-shaped gypsum hardened body that is blended with inorganic fiber and an organic strength-improving material so as to exhibit a nail lateral resistance of 500 N or more, and a paper member that covers at least the front and back surfaces of the main material or core material, and has a shear strength of 6.5 to 8.9 kg / m 2 The gypsum-based facing material of Patent Document 3 has an areal density or areal weight (hereinafter referred to as "areal density") within the range. The gypsum-based facing material of Patent Document 3 can provide a relatively high wall coefficient to a shear wall even when the board thickness is less than 12 mm. This gypsum-based facing material is a shear wall facing material (hereinafter referred to as "low-density gypsum-based shear wall facing material") that was developed with the intention of reducing the surface density and weight of the facing material compared to conventional gypsum-based shear wall facing materials such as structural gypsum board, while suppressing a decrease in yield strength with a relatively high nail lateral resistance, and is extremely advantageous in practical terms from the viewpoint of achieving both the desired strength as a wooden structural shear wall, its light weight, ease of construction, etc.

[0013] Generally, the short-term standard shear strength (P0) of a bearing wall in which low-density gypsum-based bearing surface material is fastened to a wooden structural wall substrate with fasteners is such that the ultimate strength (corrected value) (Pu') is the smallest value among the above four types of strength values. Therefore, the short-term standard shear strength (P0) and wall factor for calculating the wall magnification factor are proportional to the ultimate strength (corrected value) (Pu'), unlike structural gypsum board. As described in Patent Document 3, an unexpected effect of low-density gypsum-based bearing surface material is that the toughness and deformation followability that the gypsum-based bearing surface material potentially possesses become apparent due to the decrease in surface density, and as a result, the ultimate displacement (δu) of the bearing wall increases to 20 x 10 -3 As a result of obtaining an ultimate displacement (δu) greater than rad, a bearing wall formed by fixing the low-density gypsum-based bearing surface material of Patent Document 3 to a wooden structural wall substrate exhibits an ultimate strength (corrected value) (Pu') greater than 7.6 kN. Thus, as described above, the low-density gypsum-based bearing surface material exhibits a strength equivalent to that of structural gypsum board, despite having a reduced surface density compared to structural gypsum board.

[0014] The ultimate strength (corrected value) (Pu') is a value calculated using the formula below based on the ultimate strength (Pu) and the plasticity factor (μ), and the short-term standard shear strength (P0) is a value calculated using the formula below based on the ultimate strength (corrected value) (Pu') and the coefficient of variation (β) of its measurement value. Pu' = Pu × 0.2 × (2μ-1) 1 / 2 P0 = β × Pu'

[0015] To further increase the short-term standard shear strength (P0) and wall factor of such low-density gypsum-based shear walls, it is necessary to further increase the wall's ultimate strength (corrected value) (Pu'), as is clear from the above equation. Increasing the ultimate strength (corrected value) (Pu') requires increasing the wall's ultimate strength (Pu) and / or ductility factor (μ). The ultimate strength (Pu) generally increases with an increase in the maximum load (Pmax) that the shear wall can withstand in an in-plane shear test, i.e., the maximum strength (Pmax) of the shear wall. Therefore, a method for increasing the wall factor is envisioned that increases the maximum strength (Pmax) and, therefore, the ultimate strength (Pu). However, as will be discussed later, it is currently extremely difficult to further increase the maximum strength (Pmax) while maintaining the lightweight nature of low-density gypsum-based shear walls. Another possible method is to increase the wall factor, which increases the value of the plasticity factor (μ) and indirectly increases the ultimate strength (Pu), as described in Patent Document 3. However, this requires further increasing the value of the ultimate displacement (δu) of the shear wall, which, as will be described later, is also extremely difficult under the current circumstances.

[0016] In response to this, Patent Document 1 describes a method of reinforcing face panels, in which reinforcing or stiffening materials such as metal plates are placed in nailed sections to prevent damage or fracture of the nailed sections, as a measure to increase the ultimate strength (corrected value) (Pu') of a shear wall and improve the wall factor. However, with wooden shear walls that use such reinforcing or stiffening materials, it is thought that it will be possible to build wooden shear walls that exhibit a relatively high wall factor by improving the toughness and deformation compliance of the shear face panels and increasing the ultimate strength (corrected value) (Pu') without relying on an increase in the maximum load that the face panel can withstand in the above-mentioned performance tests.

[0017] In this specification, the term "gypsum-based load-bearing surface material" is used to include not only the (ordinary) gypsum board, reinforced gypsum board, and structural gypsum board specified in JIS A 6901 (gypsum board products), but also gypsum-based surface materials in which the outer surface or outer layer of a gypsum core portion (core material portion) made primarily of gypsum is covered with a paper material such as gypsum board base paper, such as the above-mentioned low-density gypsum-based load-bearing surface material (Patent Document 3) and the gypsum-based load-bearing surface material described in Patent Publication No. 6412431 (Patent Document 4). [Prior art documents] [Patent documents]

[0018] [Patent Document 1] International Publication WO2019 / 203148A1 [Patent Document 2] Patent No. 5642948 Publication [Patent Document 3] PCT / JP2021 / 14227 Specification and Drawings [Patent Document 4] Patent No. 6412431 Publication [Non-patent literature]

[0019] [Non-Patent Document 1] Allowable Stress Design of Wooden Frame Construction Houses [1] (2017 Edition), pages 63 and 300 Summary of the Invention [Problem to be solved by the invention]

[0020] According to the shear wall structure (Patent Document 1) that uses the above-mentioned reinforcing or stiffening materials to increase the ultimate strength (corrected value) (Pu'), a process for additionally attaching the reinforcing or stiffening materials to the surface of the shear wall must be added to the panel manufacturing process, or such a process must be additionally performed during the construction of the wooden shear wall. This type of process can complicate the manufacturing process of gypsum-based panel materials or can be a factor that deteriorates the workability of construction work.

[0021] In contrast, to further improve the wall factor of a wooden shear wall using the low-density gypsum-based shear face material without relying on such reinforcement or stiffening materials, it is necessary to further increase the ultimate strength (Pu) and / or plasticity factor (μ) of the shear wall, thereby further increasing the ultimate strength (corrected value) (Pu') of the shear wall, as mentioned above. Since the ultimate strength (Pu) generally increases with an increase in the maximum strength (Pmax) of a shear wall, one possible method for increasing the wall factor is to increase the maximum strength (Pmax) and thereby the ultimate strength (Pu). However, there is a concern that increasing the maximum strength (Pmax) will decrease the plasticity factor (μ), which will in turn decrease the ultimate strength (corrected value) (Pu'). Furthermore, an increase in the maximum strength (Pmax) is usually accompanied by an increase in the areal density of the shear face material. However, since gypsum-based shear panels generally have a weight of more than 20 kg for their standard dimensions (approximately 910 mm wide and 3030 mm high), and considering the actual work that construction workers do by hand to fix the shear panels to the wall substrate of wooden shear walls, it is considered that increasing the surface density of the shear panels is not practically desirable from the perspective of the workability of wooden shear walls. In other words, it is actually extremely difficult to substantially increase the maximum strength (Pmax) without substantially decreasing the ductility factor (μ) and ultimate strength (corrected value) (Pu') and without substantially increasing the surface density.

[0022] On the other hand, based on the technology described in Patent Document 3, it may theoretically be possible to further increase the ultimate displacement (δu) of a bearing wall, thereby increasing the value of the ductility factor (μ), and thereby increasing the ultimate strength (Pu). However, there is a limit to how much the ultimate displacement (δu) can be increased by measures such as reducing areal density. Moreover, at present, there is no knowledge of an effective means for further increasing only the value of the ultimate displacement (δu) without significantly reducing the nail lateral resistance, maximum strength (Pmax), or yield strength (Py). Therefore, at present, it is extremely difficult to further increase the value of the ultimate displacement (δu) and thereby increase the value of the ductility factor (μ).

[0023] The present disclosure has been made in consideration of the above circumstances, and its purpose is to provide a gypsum-based shear surface material for wooden structural shear walls that, in the above-mentioned low-density gypsum-based shear surface material that has a reduced surface density while maintaining a relatively high nail lateral resistance, can increase the ultimate strength (corrected value) (Pu') of the shear wall and increase the short-term standard shear strength (P0) and wall factor of the shear wall without additionally attaching reinforcing or stiffening materials, without increasing the surface density (specific gravity and / or board thickness) of the surface material itself, and without further increasing the ultimate displacement (δu) of the shear wall.

[0024] Another object of the present disclosure is to provide a load-bearing wall structure for a wooden building using such a gypsum-based surface material as a load-bearing surface material, and a construction method for a wooden structure load-bearing wall.

[0025] The present disclosure further aims to provide a method for increasing the wall factor of a wooden structural shear wall, which can increase the ultimate strength (corrected value) (Pu') of a shear wall using the above-mentioned low-density gypsum-based shear surface material, and can increase the short-term standard shear strength (P0) and wall factor of the shear wall, without relying on the action of reinforcing or stiffening by reinforcing or stiffening materials additionally provided on the gypsum-based surface material, without relying on an increase in the surface density of the gypsum-based surface material itself, and without further increasing the ultimate displacement (δu) of the shear wall. [Means for solving the problem]

[0026] In order to achieve the above object, the present disclosure provides a gypsum-based load-bearing surface material that is fastened to a wooden structural wall substrate of a wooden framework construction method or a wooden frame wall construction method by a fastener, It is composed of a main material or core material made of a plate-shaped gypsum hardened body and a paper member covering at least the front and back surfaces of the main material or core material, The surface density, specified as the mass per unit area of ​​the wall, is 6.5 to 8.9 kg / m 2 and having an areal density in the range of Nail side resistance of 500N or more and at least 6.5N / mm 2 It has a compressive strength of Inorganic fibers and organic strength-improving materials are blended into the main material or core material, The present invention provides a gypsum-based shear wall material that allows a shear wall to exhibit a corrected value (Pu') of the ultimate strength (Pu) of 7.7 kN or more, as the corrected value (Pu') of the ultimate strength (Pu) determined by an in-plane shear test using a shear wall specimen with a length of 1.82 m, which is formed by fastening the shear wall material to the wooden structural wall base with fasteners.

[0027] According to the gypsum-based bearing surface material of the present disclosure, inorganic fibers and organic strength improving materials are mixed to ensure the minimum physical properties required for a gypsum-based bearing surface material (nail lateral resistance: 500 N or more), while the surface density of the surface material is rather reduced to a relatively low value (6.5 to 8.9 kg / m 2 In the following description of this specification, "minimum physical properties as a gypsum-based load-bearing surface material" means a nail lateral resistance of 500 N or more.

[0028] The above surface density values ​​(6.5 to 8.9 kg / m 2 ) is the surface density of conventional gypsum-based load-bearing surface materials such as structural gypsum boards (approximately 9.4 kg / m 2 ) is a value significantly smaller than the above. Such an areal density allows the specific gravity and / or thickness of the gypsum-based load-bearing surface material to be reduced, thereby reducing the weight of the load-bearing wall or reducing the wall thickness. On the other hand, such a reduction in areal density is in conflict with the conventional wall factor increase method that increases the short-term standard shear strength (P0) and wall factor of the load-bearing wall (i.e., the conventional wall factor increase method that increases the maximum strength (Pmax) by increasing the specific gravity and / or thickness, thereby increasing the short-term standard shear strength (P0)). However, as described in Patent Document 3, if the surface density is reduced while maintaining the minimum physical properties required for a gypsum-based shear surface material (nail lateral resistance: 500 N or more), the toughness and deformation compliance inherent in the gypsum-based shear surface material become apparent in the plastic region, and as a result, the ultimate displacement (δu) and plasticity factor (μ) of the shear wall actually increase, which increases the ultimate strength (corrected value) (Pu') of the shear wall.This makes it possible to increase the short-term standard shear strength (P0) and wall factor without necessarily increasing the maximum strength (Pmax).

[0029] According to the present disclosure, the main material or core material has a strength of 6.5 to 8.9 kg / m 2 The concrete contains a predetermined amount of inorganic fibers and organic strength-improving materials to exhibit a nail side resistance of 500 N or more at an areal density within this range. By maintaining a nail side resistance of 500 N or more, a desired yield strength can be maintained despite a decrease in areal density. The amount of inorganic fibers to be blended is 0.3 to 5 parts by weight, preferably 2 to 4 parts by weight, per 100 parts by weight of calcined gypsum. Examples of inorganic fibers to be blended include glass fibers and carbon fibers. When glass fibers are used, glass fibers having a diameter of 5 to 25 μm and a length of 2 to 25 mm can be suitably used.

[0030] Furthermore, the inventors have found through many experiments that the initial stiffness (K) of a bearing wall increases with an increase in the compressive strength of a gypsum-based bearing surface material. Based on this finding, and as a result of extensive research, they have found that the compressive strength of a gypsum-based bearing surface material increases to 6.5 N / mm 2 It was found that increasing the initial stiffness (K) of the shear wall to the above value would increase the yield point displacement (δv) without significantly reducing the ultimate displacement (δu) of the shear wall, thereby enabling a relatively large increase in the plasticity factor (μ), leading to the present disclosure.

[0031] That is, according to the present disclosure, the compressive strength of the gypsum-based bearing surface material is set to 6.5 N / mm 2 Increase the initial stiffness (K) of the shear wall to, for example, 2.0 kN / 10 -3 rad or more, thereby increasing the value of the yield point displacement (δv) to, for example, 7.2 × 10 -3 By reducing the value to a value below rad, coupled with the relatively high value of ultimate displacement (δu), the value of the ductility factor (μ) can be increased relatively significantly, and as a result, it is relatively easy to ensure a value of 7.7 kN or more as the ultimate strength correction value (Pu').

[0032] Incidentally, in the case of a bearing wall using low-density gypsum-based bearing surface material in Patent Document 3, the initial stiffness (K) is 2.0 kN / 10 -3 Values ​​less than rad (e.g., 1.9kN / 10-3 rad). The structural gypsum board described above is a gypsum-based sheathing surface material that was developed to increase the lateral nail resistance as desired, focusing on a strength factor known as lateral nail resistance, in order to prevent tearing failure of the gypsum-based sheathing surface material due to changes in the relative position between the gypsum-based sheathing surface material and fasteners that can occur during vibration. The low-density gypsum-based sheathing surface material of Patent Document 3 is intended to increase the ductility factor (μ) and ultimate strength (corrected value) (Pu') by reducing the surface density while maintaining the desired lateral nail resistance, thereby enhancing the toughness and deformation compliance of the gypsum-based sheathing surface material in the plastic region. However, neither of these works focuses on or considers the compressive strength of the gypsum-based sheathing surface material or the initial stiffness that occurs in the elastic region as strength-improving factors, nor does it examine or study the structural relationship between the initial stiffness of a shear wall and the compressive strength of the gypsum-based sheathing surface material.

[0033] On the other hand, according to experiments conducted by the present inventors, increasing the areal density can increase the compressive strength as desired. However, increasing the areal density not only increases the weight of the facing material but also tends to reduce the ultimate displacement. Therefore, it is desirable to increase the compressive strength to an appropriate value primarily by utilizing the compressive strength-increasing effect of the organic strength-enhancing material. In other words, in the present disclosure, the compressive strength is set as desired primarily by setting an appropriate areal density and utilizing the compressive strength-increasing effect of the organic strength-enhancing material. The amount of the organic strength-enhancing material to be blended is 0.3 to 15 parts by weight, preferably 1 to 13 parts by weight, per 100 parts by weight of calcined gypsum. Suitable examples of organic strength-enhancing materials include starch, polyvinyl acetate, polyvinyl alcohol, and polyacrylic. Both unmodified and modified starches can be used as starches. Examples of modified starches include starches that have been physically, chemically, or enzymatically treated. Suitable examples of physically treated starches include pregelatinized starch. Suitable chemically treated starches include oxidized starch, phosphated starch, urea phosphated starch, hydroxypropylated phosphate cross-linked starch, hydroxyethylated starch, hydroxypropylated starch, cationized starch, and acetylated starch.

[0034] Factors known to vary the compressive strength of gypsum-based bearing surface materials include the mixing condition of the gypsum slurry (mixing time, mixing temperature, etc.), the type and amount of impurities contained in the gypsum raw material, the cross-sectional properties, density, and uniformity of the gypsum core, the amount, size, and dispersion of air bubbles contained in the gypsum core, the moisture content or water content of the gypsum core, and the specific gravity of the gypsum core. While these factors may be used as control factors to increase or decrease compressive strength, they are not only closely related to the manufacturing conditions (type of gypsum raw material, type and amount of additives such as foaming agents, temperature of the mixing water, air temperature, humidity, etc.), but are also related to the overall quality of the gypsum core, and are often associated with relatively low areal densities (6.5 to 8.9 kg / m). 2 Within the range of areal density, the desired compressive strength (6.5N / mm 2 The organic strength-enhancing agent is not a controlling factor of properties that can be used specifically for a specific application, such as imparting a desired compressive strength (compressive strength of 500 N or more) to a gypsum-based load-bearing facing material and, moreover, working in conjunction with inorganic fibers, imparting a desired nail side resistance (nail side resistance of 500 N or more) to the gypsum-based load-bearing facing material. On the other hand, the organic strength-enhancing agent can be used specifically for such an application, and, moreover, can be added to the gypsum slurry during the manufacturing process, providing a realistic and effective means for increasing the compressive strength of the gypsum core.

[0035] Preferably, the bearing surface material has an initial stiffness (K) of 2.0 kN / 10 as measured by an in-plane shear test. -3 rad or more, or the yield point displacement (δv) of the shear wall measured by the in-plane shear test is 7.2 × 10 -3 rad or less, or the initial stiffness (K) must be 2.0 kN / 10 -3 rad or more and the yield point displacement (δv) is 7.2 × 10 -3 rad or less, 6.5N / mm 2 For example, in the gypsum-based bearing surface material according to the present disclosure, the yield point displacement (δv) is 6.0 × 10 -3 rad, initial stiffness (K)=2.5kN / 10 -3 rad, ultimate strength Pu = 15.0 kN, ultimate displacement (δu) = 30 × 10 -3rad, plasticity factor (μ) = 5.0, and dispersion coefficient β = 1.0, the ultimate strength (corrected value) (Pu') is 9.0 kN. In contrast, if we assume that the initial stiffness (K) is 1.9 kN / 10, as in the case of the low-density gypsum-based bearing surface material mentioned above, -3 rad(<2.0kN / 10 -3 rad), the ultimate strength Pu = 15.0, the ultimate displacement (δu) = 30 × 10 -3 rad, and even if the variation coefficient β is 1.0, the yield point displacement (δv) is 7.8×10 -3 rad, ductility factor (μ) = 3.8, and the ultimate strength (corrected value) (Pu') is only about 7.7 kN. In other words, by increasing the compressive strength of the bearing face material and increasing the initial stiffness (K), the ultimate strength (corrected value) (Pu') can be increased relatively significantly, and the short-term standard shear strength (P0) and wall factor can also be increased relatively significantly.

[0036] In the present disclosure, the compressive strength is preferably 7.5 to 13.0 kN / mm 2 A value in the range of 8.0 kN / mm 2 In the present disclosure, the initial stiffness is preferably set to a value equal to or greater than 2.2 kN / 10 -3 rad~4.0kN / 10 -3 rad, more preferably 2.4 kN / 10 -3 Furthermore, according to the present disclosure, the yield displacement (δv) is preferably set to a value of 3.5×10 -3 rad~7.2×10 -3 rad, more preferably 6.5×10 -3 Preferably, a bearing wall provided with a gypsum-based bearing surface material according to the present disclosure has a plasticity factor (μ) measured by an in-plane shear test of 4.2 or more and 10.0 or less, preferably 4.3 or more, and an ultimate displacement (δu) of the bearing wall measured by an in-plane shear test of 20×10 -3 A value greater than rad, preferably 22 x 10 -3rad or greater, and the yield strength (Py) measured by in-plane shear testing is 7.7 kN or greater, greater than the ultimate strength (corrected value) (Pu'), preferably 8.0 kN or greater. Experiments by the inventors have shown that as the initial stiffness (K) increases, the yield strength (Py) also tends to increase. Therefore, as with the low-density gypsum-based shear panels mentioned above, the yield strength (Py) is generally greater than the ultimate strength (corrected value) (Pu'). The ultimate displacement (δu) of a shear wall is an index of the wall's toughness and deformation followability in the plastic range. According to the "Wooden Shear Walls and Their Ratios: Performance Testing and Evaluation Practice Manual," if the load does not decrease and an ultimate displacement value cannot be obtained in an in-plane shear test even when the load exceeds 1 / 15 rad, the ultimate displacement (δu) is set to 1 / 15 rad. Therefore, the maximum value of the ultimate displacement (δu) is 1 / 15rad (66.7×10 -3 rad).

[0037] Thus, with a bearing wall using the gypsum-based shear facing material of the present disclosure, while maintaining the minimum physical properties required for a gypsum-based shear facing material, not only is the reduction in areal density improving the toughness and deformation compliance of the gypsum-based shear facing material in the plastic region, thereby increasing the ultimate shear strength (corrected value) (Pu'), but also increasing the initial stiffness (K) and decreasing the yield point displacement (δv) to further increase the ultimate shear strength (corrected value) (Pu'). This allows for a relatively large increase in the short-term standard shear strength (P0) and wall ratio of the bearing wall without the need for additional reinforcement or stiffening materials or an increase in the areal density of the gypsum-based shear facing material. Furthermore, like structural gypsum board and the aforementioned low-density gypsum-based shear facing material, the above-mentioned shear facing material has at least the front and back surfaces of the main material or core material covered with paper members, making it easy to manufacture on a conventional gypsum board production line. Preferably, the gypsum-based load-bearing facing material of the present disclosure has a laminated structure in which the surface or surface layer of the core material is covered with gypsum board base paper. Note that the "front and back surfaces" refer to the front and back surfaces of the facing material excluding the end faces or side surfaces of the edge and side edges (i.e., the four outer edges) of the facing material.

[0038] Preferably, the thickness of the gypsum-based bearing surface material is set to a value of 7.5 mm or more and less than 12 mm (more preferably, a value of 8.5 mm or more and 10 mm or less), for example, 9.5 mm or 9.0 mm. Gypsum-based bearing surface materials with such a thickness are advantageous in reducing the wall thickness of wooden structural bearing walls compared to structural gypsum boards that require a thickness of 12 mm or more. Optionally, the gypsum hardened body has a nail lateral resistance of 980 N or less.

[0039] Preferably, the gypsum-based bearing surface material has an ultimate displacement (δu) of the bearing wall measured by an in-plane shear test using a bearing wall specimen having a wall length of 1.82 m of 24×10 -3 rad or more (preferably 26×10 -3 The relatively high value of the ultimate displacement (δu) increases the initial stiffness (K) of the shear wall and decreases the yield point displacement (δv), which in turn increases the ductility factor (μ), making it extremely advantageous in increasing the short-term shear strength (P0) and wall factor.

[0040] More preferably, the specific gravity of the gypsum-based bearing face material is set to a value within the range of 0.65 to 0.96, preferably within the range of 0.7 to 0.9 (even more preferably within the range of 0.7 to 0.8). A gypsum-based bearing face material with such a specific gravity has a board thickness of less than 12 mm but a specific gravity of 1.0 or more, and therefore can be made lighter than an embodiment of the gypsum-based bearing face material of Patent Document 4, which has a relatively heavy weight (for example, "EX Board" (product name) manufactured by Yoshino Gypsum Co., Ltd.), and is therefore advantageous in reducing the weight of wooden bearing walls or improving the workability of wooden bearing walls or the workability of their construction.

[0041] In a preferred embodiment of the present disclosure, the core material (gypsum core portion) of the gypsum-based load-bearing facing material contains an organopolysiloxane compound as a load-bearing deterioration inhibitor that prevents load-bearing deterioration. This type of load-bearing facing material, like the gypsum-based load-bearing facing material described in Patent Document 4, can be applied to the exterior wall surface of a wooden exterior wall.

[0042] The present disclosure also provides a wooden structural shear wall having a structure in which the above-mentioned gypsum-based shear face material is fastened to a wooden structural wall substrate of a wooden frame construction method or a wooden framework wall construction method with fasteners such as nails, screws, etc. The present disclosure further provides a wooden structural shear wall construction method, characterized in that the above-mentioned gypsum-based shear face material is fastened to a wooden structural wall substrate of a wooden frame construction method or a wooden framework wall construction method with the above-mentioned fasteners.

[0043] This type of wooden shear wall and its construction method allows the areal density of the gypsum-based shear wall to be reduced by reducing its specific gravity and / or board thickness, thereby reducing the wall's weight or wall thickness. Furthermore, as mentioned above, this type of wooden shear wall not only improves the toughness and deformation compliance (in the plastic region) of the gypsum-based shear wall by reducing its density, thereby increasing the ultimate displacement (δu), but also increases the initial stiffness (K) of the shear wall due to the increased compressive strength of the gypsum-based shear wall, thereby reducing the yield displacement (δv). As a result, the relatively small yield displacement (δv) and the relatively large ultimate displacement (δu) combine to produce a relatively large increase in the ductility factor (μ), making it relatively easy to achieve an ultimate strength (corrected value) (Pu') of 7.7 kN or more for the wooden shear wall.

[0044] From another perspective, the present disclosure provides a method for increasing the wall coefficient of a wooden structural shear wall, which is constructed by fastening a gypsum-based shear face material to a wooden structural wall substrate of a wooden frame construction method or a wooden frame wall construction method with fasteners, The load-bearing surface material is composed of a main material or core material made of a plate-shaped gypsum hardened body and a paper member covering at least the front and back surfaces of the main material or core material, The surface density of the load-bearing surface material, specified as the mass per unit area of ​​the wall, is set to 6.5 to 8.9 kg / m 2 and nail side resistance of 500N or more and 6.5N / mm 2 It exhibits a compressive strength of more than 100%, and inorganic fibers and organic strength-improving materials are blended into the main material or core material. A method for increasing the wall factor is provided, characterized in that a corrected value (Pu') of the ultimate strength (Pu) of 7.7 kN or more is obtained by using a shear panel as the corrected value (Pu') of the ultimate strength (Pu) obtained by an in-plane shear test using a shear wall specimen with a wall length of 1.82 m.

[0045] Preferably, the bearing surface material has an initial stiffness (K) of 2.0 kN / 10 as measured by an in-plane shear test. -3 rad or more, or the yield point displacement (δv) of the shear wall measured by the in-plane shear test is 7.2 × 10 -3 rad or less, or the initial stiffness (K) must be 2.0 kN / 10 -3 rad or more and the yield point displacement (δv) is 7.2 × 10 -3 rad or less, 6.5N / mm 2 The compressive strength is preferably 7.5 to 13.0 kN / mm 2 A value in the range of 8.0 kN / mm 2 It can be set to a value greater than or equal to 1.

[0046] The initial stiffness is preferably 2.2 kN / 10 -3 rad~4.0kN / 10 -3 rad, more preferably 2.4 kN / 10 -3 The yield displacement (δv) can be set to a value of 3.5×10 -3 rad~7.2×10 -3 rad, more preferably 6.5×10 -3 Preferably, in a bearing wall provided with the gypsum-based bearing surface material, the plasticity factor (μ) measured by an in-plane shear test is 4.2 or more and 10.0 or less, preferably 4.3 or more, and the ultimate displacement (δu) of the bearing wall measured by an in-plane shear test is 20×10 -3 A value greater than rad, preferably 22 x 10 -3A value of 7.7 kN or more is obtained, and the yield strength (Py) measured by an in-plane shear test is 7.7 kN or more, which is greater than the above-mentioned ultimate strength (corrected value) (Pu'), preferably 8.0 kN or more.

[0047] Preferably, the thickness of the gypsum-based bearing surface material is set to a value of 7.5 mm or more and less than 12 mm (more preferably, a value of 8.5 mm or more and 10 mm or less), for example, 9.5 mm or 9.0 mm.More preferably, the specific gravity of the gypsum-based bearing surface material is set to a value of 0.65 or more and 0.96 or less, preferably a value of 0.7 or more and 0.9 or less (more preferably, a value of 0.7 or more and 0.8 or less). [Effects of the Invention]

[0048] The gypsum-based shear facing material of the present disclosure improves the toughness and deformation compliance of the gypsum-based shear facing by reducing the areal density, and in a shear wall formed by fastening this shear facing material to a wooden wall substrate with fasteners, the initial stiffness (K) is increased, reducing the yield displacement (δv), thereby increasing the ultimate strength (corrected value) (Pu') and increasing the short-term standard shear strength (P0) and wall magnification factor. The gypsum-based shear facing material of the present disclosure can be effectively used as a shear facing material to further increase the short-term standard shear strength (P0) and wall magnification factor without increasing the wall thickness or weight, particularly for shear walls whose ultimate displacement (δu) is difficult to increase easily or that are already capable of exerting an ultimate displacement (δu) close to the upper limit. Thus, according to the present disclosure, in the aforementioned low-density gypsum-based bearing face material, which has a reduced areal density while maintaining a relatively high nail lateral resistance, it is possible to further increase the short-term standard shear strength (P0) and wall ratio of the bearing wall without additionally attaching reinforcing or stiffening materials, without increasing the areal density (specific gravity and / or board thickness) of the gypsum-based bearing face material, and without further increasing the value of the ultimate displacement (δu). Moreover, because the gypsum-based bearing face material of the present disclosure has at least the front and back surfaces of the main material or core material covered with paper members, it can be easily manufactured on a conventional gypsum board manufacturing line.

[0049] Furthermore, according to the shear wall structure of the present disclosure, by using such gypsum-based shear face materials as shear face materials in wooden structural shear walls, the short-term standard shear strength (P0) and wall factor can be effectively increased, and by reducing the surface density of the gypsum-based shear face materials, the weight of the shear wall can be reduced or the wall thickness can be reduced.

[0050] Furthermore, according to the construction method for wooden structural shear walls disclosed herein, by using the gypsum-based shear face material of the above configuration as a shear face material in wooden structural shear walls, not only can the short-term standard shear strength (P0) and wall factor be effectively increased, but by reducing the surface density of the gypsum-based shear face material, the weight of the face material can be reduced, improving the construction of the shear wall, etc.

[0051] Furthermore, the method for increasing the wall factor of a wooden shear wall according to the present disclosure ensures the minimum physical properties (nail lateral resistance = 500 N or more) required for a gypsum-based shear wall, while reducing the surface density. This improves the toughness and deformation compliance of the gypsum-based shear wall, increases the initial stiffness (K), and reduces the yield displacement (δv), thereby increasing the ultimate strength (corrected value) (Pu'), and thus the short-term standard shear strength (P0) and wall factor. This method for increasing the wall factor of a shear wall using the low-density gypsum-based shear wall can be increased without relying on reinforcement or stiffening with additional reinforcing or stiffening materials, without relying on an increase in the specific gravity and / or thickness of the gypsum-based shear wall, and without significantly relying on an increase in the ultimate displacement (δu). [Brief explanation of the drawings]

[0052] [Figure 1] This is a diagram illustrating the envelope of the load-deformation curve (shown by the solid line) obtained by an in-plane shear test of a wooden structural shear wall, and the dot-dash line shows a linear graph in which the envelope of the load-deformation curve is converted into the load-deformation characteristic of a perfectly elasto-plastic model. [Figure 2] 1 is a front view schematically showing an embodiment of a load-bearing wall of a wooden structure building to which the present disclosure is applied. [Figure 3]3A to 3C are a front view, a cross-sectional view, and a side view showing the configuration of a shear wall specimen used in an in-plane shear test of the shear wall structure shown in FIG. 2. [Figure 4] 1 is a table showing the physical properties and formulations of gypsum-based load-bearing surface materials according to examples and comparative examples of the present disclosure. [Figure 5] FIG. 1 is a diagram showing the results of an in-plane shear test of a bearing wall structure in which gypsum-based bearing surface materials according to Examples 1 to 4 and the Comparative Example are fixed to a wooden framework, as load-deformation angle characteristics of a perfectly elastic-plastic model. [Figure 6] FIG. 1 is a partial front view of a testing device conceptually illustrating a compressive strength measuring method for measuring compressive strength. DETAILED DESCRIPTION OF THE INVENTION

[0053] Hereinafter, the configuration of a wooden structural shear wall according to a preferred embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0054] FIG. 2 is a front view schematically showing the configuration of a wooden structural load-bearing wall (bearing wall) of a wooden structural building according to an embodiment of the present disclosure.

[0055] The bearing wall 1 shown in FIG. 2 is a wooden frame construction bearing wall constructed by fixing a bearing face panel 10 to a wooden frame on a continuous footing F of a reinforced concrete (RC) structure. The bearing face panel 10 has dimensions of 9.5 mm thick, 910 mm wide, and about 2800 to 3030 mm (for example, about 2900 mm) high, and has a strength of 6.5 to 8.9 kg / m 2 areal density within the range of (e.g., areal density 7.5 kg / m 2 ). The areal density (also called areal weight) is the mass (weight) per unit area of ​​the wall surface when viewed from the front. The load-bearing surface material 10 is a gypsum-based surface material composed of a flat gypsum core (gypsum core material) mixed with a predetermined amount of inorganic fiber (glass fiber) and organic strength-enhancing material (starch), and gypsum board base paper (paper component) covering both sides of the gypsum core.

[0056] The bearing wall 1 has a base 2 fixed to the top surface of a continuous footing F with anchor bolts B. The bearing wall 1 is generally composed of this base 2, columns 3, partition studs 4, and inter-joint columns 4' arranged vertically at predetermined intervals on the base 2, horizontal cross members (beams, girths, eaves beams, gable beams) 5 supported on the upper ends (or middle parts) of the columns 3, and the above-mentioned bearing surface material 10. The base 2, columns 3, partition studs 4, inter-joint columns 4', and cross members 5 that make up the framework are made of wood (square timber) with the cross section used in ordinary wooden buildings.

[0057] The bearing surface panel 10 is fixed to the sill 2, columns 3, studs 4, inter-joint columns 4', and cross members 5 by nails 20. The nails 20 are, for example, galvanized iron round nails (NZ nails: JIS A 5508). In this example, NZ50 nails (length 50 mm, head diameter approximately 6.6 mm, shank diameter approximately 2.75 mm) are used as the nails 20. The nails 20 are arranged at intervals S1 in the four outer peripheral zones of the bearing surface panel 10, and at intervals S2 in the central zone of the bearing surface panel 10 extending in the vertical direction. Preferably, the interval S1 is set to a dimension within a range of 50 mm to 200 mm (e.g., 75 mm), and the interval S2 is set to a dimension within a range of 50 mm to 300 mm (e.g., 150 mm).

[0058] The gypsum core (core material) of the bearing surface material 10 contains a predetermined amount of inorganic fibers and an organic strength-enhancing material and has a nail side resistance of 500 N or more. The amount of inorganic fibers is 0.3 to 5 parts by weight, preferably 2 to 4 parts by weight, per 100 parts by weight of calcined gypsum. Examples of inorganic fibers to be added include glass fiber and carbon fiber. When glass fiber is used, glass fiber having a diameter of 5 to 25 μm and a length of 2 to 25 mm can be preferably used. The amount of organic strength-enhancing material to be added is 0.3 to 15 parts by weight, preferably 1 to 13 parts by weight, per 100 parts by weight of calcined gypsum. Examples of organic strength-enhancing materials to be added include starch, polyvinyl acetate, polyvinyl alcohol, and polyacrylic. Both unmodified and modified starches can be used as the starch. Examples of modified starches include starches that have been subjected to physical, chemical, or enzymatic treatment. Pregelatinized starch can be suitably used as the physically treated starch, and oxidized starch, phosphated starch, urea phosphated starch, hydroxypropylated phosphate cross-linked starch, hydroxyethylated starch, hydroxypropylated starch, cationized starch, and acetylated starch can be suitably used as the chemically treated starch.

[0059] The composition and structure of the bearing surface material 10 are similar to those of the "structural gypsum board" specified in JIS A 6901. However, the surface density of the bearing surface material 10 is 6.5 to 8.9 kg / m 2 A value within the range (e.g., 7.5 kg / m 2 ) Therefore, the bearing surface material 10 has a strength of 9.4 kg / m as mentioned above. 2 This is fundamentally different from the "structural gypsum board" specified in JIS A 6901, which requires an areal density of 9.4 kg / m or more. Also, "reinforced gypsum board" specified in JIS A 6901 is known, but "reinforced gypsum board" also has an areal density of 9.4 kg / m. 2Since the load-bearing surface material 10 requires an area density of 500 N or more, it is fundamentally different from "reinforced gypsum board." The load-bearing surface material 10 also differs from other "gypsum boards" in that it has a main or core material that is a blend of inorganic fiber and organic strength-enhancing material to provide a nail side resistance of 500 N or more. In other words, the load-bearing surface material 10 does not fall under any of the "gypsum boards" specified in the current JIS A 6901. In this sense, the load-bearing surface material 10 will be specified or expressed as a "gypsum-based load-bearing surface material" in this specification.

[0060] Generally, gypsum-based load-bearing surface materials (including "gypsum board," "reinforced gypsum board," and "structural gypsum board"), which are formed by covering the front and back surfaces of a plate-shaped main material or core material made of a hardened gypsum body with paper members, are manufactured using a general-purpose gypsum board manufacturing apparatus. As described in International Publication WO 2019 / 058936, for example, the gypsum board manufacturing apparatus has a mixer that prepares a gypsum slurry by mixing raw materials such as calcined gypsum, adhesive aid, hardening accelerator, and foam (or foaming agent) with mixing water required to form a slurry of the calcined gypsum. The gypsum slurry is poured and spread onto gypsum board base paper (bottom paper) on a conveyor belt of the gypsum board manufacturing apparatus, and gypsum board base paper (top paper) is layered on the gypsum slurry. The strip-shaped continuous laminate with a three-layer structure thus formed is processed by various devices constituting a gypsum board manufacturing apparatus, such as a rough cutting device, a forced drying device, and a cutting device, to form a gypsum product of a predetermined size, i.e., a gypsum-based facing material in which both sides of a hardened gypsum slurry body (i.e., a gypsum core) are covered with gypsum board base paper. The specific gravity of the gypsum-based facing material is adjusted mainly by the amount of bubbles in the gypsum slurry.

[0061] Regarding wooden structural shear walls that use structural gypsum board, reinforced gypsum board, and (ordinary) gypsum board as the load-bearing surface material as specified in JIS A 6901, examples of wall coefficients for shear walls made of large wooden frame structures as specified in the aforementioned Ministry of Construction Notification No. 1100 are as follows: Structural gypsum board (Type A) 1.7 Structural gypsum board (Type B) 1.2 Reinforced gypsum board 0.9 (Normal) Gypsum board 0.9

[0062] In addition, examples of wall coefficients for frame wall construction shear walls (shear walls with a vertical frame spacing of more than 50 cm) specified in the aforementioned Ministry of Land, Infrastructure, Transport and Tourism Notification No. 1541 are as follows: Structural gypsum board (Type A) 1.7 Structural gypsum board (Type B) 1.5 Reinforced gypsum board 1.3 (Normal) Gypsum board 1.0

[0063] As such, the wall factor values ​​specified in the notices of the Ministry of Construction or the Ministry of Land, Infrastructure, Transport and Tourism are generally applicable without the need for individual performance tests. However, structural gypsum board, reinforced gypsum board, and (ordinary) gypsum board that are recognized as effective load-bearing surface materials are limited to those with a thickness of 12 mm or more. Therefore, when using new surface materials or gypsum-based surface materials with a thickness of less than 12 mm as load-bearing surface materials, or when using a different wall factor, it is necessary to conduct the aforementioned performance tests to determine the wall factor value.

[0064] As mentioned above, the structural gypsum board and reinforced gypsum board specified in JIS A 6901 have an areal density of 9.4 kg / m 2 The surface density and specific gravity must be 0.75 or more. This is considered to be an important condition for increasing the maximum load that the surface material can withstand and for ensuring high short-term allowable shear strength (and therefore high wall ratio) for wooden structural shear walls. In particular, for structural gypsum board, which must exhibit higher nail lateral resistance than reinforced gypsum board, it has been thought that such surface density and specific gravity cannot be reduced. That is, a surface density of 9.4 kg / m 2As mentioned above, ensuring a specific gravity of 0.75 or higher was considered essential for further increasing the wall strength of shear wall specimens (wooden shear walls) obtained in the aforementioned in-plane shear tests. However, recent experiments by the present inventors and others have shown that for gypsum-based facings that are given properties (nail lateral resistance) comparable to those of structural gypsum boards by adding inorganic fibers or organic strength enhancers, reducing the thickness of the facing or adjusting the foam content to reduce the specific gravity of the gypsum core, thereby reducing the areal density, reveals the inherent toughness or deformation compliance of the facing, thereby effectively utilizing the ultimate strength of the bearing wall and increasing its ductility, thereby further improving the short-term allowable shear strength of the bearing wall. This point is as described in Patent Document 3.

[0065] Furthermore, recent experiments by the inventors have revealed that increasing the compressive strength of gypsum-based shear panels increases the initial rigidity of the shear wall, thereby reducing the yield point displacement without significantly reducing the ultimate displacement of the shear wall, and as a result, the plasticity factor of the shear wall can be increased relatively significantly.

[0066] As mentioned above, the compressive strength and nail lateral resistance of gypsum-based bearing surface materials can be increased by feeding an organic strength improver such as starch, polyvinyl acetate, polyvinyl alcohol, or polyacrylic together with inorganic fibers to a gypsum slurry kneading mixer to incorporate appropriate amounts of the organic strength improver and inorganic fibers into the gypsum slurry. The blending of the organic strength improver into the gypsum slurry is carried out at a relatively low areal density (6.5 to 8.9 kg / m). 2 While ensuring the surface density within the range of 6.5N / mm 2 It is an effective means of imparting a compressive strength of 1000 N or more to gypsum-based load-bearing surface materials, and also of working with inorganic fibers to impart the desired nail lateral resistance (nail lateral resistance of 500 N or more) to gypsum-based load-bearing surface materials.In addition, considering that the blending of organic strength-enhancing materials does not significantly affect the overall quality of gypsum-based load-bearing surface materials, it is a simple and yet realistically or practically effective means.

[0067] Figure 3 is a front view, a cross-sectional view, and a side view showing the configuration of the shear wall specimen used in the in-plane shear test on the shear wall structure shown in Figure 2. Figures 4 and 5 are a table and a diagram showing the test results of the in-plane shear test. In Figure 3, the same reference numerals are used for the components or components of the shear wall specimen that correspond to or correspond to the components or components shown in Figure 2.

[0068] In accordance with the specimen specifications described in the "Wooden Shear Walls and Their Magnification Factors Performance Testing and Evaluation Procedure Manual," the inventors fabricated a shear wall specimen (hereinafter simply referred to as "specimen") with a wall width of 1,820 mm and a height of 2,730 mm having the shear wall structure shown in Figure 3 as a specimen for the shear wall structure shown in Figure 2, and conducted an in-plane shear test using an unloaded caustic testing device.

[0069] The specimen shown in Figure 3 has a wooden frame structure consisting of a 105 x 105 mm cross-section cedar sill 2 and column 3, and a 180 x 105 mm cross-section Douglas fir cross member 5 supported by the column 3. A 45 x 105 mm cross-section cedar inter-column 4' is erected in the center between the columns 3, and a 27 x 105 mm cross-section cedar stud 4 is erected between the column 3 and the inter-column 4'. Cedar or Douglas fir ties 5' are installed between the column 3 and the stud 4, and between the stud 4 and the inter-column 4'. A pull-out metal fitting 40 is installed as a test fixture at the joint between the sill 2 and column 3, and at the joint between the cross member 5 and the column 3. The base 2, columns 3, joint columns 4', partitions 4, cross members 5 and cross ties 5' constitute the axial members of the load-bearing wall structure, and these members (axial members) form a rectangular framework.

[0070] In the specimen shown in Figure 3, the vertical distance h1 between the base 2 and the cross member 5, the height h2 of the junction 5', and the relative height h3 of the cross member 5 relative to the junction 5' were set to h1 = 2625 mm, h2 = 1790 mm, and h3 = 835 mm, respectively. The distance w1 between the column 3 and the joint column 4' (column center distance) was set to w1 = 910 mm, and the wall length L was set to 1.82 m. The panel 10 was divided into upper and lower sections by the junction 5'. The lower panel 10a had dimensions of 910 mm wide and 1820 mm high, and the upper panel 10b had dimensions of 910 mm wide and 865 mm high. The overlap dimensions h4 and h5 of the panels 10a and 10b were set to 30 mm.

[0071] In the test specimen shown in Figure 3, the nails 20 used to fasten the face panels 10a, 10b to the sill 2, columns 3, joint columns 4', cross members 5, and truss 5' were arranged at equal intervals (interval S1 = 75 mm) around the entire periphery of the edge zones of the face panels 10a, 10b. The nails 20 used to fasten the face panels 10a, 10b to the studs 4 were arranged at equal intervals (interval S2 = 150 mm) in the vertical center zones of the face panels 10a, 10b. NZ50 nails (length 50 mm, head diameter approximately 6.6 mm, shank diameter approximately 2.75 mm) were used as the nails 20.

[0072] The inventors fabricated gypsum-based bearing surface materials according to Examples 1 to 4 and Comparative Example shown in the table of Fig. 4 as specimens, and conducted in-plane shear tests using an unloaded caustic testing device. As described above, the gypsum-based bearing surface materials according to Examples 1 to 4 and Comparative Example are surface materials composed of a flat gypsum core (gypsum core material) mixed with a predetermined amount of inorganic fiber (glass fiber) and organic strength improver (starch), and gypsum board base paper (paper member) covering both sides of the gypsum core, and have a shear strength of about 7.4 to about 8.7 kg / m 2The comparative gypsum-based bearing surface material has a flat gypsum core (gypsum core material) containing a larger amount of inorganic fiber (glass fiber) and organic strength-enhancing material (starch) than conventional gypsum-based bearing surface materials (e.g., the gypsum-based bearing surface material described in Patent Document 4). A test specimen in which the comparative gypsum-based bearing surface material was fixed to a wooden framework was able to increase the ultimate displacement δu of the bearing wall 1 and increase the plasticity factor of the bearing wall 1 compared to conventional gypsum-based bearing surface materials, achieving a relatively high ultimate strength (corrected value) Pu' (7.62 kN). In other words, the comparative gypsum-based bearing surface material is equivalent to the gypsum-based bearing surface material described in Patent Document 3. The blending amounts of inorganic fiber and organic strength-enhancing material shown in Figure 4 are expressed in parts by weight per 100 parts by weight of calcined gypsum.

[0073] In contrast to this, in the present disclosure, in order to further increase the ultimate strength (corrected value) Pu', as described above, a configuration is further adopted in which the compressive strength possessed by the face material is increased to increase the initial stiffness K of the shear wall 1, and the yield point displacement δu is reduced to increase the plasticity factor μ. That is, the specimens of the shear wall 1 formed by fixing the gypsum-based shear wall surfaces of Examples 1 to 4 according to the present disclosure to a wooden framework (hereinafter referred to as "the specimens of Examples 1 to 4") have a compressive strength (6.0 kg / m) of the gypsum-based shear wall surface material of the comparative example. 2 ) and initial stiffness K(1.94kN / 10 -3 rad) has a higher compressive strength (6.5-11.1 kg / m 2 ) and initial stiffness K (2.04~2.91kN / 10 -3 As a result, the yield point displacement δu (6.04 × 10 -3 rad~6.80×10 -3 rad) is the yield point displacement δu (7.26 × 10 -3 rad), the plasticity modulus μ (4.32 to 5.78) of the specimens of Examples 1 to 4 is significantly increased compared to the plasticity modulus μ (4.15) of the specimen of the comparative example.

[0074] 4, the ultimate strength (corrected value) Pu' and short-term allowable shear strength Pa of the specimens of Examples 1 to 4 were Pu' = 7.8 to 11.9 kN and Pa = 5.85 to 8.92, which are significantly higher than the ultimate strength (corrected value) (= 7.62 kN) and short-term allowable shear strength Pa (= 5.72 kN) of the specimen of the comparative example. Also, assuming a reduction coefficient α = 0.75 and a variation coefficient β = 1.0, the wall factor of the specimens of Examples 1 to 4 was 1.64 to 2.50, which is significantly higher than the wall factor (1.60) of the specimen of the comparative example.

[0075] The test results for each specimen in Examples 1 to 4 and Comparative Example were approximately the deformation angle = 20 × 10 -3 Before and after reaching rad, after reaching the maximum load (maximum strength) Pmax (Fig. 1), the structure does not break immediately, but instead reaches the deformation angle in the 0.8Pmax load drop region, i.e., the ultimate displacements δu1 to δu5 (Fig. 5), due to the subsequent repeated loading. The ultimate displacements δu1 to δu5 are approximately 30×10 -3 The deformation angle was about 1.5 rad. This means that, after the maximum load (maximum strength) Pmax was reached, each test specimen in Examples 1 to 4 and Comparative Example continued to undergo plastic deformation due to subsequent repeated loading until a deformation angle of approximately 1.5 times the deformation angle at the maximum load Pmax was reached. As mentioned above, this continuity of plastic deformation is thought to be due to the fact that the surface density was reduced while maintaining the minimum physical properties required for a gypsum-based load-bearing surface material (nail lateral resistance: 500 N or more), thereby making the toughness or deformation compliance inherent in the gypsum board itself apparent.

[0076] 5 shows the test results of each specimen of Examples 1 to 4 and Comparative Example as a linear graph of the load-deformation angle characteristics of the completely elastic-plastic model. -3The linear function line Y=KX in the linear elastic region set at 1000 kJ / rad is shown by a two-dot chain line as the reference line for the initial stiffness K in this disclosure. Furthermore, Fig. 5 shows the linear function lines Y=K1X to Y=K5X in the linear elastic region, the ultimate strengths Pu1 to Pu5, and the yield points σs1 to σs5 for each of the test specimens of Examples 1 to 4 and the comparative example. As shown in Fig. 4, the initial stiffness of each of the test specimens of Examples 1 to 4 was K4=2.04 kN / 10 at its minimum value. -3 rad, and at the maximum value K3=2.91kN / 10 -3 On the other hand, the initial stiffness of the comparative specimen is K2 = 1.94 kN / 10 -3 rad. The initial stiffness K appears in Figure 5 as the gradient of the linear function line of Y = KX. -3 In the specimens of Examples 1 to 4 showing values ​​of rad or more, the linear function lines of Y=K1-4X correspond to the initial stiffness K=2.0 kN / 10 -3 The initial stiffness K5 is 2.0kN / 10 -3 In the comparative example showing values ​​less than rad, the linear function line of Y = K5X is the initial stiffness K = 2.0 kN / 10 -3 5 as a straight line with a gentler gradient than the reference line of rad. That is, in each of the specimens of Examples 1 to 4 in which the compressive strength was increased, the initial stiffness K1-4 was 2.0 kN / 10 -3 rad or more, resulting in relatively small yield point displacements δv1 to δv4, which, combined with the relatively large ultimate displacements δu1 to δu4 and ultimate strengths Pu1 to Pu4, result in relatively large ultimate strengths (corrected values) Pu', short-term allowable shear strength Pa, and wall factor as shown in Figure 4, compared to the comparative example.

[0077] FIG. 6 shows a schematic diagram of a method for measuring the compressive strength of a gypsum-based bearing surface material.

[0078] The compressive strength of the gypsum-based bearing surface materials was measured by cutting the gypsum-based bearing surface materials of each Example and Comparative Example into 4 cm × 4 cm flat plates, as shown in Figure 6. For each Example and Comparative Example, multiple test pieces 101 were fabricated. Four identical test pieces 101 were stacked together without bonding to form a test piece stack 100, which was then inserted between upper and lower loading plates 102 and 103 of a measuring device. A vertical compressive load Fv (and reaction force Rv) was applied to the test piece stack 100 using upper and lower loading rods 104, destroying the main or core material (i.e., the gypsum core portion of the test piece 101) made of hardened gypsum. The compressive load Fv at the time of destruction was measured. A precision universal testing machine (Shimadzu Corporation, "Autograph," Model: AG-10NKI) was used as the measuring device. The inventors measured the compressive load Fv at the time when any of the test pieces 101 constituting the test piece stack 100 was compressed and fractured, and calculated the measured value based on the area (16 cm 2 ) was determined as the compressive strength of each gypsum-based load-bearing surface material.

[0079] The compressive strength of the gypsum-based bearing surface materials of each Example and Comparative Example thus identified is shown in Figure 4. As shown in Figure 4, the initial stiffness K of the gypsum-based bearing surface materials of each Example and Comparative Example varies in response to an increase or decrease in compressive strength, and the value of the initial stiffness K can be increased by increasing the compressive strength. Also, as shown in Figure 4, the plasticity factor μ can be varied by increasing or decreasing the initial stiffness K, and the values ​​of the ultimate strength (corrected value) Pu' and short-term allowable shear strength Pa can be changed. According to the various physical properties of Examples 1 to 4 of the present disclosure, the compressive strength of the gypsum-based bearing surface material can be increased to 6.5 N / mm 2 By increasing the value above, an ultimate strength (corrected value) Pu' of 7.8 kN or more can be obtained, as shown in Figure 4.

[0080] As explained at the beginning of this document, the ultimate strength (corrected value) Pu' is the ultimate strength Pu corrected based on the ductility factor μ. The short-term allowable shear strength Pa is the ultimate strength (corrected value) Pu' multiplied by a specified reduction factor α and a specified dispersion factor β. The wall factor is the short-term allowable shear strength Pa divided by a specified reference strength value (L × 1.96). Therefore, the wall factor and short-term allowable shear strength Pa are proportional to the ultimate strength Pu and increase with an increase in the ductility factor μ. The ductility factor μ is proportional to the ultimate displacement δu and inversely proportional to the yield point displacement δv. Therefore, the wall factor and short-term allowable shear strength Pa can be increased by increasing the ultimate displacement δu or decreasing the yield point displacement δv.

[0081] As shown in FIG. 4, the initial stiffness K of each specimen in Examples 1 to 4 was 2.0 kN / 10 -3 rad, and the initial stiffness K of the specimen for the comparative example is 2.0 kN / 10 -3 rad, and the yield point displacements Δv1 to Δv4 of the specimens of Examples 1 to 4 are significantly smaller than the yield point displacement Δv5 of the specimen of the comparative example.

[0082] As shown in Fig. 4, the wall factor and short-term allowable shear strength Pa obtained by the specimens of Examples 1 to 4 are significantly larger than the wall factor and short-term allowable shear strength Pa obtained by the specimens of the comparative example. This is thought to be the result of the difference in yield point displacement δv (and therefore the difference in plasticity factor μ) making a relatively large contribution to the increase in the wall factor and short-term allowable shear strength Pa.

[0083] As explained above, in the bearing wall 1 having the above-described configuration, the bearing surface material 10 is composed of a main material or core material made of a plate-shaped gypsum hardened body blended with inorganic fiber and an organic strength-improving material so as to exhibit a nail side resistance of 500 N or more, and a paper member covering at least the front and back surfaces of the main material or core material, and the surface density of the bearing surface material 10, specified as the mass per unit area of ​​the wall surface, is 6.5 to 8.9 kg / m 2 As a result, the ultimate displacement δu of the shear wall 1 is set to a value within the range of, for example, 28.89 × 10 -3 ~34.98×10-3 rad, and thus, the ultimate displacement δu of a bearing wall using a conventional gypsum-based bearing surface material (for example, the gypsum-based bearing surface material described in Patent Document 4) is 20 × 10 -3 In contrast to the value of the comparative specimen (δu=30.10×10 -3 rad), the ultimate displacement δu of the bearing wall 1 increases significantly. Moreover, the yield point displacements δv1 to δv4 of the bearing walls 1 according to Examples 1 to 4 are 6.04×10 -3 ~6.80×10 -3 rad, and the yield point displacement δv5 of the shear wall according to the comparative example = 7.26 × 10 -3 rad, which is significantly lower than that of the comparative example. As a result, the bearing face panels 10 of Examples 1 to 4 not only increase the ultimate displacements δu1 to δu4 of the bearing wall 1 to increase the plasticity factor μ, but also increase the plasticity factor μ by reducing the yield point displacements δv1 to δv4 of the bearing wall 1. Therefore, even if the ultimate strengths Pu and ultimate displacements δu1 to δu4 of Examples 1 to 4 are equivalent to those of the comparative example, the reduction in the yield point displacements δu1 to δu4 increases the plasticity factor μ, and the wall magnification factor and short-term allowable shear strength Pa can be increased.

[0084] The above describes in detail preferred embodiments and examples of the present disclosure, but it goes without saying that the present disclosure is not limited to the above embodiments and examples, and various modifications and changes are possible within the scope of the present disclosure described in the claims.

[0085] For example, although the above embodiments and examples relate to a bearing wall at the first floor level of a wooden building, the present disclosure can be similarly applied to a bearing wall at the second or third floor level. In the case of a bearing wall at the second or third floor level, the lower end of the bearing face material is fastened to a cross member or the like at the second or third floor level.

[0086] Furthermore, while the above embodiments and examples relate to a wooden frame construction and large-wall construction load-bearing wall structure, the present disclosure may also be applied to a wooden frame construction and large-wall construction load-bearing wall structure. As a modified example, the present disclosure may also be applied to a wooden frame construction and large-wall construction load-bearing wall structure, in which case the load-bearing face material is fastened to vertical frames, lower frames, upper frames, etc. instead of the foundation, columns, and cross members.

[0087] Furthermore, while the specimen shown in Figure 3 is constructed by dividing the gypsum board into upper and lower halves and arranging a tether at the midpoint in the height direction, it is also possible to conduct in-plane shear tests using gypsum boards with a height dimension substantially equal to the total height of the wooden framework. In the latter case, it is believed that the short-term design shear strength can be further increased.

[0088] Furthermore, in the above embodiments and examples, the load-bearing surface materials are fastened to the wooden framework such as pillars and cross members by nails, but the load-bearing surface materials may also be fastened to the wooden framework by other types of fasteners such as screws. [Industrial Applicability]

[0089] This disclosure applies to gypsum-based shear panels for wooden buildings. In particular, this disclosure applies to gypsum-based shear panels whose main or core material is a plate-shaped gypsum hardened body containing inorganic fibers and organic strength-enhancing materials to provide a nail lateral resistance of 500 N or more. This disclosure also applies to a method for increasing the wall strength factor of a wooden shear wall using such gypsum-based shear panels. This disclosure also applies to a shear wall structure and a shear wall construction method for a wooden building, in which such gypsum-based shear panels are fastened to a wooden wall substrate for a wooden frame construction method or a wooden frame wall construction method, and the shear wall is structurally integrally held by the wooden wall substrate. This disclosure allows the wall strength factor of a wooden shear wall to be increased without additional reinforcement or stiffening materials, without increasing the specific gravity and / or thickness of the gypsum-based shear panel, and without further increasing the ultimate displacement (δu), and therefore has significant practical value and effectiveness.

[0090] This international application claims priority to Japanese Patent Application No. 2021-163783, filed on October 5, 2021, the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0091] 1 Load-bearing wall (wooden structure load-bearing wall) 2. Foundation 3 Pillars 4 studs 4' Joint Column 5. Horizontal members (beams, girder beams, eaves beams, gable beams) 5' Jumpsuit 10, 10a, 10b Load-bearing surface material (gypsum-based load-bearing surface material) 20 Nails (fasteners)

Claims

1. In a wooden structural shear wall having a structure in which a gypsum-based shear surface material is fastened to a wooden structural wall base of a wooden framework construction method or a wooden frame wall construction method by fasteners, The load-bearing surface material is composed of a main material or core material made of a plate-shaped gypsum hardened body and a paper member covering at least the front and back surfaces of the main material or the core material, The bearing surface material has a thickness of less than 12 mm, and the surface density or surface weight of the bearing surface material, specified as the mass per unit area of ​​the wall surface, is 6.5 to 8.9 kg / m 2 and has a surface density or surface weight within the range of 500N or more as measured by the measurement method specified in JIS A 6901, and has a nail side resistance of at least 6.5N / mm 2 It has a compressive strength of more than the main material or the core material is blended with glass fiber as an inorganic fiber in a range of 3.0 parts by mass or more and 3.5 parts by mass or less, and with starch as an organic strength improving material in a range of 5.0 parts by mass or more and 8.0 parts by mass or less, A wooden structural shear wall characterized by comprising as a component the shear face material capable of obtaining a corrected value (Pu') of the ultimate strength (Pu) of 7.7 kN or more as the corrected value (Pu') of the ultimate strength (Pu) obtained by an in-plane shear test using a shear wall specimen with a wall length of 1.82 m.

2. The wooden structural shear wall according to claim 1, The bearing surface material has an initial stiffness (K) of 2.0 kN / 10 as measured by the in-plane shear test. -3 rad or more, 6.5N / mm 2 A wooden structural shear wall characterized by having the above compressive strength.

3. In the wooden structural shear wall described in claim 2, the physical properties of the shear wall measured by the in-plane shear test are as follows: (1) 2.2 kN / 10 -3 Initial stiffness (K) above rad, (2) 7.2 x 10 -3 Yield displacement (δv) below rad, (3) Plasticity value (μ) of 4.2 or more; (4) 20 x 10 -3 Ultimate displacement (δu) greater than rad, (5) A yield strength (Py) of 7.7 kN or more that is greater than the corrected value (Pu') of the ultimate strength (Pu), and (6) 7.5 N / mm 2 The above compressive strength, A wooden structural shear wall characterized in that at least one of the physical properties constituted by the above is ensured by setting the surface density or surface weight and the nail lateral resistance, and by mixing the inorganic fiber and organic strength-enhancing material.

4. In the wooden structural shear wall described in claim 3, the corrected value (Pu') of the ultimate strength (Pu) is a value of 8.0 kN or more, and the ultimate displacement (δu) is 22 × 10 -3 rad, and / or the yield strength (Py) is 8.0 kN or more.

5. 5. A wooden structural shear wall according to claim 1, wherein the shear face material has a thickness of less than 12 mm and / or a specific gravity of 0.96 or less.

6. In a construction method for wooden structural shear walls, a gypsum-based shear surface material is fixed to the wooden structural wall substrate of a wooden framework construction method or a wooden frame wall construction method, A gypsum-based bearing surface material composed of a main material or core material made of a plate-shaped gypsum hardened body and a paper member covering at least the front and back surfaces of the main material or the core material is fastened to the wooden structural wall base with fasteners, The bearing surface material has a thickness of less than 12 mm and an areal density or surface weight, which is specified as the mass per unit area of ​​the wall surface, of 6.5 to 8.9 kg / m 2 and has a surface density or surface weight within the range of 500N or more as measured by the measurement method specified in JIS A 6901, and has a nail side resistance of at least 6.5N / mm 2 It has a compressive strength of more than the main material or the core material is blended with glass fiber as an inorganic fiber in a range of 3.0 parts by mass or more and 3.5 parts by mass or less, and with starch as an organic strength improving material in a range of 5.0 parts by mass or more and 8.0 parts by mass or less, A construction method for wooden structural shear walls, characterized in that the construction method comprises, as a component, a shear panel that can obtain a corrected value (Pu') of the ultimate strength (Pu) of 7.7 kN or more as the corrected value (Pu') of the ultimate strength (Pu) obtained by an in-plane shear test using a shear wall specimen with a wall length of 1.82 m.

7. The method for constructing a wooden structural shear wall according to claim 6, The bearing surface material has an initial stiffness (K) of 2.0 kN / 10 as measured by the in-plane shear test. -3 rad or more, 6.5N / mm 2 A construction method for wooden structural shear walls, characterized in that the above compressive strength is maintained.

8. In the construction method of a wooden structural shear wall according to claim 7, the physical properties of the shear wall measured by the in-plane shear test are as follows: (1) 2.2 kN / 10 -3 Initial stiffness (K) above rad, (2) 7.2 x 10 -3 Yield displacement (δv) below rad, (3) Plasticity value (μ) of 4.2 or more; (4) 20 x 10 -3 Ultimate displacement (δu) greater than rad, (5) A yield strength (Py) of 7.7 kN or more that is greater than the corrected value (Pu') of the ultimate strength (Pu), and (6) 7.5 N / mm 2 The above compressive strength, A construction method for wooden structural shear walls, characterized in that at least one of the physical properties consisting of the above is ensured by setting the surface density or surface weight and the nail lateral resistance, and by mixing the inorganic fiber and organic strength-enhancing material.

9. In the construction method of a wooden structural shear wall according to claim 8, the corrected value (Pu') of the ultimate strength (Pu) is 8.0 kN or more, and the ultimate displacement (δu) is 22 × 10 -3 rad, and / or the yield strength (Py) is 8.0 kN or more.

10. 10. The construction method for a wooden structural shear wall according to any one of claims 6 to 9, wherein the shear face material has a thickness of less than 12 mm and / or a specific gravity of 0.96 or less.

11. A method for increasing the wall strength of a wooden structural wall by fastening a gypsum-based shear surface material to the wooden structural wall substrate of a wooden framework construction method or a wooden frame wall construction method with fasteners, The load-bearing surface material is composed of a main material or core material made of a plate-shaped gypsum hardened body and a paper member covering at least the front and back surfaces of the main material or the core material, The load-bearing face material has a thickness of less than 12 mm, and the surface density or surface weight of the load-bearing face material, specified as the mass per unit area of ​​the wall surface, is 6.5 to 8.9 kg / m 2 The nail side resistance measured by the measurement method specified in JIS A 6901 is 500N or more and 6.5N / mm 2 The present invention exhibits a compressive strength of at least 100% by mass or more, and the main material or the core material is blended with glass fiber as an inorganic fiber in a range of 3.0 parts by mass to 3.5 parts by mass or less, and with starch as an organic strength improving material in a range of 5.0 parts by mass to 8.0 parts by mass or less, A method for increasing the wall factor of a wooden structural shear wall, characterized in that the wall has as its component a shear panel that can obtain a corrected value (Pu') of the ultimate strength (Pu) of 7.7 kN or more as the corrected value (Pu') of the ultimate strength (Pu) obtained by an in-plane shear test using a shear wall specimen with a wall length of 1.82 m.

12. The method for increasing the wall strength of a wooden structural shear wall according to claim 11, The initial stiffness (K) of the bearing wall measured by the in-plane shear test is 2.0 kN / 10 -3 rad or more, 6.5N / mm 2 A method for increasing the wall strength of a wooden structural shear wall, characterized by imparting the above compressive strength to the shear face material.

13. In the method for increasing the wall coefficient of a wooden structural shear wall according to claim 12, the physical properties of the front shear wall measured by the in-plane shear test are as follows: (1) 2.2 kN / 10 -3 Initial stiffness (K) above rad, (2) 7.2 x 10 -3 Yield displacement (δv) below rad, (3) Plasticity value (μ) of 4.2 or more; (4) 20 x 10 -3 Ultimate displacement (δu) greater than rad, (5) A yield strength (Py) of 7.7 kN or more that is greater than the corrected value (Pu') of the ultimate strength (Pu), and (6) 7.5 N / mm 2 The above compressive strength, A method for increasing the wall strength of a wooden structural wall, characterized in that at least one of the physical properties consisting of the above is ensured by setting the surface density or surface weight and the nail side resistance, and by mixing the inorganic fiber and organic strength improving material.

14. In the method for increasing the wall ratio of a wooden structural shear wall according to claim 13, the corrected value (Pu') of the ultimate strength (Pu) is a value of 8.0 kN or more, and the ultimate displacement (δu) is 22 × 10 -3 rad, and / or the yield strength (Py) is 8.0 kN or more.

15. 15. The method for increasing the wall factor of a wooden structural shear wall according to any one of claims 11 to 14, wherein the shear face material has a thickness of less than 12 mm and / or a specific gravity of 0.96 or less.

16. In a gypsum-based load-bearing surface material that is fastened with fasteners to the wooden structural wall substrate of a wooden framework construction method or a wooden frame wall construction method, It is composed of a main material or core material made of a plate-shaped gypsum hardened body and a paper member covering at least the front and back surfaces of the main material or the core material, The bearing surface material has a thickness of less than 12 mm and an areal density or surface weight, which is specified as the mass per unit area of ​​the wall surface, of 6.5 to 8.9 kg / m 2 and having an areal density or areal weight in the range of The nail side resistance measured by the measurement method specified in JIS A 6901 is 500N or more, and is at least 6.5N / mm 2 It has a compressive strength of The main material or the core material contains glass fiber as an inorganic fiber in a range of 3.0 parts by mass or more and 3.5 parts by mass or less, and starch as an organic strength improving material in a range of 5.0 parts by mass or more and 8.0 parts by mass or less, A gypsum-based shear surface material characterized in that a corrected value (Pu') of the ultimate strength (Pu) of 7.7 kN or more can be obtained as a corrected value (Pu') of the ultimate strength (Pu) obtained by an in-plane shear test using a shear wall specimen with a length of 1.82 m, in which the shear surface material is fastened to a wooden structural wall base with fasteners.

17. The gypsum-based load-bearing surface material according to claim 16, The bearing surface material has an initial stiffness (K) of 2.0 kN / 10 as measured by the in-plane shear test. -3 rad or more, 6.5N / mm 2 A gypsum-based load-bearing surface material characterized by having the above compressive strength.

18. In the gypsum-based bearing surface material according to claim 17, the physical properties of the bearing wall measured by the in-plane shear test are: (1) 2.2 kN / 10 -3 Initial stiffness (K) above rad, (2) 7.2 x 10 -3 Yield displacement (δv) below rad, (3) Plasticity value (μ) of 4.2 or more; (4) 20 x 10 -3 Ultimate displacement (δu) greater than rad, (5) A yield strength (Py) of 7.7 kN or more that is greater than the corrected value (Pu') of the ultimate strength (Pu), and (6) 7.5 N / mm 2 The above compressive strength, A gypsum-based load-bearing surface material characterized in that at least one of the physical properties constituted by the above is ensured by setting the surface density or surface weight and the nail side resistance, and by blending the inorganic fiber and organic strength-enhancing material.

19. In the gypsum-based bearing surface material described in claim 18, the corrected value (Pu') of the ultimate strength (Pu) is a value of 8.0 kN or more, and the ultimate displacement (δu) is 22 × 10 -3 rad, and / or the yield strength (Py) is 8.0 kN or more.

20. 20. A gypsum-based load-bearing surface material according to any one of claims 16 to 19, characterized in that the load-bearing surface material has a plate thickness of less than 12 mm and / or a specific gravity of 0.96 or less.

21. The gypsum-based load-bearing facing material according to any one of claims 16 to 19, characterized in that it has a laminated structure in which the surface or surface layer of the core material is covered with gypsum board base paper.

22. The gypsum-based load-bearing surface material according to any one of claims 16 to 19, characterized in that the main material or core material of the gypsum-based load-bearing surface material contains an organopolysiloxane compound as a load-bearing deterioration inhibitor that prevents load-bearing deterioration.

23. The gypsum-based load-bearing surface material according to any one of claims 16 to 19, characterized in that the gypsum-based load-bearing surface material has a nail side resistance of 980 N or less.

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