Wooden load-bearing wall, method of constructing wooden load-bearing wall, method of increasing co-efficient of effective wall length of wooden load-bearing wall, and gypsum-based load-bearing board

1 . A wooden load-bearing wall having a structure in which a gypsum-based load-bearing board is fastened, by a fastener, to a wooden wall base used in a wooden framework construction method or in a wooden framework wall construction method,

wherein the gypsum-based load-bearing board includes a main material or a core material formed from a board-shaped hardened gypsum; and a paper covering at least front and back surfaces of the main material or the core material,

wherein the gypsum-based load-bearing board has a surface density or a surface weight, specified as a mass per unit area of a wall surface, in a range from 6.5 kg/m 2 to 8.9 kg/m 2 ; a lateral nail resistance of 500 N or more; and a compressive strength of 6.5 N/mm 2 or more,

wherein the main material or the core material contains glass fiber and starch,

wherein an amount of the glass fiber in the gypsum-based load-bearing board is 3.0 to 3.5 parts by weight per 100 parts by weight of calcined gypsum,

wherein an amount of the starch in the gypsum-based load-bearing board is 5.0 to 8.0 parts by weight per 100 parts by weight of calcined gypsum, and

wherein the gypsum-based load-bearing board has a correction value (Pu′) of an ultimate strength (Pu) of 7.7 kN or more, the correction value (Pu′) of the ultimate strength (Pu) being measured by an in-plane shear test using a test piece of the wooden load-bearing wall with a wall length of 1.82 m.

2 . The wooden load-bearing wall according to claim 1 , wherein the gypsum-based load-bearing board has the compressive strength of 6.5 N/mm 2 or more to provide an initial stiffness (K) of the gypsum-based load-bearing board 2.0 kN/10 −3 rad or more as measured by the in-plane shear test.

3 . The wooden load-bearing wall according to claim 2 , wherein

at least one of physical properties of the wooden load-bearing wall measured by the in-plane shear test is provided by a setting of the surface density or the surface weight and of the lateral nail resistance and by a formulation of the inorganic fiber and the organic-based strength enhancer, and

the physical properties include:

(1) the initial stiffness (K) that is 2.2 kN/10 −3 rad or more;

(2) a yield point displacement (δv) that is 7.2×10 −3 rad or less;

(3) a plasticity (μ) that is 4.2 or more;

(4) an ultimate displacement (δu) that is more than 20×10 −3 rad;

(5) a yield strength (Py) that is 7.7 kN or more and larger than the correction value (Pu′) of the ultimate strength (Pu); and

(6) the compressive strength that is 7.5 N/mm 2 or more.

4 . The wooden load-bearing wall according to claim 3 , wherein the wooden load-bearing wall has at least one of the physical properties including: the correction value (Pu′) of the ultimate strength (Pu) is 8.0 kN or more; the ultimate displacement (δu) is more than 22×10 −3 rad; and the yield strength (Py) is 8.0 kN or more.

5 . The wooden load-bearing wall according to claim 1 , wherein the gypsum-based load-bearing board has a board thickness of less than 12 mm, a specific gravity of 0.96 or less, or both.

6 . A method of constructing a wooden load-bearing wall in which a gypsum-based load-bearing board is fixed to a wooden wall base used in a wooden framework construction method or in a wooden framework wall construction method, the method of constructing a wooden load-bearing wall comprising:

fastening a gypsum-based load-bearing board, by a fastener, to a wooden wall base, in which the gypsum-based load-bearing board includes a main material or a core material formed from a board-shaped hardened gypsum; and a paper covering at least front and back surfaces of the main material or the core material,

wherein the gypsum-based load-bearing board has a surface density or a surface weight, specified as a mass per unit area of a wall surface, in a range from 6.5 kg/m 2 to 8.9 kg/m 2 ; a lateral nail resistance of 500 N or more; and a compressive strength of 6.5 N/mm 2 or more,

wherein the main material or the core material contains glass fiber and starch,

wherein an amount of the glass fiber in the gypsum-based load-bearing board is 3.0 to 3.5 parts by weight per 100 parts by weight of calcined gypsum,

wherein an amount of the starch in the gypsum-based load-bearing board is 5.0 to 8.0 parts by weight per 100 parts by weight of calcined gypsum, and

wherein the gypsum-based load-bearing board has a correction value (Pu′) of an ultimate strength (Pu) of 7.7 kN or more, the correction value (Pu′) of the ultimate strength (Pu) being measured by an in-plane shear test using a test piece of the wooden load-bearing wall with a wall length of 1.82 m.

7 . The method of constructing a wooden load-bearing wall according to claim 6 , wherein the gypsum-based load-bearing board has the compressive strength of 6.5 N/mm 2 or more to provide an initial stiffness (K) of the gypsum-based load-bearing board 2.0 kN/10 −3 rad or more as measured by the in-plane shear test.

8 . The method of constructing a wooden load-bearing wall according to claim 7 , wherein

at least one of physical properties of the wooden load-bearing wall measured by the in-plane shear test is provided by a setting of the surface density or the surface weight and of the lateral nail resistance and by a formulation of the inorganic fiber and the organic-based strength enhancer, and

the physical properties include:

(1) the initial stiffness (K) that is 2.2 kN/10 −3 rad or more;

(2) a yield point displacement (δv) that is 7.2×10 −3 rad or less;

(3) a plasticity (μ) that is 4.2 or more;

(4) an ultimate displacement (δu) that is more than 20×10 −3 rad;

(5) a yield strength (Py) that is 7.7 kN or more and larger than the correction value (Pu′) of the ultimate strength (Pu); and

(6) the compressive strength that is 7.5 N/mm 2 or more.

9 . The method of constructing a wooden load-bearing wall according to claim 8 , wherein the wooden load-bearing wall has at least one of the physical properties including: the correction value (Pu′) of the ultimate strength (Pu) is 8.0 kN or more; the ultimate displacement (δu) is more than 22×10 −3 rad; and the yield strength (Py) is 8.0 kN or more.

10 . The method of constructing a wooden load-bearing wall according to claim 6 , wherein the gypsum-based load-bearing board has a board thickness of less than 12 mm, a specific gravity of 0.96 or less, or both.

11 . A method of increasing a co-efficient of effective wall length of a wooden load-bearing wall constructed by fastening a gypsum-based load-bearing board, by a fastener, to a wooden wall base used in a wooden framework construction method or in a wooden framework wall construction method, the method of increasing the co-efficient of effective wall length comprising:

constituting a gypsum-based load-bearing board to include: a main material or a core material formed from a board-shaped hardened gypsum; and a paper covering at least front and back surfaces of the main material or the core material,

wherein the gypsum-based load-bearing board has a surface density or a surface weight, specified as a mass per unit area of a wall surface, in a range from 6.5 kg/m 2 to 8.9 kg/m 2 ; a lateral nail resistance of 500 N or more; and a compressive strength of 6.5 N/mm 2 or more,

wherein the main material or the core material contains glass fiber and starch,

wherein an amount of the glass fiber in the gypsum-based load-bearing board is 3.0 to 3.5 parts by weight per 100 parts by weight of calcined gypsum,

wherein an amount of the starch in the gypsum-based load-bearing board is 5.0 to 8.0 parts by weight per 100 parts by weight of calcined gypsum, and

wherein the gypsum-based load-bearing board has a correction value (Pu′) of an ultimate strength (Pu) of 7.7 kN or more, the correction value (Pu′) of the ultimate strength (Pu) being measured by an in-plane shear test using a test piece of the wooden load-bearing wall with a wall length of 1.82 m.

12 . The method of increasing a co-efficient of effective wall length of a wooden load-bearing wall according to claim 11 , wherein the gypsum-based load-bearing board has the compressive strength of 6.5 N/mm 2 or more to provide an initial stiffness (K) of the gypsum-based load-bearing board 2.0 kN/10 −3 rad or more as measured by the in-plane shear test.

13 . The method of increasing a co-efficient of effective wall length of a wooden load-bearing wall according to claim 12 , wherein

at least one of physical properties of the wooden load-bearing wall measured by the in-plane shear test is provided by a setting of the surface density or the surface weight and of the lateral nail resistance and by a formulation of the inorganic fiber and the organic-based strength enhancer, and

the physical properties include:

(1) the initial stiffness (K) that is 2. 2 kN/10 −3 rad or more;

(2) a yield point displacement (δv) that is 7.2×10 −3 rad or less;

(3) a plasticity (μ) that is 4.2 or more;

(4) an ultimate displacement (δu) that is more than 20×10 −3 rad;

(5) a yield strength (Py) that is 7.7 kN or more and larger than the correction value (Pu′) of the ultimate strength (Pu); and

(6) the compressive strength that is 7.5 N/mm 2 or more.

14 . The method of increasing a co-efficient of effective wall length of a wooden load-bearing wall according to claim 13 , wherein the wooden load-bearing wall has at least one of the physical properties including: the correction value (Pu′) of the ultimate strength (Pu) is 8.0 kN or more; the ultimate displacement (δu) is more than 22×10 −3 rad; and

the yield strength (Py) is 8.0 kN or more.

15 . The method of increasing a co-efficient of effective wall length of a wooden load-bearing wall according to claim 11 , wherein the gypsum-based load-bearing board has a board thickness of less than 12 mm, a specific gravity of 0.96 or less, or both.

16 . A gypsum-based load-bearing board fastened, by a fastener, to a wooden wall base used in a wooden framework construction method or in a wooden framework wall construction method, the gypsum-based load-bearing board comprising:

a main material or a core material formed from a board-shaped hardened gypsum; and

a paper covering at least front and back surfaces of the main material or the core material, wherein the gypsum-based load-bearing board has a surface density or a surface weight, specified as a mass per unit area of a wall surface, in a range from 6.5 kg/m 2 to 8.9 kg/m 2 ; a lateral nail resistance of 500 N or more; and a compressive strength of 6.5 N/mm 2 or more,

wherein the main material or the core material contains glass fiber an starch,

wherein an amount of the glass fiber in the gypsum-based load-bearing board is 3.0 to 3.5 parts by weight per 100 parts by weight of calcined gypsum,

wherein an amount of the starch in the gypsum-based load-bearing board is 5.0 to 8.0 parts by weight per 100 parts by weight of calcined gypsum, and

wherein the gypsum-based load-bearing board has a correction value (Pu′) of an ultimate strength (Pu) of 7.7 kN or more, the correction value (Pu′) of the ultimate strength (Pu) being measured by an in-plane shear test using a test piece of a wooden load-bearing wall that is formed by fastening the gypsum-based load-bearing board to a wooden wall base, the test piece having a wall length of 1.82 m.

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

18 . The gypsum-based load-bearing board according to claim 17 , wherein

at least one of physical properties of the wooden load-bearing wall measured by the in-plane shear test is provided by a setting of the surface density or the surface weight and of the lateral nail resistance and by a formulation of the inorganic fiber and the organic-based strength enhancer, and

the physical properties include:

(1) the initial stiffness (K) that is 2.2 kN/10 −3 rad or more;

(2) a yield point displacement (δv) that is 7.2×10 −3 rad or less;

(3) a plasticity (μ) that is 4.2 or more;

(4) an ultimate displacement (δu) that is more than 20×10 −3 rad;

(5) a yield strength (Py) that is 7.7 kN or more and larger than the correction value (Pu′) of the ultimate strength (Pu); and

(6) the compressive strength that is 7.5 N/mm 2 or more.

19 . The gypsum-based load-bearing board according to claim 18 , wherein the wooden load-bearing wall has at least one of the physical properties including: the correction value (Pu′) of the ultimate strength (Pu) is 8.0 kN or more; the ultimate displacement (δu) is more than 22×10 −3 rad; and the yield strength (Py) is 8.0 kN or more.

20 . The gypsum-based load-bearing board according to claim 16 , wherein the gypsum-based load-bearing board has a board thickness of less than 12 mm, a specific gravity of 0.96 or less, or both.

21 . The gypsum-based load-bearing board according to claim 16 , wherein the gypsum-based load-bearing board has a laminated structure in which a surface or a surface layer of the core material is covered with the paper.

22 . The gypsum-based load-bearing board according to claim 16 , wherein the main material or the core material of the gypsum-based load-bearing board contains an organopolysiloxane compound as a load-bearing strength deterioration inhibitor to prevent deterioration in load-bearing strength.

23 . The gypsum-based load-bearing board according to claim 16 , wherein the gypsum-based load-bearing board has the lateral nail resistance of 980 N or less.