JP2005314964A - Bearing wall and steel house - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive bearing wall excellent in shearing strength and capable of sufficiently absorbing vibrational energy, and a steel house using the bearing wall. <P>SOLUTION: This bearing wall 1 comprises a steel frame body 2 and a structural surface material 3. The surface material 3 is composed of a cement plate which is obtained by dispersing an inorganic material, a silicic acid-containing substance, lightweight aggregate and reinforcing fibers into water so as to turn them into slurry, dewatering the slurry in a sheet-making manner so as to form a single-layer mat, winding the single-layer mat around a making roll, laminating the plurality of single-layer mats so that the laminated mat can be formed, separating the laminated mats from each other, press-forming them, and hardening and curing them. An average length of the reinforcing fibers is in the range of 1-2.5 mm. In terms of strength characteristics of the surface material 3 after repeated load treatment, an inflection point, where an inclination after the application of a second first maximum breaking load is changed, is provided in a medium load area, subject to a load equivalent to 55±20% of a first maximum breaking load, in a load-deflection curve obtained by a bending test. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a load-bearing wall composed of a steel frame formed by framing shaped steel in a rectangular shape, and a structural face member fixed to the steel frame, and a steel house using the same.

2. Description of the Related Art Conventionally, there is a load-bearing wall composed of a steel frame formed by framing shaped steel in a rectangular shape and a structural face material fixed to the steel frame (see Patent Document 1).
That is, the load-bearing wall is made of a thin lightweight steel plate with a frame structure having a wall structure by a normal frame wall construction method (2 × 4 construction method). A wood plywood is used as the structural face material.
Moreover, the steel house was comprised using such a bearing wall.

However, when it is required to increase the strength of the load-bearing wall in a building where the load-bearing wall cannot be sufficiently arranged, the load-bearing wall using the above-mentioned wood plywood is difficult to obtain its seismic characteristics sufficiently. There is.
That is, when an earthquake occurs, the strength of the bearing wall may decrease due to repeated loads. And there is a possibility that it becomes impossible to endure vibration sufficiently. For example, when a load bearing wall is cracked due to repeated loads, the load bearing wall may not be sufficiently prevented from falling off.

  On the other hand, by constructing a load-bearing wall using wood plywood with an increased thickness, the maximum load-bearing capacity of the load-bearing wall increases, but a steel frame or anchor bolt that can sufficiently withstand the load corresponding to this maximum load-bearing capacity In addition, fixtures such as hole-down hardware are required. This is because the strength of the frame body and the fixture that can cope with the maximum proof stress of the structural face material is determined by the Building Standard Law. Therefore, in this case, there is a problem that the cost is increased.

JP 2001-55807 A

  The present invention has been made in view of such conventional problems, and is intended to provide an inexpensive bearing wall that has excellent shear strength and can sufficiently absorb vibration energy, and a steel house using the same. To do.

The first invention is a load-bearing wall comprising a steel frame formed by framing a shaped steel in a rectangular shape, and a structural face material fixed to the steel frame,
The structural face material comprises a cement-based inorganic material, a silicic acid-containing substance, a lightweight aggregate, and reinforcing fibers dispersed in water to form a slurry, the slurry is made into paper and dehydrated to form a single layer mat, and the single layer The mat is wound around a making roll, and a plurality of layers are laminated to a predetermined thickness to form a laminated mat. The laminated mat is separated from the making roll, press-molded to produce a press mat, and the press mat is cured. It consists of a cement board obtained by curing,
The average length of the reinforcing fiber is 1 to 2.5 mm,
In addition, the structural face material has a strength characteristic after the following repeated load treatment, and a medium load in which a load of 55 ± 20% of the following first maximum breaking load is applied in a load-deflection curve obtained by a bending test. The region has an inflection point where the slope changes after the following second maximum breaking load is applied,
The repeated load process is a process performed by applying 50% of the first maximum breaking load at a pressing speed of 100 mm / min 50 to 100 times in the direction in which the structural face material is bent. Yes,
The first maximum breaking load is a maximum load applied when the structural face material before the repeated load treatment is broken in the bending test,
The second maximum breaking load is in the load bearing wall, which is the maximum load applied when the structural face material after the repeated load treatment is broken in the bending test (Claim 1). .

Next, the effects of the present invention will be described.
The structural face material can improve the strength per layer of the single-layer mat because the lightweight aggregate and the reinforcing fiber are mixed in the raw material. In particular, since the average length of the reinforcing fibers is 1 to 2.5 mm, the strength of the single-layer mat can be sufficiently ensured.
The structural face material can be obtained by forming a laminated mat in which single-layer mats are laminated as described above. That is, since the structural face material is formed in a layer shape, it is excellent in shear strength and toughness.

Thus, the structural face material made of the cement board obtained by the raw materials and methods as described above has sufficient shear strength and sufficient toughness.
The bearing wall has sufficient shear strength and toughness because the structural face material excellent in shear strength and toughness is fixed to the steel frame. And since it is excellent in toughness, the said load-bearing wall can bend comparatively largely and can fully absorb the input vibration energy.

  In addition, the structural face material made of the cement board can be adjusted to have a maximum proof stress to a necessary and sufficient size, for example, by appropriately adjusting the number of layers and the thickness of the laminated mat when the laminated mat is formed. That is, it is possible to prevent the maximum proof stress from being excessively increased and to prevent the necessity of extremely increasing the strength of the steel frame, the anchor bolt, the fixture such as the hole-down hardware, or the like. Therefore, an inexpensive bearing wall can be obtained.

  Further, the structural face material has the inflection point in the medium load region in the load-deflection curve obtained by a bending test in terms of strength characteristics after the repeated load treatment. Therefore, when the structural surface material is subjected to a large load after being repeatedly subjected to an earthquake or the like, even if the structural surface material is cracked, it is still strong enough to support the building. You can bend while keeping Thereby, vibration energy can be absorbed.

  As described above, according to the present invention, it is possible to provide an inexpensive bearing wall that has excellent shear strength and can sufficiently absorb vibration energy.

2nd invention is a steel house which has a load-bearing wall which consists of a steel frame formed by framed a shape steel in a rectangular shape, and a structural face material fixed to the steel frame,
The structural face material comprises a cement-based inorganic material, a silicic acid-containing substance, a lightweight aggregate, and reinforcing fibers dispersed in water to form a slurry, the slurry is made into paper and dehydrated to form a single layer mat, and the single layer The mat is wound around a making roll, and a plurality of layers are laminated to a predetermined thickness to form a laminated mat. The laminated mat is separated from the making roll, press-molded to produce a press mat, and the press mat is cured. It consists of a cement board obtained by curing,
The average length of the reinforcing fiber is 1 to 2.5 mm,
In addition, the structural face material has a strength characteristic after the following repeated load treatment, and a medium load in which a load of 55 ± 20% of the following first maximum breaking load is applied in a load-deflection curve obtained by a bending test. The region has an inflection point where the slope changes after the following second maximum breaking load is applied,
The repeated load process is a process performed by applying 50% of the first maximum breaking load at a pressing speed of 100 mm / min 50 to 100 times in the direction in which the structural face material is bent. Yes,
The first maximum breaking load is a maximum load applied when the structural face material before the repeated load treatment is broken in the bending test,
In the steel house, the second maximum breaking load is a maximum load applied when the structural face material after the repeated load treatment is broken in the bending test (Claim 5). .

This steel house has an inexpensive bearing wall that is excellent in shear strength and can sufficiently absorb vibration energy.
Therefore, according to the present invention, it is possible to provide an inexpensive steel house that has excellent shear strength and can sufficiently absorb vibration energy.

In the first invention (Invention 1) or the second invention (Invention 2), the inflection point is a point at which the inclination after the second maximum breaking load is applied is changed, and the load decreases. This is the point at which the rate of increase in the amount of deflection with respect to begins to increase.
Moreover, as said shape steel, the thin plate lightweight shape steel using the thin plate of thickness 0.8-1.6 mm can be used, for example.
Moreover, the said cementitious inorganic material consists of 1 type, or 2 or more types chosen from Portland cement, blast furnace slag cement, fly ash cement, silica cement, alumina cement, white cement etc., for example.

The silicic acid-containing substance is composed of, for example, one or more selected from slag, fly ash, quartz sand, quartzite powder, silica fume, diatomaceous earth, and the like.
The lightweight aggregate is composed of one or more selected from, for example, pearlite, vermiculite, shirasu balloon, crushed waste material of cement board, and the like.

  Examples of the reinforcing fiber include wood pulp (NUKP, NBKP, LUKP, LBKP, etc.), wood flour, wood fiber bundles such as wood fiber bundles, synthetic fiber such as polypropylene fiber, vinylon fiber, aramid fiber, sepiolite, wallast It consists of 1 type, or 2 or more types chosen from mineral reinforcement fibers, such as knight.

  Moreover, when the average length of the reinforcing fiber is less than 1 mm, it may be difficult to obtain sufficient toughness and shear strength of the bearing wall. On the other hand, if the average length exceeds 2.5 mm, the fibers may become entangled when the material is made into a slurry, and a so-called “duck” state may occur.

  In preparing the slurry, in addition to the cement-based inorganic material, silicate-containing substance, lightweight aggregate, reinforcing fiber, for example, hardening accelerators such as calcium formate and aluminum sulfate, paraffin, wax, A waterproofing agent such as a surfactant or a water repellent may be dispersed.

  Moreover, it is preferable that the solid content density | concentration of the said slurry shall be 5-20 mass%. Thereby, the predetermined thickness of the laminated mat can be obtained efficiently. When the concentration is less than 5% by mass, the thickness of the single-layer mat is too thin, and it is necessary to laminate the multilayer until a predetermined thickness is reached, which may reduce the production efficiency. On the other hand, if it exceeds 20% by mass, the thickness of the single-layer mat is too thick, the dehydration efficiency is lowered, and the adhesion at the lamination interface may be lowered.

  Moreover, it is preferable that the said structural surface material is 10-15 mm in thickness and 0.8-1.1 specific gravity, for example. The laminated mat is preferably formed by laminating 5 to 10 single-layer mats.

Further, it is preferable that the structural face material has a larger or equal longest deflection amount in the medium load region in the bending test after the repeated load treatment than before the repeated load treatment. 6).
In this case, even if the structural surface material is cracked, it can be bent while maintaining sufficient strength to support the building, and vibration energy can be absorbed sufficiently.

In addition, the structural face material is such that the work done in the bending test before the load-deflection curve finally passes through the medium load region is greater after the repeated load treatment than before the repeated load treatment. It is preferable that it is large or equivalent (Claims 3 and 7).
In this case, the energy required until the bearing wall cannot obtain sufficient strength to support the building is increased. Therefore, it is possible to obtain a load-bearing wall and a steel house having sufficient strength.

The structural face material preferably has a specific gravity of 0.8 to 1.1, a bending strength of 8 to 18 N / mm ² , and a maximum deflection of 8 to 14 mm (Claims 4 and 8).
In this case, it is possible to obtain a bearing wall and a steel house that are further superior in shear strength and can sufficiently absorb vibration energy.
Here, the bending strength is the maximum stress when the material breaks due to the bending load, and is a value derived from the equation (1) described later.
The maximum deflection amount is a deflection amount of the structural face material when the first maximum breaking load is applied.

If the specific gravity is less than 0.8, there may be a problem with water resistance and frost resistance as the face material. If the specific gravity exceeds 1.1, handling as the face material may be difficult. is there.
If the bending strength is less than 8 N / mm ² , it may be difficult to obtain sufficient shear strength, and it may be difficult to sufficiently absorb vibration energy. On the other hand, if the bending strength exceeds 18 N / mm ² , the maximum proof stress of the load-bearing wall becomes too large, and it is necessary to increase the strength of other members, such as a steel frame body, which increases costs. May lead to
Moreover, when the maximum deflection amount is less than 8 mm, it may be difficult to obtain sufficient toughness. On the other hand, if the maximum deflection exceeds 14 mm, sufficient shear strength may not be obtained.

Example 1
A bearing wall according to an embodiment of the present invention and a steel house using the same will be described with reference to FIGS.
As shown in FIGS. 1 to 3, the load-bearing wall 1 of the present example includes a steel frame body 2 in which a steel frame 21 is framed in a rectangular shape, and a structural surface material 3 fixed to the steel frame body 2. Become.

The structural face material 3 is made of a cement board obtained as follows.
First, a slurry 41 is obtained by dispersing a cement-based inorganic material, a silicic acid-containing substance, a lightweight aggregate, and reinforcing fibers in water. As shown in FIG. 7, the slurry 41 is formed and dehydrated to form a single layer mat. The single-layer mat is wound around a making roll 51, and a plurality of layers are laminated until a predetermined thickness is formed, thereby forming a laminated mat 43. The laminated mat 43 is separated from the making roll 51 and press-molded to produce a press mat, and the press mat is cured and cured.
Thereafter, by performing external processing or the like, as shown in FIG. 8, a structural face material 3 made of a cement board having a layer structure is obtained.

The average length of the reinforcing fibers 31 dispersed in the structural face material 3 is 1 to 2.5 mm.
Moreover, the structural face material 3 has characteristics as shown in a load-deflection curve M1 in FIG. 11 and load-deflection curves M11, M12 in FIG. 12 as strength characteristics after repeated load processing. That is, in the load-deflection curve obtained by a bending test, the slope after the following second maximum breaking load is applied to the middle load region A where a load of 55 ± 20% of the following first maximum breaking load is applied. It has an inflection point B that changes.

The repeated load treatment is performed by applying 50% of the first maximum breaking load at a pressing speed of 100 mm / min 50 to 100 times in the direction in which the structural face material 3 is bent. It is.
The first maximum breaking load is a maximum load applied when the structural face material 3 before the repeated load treatment is broken in the bending test. The second maximum breaking load is the maximum load applied when the structural face material 3 after the repeated load treatment is broken in the bending test.

The bending test is based on JIS A 1408.
That is, in the bending test, first, as shown in FIG. 10, longitudinal ends of a test body (structural face material 3) having a size of 500 mm × 400 mm and a thickness of about 12 mm are supported by a pair of support members 71. The distance (span) between the two support points is 400 mm. Then, the central portion of the structural face material 3 is pressed by the pressing jig 72. The pressing jig 72 is lowered until the structural face material 3 is broken. Thereby, the structural face material 3 is bent. The relationship between the pressing load by the pressing jig 72 at this time and the amount of deflection of the structural face material 3 is measured.
The amount of deflection is obtained by measuring the amount of displacement of the central portion of the structural face material 3 pressed by the pressing jig 72. The lowering speed of the pressing jig 72 is 100 mm / min.
In addition, in the repeated load treatment, in the configuration shown in FIG. 10, as long as the structural face material 3 is not broken, that is, 50% of the first maximum breaking load is pressed at a pressing speed of 100 minutes / mm. The tool 72 is moved 50 to 100 times, with one reciprocating motion up and down once.

Next, the load-deflection curve of the structural face member 3 used for the load bearing wall 1 of this example will be specifically described with reference to FIGS.
The measurement results shown in FIGS. 11 and 12 are the measurement results for the structural face material 3 manufactured under the same conditions but in different lots (first lot and second lot).

A curve M0 in FIG. 11 and a curve M10 in FIG. 12 are load-deflection curves when the bending test is performed without performing the repeated load process.
A curve M1 in FIG. 11 and a curve M11 in FIG. 12 are load-deflection curves when the bending test is performed after the repeated load process is performed 50 times.
A curve M12 in FIG. 12 is a load-deflection curve when the bending test is performed after the repeated load process is performed 100 times.

The first maximum breaking load on the structural face material 3 (FIG. 11) of the first lot is about 1700 N, and the first maximum breaking load on the structural face material 3 (FIG. 12) of the second lot is about 1630 N. Accordingly, the medium load region A in the measurement shown in FIG. 11 is a region where a load of about 600 to 1280 N is applied, and the medium load region A in the measurement shown in FIG. 12 is a region where a load of about 570 to 1220 N is applied. is there.
As shown in FIGS. 11 and 12, the load-deflection curves (M1, M11, M12) of the structural face material 3 after the repeated load treatment are all performed in the middle load region A and the inflection point B. Have

  Moreover, as shown in FIGS. 11 and 12, the structural face material 3 has the above bending test after the repeated load treatment (M1, M11, M12) than before the repeated load treatment (M0, M10). The longest deflection amount in the medium load region A is large or equivalent. The longest deflection amount is the deflection amount at point C in FIGS.

The longest deflection amount before the repeated load treatment (M0) shown in FIG. 11 is about 12.6 mm, and the longest deflection amount after the repeated load treatment (M1) is about 13.3 mm.
Further, the longest deflection amount before the repeated load treatment (M10) shown in FIG. 12 is about 13.0 mm, and the longest deflection amount after the repeated load treatment (M11, M12) is about 13.5 mm and about 15.0 mm, respectively. is there.

In the structural face material 3, the work done in the bending test until the load-deflection curve finally passes through the medium load region is more repeated than before the repeated load treatment (M0, M10). After the load processing (M1, M11, M12) is larger or equivalent.
11 and 12, the work amount is until the load-deflection curve finally passes through the medium load region A (until the point C is reached, that is, until the longest deflection amount is reached). This corresponds to the area of the region formed on the lower side of the load-deflection curve.

The work amount before the repeated load process (M0) shown in FIG. 11 is about 13.8 J, and the work amount after the repeated load process (M1) is about 14.0 J.
Further, the work amount before the repeated load process (M10) shown in FIG. 12 is about 12.9J, and the work amount after the repeated load process (M11, M12) is about 13.3J and about 14.5J.
The structural face material 3 has a specific gravity of 0.8 to 1.1, a bending strength of 8 to 18 N / mm ² , and a maximum deflection amount of 8 to 14 mm.

Here, the bending strength is the maximum stress when the material breaks due to a bending load, and is a value derived from the following equation (1).
(Bending strength) = (3/2) × (first maximum breaking load) × (span) / {(width of specimen) × (thickness of specimen) ² } (1)

In the above formula (1), the span is a distance between two support points in the bending test, and is 400 mm in this example. In this example, the width of the test specimen is 400 mm, and the thickness of the test specimen is 12 mm.
The maximum deflection amount is the deflection amount of the structural face material 3 when the first maximum breaking load is applied.

  Moreover, as the said shape steel 21 used for the said load-bearing wall 1, the thin plate lightweight shape steel using the thin plate about thickness 1.0mm is used. As shown in FIGS. 5 and 6, as the vertical member 211 in the vertical direction in the steel frame 2, C-shaped steel having a substantially C-shaped cross section is used, and as the horizontal member 212 in the left and right direction, a substantially cross-sectional shape is used. Use a shaped channel steel.

Moreover, as shown in FIGS. 4 and 6, two vertical members 211 (C-shaped steel) are fixed to each other on the left and right sides of the steel frame 2 by overlapping the back surfaces thereof with screws 11. A hole-down hardware 23 for fixing the load bearing wall 1 to the foundation is fixed inside the left and right vertical members 211 below.
In addition, a vertical member 211 (C-shaped steel) is disposed at a substantially central portion with respect to the left and right of the steel frame 2.

Further, as shown in FIG. 5, the cross member 212 (grooved steel) is disposed on the upper side and the lower side of the steel frame 2 so that the opening surfaces thereof face each other. The cross member 212 and the vertical member 211 are fixed by screws 11.
As shown in FIG. 1 to FIG. 3, the bearing wall 1 is obtained by fixing the structural face material 3 to one side of the steel frame 2. That is, the structural face material 3 having substantially the same shape as the outer shape of the steel frame body 2 is fixed to the steel frame body 2 using screws 12.

Next, the manufacturing method of the structural face material 3 will be described in detail.
First, 35% by mass of Portland cement as the cement-based inorganic material, 25% by mass of slag and 10% by mass of fly ash as the silicate-containing substance, 10% by mass of pearlite as the lightweight aggregate, the reinforcing fiber 31 (see FIG. 8) and wood pulp 10% by mass and light aggregate 10% by mass reject are mixed.
This raw material mixture is dispersed in water to obtain a slurry 41 having a solid content of about 12% by mass.

The wood pulp is formed by mixing waste paper pulp and virgin pulp at a ratio of 9: 1 to 5: 5.
The waste paper pulp has a fiber length of 0.1 to 2 mm, an average fiber length of 1 mm, and a Canadian standard freeness of 500 csf or less. Waste paper pulp is waste paper recycled pulp, waste paper pulverized material, etc., for example, newspaper waste paper pulverized material, cardboard waste paper recycled pulp, and the like. The Canadian standard freeness is a numerical value obtained by a test for measuring the freeness of the defibrated and beaten pulp. The smaller the numerical value, the better the drainage of the pulp and the finer the pulp.

  The virgin pulp has a fiber length of 1 to 5 mm, an average fiber length of 2.5 mm, and a Canadian standard freeness of 300 to 800 csf. Virgin pulp is newly produced from the tree itself, NUKP (unleaved kraft pulp), NBKP (unbleached kraft pulp), LUKP (unleaved kraft pulp), LBKP (hardwood kraft pulp) Etc.

  The slurry 41 is charged into a raw material box 52 of a flow-on type papermaking machine 5 shown in FIG. The papermaking machine 5 is in contact with the making roll 51, the raw material flow box 56, the suction box 57, and the making roll 51 and circulates while passing under the raw material flow box 56 and the upper surface of the suction box 57. And felt 55.

  The slurry 41 charged into the raw material box 52 is supplied to the raw material flow box 56 and is flowed from the raw material flow box 56 onto the felt 55. The slurry 41 flowing on the felt 55 is dehydrated by suction by the suction box 57. As a result, a single-layer mat made of a thin raw material layer is formed on the felt 55.

  The single-layer mat formed on the felt 55 in this manner is wound around the making roll 51 and stacked to form a stacked mat 43. Then, when the seven layers of the single-layer mat are laminated, they are cut and developed by the cutter 59, and the laminated mat 43 is separated from the making roll 51. Thereafter, the laminated mat 43 is press-molded to form a press mat.

The press mat is cured and cured for 7 to 30 hours under conditions of a temperature of 50 to 80 ° C. and a humidity of 90 to 100% RH.
Then, the structural surface material 3 which consists of the said cement board is obtained by performing an external shape process etc. The structural face material 3 has a thickness of 10 to 15 mm, a specific gravity of 0.8 to 1.1, and a bending strength of 8 to 18 N / mm ² .

  Further, as shown in FIG. 9, the steel house 6 can be constructed by using a plurality of the load-bearing walls 1 and assembling them.

Next, the function and effect of this example will be described.
Since the structural face material 3 is obtained by mixing the light-weight aggregate and the reinforcing fiber 31 into the raw material, the strength per layer of the single-layer mat can be improved. In particular, since the average length of the reinforcing fibers 31 is 1 to 2.5 mm, the strength of the single-layer mat can be sufficiently ensured.
The structural face material 3 can be obtained by forming a laminated mat in which single-layer mats are laminated as described above. That is, since the structural face material 3 is formed in a layer shape, it is excellent in shear strength and toughness.

Thus, the structural face material 3 made of the cement board obtained by the raw materials and methods as described above has sufficient shear strength and sufficient toughness.
The bearing wall 1 has sufficient shear strength and toughness because the structural face material 3 having excellent shear strength and toughness is fixed to the steel frame 2. And since it is excellent in toughness, the said load-bearing wall 1 can bend comparatively largely, and can fully absorb the vibration energy input.

  Moreover, the structural face material 3 made of the cement board can be adjusted to have a maximum proof stress to a necessary and sufficient size by appropriately adjusting the number of laminated layers and the thickness of the laminated mat, for example. That is, it is possible to prevent the maximum proof stress from being excessively increased, and to prevent the necessity of extremely increasing the strength of the steel frame 2, screws 11, 12, anchor bolts, hole down hardware, and other fixtures. it can. Therefore, an inexpensive bearing wall 1 can be obtained.

  Moreover, as shown in FIGS. 11 and 12, the structural face material 3 has the above-described medium load region in the load-deflection curves M1, M11, and M12 obtained by a bending test in the strength characteristics after the repeated load treatment. A has the above inflection point B. Therefore, when the structural face material 3 is subjected to a large load after being repeatedly subjected to an earthquake or the like, even if the structural face material 3 is cracked, it is sufficient to support the building thereafter. It can be bent while maintaining a high strength. Thereby, vibration energy can be absorbed.

  Further, as shown in FIGS. 11 and 12, the structural face material 3 has a medium load of the bending test after the repeated load treatment (M1, M11, M12) than before the repeated load treatment (M0, M10). The longest deflection amount in the region A is large or equivalent. Therefore, even if the structural face material 3 is cracked, it can be bent while maintaining sufficient strength to support the building, and vibration energy can be absorbed sufficiently.

Further, in the structural face material 3, the amount of work performed in the bending test before the load-deflection curve finally passes through the intermediate load region A is more repeated than before the repeated load treatment (M0, M10). After the load processing (M1, M11, M12) is larger or equivalent.
Therefore, the energy required until the bearing wall 1 cannot obtain sufficient strength to support the building is increased. Therefore, the load-bearing wall 1 and the steel house 6 having sufficient strength can be obtained.

The structural face material 3 has a specific gravity of 0.8 to 1.1, a bending strength of 8 to 18 N / mm ² , and a maximum deflection amount of 8 to 14 mm. Therefore, it is possible to obtain the bearing wall 1 and the steel house 6 that are further excellent in shear strength and can sufficiently absorb vibration energy.

Hereinafter, the relationship between the structure of the structural face material 3 and the strength characteristics will be considered.
Since the structural face material 3 has a laminated structure as described above, even if a large load is applied and a crack or the like is once applied, it is possible to prevent the strength from being lowered at a stretch. That is, it is considered that even if the structural face material 3 is cracked, the progress of cracks can be stopped to some extent at the laminated interface.

Further, the laminated interface is deteriorated when the structural face material 3 is repeatedly subjected to a load. On the other hand, since the structural face material 3 is formed by the raw materials and the manufacturing method as described above, it is considered that the delamination is hardly performed, and a half-bonded / half-peeled state is obtained. Even if the structural face material 3 in such a state is subjected to a large load (the second maximum breaking load) and the strength is reduced due to cracks or the like, the layers are in an overlapped state, so that some strength is obtained. You can bend further while keeping
Thereby, after receiving a repeated load, it is considered that the structural face material 3 can bend while maintaining sufficient strength to absorb vibration energy and support the building.

  As described above, according to this example, it is possible to provide an inexpensive bearing wall that has excellent shear strength and can sufficiently absorb vibration energy.

(Example 2)
In this example, as shown in FIG. 13, a so-called Hatchek type papermaking machine 50 is used in manufacturing the structural face material 3.
The papermaking machine 50 includes a making roll 51, a plurality of inlet boxes 54 in which a rotating cylinder 53 is disposed, and a felt 55 that circulates between the making roll 51 and the rotating cylinder 53 while being in contact with the making roll 51. Have.

  The slurry 41 charged into the raw material box 52 of the papermaking machine 50 is supplied to each inlet box 54 and dehydrated on the outer peripheral surface of the rotating cylinder 53 to form a thin raw material layer. This raw material layer is adsorbed by the felt 55 to form a single layer mat. Further, the raw material layers formed on the outer peripheral surfaces of the plurality of rotating cylinders 53 overlap on the felt 55.

The single-layer mat formed on the felt 55 in this manner is wound around the making roll 51 and stacked to form a stacked mat 43. Then, when the seven layers of the single-layer mat are laminated, they are cut and developed by the cutter 59, and the laminated mat 43 is separated from the making roll 51. Thereafter, the laminated mat 43 is press-molded to form a press mat.
Thereafter, the structural face material 3 is manufactured in the same manner as in Example 1.
Others are the same as those in the first embodiment, and the same effects as those in the first embodiment can be obtained in this embodiment.

(Comparative Example 1)
In this example, as shown in FIG. 14, a bending test was performed on a structural face material used for a conventional bearing wall.
Also in this example, the load-deflection curve W0 when the bending test is performed without performing the repetition process shown in Example 1, and the load-deflection amount when the bending test is performed after performing the above-described repetition process. The curve W1 was compared.

The above-mentioned conventional structural face material does not have a laminated structure, and is mixed with a cement-based inorganic material, a silicic acid-containing material, a piece of wood that is a reinforcing fiber, and water, and sprayed onto a template to apply pressure. It has been fastened.
About the test method, it is the same as that of Example 1, and the said repeated load process was performed by 50 repetitions.
Others are the same as in the first embodiment.

As can be seen from FIG. 14, the curve W <b> 1 does not have an inflection point in the medium load region A.
In the middle load region A, the longest deflection amount after the repeated load process (W1) is smaller than that before the repeated load process (W0).
Specifically, as shown in FIG. 14, the longest deflection amount before the repeated load process (W0) is about 10.3 mm, and the longest deflection amount after the repeated load process (W1) is about 9.2 mm.

Further, the structural face material has a work load that is made in the bending test before the load-deflection curve finally passes through the medium load region, after the repeated load treatment than before the repeated load treatment (W0). (W1) is smaller.
Specifically, the work amount before the repeated load process (W0) is about 6.6 J, and the work amount after the repeated load process (W1) is about 6.0 J.

By performing the repeated load treatment, the maximum breaking load is reduced, and the maximum deflection amount that is the deflection amount at that time is also reduced. Specifically, the bending strength is about 11.5 N / mm ² and the maximum deflection is about 7.5 mm.
From these results, it can be seen that the conventional bearing wall may be difficult to obtain sufficient shear strength and absorbability of vibration energy after being repeatedly loaded.

The front view of a load bearing wall in Example 1. FIG. The side view of a load-bearing wall in Example 1. FIG. FIG. 3 is a top view of a load bearing wall according to the first embodiment. The front view of the steel frame in Example 1. FIG. The side view of the steel frame in Example 1. FIG. FIG. 5 is a cross-sectional view taken along line AA in FIG. 4. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of a flow-on papermaking machine in Embodiment 1. Sectional drawing of the structural surface material in Example 1. FIG. The perspective view of a part of steel house in Example 1. FIG. FIG. 3 is an explanatory diagram of a bending test method in Example 1. FIG. 3 is a diagram showing a load-deflection curve for a first lot in Example 1. FIG. 3 is a diagram showing a load-deflection curve for the second lot in Example 1. FIG. 4 is an explanatory diagram of a Hatchek type papermaking machine in Example 2. The diagram showing the load-deflection curve in a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bearing wall 11, 12 Screw 2 Steel frame body 21 Shape steel 3 Structural surface material 31 Reinforcement fiber 5, 50 Papermaking machine 6 Steel house

Claims (8)

It is a load-bearing wall composed of a steel frame body that is formed by rectangularly framing the shape steel, and a structural face material fixed to the steel frame body,
The structural face material comprises a cement-based inorganic material, a silicic acid-containing substance, a lightweight aggregate, and reinforcing fibers dispersed in water to form a slurry, the slurry is made into paper and dehydrated to form a single layer mat, and the single layer The mat is wound around a making roll, and a plurality of layers are laminated to a predetermined thickness to form a laminated mat. The laminated mat is separated from the making roll, press-molded to produce a press mat, and the press mat is cured. It consists of a cement board obtained by curing,
The average length of the reinforcing fiber is 1 to 2.5 mm,
In addition, the structural face material has a strength characteristic after the following repeated load treatment, and a medium load in which a load of 55 ± 20% of the following first maximum breaking load is applied in a load-deflection curve obtained by a bending test. The region has an inflection point where the slope changes after the following second maximum breaking load is applied,
The repeated load process is a process performed by applying 50% of the first maximum breaking load at a pressing speed of 100 mm / min 50 to 100 times in the direction in which the structural face material is bent. Yes,
The first maximum breaking load is a maximum load applied when the structural face material before the repeated load treatment is broken in the bending test,
The load bearing wall, wherein the second maximum breaking load is a maximum load applied when the structural face material after the repeated load treatment is broken in the bending test.   2. The structural face material according to claim 1, wherein the structural face material has a larger or equal longest deflection amount in the middle load region of the bending test after the repeated load treatment than before the repeated load treatment. Bearing wall.   3. The structural surface material according to claim 1, wherein the structural face material has a work amount that is repeated in the bending test before the load-deflection curve finally passes through the medium load region than before the repeated load treatment. Bearing wall characterized by being larger or equivalent after load treatment. 4. The structural face material according to claim 1, wherein the structural surface material has a specific gravity of 0.8 to 1.1, a bending strength of 8 to 18 N / mm ² , and a maximum deflection amount of 8 to 14 mm. Characteristic bearing wall. A steel house having a load-bearing wall composed of a steel frame formed by framing a shaped steel into a rectangular shape and a structural face material fixed to the steel frame,
The structural face material comprises a cement-based inorganic material, a silicic acid-containing substance, a lightweight aggregate, and reinforcing fibers dispersed in water to form a slurry, the slurry is made into paper and dehydrated to form a single layer mat, and the single layer The mat is wound around a making roll, and a plurality of layers are laminated to a predetermined thickness to form a laminated mat. The laminated mat is separated from the making roll, press-molded to produce a press mat, and the press mat is cured. It consists of a cement board obtained by curing,
The average length of the reinforcing fiber is 1 to 2.5 mm,
In addition, the structural face material has a strength characteristic after the following repeated load treatment, and a medium load in which a load of 55 ± 20% of the following first maximum breaking load is applied in a load-deflection curve obtained by a bending test. The region has an inflection point where the slope changes after the following second maximum breaking load is applied,
The repeated load process is a process performed by applying 50% of the first maximum breaking load at a pressing speed of 100 mm / min 50 to 100 times in the direction in which the structural face material is bent. Yes,
The first maximum breaking load is a maximum load applied when the structural face material before the repeated load treatment is broken in the bending test,
The steel house according to claim 2, wherein the second maximum breaking load is a maximum load applied when the structural face material after the repeated load treatment is broken in the bending test.   6. The structural face material according to claim 5, wherein the length of the longest deflection in the intermediate load region of the bending test is greater or equal after the repeated load treatment than before the repeated load treatment. Steel house.   7. The structural surface material according to claim 5, wherein the structural face material has a work amount that is repeated in the bending test until the load-deflection curve finally passes through the medium load region than before the repeated load treatment. Steel house characterized by being larger or equivalent after load treatment. 8. The structural face material according to claim 5, wherein the structural face material has a specific gravity of 0.8 to 1.1, a bending strength of 8 to 18 N / mm ² , and a maximum deflection amount of 8 to 14 mm. A characteristic steel house.

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