JP7643035B2 - Adhesive-type load-bearing structural surface, construction method for adhesive-type load-bearing structural surface, and adhesive specification determination support program - Google Patents

Description

This invention relates to horizontal structural surfaces (including floor and roof structural surfaces) used in wooden houses and the like, and more specifically to adhesive-type load-bearing structural surfaces in which horizontal surface materials are fixed to structural members or framework members using adhesive, as well as to a method of constructing such structural surfaces and a program that assists in determining the adhesive specifications.

The Building Standards Act requires that building confirmation be obtained for wooden buildings of three stories or more, or wooden houses that exceed a specified area (500 ^m2 ) or height (height 13 m, eaves height 9 m), and therefore structural calculations are carried out when designing such wooden buildings. On the other hand, for wooden buildings two stories or less that are used for residential purposes and have an area below a specified level (hereinafter referred to as "general wooden buildings"), structural calculations do not need to be carried out in principle if simplified calculations of wall volume, etc. and specifications are satisfied, and this is often omitted. The Building Standards Act Enforcement Order contains provisions regarding construction specifications (framework necessary for structural strength), and it is common to determine each specification in accordance with these provisions when designing general wooden buildings.

The construction specifications stipulated in the Building Standards Act Enforcement Order present various types of bearing wall structures (frameworks with walls) and also indicate the strength index (so-called wall factor) according to the structural type (type of framework). In other words, the wall factor indicated here is used as a reference when designing the entire building, selecting the type of bearing wall required for each part of each floor.

As mentioned above, the Building Standards Act Enforcement Order prescribes load-bearing walls, but makes no specific provisions regarding "horizontal structural surfaces" such as the structure of the floor (hereafter referred to as the "floor horizontal structural surface") or the structure of the roof (hereafter referred to as the "roof horizontal structural surface"). Of course, for a general wooden building, there is no need to carry out special structural calculations for the horizontal structural surfaces. In other words, in terms of the load-bearing structure of a wooden building, it can be said that load-bearing walls are given more importance than the horizontal structural surfaces.

However, the horizontal structural planes also function as load-bearing structures, and when considering the strength of a wooden building as a whole, it is natural that the strength of the horizontal structural planes cannot be overlooked. The main role of the horizontal structural planes is to transmit horizontal forces, including earthquake loads, to the load-bearing walls. If the rigidity of the horizontal structural planes is low, they may deform or bend significantly, or may be damaged or destroyed before the load-bearing walls do, and in such cases the load-bearing walls cannot perform to their full potential. If the horizontal structural planes transmit horizontal forces appropriately (in other words, in a balanced manner) to the surrounding load-bearing walls, the load-bearing walls will function effectively, and as a result, the wooden building will be able to resist external forces. In other words, the rigidity, strength, and toughness (hereinafter collectively referred to as "strength") of the horizontal structural planes contribute in no small way to the strength of the entire wooden building, and for this reason the horizontal structural planes are also required to have a considerable strength.

Because horizontal structural surfaces affect the strength of wooden buildings, there are times when the strength of horizontal structural surfaces is actively evaluated, even for general wooden buildings. For example, housing manufacturers may emphasize that their wooden buildings are stronger than those of other companies in that they have high strength horizontal structural surfaces in addition to the bearing walls. In such cases, the standard indicator of the strength of the floor horizontal structural surfaces is the "floor factor (here, the roof horizontal structural surface is also referred to as the "floor factor"). The Act on Promotion of Housing Quality Assurance (hereinafter referred to as the "Housing Quality Assurance Act") stipulates earthquake resistance grades (grades 1 to 3) as housing performance indicators, and the floor factor is one of the factors used to determine this earthquake resistance grade. The floor factor is determined in accordance with the Japanese Housing Performance Indication Standards stipulated in the Housing Quality Assurance Act.

The strength of the horizontal structural components (i.e., the floor magnification) is also important for long-lasting quality housing that is eligible for special tax treatment. Specifically, a certain earthquake resistance grade (grade 2 or higher) is required to be certified as a long-lasting quality house, meaning that an appropriate floor magnification is necessary. In addition, when wooden buildings other than detached houses are constructed of wood, such as schools, kindergartens, offices, and public facilities, structural calculations of the horizontal structural components are required depending on the scale and use, and as a result, horizontal structural components with an appropriate floor magnification are sometimes planned. In particular, the greater the distance between the load-bearing walls (i.e., the larger the space you want to make), the higher the magnification of the horizontal structural components is required.

As mentioned above, the floor multiplier is determined in accordance with the Japan Housing Performance Indication Standards. Specifically, several structural types of horizontal structural surfaces are exemplified, and a floor multiplier (existing floor multiplier) is set for each structural type. In addition, although the term "Allowable Stress Design for Wooden Frame Construction Houses (2017 Edition)" does not use the term "floor multiplier," it does indicate the relationship between the specifications of the horizontal structural surface and its strength (allowable shear strength per unit length). The allowable shear strength per unit length shown here can be converted to the floor multiplier by dividing it by a conversion value of 1.96 (kN/m).

The structural types (specifications) of horizontal structural components listed in the Japan Housing Performance Indication Standards and the Allowable Stress Design for Wooden Frame Construction Houses (hereinafter collectively referred to as "Conventional Standards, etc.") are all determined by a combination of the type of surface material, the nail specifications (type and installation interval), the joist specifications (dimensions and installation interval), and the joint specifications between the joists and the beams. Note that nail materials here refer to a general term for fasteners such as commonly used round iron nails (N nails, CN nails), screw nails, and screws. Therefore, when designing horizontal structural components, it was common to select structural types based on these combinations, and it was extremely rare to plan structural types that included other elements (for example, the use of fixing materials other than nails).

In addition, according to conventional standards, the floor ratio also varies depending on the arrangement of the nails, and a format in which nails are installed in three or more rows only on one side of the floor material (so-called "river-shaped" format) has a smaller floor ratio than a format in which nails are installed around the entire circumference of the floor material (so-called "Rectangular" format). For example, in the Japanese Housing Performance Indication Standards, when round iron nails N75 are nailed into structural plywood with a thickness of 24 mm or more at intervals of 150 mm or less, the floor ratio (existing floor ratio) is set to 3.0 for the Rectangular format, while the floor ratio is set to 1.2 for the Rectangular format. Thus, the current situation is that the horizontal structural surface in the Rectangular format cannot achieve a very high floor ratio. On the other hand, the Rectangular format is advantageous in terms of cost as it is easy to design the arrangement of beams and the volume of beams can be reduced, so horizontal structural surfaces with a high floor ratio using the Rectangular format are in demand.

When calculating the floor strength, such as the floor magnification and allowable shear strength, it is common to use an envelope curve. This envelope curve is a widely known graph, as shown in "Allowable Stress Design for Wooden Frame Construction Houses", and is a curve that shows the relationship between the load and deformation angle obtained from an in-plane shear test of a horizontal structural member. Specifically, as shown in the detailed diagram of the test specimen in Figure 13, a force is applied to one side of the upper end of the horizontal structural member in a vertical position until the deformation angle is set in advance in stages (however, the force is repeatedly applied in alternating positive and negative directions), and the curve that connects the results obtained at each loading stage is the envelope curve.

FIG. 14 is a diagram showing the envelope of a horizontal structural surface in which floor materials are fixed to beam materials by nail materials, with the horizontal axis showing the deformation angle (rad) and the vertical axis showing the load. As shown by this envelope, the horizontal structural surface fixed by nail materials increases in load until a certain deformation angle (approximately 60×10 ⁻³ rad in this diagram) occurs. In other words, it can be said that the nail materials resist the load until this certain displacement angle occurs. In general, it is assumed that a wooden building will have a deformation angle of about 1/120 rad in the case of a medium-scale earthquake, and a deformation angle of about 1/30 rad in the case of a large-scale earthquake. Therefore, it can be seen that the nail materials resist the horizontal structural surface showing the envelope of this diagram until a relatively large displacement angle that exceeds a large-scale earthquake occurs.

However, looking at the envelope in this figure, we can see that the initial deformation angle graph rises gradually, meaning that even a relatively small load is enough to cause the deformation angle (1/120 rad) expected in a medium-scale earthquake. In other words, while the nail material effectively resists a relatively large load range, it has a weakness in that it easily deforms in a relatively small load range. The higher the rigidity of the horizontal structural members, the smoother the transmission of force to the walls, and the floor multiplier also tends to be evaluated as high, so resolving this weakness can be seen as a major challenge.

Patent Document 1 discloses an invention in which flooring is fixed to beams with adhesive in addition to nails, so that it does not easily deform in a relatively small load range. The envelope of a horizontal structural surface fixed with adhesive has a large rise in the graph in the elastic range (initial deformation angle), and is characterized by not easily deforming in a relatively small load range. On the other hand, the envelope of a horizontal structural surface fixed with nails has the characteristic of being tough, meaning that the load does not decrease even when the deformation angle becomes large. In other words, by combining adhesive and nails, a hybrid horizontal structural surface is created that makes use of the characteristics of both, with adhesive providing resistance in a small load range and nails providing resistance in a large load range.

JP 2019-027234 A

The invention disclosed in Patent Document 1 is a horizontal structural member that takes advantage of the properties of adhesive and nails, and therefore has a structure that can resist a comprehensive range of loads (both small and large load ranges), and can obtain a larger floor ratio than a horizontal structural member of the same standard that is fixed only with nails (standard horizontal structural member). However, because structural nails are hammered in to resist the load, wooden materials such as horizontal surface materials, structural members, and frame members are prone to cracking due to these structural nails. In other words, when the horizontal surface materials and structural members try to flexibly deform in response to the deformation performance of the adhesive, the structural nails restrain the deformation, causing cracks in the horizontal surface materials and structural members. Also, in addition to applying the adhesive, it is necessary to hammer in the structural nails, which can be somewhat time-consuming.

The inventors of this application therefore came up with the idea of gluing and fixing horizontal plane members to structural members using only adhesive, or adhesive and temporary fixing screws or nails (temporary fixing materials until the adhesive hardens). However, it goes without saying that simply fixing with adhesive alone (or adhesive in combination with temporary fixing screws, etc.) does not allow for a horizontal structural member with a high floor multiplier.

The objective of the present invention is to solve the problems of the prior art, that is, to provide an adhesive-type load-bearing structural surface that, by satisfying certain requirements, can exhibit a high floor multiplier even when fixed only with adhesive (or with adhesive in combination with temporary fixing screws, etc.) without the need for hammering in structural nails, and can effectively resist earthquakes, etc., as well as a method for constructing it and a program that assists in determining the specified requirements (adhesive specifications).

The present invention was developed based on an unprecedented idea, focusing on the fact that horizontal surface materials are fixed to structural members using only adhesive (or adhesive in combination with temporary fixing screws, etc.) so that the "shear strain at 80% of the downward range" and "shear modulus" described below meet the specified requirements.

The adhesive load-bearing structural surface of the present invention is a load-bearing structural surface in which a horizontal surface member (or an inclined surface member) is fixed to a structural member (or a frame member) by an adhesive, and the "shear strain at 80% of the descending range" is a value equal to or greater than a predetermined threshold value, and the "shear modulus" is a value within a predetermined allowable range. Here, the "shear strain at 80% of the descending range" is the value obtained by dividing the 80% displacement amount at the descending range by the adhesive thickness, and this 80% displacement amount at the descending range is the displacement amount in the descending range of the displacement characteristic curve, among the displacement amounts corresponding to 80% strength of the maximum load on the displacement characteristic curve. On the other hand, the "shear modulus" is the value obtained by dividing the initial shear force by the initial shear strain, and this initial shear strain is the value obtained by dividing the strain when the initial shear force is applied from 0 displacement by the adhesive thickness.

The adhesive bearing structural member of the present invention can also have a shear strain of 500% or more at 80% of the downward range.

The adhesive load-bearing structural member of the present invention may also have a shear modulus of elasticity of 70 MPa or more and 500 MPa or less.

The adhesive-type load-bearing structural surface of the present invention can also be a structure in which structural members, etc. are arranged around a horizontal surface member, etc. (or around the horizontal surface member, etc. and in a central band), and the horizontal surface member, etc. is fixed with an adhesive. In this case, temporary fixing screws (or nails) are driven around the horizontal surface member, etc. These temporary fixing screws, etc. can be driven at intervals of 300 mm or more.

The method for constructing an adhesive-type load-bearing structural surface of the present invention is a method for constructing an adhesive-type load-bearing structural surface of the present invention described above, and is a method that includes a design process and a surface material fixing process. In the design process, the adhesive specifications (including at least the type of adhesive and adhesive thickness) are determined, while in the surface material fixing process, horizontal surface materials, etc. are adhesively fixed to structural members, etc. in accordance with the adhesive specifications determined in the design process.

The adhesive load-bearing structural panel construction method of the present invention can also be a method that further includes a temporary fixing step. In this case, in the surface material fixing step, structural members are placed around the horizontal surface members (or around the horizontal surface members and in the center band), and the structural members and the horizontal surface members are fixed with adhesive. In the temporary fixing step, temporary fixing screws are driven around the horizontal surface members (or around the horizontal surface members and in the center band) to temporarily fix the structural members and the horizontal surface members until the adhesive hardens.

The adhesive specification determination support program of the present invention is a program that supports the specification determination of the adhesive load-bearing surface of the present invention described above, and has a function of causing a computer to execute a displacement characteristic curve generation process, a shear strain calculation process at 80% of the downward range, a shear modulus calculation process, and a judgment process. The specifications of the adhesive load-bearing surface refer to specifications that include at least the type of adhesive and the adhesive thickness. In the displacement characteristic curve generation process, a displacement characteristic curve that shows the relationship between the displacement amount and the load of the adhesive load-bearing surface is generated, in the shear strain calculation process at 80% of the downward range, the shear strain at 80% of the downward range is calculated, and in the shear modulus calculation process, the shear modulus is calculated. In the judgment process, an adhesive specification in which the shear strain at 80% of the downward range is equal to or greater than a predetermined threshold value and the shear modulus is within a predetermined allowable range is judged to be an appropriate specification.

The adhesive-type load-bearing structural wall, the method for constructing the adhesive-type load-bearing structural wall, and the adhesive specification determination support program of the present invention have the following effects.
(1) It is possible to obtain a structure that exhibits a significantly higher floor ratio than the strength-bearing structural components of the prior art.
(2) It can be completed by simply applying adhesive, or by simply installing temporary fastening screws or the like and then applying adhesive, meaning that it can be constructed extremely easily.
(3) Various adhesives can be used by appropriately designing the adhesive thickness.

FIG. 13 is an exploded perspective view showing a schematic diagram of a part of a horizontal structural plane in the case of a floor. (a) is an exploded perspective view showing a schematic of a portion of a horizontal roof structural component in which a roof surface material is fixed onto a purlin member and a rafter, and (b) is an exploded perspective view showing a schematic of a portion of a horizontal roof structural component in which a roof surface material is fixed onto a climbing beam member. (a) is a plan view showing the back side of a horizontal surface material on which fixed areas are set, and (b) is a cross-sectional view showing a horizontal structural surface fixed in a river-shape. A plan view showing the back side of a horizontal surface member having intermediate fixing regions set in two places in the middle portion. FIG. 11 is a graph showing an example of an envelope. FIG. 4 is a graph showing an example of a displacement characteristic curve. A model diagram explaining the shear modulus. A result table summarizing the test cases and test results. (a) is an envelope diagram obtained as a result of an in-plane shear test conducted on the load-bearing structural surface of CASE 1; (b) is an envelope diagram obtained as a result of an in-plane shear test conducted on the load-bearing structural surface of CASE 2; and (c) is an envelope diagram obtained as a result of an in-plane shear test conducted on the load-bearing structural surface of CASE 3. (d) is an envelope diagram obtained as a result of an in-plane shear test conducted on the load-bearing structural surface of CASE 4, (e) is an envelope diagram obtained as a result of an in-plane shear test conducted on the load-bearing structural surface of CASE 5, and (f) is an envelope diagram obtained as a result of an in-plane shear test conducted on the load-bearing structural surface of CASE 6. (g) is an envelope diagram obtained as a result of an in-plane shear test conducted on the load-bearing structural surface of CASE 7; (h) is an envelope diagram obtained as a result of an in-plane shear test conducted on the load-bearing structural surface of CASE 8; and (i) is an envelope diagram obtained as a result of an in-plane shear test conducted on the load-bearing structural surface of CASE 9. FIG. 2 is a flow chart showing the flow of the main steps of the method for constructing an adhesive-type load-bearing structural panel of the present invention. 1A is an explanatory diagram mainly showing the specifications of beam materials among the specimens used in the in-plane shear test, and FIG. 1B is an explanatory diagram mainly showing the specifications of horizontal plane materials among the specimens used in the in-plane shear test. A graph showing the envelope of a horizontal structural member in which a horizontal plane member is fixed to a beam member by nail members.

An example of the adhesive bearing structural wall of the present invention, a method for constructing an adhesive bearing structural wall, and an adhesive specification determination support program will be explained with reference to the figures.

1. Definitions Before describing the embodiments of the present invention, the following definitions of terms used herein are provided.

(Horizontal surface material)
Here, the board material forming the floor base is called the "floor surface material", the board material forming the horizontal structural surface of the roof is called the "roof surface material", and the floor surface material and the roof surface material are collectively called the "horizontal surface material". The horizontal surface material is manufactured using various materials such as solid wood, plywood (including structural plywood), CLT material (cross laminated timber), laminated veneer lumber (LVL), molded fiberboard (MDF: medium density fiberboard), etc. In particular, structural plywood is suitable as a horizontal surface material because the strength difference in the arrangement direction is small. In addition, if the horizontal surface material is made to a thick specification (24 mm or more for structural plywood), the shear deformation of the surface material during shear deformation can be suppressed.

(Support material)
For the sake of convenience, we will refer to wire materials (materials whose axial dimensions are extremely large compared to their cross-sectional dimensions) that support horizontal surface materials as "support materials." In other words, support materials are a general term for structural members, frame materials, girths and floor beams installed around the perimeter of the floor, floor joists placed in the middle of the floor, purlins and climbing beams used for the roof, and joists and supporting beams that are placed perpendicular to these floor joists. Types of wood materials such as general lumber, laminated lumber, and LVL can be used as support materials.

(Structural surface)
As shown in Fig. 1 and Fig. 2, the frame structure in which the floor material 100 is fixed on the support material 200 is referred to as the "load-bearing structural surface". As mentioned above, the horizontal surface material 100 is a general term for the floor material 100F and the roof material 100R. Therefore, the structure in which the floor material 100F is fixed on the support material 200 as shown in Fig. 1 is specifically referred to as the "floor load-bearing structural surface", and the structure in which the roof material 100R is fixed on the support material 200 as shown in Fig. 2 is specifically referred to as the "roof load-bearing structural surface". In other words, the load-bearing structural surface can be a general term for the floor load-bearing structural surface and the roof load-bearing structural surface. The floor load-bearing structural surface can be a structure in which the floor material 100F is fixed on the support material 200, which is the girth 210, the floor joist 220, and the joist 230, as shown in Fig. 1, for example. One of the roof load-bearing structural members can be, for example, a structure in which roof surface material 100R is fixed onto purlin material 240 and rafters 250, which are supporting materials 200, as shown in Figure 2(a), or a structure in which roof surface material 100R is fixed onto climbing beam material 260, which is supporting material 200, as shown in Figure 2(b).

(Adhesion specifications for load-bearing structural surfaces)
The adhesion specifications of the load-bearing structural surface are literally the specifications for adhesively fixing the horizontal surface material 100 and the supporting material 200, and include at least the type of adhesive and the adhesive thickness, and may also include the application area and the driving pitch of the "temporary fixing screws, etc." described later. Note that the specifications of the horizontal surface material 100 and the supporting material 200 for the adhesion specifications of the load-bearing structural surface are the result of the selection of various elements including their materials, dimensions, and shapes.

(Structural screws, temporary fixing screws, etc.)
For convenience, the general term for fasteners such as screws, iron round nails (N nails, CN nails), screw nails, and screws that are driven into the horizontal plane member 100, etc., will be referred to as "screws, etc." Furthermore, screws that structurally (permanently, so to speak) connect the horizontal plane member 100 and the supporting member 200 will be specifically referred to as "structural screws, etc." In contrast, screws that are used temporarily (temporarily, so to speak) until the adhesive hardens will be specifically referred to as "temporary screws, etc." In other words, structural screws, etc. are structural members that are expected to function to connect the horizontal plane member 100 and the supporting member 200 at least for the period during which the load-bearing structural surface is in use, while temporary screws, etc. are members that are not expected to have any particular structural function once the adhesive hardens.

(River-shaped layout)
The "river-shaped form" is one of the forms for fixing the horizontal plane member 100 to the support member 200. FIG. 3 is a diagram for explaining this river-shaped form, in which (a) is a plan view showing the back side (lower surface side) of the horizontal plane member 100, and (b) is a cross-sectional view showing the load-bearing structural surface fixed in the river-shaped form. When fixing in the river-shaped form, an end fixing region 110 and an intermediate fixing region 120 are set on the horizontal plane member 100 as shown in FIG. 3(a). As can be seen from FIG. 3(b), the end fixing region 110 and the intermediate fixing region 120 are strip-shaped regions set in the range of the horizontal plane member 100 that is grounded on the support member 200, and therefore the end fixing region 110 and the intermediate fixing region 120 set on one horizontal plane member 100 are set to be approximately parallel (including parallel). In addition, in Figure 3, only one intermediate fixing area 120 is set for one horizontal plane member 100, but when two or more support members 200 are placed in between, two or more intermediate fixing areas 120 are set as shown in Figure 4 (two in this figure).

(Envelope)
The envelope curve is a widely known graph, as shown in "Allowable Stress Design for Wooden Frame Construction Houses" as mentioned above, and is a curve that shows the relationship between the load and the deformation angle obtained from the in-plane shear test on the bearing surface. Specifically, the upper end of the bearing surface in a vertical position is subjected to a stepwise load (alternating positive and negative loads are applied repeatedly) until the deformation angle is set to a preset value, and the curve that connects the results obtained at each loading step is the envelope curve.

Fig. 5 is a graph showing an example of an envelope curve. In general, an envelope curve is drawn with the deformation angle on the horizontal axis and the load on the vertical axis, and _Pmax shown in the figure is called the maximum load, _Py is called the yield strength, _Pu is called the ultimate strength, and _δu is called the ultimate deformation angle. Among these, the ultimate deformation angle _δu is set to the smaller value of either the deformation angle on the envelope curve at which the load becomes _0.8Pmax after the maximum load _Pmax is reached, or 1/15 rad.

(Displacement characteristic curve)
The displacement characteristic curve is a graph showing the relationship between the load and the amount of displacement obtained by performing an in-plane shear test on a load-bearing structural member. As shown in Fig. 6, this displacement characteristic curve is an upwardly convex curve, and therefore, with the maximum load _Pmax as a boundary, the load increases on the small displacement side (left side in the figure) (hereinafter referred to as the "increasing region"), and the load decreases on the large displacement side (right side in the figure) (hereinafter referred to as the "decreasing region"). In the increasing region and the decreasing region, a load of 80% of the maximum load _Pmax ( _0.8Pmax ) appears. For convenience, the 80% load appearing in the decreasing region is referred to as the "80% load in the decreasing region" and the displacement at which the load is 80% in the decreasing region is referred to as the "80% displacement in the decreasing region".

(shear modulus)
FIG. 7 is a model diagram for explaining the shear modulus G. As shown in this figure, the shear modulus G is obtained by applying an initial shear force τ to a test specimen in which two adherends are fixed with an adhesive. The method for obtaining the shear modulus G will be specifically described below. A test specimen in which upper and lower adherends arranged approximately horizontally are fixed with an adhesive is prepared, and a value of the initial displacement δ (for example, the initial displacement δ = 0.3 mm, etc.) is set in advance. Then, with the lower adherend fixed, an initial shear force τ is applied to the upper adherend in an approximately horizontal direction until the upper adherend changes from 0 displacement to the initial displacement δ. The value obtained by dividing the initial shear force τ obtained as a result by the initial shear strain γ is the shear modulus G. The initial shear strain γ is the value obtained by dividing the initial displacement δ by the adhesive thickness h.

(Floor multiplier)
The floor factor is the short-term allowable shear strength calculated based on the envelope curve divided by the conversion value 1.96 (kN/m) mentioned above. The short-term allowable shear strength P _a is calculated based on the short-term standard shear strength P ₀ as shown in "Allowable Stress Design of Wooden Frame Construction Houses", and the short-term standard shear strength P ₀ is determined by the smallest value among the values obtained as follows.
(a) Yield strength _Py
(b) Ultimate strength P _u × 0.2/D _s (D _s is the structural characteristic coefficient)
(c) Maximum load P _max ×2/3
(d) Strength at specific deformation

2. Adhesive Load-bearing Structural Surface Next, the adhesive load-bearing structural surface of the present invention will be described.

The adhesive load-bearing structural surface of the present invention is an adhesive load-bearing structural surface in which a horizontal plane member 100 and a supporting member 200 are adhesively fixed. The adhesive load-bearing structural surface of the present invention can be in a "river-shaped" configuration in which end fixing regions 110 and middle fixing regions 120 are set and then adhesively fixed, as shown in Figures 3 and 4, or in a so-called "square-shaped" configuration in which the entire periphery of the horizontal plane member 100 is fixed with adhesive. In addition, the horizontal plane member 100 and supporting member 200 can be fixed only with adhesive, or can be fixed using a combination of adhesive and temporary fixing screws, etc.

The adhesive load-bearing structural member of the present invention must satisfy two requirements. The first is that the shear strain at 80% of the descending range is equal to or greater than a predetermined threshold (hereinafter referred to as the "strain threshold"). The inventors of the present invention have confirmed through various tests that a high-floor-multiplier adhesive load-bearing structural member can be obtained by setting this strain threshold at a value of 500% or more. The second is that the shear modulus is within a predetermined allowable range (hereinafter referred to as the "allowable range of shear modulus"). The inventors of the present invention have confirmed through various tests that a high-floor-multiplier adhesive load-bearing structural member can be obtained by setting this allowable range of shear modulus at a value of 70 MPa or more and 500 MPa or less (500%).

(Test Example)
The results of the actual test are explained below. As shown in FIG. 8, seven load-bearing structural surfaces (CASE 1 to CASE 7) with different adhesive specifications were prepared, and an in-plane shear test was performed on each of them. For reference, tests were also performed on CASE 8 (structural screws spaced 100 mm apart) and CASE 9 (structural screws spaced 75 mm apart) in which the horizontal surface material 100 and the supporting material 200 were fixed only with structural screws without using any adhesive. The adhesives a to d (FIG. 8) used in this test each have the following characteristics. In this test, the "strain threshold" is set to 500%, and the "allowable range of shear modulus" is set to 70 MPa or more and 500 MPa or less.
(Adhesive a) Has high extensibility and medium adhesive strength. (Adhesive b) Has the same degree of extensibility as adhesive a, but has inferior adhesive strength to adhesive a. (Adhesive c) Has higher strength and higher extensibility than adhesive a. (Adhesive d) Has high strength but is brittle, and has the least extensibility of the adhesives a to d groups.

CASE 1 is a test specimen in which the horizontal plane member 100 and the support member 200 are fixed with adhesive a with a thickness of 0.3 mm, and temporary fixing screws or the like are driven in at 100 mm intervals. Figure 9 (a) shows the envelope curve obtained as a result of an in-plane shear test on the strength-bearing structural surface of CASE 1. As shown in Figure 8, the strength-bearing structural surface of CASE 1 shows a shear strain of 1065% at 80% of the descending range, which exceeds the strain threshold of 500%, and therefore satisfies the first requirement. In addition, the shear modulus of elasticity is 175.9 MPa, which is within the allowable range of shear modulus of elasticity of 70 to 500 MPa, and therefore also satisfies the second requirement. In other words, the strength-bearing structural surface of CASE 1 was recognized as an adhesive-type strength-bearing structural surface of the present invention. The bed ratio is 4.76, which is higher than the bed ratios of conventional technologies such as CASE 8 (bed ratio 3.19) and CASE 9 (bed ratio 3.92).

CASE 2 is a test specimen in which the horizontal plane member 100 and the support member 200 are fixed with adhesive a with a thickness of 0.9 mm, and temporary fixing screws or the like are driven in at 100 mm intervals. Figure 9 (b) shows the envelope curve obtained as a result of an in-plane shear test on the strength-bearing structural surface of CASE 2. As shown in Figure 8, the strength-bearing structural surface of CASE 2 has a shear strain of 733% at 80% of the descending range, which exceeds the strain threshold of 500%, and therefore satisfies the first requirement. In addition, the shear modulus is 298.1 MPa, which is within the allowable range of shear modulus of 70 to 500 MPa, and therefore also satisfies the second requirement. In other words, the strength-bearing structural surface of CASE 2 was recognized as an adhesive-type strength-bearing structural surface of the present invention. The bed ratio is 5.55, which is higher than the bed ratios of conventional technologies such as CASE 8 (bed ratio 3.19) and CASE 9 (bed ratio 3.92).

CASE 3 is a test specimen in which the horizontal plane member 100 and the support member 200 are fixed with adhesive a with a thickness of 0.9 mm, and temporary fixing screws or the like are driven in at 300 mm intervals. Figure 9 (c) shows the envelope curve obtained as a result of an in-plane shear test on the strength-bearing structural surface of CASE 3. As shown in Figure 8, the strength-bearing structural surface of CASE 3 shows a shear strain of 733% at 80% of the descending range, which exceeds the strain threshold of 500%, and therefore satisfies the first requirement. In addition, the shear modulus of elasticity is 298.1 MPa, which is within the allowable range of shear modulus of elasticity of 70 to 500 MPa, and therefore also satisfies the second requirement. In other words, the strength-bearing structural surface of CASE 3 was recognized as an adhesive-type strength-bearing structural surface of the present invention. The floor ratio is 6.38, which is higher than the conventional techniques such as CASE 8 (floor ratio 3.19) and CASE 9 (floor ratio 3.92). Comparing CASE 2 and CASE 3, CASE 3, which has a wider spacing between temporary fixing screws (100 mm in CASE 2 and 300 mm in CASE 3), has a higher floor ratio. This shows that temporary fixing screws, unlike structural screws, do not contribute to the floor ratio.

CASE 4 is a test specimen in which the horizontal plane member 100 and the support member 200 are fixed with adhesive b with a thickness of 0.3 mm, and temporary fixing screws or the like are driven in at 100 mm intervals. Figure 10 (d) shows the envelope curve obtained as a result of an in-plane shear test on the strength-bearing structural surface of CASE 4. As shown in Figure 8, the strength-bearing structural surface of CASE 4 shows a shear strain of 1132% at 80% of the descending range, which exceeds the strain threshold of 500%, and therefore satisfies the first requirement. In addition, the shear modulus of elasticity is 86.6 MPa, which is within the allowable range of shear modulus of elasticity of 70 to 500 MPa, and therefore also satisfies the second requirement. In other words, the strength-bearing structural surface of CASE 4 was recognized as an adhesive-type strength-bearing structural surface of the present invention. The bed ratio is 4.85, which is higher than the bed ratios of conventional technologies such as CASE 8 (bed ratio 3.19) and CASE 9 (bed ratio 3.92).

CASE 5 is a test specimen in which the horizontal plane member 100 and the support member 200 are fixed with adhesive b with a thickness of 0.9 mm, and temporary fixing screws or the like are driven in at 100 mm intervals. Figure 10(e) shows the envelope curve obtained as a result of an in-plane shear test on the strength-bearing structural surface of CASE 5. As shown in Figure 8, the strength-bearing structural surface of CASE 5 has a shear strain of 599% at 80% of the descending range, which exceeds the strain threshold of 500%, and therefore satisfies the first requirement. In addition, the shear modulus is 320.7 MPa, which is within the allowable range of shear modulus of 70 to 500 MPa, and therefore also satisfies the second requirement. In other words, the strength-bearing structural surface of CASE 5 was recognized as an adhesive-type strength-bearing structural surface of the present invention. The bed ratio is 4.60, which is higher than the bed ratios of conventional technologies such as CASE 8 (bed ratio 3.19) and CASE 9 (bed ratio 3.92).

CASE 6 is a test specimen in which the horizontal plane member 100 and the support member 200 are fixed with adhesive c with a thickness of 0.3 mm, and temporary fixing screws or the like are driven in at 100 mm intervals. Figure 10(f) shows the envelope curve obtained as a result of an in-plane shear test on the strength-bearing structural surface of CASE 6. As shown in Figure 8, the strength-bearing structural surface of CASE 6 shows a shear strain of 998% at 80% of the descending range, which exceeds the strain threshold of 500%, and therefore satisfies the first requirement. In addition, the shear modulus of elasticity is 250.0 MPa, which is within the allowable range of shear modulus of elasticity of 70 to 500 MPa, and therefore also satisfies the second requirement. In other words, the strength-bearing structural surface of CASE 6 was recognized as an adhesive-type strength-bearing structural surface of the present invention. The bed ratio is 5.74, which is higher than the bed ratios of conventional technologies such as CASE 8 (bed ratio 3.19) and CASE 9 (bed ratio 3.92).

CASE 7 is a test specimen in which the horizontal plane member 100 and the supporting member 200 are fixed with adhesive d with a thickness of 0.3 mm, and temporary fixing screws or the like are driven in at 250 mm intervals. Figure 11 (g) shows the envelope curve obtained as a result of an in-plane shear test on the strength structural surface of CASE 7. As shown in Figure 8, the strength structural surface of CASE 7 shows a shear strain of 252% at 80% of the descending range, which does not exceed the strain threshold of 500%, and therefore does not meet the first requirement. In addition, the shear modulus is 337.6 MPa, which is within the allowable range of shear modulus of 70 to 500 MPa, and therefore meets the second requirement. In other words, the strength structural surface of CASE 7 is not an adhesive strength structural surface of the present invention. The floor ratio is 2.40, which is lower than the floor ratios of conventional technologies such as CASE 8 (floor ratio 3.19) and CASE 9 (floor ratio 3.92). In this way, even if a load-bearing structural surface is fixed using a combination of adhesive and temporary fixing screws, if it does not meet the first and second requirements, it is not an adhesive load-bearing structural surface of the present invention, and its floor ratio is also low.

3. Method for constructing adhesive-type load-bearing structural surfaces Next, the method for constructing adhesive-type load-bearing structural surfaces of the present invention will be described with reference to FIG. 12. The method for constructing adhesive-type load-bearing structural surfaces of the present invention is the method for constructing the adhesive-type load-bearing structural surfaces of the present invention described up to this point. Therefore, we will avoid overlapping explanations with those explained in "2. Adhesive Load-bearing Structural Surfaces" and only explain the contents unique to the method for constructing adhesive-type load-bearing structural surfaces. In other words, the contents not described here are the same as those already explained, including "1. Definitions". The method for constructing adhesive-type load-bearing structural surfaces of the present invention can also be implemented in the case of fixing in a square shape, but for convenience, we will explain the case of fixing in a river shape here.

Figure 12 is a flow diagram showing the flow of the main steps in the method of constructing an adhesive load-bearing structural panel of the present invention. As shown in this figure, the method mainly involves two steps: the design step (Step 100) and the horizontal surface member fixing step (Step 200).

(Design process)
In the design process, first, the adhesion specifications of the load-bearing structural surfaces, i.e., the specifications of the adhesive, are planned (Step 110). At this time, it is advisable to plan the specifications of the horizontal plane member 100 and the support member 200 as well. Then, a test shown in FIG. 7 (hereinafter, simply referred to as a "shear strain test") is conducted on a specimen with the planned adhesion specifications to obtain the shear modulus G, and the above-mentioned in-plane shear test is conducted on the load-bearing structural surfaces with the planned adhesion specifications, and the resulting displacement characteristic curve is confirmed (Step 120).

When the shear modulus G is obtained by the shear strain test and the displacement characteristic curve is obtained by the in-plane shear test, the shear strain at 80% of the descending range obtained from the displacement characteristic curve is compared with the strain threshold value to determine the first requirement, and the shear modulus G is compared with the allowable range of the shear modulus to determine the second requirement (Step 130). At this time, the envelope is obtained based on the in-plane shear test, and the wall factor can also be calculated. Then, when both the first requirement and the second requirement are satisfied, the strength structural surface according to the adhesive specification is judged to be the adhesive type strength structural surface of the present invention, and when either the first requirement or the second requirement is not satisfied, the strength structural surface according to the specification is judged to be not the adhesive type strength structural surface of the present invention, and the adhesive specification is planned again (Step 110), and testing and confirmation are performed (Step 120). In addition, when the wall factor is calculated, it can be determined that the wall factor is an adhesive-type load-bearing structural member of the present invention when it satisfies all of the first, second, and third requirements, including the ``third requirement'' that ``the wall factor is equal to or greater than a predetermined wall factor threshold value (e.g., the wall factor obtained by conventional construction methods).''

(Surface material fixing process)
In the horizontal member fixing process, first, the end fixing region 110 and the intermediate fixing region 120 are positioned on the back surface (lower surface) of the horizontal member 100 (Step 210), and adhesive is applied to the end fixing region 110 and the intermediate fixing region 120 (Step 220). At this time, in the case where the adhesive-type load-bearing structural surface is in a square shape, the application of adhesive to the intermediate fixing region 120 is omitted. Instead of applying adhesive to the horizontal member 100, adhesive may be applied to the front surface (upper surface) of the support member 200 (Step 220), in which case the positioning process of the end fixing region 110 and the intermediate fixing region 120 (Step 210) can be omitted.

After applying adhesive to the end fixing area 110 and intermediate fixing area 120 (or the surface of the support material 200) on the back surface of the horizontal plane material 100, the horizontal plane material 100 is set up so that the end fixing area 110 and intermediate fixing area 120 are placed on the support material 200 (Step 230). Then, temporary fixing screws are driven in at a specified pitch in the end fixing area 110 and intermediate fixing area 120 on the surface of the horizontal plane material 100 (Step 240), and the adhesive is allowed to take effect, completing the adhesive load-bearing structural surface.

4. Adhesive specification determination support program The adhesive specification determination support program of the present invention will be described. Note that the adhesive specification determination support program of the present invention is a program that determines the specifications of the adhesive load-bearing structural surfaces described so far, and therefore, we will avoid explanations that overlap with the contents explained in "2. Adhesive load-bearing structural surfaces" and only explain the contents unique to the adhesive specification determination support program. Contents not described here are the same as those already explained, including "1. Definitions."

The adhesive specification determination support program of the present invention is a program that causes a computer to execute a function for determining the specifications of adhesive load-bearing structural members, and can be effectively used in the design process of a construction method for adhesive load-bearing structural members. More specifically, when an operator inputs the results of a shear strain test and an in-plane shear test according to the planned adhesive specifications, the adhesive specification determination support program of the present invention causes a computer to execute a process for generating a displacement characteristic curve (displacement characteristic curve generation process), a process for calculating the shear strain at 80% of the downward range (shear strain calculation process at 80% of the downward range), and a process for calculating the shear modulus (shear modulus calculation process). At this time, the computer can also execute a process for calculating an envelope based on the in-plane shear test and a process for calculating the wall factor (wall factor calculation process). Then, when both the first and second requirements are met, the computer executes a process (determination process) to determine that the strength-bearing structural surface based on the adhesive specifications is an adhesive-type strength-bearing structural surface of the present invention, and when either the first or second requirement is not met, the strength-bearing structural surface based on the specifications is not an adhesive-type strength-bearing structural surface of the present invention. When the wall factor is calculated, it can also be determined to be an adhesive-type strength-bearing structural surface of the present invention when the first, second, and third requirements are all met, including the "third requirement" that "the wall factor shows a value equal to or greater than a predetermined wall factor threshold value (e.g., the wall factor using a conventional construction method)."

The adhesive-type load-bearing structural surface, the method for constructing an adhesive-type load-bearing structural surface, and the adhesive specification determination support program of the present invention can be used in a variety of wooden buildings, including detached wooden houses, as well as schools, kindergartens, offices, and public facilities. They are particularly effective in wooden buildings with large open spaces such as atriums.

100 Horizontal surface material 100F Floor surface material (horizontal surface material)
100R Roof surface material (horizontal surface material)
110 (of horizontal surface member) end fixing region 120 (of horizontal surface member) middle fixing region 200 support member 210 girth (support member)
220 Floor beam (support material)
230 Joist (support material)
240 Purlin material (support material)
250 Rafters (supporting material)
260 Climbing material (supporting material)

Claims (6)

A load-bearing structural surface in which horizontal or inclined surface materials are fixed to structural members or frame members by adhesive,
The horizontal or inclined surface material is fixed to the structural member or the frame member with an adhesive specification in which the shear strain at 80% of the downward range in the displacement characteristic curve obtained by performing an in-plane shear test on the adhesive load-bearing structural member is 500% or more, and the shear modulus is 70 MPa or more and 500 MPa or less ,
The shear strain at 80% of the downward displacement is a value obtained by dividing the 80% displacement of the downward displacement by the adhesive thickness,
The 80% displacement in the descending region is a displacement in the descending region of the displacement characteristic curve among the displacements corresponding to 80% strength of the maximum load of the displacement characteristic curve,
The shear modulus is the initial shear force divided by the initial shear strain,
The initial shear strain is the initial displacement divided by the adhesive thickness.
A bonded load-bearing structural surface characterized by: The structural members or frame members arranged around the horizontal surface material or the inclined surface material, or around and in the center band of the horizontal surface material or the inclined surface material, and the horizontal surface material or the inclined surface material are fixed to each other by the adhesive,
A temporary fixing screw or nail is driven into the periphery of the horizontal surface material or the inclined surface material.
2. The adhesive-type load-bearing structural member according to claim 1 . The temporary fixing screws or nails are driven at intervals of 300 mm or more.
3. The adhesive-type load-bearing structural member according to claim 2 . A method for constructing an adhesive-type load-bearing structural surface in which a horizontal surface material or an inclined surface material is fixed to a structural member or a frame member by an adhesive, comprising the steps of:
A design process for determining adhesive specifications including the type of adhesive and adhesive thickness;
A surface material fixing process for adhesively fixing the horizontal surface material or the inclined surface material to the structural member or the frame member in accordance with the adhesive specifications determined in the design process,
In the design step, the adhesive specifications are determined so that the shear strain at 80% of the descending region is equal to or greater than a predetermined threshold value and the shear modulus is within a predetermined allowable range;
The shear strain at 80% of the downward displacement is a value obtained by dividing the 80% displacement of the downward displacement by the adhesive thickness,
The 80% downward displacement is a displacement in a downward region of the displacement characteristic curve among the displacements corresponding to 80% strength of the maximum load of the displacement characteristic curve obtained as a result of performing an in-plane shear test on the adhesive load -bearing structural panel,
The shear modulus is the initial shear force divided by the initial shear strain,
The initial shear strain is the initial displacement divided by the adhesive thickness.
A method for constructing an adhesive load-bearing structural surface. In the surface material fixing step, the structural members or frame members are arranged around the horizontal surface material or the inclined surface material, or around and in a central band of the horizontal surface material or the inclined surface material, and the structural members or frame members and the horizontal surface material or the inclined surface material are fixed together with the adhesive ,
The method further includes a temporary fixing step of driving temporary fixing screws or nails into the periphery of the horizontal surface material or the sloping surface material, or into the periphery and center band of the horizontal surface material or the sloping surface material, in order to temporarily fix the structural member or the frame member and the horizontal surface material or the sloping surface material until the adhesive hardens.
5. A method for constructing an adhesive load-bearing structural panel according to claim 4 . A program for causing a computer to execute a function of supporting the determination of adhesive specifications for adhesive-type load-bearing structural members in which horizontal or inclined surface materials are fixed to structural members or frame members by adhesive,
The adhesive specification includes the type of adhesive and the adhesive thickness,
A displacement characteristic curve generation process for generating a displacement characteristic curve showing the relationship between the displacement and the load obtained as a result of performing an in-plane shear test on the adhesive load-bearing structural member ;
A shear strain calculation process for calculating a shear strain at 80% of the downward region by dividing the amount of displacement at 80% of the downward region in the displacement characteristic curve by the adhesive thickness;
A shear modulus calculation process for calculating a shear modulus by dividing the initial shear force by the initial shear strain;
a judgment process for judging, as an appropriate specification, the adhesive specification in which the shear strain at 80% of the descending region is equal to or greater than a predetermined threshold value and the shear modulus is within a predetermined allowable range;
The 80% displacement in the descending region is a displacement in the descending region of the displacement characteristic curve among the displacements corresponding to 80% strength of the maximum load of the displacement characteristic curve,
The initial shear strain is the initial displacement divided by the adhesive thickness.
A bonding specification determination support program.

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