JPH10280556A - Reinforcing method of connecting section of wood in building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the rotting of connecting sections while improving the earthquake-resistant performance of the connecting sections by filling a section between the mutual connecting surfaces of wood with adhesives having a low elastic modulus after curing. SOLUTION: In a connection, a tenon section 5 formed at the end section of a beam 4 is fitted into a bottomed mortice 3 formed to a column 2, and the beam 4 is bonded with the column 2 at a right angle. A section between the connecting surfaces of the column 2 and the beam 4 is filled with adhesives 6 at that time. The elastic modulus of the adhesives 6 after curing is set in 10<5> -10<10> dyne/cm<2> . Consequently, the follow-up properties of the adhesives to the displacement of connecting sections can be displayed sufficiently. Accordingly, the lowering of the strength of the connecting sections due to a change with time is inhibited, and the reinforcing method of the connecting sections can contribute to an improvement in durability and earthquake-resistant performance in the building.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for strengthening a wood joint, particularly a tenon, in a building.

[0002]

2. Description of the Related Art In a wooden building, in order to connect wood in a longitudinal direction or an orthogonal direction, various types of connecting structures are used depending on a use site or the like. For example, step joints, stool dovetail joints, sickle sickle joints, etc. are used in joints where wood is joined in the longitudinal direction, and migrating jaws, lower sickles, large inserts are used in joints where wood is joined in the orthogonal direction. Etc. are adopted. In addition, it is also common practice to assemble metal fittings such as braces, short metal pieces, and bolts to these joints to further increase the joint strength at the joints. Furthermore, for example, in existing wooden buildings designated as important cultural properties, etc., in order to reinforce the joint,
There is also known a technique in which a resin material such as an epoxy resin or an acrylic resin is injected or applied to the joint to increase the joint strength of the joint.

[0003]

While investigating the reason for the collapse of a wooden house collapsed in the Great Hanshin Earthquake, the inventors found that tenons formed on pillars and beams fell out of the mortise. There are many houses and houses where the tenon rots and breaks, or is completely lost due to rot, and it has been found that the reduced strength of the joints is one of the causes of collapse. Also, even in a house where the connecting part is reinforced with braces, short metal parts, bolts, or other metal fittings, the metal fittings and nails for fixing it are rusted, or these metal fittings are fixed near the joint It was found that the metal fittings were easy to fall off due to the decay of the joint. On the other hand, as in important cultural properties, it is conceivable to fill the joint with a resin material to prevent decay in the joint and to increase the bond strength. As a result of evaluating the seismic performance by filling the resin, although the resin material used conventionally can prevent the strength of the joint from decreasing due to decay, the cured adhesive itself has almost no elasticity, There has been a problem that when vibration is applied, the bonded portion breaks relatively easily. That is, almost no improvement in seismic performance due to the bonding of the woods was expected.

It is an object of the present invention to provide a method for effectively preventing decay at a joint portion of wood, improving seismic performance at the joint portion, and strengthening the joint portion of wood in a building which is easy to construct. It is.

[0005]

According to a first aspect of the present invention, there is provided a method for strengthening a joint of wood in a building, wherein an adhesive having a low elastic modulus after curing is filled between the joining surfaces of the wood in the building. Things. As described above, since the adhesive is filled between the joining surfaces of the woods, moisture is prevented from entering between the joining surfaces, and water droplets due to dew condensation enter the joining surfaces along the columns and walls. This prevents the joint from spoiling. In addition, since the wood pipes and temporary pipes are sealed by the adhesive, even if dew condensation occurs or moisture enters between the joining surfaces, moisture will not enter the wood inside the pipes or temporary pipes. With the adhesive cured in step (1), it is surely prevented. Furthermore, since a material having a low elastic modulus is used as the adhesive, the adhesive is displaced following the displacement of the joint portion due to vibration such as an earthquake, and the breakage of the bonded portion is effectively prevented. That is, the vibration energy is effectively absorbed by the adhesive, the seismic resistance of the building is improved, and the decay of the joint after the earthquake caused by the breakage of the bonded part is also effectively prevented.

[0006] As described in claim ² , it is preferable that the elastic modulus of the adhesive after curing is set to 10 ⁵ to 10 ¹⁰ dyne / cm ² . By setting the elastic modulus in this manner, it is possible to sufficiently exhibit the followability of the adhesive to the displacement of the joint.

According to a third aspect of the present invention, the adhesive is housed in a bag, and the bag is broken by a load at the time of joining the wood, so that the adhesive is filled in the joint surface. As described in 4, it is preferable that two-part curable adhesives are individually contained in the bag body one by one. In other words, by storing the adhesive in the bag body in this way, it is possible to fill the adhesive between the joint surfaces of the wood while preventing the finger from being stained and the adhesive from adhering to other objects. This makes it possible to perform the filling operation more efficiently than in the case of filling by coating or injection.

[0008] As described in claim 5, it is preferable to add a preservative to the adhesive. In other words, by adding the preservative, the propagation of putrefactive bacteria on the bonding surface can be more effectively prevented.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2,
In the case of connecting the woods constituting the pillars and beams of the building in series or by crossing them together, they are connected via a joint as shown in FIG. 1 or a connection as shown in FIG. Techniques are commonly employed. FIGS. 1 (a) to 1 (c) show a step joint, a dovetail joint, and a sickle joint, which are configured so as to directly connect wood pieces.
(E) shows the joint of the beam by sandwiching the plywood and the joint of the beam by the attachment plate, which are configured so that the woods are indirectly connected to each other by using the hardware. In addition, FIG.
FIG. 2C shows a migrating chin, a lower sickle, and a large container, which are configured so as to directly connect wood to each other.
(D) to (f) show the joining of the beams by the receiving metal fitting, the joining of the beams by the T-shaped hardware, and the joining of the beams by the angle with the stiffener. However, the joints and connections may have a configuration other than those shown in the drawings according to the application site in the building, or may be reinforced through hardware such as braces, short hardware, or bolts. .

The present invention relates to a reinforcing method for strengthening a joint portion by filling an adhesive between woods or a joint surface between wood and metal at a joint or a joint, as described above. Although it can be applied to various kinds of joints and connections, a case where the present invention is applied to a connection 1 having a configuration as shown in FIGS. 3 and 4 will be described.

The connection 1 is formed by fitting a tenon portion 5 formed at the end of a beam 4 into a bottomed tenon hole 3 formed in a pillar 2.
The beam 4 is joined to the pillar 2 at right angles, and the adhesive 6 is applied to the pillar 2
Between the connecting surfaces of the beam and the beam 4. However, adhesive 6
May be provided on the entire surface of the joint surface, or may be provided only on a portion where rot is likely to occur, for example, only on a fitting portion between the tenon portion 5 and the tenon hole 3.

As the adhesive 6, an adhesive whose elastic modulus after curing is adjusted to 10 ⁵ to 10 ¹⁰ dyne / cm ² is employed. That is, if the elastic modulus is larger than 10 ¹⁰ dyne / cm ² , vibration energy due to the earthquake cannot be absorbed, and separation from the bonding interface may occur.
^If it is smaller than ⁵ dyne / cm ^{2, the} effect of reinforcing the joint cannot be expected, so that it is 10 ⁵ to 10 ¹⁰ dyne / cm ^2.
Is set to

As a specific material, it is conceivable to use an adhesive made of an elastic material having a low elastic modulus such as a silicone type, a modified silicone type, a polyurethane type, an acrylic type, and a polysulfide type. In particular, low polyurethane adhesive modulus of elasticity, in the estimated frequency of earthquakes in seismic intensity 5 to 7 (10 to 10 ⁶ Hz), the adhesive 6 is easily displaced so as to follow the variation of the gap between the bonding surfaces, This is preferable for preventing the tenon portion 5 from breaking.

Further, a preservative may be added to the adhesive 6 in order to more effectively suppress the propagation of putrefactive bacteria in the joint 1. Examples of preservatives include formaldehyde condensed compounds (for example, hexahydro-1,3,5-triethyl-s-triazine and the like), aldehyde compounds, and halogenated compounds (for example, 1,2-dibromo-2,4-dicyanobutane and the like) ), Sulfur-containing compounds (eg, thiazolylsulfamide compounds), quaternary ammonium salts (eg, benzethonium chloride), phosphonium salts (eg, dialkyldimethylphosphonium salts), guanidine derivatives (eg, chlorhexidine gluconate, etc.) ), Phenolic compounds (for example, p-chloro-
m-cresol), a benzimidazole derivative, a surfactant, an amine compound, a simple metal (for example, silver, copper, chromium, titanium, or the like), or a metal complex salt substance or an inclusion compound thereof is preferable. In addition, by using natural components such as hinokitiols, tannins, chitosans and lignin as preservatives, it is possible to realize a wooden building that is friendly to the environment and the human body.

Further, the adhesive 6 may be applied directly to the bonding surface or may be injected into the mortise 3 with an injector or the like. However, as shown in FIG. When the mortise portion 5 is fitted into the mortise hole 3 by enclosing, the bag body 7 may be broken and the adhesive 6 may be filled between the joining surfaces. When a two-component curing type adhesive 6 is used as the adhesive 6, two chambers are formed in the bag body so that each of the two components (the main component and the curing agent) does not contact and mix with each other.
The adhesive 6 may be individually sealed in each room by one liquid, or two bags may be used separately or as a double bag, and the adhesive 6 may be individually sealed in each bag by one liquid. . When the adhesive 6 is sealed in the bag in this way, when filling the adhesive 6 between the joining surfaces, it is possible to prevent the finger from being stained or to adhere the adhesive 6 to other objects, and to perform the filling operation. It can be performed efficiently.

Next, a description will be given of a bending test and an impact test performed for selecting an adhesive. As the adhesive 6,
One-component moisture-curable polyurethane adhesive A1, one-component moisture-curable polyurethane adhesive A2, and two-component polysulfide-based adhesive A3 were used. The elastic modulus of each adhesive was measured. As a test piece, as shown in FIG.
Two 4 × 14 × 40 mm strips 11 are bonded in series so that the thickness of the adhesive layer is 150 μm, and 3
Various kinds of test pieces 10 were produced. Then, in a state where the vicinity of both ends of the test piece 10 is supported at two points with an interval of 60 mm, a pressing wedge is pressed against the bonding portion from above to apply 2 mm / m
For each of the bending speeds of in, 20 mm / min, and 200 mm / min, a bending test was performed to measure the adhesive strength, and an impact test was performed at a shock speed of 290 cm / s using a Charpy impact tester to reduce the adhesive strength. The measurement was performed and the test results shown in Table 1 were obtained.

[0017]

[Table 1]

As can be seen from Table 1, regarding the bending test,
The adhesive A1 has a high adhesive strength to low-speed deformation (2 mm / min), but has only an adhesive strength to high-speed deformation (200 mm / min) which is not much different from the adhesives A2 and A3 having a low elastic modulus. . Regarding the impact test,
The adhesives A2 and A3 having a lower elastic modulus than the adhesive A1 have higher or equal adhesive strength. By the way, the seismic velocity at seismic intensity 5-7 is 13-1.
It is estimated to be about 26 cm / s, and the test speed of the impact test is:
Considering that the calculated value is 290 cm / s, it is understood that the adhesive A2 is more preferable as the adhesive than the adhesives A1 and A3.

Further, for the adhesives A1 to A3, the relationship between the frequency F and the elastic modulus E was measured in order to investigate the dynamic elastic modulus near the seismic frequency, and the results as shown in FIG. 7 were obtained. As can be seen from FIG. 7, frequency 1 including seismic intensities 5 to 7
At 0 to 10 ⁶ Hz, the adhesive A2 has a lower elastic modulus than the adhesives A1 and A3, and exhibits excellent impact strength as described above. Therefore, an elastic material having a low elastic modulus is used as the adhesive. It can be said that adoption is preferable.

Next, a test performed to verify the preservative effect of the adhesive mixed with the preservative will be described. Example 1
As Nos. 4 to 4, four types of adhesives were prepared by adding 3% by weight of preservatives having the components shown in Table 2 to the above-mentioned adhesive A2, and as a comparative example, an adhesive A containing no preservative was added.
2 was prepared. Then, in accordance with the mold resistance test specified in JIS Z 2911, these five types of adhesives were individually set in close contact on an agar medium formed in a petri dish, and in the petri dish, as a wood-rotting fungus, Streptomyces oleracea,
1 ml of a suspension in which three kinds of wood rot fungi, Kawatake mushroom and Namida mushroom were mixed, was sprinkled and cultured at 26 ± 2 ° C for one week, and the state of mycelial growth was observed. Table 2 shows the observation results.
Shown along with.

[0021]

[Table 2]

As shown in Table 2, no hyphal growth was observed in Examples 1 to 4, but in the comparative example, hyphal growth was observed. It can be seen that the growth was effectively prevented.

[0023]

According to the method for strengthening a joint of wood in a building according to the first aspect, a simple method of filling an adhesive having a low elastic modulus after curing between the joining surfaces of the wood in the building. Thereby, the decay of the joint is effectively prevented, the decrease in the strength of the joint due to aging is suppressed, and the durability and the seismic performance of the building can be improved. In addition, by using an adhesive with a low elastic modulus, the vibration energy can be effectively absorbed by the adhesive, and the breakage of the bonded part can be effectively prevented. Can be effectively prevented from lowering and the joint decay after the earthquake.

According to the second aspect of the present invention, the elasticity of the adhesive after curing is properly set, so that the adhesive can follow the displacement of the joint portion, and the building has a seismic performance. Can be improved. According to the method of claims 3 and 4, it is possible to fill the space between the joining surfaces of the wood with the adhesive while preventing the finger from being stained or the adhesive of another object being attached. In addition, the filling operation of the adhesive can be efficiently performed.

According to the method described in claim 5, it is possible to more effectively prevent the growth of putrefactive bacteria on the joint surface by the preservative, and to realize a wooden building that is friendly to the environment and people.

[Brief description of the drawings]

FIG. 1 is a perspective view of various joints to which a method of strengthening a joint according to the present invention can be applied.

FIG. 2 is a perspective view of various connections to which the method for reinforcing a joint according to the present invention can be applied.

FIG. 3 is a perspective view of a connection to which the method for reinforcing a joint according to the present invention is applied.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is an explanatory view of a method of assembling the connection.

FIG. 6 is an explanatory view of a test piece.

FIG. 7 is a diagram showing a relationship between frequency and elastic modulus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Connection 2 Pillar 3 Mortise hole 4 Beam 5 Mortice part 6 Adhesive 7 Bag 10 Test piece 11 Slit mortar

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuichi Matsumoto 7-1, Akita-cho, Takatsuki-shi, Osaka Sunstar Giken Co., Ltd. (72) Inventor Akira Amano 1-26-11, Okusawa, Setagaya-ku, Tokyo (72 Inventor Kenji Sugimoto 3-3-10 Takada, Chigasaki, Kanagawa

Claims (5)

[Claims] Claims: 1. Between the connecting surfaces of wood in a building,
A method for strengthening a wood joint in a building, characterized by filling with an adhesive having a low elastic modulus after curing. 2. The elastic modulus of the adhesive after curing is 10 ⁵
Coupling portions strengthen the method of wood in 10 ¹⁰ Construction of claim 1, wherein set in dyne / cm ^2. 3. The building according to claim 1, wherein the adhesive is accommodated in a bag, and the bag is broken by a load at the time of joining the wood, and the adhesive is filled in the joint surface. How to strengthen the joints of wood. 4. The method according to claim 3, wherein the two-part curable adhesive is individually contained in the bag body one by one. 5. The adhesive according to claim 1, wherein a preservative is added to the adhesive.
The method for strengthening a joint of wood in a building according to any one of the above.