JP3661059B2 - Unbonded composite axial force member made of wood and metal parts - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
This invention belongs to the technical field of an axial force member formed by using wood as a buckling stiffener for a metal member and synthesizing both materials in an unbonded state.
[0002]
[Prior art]
Steel truss structures are often used for large spaces and large span buildings such as multipurpose domes and gymnasiums. However, since metal members such as steel and aluminum materials are bent and buckled by compressive force, it is difficult to sufficiently expect the original compressive strength (compressive yield strength) of the metal member.
[0003]
Recently, environmentally friendly architecture is also being promoted, and the design and construction of buildings using wood-based materials is expanding.
The composite material for construction described in JP-A-2001-193220 has a structure in which a laminated material is arranged on both sides of a steel plate and the steel plate and the laminated material are joined by a drift pin, and an axial force is applied to both the laminated material and the steel plate. It is explained that it will be used for “stitching”.
[0004]
The contents of the “compressive strength experiment of composite members combining wood and steel plate” presented by the inventors of the present application at the 2001 Architectural Society of Japan meeting are also made of wood as a stiffener for steel plates, and both materials are integrated by bonding. The result of the examination of the compressive properties by the full-scale test of the composite material was introduced.
An invention of an unbonded steel brace obtained by stiffening a steel brace with a steel pipe according to the previous application of the present applicant is disclosed in Japanese Patent Laid-Open No. 7-324377.
[0005]
[Problems to be solved by the present invention]
According to the research of the above-mentioned “composite member combining wood and steel plate” by the inventors of the present application, “wood is light and strong”, but the strength performance of the wood varies widely and is as uniform as steel. It ’s hard to trust. Nevertheless, in the case of so-called bond-type synthetic materials, in which steel plates and laminated materials are integrated by bonding, stud bonding, bolt bonding, drift pin bonding, etc., the wood bears part of the load borne by the synthetic material ing. That is, the wood bears a part of the axial force in addition to the stiffening action against the bending buckling of the steel plate. However, it is the intended purpose of the synthetic material that the axial force is borne by the steel material, which is inherently high in strength. It is unreasonable that wood bears an axial force as well because it uses wood for an unsuitable purpose (strength).
[0006]
In the case of the conventional bond-type synthetic material described above, the magnitude of the axial force borne by the wood depends on the degree of fixing between the wood and the steel material (joining degree = stiffness of the fixed part). However, since the degree of fixing largely depends on the indentation rigidity and processing dimensions of the wood, the uncertainty is generally high. Therefore, the bond-type synthetic material in which wood bears a part of the axial force has a double uncertainty: variation in the strength of the wood and variation in the magnitude of the axial force that the wood bears. There is a problem that the reliability of the yield strength of the synthetic material is impaired, or the design is still uneconomical in order to obtain sufficient reliability.
[0007]
In addition, in the case of a bond-type synthetic material in which a steel plate and wood, a laminated material, and the like are integrated by bonding or the like, solving various inconveniences due to differences in thermal expansion coefficients between the wood and the steel plate is also an important issue.
[0008]
In the case of an unbonded steel brace obtained by stiffening a steel brace with a steel pipe as disclosed in the above-mentioned JP-A-7-324377, the problem of “steel material is strong but heavy” is a big solution for use and transportation. Cause it to occur.
[0009]
The object of the present invention is simple structure, light weight, small size, can be implemented at low cost, excellent load bearing performance and stability against axial force, no problems caused by thermal expansion difference between wood and metal, and economical An objective is to provide an unbonded composite axial force member made of wood and metal members, which is reliable and reliable.
[0010]
[Means for Solving the Problems]
As a means for solving the above-mentioned problems of the prior art, the unbonded composite axial force member of wood and metal member according to the invention described in claim 1 is:
It is characterized in that wood is synthesized in an unbonded state in an arrangement for preventing buckling of the metal member, and both ends of the metal member protruding from the end of the wood are configured as input portions for axial force. .
[0011]
In the unbonded composite axial force member of wood and metal member according to the second aspect of the present invention, wood is superimposed on both surfaces of a metal plate, and a wood plate is placed on the side surfaces of the two woods on both sides, and the wood plate and the metal plate The two timbers on both sides of the metal plate are connected with nails or the like, and both end portions of the metal plate protruding from the end portions of the timber are configured as input portions for axial force.
[0012]
The unbonded composite axial force member of wood and a metal member according to the invention described in claim 3 is formed by superimposing wood on both sides of a metal plate, and the two woods on both sides are bound together by a plurality of bands. Both end portions of the metal plate protruding from the end portion of the wood are configured as input portions for axial force.
[0013]
The unbonded composite axial force member of wood and a metal member according to the invention described in claim 4 is provided with a through hole through which the metal tube can be passed in the wood with substantially the same shape and size as the cross-sectional shape of the metal tube. The metal tube is penetrated into the through hole, and both end portions of the metal tube protruding from both ends of the wood are configured as input portions for axial force.
[0014]
The invention described in claim 5 is characterized in that, in the unbonded composite axial force member of wood and metal member described in claim 1, 2 or 4, the outer periphery of the wood and the wooden board is bound by a plurality of bands. To do.
[0015]
The invention described in claim 6 is the unbonded composite axial force member of wood and metal member according to claim 1 or 2, wherein the wooden board is composed of a set of wooden board pieces divided into a plurality in the longitudinal direction of the metal plate. It is characterized by being.
[0016]
The invention described in claim 7 is the unbonded composite axial force member of wood and metal member according to claim 1 or 2, wherein two woods superimposed on both sides of the metal plate are overlapped along the side surface. The reinforcing sheet is sandwiched between the wooden boards.
[0017]
According to an eighth aspect of the present invention, in the unbonded composite axial force member of wood and metal member according to the sixth aspect, among the wooden board pieces, those located at both ends of the member are made of a material having high shear strength such as plywood. It is characterized by being.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, illustrated embodiments of the present invention will be described.
The basics of the unbonded combined axial force member of wood and metal members according to the present invention are formed by synthesizing wood in an unbonded state in an arrangement that prevents buckling of structural metal members such as steel, stainless steel, and aluminum materials. The present invention is preferably implemented with a configuration in which both end portions of the metal member protruding from the end portion of the wood are input portions for axial force (the invention according to claim 1). In other words, the metal member bears the entire load, and the wood is configured to realize the concept of working only as a buckling stiffener.
[0019]
More specifically, first, the unbonded composite axial force member shown in FIGS. 1A to 1C is formed by superimposing woods 2 and 2 made of squares on both the front and back surfaces of the steel plate 1. The wooden plates 3 and 3 are arranged on both sides of the wooden plate 3, and the wooden plates 3 and 3 and the two woods 2 and 2 on both sides of the steel plate 1 are connected to each other by a plurality of nails 4 or the like. Both ends of the steel plate 1 protruding from the end of 2 are configured as input portions 5 and 5 for axial force that connect with other materials (the invention according to claim 2). In short, the steel plate 1 and the two woods 2 and 2 and the wood plates 3 and 3 are not bonded or connected at all. The nail 4 is used only for joining the two timbers 2, 2 and the wooden board 3 stacked on both sides of the steel plate 1, thereby realizing an unbonded state. The wood 2 and the steel plate 1 have an unbonded structure that maintains a combined state in which the relative positions of the two materials do not change (does not shift) due to the action of gravity or vibration only by the frictional force of the surfaces in contact with each other by overlapping, Frictional force is usually small enough not to be a problem. Therefore, this unbonded combined axial force member does not require any other parts such as bolts to be unbonded, and its structure is extremely simple and easy to manufacture.
[0020]
Consider a state in which a compressive force acts on the unbonded combined axial force member to cause bending deformation due to buckling. While the woods 2 and 2 on both sides follow the bending deformation of the steel plate 1, the axial force is almost completely cut off from the steel plate 1, so that the steel plate 1 exerts the full axial force through the input parts 5 and 5. The timber 2 acts purely as a buckling stiffener. Further, considering the case where a tensile force is applied, the steel plate 1 also bears the entire axial force through the input portions 5 and 5. When the wood 2 has a bending rigidity necessary and sufficient to prevent elastic buckling of the steel plate 1, the compression yield strength of the unbonded composite axial force member is equivalent to the tensile strength. Instead of the steel plate 1 (steel material), a metal member generally used as a structural material such as a stainless steel material or an aluminum material can be similarly applied. As the wood 2 and the wood board 3, in addition to normal lumbering, processed materials such as laminated wood can be used.
[0021]
Incidentally, when an example of the specifications such as the size of the unbonded composite axial force member is shown, the steel plate 1 has a thickness of 9 mm, a width dimension of 105 mm, a length of 4300 mm, and a weight of about 30 kg. The timber 2 is a cedar timber having a side length of 105 mm, a length of 4 m, and a weight per one of 22 kg. The wooden board 3 has a thickness of 15 mm, a width dimension of 210 mm, a length of 4 m, and a weight per sheet of about 6 kg. Accordingly, the weight of each component constituting the unbonded combined axial force member is such that an operator can carry it by one person. The total weight of the members is 86 kg. The length corresponding to 150 mm at both ends of the steel plate 1 is used as the input unit 5. The average value of the maximum proof stress of the unbonded composite axial force member of the above specification is 237 KN, the average value of the steel plate compressive stress at the maximum proof stress is 251 MPa, the axial deformation amount at the maximum compression is 5.32 mm, and the out-of-plane The maximum deformation in the direction was about 7.2 mm at the central part. The maximum strength point was reached by splitting fracture of the wood board 3. Therefore, this unbonded composite axial force member can be used, for example, as a pillar, bracing, or truss member of a small building.
[0022]
For comparison, when a square steel pipe is used as the bending buckling stiffener of the steel plate 1 used for the unbonded composite axial force member having the above-described configuration as in the prior art, the required sectional secondary moment of the square steel pipe is about 306 cm. ⁴ or about 67 cm ⁴ are considered. Since each square tube has a weight of about 106 kg and about 86 kg, it is no longer necessary to use heavy machinery for its transportation. The total weight added to the weight of the steel plate 1 (about 30 kg) is 136 kg for the former and 116 kg for the latter. It is apparent that the unbonded composite axial force member of the present invention can achieve a weight reduction of 25% to 36% with respect to the comparative example.
[0023]
Next, the embodiment shown in FIGS.
This unbonded combined axial force member is also common to the embodiment of FIG. 1 up to the point that two timbers 2, 2 manufactured as square members are superimposed on both surfaces of the steel plate 1. However, as a restraining means between the steel plate 1 and the woods 2, 2 on both sides thereof, the difference is that the outer peripheries of the two woods 2, 2 on both sides are bound by a plurality of bands 6. Therefore, the steel plate 1 and the wood 2 are in an unbonded state simply in contact. The point that both ends of the steel plate 1 protruding from the end of the wood 2 are configured as the axial force input portions 5 and 5 is the same (the invention described in claim 3).
[0024]
As the bands 6 described above, a band obtained by bending a well-known metal plate frequently used for packing wood, a band made of resin (including reinforcing fibers), a steel wire or the like is appropriately selected and used. it can. In short, it is sufficient to exhibit a binding force that does not impair the stiffening effect of bending buckling of the steel plate 1 by the wood 2 and to exhibit a considerably long useful life. The number and pitch to be bound by the bands 6 are determined based on the same idea.
[0025]
In addition, as a variation of the configuration in which the steel plate 1 and the wood 2 are restrained in an unbonded state with a band, in the embodiment including the wood plate 3 of FIG. (Invention described in claim 5).
[0026]
Next, the embodiment shown in FIGS. 3A and 3B shows an example in which measures for preventing shear fracture of the wooden board 3 are taken for the unbonded combined axial force member of FIG. That is, when a compressive force acts on the unbonded combined axial force member of FIG. 1 and bending deformation occurs due to buckling, the wooden board 3 bears a shearing force accompanying bending. Since the shear strength of the wood board 3 is inherently very low, the wood board 3 was destroyed in advance (test results showed that the maximum proof stress was reached, and splitting occurred in the axial direction from the center of both ends of the wood board 3). There was concern that the strength of the force member could be reduced.
[0027]
As an alternative, in the embodiment of FIG. 3, the wooden board is constituted by a set of a plurality of wooden board pieces 3 ′ divided (divided) into a plurality in the longitudinal direction of the steel sheet 1 (in the direction perpendicular to the wood axis of the wooden board) ( Invention of Claim 6).
The intention is that, as shown in FIG. 3B, when a buckling occurs due to a compressive force acting on the steel sheet 1, the bending of the steel sheet is not caused without burdening each wooden board piece 3 'with a large shear stress. In order to prevent a shear failure of at least the wood board piece 3 ′ by causing a corresponding shift between the joining edges of the adjacent wood board pieces 3 ′. Thus, in the case of a configuration in which the wooden board is divided into small pieces, the wooden board piece 3 ′ itself may be of a small size, and an inexpensive wooden material such as a small-diameter wood or a half-end piece can be used effectively, and the splitting is performed. There is also an advantage that cost reduction can be achieved at the same time as preventing a decrease in yield strength. Connecting each wood board piece 3 'to the wood 2 with a plurality of nails 4 is the same as in FIG.
In the case of the embodiment of FIG. 3, each wood board piece 3 ′ can use the strength of the wood board more effectively by using the wood fiber streak in a direction orthogonal to the axial direction of the steel sheet 1. Or if it uses what was manufactured with the material with high shear strength, such as a plywood, for the wooden board piece 3a 'and 3a' located at both ends of a member, it will become a synthetic material with higher strength and reliability (invention described in claim 8). .
[0028]
FIG. 4 shows an embodiment in which the length of the wood board piece 3 ′ is slightly increased to reduce the number of divisions, and a material having high shear strength such as plywood is used for the wood board piece 3a ′ at both ends of the member. This is because it is convenient to reduce the man-hours for producing the unbonded composite axial force member.
[0029]
Next, in the embodiment shown in FIG. 5, similarly to the embodiment of FIG. 1, two timbers 2, 2 manufactured as square members are overlapped on both surfaces of the steel plate 1, and the two timbers 2, 2 are overlapped. A wood board 3 is arranged along the side surface, and the wood board 3 and the two woods 2 and 2 are connected by a nail 4. However, the reinforcing sheet 7 is sandwiched between the two timbers 2, 2 superimposed on both surfaces of the steel plate 1 and the wooden board 3 stacked along the side surface (claim 7). Described invention). This is an embodiment in which the reinforcing sheet 7 has an effect of preventing shear fracture of the wooden board 3.
As the reinforcing sheet 7, for example, a film material containing glass fiber can be suitably used.
[0030]
Next, the unbonded composite axial force member shown in FIG. 6 has almost the same shape as the cross-sectional shape of the metal pipe 11 such as a steel pipe or an aluminum pipe in the axial direction of the center portion of the wood 12 using so-called logs. A large through hole through which the metal tube 11 can pass is provided, the metal tube 11 is penetrated through the through hole, and both ends of the metal tube 11 protruding from both ends of the wood 12 are input of axial force. It is comprised as the part 15 (Invention described in Claim 4).
It is sufficient that the metal tube 11 is manufactured to such an extent that it makes light contact with the log wood 12 over the entire length. In the case of the present embodiment, the log wood 12 is originally an integral structure, so it is sufficient to simply penetrate the metal tube 11, and the manufacture is extremely easy. The log wood 12 can be sufficiently expected to function as a buckling stiffener for the metal tube 11.
[0031]
The unbonded combined axial force member of FIG. 7 shows an example of a configuration in which the outer periphery of the wood 12 of FIG. 6 is further bound and reinforced by a plurality of bands 6. The binding by the bands 6 has an effect of preventing the buckling stiffening effect from being lowered due to the initial cracking of the log wood 12.
[0032]
[Effects of the present invention]
The unbonded composite axial force member of wood and metal members according to the inventions described in claims 1 to 8 is clearly separated in the mechanical functions of the wood and the metal material, the metal material bears the entire load, and the wood is the metal material Therefore, the reliability of the strength of each member is high, and a rational and economical design is possible.
In addition to being light in weight as wood is used, it exhibits high specific strength as a member, and the weight of each component can be carried by an operator alone, eliminating the need for heavy machinery, excellent workability, and construction cost Can be reduced.
In addition, the structure is simple, it can be manufactured at low cost, and it has excellent load bearing performance and stability against axial force. And there is no problem caused by the difference in thermal expansion between wood and metal, and it is economical and highly reliable.
[Brief description of the drawings]
1A, 1B and 1C are a front view, a plan view, and an enlarged vertical sectional view showing an embodiment of an unbonded combined axial force member according to the present invention.
FIGS. 2A, 2B, and 2C are a front view, a plan view, and an enlarged vertical sectional view showing different embodiments of an unbonded combined axial force member according to the present invention.
FIGS. 3A and 3B are a front view showing different embodiments of an unbonded combined axial force member according to the present invention and an explanatory diagram conceptually showing a bending buckling state thereof. FIGS.
FIG. 4 is a front view showing still another embodiment of the unbonded combined axial force member according to the present invention.
FIGS. 5A and 5B are a front view and a plan view showing different embodiments of an unbonded combined axial force member according to the present invention. FIGS.
FIGS. 6A and 6B are a front view and an enlarged longitudinal sectional view showing different embodiments of an unbonded combined axial force member according to the present invention. FIGS.
FIGS. 7A and 7B are a front view and an enlarged vertical sectional view showing still another embodiment of an unbonded combined axial force member according to the present invention. FIGS.
[Explanation of symbols]
1 Steel plate (metal member)
2 Wood 3 Wood board 4 Nail 5 Input part 6 Bands 3 'Wood board piece 7 Reinforcement sheet 3a' Wood board piece

Claims (8)

It is characterized in that wood is synthesized in an unbonded state in an arrangement for preventing buckling of the metal member, and both ends of the metal member protruding from the end of the wood are configured as input portions for axial force. , Unbonded composite axial force member of wood and metal parts. Wood is overlapped on both sides of the metal plate, a wooden plate is placed along the side surfaces of the two woods on both sides, and the wooden plate and the two woods on both sides of the metal plate are connected with nails or the like, respectively. An unbonded composite axial force member made of wood and a metal member, wherein both end portions of the metal plate protruding from the base plate are configured as input portions for axial force. Wood is superimposed on both sides of the metal plate, and the two woods on both sides are formed by bundling the outer periphery with a plurality of bands, and both ends of the metal plate protruding from the end of the wood serve as input portions for axial force An unbonded composite axial force member made of wood and a metal member, characterized in that it is configured. The wood has a through hole that is almost the same size and the same size as the cross section of the metal tube, and the metal tube can pass through the metal tube. The metal tube penetrates the through hole and protrudes from both ends of the wood. An unbonded composite axial force member made of wood and a metal member, wherein both end portions of the metal tube are configured as input portions for axial force. 5. The unbonded combined axial force member of wood and metal members according to claim 1, wherein the outer periphery of the wood and the wooden board is bound by a plurality of bands. 3. The unbonded combined axial force member of wood and metal member according to claim 1 or 2, wherein the wood plate is composed of a set of wood plate pieces divided into a plurality of pieces in the longitudinal direction of the metal plate. The wood and metal according to claim 1 or 2, wherein a reinforcing sheet is sandwiched between two pieces of wood superimposed on both sides of the metal plate and a wood plate stacked along the side surface thereof. Unbonded composite axial force member. 7. The unbonded composite axial force member of wood and metal members according to claim 6, wherein the wood plate pieces located at both ends of the member are made of a material having high shear strength such as plywood.

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