Pre-stressed wooden structure and method for manufacturing the same

Abstract

To provide a pre-stressed wooden structure which facilitates formation of a groove tension steel wire insertion groove inserted into a tension steel wire in a swan board, and makes structural weak points as little as possible.SOLUTION: A method for manufacturing a pre-stressed wooden structure includes the steps of: forming a plurality of swan boards 30 so that a fiber direction is a longitudinal direction; forming a tension steel wire insertion groove 20 over a full length of a joined surface of the swan board 30, and forming projection parts 21 projecting from both walls at a position to be as a node of buckling deformation of the tension steel wire insertion groove 20; joining the swan board 30 where the tension steel wire insertion groove 20 is formed and the swan board 30 where the tension steel wire insertion groove is not formed, and constituting a wooden structure 29; and inserting a tension steel wire 28 of a pre-stressing device 36 into the tension steel wire insertion groove 20, tensioning the tension steel wire 28, thereby applying axial compressive stress onto the wooden structure 29, and fixing both of the ends of the tension steel wire 28 to a fixing device 32 at both ends of the wooden structure 29.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a prestressed wooden structure that prevents buckling of wooden structures such as glued laminated timber, CLT (cross-laminated timber), LVL (laminated veneer lumber), beams, columns, and flat panels, and a method for manufacturing the same.

Background Art

[0002] The applicant of the present application has proposed a long structure 10 provided with prestress as shown in FIG. 11 (Patent Document 1). This long structure 10 is composed of connecting those with a length within three buckling lengths, axially drilling a through hole 11, forming a fitting recess 19 on the connecting surface of the long structure 10 in this through hole 11, arranging a tension member position holding piece 18, drilling a circular hole 18a having substantially the same diameter as the tension member 12 in this tension member position holding piece 18, passing the tension member 12 through the through hole 11 and the circular hole 18a of the tension member position holding piece 18, and applying prestress through a fixing device 14 via plates 13 at both ends so as to obtain a predetermined compressive force. With such a configuration, the long structure 10 connected in three is prevented from bending due to buckling.

[0003] Further, in Patent Document 1, when one long structure has a length equal to or greater than the buckling length, an example is shown in which a fitting hole is drilled from the side at a position of the buckling length in the middle thereof, a tension member position holding piece is fitted, and a tension member is inserted.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the long structural body 10 described in Patent Document 1, since the tension member position retaining pieces 18 must be arranged for each joint surface of the long structural body 10 formed by connecting a plurality of pieces divided within the buckling length, the structure becomes somewhat complicated, and it is somewhat troublesome to form the fitting recesses 19 for arranging the tension member position retaining pieces 18. Moreover, since the fitting recesses 19 are orthogonal to the axis (longitudinal) direction of the long structural body 10, there is a problem of becoming a structural weakness. Also, when the member length of a single long structural body is equal to or greater than the buckling length, a fitting hole is drilled from the side in the middle, the tension member position retaining piece is fitted, and the tension member is inserted. Therefore, there is a problem that the position of the fitting hole drilled from the side becomes a structural weakness of the long structural body.

[0006] The present invention has been made to solve the above problems. By making use of the characteristics of the wooden structure, an insertion groove for setting a tension steel wire is formed at the stage of a single veneer or a veneer block composed of a plurality of veneers before laminating as a wooden structure, and this member is laminated and adhered together with the veneer without the insertion groove formed to form a wooden structure and prestress is applied.

Means for Solving the Problems

[0007] The method for manufacturing a prestressed wooden structure according to claim 1 is a veneer forming step of forming a plurality of veneers 30 with the fiber direction in the longitudinal direction, a tension steel wire insertion groove forming step of forming a tension steel wire insertion groove 20 over the entire length on the joint surface of the one veneer 30 with the other veneer 30, and forming protrusions 21 protruding from both walls at the position where it is desired to be a node of buckling deformation of the tension steel wire insertion groove 20, a wooden structure constituting step of joining the one veneer 30 in which the tension steel wire insertion groove 20 is formed and the other veneer 30 in which the tension steel wire insertion groove 20 is not formed to constitute a wooden structure 29, Insert the tensioned steel wire 28 of the prestressing device 36 into the tensioned steel wire insertion groove 20, and tension this tensioned steel wire 28 with a jack or the like to apply an axial compressive stress to the wooden structure 29. Fix both ends of this tensioned steel wire 28 at both ends of the wooden structure 29 with a fixing device 32. Axial compressive force applying step and It is characterized by comprising.

[0008] When the wooden structure is composed of the planar member 35, the manufacturing method of the prestressed wooden structure is as follows. A veneer forming step of forming a plurality of veneers 30 whose fiber direction is the longitudinal direction; A planar member forming step of joining the plurality of veneers 30 whose fiber directions intersect each other to form a planar member 35; A tensioned steel wire insertion groove forming step of forming a tensioned steel wire insertion groove 20 over the entire length on the joint surface of the one veneer 30 forming the planar member 35 with the other veneer 30, and forming protruding portions 21 protruding from both walls at positions where buckling deformation nodes of the tensioned steel wire insertion groove 20 are desired; A wooden structure forming step of joining the one veneer 30 in which the tensioned steel wire insertion groove 20 is formed and the other veneer 30 in which the tensioned steel wire insertion groove 20 is not formed to form a planar wooden structure 29; Insert the tensioned steel wire 28 of the prestressing device 36 into the tensioned steel wire insertion groove 20, and tension this tensioned steel wire 28 with a jack or the like to apply an axial compressive stress to the wooden structure 29. Fix both ends of this tensioned steel wire 28 at both ends of the wooden structure 29 with a fixing device 32. Axial compressive force applying step and It is characterized by comprising.

[0009] When the wooden structure is composed of the column member 34, the manufacturing method of the prestressed wooden structure is as follows. A veneer forming step of forming a plurality of veneers 30 whose fiber direction is the longitudinal direction; A column member forming step of joining the plurality of veneers 30 to form a column member 34; In at least two joint surfaces of the other draw plate 30 in the one draw plate 30 forming the column member 34, a tension steel wire insertion groove 20 is formed over the entire length, and a protrusion 21 protruding from both walls at a position where buckling deformation nodes of the tension steel wire insertion groove 20 are desired is formed in a tension steel wire insertion groove forming step. A wooden structure constituting step of joining the one column member 34 in which the tension steel wire insertion groove 20 is formed and the other column member 34 in which the tension steel wire insertion groove 20 is not formed to form a columnar wooden structure 29. An axial compressive force applying step of inserting the tension steel wire 28 of the prestressing device 36 into the tension steel wire insertion groove 20 and tensioning the tension steel wire 28 to apply an axial compressive stress to the wooden structure 29, and fixing both ends of the tension steel wire 28 with a fixing device 32 at both ends of the wooden structure 29. It is characterized by comprising the above.

[0010] In order to prevent buckling in the width direction of the wooden structure 29, the protrusion 21 is formed to protrude in the width direction of the draw plate 30 from both walls at a position where buckling deformation nodes of the tension steel wire insertion groove 20 are desired.

[0011] In order to prevent buckling in a direction orthogonal to the width direction of the wooden structure 29, the protrusion 21 is formed to protrude in a direction orthogonal to the width direction of the draw plate 30 from both walls at a position where buckling deformation nodes of the tension steel wire insertion groove 20 are desired.

[0012] The prestressed wooden structure of the present invention In a wooden structure 29 formed by joining a plurality of draw plates 30 whose fiber direction is the longitudinal direction A tension steel wire insertion groove 20 is formed over the entire length on the joint surface of the one pulling plate 30 with the other pulling plate 30, and protrusions 21 protruding from both walls at a position where buckling deformation nodes are desired in the middle of the tension steel wire insertion groove 20 are formed. The wooden structure 29 is composed of a plurality of joined pulling plates 30 with the tension steel wire insertion groove 20 and protrusions 21 formed and pulling plates 30 without them. The tension steel wire 28 of the prestressing device 36 is inserted into the tension steel wire insertion groove 20 to tension this tension steel wire 28, thereby applying axial compressive stress to the wooden structure 29. Both ends of this tension steel wire 28 are fixed by a fixing device 32 at both ends of the wooden structure 29, and the tension steel wire 28 is characterized in that an axial compressive force is applied to the wooden structure 29 so as to be in contact with the weak axis direction of the protrusion 21.

[0013] The prestressed wooden structure made of the planar member of the present invention is a wooden structure 29 formed by joining two or more planar members 35 formed by joining a plurality of pulling plates 30 whose fiber directions are orthogonal to each other in the planar direction. A tension steel wire insertion groove 20 is formed over the entire length on the joint surface of any one of the joined planar members 35, and protrusions 21 protruding from both walls at a position where buckling deformation nodes are desired in the tension steel wire insertion groove 20 are formed. The planar member 35 with the tension steel wire insertion groove 20 and protrusions 21 formed and the planar member 35 without them are joined to form a planar wooden structure 29. The tension steel wire 28 of the prestressing device 36 is inserted into the tension steel wire insertion groove 20 and this tension steel wire 28 is tensioned with a jack or the like to apply axial compressive stress to the wooden structure 29, and both ends of this tension steel wire 28 are fixed by a fixing device 32 at both ends of the wooden structure 29.

[0014] The prestressed wooden structure made of the column member of the present invention is A wooden structure 29 is formed by joining a plurality of draw plates 30 with the fiber direction in the longitudinal direction to form a column member 34. In one of the draw plates 30 forming the column member 34, tension steel wire insertion grooves 20 are formed over the entire length at at least two joint surfaces of the other draw plates 30. Protrusions 21 protruding from both walls at a position where buckling deformation nodes of the tension steel wire insertion grooves 20 are desired are formed. One of the protrusions 21 is formed by protruding in the width direction of the draw plate 30 from both walls at a position where buckling deformation nodes of the tension steel wire insertion grooves 20 are desired. The other protrusion 21 is formed by protruding in a direction orthogonal to the width direction of the draw plate 30 from both walls at a position where buckling deformation nodes of the tension steel wire insertion grooves 20 are desired. The draw plate 30 with the tension steel wire insertion grooves 20 and protrusions 21 formed and the draw plate 30 without them are joined to form a columnar wooden structure 29. The tension steel wire 28 of a prestressing device 36 is inserted into the tension steel wire insertion grooves 20, and this tension steel wire 28 is tensioned by a jack or the like to apply axial compressive stress to the wooden structure 29. Both ends of this tension steel wire 28 are fixed by a fixing device 32 at both ends of the wooden structure 29.

Effect of the Invention

[0015] According to the invention described in claim 1, the method for manufacturing a prestressed long wooden structure is as follows. A draw plate forming step of forming a plurality of draw plates with the fiber direction in the longitudinal direction. A tension steel wire insertion groove forming step of forming tension steel wire insertion grooves over the entire length at the joint surfaces of one of the draw plates with the other draw plates, and forming protrusions protruding from both walls at a position where buckling deformation nodes of the tension steel wire insertion grooves are desired. A wooden structure forming step of joining the one draw plate with the tension steel wire insertion grooves formed and the other draw plate without the tension steel wire insertion grooves formed to form a wooden structure. An axial compressive force applying step of inserting the tension steel wire of a prestressing device into the tension steel wire insertion grooves and tensioning this tension steel wire to apply axial compressive stress to the wooden structure, and fixing both ends of this tension steel wire by a fixing device at both ends of the wooden structure. Since it is composed of [the following components], there is no need to arrange tension member position retaining members as in the prior art, which simplifies the structure. Also, there is no need to form fitting recesses for arranging tension member position retaining members, and the intersecting fitting recesses do not become structural weaknesses. In addition, there is no need to excavate fitting holes from the side in the middle of the long structural body, and it does not become a structural weakness of the wooden structural body. Moreover, the working process is easy.

[0016] According to the invention described in claim 2, A veneer forming step of forming a plurality of veneers with the fiber direction in the longitudinal direction, A planar member forming step of joining the plurality of veneers with intersecting fiber directions to form a planar member, A tension steel wire insertion groove forming step of forming a tension steel wire insertion groove extending over the entire length on the joint surface of one veneer forming the planar member with the other veneer, and forming protrusions protruding from both walls at positions where it is desired to be the nodes of buckling deformation of the tension steel wire insertion groove, A wooden structural body constituting step of joining the one veneer in which the tension steel wire insertion groove is formed and the other veneer in which the tension steel wire insertion groove is not formed to constitute a planar wooden structural body, An axial compression force applying step of inserting a tension steel wire of a prestressing device into the tension steel wire insertion groove and tensioning this tension steel wire to apply an axial compression stress to the wooden structural body, and fixing both ends of this tension steel wire at both ends of the wooden structural body by a fixing device Since it consists of [the above steps], the present invention can be used when forming a planar member.

[0017] According to the invention described in claim 3, A veneer forming step of forming a plurality of veneers with the fiber direction in the longitudinal direction, A column member forming step of joining a plurality of the veneers to form a column member, A tension steel wire insertion groove forming step of forming a tension steel wire insertion groove extending over the entire length on at least two joint surfaces of the other veneer in one veneer forming the column member, and forming protrusions protruding from both walls at positions where it is desired to be the nodes of buckling deformation of the tension steel wire insertion groove, A wooden structure forming step of joining the one column member having the tension steel wire insertion groove formed therein and the other column member not having the tension steel wire insertion groove formed therein to form a columnar wooden structure; An axial compressive force applying step of inserting a tension steel wire of a prestressing device into the tension steel wire insertion groove and tensioning the tension steel wire to apply an axial compressive stress to the wooden structure, and fixing both ends of the tension steel wire with a fixing device at both ends of the wooden structure; Since it consists of the above, the present invention can be used when forming a column member.

[0018] According to the invention described in claim 4, Since the protrusion is formed to protrude in the width direction of the pulling plate from both walls at the position where it is desired to be a buckling deformation node of the tension steel wire insertion groove, it is effective when buckling occurs in the width direction of the wooden structure.

[0019] According to the invention described in claim 5, Since the protrusion is formed to protrude in a direction orthogonal to the width direction of the pulling plate from both walls at the position where it is desired to be a buckling deformation node of the tension steel wire insertion groove, it is effective when buckling occurs in a direction orthogonal to the width direction of the wooden structure.

[0020] According to the invention described in claim 6, In a wooden structure formed by joining a plurality of pulling plates having a fiber direction in the longitudinal direction, A tension steel wire insertion groove is formed over the entire length on the joint surface of the one pulling plate with the other pulling plate, and protrusions protruding from both walls at the position where it is desired to be a buckling deformation node in the middle of the tension steel wire insertion groove are formed. The wooden structure is composed of a plurality of the pulling plates having the tension steel wire insertion groove and the protrusions and the pulling plates not having the tension steel wire insertion groove and the protrusions joined together. An axial compressive stress is applied to the wooden structure by inserting a tension steel wire of a prestressing device into the tension steel wire insertion groove and tensioning the tension steel wire, and both ends of the tension steel wire are fixed with a fixing device at both ends of the wooden structure. An axial compressive force is applied to the wooden structure so as to be in contact with the tension steel wire in the weak axis direction of the protrusion. Since it consists of the above, it has the same effect as in claim 1.

[0021] According to the invention described in claim 7, a wooden structure formed by joining two or more planar members formed by joining a plurality of veneer boards whose fiber directions are orthogonal to each other in the planar direction, wherein a tension steel wire insertion groove is formed over the entire length on the joint surface of any one of the planar members to be joined, and protrusions protruding from both walls at a position where buckling deformation nodes of the tension steel wire insertion groove are desired are formed, and the planar member having the tension steel wire insertion groove and the protrusions and the planar member not having the tension steel wire insertion groove and the protrusions are joined to form a planar wooden structure, and the tension steel wire of the prestressing device is inserted into the tension steel wire insertion groove to tension the tension steel wire, thereby applying axial compressive stress to the wooden structure, and both ends of the tension steel wire are fixed by a fixing device at both ends of the wooden structure. Therefore, it has the same effect as that of claim 2.

[0022] According to the invention described in claim 8, a wooden structure formed by joining a plurality of veneer boards whose fiber directions are in the longitudinal direction to form a column member, wherein tension steel wire insertion grooves are formed over the entire length on at least two joint surfaces of the other veneer board in the one veneer board forming the column member, and protrusions protruding from both walls at a position where buckling deformation nodes of the tension steel wire insertion groove are desired are formed, one of the protrusions is formed by protruding in the width direction of the veneer board from both walls at a position where buckling deformation nodes of the tension steel wire insertion groove are desired, the other protrusion is formed by protruding in a direction orthogonal to the width direction of the veneer board from both walls at a position where buckling deformation nodes of the tension steel wire insertion groove are desired, the veneer board having the tension steel wire insertion groove and the protrusions and the veneer board not having the tension steel wire insertion groove and the protrusions are joined to form a columnar wooden structure, and the tension steel wire of the prestressing device is inserted into the tension steel wire insertion groove to tension the tension steel wire, thereby applying axial compressive stress to the wooden structure, and both ends of the tension steel wire are fixed by a fixing device at both ends of the wooden structure. Therefore, it has the same effect as that of claim 3.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0024] The prestressed long wooden structure of the present invention is A process of forming a drawing board 30 with the fiber direction being the longitudinal direction, A process of forming a tension steel wire insertion groove 20 over the entire length on the joint surface of the drawing board 30 with other drawing boards 30, and forming protrusions 21 protruding from both walls at the buckling occurrence positions of the tension steel wire insertion groove 20, A process of forming a wooden structure 29 by joining the drawing board 30 with the tension steel wire insertion groove 20 formed and the drawing board 30 without the groove, A process of inserting the tension steel wire 28 of the prestressing device 36 into the tension steel wire insertion groove 20 and fixing the tension steel wire 28 at both ends of the wooden structure 29 by a fixing device 32, A process of applying an axial compressive force to the wooden structure 29 in contact with the protrusions 21 in the weak axis direction on the fixed tension steel wire 28, which consists of the above steps.

[0025] The prestressed long wooden structure composed of the planar member 35 of the present invention, includes a process of forming a drawing board 30 with the fiber direction being the longitudinal direction, a process of forming a planar member 35 by joining drawing boards 30 with fiber directions intersecting each other, a process of forming a tension steel wire insertion groove 20 over the entire length on the joint surface of the planar member 35 with other members, and forming protrusions 21 protruding from both walls at the buckling occurrence positions of the tension steel wire insertion groove 20, a process of forming a planar wooden structure 29 by joining the planar member 35 with the tension steel wire insertion groove 20 formed and other members without the groove, a process of inserting the tension steel wire 28 of the prestressing device 36 into the tension steel wire insertion groove 20 and fixing the tension steel wire 28 at both ends of the wooden structure 29 by a fixing device 32, a process of applying an axial compressive force to the wooden structure 29 in contact with the protrusions 21 in the weak axis direction on the fixed tension steel wire 28, which consists of the above steps.

[0026] The prestressed long wooden structure composed of the column member 34 of the present invention a veneer forming step of forming a veneer 30 whose fiber direction is the longitudinal direction; a column member forming step of joining a plurality of the veneers 30 to form a column member 34; a tension steel wire insertion groove forming step of forming tension steel wire insertion grooves 20 extending over the entire length at at least two joint surfaces of the column member 34 with other members, and forming protrusions 21 protruding from both walls at the buckling occurrence positions of the tension steel wire insertion grooves 20; a wooden structure constituting step of joining the column member 34 in which the tension steel wire insertion grooves 20 are formed and the column member 34 in which the tension steel wire insertion grooves 20 are not formed to constitute a columnar wooden structure 29; a tension steel wire fixing step of inserting the tension steel wire 28 of a prestressing device 36 into the tension steel wire insertion grooves 20 and fixing the tension steel wire 28 with a fixing device 32 at both ends of the wooden structure 29; an axial compressive force applying step of applying an axial compressive force to the wooden structure 29 in contact with the protrusions 21 in the weak axis direction to the fixed tension steel wire 28 and comprises.

[0027] In order to be used when buckling occurs in the width direction of the wooden structure 19, the protrusions 21 are formed to protrude in the width direction of the veneer 30 from both walls at the buckling occurrence positions of the tension steel wire insertion grooves 20.

[0028] In order to be used when buckling occurs in a direction orthogonal to the width direction of the wooden structure 19, the protrusions 21 are formed to protrude in a direction orthogonal to the width direction of the veneer 30 from both walls at the buckling occurrence positions of the tension steel wire insertion grooves 20.

[0029] In the wooden structure 29 in which a plurality of veneers 30 whose fiber direction is the longitudinal direction are joined, A tension steel wire insertion groove 20 is formed over the entire length of the joint surface of the draw plate 30, and protrusions 21 protruding from both walls of the buckling occurrence location in the middle of the tension steel wire insertion groove 20 are formed. The wooden structure 29 is composed of a plurality of draw plates 30 with the tension steel wire insertion groove 20 and protrusions 21 formed and draw plates 30 without them joined together. The tension steel wire 28 of the prestressing device 36 is inserted into the tension steel wire insertion groove 20, and this tension steel wire 28 is fixed by a fixing device 32 at both ends of the wooden structure 29. The tension steel wire 28 is provided with an axial compressive force on the wooden structure 29 so as to be in contact with the protrusions 21 in the weak axis direction.

[0030] A wooden structure 29 formed by joining two or more planar members 35 formed by joining draw plates 30 with fiber directions orthogonal to each other in the planar direction. A tension steel wire insertion groove 20 is formed over the entire length of the joint surface of any one of the joined planar members 35, and protrusions 21 protruding from both walls of the buckling occurrence position of the tension steel wire insertion groove 20 are formed. The planar member 35 with the tension steel wire insertion groove 20 and protrusions 21 formed and the planar member 35 without them are joined together to form a planar wooden structure 29. The tension steel wire 28 of the prestressing device 36 is inserted into the tension steel wire insertion groove 20, and this tension steel wire 28 is fixed by a fixing device 32 at both ends of the wooden structure 29. The fixed tension steel wire 28 is provided with an axial compressive force on the wooden structure 29 in contact with the protrusions 21 in the weak axis direction.

[0031] A wooden structure 29 is formed by joining a plurality of draw plates 30 with the fiber direction being the longitudinal direction to form a column member 34. Tension steel wire insertion grooves 20 are formed over the entire length on at least two joint surfaces of the draw plate 30 with other draw plates 30. Protrusions 21 protruding from both walls at the buckling occurrence positions of the tension steel wire insertion grooves 20 are formed. One of the protrusions 21 is formed by protruding from both walls at the buckling occurrence positions of the tension steel wire insertion grooves 20 in the width direction of the draw plate 30. The other protrusion 21 is formed by protruding from both walls at the buckling occurrence positions of the tension steel wire insertion grooves 20 in a direction orthogonal to the width direction of the draw plate 30. The draw plates 30 with the tension steel wire insertion grooves 20 and the protrusions 21 are joined to the draw plates 30 without them to form a columnar wooden structure 29. The tension steel wire 28 of the prestressing device 36 is inserted into the tension steel wire insertion grooves 20, and this tension steel wire 28 is fixed at both ends of the wooden structure 29 by fixing devices 32. The fixed tension steel wire 28 applies an axial compressive force to the wooden structure 29 in contact with the protrusions 21 in the weak axis direction.

Example

[0032] Hereinafter, Example 1 of the present invention will be described with reference to FIGS. 1 to 4. FIGS. 1 and 2 show the long wooden structure 29 of the present invention. This wooden structure 29 shows an example in which prestress is applied to an LVL type 26 type structural beam material formed by laminating draw plates 30 so that the (fiber) grain is in the same direction. The side view is shown in FIG. 3(a). This long wooden structure 29 takes, for example, a beam member 37 with a width of 220 mm, a thickness of 570 mm, and a length of 10 to 15 m as an example. The thickness of the draw plates 30 to be laminated is about 20 to 50 mm. Not only is it laminated in the thickness direction, but also the ends are cut in a V shape or the like and connected in the length direction as required.

[0033] As shown in FIGS. 1 and 2, a prestressing steel wire insertion groove 20 through which the tension steel wire 28 of the prestressing device 36 is inserted is formed in the pulling plate 30 before lamination. This prestressing steel wire insertion groove 20 has, for example, a width of 40 mm and a depth of 20 mm. In the middle of this prestressing steel wire insertion groove 20, protrusions 21 that project inward (in the width direction) from both side wall surfaces and oppose each other are formed. These protrusions 21 are formed in a mountain shape by a tension steel material contact surface 23 and an inclined surface 22, and there is a gap 33 through which the tension steel wire 28 can pass between the opposing tension steel material contact surfaces 23. The lengths of the tension steel material contact surface 23 and the inclined surface 22 are about 30 to 50 mm, and these protrusions 21 are formed at one to a plurality of positions according to the buckling length of the wooden structure 29. When the diameter of the tension steel wire 28 made of PC steel wire or the like is 17.8 mm, the width of the gap 33 is about 18 to 20 mm, which is slightly wider than the diameter of the tension steel wire 28. The inclined surface 22 is formed as gently as possible so as not to become a structural weakness when the wooden structure 29 bends.

[0034] More specifically, when the thickness of the pulling plate 30 is 40 mm, the prestressing steel wire insertion groove 20 has a depth of 20 mm and a width of about 30 to 40 mm, and as shown in FIG. 2, protrusions 21 are formed at the bending positions of the wooden structure 29 in the prestressing steel wire insertion groove 20. In the embodiments shown in FIGS. 1 and 2, the protrusion 21 is composed of a linear tension steel material contact surface 23 and an inclined surface 22, but it is not limited to this example. As shown in FIG. 4(a), it may be formed in an arc shape without a boundary between the tension steel material contact surface 23 and the inclined surface 22. Also, as shown in FIG. 4(b), the tension steel material contact surfaces 23 of the opposing protrusions 21 may be formed with a shift of a predetermined distance B. It is desirable that this distance B is not too large.

[0035] As described above, the pulling plates 30 in which the prestressing steel wire insertion grooves 20 are formed and the pulling plates 30 in which the prestressing steel wire insertion grooves 20 are not formed are sequentially laminated and joined as shown in FIGS. 3(a) and 3(b). After the laminated bonding is completed, the tension steel wire 28 of the prestressing device 36 is inserted into the gap 33 between the opposing protrusions 21 in the tension steel wire insertion groove 20, and both ends of the tension steel wire 28 are made to protrude from both sides of the draw plate 30. The laminated position of the draw plate 30 forming the tension steel wire insertion groove 20 is set at the central position in the width direction of the wooden structure 29, but it may also be approximately at the center in the thickness direction or at a slightly offset position in the vertical direction. A plate 31 and a fixing device 32 are fitted onto the tension steel wire 28 protruding from both ends, and a predetermined load is applied to apply prestress to the wooden structure 29. Then, when the introduced prestress force exceeds the buckling load of the wooden structure 29, the wooden structure 29 attempts to buckle. However, as shown in FIG. 1, the tension steel wire 28 is in close contact with the tension steel material contact surface 23 on the weak axis side that attempts to buckle within the gap 33, and further bending deformation is suppressed, resulting in a long wooden structure 29 that does not buckle and warping is prevented.

Example

[0036] In Example 1 of FIGS. 1 to 4, the wooden structure 29 is exemplified by a beam member 37 having a width of 220 mm, a thickness of 570 mm, and a length of 10 to 15 m. Therefore, buckling is likely to occur in the thin width direction. In Example 2, an example of joining planar members 35 as shown in FIGS. 5 and 6 will be described. As shown in FIG. 5, it can also be applied to a wooden structure 29 composed of planar members 35 laminated and bonded so that the fiber directions of the draw plates 30 are orthogonal to each other. Note that in FIG. 5, since the lengths in the X and Y directions are short compared to the thickness in the Z direction for the purpose of explaining the drawing, it is shown as a member where buckling does not occur. However, when the lengths in the X and Y directions are sufficiently long and there is a possibility of buckling, the present invention is applied. In FIG. 5, tension steel wire insertion grooves 20 and protrusions 21 are formed in the draw plates 30 in the X direction and the draw plates 30 in the Y direction, respectively, before lamination. The tension steel wire 28 of the prestressing device 36 is inserted into these tension steel wire insertion grooves 20 and protrusions 21, respectively, and both ends of the tension steel wire 28 are made to protrude from both sides of the draw plate 30. A plate 31 and a fixing device 32 are fitted onto the tensioned steel wires 28 protruding from both ends of the tensioned steel wire insertion groove 20, and a predetermined load is applied to prestress the wooden structure 29. Then, the wooden structure 29 made of the planar member 35 becomes a long wooden structure 29 that will not buckle in either the X direction or the Y direction when prestressed, and warping is prevented.

[0037] FIG. 6 shows an example in which two planar members 35 similar to those in FIG. 5 are joined. A tensioned steel wire insertion groove 20 is formed over the entire length of the joint surface of the planar member 35 with the other planar member 35, and protrusions 21 protruding from both walls at the buckling occurrence position of the tensioned steel wire insertion groove 20 are formed. The planar member 35 in which the tensioned steel wire insertion groove 20 is formed and the other planar member 35 in which it is not formed are joined to form a planar wooden structure 29. The tensioned steel wire 28 of the prestressing device 36 is inserted into the tensioned steel wire insertion groove 20, and this tensioned steel wire 28 is tensioned with a jack or the like to apply axial compressive stress to the wooden structure 29, and both ends of this tensioned steel wire 28 are fixed by a fixing device 32 at both ends of the wooden structure 29. In this way, a wooden structure 29 made of a planar member 35 that does not buckle is obtained. Note that although FIG. 6 shows a short description of the joint surface where the tensioned steel wire insertion groove 20 is formed, it has a great effect on those with a length where buckling may occur.

Example

[0038] FIGS. 7 and 8 show examples in which the present invention is applied to column members 34 having substantially the same longitudinal and transverse thicknesses. In FIG. 8, when the column member 34 has substantially the same longitudinal and transverse thicknesses, it is unclear whether the direction in which buckling occurs is the X direction or the Y direction in the figure. Therefore, for example, the protrusion 21 (upper side in the figure) of one of the tensioned steel wire insertion grooves 20X for the X axis is formed to protrude in the width direction of the pulling plate 30 from both walls at the buckling occurrence position so that prestress acts in the X direction (lateral direction). In addition, the protrusion 21 (lower side in the figure) of the other tension steel wire insertion groove 20Y for the Y-axis is formed so that prestress acts in the Y direction (vertical direction). By adopting such a configuration, it is possible to configure the structure to function against buckling in both the X and Y directions.

[0039] FIG. 7 shows an example in which the left column member 34a and the right column member 34b are joined to form a column member 34 having substantially the same thickness in both the vertical and horizontal directions, and the tension steel wire insertion groove 20X for the X-axis and the tension steel wire insertion groove 20Y for the Y-axis are formed. (a) shows an example in which a tension steel wire insertion groove 20X for the X-axis is formed on the upper side of the left column member 34a, a tension steel wire insertion groove 20Y for the Y-axis is formed on the lower side, a tension steel wire insertion groove 20X for the X-axis is formed on the upper side of the right column member 34b, and a tension steel wire insertion groove 20Y for the Y-axis is formed on the lower side. (b) shows an example in which a tension steel wire insertion groove 20X for the X-axis is formed on the upper side of the left column member 34a, and a tension steel wire insertion groove 20Y for the Y-axis is formed on the lower side of the right column member 34b. (c) shows an example in which a tension steel wire insertion groove 20X for the X-axis is formed on the upper side of the left column member 34a, a tension steel wire insertion groove 20Y for the Y-axis is formed on the lower side, a tension steel wire insertion groove 20Y for the Y-axis is formed on the upper side of the right column member 34b, and a tension steel wire insertion groove 20X for the X-axis is formed on the lower side. (d) shows an example in which a tension steel wire insertion groove 20X for the X-axis is formed on the upper side of the left column member 34a, and a tension steel wire insertion groove 20Y for the Y-axis is formed on the upper side of the right column member 34b. (e) shows an example in which a tension steel wire insertion groove 20X for the X-axis is formed on the upper side of the joint surface between the left column member 34a and the right column member 34b, and a tension steel wire insertion groove 20Y for the Y-axis is formed on the lower side. (f) shows an example in which a tension steel wire insertion groove 20Y for the Y-axis is formed on the lower side of the left column member 34a, and a tension steel wire insertion groove 20X for the X-axis is formed on the upper side of the right column member 34b. The above is an example, and other similar configurations can be adopted.

Embodiment

[0040] In Fig. 9, an example is shown in which when the width of the gap 33 between the two sets of protrusions 21 is widened and prestress is applied to the wooden structure 29, the long wooden structure 29 is actively curved by a distance C to form a curved wooden structure 29.

Example

[0041] In Fig. 10, not only one protrusion 21 is formed at approximately the center of the tensioned steel wire insertion groove 20 formed in the wooden structure 29, but also protrusions 21 are formed at every distance D of the tensioned steel wire insertion groove 20, and prestress may be applied by passing the tensioned steel wire 28 through these protrusions 21.

[0042] When the thickness of the pulling plate 30 is the depth at which the tensioned steel wire insertion groove 20 is formed, the tensioned steel wire insertion groove 20 having the protrusion 21 may be formed with a gap between the opposing surfaces of the two left and right pulling plates 30 laminated in the same layer.

Explanation of Reference Numerals

[0043] 10... Long structure, 11... Through hole, 12... Tension member, 13... Plate, 14... Fixing device (nut), 18... Tension member position retaining piece, 19... Fitting recess, 20... Tensioned steel wire insertion groove, 20X... Tensioned steel wire insertion groove for X-axis, 20Y... Tensioned steel wire insertion groove for Y-axis, 21... Protrusion, 22... Inclined surface, 23... Tensioned steel material contact surface, 24... Grooving mold, 25... Gap forming mold, 26... LVL type, 27... CLT type, 28... Tensioned steel wire, 29... Wooden structure, 30... Pulling plate, 31... Plate, 32... Fixing device, 33... Gap, 34... Column member, 35... Planar member, 36... Prestress device, 37... Beam member.

Claims

1. A veneer forming step of forming a plurality of veneers with the fiber direction in the longitudinal direction; A tensioned steel wire insertion groove forming step of forming a tensioned steel wire insertion groove over the entire length on the joint surface of one veneer with the other veneer, and forming protrusions protruding from both walls at positions where buckling deformation nodes of the tensioned steel wire insertion groove are desired; A wooden structure forming step of joining the one veneer in which the tensioned steel wire insertion groove is formed and the other veneer in which the tensioned steel wire insertion groove is not formed to form a wooden structure; An axial compression force applying step of inserting a tensioned steel wire of a prestressing device into the tensioned steel wire insertion groove to tension the tensioned steel wire, thereby applying an axial compression stress to the wooden structure, and fixing both ends of the tensioned steel wire with a fixing device at both ends of the wooden structure A method for manufacturing a prestressed wooden structure, characterized by comprising the above steps.

2. A veneer forming step of forming a plurality of veneers with the fiber direction in the longitudinal direction; A planar member forming step of joining the plurality of veneers with fiber directions intersecting each other to form a planar member; A tensioned steel wire insertion groove forming step of forming a tensioned steel wire insertion groove over the entire length on the joint surface of one veneer in which the planar member is formed with the other veneer, and forming protrusions protruding from both walls at positions where buckling deformation nodes of the tensioned steel wire insertion groove are desired; A wooden structure forming step of joining the one veneer in which the tensioned steel wire insertion groove is formed and the other veneer in which the tensioned steel wire insertion groove is not formed to form a planar wooden structure; An axial compression force applying step of inserting a tensioned steel wire of a prestressing device into the tensioned steel wire insertion groove to tension the tensioned steel wire, thereby applying an axial compression stress to the wooden structure, and fixing both ends of the tensioned steel wire with a fixing device at both ends of the wooden structure A method for manufacturing a prestressed wooden structure, characterized by comprising the above steps.

3. A veneer forming step of forming a plurality of veneers with the fiber direction in the longitudinal direction; A column member forming step of joining the plurality of veneers to form a column member; A tensioned steel wire insertion groove forming step of forming tensioned steel wire insertion grooves over the entire length at at least two joint surfaces of the other veneer of one veneer in which the column member is formed, and forming protrusions protruding from both walls at positions where buckling deformation nodes of the tensioned steel wire insertion groove are desired; A wooden structure constructing step of joining the one column member having the tension steel wire insertion groove formed therein and the other column member not having the tension steel wire insertion groove formed therein to form a columnar wooden structure; An axial compressive force applying step of inserting a tension steel wire of a prestressing device into the tension steel wire insertion groove and tensioning the tension steel wire to apply an axial compressive stress to the wooden structure, and fixing both ends of the tension steel wire with a fixing device at both ends of the wooden structure; A method for manufacturing a prestressed wooden structure, characterized by comprising the above steps.

4. The method for manufacturing a prestressed wooden structure according to claim 1, 2 or 3, wherein the protrusion is formed to protrude in the width direction of the pulling plate from both walls at a position where a buckling deformation node of the tension steel wire insertion groove is desired.

5. The method for manufacturing a prestressed wooden structure according to claim 1, 2 or 3, wherein the protrusion is formed to protrude in a direction orthogonal to the width direction of the pulling plate from both walls at a position where a buckling deformation node of the tension steel wire insertion groove is desired.

6. In a wooden structure formed by joining a plurality of pulling plates having a fiber direction in the longitudinal direction, A tension steel wire insertion groove is formed over the entire length on the joint surface of one pulling plate with the other pulling plate, and protrusions protruding from both walls at a position where a buckling deformation node in the middle of the tension steel wire insertion groove is desired are formed. The wooden structure is composed of a plurality of joined pulling plates with the tension steel wire insertion groove and protrusions formed thereon and pulling plates without the tension steel wire insertion groove and protrusions formed thereon. An axial compressive stress is applied to the wooden structure by inserting a tension steel wire of a prestressing device into the tension steel wire insertion groove and tensioning the tension steel wire, and both ends of the tension steel wire are fixed with a fixing device at both ends of the wooden structure. The prestressed wooden structure is characterized by applying an axial compressive force to the wooden structure so as to be in contact with the tension steel wire in the weak axis direction of the protrusion.

7. A prestressed wooden structure, comprising a planar member formed by joining a plurality of veneer sheets whose fiber directions are orthogonal to each other, and joining two or more of these planar members in the planar direction. A tension steel wire insertion groove is formed over the entire length of the joint surface of any one of the planar members to be joined. Protrusions are formed protruding from both walls at a position where buckling deformation nodes of the tension steel wire insertion groove are desired. A planar member having the tension steel wire insertion groove and the protrusions is joined to a planar member not having the tension steel wire insertion groove and the protrusions to form a planar wooden structure. A tension steel wire of a prestressing device is inserted into the tension steel wire insertion groove and tensioned to apply axial compressive stress to the wooden structure, and both ends of this tension steel wire are fixed by a fixing device at both ends of the wooden structure.

8. A prestressed wooden structure, comprising a columnar member formed by joining a plurality of veneer sheets whose fiber directions are in the longitudinal direction. Tension steel wire insertion grooves are formed over the entire length of at least two joint surfaces of the other veneer sheet in the one veneer sheet forming the columnar member. Protrusions are formed protruding from both walls at a position where buckling deformation nodes of the tension steel wire insertion groove are desired. One of the protrusions is formed protruding in the width direction of the veneer sheet from both walls at a position where buckling deformation nodes of the tension steel wire insertion groove are desired. The other protrusion is formed protruding in a direction orthogonal to the width direction of the veneer sheet from both walls at a position where buckling deformation nodes of the tension steel wire insertion groove are desired. A veneer sheet having the tension steel wire insertion groove and the protrusions is joined to a veneer sheet not having the tension steel wire insertion groove and the protrusions to form a columnar wooden structure. A tension steel wire of a prestressing device is inserted into the tension steel wire insertion groove and tensioned to apply axial compressive stress to the wooden structure, and both ends of this tension steel wire are fixed by a fixing device at both ends of the wooden structure.

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