CN116335339B

CN116335339B - Variable stiffness wooden beam, building structure and preparation method

Info

Publication number: CN116335339B
Application number: CN202310394085.5A
Authority: CN
Inventors: 方立新; 孙逊; 凌灼灼; 李剑
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2023-04-13
Filing date: 2023-04-13
Publication date: 2025-08-26
Anticipated expiration: 2043-04-13
Also published as: CN116335339A

Abstract

The present invention discloses a variable stiffness wooden beam, a building structure and a preparation method, which belong to the field of civil engineering. A composite wooden beam with a large height-to-span ratio is formed by stacking multiple layers of flat wooden board sheets. The combined action between the stacked flat beams of each layer is achieved by structures such as (1) hook and loop fasteners of the stacked layers, (2) end caps of the stacked wooden beams and (3) FRP composite material hoops on the stacked wooden beams. That is, the above structures provide a function similar to a shear key of the composite beam to form a complete or partial shear connection between the stacked beams. In the variable stiffness wooden beam provided by the present invention, under a severe earthquake, the FRP composite material hoops and the end caps are deformed and fail, and at the same time, the hook and loop fasteners slip, causing the combined action between the stacked layers to fail, thereby reducing the stiffness of the composite beam and being able to adapt to the large deformation requirements under a severe earthquake without causing breakage of the wooden beam or the node.

Description

Rigidity-variable wood beam, building structure and preparation method

Technical Field

The invention relates to the field of civil engineering, in particular to a rigidity-variable wood beam.

Background

In the construction production process, the ecological environment is protected, and the energy conservation, the land conservation and the material conservation are realized. The wood structure has the characteristics of simplicity and convenience in material selection and processing, low carbon, environmental friendliness, recycling and the like, and is short in construction period, good in heat preservation performance and wide in application and development space in the future. Due to the characteristics of wood materials, the section height of the wood beam is generally far greater than the height of a steel beam or a concrete beam under the same load level when the span is large, and the material drawing and manufacturing of the large-section wood beam are limited in practice, so that the application scene of the wood structure is influenced. On the other hand, due to the lower strength of wood, the large-section wood beam lacks the capability of adapting to large deformation in actual use, such as easy breakage or damages or tenoning of beam column joints when encountering large shock, which also leads to the fact that the so-called wood structure has good energy consumption characteristics and cannot be effectively played and truly embodied.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the variable-rigidity wood beam, which is formed by constructing and combining the wood beams with wide and large surface and small cross section, has the characteristics of variable rigidity and energy consumption, can keep enough rigidity under normal use load, can complete rigidity release through interlayer sliding under the condition of large earthquake, avoids the fracture and the damage of the wood beam, and simultaneously realizes effective energy consumption by means of interlayer friction.

The aim of the invention can be achieved by the following technical scheme:

a first aspect of the present application provides a variable stiffness wood beam comprising:

the wood beam sheets are overlapped through bonding of the primary and secondary sticky buckles;

the sealing plates are symmetrically arranged on two sides of the wood beam sheet, and the superposition body of the wood beam sheet is connected with the sealing plates;

and the FRP composite material is used for tightly holding the laminated body of the wood beam sheet.

In some embodiments, one of the two adjacent wood beam sheets is provided with a rough surface of the primary-secondary fastening tape, the other wood beam sheet is provided with a hook surface of the primary-secondary fastening tape, and the rough surface of the primary-secondary fastening tape is connected with the hook surface of the primary-secondary fastening tape in a position.

In some embodiments, the wood beam piece is sized to have an aspect ratio of 0.3 or less.

In some embodiments, the FRP composite is equally spaced on the laminate of wood beam sheets.

In some embodiments, the wood beam pieces are bonded to the primary and secondary fastening strips, the closure plate, and the FRP composite by epoxy glue.

A second aspect of the application provides a building structure constructed from a variable stiffness wood beam according to the first aspect of the application.

A third aspect of the present application provides a method for manufacturing a variable stiffness wood beam according to the first aspect of the present application, comprising the steps of:

The hook surface and the haired surface of the primary-secondary fastening tape are respectively stuck on two sides of the wood beam sheet, wherein the wood beam sheet of the first layer and the bottom layer is only stuck with the hook surface or the haired surface of the primary-secondary fastening tape stuck with the adjacent layer;

bonding and superposing the wood beam sheets through the hook surface and the rough surface of the primary-secondary fastening tape;

And tightly holding the FRP composite material on the laminated body of the wood beam sheet, and bonding the FRP composite material and the laminated body of the wood beam sheet.

The invention has the beneficial effects that:

The invention forms a combined wood beam with large span ratio through the superposition of multiple layers of flat wood plate sheets, and the combined action between the laminated flat beams is realized through structures such as (1) a primary and secondary adhesive tape (HOOK & LOOP) of a superposition layer, (2) two end sealing plates of the superposition wood beam, and (3) FRP composite materials on the superposition wood beam, namely the structure provides a function similar to a shear key of the combined beam to form complete or partial shear connection between the superposition wood beams.

According to the rigidity-variable wood beam, under a large earthquake, the FRP composite material and the two end sealing plates are deformed and fail, meanwhile, the primary and secondary fastening belts slide, the combination effect between the layers fails, so that the rigidity of the combined beam is reduced, and the rigidity-variable wood beam can adapt to the large deformation requirement under the large earthquake without breaking the wood beam or the joint. Meanwhile, each layer of superimposed flat beams is still in an elastic state under a large earthquake, deformation can be recovered, and development of post-earthquake repair work is facilitated.

The composite plate adopts the primary and secondary fastening tapes as the laminated layers of the wood beam sheets, the friction layers formed by the primary and secondary fastening tapes in each layer can obtain larger sliding friction stroke under large vibration, the energy consumption can be effectively realized, meanwhile, the characteristic that the fastening force can be quickly recovered after the primary and secondary fastening tapes are stopped in sliding is utilized, the rapid decline of the residual bearing capacity of the wood beam is avoided, and the sudden collapse of the structure possibly occurring after the earthquake is damaged is prevented.

The wood beam provided by the invention is composed of the standard components of wood beam sheets, the primary-secondary fastening tape, the FRP composite material and the sealing plate, and the repair work of the structure is completed by replacing the local components under the condition that part of standard components are damaged, so that the problem that the existing wood beam is difficult to repair after being broken is solved, and the restorability of the wood beam is embodied.

Drawings

The invention is further described below with reference to the accompanying drawings.

FIG. 1 is a schematic perspective view of a variable stiffness wood beam according to the present invention;

FIG. 2 is a schematic perspective view of a standard layer wood beam sheet bonding primary-secondary fastening tape according to the present invention;

Fig. 3 is a schematic perspective view of the female fastening tape of the present invention;

FIG. 4 is an exploded view of the variable stiffness wood beam of the present invention;

FIG. 5 is a schematic assembly view of the wood beam sheet of the present invention with the primary and secondary fastening tapes aligned for bonding;

FIG. 6 is a schematic view of the splice of the present invention with a laminate of plates and sheets of wood beams aligned for bonding;

FIG. 7 is a schematic diagram of the assembly of FRP composite material forming a wood beam hoop;

fig. 8 is a schematic cross-sectional view of a 6-layer laminated variable stiffness wood beam and an unclassified whole beam, wherein (a) is a schematic cross-sectional view of the 6-layer laminated variable stiffness wood beam, and (b) is a schematic cross-sectional view of the unclassified whole beam.

The composite material comprises the following components of 1, a wood beam piece, 2, a primary and secondary fastening tape, 201, a rough surface of the primary and secondary fastening tape, 202, a hook surface of the primary and secondary fastening tape, 3, a sealing plate and 4, and an FRP composite material.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the description of the present invention, it should be understood that the terms "open," "upper," "lower," "thickness," "top," "middle," "length," "inner," "peripheral," and the like indicate orientation or positional relationships, merely for convenience in describing the present invention and to simplify the description, and do not indicate or imply that the components or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.

In the description of the present specification, the descriptions of the terms "one embodiment," "example," "specific example," and the like, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Embodiment 1 As shown in fig. 1, the rigidity-variable wood beam provided by the invention comprises a wood beam sheet 1, a primary-secondary fastening tape 2, a sealing plate 3 and an FRP composite material 4.

As shown in fig. 2, the primary-secondary fastening tape 2 comprises a hair surface 201 of the primary-secondary fastening tape and a hook surface 202 of the primary-secondary fastening tape, the primary-secondary fastening tape 2 is bonded by the wood beam sheet 1 through epoxy resin glue in the sequence of a first layer, a standard layer and a bottom layer, and fig. 2 shows the standard layer wood beam sheet 1, specifically, the hair surface 201 of the primary-secondary fastening tape is bonded on the upper surface of the wood beam sheet 1, and the hook surface 202 of the primary-secondary fastening tape is bonded on the lower surface.

As shown in fig. 3, 6 wood beam sheets are stacked in total, and the wood beam sheet 1 is divided into a first layer (1 sheet), a standard layer (4 sheets) and a bottom layer (1 sheet). The primary-secondary fastening tape 2 is specifically positioned in such a way that the hook surface 202 of the primary-secondary fastening tape is adhered to the lower surface of the primary-layer wood beam sheet 1, the hair surface 201 of the primary-secondary fastening tape is adhered to the upper surface of the standard-layer wood beam sheet 1, the hook surface 202 of the primary-secondary fastening tape is adhered to the lower surface, and the hair surface 201 of the primary-secondary fastening tape is adhered to the upper surface of the bottom-layer wood beam sheet 1. When the wood beam sheet 1 and the primary and secondary fastening tape 2 are bonded in alignment, the effective epoxy resin glue is used to ensure the close combination of the wood beam sheet 1 and the primary and secondary fastening tape, and the slippage is avoided.

The assembly and connection of the wood beams are carried out according to the following procedures. First, the wood beam sheet is bonded in alignment. As shown in fig. 4, the 6 layers of wood beam sheets 1 bonded with the primary and secondary fastening tapes 2 are aligned and connected through the rough surface 201 of the primary and secondary fastening tapes and the hook surface 202 of the primary and secondary fastening tapes according to the sequence of the first layer, the standard layer and the bottom layer, and are folded to form the laminated body of the wood beam sheets in fig. 5. Then, the overlapping body of the sealing plate 3 and the wood beam sheet is bonded in alignment. The sealing plate 3 is aligned to the section of the wood beam, and the lamination body of the sealing plate 3 and the wood beam sheet is bonded to form the integral structure of fig. 6 by using effective epoxy resin glue. Finally, the FRP composite material 4 is formed into a wood beam hoop, the FRP composite material 4 is distributed at equal intervals along the axial direction of the wood beam, the laminated body of the wood beam sheet is held tightly, the FRP composite material 4 is bonded around the circumferential direction of the wood beam by using effective epoxy resin glue, the wood beam hoop is formed, and finally the variable-rigidity wood beam structure provided by the invention is formed, as shown in figure 7.

In order to illustrate the advantages of the variable stiffness wood beam structure provided by the invention, under the condition of extreme complete sliding, the bending stiffness difference between the variable stiffness wood beam formed by overlapping 6 layers of wood beam sheets and the non-layered whole beam in the specific embodiment is calculated, and the schematic cross section of the variable stiffness wood beam is shown in fig. 8.

For the variable-rigidity wood beam formed by overlapping 6 layers of wood beam sheets, a schematic cross-sectional view is shown in fig. 8 (a), and the calculation formula of the cross-sectional moment of inertia of each layer is as follows:

the overall flexural rigidity is:

For an integral beam which is not layered, a schematic cross-sectional view is shown in fig. 8 (b), and the calculation formula of the cross-sectional moment of inertia is:

The flexural rigidity is:

the flexural rigidity of the two is compared:

it can be seen that in the case of extreme complete slip, the ratio of the bending stiffness of the variable stiffness wood beam formed by the superposition of 6 layers of wood beam sheets to the bending stiffness of the non-layered whole beam is 1/36. Therefore, by selecting the number of superimposed layers n of the wood beam, the rigidity reduction level is changed, so that the wood beam has the property of variable rigidity.

The foregoing has shown and described the basic principles, principal features and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims.

Claims

1. A variable stiffness wooden beam, comprising:

Wooden beam pieces, the wooden beam pieces are stacked by bonding with hook and loop fasteners;

Closing plates, the closing plates are symmetrically arranged on both sides of the wooden beam pieces; the superimposed body of the wooden beam pieces is connected to the closing plates;

An FRP composite material, wherein the FRP composite material tightly embraces the laminated body of the wood beam sheets;

Under a major earthquake, the FRP composite material and the end caps deform and fail, and the Velcro straps slip, causing the combined effect between the layers to fail, reducing the stiffness of the composite beam. This allows it to adapt to the large deformation requirements under a major earthquake without causing breakage of the wooden beams or nodes.

2. The variable stiffness wooden beam according to claim 1 is characterized in that, among the two adjacent wooden beam pieces, one wooden beam piece is installed with the rough surface of the parent-child Velcro, and the other wooden beam piece is installed with the hook surface of the parent-child Velcro; the rough surface of the parent-child Velcro is connected to the hook surface of the parent-child Velcro.

3. The variable stiffness wooden beam according to claim 1, wherein the dimensions of the wooden beam piece are limited to a height-to-width ratio of less than or equal to 0.3.

4 . The variable stiffness wooden beam according to claim 1 , wherein the FRP composite material is distributed at equal intervals on the laminated body of the wooden beam sheets.

5. The variable stiffness wooden beam according to claim 1, wherein the wooden beam pieces are bonded to the hook and loop fasteners, the sealing plate and the FRP composite material by epoxy resin glue.

6. A building structure, characterized in that it is constructed by using the variable-rigidity wooden beam according to any one of claims 1 to 5.

7. A method for preparing a variable stiffness wooden beam according to any one of claims 1 to 5, characterized in that it comprises the following steps:

The hook side and the hair side of the parent-child hook and loop fastener are respectively adhered to both sides of the wooden beam piece; wherein the wooden beam pieces of the first layer and the bottom layer are only adhered to the hook side or the hair side of the parent-child hook and loop fastener adhered to the adjacent layer;

The wooden beam pieces are bonded and overlapped by means of the hook surface and the hair surface of the parent-child hook and loop fastener; and the sealing plates are bonded to both sides of the overlapped body of the wooden beam pieces;

The FRP composite material is tightly embraced by the superposition body of the wood beam pieces, and the FRP composite material and the superposition body of the wood beam pieces are bonded.