A bamboo-based composite i-beam based on a co-extrusion technology
Bamboo-based composite I-beams manufactured using co-extrusion technology solve the problems of insufficient bending stiffness and excessive weight of bamboo-based composite beams through hollow circular hole groups and steel plate reinforcement structures, achieving efficient connection and low-carbon and environmentally friendly building applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SOUTH CHINA AGRICULTURAL UNIVERSITY
- Filing Date
- 2025-05-29
- Publication Date
- 2026-07-10
AI Technical Summary
Existing bamboo-based composite beams suffer from problems such as insufficient bending stiffness, excessive self-weight, brittle fracture, interfacial shear slip, and environmental pollution, which limit their application in construction.
Bamboo-based composite I-beams are manufactured using co-extrusion technology. By setting up hollow circular hole groups, flange steel plates, and web steel channels, combined with bolt connections, a solid web structure is formed, which enhances bending stiffness and shear resistance, avoids gluing processes, and achieves synergistic deformation and efficient connection of materials.
It improves the bending load-bearing capacity and stability of bamboo-based composite I-beams, reduces self-weight, reduces environmental pollution, enhances the seismic performance and durability of the structure, and meets green building standards.
Smart Images
Figure CN224478628U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of structural load-bearing columns, specifically to a bamboo-based composite I-beam based on co-extrusion technology. Background Technology
[0002] Currently, the most widely used structural beam types in the construction industry are reinforced concrete beams, steel beams, and timber beams. However, reinforced concrete beams are heavy, have long construction cycles, and have high carbon emissions from cement production; steel beams have poor corrosion resistance and high fire prevention costs; and timber beams have limited load-bearing capacity and are susceptible to insect infestation and cracking.
[0003] To address the insufficient mechanical properties of timber beams, existing technologies have proposed steel-timber composite beams, which enhance strength by bolting steel plates to the tension zone of the timber beams. However, this approach still suffers from problems such as stress concentration due to the anisotropy of timber, susceptibility to cracking after long-term use, insufficient bending stiffness, and limitations in load-bearing capacity and durability.
[0004] Bamboo-based composite materials (hereinafter referred to as "bamboo-based composites") are currently mainly used as decorative materials. However, they have significant characteristics such as high specific strength (tensile strength of 30-50MPa, density of only 1 / 5-1 / 4 of steel) and weather resistance (resistance to moisture, salt spray and ultraviolet rays). Theoretically, they can replace wood and solve the problems of wood being prone to cracking, low load-bearing capacity and durability in traditional solutions.
[0005] Despite the advantages of bamboo-based composites, such as lightweight, high strength, and weather resistance, a large-span steel-reinforced reconstituted bamboo composite beam disclosed in CN216475885U includes a steel reinforcement structure and reconstituted bamboo. The reconstituted bamboo has at least one row of steel reinforcement embedded within it. Each row consists of multiple steel bars laid parallel along the width of the composite beam, connected by connectors. The connectors and steel bars form a crisscrossing grid structure. This composite beam, through the combination of reconstituted bamboo and steel reinforcement, has the following problems: 1. Reconstituted bamboo exhibits brittle fracture characteristics, and the bottom area at the mid-span is prone to cracking due to reaching the ultimate tensile strain during bending.
[0006] 2. Reconstituted bamboo uses industrial structural adhesives, which pose environmental pollution problems during construction;
[0007] 3. In actual engineering, shear slip is prone to occur at the interface between steel bars and reconstituted bamboo, which leads to a reduction in the composite effect and a decrease in flexural bearing capacity.
[0008] Over the past two decades, researchers have explored composite forms of bamboo with various materials, achieving considerable results. Some composite methods have formed complete theoretical systems and have been successfully applied in low-carbon buildings. To date, research on bamboo composite structures mainly focuses on glued bamboo structures, bamboo-steel structures, and bamboo-concrete structures. However, the development of bamboo-based composite I-beams based on co-extrusion technology has not been reported. Co-extrusion technology is the most effective method for preparing multilayer structural composite materials. The development of bamboo-based composite structural materials based on co-extrusion technology has opened up a new field for the application of bamboo in low-density buildings. Co-extrusion technology effectively combines materials or chemical substances with different advantages to meet the different requirements of building structures in terms of ultimate load-bearing capacity and normal use. Through bolted connections, steel is used to reinforce the main stress areas of the beam flanges and web. Currently, there is no solution in the technology for using bamboo-based composites combined with steel as structural load-bearing beams. Summary of the Invention
[0009] The purpose of this utility model is to overcome the defects and deficiencies of the prior art and provide a bamboo-based composite I-beam based on co-extrusion technology. This bamboo-based composite I-beam based on co-extrusion technology solves the problems of heavy weight and brittle fracture in the prior art by setting the cross section, setting the hollow circular hole group, and setting the steel components, thereby optimizing the structural performance and durability.
[0010] To achieve the above objectives, the present invention adopts the following technical solution:
[0011] A bamboo-based composite I-beam based on co-extrusion technology includes a bamboo-based composite I-beam and flange steel plates;
[0012] The bamboo-based composite I-beam includes a bamboo-based composite I-beam frame and a bamboo-based composite interlayer; the bamboo-based composite I-beam frame includes an upper flange frame, a web frame and a lower flange frame connected in sequence; the bamboo-based composite interlayer encloses at least two rows of hollow circular holes in the upper flange frame and the lower flange frame respectively; each row of hollow circular holes includes at least five circular holes penetrating along the length of the bamboo-based composite I-beam frame; the number of rows of hollow circular holes and the number of circular holes in a single row are adapted to the arrangement requirements of the reinforcing bars.
[0013] The flange steel plates are respectively fixed to the outer sides of the upper flange frame and the lower flange frame.
[0014] As a preferred embodiment, it also includes reinforcing bars inserted into a circular hole.
[0015] As a preferred embodiment, the system also includes a web steel channel, which is fixed to both sides of the web frame.
[0016] As a preferred embodiment, the flange steel plate is fixed to the outer side of the upper flange frame and the lower flange frame respectively by connecting bolts.
[0017] As a preferred embodiment, the web steel channel is fixed to both sides of the web frame by connecting bolts.
[0018] As a preferred embodiment, the cross-section of the bamboo-based composite I-beam is a solid web structure.
[0019] As a preferred embodiment, the corners of the bamboo-based composite I-beam are rounded.
[0020] As a preferred option, the bamboo-based composite I-beam frame and the bamboo-based composite partition are manufactured by co-extrusion molding.
[0021] As a preferred option, bamboo-based composite I-beams and reinforcing bars are manufactured through co-extrusion molding.
[0022] In summary, this utility model has the following advantages:
[0023] 1. This utility model's bamboo-based composite I-beam, based on co-extrusion technology, uses bamboo-based composite as its base material. Its unique fiber structure endows the bamboo-based composite I-beam with excellent bending and shear resistance, enhancing the overall load-bearing capacity and stability of the structure. Through the I-beam cross-section design, the moment of inertia is optimized, improving bending stiffness compared to existing rectangular cross-section composite beams. The use of hollow circular holes not only disperses stress and reduces tensile strain at the mid-span bottom, preventing brittle fracture, but also significantly reduces the beam's self-weight, decreasing foundation load and saving construction costs. By fixing flange steel plates to the outer sides of the upper and lower flange frames, these plates act as reinforcement, compensating for the insufficient tensile strength of the bamboo-based composite. While enhancing the load-bearing capacity of the tension / compression zones, they work synergistically with the bamboo-based composite, effectively dispersing stress, coordinating deformation, improving the structure's bending load-bearing capacity, and preventing bending failure and lateral torsional instability of the structural beam.
[0024] 2. This utility model uses bamboo-based composite materials. Compared with ordinary wood and glued bamboo, bamboo-based composite materials have better mechanical properties and have significant advantages in compressive strength and bending strength. In addition, bamboo-based composite materials are renewable and can reduce carbon emissions and environmental pollution compared with concrete and steel, thus meeting the requirements of green building.
[0025] 3. This utility model pre-sets hollow circular holes on the upper and lower flange frames. The circular holes are adapted to the arrangement requirements of the reinforcing bars, which can avoid stress concentration caused by on-site drilling. By inserting reinforcing bars into the circular holes, the overall stiffness and bending resistance of the bamboo-based composite I-beam based on co-extrusion technology are further improved.
[0026] 4. This utility model enhances the lateral stiffness and shear resistance of bamboo-based composite I-beams by setting web steel channels. At the same time, the web steel channels on both sides of the web frame act as lateral supports for the bamboo-based composite I-beams, preventing bending and torsional instability of the bamboo-based composite I-beams under load, suppressing buckling deformation of the web frame, and improving the overall stability of bamboo-based composite I-beams based on co-extrusion technology.
[0027] 5. This utility model, through the arrangement of flange steel plates and web steel channels, enables the steel and bamboo-based composite I-beams to possess good synergistic deformation capabilities: steel plates are used to reinforce the key stress areas of the upper and lower flanges of the bamboo-based composite I-beams, effectively limiting the deformation of the bamboo-based composite I-beams. Under dynamic loads such as earthquakes, the bamboo-based composite and steel plates each leverage their respective material advantages to effectively absorb and dissipate energy; the high yield strength of the steel plates and the fiber stretching and fracture processes of the bamboo-based composite can convert the energy of external loads into internal elastic deformation energy, improving the seismic performance of the structural beam.
[0028] 6. The web steel channel and flange steel plate of this utility model are mechanically interlocked with the bamboo-based composite I-beam by connecting bolts, and the structural connection is reliable. When it is at the elastic critical bearing limit, the flange steel plate and web steel channel can continue to bear the bending moment and enter the elastic-plastic deformation stage; and there is no glue process, which meets the green building standards.
[0029] 7. The bamboo-based composite I-beam of this utility model based on co-extrusion technology is I-shaped in general. The bamboo-based composite I-beam concentrates the material in the upper and lower flanges (tension / compression zone), and the web only bears the shear force, which improves the cross-sectional utilization rate and reduces the weight under the same load-bearing capacity. By setting the cross-section of the bamboo-based composite I-beam as a continuous and uninterrupted solid web structure, local buckling caused by stress concentration can be avoided, and the resistance to local buckling of the bamboo-based composite I-beam based on co-extrusion technology can be improved.
[0030] 8. This utility model rounds the corners of the bamboo-based composite I-beam, which makes the stress distribution uniform, eliminates stress concentration points at sharp corners, and extends the fatigue life of the bamboo-based composite I-beam based on co-extrusion technology.
[0031] 9. The bamboo-based composite I-beam frame and the bamboo-based composite partition of this utility model are integrally formed by co-extrusion molding process, which avoids the risk of delamination between the bamboo-based composite I-beam frame and the bamboo-based composite partition, replaces the gluing process, and eliminates industrial glue pollution.
[0032] 10. The bamboo-based composite I-beam and the reinforcing steel of this utility model are integrally formed by co-extrusion molding process. The reinforcing steel and the bamboo-based composite I-beam form a physical interlocking, which improves the interfacial bonding strength and interfacial tensile strength between the bamboo-based composite I-beam and the reinforcing steel, while avoiding the pollution caused by the gluing process. Attached Figure Description
[0033] Figure 1 This is a cross-sectional view of the bamboo-based composite I-beam of Example 2.
[0034] Figure 2 This is a three-dimensional structural schematic diagram of the bamboo-based composite I-beam of Example 2.
[0035] Figure 3 This is a cross-sectional view of the bamboo-based composite I-beam based on co-extrusion technology in Example 2.
[0036] Figure 4 This is a three-dimensional structural schematic diagram of the bamboo-based composite I-beam based on co-extrusion technology in Example 2.
[0037] Figure 5 This is a cross-sectional view of the bamboo-based composite I-beam based on co-extrusion technology in Example 3.
[0038] Figure 6 This is a three-dimensional structural schematic diagram of the bamboo-based composite I-beam based on co-extrusion technology in Example 3.
[0039] Wherein: 1 is bamboo-based composite I-beam, 11 is upper flange frame, 12 is web frame, 13 is lower flange frame, 2 is reinforcing bar, 3 is flange steel plate, 4 is web steel channel, and 5 is connecting bolt. Detailed Implementation
[0040] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0041] Bamboo-based composites are a new type of material made primarily of bamboo, combined with high-performance reinforcing materials such as resin and fiber. They are high-performance composite materials manufactured through processes such as prepreg technology, vacuum infusion, and compression molding. This material can be made into products of various shapes and sizes using multiple processes, is simple to process, low in cost, and can also be surface-treated. It inherently provides heat and sound insulation, and the composite effect is even more significant, exhibiting higher strength, stiffness, and durability. By adding other materials, its mechanical properties are enhanced, making it suitable for applications requiring high resistance to bending and shearing.
[0042] Example 1
[0043] A bamboo-based composite I-beam based on co-extrusion technology includes a bamboo-based composite I-beam and a flange steel plate; the bamboo-based composite I-beam includes a bamboo-based composite I-beam frame and a bamboo-based composite partition, which are manufactured by co-extrusion molding.
[0044] The bamboo-based composite I-beam frame includes an upper flange frame, a web frame, and a lower flange frame connected in sequence. The bamboo-based composite partition separates two rows of hollow circular holes within the upper and lower flange frames, respectively. Each row of hollow circular holes includes five circular holes that penetrate along the length of the bamboo-based composite I-beam frame. The number of rows of hollow circular holes and the number of holes in a single row are adapted to the arrangement requirements of the reinforcing bars.
[0045] The flange steel plates are fixed to the outer sides of the upper flange frame and the lower flange frame respectively by connecting bolts.
[0046] The cross-section of the bamboo-based composite I-beam is a solid web structure.
[0047] The corners of the bamboo-based composite I-beam are rounded.
[0048] The bamboo-based composite material used in this invention has a bamboo fiber ratio of >65% and a plastic ratio of <30%, and belongs to a highly filled bamboo-based composite structural material. Its characteristic is that it is biodegradable.
[0049] Example 2
[0050] A bamboo-based composite I-beam based on co-extrusion technology includes a bamboo-based composite I-beam, flange steel plates, and reinforcing bars.
[0051] like Figure 1 and Figure 2 As shown, the bamboo-based composite I-beam includes a bamboo-based composite I-beam frame and a bamboo-based composite interlayer; the bamboo-based composite I-beam frame includes an upper flange frame, a web frame and a lower flange frame connected in sequence; the bamboo-based composite interlayer encloses two rows of hollow circular holes in the upper flange frame and the lower flange frame respectively; each row of hollow circular holes includes five circular holes that penetrate along the length of the bamboo-based composite I-beam frame; the number of rows of hollow circular holes and the number of circular holes in a single row are adapted to the arrangement requirements of the reinforcing bars;
[0052] The reinforcing bars are inserted into the round holes, and the bamboo-based composite I-beams and reinforcing bars are manufactured by co-extrusion molding.
[0053] like Figure 3 and Figure 4 As shown, the flange steel plate is fixed to the outer side of the upper flange frame and the lower flange frame respectively by connecting bolts.
[0054] The cross-section of the bamboo-based composite I-beam is a solid web structure.
[0055] The corners of the bamboo-based composite I-beam are rounded.
[0056] Example 3
[0057] like Figure 5 and Figure 6As shown, the difference between this embodiment and embodiment 2 is that the bamboo-based composite I-beam based on co-extrusion technology also includes a web steel channel, which is fixed to both sides of the web frame by connecting bolts.
[0058] In summary, this utility model improves bending stiffness and reduces ultimate tensile strain by setting the I-beam cross section and hollow circular holes to disperse stress; it achieves zero pollutant emissions while avoiding easy slippage of the adhesive interface through bolted connection and co-extrusion glue-free process; it improves shear strength through the composite structure of flange steel plate and web steel channel; and it improves interface bonding strength through co-extrusion integral molding process.
[0059] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.
Claims
1. A bamboo-based composite I-beam based on co-extrusion technology, characterized in that: Including bamboo-based composite I-beams and flange steel plates; The bamboo-based composite I-beam includes a bamboo-based composite I-beam frame and a bamboo-based composite partition. The bamboo-based composite I-beam frame and the bamboo-based composite partition are manufactured by co-extrusion molding. The bamboo-based composite I-beam frame includes an upper flange frame, a web frame, and a lower flange frame connected in sequence. The bamboo-based composite partition has at least two rows of hollow circular holes in the upper flange frame and the lower flange frame, respectively. Each row of hollow circular holes includes at least five circular holes that penetrate along the length of the bamboo-based composite I-beam frame. The flange steel plates are respectively fixed to the outer sides of the upper flange frame and the lower flange frame.
2. The bamboo-based composite I-beam based on co-extrusion technology according to claim 1, characterized in that: It also includes reinforcing bars, which are inserted into the round hole.
3. The bamboo-based composite I-beam based on co-extrusion technology according to claim 1, characterized in that: It also includes a web steel channel, which is fixed to both sides of the web frame.
4. The bamboo-based composite I-beam based on co-extrusion technology according to claim 1, characterized in that: The flange steel plates are fixed to the outer sides of the upper flange frame and the lower flange frame respectively by connecting bolts.
5. A bamboo-based composite I-beam based on co-extrusion technology according to claim 3, characterized in that: The web steel channel is fixed to both sides of the web frame by connecting bolts.
6. A bamboo-based composite I-beam based on co-extrusion technology according to claim 1, characterized in that: The cross-section of the bamboo-based composite I-beam is a solid web structure.
7. A bamboo-based composite I-beam based on co-extrusion technology according to claim 1, characterized in that: The corners of the bamboo-based composite I-beam are rounded.
8. A bamboo-based composite I-beam based on co-extrusion technology according to claim 2, characterized in that: Bamboo-based composite I-beams and reinforcing bars are manufactured through co-extrusion molding.