Steel-bamboo-concrete composite t-beam and construction method thereof

Abstract

The application discloses a kind of steel-bamboo-concrete combination T beam and its construction method, including UHPC prefabricated bridge deck, steel-bamboo combination beam frame and shear connector, UHPC prefabricated bridge deck is erected on steel-bamboo combination beam frame and is positioned by shear connector, steel-bamboo combination beam frame includes steel-bamboo combination prefabricated T beam, steel-bamboo combination cross beam and prestressed tendon, multiple steel-bamboo combination prefabricated T beam is sequentially arranged along transverse direction and effectively connected, steel-bamboo combination cross beam is arranged at the transverse connection position of steel-bamboo combination prefabricated T beam, and the both ends of steel-bamboo combination cross beam are fixedly connected with corresponding steel-bamboo combination prefabricated T beam respectively.The steel-bamboo-concrete combination T beam of the application, relative to the weight of the whole structure combination of existing concrete bridge is reduced, and the excellent characteristics of various materials are combined to improve the strength, stiffness and durability of steel-bamboo-concrete combination T beam, has huge application potential and ecological economic value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridges, in particular to a steel-bamboo-concrete combined T beam and a construction method thereof. BACKGROUND

[0002] Bamboo is an excellent natural fast-growing tree-like grass plant. Bamboo has been used as a structural material for thousands of years. Houses made of natural bamboo have existed since the Neolithic Age. As an irreplaceable cultural symbol, the traditional bamboo culture is deeply rooted and has a long history.

[0003] Most existing bridges use a large amount of steel and concrete materials, but have the following disadvantages: large self-weight, which reduces the economy of the structure; insufficient durability, the concrete bridge deck is prone to cracking and leaking, and the steel is prone to corrosion and rust, which increases the maintenance cost in the later period; great impact on the environment, which produces a certain degree of environmental pollution in the production, transportation and installation process; and a large amount of construction waste is generated after the service life.

[0004] Therefore, it is necessary to provide a steel-bamboo-concrete combined T beam to solve or at least alleviate the above-mentioned defects. SUMMARY

[0005] The main purpose of the present application is to provide a steel-bamboo-concrete combined T beam and a construction method thereof, which aims to solve the technical problems of the existing concrete bridge, such as large amount of concrete, and a large amount of construction waste generated after the service life.

[0006] To achieve the above-mentioned purpose, the present application provides a steel-bamboo-concrete combined T beam, which comprises a UHPC prefabricated bridge deck, a steel-bamboo combined beam frame and a shear connector. The UHPC prefabricated bridge deck is positioned on the steel-bamboo combined beam frame through the shear connector. The steel-bamboo combined beam frame comprises a steel-bamboo combined prefabricated T beam, a steel-bamboo combined cross beam and a prestressed tendon. A plurality of steel-bamboo combined prefabricated T beams are arranged in sequence along the transverse direction and cemented, and the transversely adjacent steel-bamboo combined prefabricated T beams are fixedly connected through the corresponding steel-bamboo combined cross beam. The steel-bamboo combined cross beam is arranged at the transverse connection position of the steel-bamboo combined prefabricated T beam and between the two steel-bamboo combined prefabricated T beams along the transverse direction. The two ends of the steel-bamboo combined cross beam are fixedly connected with the corresponding steel-bamboo combined prefabricated T beam. The prestressed tendon is tensioned along the longitudinal direction at the bottom of the steel-bamboo combined prefabricated T beam. The UHPC prefabricated bridge deck is arranged on the steel-bamboo combined prefabricated T beam. The first end of the shear connector is connected with the steel-bamboo combined prefabricated T beam, and the second end of the shear connector is connected with the UHPC prefabricated bridge deck.

[0007] Furthermore, the steel-bamboo composite precast T-beam includes a bamboo T-beam body and a cold-formed thin-walled steel reinforcement. The flange sidewalls of two adjacent bamboo T-beam bodies are glued together in the transverse direction. The prestressing tendons are tensioned in the longitudinal direction at the bottom of the bamboo T-beam body. The cold-formed thin-walled steel reinforcement is located at the reinforcement position of the bamboo T-beam body and is wrapped around the bamboo T-beam body. The cold-formed thin-walled steel reinforcement is fixedly connected to the bamboo T-beam body.

[0008] Furthermore, the cold-formed thin-walled steel reinforcement includes an outer beam rib cold-formed thin-walled steel section located at the beam rib position of the bamboo T-beam, an outer horseshoe cold-formed thin-walled steel section located at the horseshoe position of the bamboo T-beam, and an outer flange cold-formed thin-walled steel section located at the flange position of the bamboo T-beam. The outer flange cold-formed thin-walled steel section, the outer beam rib cold-formed thin-walled steel section, and the outer horseshoe cold-formed thin-walled steel section are integrally formed and fixedly connected to the bamboo T-beam.

[0009] Furthermore, the steel-bamboo composite precast T-beam also includes steel end caps located at both longitudinal ends of the bamboo T-beam body, and the steel end caps are fixedly connected to the ends of the bamboo T-beam body.

[0010] Furthermore, the top surface of the bamboo T-beam is recessed with a receiving groove, which is located at the transverse mid-section of the bamboo T-beam. The receiving groove is a trapezoidal groove with the diameter decreasing from top to bottom. The UHPC precast bridge deck has pre-reserved casting holes. The shear connector includes a grooved shear key and a post-cast concrete structure. The grooved shear key is embedded in the receiving groove, and shear nails are arranged in the shear groove of the grooved shear key. The shear nails extend outward and protrude to the top surface of the bamboo T-beam. The UHPC precast bridge deck is erected on the bamboo T-beam, and the casting holes and shear grooves are combined to form a casting groove. UHPC concrete is then poured into the casting groove to form the post-cast concrete structure.

[0011] Furthermore, the outer wall of the grooved shear key is bonded to the groove wall of the receiving groove, and the bottom surface of the grooved shear key is fixedly connected to the bottom of the receiving groove by a connecting bolt. The shear connector is a grooved shear connector with the second end gradually narrowing from the top to the bottom.

[0012] Furthermore, the exterior of the steel-bamboo composite precast T-beam is coated with an anti-corrosion layer.

[0013] Furthermore, the steel-bamboo composite crossbeam includes a bamboo crossbeam, steel panels, connecting screws, and connecting bolts. Two steel panels are positioned opposite each other at the transverse ends of the bamboo crossbeam. The steel panels are inserted into the transverse end edges of the corresponding bamboo crossbeam through lateral openings. The steel panels are glued to the bamboo crossbeam. The connecting screws pass through the steel panels and extend into the bamboo crossbeam. The steel panels protrude from the wall of the bamboo crossbeam and have connecting holes. The connecting bolts pass through the connecting holes and are fixedly connected to the bamboo T-beam body.

[0014] Furthermore, the UHPC prefabricated bridge deck includes prefabricated panels, with multiple prefabricated panels arranged longitudinally and spliced ​​together by seams.

[0015] The present invention also provides a method for constructing a steel-bamboo-concrete composite T-beam, which includes the following steps:

[0016] On-site construction of steel-bamboo composite beam frame involves splicing multiple precast steel-bamboo composite T-beams with cold-formed thin-walled steel reinforcements laterally, bonding the flange sidewalls of adjacent precast steel-bamboo composite T-beams together; fixing adjacent precast steel-bamboo composite T-beams together with steel-bamboo composite crossbeams; and tensioning the prestressing tendons of each precast steel-bamboo composite T-beam.

[0017] The grooved shear key for installing the shear connector is arranged in the corresponding groove on the top surface of the bamboo T-beam, so that the outer wall of the grooved shear key is bonded to the groove wall of the groove, the connecting bolt is inserted into the bottom surface of the groove, and the shear nail extends to the top surface of the bamboo T-beam.

[0018] Precast panels are laid longitudinally, and positioning holes and shear grooves are combined to form a casting groove. UHPC concrete is then poured into the casting groove to form a post-cast concrete structure for installing shear connectors, so that adjacent precast panels are connected by splicing joints.

[0019] Secondary tensioning of prestressed tendons.

[0020] Compared with the prior art, the steel-bamboo-concrete composite T-beam provided by the present invention has the following beneficial effects:

[0021] This invention provides a steel-bamboo-concrete composite T-beam, comprising a UHPC precast bridge deck, a steel-bamboo composite beam frame, and shear connectors. The UHPC precast bridge deck is supported by a steel-bamboo composite beam frame. The UHPC precast bridge deck is made of UHPC concrete with high tensile strength, while the steel-bamboo composite beam frame is made of bamboo and receives auxiliary support from the steel. Both bamboo and UHPC materials possess high tensile and compressive strength. The addition of steel for auxiliary support improves the bending stiffness of the bamboo, overcoming the technical problem of relatively low bending stiffness when supported solely by bamboo. This invention also addresses the issues of large concrete consumption and short service life in existing concrete bridges. The technical problem of generating a large amount of construction waste after completion can be addressed by adopting a structure of longitudinally continuous segments and laterally segmented splicing of steel-bamboo composite precast T-beams. By using UHPC precast bridge decks and steel-bamboo composite precast T-beams for positioning and connection through shear connectors, and further constraining the steel-bamboo composite precast T-beams arranged laterally using UHPC precast bridge decks, the combination of UHPC material structure, bamboo structure and steel structure reduces the weight of the entire structural assembly compared to existing concrete bridges. The excellent properties of various materials are combined to improve the strength, stiffness and durability of the steel-bamboo-concrete composite T-beams, which have great application potential and ecological and economic value. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0023] Figure 1 This is one of the exploded schematic diagrams of a steel-bamboo-concrete composite T-beam according to an embodiment of the present invention;

[0024] Figure 2 This is the second exploded schematic diagram of a steel-bamboo-concrete composite T-beam in one embodiment of the present invention;

[0025] Figure 3 A schematic diagram of the steel-bamboo composite crossbeam in Figure 1;

[0026] Figure 4 This is a schematic diagram of the grooved shear key in Figure 1.

[0027] Figure 5 for Figure 1 Mid-span section diagram of the steel-bamboo-concrete composite T-beam;

[0028] Figure 6 for Figure 1Elevation view of the steel-bamboo-concrete composite T-beam.

[0029] Legend:

[0030] 100. Steel-bamboo-concrete composite T-beam; 10. UHPC precast bridge deck; 11. Precast deck; 20. Steel-bamboo composite beam frame; 21. Steel-bamboo composite precast T-beam; 211. Bamboo T-beam body; 212. Cold-formed thin-walled steel reinforcement; 213. Reception trough; 22. Steel-bamboo composite crossbeam; 221. Bamboo crossbeam; 222. Steel cladding; 23. Prestressed tendons; 24. Steel cladding at beam ends; 30. Shear connector; 31. Channel shear key; 32. Post-cast concrete structure.

[0031] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0032] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0035] Please refer to the appendix. Figure 1 , Figure 2 , Figure 3 , Figure 4 Figure 5 and Figure 6As shown, the steel-bamboo-concrete composite T-beam 100 provided by the present invention includes a UHPC precast bridge deck 10, a steel-bamboo composite beam frame 20, and shear connectors 30. The UHPC precast bridge deck 10 is erected on the steel-bamboo composite beam frame 20 and positioned by the shear connectors 30. The steel-bamboo composite beam frame 20 includes steel-bamboo composite precast T-beams 21, steel-bamboo composite transverse diaphragms 22, and prestressed tendons 23. Multiple steel-bamboo composite precast T-beams 21 are arranged and glued in a transverse direction, and adjacent steel-bamboo composite precast T-beams 21 are fixedly connected by corresponding steel-bamboo composite transverse diaphragms 22. The steel-bamboo composite diaphragm 22 is located at the transverse connection position of the steel-bamboo composite precast T-beam 21 and is situated between two adjacent steel-bamboo composite precast T-beams 21 in the transverse direction. Both ends of the steel-bamboo composite diaphragm 22 are fixedly connected to the corresponding steel-bamboo composite precast T-beam 21. The prestressed tendons 23 are tensioned longitudinally at the bottom of the steel-bamboo composite precast T-beam 21. The UHPC precast bridge deck 10 is erected on the steel-bamboo composite precast T-beam 21. The first end of the shear connector 30 is connected to the steel-bamboo composite precast T-beam 21, and the second end of the shear connector 30 is connected to the UHPC precast bridge deck 10.

[0036] The steel-bamboo-concrete composite T-beam 100 provided by this invention includes a UHPC precast bridge deck 10, a steel-bamboo composite beam frame 20, and shear connectors 30. The UHPC precast bridge deck 10 is supported by the steel-bamboo composite beam frame 20. The UHPC precast bridge deck 10 is made of UHPC concrete with high tensile strength. The steel-bamboo composite beam frame 20 is made of bamboo and receives auxiliary support from the steel. Both bamboo and UHPC materials have high tensile and compressive strength. By using steel for auxiliary support, the bending stiffness of the bamboo is improved, overcoming the technical problem of relatively low bending stiffness when supported solely by bamboo. This solves the problems of large concrete consumption and short service life in existing concrete bridges. The technical problem of generating a large amount of construction waste after completion is addressed by adopting a structure of longitudinally integral segments and laterally segmented splicing of steel-bamboo composite precast T-beams 21. This structure utilizes UHPC precast bridge deck 10 and shear connectors 30 to position and connect the steel-bamboo composite precast T-beams 21. The UHPC precast bridge deck 10 further constrains the laterally arranged steel-bamboo composite precast T-beams 21. By combining UHPC material structure, bamboo structure, and steel structure, the overall structural weight is reduced compared to existing concrete bridges. Furthermore, the superior properties of various materials improve the strength, stiffness, and durability of the steel-bamboo-concrete composite T-beams 100, demonstrating significant application potential and ecological and economic value.

[0037] Understandably, by using steel-bamboo composite beams 20 to support the UHPC precast bridge deck 10, and by using shear connectors 30 to position the steel-bamboo composite precast T-beams 21, the connection of the steel-bamboo composite precast T-beams 21, which are bonded together and fixedly connected by steel-bamboo composite crossbeams 22, is more stable. The use of UHPC concrete with high tensile strength for the entire bridge deck effectively reduces the amount of cement and the self-weight of the beam, and effectively reduces the cracking problem of concrete bridge deck in the negative bending moment zone during the operation of the composite beam.

[0038] Understandably, the bamboo material in the steel-bamboo composite beam frame 20 is engineered bamboo (plywood, reconstituted bamboo). More preferably, the bamboo material in the steel-bamboo composite beam frame 20 of the present invention is reconstituted bamboo.

[0039] Understandably, in order to meet the stiffness required for the span of the steel-bamboo composite precast T-beam 21, FRP prestressing tendons 23 are tensioned at the bottom of the steel-bamboo composite precast T-beam 21.

[0040] Research has revealed that engineered bamboo (glued bamboo, reconstituted bamboo) overcomes the material defects and dimensional variability of round bamboo, improves upon the disadvantages of original bamboo such as anisotropy, uneven material, unstable performance, and poor durability, while retaining its advantages such as high strength, good rigidity, high toughness, and environmental friendliness. Its mechanical properties are more stable, providing support for the application of bamboo in large-span load-bearing engineering structures. It can effectively reduce pollution and carbon emissions in bridge construction during production, construction, and operation, and promote the synergistic realization of economic and ecological value. It can serve as a new breakthrough point for the transformation and iteration of the construction field.

[0041] Understandably, Ultra-High Performance Concrete (UHPC) is a high-performance structural material with advantages including: high strength, significantly exceeding that of traditional concrete, reaching over 200 MPa; excellent density, effectively preventing the penetration of water and air; excellent durability, resisting the effects of harsh environments such as those with chloride ions; excellent crack resistance, effectively preventing cracking and fracture; and good fluidity and plasticity, facilitating the construction of components of various shapes and sizes, with mechanical properties approaching those of steel structures after appropriate reinforcement. Furthermore, UHPC exhibits outstanding abrasion resistance, making it particularly suitable for the construction of long-span bridges and for use in highly abrasive and corrosive environments. Currently, UHPC has been applied in several practical projects, such as long-span pedestrian bridges, highway and railway bridges, and its application is expected to continue to increase in the future.

[0042] Understandably, in this invention, the steel-bamboo composite precast T-beam 21 and the steel-bamboo composite crossbeam 22 are prefabricated in the factory. The prestressed tendons 23 are tensioned after the steel-bamboo composite precast T-beam 21 is assembled on site and the steel-bamboo composite crossbeam 22 is reinforced and connected, thus ensuring the stress of the structure. Subsequently, the UHPC precast bridge deck 10 and shear connector 30 are assembled to facilitate construction.

[0043] Understandably, the steel structure in the steel-bamboo composite beam frame 20 adopts a cold-formed thin-walled steel structure. The cold-formed thin-walled steel structure is a structure made of various cold-formed steels. The cold-formed thin-walled steels are formed by cold working (cold bending, cold pressing or cold drawing) of steel plates or strips with a thickness of 1.5 to 6 mm.

[0044] Furthermore, the steel-bamboo composite precast T-beam 21 includes a bamboo T-beam body 211 and a cold-formed thin-walled steel reinforcement 212. The flange sidewalls of two adjacent bamboo T-beam bodies 211 are glued together. The prestressed tendons 23 are tensioned longitudinally at the bottom of the bamboo T-beam body 211. The cold-formed thin-walled steel reinforcement 212 is located at the reinforcement position of the bamboo T-beam body 211. The cold-formed thin-walled steel reinforcement 212 is wrapped around the bamboo T-beam body 211 and is fixedly connected to the bamboo T-beam body 211. Understandably, the bamboo T-beam 211 is made of reconstituted bamboo. The bamboo T-beam 211 includes vertically arranged vertical beams and horizontal beams. The horizontal beams are supported on the vertical beams, and the vertical beams are positioned at the mid-section of the horizontal beams. Two horizontally adjacent bamboo T-beams 211 are glued together via the sidewalls of the horizontal beams and then fixedly connected by a steel-bamboo composite crossbeam 22. The two ends of the steel-bamboo composite crossbeam 22 are fixedly connected to the corresponding vertical beams. Cold-formed thin-walled steel reinforcements 212 are fixedly installed on the outer wall of the vertical beams, or fixedly installed on the bottom surface of the horizontal beams and between the vertical and horizontal beams, to improve the bending stiffness of the bamboo T-beam 211. Prestressing holes are provided at the bottom of the vertical beams, and prestressing tendons 23 are inserted through these holes.

[0045] Optionally, in this invention, the cold-formed thin-walled steel reinforcement 212 is fixedly connected to the bamboo T-beam 211. This connection can be achieved by gluing (adhesive bonding) or by further bolting after gluing, in order to improve the stability of the cold-formed thin-walled steel reinforcement 212 attached to the bamboo T-beam 211.

[0046] Research has revealed that both engineered bamboo and UHPC materials possess high tensile and compressive strength; however, bamboo exhibits relatively low bending stiffness. To overcome this disadvantage, this invention utilizes cold-formed thin-walled steel structures to increase the structural bending stiffness. By combining bamboo and UHPC materials, the high compressive strength of UHPC and the high tensile strength of bamboo are fully utilized. With the assistance of the cold-formed thin-walled steel structure, a thinner, lighter, and more economical composite structure is designed. In practical engineering, to ensure effective bonding between UHPC and bamboo, PBL shear keys and other connection methods are commonly used. However, this method requires grooving and reinforcing the bamboo, potentially damaging the original local texture of the bamboo. By incorporating cold-formed thin-walled steel reinforcement 212, the strength, stiffness, and stability of the composite structure are ensured.

[0047] Furthermore, to ensure the load-bearing performance of the structure, the cold-formed thin-walled steel reinforcement 212 includes an outer beam rib cold-formed thin-walled steel section located at the beam rib position of the bamboo T-beam 211, an outer horseshoe cold-formed thin-walled steel section located at the horseshoe position of the bamboo T-beam 211, and an outer flange cold-formed thin-walled steel section located at the flange position of the bamboo T-beam 211. The outer flange cold-formed thin-walled steel section, the outer beam rib cold-formed thin-walled steel section, and the outer horseshoe cold-formed thin-walled steel section are integrally formed and fixedly connected to the bamboo T-beam 211. In this invention, the outer flange cold-formed thin-walled steel section, the outer beam rib cold-formed thin-walled steel section, and the outer horseshoe cold-formed thin-walled steel section are integrally formed and glued to the bamboo T-beam 211 respectively, and then fixed by bolting.

[0048] Specifically, in order to further enhance the bending resistance and load-bearing capacity of the steel-bamboo composite beam frame 20, cold-formed thin-walled steel reinforcement members 212 are provided on the beam ribs (upper middle part of the vertical beam), a part of the horseshoe (bottom of the vertical beam), and the bottom of a part of the upper flange (horizontal beam) of the bamboo T-beam body 211. The cold-formed thin-walled steel reinforcement members 212 are mainly bonded to the bamboo T-beam body 211 with adhesive, and bolts or spot welding can be used to strengthen the connection where necessary.

[0049] Furthermore, the steel-bamboo composite precast T-beam 21 also includes end-coating steel 24 located at both longitudinal ends of the bamboo T-beam body 211, and the end-coating steel 24 is fixedly connected to the ends of the bamboo T-beam body 211. In this invention, to prevent erosion of the steel-bamboo composite precast T-beam 21 caused by bridge deck seepage due to damage to the expansion joint, end-coating steel 24 is provided at the ends of the bamboo T-beam body 211.

[0050] Even better, because the bamboo beams are located at expansion joints, damage to these joints can easily lead to water leakage and erosion of the beam structure. Please refer to this again. Figure 1 In this invention, the top of the beam end outer steel 24 is set to cover the flange plate and the top plate of the T-beam from the beam end, wherein the beam end outer steel 24 is made of thin-walled steel.

[0051] Optionally, the steel cladding 24 at the beam end is connected to the bamboo T-beam body 211 by adhesive bonding and / or bolting.

[0052] More preferably, the outer steel cladding 24 at the beam end covers the ends of the bamboo T-beam 211 from the bottom surface and both sides. The thickness of the bottom surface of the outer steel cladding 24 is greater than the thickness of the sides, which meets the requirements of local bearing pressure when the support is installed in the later stage of construction.

[0053] More preferably, the outer flange cold-formed thin-walled steel, the outer beam rib cold-formed thin-walled steel, the outer horseshoe cold-formed thin-walled steel, and the beam end outer wrapping steel are integrally formed.

[0054] Furthermore, the top surface of the bamboo T-beam 211 is recessed with a receiving groove 213, which is located at the transverse mid-section of the bamboo T-beam 211. The receiving groove is a trapezoidal groove with the groove diameter decreasing from top to bottom. The UHPC precast bridge deck 10 has a pre-reserved casting hole. The shear connector 30 includes a grooved shear key 31 and a post-cast concrete structure 32. The grooved shear key 31 is embedded in the receiving groove 213. Shear nails are arranged in the shear groove of the grooved shear key 31. The shear nails extend outward and protrude to the top surface of the bamboo T-beam 211. The UHPC precast bridge deck 10 is erected on the bamboo T-beam 211, and the casting hole and the shear groove are combined to form a casting groove. UHPC concrete is then poured into the casting groove to form the post-cast concrete structure 32. By setting a slotted shear key 31 (first end) for positioning shear keys in the top receiving groove 213 of the bamboo T-beam 211, and the shear nails of the positioning shear key and the post-cast concrete structure 32 (second end) passing through the receiving groove 213, the UHPC precast bridge deck 10 is positioned and assembled on the top surface of the bamboo T-beam 211, reducing the slippage of the UHPC precast bridge deck 10.

[0055] Furthermore, the grooved shear key 31 gradually tapers from top to bottom and is adapted to the receiving groove 213. The grooved shear key 31 is inserted into the receiving groove 213 and fixed by gluing and / or bolting.

[0056] Furthermore, the outer wall surface of the grooved shear key 31 is bonded to the groove wall surface of the receiving groove 213, and the bottom surface of the grooved shear key 31 is fixedly connected to the bottom of the receiving groove 213 by a connecting bolt.

[0057] More preferably, in order to better coordinate the stress of the steel-bamboo composite precast T-beam 21 and the UHPC precast bridge deck 10, and to facilitate the installation of shear connectors 30, a receiving groove 213 is reserved every 2m in the longitudinal direction of the middle of each bamboo T-beam 211.

[0058] In this invention, to enhance the coordinated stress distribution between the T-beam and the UHPC bridge deck, a shear connector 30 is specifically designed. The shear connector 30 includes a channel-shaped shear member and a post-cast concrete structure 32 formed by cast-in-place concrete. Four high-strength bolts connected to the T-beam are arranged inside the channel-shaped shear member. The high-strength bolts are used to extend into the T-beam. The four shear studs are welded in a quincunx pattern to the lower part of the channel-shaped shear member and placed in the shear groove. After the UHPC bridge deck is laid, a tenon is formed to make the connection between the bridge deck and the T-beam stronger and more coordinated. In this invention, the steel plates around the channel-shaped shear member are inclined inward at 45 degrees to reduce the shear forces it experiences in the transverse and longitudinal directions.

[0059] Furthermore, the exterior of the steel-bamboo composite precast T-beam 21 is coated with an anti-corrosion layer. A green, durable, anti-corrosion and anti-mildew phenolic resin is applied to the entire bamboo T-beam 211, especially to the parts not encased in cold-formed thin-walled steel, to enhance anti-corrosion and anti-mildew treatment. Fire protection design considers both fire-resistant calculations and fire-resistant construction to ensure the fire safety of the bamboo structure in the project.

[0060] Furthermore, the steel-bamboo composite crossbeam 22 includes a bamboo crossbeam 221, steel side panels 222, connecting screws, and connecting bolts. Two steel side panels 222 are disposed opposite each other at the transverse ends of the bamboo crossbeam 221. The steel side panels 222 are inserted into the transverse end edges of the corresponding bamboo crossbeam 221 through lateral openings. The steel side panels 222 are glued to the bamboo crossbeam 221. The connecting screws pass through the steel side panels 222 and extend into the bamboo crossbeam 221. The steel side panels 222 protrude from the wall surface of the bamboo crossbeam 221 and are provided with connecting holes. The connecting bolts pass through the connecting holes and are fixedly connected to the bamboo T-beam body 211.

[0061] In this invention, in specific implementation, the connecting screw passes through the connecting hole and connects to the cold-formed thin-walled steel reinforcement 212 of the bamboo T-beam 211. In order to improve the stability of the connection, the steel cladding 222 is further connected to the cold-formed thin-walled steel reinforcement 212 by electric welding on the basis of bolting.

[0062] Please refer to Figure 4 Furthermore, the steel enclosure 222 includes a top bending section, a vertical extension section, and a bottom bending section connected in sequence. The top bending section, the vertical extension section, and the bottom bending section are integrally formed, and the top bending section and the vertical extension section are respectively provided with connecting holes. It can be understood that the steel enclosure 222 in this invention is adapted to the cross-sectional shape of the T-beam so that the steel enclosure 222 and the T-beam are in surface contact and connected.

[0063] Furthermore, the UHPC precast bridge deck 10 includes precast panels 11, with multiple precast panels 11 arranged longitudinally and spliced ​​together via joints. In this invention, the joints can be either dry or wet joints. Furthermore, the joints and the steel-bamboo composite crossbeam 22 are located on the same cross section, minimizing disturbance to the steel-bamboo composite beam frame 20 during the longitudinal splicing of multiple precast panels 11. In this invention, the precast panels 11 are provided with casting holes, and the casting holes, shear connectors 30 (shear grooves), and receiving grooves 213 are arranged in a one-to-one correspondence.

[0064] The steel-bamboo-concrete composite T-beam 100 of the present invention has the following beneficial effects:

[0065] By fully leveraging the high strength properties of engineered bamboo, thin-walled steel, and UHPC concrete, and through the rational combination of these three materials, the strengths of each are maximized while mitigating their weaknesses. This approach, which fully utilizes the high strength properties of reconstituted bamboo, thin-walled steel, and UHPC concrete, while also adhering to the advanced prefabricated construction concept of "green building," will greatly enhance the selection space and application potential of composite structure bridges in bridge applications, demonstrating broad prospects.

[0066] By setting up a precast steel-bamboo composite T-beam 21 combining thin-walled steel and engineered bamboo, and fixing the cold-formed thin-walled steel reinforcement 212 to the wall surface of the bamboo T-beam 211 (by gluing or gluing and bolting), the structural strength is guaranteed. By setting up a precast steel-bamboo composite transverse beam 22 combining thin-walled steel and engineered bamboo, and fixing the steel cladding 222 to the end face of the bamboo beam 221 (by gluing or gluing and bolting), the steel cladding 222 protrudes from the wall surface of the main beam and has connection holes. The steel cladding 222 and the bamboo T-beam 211 are connected by gluing, bolting, welding and other fixing methods, which helps to ensure the structural strength while facilitating the assembly of precast components.

[0067] The 100-meter composite steel-bamboo-concrete T-beam structure ingeniously combines bamboo, steel, and concrete structures. Bamboo possesses excellent tensile properties, with a tensile strength exceeding 70 MPa. Particularly noteworthy is the parallel tensile strength of reconstituted bamboo, which can reach 129.17 MPa, more than ten times that of ordinary concrete. Under the same stress conditions, bamboo is significantly lighter than concrete, but its compressive strength is not ideal. The introduction of UHPC concrete and steel structures addresses this issue.

[0068] The present invention also provides a method for constructing a steel-bamboo-concrete composite T-beam 100, which includes the following steps:

[0069] On-site construction of steel-bamboo composite beam frame 20 involves splicing multiple steel-bamboo composite precast T-beams 21 with cold-formed thin-walled steel reinforcement members 212 laterally, bonding the flange sidewalls of adjacent steel-bamboo composite precast T-beams 21; fixing adjacent steel-bamboo composite precast T-beams 21 together with steel-bamboo composite transverse beams 22; and tensioning the prestressing tendons 23 of each steel-bamboo composite precast T-beam 21.

[0070] The grooved shear key 31 of the shear connector 30 is installed. The grooved shear key 31 is arranged in the receiving groove 213 on the top surface of the bamboo T-beam 211, so that the outer wall of the grooved shear key 31 is bonded to the groove wall of the receiving groove 213, so that the connecting bolt is inserted into the bottom surface of the receiving groove 213, and so that the shear nail extends to the top surface of the bamboo T-beam 211.

[0071] Precast panels 11 are laid longitudinally, so that the casting holes of the precast panels and the shear grooves of the grooved shear keys are combined to form a casting groove. UHPC concrete is then poured into the casting groove to form a post-cast concrete structure 32 for installing shear connectors 30, so that adjacent precast panels 11 are connected by splicing joints.

[0072] 23. Secondary tensioning of prestressed tendons.

[0073] Understandably, in this invention, the grooved shear key 31 can be arranged in the receiving groove 213 before the steel-bamboo composite prefabricated T-beam 21 is spliced, or the grooved shear key 31 can be arranged in the receiving groove 213 after the steel-bamboo composite prefabricated T-beam 21 is spliced.

[0074] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A steel-bamboo-concrete composite T-beam, characterized in that, The bridge includes UHPC precast bridge decks, steel-bamboo composite beams, and shear connectors. The UHPC precast bridge decks are erected on the steel-bamboo composite beams and positioned by the shear connectors. The steel-bamboo composite beam frame includes precast steel-bamboo T-beams, steel-bamboo composite transverse diaphragms, and prestressing tendons. Multiple precast steel-bamboo T-beams are sequentially arranged and glued together transversely. Laterally adjacent precast steel-bamboo T-beams are fixedly connected by corresponding steel-bamboo composite transverse diaphragms. The transverse diaphragms are located at the transverse connection points of the precast steel-bamboo T-beams and are situated between two laterally adjacent precast steel-bamboo T-beams. Both ends of the transverse diaphragms are fixedly connected to their respective precast steel-bamboo T-beams. The prestressing tendons are longitudinally tensioned at the bottom of the precast steel-bamboo T-beams. The steel-bamboo composite precast T-beam includes a bamboo T-beam body and cold-formed thin-walled steel reinforcements. Two adjacent bamboo T-beam bodies are bonded together along their transverse flange sidewalls. Prestressed tendons are longitudinally tensioned at the bottom of the bamboo T-beam body. The cold-formed thin-walled steel reinforcements are located at the reinforcement positions of the bamboo T-beam body and enclose the bamboo T-beam body. The cold-formed thin-walled steel reinforcements are fixedly connected to the bamboo T-beam body. The bamboo T-beam body includes vertically arranged vertical beams and horizontal beams. The horizontal beams are supported on the vertical beams, and the vertical beams are located at the mid-section of the horizontal beams. The UHPC precast bridge deck is erected on the steel-bamboo composite precast T-beam. The first end of the shear connector is connected to the steel-bamboo composite precast T-beam, and the second end of the shear connector is connected to the UHPC precast bridge deck.

2. The steel-bamboo-concrete composite T-beam according to claim 1, characterized in that, The cold-formed thin-walled steel reinforcement includes an outer beam rib cold-formed thin-walled steel section located at the beam rib position of the bamboo T-beam, an outer horseshoe cold-formed thin-walled steel section located at the horseshoe position of the bamboo T-beam, and an outer flange cold-formed thin-walled steel section located at the flange position of the bamboo T-beam. The outer flange cold-formed thin-walled steel section, the outer beam rib cold-formed thin-walled steel section, and the outer horseshoe cold-formed thin-walled steel section are integrally formed and fixedly connected to the bamboo T-beam.

3. The steel-bamboo-concrete composite T-beam according to claim 1, characterized in that, The steel-bamboo composite precast T-beam also includes beam end steel at both longitudinal ends of the bamboo T-beam body, and the beam end steel is fixedly connected to the end of the bamboo T-beam body.

4. The steel-bamboo-concrete composite T-beam according to any one of claims 1 to 3, characterized in that, The top surface of the bamboo T-beam is recessed with a receiving groove, which is located at the mid-section of the transverse section of the bamboo T-beam. The receiving groove is a trapezoidal groove with the diameter decreasing from top to bottom. The UHPC precast bridge deck has pre-drilled casting holes. The shear connector includes a grooved shear key and a post-cast concrete structure. The grooved shear key is embedded in the receiving groove, and shear studs are arranged in the shear groove of the grooved shear key. The shear studs extend outward and protrude to the top surface of the bamboo T-beam. The UHPC precast bridge deck is erected on the bamboo T-beam body, and the casting molding hole and the shear groove are combined to form a casting groove. UHPC concrete is then poured into the casting groove to form the post-cast concrete structure.

5. A steel-bamboo-concrete composite T-beam according to claim 4, characterized in that, The outer wall of the grooved shear key is bonded to the groove wall of the receiving groove, and the bottom surface of the grooved shear key is fixedly connected to the bottom of the receiving groove by a connecting bolt. The shear connector is a grooved shear connector with the second end gradually narrowing from the top to the bottom.

6. The steel-bamboo-concrete composite T-beam according to any one of claims 1 to 3, characterized in that, The outer perimeter of the steel-bamboo composite precast T-beam is coated with an anti-corrosion layer.

7. A steel-bamboo-concrete composite T-beam according to any one of claims 1 to 3, characterized in that, The steel-bamboo composite crossbeam includes a bamboo crossbeam, steel panels, connecting screws, and connecting bolts. Two steel panels are positioned opposite each other at the transverse ends of the bamboo crossbeam. The steel panels are inserted into the transverse end edges of the corresponding bamboo crossbeam through lateral openings. The steel panels are glued to the bamboo crossbeam. The connecting screws pass through the steel panels and extend into the bamboo crossbeam. The steel panels protrude from the wall of the bamboo crossbeam and have connecting holes. The connecting bolts pass through the connecting holes and are fixedly connected to the bamboo T-beam body.

8. The steel-bamboo-concrete composite T-beam according to any one of claims 1 to 3, characterized in that, The UHPC prefabricated bridge panel includes prefabricated panels, and multiple prefabricated panels are arranged longitudinally and spliced ​​together by splicing seams.

9. A method for constructing a steel-bamboo-concrete composite T-beam, characterized in that, The method for constructing the steel-bamboo-concrete composite T-beam as described in any one of claims 1 to 8 includes the following steps: On-site construction of steel-bamboo composite beam frame involves splicing multiple precast steel-bamboo composite T-beams with cold-formed thin-walled steel reinforcements laterally, bonding the flange sidewalls of adjacent precast steel-bamboo composite T-beams together; fixing adjacent precast steel-bamboo composite T-beams together with steel-bamboo composite crossbeams; and tensioning the prestressing tendons of each precast steel-bamboo composite T-beam. The grooved shear key for installing the shear connector is arranged in the corresponding groove on the top surface of the bamboo T-beam, so that the outer wall of the grooved shear key is bonded to the groove wall of the groove, the connecting bolt is inserted into the bottom surface of the groove, and the shear nail extends to the top surface of the bamboo T-beam. Precast panels are laid longitudinally, so that the casting holes of the precast panels and the shear grooves of the grooved shear keys are combined to form a casting groove. The casting holes, shear grooves and receiving grooves are arranged in a one-to-one correspondence. UHPC concrete is then poured into the casting groove to form a post-cast concrete structure for installing shear connectors, so that adjacent precast panels along the longitudinal direction are connected by splicing joints. The prestressed tendons are tensioned in a secondary manner.

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