A fully wrapped concrete truss structure and method of construction thereof

Abstract

The application discloses a full-wrapping concrete truss structure and a construction method thereof, and belongs to the technical field of building structures. The full-wrapping concrete truss structure comprises a steel pipe truss assembly arranged between a plurality of steel plates, a wrapping assembly arranged outside the steel pipe truss assembly, and a concrete layer arranged outside the wrapping assembly. The construction method comprises the following steps: S1, preparing a top chord, a bottom chord, a vertical rod and a horizontal rod, wrapping the rods with a reinforcing mesh and welding to obtain a steel pipe truss shell; S2, arranging a diagonal web member assembly inside the shell and arranging a connecting mesh outside the shell to form a steel pipe truss monomer; S3, bolt connecting a plurality of monomers and bolt connecting the steel plates and the monomers at edges to form a steel pipe truss structure; and S4, vibrating the steel pipe truss structure after concrete partition pouring to obtain the full-wrapping concrete truss structure. The application can realize full wrapping of the steel pipe, ensure that the concrete layer is tightly bonded with the steel pipe, and improve the stability and safety of the structure.

Description

Technical Field

[0001] This invention relates to the field of reinforced concrete technology, and in particular to a fully enclosed concrete truss structure and its construction method. Background Technology

[0002] With the development of science and technology and the needs of engineering construction, the requirements for building materials are becoming increasingly stringent. Concrete, as a traditional building material, is widely used in various structures due to its excellent mechanical properties and durability. Truss structures are a common type of building structure, composed of many straight members connected together at joints.

[0003] Although truss structures have many advantages, such as simple structure, high load-bearing capacity, and good stability, they also have some disadvantages. Since the members of a truss structure mainly bear axial tensile and compressive stress, their lateral stiffness is relatively small and they are prone to lateral deformation. At the same time, the members of a truss structure are generally made of materials such as square steel pipes or reinforced concrete, so their load-bearing capacity and durability are limited by the materials.

[0004] When steel pipe trusses are used in combination with concrete, the cross-section of the steel pipes will decrease under pressure. At the same time, existing technologies cannot achieve full encapsulation of steel pipe trusses with concrete. During the hardening process, concrete undergoes water evaporation and chemical reactions, which makes it difficult to control the volume shrinkage and deformation of the concrete. Furthermore, the shrinkage rate of different parts of the concrete may be uneven, resulting in micro-cracks and voids inside. Under stress, the concrete cannot work together with the steel pipe, which will lead to uneven stress on the steel pipe or premature local failure. Summary of the Invention

[0005] This invention overcomes the shortcomings of the prior art and provides a fully enclosed concrete truss structure and its construction method.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a fully enclosed concrete truss structure, comprising: a plurality of steel plates, a steel pipe truss assembly disposed between the plurality of steel plates, an enclosing assembly disposed outside the steel pipe truss assembly, and a concrete layer disposed outside the enclosing assembly, characterized in that,

[0007] The steel pipe truss assembly is composed of several steel pipe truss units connected together. Each steel pipe truss unit includes: several upper chords, several lower chords arranged opposite to the upper chords, vertical members for connecting the upper chords and the lower chords, and several diagonal web member assemblies arranged between the upper chords and the lower chords; the diagonal web member assemblies are connected to fixed member assemblies; and horizontal members are provided between the several upper chords and the several lower chords.

[0008] Each of the above upper chords and the above vertical bars is provided with an upper node, and each of the above lower chords and the above vertical bars is provided with a lower node;

[0009] The diagonal brace assembly includes: a first upper diagonal brace and a second upper diagonal brace connected to the upper node, and a first lower diagonal brace and a second lower diagonal brace connected to the lower node;

[0010] The wrapping assembly includes: an upper wrapping net disposed outside the first upper inclined web member and the second upper inclined web member, a lower wrapping net disposed outside the first lower inclined web member and the second lower inclined web member, a first reinforcing net disposed outside the upper chord member and the lower chord member, and a second reinforcing net disposed outside the vertical member and the horizontal member.

[0011] In a preferred embodiment of the present invention, the fixing rod assembly includes: a side fixing rod connected to the first upper inclined web member and the first lower inclined web member, an upper fixing rod connected to the second upper inclined web member, and a lower fixing rod connected to the second lower inclined web member.

[0012] In a preferred embodiment of the present invention, the lengths of the upper chord, the lower chord, the vertical bar, and the horizontal bar are equal; the lengths of the first upper diagonal brace, the second upper diagonal brace, the first lower diagonal brace, and the second lower diagonal brace are equal.

[0013] In a preferred embodiment of the present invention, the length relationship between the first upper inclined web member and the upper chord member is as follows: Where S is the length of the upper chord and L is the length of the first upper diagonal web member.

[0014] In a preferred embodiment of the present invention, the first upper inclined web member is inclined from the upper node toward the interior of the steel pipe truss assembly, the first lower inclined web member is inclined from the lower node toward the interior of the steel pipe truss assembly, the angles with the vertical members are all 35° to 40°, the angles with the upper chord members are all 45° to 50°, and the angles with the horizontal members are all 45° to 50°.

[0015] In a preferred embodiment of the present invention, the inclination direction of the second upper inclined web member is from the upper node to the interior of the steel pipe truss assembly, and the inclination direction of the second lower inclined web member is from the lower node to the interior of the steel pipe truss assembly. The angles with the vertical members are both 50° to 55°, the angles with the upper chord members are both 35° to 40°, and the angles with the horizontal members are both 35° to 40°.

[0016] In a preferred embodiment of the present invention, both the upper wrapping net and the lower wrapping net are glass fiber nets with a pore size of 10-20 mm, the fiber mesh holes are diamond-shaped, and the fiber diameter is 2-3 mm.

[0017] In a preferred embodiment of the present invention, both the first reinforcing mesh and the second reinforcing mesh are high-strength glass fiber meshes with a pore size of 5-10 mm, square pores, and fiber diameters of 4-4.5 mm.

[0018] The present invention also provides a construction method for a fully enclosed concrete truss structure, characterized by comprising the following steps:

[0019] S1. Prepare the upper chord, lower chord, vertical members and horizontal members, wrap them with reinforcing mesh and weld them into a three-dimensional structure, and set nodes at the intersection points to obtain the steel pipe truss shell;

[0020] S2. Diagonal web members are installed inside the steel pipe truss shell. A wrapping net is installed on the outside of the diagonal web members and a fixing rod assembly is welded on. After a connecting net is installed on the outside of the steel pipe truss shell, a single steel pipe truss unit is formed.

[0021] S3. Several steel pipe truss units are bolted together, and several steel plates are bolted together with the steel pipe truss units at the edge to form a steel pipe truss structure.

[0022] S4. Apply adhesive to the surfaces of the reinforcing mesh, wrapping mesh, and connecting mesh. Pour concrete into sections for the steel pipe truss structure. During the pouring process, continuously grout to remove gaps. After pouring, vibrate with a vibrating plate. After the concrete has initially solidified, remove the formwork and trim the surface to obtain a fully wrapped concrete truss structure.

[0023] In a preferred embodiment of the present invention, in S4, the adhesive used is one of epoxy resin adhesive, polyurethane adhesive and acrylate adhesive.

[0024] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0025] (1) The present invention provides a fully enclosed concrete truss structure and its construction method. By adding a glass fiber mesh to the outside of the steel pipe and pouring concrete to form a "steel pipe-glass fiber mesh-concrete" structure, the steel pipe can be fully enclosed. The glass fiber mesh can withstand the shrinkage deformation of the concrete, prevent the generation of cracks and voids, and ensure that the concrete layer is tightly bonded to the steel pipe, thereby ensuring that the characteristics of the fully enclosed steel pipe are fully utilized and improving the stability and safety of the structure.

[0026] (2) The present invention provides a steel pipe truss assembly, which is made of multiple steel pipes connected together. It has high structural strength, excellent load-bearing capacity and stability. It can provide strong support for the overall structure and ensure the stability of the overall structure. The design of this assembly makes the cross-section of the steel pipe increase when subjected to pressure, instead of decreasing like ordinary steel. This characteristic enables the steel pipe to generate greater load-bearing capacity and energy absorption capacity when subjected to force. It can be optimized according to the stress requirements, making the use of materials more efficient and thus reducing costs.

[0027] (3) The present invention is equipped with a wrapping component, which uses a variety of fiber meshes to wrap the steel pipe, which can effectively fix the diagonal web member component and the concrete layer, and can withstand the shrinkage deformation of the concrete. This solves the problem of micro-cracks and voids in the prior art caused by uneven shrinkage rates in different parts of the concrete, and prevents the generation of cracks and voids.

[0028] (4) The present invention has a connecting net between the vertical and horizontal bars, which works in conjunction with the upper and lower wrapping nets and the reinforcing net to effectively limit the deformation of the concrete layer at the edge of the steel pipe truss unit, avoiding the problem of difficult control of concrete volume shrinkage deformation in the prior art, and ensuring the overall performance of the structure.

[0029] (5) The present invention constructs a steel pipe truss structure with compressive shrinkage characteristics by combining steel pipe truss components with diagonal web members. When subjected to external forces, the compressive shrinkage structure can automatically generate loads, allowing the structure to absorb more energy, thereby having excellent seismic performance. At the same time, after exceeding the elastic limit, it can undergo a larger range of plastic deformation without being destroyed, thus having stronger plastic seismic resistance. When the force is released, the compressive shrinkage structure can automatically return to its original state, and the overall performance will not decline due to small-scale damage, thus ensuring the stability of the overall performance.

[0030] (6) The present invention uses concrete to fill the cavity formed by the compressive shrinkage steel pipe truss to form a concrete core structure. When the structure is subjected to shear force, the steel pipe truss will elongate and deform, and absorb the tensile force by utilizing its compressive shrinkage characteristics. At the same time, the truss will elongate and deform to apply pressure to the surroundings. At this time, the concrete core uses its good compressibility to withstand the pressure. The steel pipe and the concrete core form a whole and work together to resist the tensile and compressive forces applied by the outside, thus achieving the best structural effect. Attached Figure Description

[0031] 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 recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is an overall three-dimensional structural diagram of a preferred embodiment of the present invention;

[0033] Figure 2 This is a three-dimensional structural diagram of a steel pipe truss unit according to a preferred embodiment of the present invention;

[0034] Figure 3 This is a connection diagram of a preferred embodiment of the present invention;

[0035] Figure 4 This is a flowchart of a preferred embodiment of the present invention;

[0036] In the diagram: 1. Steel plate; 2. Steel pipe truss assembly; 3. Single steel pipe truss unit; 31. Top chord; 32. Bottom chord; 33. Vertical member; 34. Diagonal web member assembly; 341. First upper diagonal web member; 342. Second upper diagonal web member; 343. First lower diagonal web member; 344. Second lower diagonal web member; 35. Fixing member assembly; 351. Side fixing member; 352. Upper fixing member; 353. Lower fixing member; 36. Horizontal member. Detailed Implementation

[0037] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0039] like Figure 1 As shown, a fully enclosed concrete truss structure includes: several steel plates 1, steel pipe truss components 2 disposed between the several steel plates 1, an enclosure component disposed outside the steel pipe truss components 2, and a concrete layer disposed outside the enclosure component; it should be noted that in specific implementation, the several steel pipe truss components can be fixed by welding to increase the length of the truss and expand the application range of the truss.

[0040] This structure, by adding a fiberglass mesh to the outside of the steel pipe and pouring concrete to form a "steel pipe-fiberglass mesh-concrete" structure, can achieve full encapsulation of the steel pipe. The fiberglass mesh can withstand the shrinkage and deformation of the concrete, prevent the formation of cracks and voids, and ensure that the concrete layer is tightly bonded to the steel pipe, thereby ensuring that the properties of the steel pipe are fully utilized and improving the stability and safety of the structure.

[0041] like Figure 2 As shown, the steel pipe truss assembly 2 is composed of several steel pipe truss units 3 connected together. Each steel pipe truss unit 3 includes: several upper chords 31, several lower chords 32 arranged opposite to the upper chords 31, vertical members 33 for connecting the upper chords 31 and the lower chords 32, and several diagonal web member assemblies 34 arranged between the upper chords 31 and the lower chords 32. The diagonal web member assemblies 34 are connected to fixed rod assemblies 35. The fixed rod assemblies 35 are connected to the steel plate 1 with high-strength bolts at the end away from the diagonal web member assemblies 34.

[0042] A crossbar is provided between several upper chord members 31 and several lower chord members 32. 36 An upper node is provided at the connection between several upper chord members 31 and several vertical members 33, and a lower node is provided at the connection between several lower chord members 32 and several vertical members 33.

[0043] The lengths of the upper chord 31, lower chord 32, vertical member 33, and horizontal member are equal; the lengths of the first upper diagonal web member 341, second upper diagonal web member 342, first lower diagonal web member 343, and second lower diagonal web member 344 are equal; the length relationship between the first upper diagonal web member 341 and the upper chord 31 is as follows: Where S is the length of the upper chord 31, L is the length of the first upper inclined web member 341, and the length of the upper chord 31 is in the range of 3m≤S≤9m.

[0044] The steel pipe truss component 2 is composed of multiple steel pipes connected together, resulting in high structural strength, excellent load-bearing capacity, and stability. It provides strong support for the overall structure, ensuring its stability. The design of this component allows the cross-section of the steel pipe to increase under pressure, rather than decreasing as in ordinary steel. This characteristic enables the steel pipe to generate greater load-bearing capacity and energy absorption capacity under stress. It can be optimized according to stress requirements, making the use of materials more efficient and thus reducing costs.

[0045] The diagonal brace assembly 34 includes: a first upper diagonal brace 341 and a second upper diagonal brace 342 connected to the upper node, and a first lower diagonal brace 343 and a second lower diagonal brace 344 connected to the lower node.

[0046] The steel pipe truss assembly 2, combined with the diagonal web member assembly 34, constitutes a fully enclosed steel pipe truss structure with compressive shrinkage characteristics. When subjected to external forces, the compressive shrinkage structure can automatically generate loads, allowing the structure to absorb more energy, thus exhibiting excellent seismic performance. Furthermore, after exceeding the elastic limit, it can undergo a wider range of plastic deformation without failure, demonstrating stronger plastic seismic resistance. When the force is released, the structure can automatically return to its original state, preventing a decline in overall performance due to minor damage and ensuring the stability of overall performance.

[0047] like Figure 3As shown, the fixing rod assembly 35 includes: a side fixing rod 351 connected to the first upper inclined web member 341 and the first lower inclined web member 343, an upper fixing rod 352 connected to the second upper inclined web member 342, and a lower fixing rod 353 connected to the second lower inclined web member 344.

[0048] Several first upper inclined web members 341 are connected at one end away from the upper node and several first lower inclined web members 343 are connected at one end away from the lower node. Several second upper inclined web members 342 are connected at one end away from the upper node and several second lower inclined web members 344 are connected at one end away from the lower node.

[0049] The first upper inclined web member 341 is inclined from the upper node to the inside of the steel pipe truss assembly 2, and the first lower inclined web member 343 is inclined from the lower node to the inside of the steel pipe truss assembly 2. The angles with the vertical member 33 are all 35° to 40°, the angles with the upper chord member 31 are all 45° to 50°, and the angles with the horizontal member are all 45° to 50°.

[0050] The second upper inclined web member 342 is inclined from the upper node to the inside of the steel pipe truss assembly 2, and the second lower inclined web member 344 is inclined from the lower node to the inside of the steel pipe truss assembly 2. The angles with the vertical member 33 are both 50° to 55°, the angles with the upper chord member 31 are both 35° to 40°, and the angles with the horizontal member are both 35° to 40°.

[0051] The wrapping assembly includes: an upper wrapping netting disposed outside the first upper inclined web member 341 and the second upper inclined web member 342, a lower wrapping netting disposed outside the first lower inclined web member 343 and the second lower inclined web member 344, a first reinforcing netting disposed outside the upper chord member 31 and the lower chord member 32, and a second reinforcing netting disposed outside the vertical member 33 and the horizontal member.

[0052] The wrapping component uses multiple fiber meshes to wrap the steel pipe, which can effectively fix the diagonal web member component 34 and the concrete layer. It can withstand the shrinkage deformation of the concrete and solves the problem of micro-cracks and voids caused by uneven shrinkage rates in different parts of the concrete in the existing technology, thus preventing the generation of cracks and voids.

[0053] Both the upper and lower wrapping nets are made of fiberglass mesh with a mesh size of 10–20 mm. The fiberglass mesh holes are diamond-shaped, and the fiber diameter is 2–3 mm. Both the first and second reinforcing nets are made of high-strength fiberglass mesh with a mesh size of 5–10 mm. The high-strength fiberglass mesh holes are square, and the fiber diameter is 4–4.5 mm.

[0054] A first connecting line is provided between the upper chord 31 and the lower chord 32, with both ends of the first connecting line wound around the upper chord 31 and the lower chord 32 respectively; a second connecting line is provided between several vertical bars 33, with both ends of the second connecting line wound around several parallel vertical bars 33 respectively; the first and second connecting lines are arranged alternately to form a connecting net; both the first and second connecting lines are made of high-elasticity modulus glass fiber with a fiber diameter of 1-2 mm, and the pore area of ​​the connecting net is 4.5-8 mm². 2 .

[0055] The connecting mesh, along with the upper and lower wrapping mesh and the reinforcing mesh, works together to effectively limit the deformation of the concrete layer at the edge of the steel pipe truss unit 3, avoiding the problem of uncontrollable concrete volume shrinkage deformation in existing technologies, and ensuring the overall performance of the structure.

[0056] like Figure 4 As shown, a construction method for a fully enclosed concrete truss structure is provided, characterized by the following steps:

[0057] S1. Prepare the upper chord 31, lower chord 32, vertical bar 33 and horizontal bar, wrap them with reinforcing mesh and weld them into a three-dimensional structure, and set nodes at the intersection points to obtain the steel pipe truss shell;

[0058] S2. Diagonal web member assembly 34 is set inside the steel pipe truss shell. A wrapping net is set outside the diagonal web member assembly 34 and a fixing rod assembly 35 is welded on. After the connecting net is set outside the steel pipe truss shell, a steel pipe truss unit 3 is formed.

[0059] S3. Several steel pipe truss units 3 are bolted together, and several steel plates 1 are bolted together with the steel pipe truss units 3 at the edge to form a steel pipe truss structure.

[0060] S4. Apply adhesive to the surfaces of the reinforcing mesh, wrapping mesh, and connecting mesh. Pour concrete into sections for the steel pipe truss structure. During the pouring process, continuously grout to remove gaps. After pouring, vibrate with a vibrating plate. After the concrete has initially solidified, remove the formwork and trim the surface to obtain a fully wrapped concrete truss structure.

[0061] In S1, the steel pipes used for the upper chord 31, lower chord 32, vertical bar 33 and horizontal bar have a diameter of Φ50mm-Φ65mm and a node diameter of 80-100mm. Each steel pipe is welded 360° around the circumference using an electric welding machine, and the weld strength must reach 90%-95% of the basic steel strength.

[0062] In S2, the length of the wrapping net is equal to the length of the corresponding steel pipe.

[0063] In S3, one of the following bolts is used: ISO 4014 bolt, DIN 6914 bolt, and ASTM A325 bolt.

[0064] In S4, the adhesive used is one of epoxy resin adhesive, polyurethane adhesive, and acrylic adhesive.

[0065] The cavity formed by the compressive shrinkage of the steel pipe truss is filled with concrete to form a concrete core structure. When the structure is subjected to shear force, the steel pipe truss will elongate and deform, absorbing the tensile force by utilizing its compressive shrinkage characteristics. At the same time, the truss will elongate and deform to apply pressure to the surroundings. At this time, the concrete core will withstand the pressure by utilizing its good compressibility. The steel pipe and the concrete core form a whole and work together to resist the tensile and compressive forces applied by the outside, achieving the best structural effect.

[0066] Example 1

[0067] A construction method for a fully enclosed concrete truss structure includes:

[0068] S1. Using a TL6016 tube laser cutting machine, prepare steel pipes with a diameter of Φ50mm, including upper chord, lower chord, vertical bar, and horizontal bar, according to the dimensions required by the design drawings, and ensure that the cut steel surface is flat and burr-free; the length of the upper chord, lower chord, vertical bar, and horizontal bar is 3m each;

[0069] The upper and lower chords are wrapped with a first reinforcing mesh, and the vertical and horizontal members are wrapped with a second reinforcing mesh. Both the first and second reinforcing meshes are high-strength fiberglass meshes with a pore size of 5mm, square mesh holes, and fiber diameter of 4mm. They are welded into a three-dimensional structure. At the intersection points of the upper chord, lower chord, vertical members, and horizontal members, 360° full-circumference welding is performed using an electric welding machine to form nodes with a node diameter of 80mm, thus obtaining the steel pipe truss shell.

[0070] S2. Determine that the lengths of the first upper inclined web member, the second upper inclined web member, the first lower inclined web member, and the second lower inclined web member are all 2m, and cut them using a TL6016 tube laser cutting machine. Place the cut inclined web member assembly into the predetermined position of the steel pipe truss shell. The inclination direction of the first upper inclined web member is from the upper node to the inside of the steel pipe truss assembly, and the inclination direction of the first lower inclined web member is from the lower node to the inside of the steel pipe truss assembly. The angles with the vertical members are all 35°, the angles with the upper chord members are all 45°, and the angles with the horizontal members are all 45°.

[0071] The second upper inclined web member is inclined from the upper node to the inside of the steel pipe truss assembly, and the second lower inclined web member is inclined from the lower node to the inside of the steel pipe truss assembly. The angles with the vertical member are both 55°, the angles with the upper chord member are both 35°, and the angle with the horizontal member is 40°. The accurate installation of the inclined web member assembly is ensured by using a total station.

[0072] Next, an upper wrapping net is installed outside the first and second upper inclined web members, and a lower wrapping net is installed outside the first and second lower inclined web members. Both the upper and lower wrapping nets are made of fiberglass mesh with a mesh size of 10mm, diamond-shaped holes, and fiber diameter of 2mm. The first upper inclined web member and the first lower inclined web member are welded to the side fixing rod using an electric welding machine, the second upper inclined web member is welded to the upper fixing rod, and the second lower inclined web member is welded to the lower fixing rod.

[0073] Then, a first connecting line with a fiber diameter of 1mm is installed between the upper and lower chords, and a second connecting line with a fiber diameter of 1mm is installed between the vertical members, forming a hole with an area of ​​4.5mm². 2 The connection network;

[0074] Diagonal web members are installed inside the steel pipe truss shell. All diagonal web members are wrapped with netting and fixed rods are welded to the outside. After connecting netting is installed outside the steel pipe truss shell, a single steel pipe truss unit is formed.

[0075] S3. Clean the joint surfaces of the steel pipe truss unit and the steel plate to ensure there are no oil stains, rust, or other impurities. Use hoisting equipment to place the first steel pipe truss unit in the predetermined position. Next, hoist the second unit and use a level to ensure its precise alignment with the first unit in both horizontal and vertical directions. Connect it with ISO 4014 bolts.

[0076] S4. Apply epoxy resin adhesive to the surfaces of the reinforcing mesh, wrapping mesh, and connecting mesh. Pour concrete into sections for the steel pipe truss structure. During the pouring process, continuously grout to remove voids. After pouring, vibrate with a ZW90-10 plate vibrator. After the concrete has initially solidified, remove the formwork and trim the surface to obtain a fully wrapped concrete truss structure with compressive shrinkage characteristics.

[0077] Example 2

[0078] The difference between this embodiment and Embodiment 1 is that in this embodiment, the lengths of the upper chord, lower chord, vertical bar, and horizontal bar are all 6m, and the lengths of the first upper inclined web bar, the second upper inclined web bar, the first lower inclined web bar, and the second lower inclined web bar are all 4m.

[0079] Example 3

[0080] The difference between this embodiment and Embodiment 1 is that in this embodiment, the lengths of the upper chord, lower chord, vertical bar, and horizontal bar are all 9m, and the lengths of the first upper inclined web bar, the second upper inclined web bar, the first lower inclined web bar, and the second lower inclined web bar are all 6m.

[0081] Example 4

[0082] The difference between this embodiment and Embodiment 1 is that, in this embodiment, the angles between the first upper inclined web member and the first lower inclined web member and the vertical member are both 40°, the angles between them and the upper chord member are both 50°, and the angles between them and the horizontal member are both 50°.

[0083] Example 5

[0084] The difference between this embodiment and Embodiment 1 is that, in this embodiment, the angles between the second upper inclined web member and the second lower inclined web member and the vertical member are both 50°, the angles between them and the upper chord member are both 40°, and the angles between them and the horizontal member are both 35°.

[0085] Comparative Example 1

[0086] The difference between this comparative example and Example 1 is that in this comparative example, only square steel tubes are used to prepare the truss.

[0087] Experimental Example 1

[0088] The following tests were performed on the steel tube truss structure samples prepared in Examples 1-5 and Comparative Example 1:

[0089] (1) Use the ww-06 ​​portable X-ray flaw detector to emit X-rays through the structure to be tested, use an image receiving device to receive the transmitted rays, generate an image of the internal structure, observe and analyze the processed image, check the interface between the concrete layer, steel pipe and fiber mesh, pay special attention to whether there are gaps, cracks or other defects, and summarize the flaw detection results in Table 1.

[0090] Table 1 Summary of flaw detection results for samples

[0091] experimental group Interface situation Are there any defects? Is it fully enclosed? Example 1 No clear boundaries, tightly bonded No cracks, no gaps yes Example 2 No clear boundaries, tightly bonded No cracks, no gaps yes Example 3 A boundary is created between the concrete layer and the steel pipe. Tiny cracks, no gaps no Example 4 No clear boundaries, tightly bonded No cracks, no gaps yes Example 5 A boundary is created between the concrete layer and the steel pipe. No cracks, tiny gaps no Comparative Example 1 A clear boundary is created between the concrete layer and the steel pipe. Multiple cracks, large gaps no

[0092] As shown in Table 1, the interfaces in Examples 1, 2, and 4 are all "without clear boundaries and tightly bonded," and none of them exhibit cracks or voids. This indicates that in these examples, the bond between the concrete layer and the steel pipe is very tight, with no obvious defects. Therefore, they are all considered to have achieved full encapsulation.

[0093] Both Examples 3 and 5 exhibited a boundary between the concrete layer and the steel pipe. Example 3 showed minor cracks but no voids, while Example 5, although free of cracks, showed minor voids. Therefore, both examples were considered incompletely encapsulated, as the presence of minor cracks and voids weakens the overall structural performance.

[0094] Finally, in Comparative Example 1, a clear boundary was observed between the concrete layer and the steel pipe, along with multiple cracks and large voids. This indicates that the bond between the concrete layer and the steel pipe in the comparative example was very poor, exhibiting significant defects. Therefore, it was considered that full encapsulation was not achieved.

[0095] (2) Using a 5KN universal testing machine, all samples were compressed to failure at a constant speed of 10mm / min. Three sets of experiments were repeated, and three samples were tested in each set. The stiffness was tested using the ISO-13314 standard, and the yield strength was determined using the 0.2% deformation displacement method. The data were summarized in Table 2.

[0096] Table 2 Summary of Mechanical Properties of Samples

[0097] experimental group Porosity (%) Stiffness (kPa) Yield strength (kPa) Example 1 1.2 273.13 23.57 Example 2 0.8 288.54 27,63 Example 3 3.2 249.45 19.58 Example 4 0.6 295.56 33.61 Example 5 7.1 213.37 15.75 Comparative Example 1 32.5 156.81 5.63

[0098] As shown in Table 2, the porosity of Examples 1 to 5 is in a relatively low range, ranging from 0.6% to 7.1%, indicating that the bond between the concrete layer and the steel pipe is relatively tight, and the fiberglass mesh effectively withstands the shrinkage deformation of the concrete, preventing the generation of cracks and voids.

[0099] Furthermore, in Examples 1 to 5, the stiffness values ​​were relatively high, ranging from 213.37 kPa to 295.56 kPa. This indicates that the "steel pipe-fiberglass mesh-concrete" structure can maintain good stability and has a strong resistance to deformation under stress.

[0100] In terms of yield strength, the values ​​of Examples 1 to 5 are also relatively high, ranging from 15.75 kPa to 33.61 kPa, indicating that the structure can withstand greater forces when subjected to pressure and can maintain good elastic deformation before reaching the yield point.

[0101] However, Comparative Example 1 showed a porosity as high as 32.5%, which far exceeded the porosity in the examples. The stiffness and yield strength of Comparative Example 1 were also significantly lower, at 156.81 kPa and 5.63 kPa, respectively. This indicates that excessively high porosity significantly affects the mechanical properties of the structure, greatly reducing its stability and safety.

[0102] In conclusion, the following conclusions can be drawn:

[0103] The "steel pipe-fiberglass mesh-concrete" structure, formed by adding fiberglass mesh to the outside of the steel pipe and pouring concrete, can maintain good mechanical properties, including high stiffness and yield strength, even with low porosity. The fiberglass mesh plays an important role in the structure, able to withstand the shrinkage deformation of the concrete, prevent the formation of cracks and voids, and ensure a tight bond between the concrete layer and the steel pipe.

[0104] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A fully enclosed concrete truss structure, comprising: A plurality of steel plates (1), a steel pipe truss assembly (2) disposed between the plurality of steel plates (1), a wrapping assembly disposed outside the steel pipe truss assembly (2), and a concrete layer disposed outside the wrapping assembly, characterized in that, The steel pipe truss assembly (2) is formed by connecting several steel pipe truss units (3). Each steel pipe truss unit (3) includes: several upper chords (31), several lower chords (32) arranged opposite to the upper chords (31), vertical members (33) for connecting the upper chords (31) and the lower chords (32), and several diagonal web member assemblies (34) arranged between the upper chords (31) and the lower chords (32); the diagonal web member assemblies (34) are connected to fixed member assemblies (35); and horizontal members (36) are provided between the several upper chords (31) and the several lower chords (32). An upper node is provided at the connection between several upper chords (31) and several vertical bars (33), and a lower node is provided at the connection between several lower chords (32) and several vertical bars (33); The diagonal brace assembly (34) includes: a first upper diagonal brace (341) and a second upper diagonal brace (342) connected to the upper node, and a first lower diagonal brace (343) and a second lower diagonal brace (344) connected to the lower node; The wrapping assembly includes: an upper wrapping net disposed outside the first upper inclined web member (341) and the second upper inclined web member (342); a lower wrapping net disposed outside the first lower inclined web member (343) and the second lower inclined web member (344); a first reinforcing net disposed outside the upper chord member (31) and the lower chord member (32); and a second reinforcing net disposed outside the vertical member (33) and the horizontal member (36). The fixing rod assembly (35) includes: a side fixing rod (351) connected to the first upper inclined web member (341) and the first lower inclined web member (343), an upper fixing rod (352) connected to the second upper inclined web member (342), and a lower fixing rod (353) connected to the second lower inclined web member (344).

2. The fully enclosed concrete truss structure according to claim 1, characterized in that: The lengths of the upper chord (31), the lower chord (32), the vertical bar (33), and the horizontal bar (36) are equal; the lengths of the first upper oblique web bar (341), the second upper oblique web bar (342), the first lower oblique web bar (343), and the second lower oblique web bar (344) are equal.

3. The fully enclosed concrete truss structure according to claim 2, characterized in that: The length relationship between the first upper inclined web member (341) and the upper chord member (31) is as follows: , where S is the length of the upper chord (31) and L is the length of the first upper diagonal web member (341).

4. The fully enclosed concrete truss structure according to claim 1, characterized in that: The first upper inclined web member (341) is inclined from the upper node to the inside of the steel pipe truss assembly (2), and the first lower inclined web member (343) is inclined from the lower node to the inside of the steel pipe truss assembly (2). The angles with the vertical member (33) are all 35° to 40°, the angles with the upper chord member (31) are all 45° to 50°, and the angles with the horizontal member (36) are all 45° to 50°.

5. A fully enclosed concrete truss structure according to claim 1, characterized in that: The second upper inclined web member (342) is inclined from the upper node to the inside of the steel pipe truss assembly (2), and the second lower inclined web member (344) is inclined from the lower node to the inside of the steel pipe truss assembly (2). The angles with the vertical member (33) are all 50° to 55°, the angles with the upper chord member (31) are all 35° to 40°, and the angles with the horizontal member (36) are all 35° to 40°.

6. A fully enclosed concrete truss structure according to claim 1, characterized in that: Both the upper and lower wrapping nets are made of glass fiber mesh with a pore size of 10-20 mm, diamond-shaped pores, and fiber diameters of 2-3 mm.

7. A fully enclosed concrete truss structure according to claim 1, characterized in that: Both the first reinforcing mesh and the second reinforcing mesh are high-strength glass fiber meshes with a pore size of 5-10 mm, square mesh openings, and fiber diameters of 4-4.5 mm.

8. A construction method for a fully enclosed concrete truss structure according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Prepare the upper chord (31), lower chord (32), vertical bar (33) and horizontal bar (36), wrap them with reinforcing mesh and weld them into a three-dimensional structure, and set nodes at the intersection points to obtain the steel pipe truss shell; S2. An inclined web member assembly (34) is installed inside the steel pipe truss shell. A wrapping net is installed on the outside of the inclined web member assembly (34) and a fixing rod assembly (35) is welded on. After the connecting net is installed on the outside of the steel pipe truss shell, a steel pipe truss unit (3) is formed. S3. Connect several steel pipe truss units (3) with bolts, and connect several steel plates (1) with the steel pipe truss units (3) at the edge with bolts to form a steel pipe truss structure; S4. Apply adhesive to the surfaces of the reinforcing mesh, wrapping mesh, and connecting mesh. Pour concrete into sections for the steel pipe truss structure. During the pouring process, continuously grout to remove gaps. After pouring, vibrate with a vibrating plate. After the concrete has initially solidified, remove the formwork and trim the surface to obtain a fully wrapped concrete truss structure.

9. The construction method of a fully enclosed concrete truss structure according to claim 8, characterized in that: In S4, the adhesive used is one of epoxy resin adhesive, polyurethane adhesive and acrylate adhesive.

Images