A demountable truss structure

Abstract

This utility model discloses a detachable truss structure, belonging to the field of large-scale steel structure engineering technology. The truss structure includes several prefabricated truss units, connecting components, and a positioning and guiding structure. Each truss unit consists of an upper chord, a lower chord, and web members, with the web members inclinedly connected between the upper and lower chords to form a triangular stable structure. The connecting components are connecting grooves pre-welded to the joints, connected by insertion fitting and rivets. The connecting holes and rivet rods use a precision clearance fit and a full-expansion process to achieve a gapless connection. The positioning and guiding structure uses positioning pins and guide grooves to ensure rapid and accurate on-site docking. This utility model effectively solves the transportation limitations of ultra-wide and ultra-long trusses through factory prefabrication and rapid on-site assembly, significantly reducing transportation and construction costs, improving installation efficiency, and ensuring the overall mechanical performance of the truss and the reliability of the connection nodes. It is suitable for large-span stadiums, bridges, and other engineering projects.

Description

Technical Field

[0001] This utility model relates to a detachable truss structure, belonging to the field of large steel structure engineering technology. Specifically, it relates to a detachable truss structure suitable for ultra-wide and ultra-long dimensions, especially suitable for cross-regional construction scenarios restricted by transportation conditions (such as road width restrictions, bridge load restrictions, and tunnel clearance restrictions). It can achieve rapid construction of large trusses through unit disassembly and transportation + on-site assembly. Background Technology

[0002] Trusses, as lattice-type load-bearing structures composed of straight bars, are widely used in large-scale projects due to their advantages of light weight, high strength, and large span. However, traditional trusses are mostly integral welded structures, which have significant technical drawbacks.

[0003] (a) Transportation difficulties are prominent.

[0004] 1. Low feasibility of transportation; Under existing highway transport standards, the width limit for ordinary freight vehicles is usually 2.5m and the height limit is 4.5m. Oversized / overheight trusses cannot be transported by conventional vehicles. If special transport vehicles are used, temporary traffic control must be applied for, and some road sections (such as rural roads and old tunnels) are still impassable.

[0005] 2. High transportation costs; The cost of special transportation for ultra-large components is 3 to 5 times that of conventional transportation, and the transportation route needs to be planned in advance and the transportation carrier needs to be reinforced, which further increases the project cost.

[0006] 3. High risks associated with on-site installation; If the entire super-large truss is forcibly transported to the site, it will require the use of super-large lifting equipment (such as a thousand-ton crawler crane) for hoisting. This not only results in high equipment rental costs but is also subject to limitations in on-site construction space, which could easily lead to hoisting safety accidents.

[0007] (ii) Significant defects in the welded connection.

[0008] 1. Damage to material properties; High welding temperatures (≥800℃) alter the metallographic structure of the material, leading to coarse grains and reduced toughness. At the same time, residual stress (which can reach 60% to 80% of the material's yield strength) is generated, significantly reducing the material's fatigue performance. Under long-term alternating loads, welded joints are prone to fatigue cracks, causing premature truss failure and seriously threatening structural safety.

[0009] 2. The quality of the joints is unstable; Welding is prone to defects such as cracks, porosity, and slag inclusions due to operation and environmental factors. The defect rate is about 10% to 15%, requiring additional investment in non-destructive testing equipment for inspection. Moreover, defects can further increase the risk of fatigue failure.

[0010] 3. Poor maintenance flexibility; Welding is a permanent connection. When a part is damaged, it needs to be cut and removed, which can easily damage the surrounding structure and generate new residual stress. In the end, the whole thing can only be scrapped, resulting in serious waste of resources. At the same time, welding operations require large equipment, and there are high safety risks when operating at heights and in confined spaces. In addition, it generates toxic fumes that pollute the environment.

[0011] In existing technologies, the solutions for truss disassembly mostly adopt "welding disassembly + on-site welding splicing", but this method has the following drawbacks: the on-site welding process is complex, requiring preheating before welding and flaw detection after welding, and the construction cycle is long; the welded joints are prone to stress concentration, affecting the overall mechanical properties of the truss; and the welding quality is greatly affected by the on-site environment (such as temperature, humidity and wind speed), making it difficult to guarantee stability.

[0012] Therefore, there is an urgent need for a truss structure design that can achieve efficient disassembly and transportation, rapid on-site assembly, and ensure structural strength, in order to solve the problems of difficult transportation, low installation efficiency, and high cost of existing large trusses. Utility Model Content

[0013] This invention overcomes the shortcomings of existing technologies and provides a detachable truss structure. By optimizing the truss disassembly method and connection structure, it achieves "factory prefabricated unit disassembly and transportation + on-site rapid assembly with bolts / rivets". While meeting transportation constraints, it ensures the overall mechanical performance of the truss, reduces transportation and construction costs, and shortens the construction cycle.

[0014] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: a detachable truss structure, including a number of prefabricated truss units, connecting components and positioning guide structures, wherein each prefabricated truss unit is detachably connected by the connecting components to form a spatial truss structure unit; the spatial truss structure units are sequentially connected by the positioning guide structures to form a complete truss structure. The truss unit consists of an upper chord, a lower chord, and web members. The upper chord is parallel to the lower chord and coplanar with the web members. The web members are inclinedly connected between the upper chord and the lower chord to form a triangular stable structure. The connecting assembly consists of a connecting groove pre-welded to the connection part of the upper chord and lower chord, and the end of the web member. The connecting groove at the end of the web member can be matched and inserted into the connecting groove of the connection part of the upper chord and lower chord. At least two connecting holes are correspondingly opened in the connecting groove, and the connecting holes are symmetrically distributed along the central axis of the web member. Rivets are inserted into the connecting holes between the web member and the upper and lower chords, and the rivets connect the upper and lower chords to the web member. Reinforcing ribs are provided in the connecting groove to increase the structural strength of the connection.

[0015] Furthermore, the clearance between the connecting hole and the rivet rod is controlled at 0.1 to 0.3 mm, laying the foundation for the subsequent expansion process.

[0016] Furthermore, the connection between the upper and lower chords and the connecting groove at the end of the web members are subjected to vibration aging after welding to relieve stress, so that the residual stress is ≤50MPa, thereby reducing the impact of internal stress on fatigue performance.

[0017] Furthermore, the positioning and guiding structure is provided with positioning pins and positioning holes at the docking ends of adjacent spatial truss structural units. The gap between the diameter of the positioning pin and the diameter of the positioning hole is ≤0.1mm. During on-site assembly, the positioning pins are used to quickly align the components and avoid docking deviations. In addition, guide grooves are provided on the docking flange plates of the upper chord and the lower chord to achieve "guidance first, then fastening" in conjunction with the positioning pins, thereby improving assembly efficiency.

[0018] Furthermore, the rivets are made of stainless steel or high-strength aluminum alloy, and their tensile and shear strengths are not lower than those of the truss unit material, avoiding local stress concentration caused by insufficient strength of the connectors; the rivet shank length is equal to the sum of the thicknesses of the two ends plus 1.4 times the rivet shank diameter, and the rivet head diameter is 2 to 2.5 times the shank diameter, increasing the bearing area and evenly distributing the load; the rivets are crimped using hydraulic riveting equipment, applying axial pressure and radial expansion force to the rivet shank after piercing, causing the shank to plastically deform and expand to fill the 0.1 to 0.3 mm gap until it is completely in contact with the inner wall of the hole; continued pressure is applied to press the shank end into a second rivet head with the same size as the fixed rivet head, forming a double rivet head + clearance-free fit structure, completely eliminating the risk of loosening, ensuring uniform load transfer, and protecting fatigue performance.

[0019] Furthermore, a 2-3mm thick rubber or polyurethane gasket is provided between the adjacent planes of the connecting groove of the upper chord and lower chord and the connecting groove of the end of the web member after they are inserted. The gap between the through hole of the gasket and the rivet rod is ≤0.1mm. After riveting, the gasket is pressed tightly, which not only fills the tiny gaps to prevent corrosion, but also buffers vibration and impact.

[0020] In this invention, the connection between the web member and the upper and lower chords can be replaced by a sleeve-and-screw structure instead of a rivet connection structure. The sleeve-and-screw structure includes a blind tube integrally or welded to the connection part between the upper and lower chords and the web member. The end wall of the blind tube, i.e., the tube end plate, is provided with a through hole. The blind tubes at the connection parts of the upper and lower chords and the web member are connected by a screw. A sleeve is fitted on the outside of the screw. The sleeve is located on the screw between the blind tubes at the connection parts of the upper and lower chords and the web member. A set screw is provided on the sleeve. The set screw passes through the sleeve and presses against the screw.

[0021] Furthermore, the sleeve is a hexagonal sleeve, and the screw is a hexagonal screw.

[0022] Furthermore, one end of the screw is a nut, which fits inside the blind tube of the web member connection. The other end of the screw extends into the blind tube of the upper chord and lower chord connection, and a female sleeve is integrally provided on the end wall of the blind tube. The end of the screw is inserted into the female sleeve in a matching manner.

[0023] Compared with existing technologies, this utility model has the following advantages: By disassembling the super-large truss into prefabricated units that meet conventional transportation conditions, this utility model eliminates the need for special transport vehicles, reducing transportation costs by 40% to 60%, and is adaptable to the transportation routes of most construction sites; no complex welding processes are required on-site, and the assembly time of a single truss is shortened to 2-3 hours (compared to 8-10 hours for traditional welding assembly) through rapid bolt or rivet connections, significantly shortening the construction cycle and improving installation efficiency; through high-strength bolts or hot rivets, the shear strength of the nodes can reach more than 90% of the strength of the parent material, and the positioning and guiding structure ensures docking accuracy, ensuring that the overall mechanical properties of the truss are basically consistent with the overall prefabricated truss, guaranteeing structural strength; the number of units and the connection method can be flexibly adjusted according to the truss size and stress requirements, making it suitable for truss structure design in different scenarios such as large-span stadiums, bridges, and factories, with strong adaptability; this utility model produces no welding fumes or waste emissions throughout the entire process, with a unit reuse rate of ≥90%, reducing material waste, meeting environmental protection requirements, and being environmentally friendly and resource-efficient. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings.

[0025] Figure 1 This is a structural diagram of the present invention when it is a two-tube truss (three-tube and four-tube trusses are not shown).

[0026] Figure 2 for Figure 1 A magnified view of a portion of region A in the middle.

[0027] Figure 3 This is a schematic diagram of the web member connection of this utility model.

[0028] Figure 4 This is a magnified view of region B in diagram 3.

[0029] Figure 5 This is a schematic diagram of the structure before the rivets are riveted in this utility model.

[0030] Figure 6 This is a schematic diagram of the structure after the rivets are riveted in this utility model.

[0031] Figure 7 This is a schematic diagram showing the state of cutting off one end of the rivet using a cutting tool in this utility model.

[0032] Figure 8 The impact tool top of this utility model Figure 7 A schematic diagram showing the state of one end of the rivet being cut off.

[0033] Figure 9 This is a schematic diagram (rear view) of the overall loading and transportation of this utility model using a space truss structure unit.

[0034] Figure 10 This is a side view of the schematic diagram of the overall loading and transportation of this utility model using a space truss structure unit.

[0035] Figure 11 This is a rear view of the truss unit of this utility model being loaded and transported in a ladder-shaped component unit.

[0036] Figure 12 This is a side view of the truss unit of this utility model being loaded and transported in a ladder-shaped component unit.

[0037] Figure 13 This is a schematic diagram (rear view) of the truss unit of this utility model being transported in a single tube configuration.

[0038] Figure 14 This is a side view of the truss unit of this utility model being transported in a single-tube configuration.

[0039] Figure 15 This is a schematic diagram of the structure of this utility model, which connects the chord and the web member through a screw and set screw.

[0040] Figure 16 for Figure 15 A magnified view of a portion of region C.

[0041] Figure 17 This is an exploded view of the structure of this utility model, which connects the chord and the web member by a screw and set screw.

[0042] Figure 18 for Figure 17 A magnified view of a portion of region D.

[0043] Figure 19 This is an exploded view of the set screw connection of the web screw.

[0044] In the diagram: 1 is a truss unit, 11 is an upper chord, 12 is a lower chord, 13 is a web member, 14 is a connecting groove, 15 is a rivet, 16 is a sleeve, 17 is a screw, 18 is a set screw, 19 is a blocking plate, and 2 is a space truss structure unit. Detailed Implementation

[0045] The present invention will be further described below with reference to specific embodiments.

[0046] like Figures 1 to 19As shown, this utility model includes several prefabricated truss units, connecting components, and a positioning and guiding structure. Each prefabricated truss unit is detachably connected via the connecting components to form a complete truss structure; wherein: The truss unit, serving as the main structural element, consists of an upper chord, a lower chord, and web members. The upper and lower chords are parallel, while the web members are connected at an angle to form a triangular, stable structure (the triangular structure inherently resists lateral displacement, enhancing overall stability). The ends of the upper chord, lower chord, and web members extend to the same plane, forming flat connection ends. Connection holes are provided at each end according to load-bearing requirements, with at least two holes at each end, symmetrically distributed along the central axis (ensuring uniform stress distribution and avoiding stress concentration). The clearance between the connection holes and the rivet rods is strictly controlled within 0.1–0.3 mm, laying the foundation for subsequent expansion processes. After welding inside the unit, a vibration aging process is used to relieve stress, ensuring residual stress ≤50 MPa, further reducing the impact of internal stress on fatigue performance.

[0047] Positioning and guiding structure: Positioning pins and positioning holes are set at the docking ends of adjacent prefabricated units (the gap between the diameter of the positioning pin and the diameter of the positioning hole is ≤0.1mm). During on-site assembly, the positioning pins are used to quickly align the units and avoid docking deviations. Guide grooves are set on the docking flange plates of the upper chord and the lower chord, which, together with the positioning pins, achieve "guidance first, then fastening" to improve assembly efficiency.

[0048] Rivet connectors and expansion process: Rivets are made of stainless steel (such as 316 stainless steel, tensile strength ≥580MPa) or high-strength aluminum alloy (such as 7075~T6, tensile strength ≥570MPa) to ensure that the tensile and shear strength is not lower than that of the truss unit material, and to avoid local stress concentration caused by insufficient strength of the connectors.

[0049] The rivet structure is as follows: rivet shank length = sum of the thicknesses of the two ends + 1.4 times the rivet shank diameter (to ensure a complete second rivet head is formed after riveting); the rivet head diameter is 2 to 2.5 times the shank diameter (to increase the bearing area and evenly distribute the load).

[0050] Swelling process: Using hydraulic riveting equipment (pressure 15-25MPa), axial pressure and radial expansion force are applied to the rivet rod after piercing, causing the rod to plastically deform and swell to fill the gap of 0.1-0.3mm until it is completely in contact with the inner wall of the hole; pressure is continued to press the end of the rod into a second rivet head with the same size as the fixed rivet head, forming a "double rivet head + zero clearance fit" structure, which completely eliminates the risk of loosening, ensures uniform load transfer, and protects fatigue performance.

[0051] Sealing and corrosion protection optimization: A 2-3mm thick rubber or polyurethane gasket (compression 30%-50%) is placed between adjacent ends, with a gap of ≤0.1mm between the gasket's through hole and the rivet shank; after riveting, the gasket is compressed, both filling tiny gaps to prevent corrosion and buffering vibration and impact (reducing fatigue damage to the material from alternating loads). The unit surface is coated with a 50-100μm thick epoxy resin (with added UV-resistant components for outdoor applications) or polyvinyl chloride coating, fully covering the outer surface (including non-connection areas at the connection ends), improving moisture resistance and corrosion resistance, and avoiding the cumulative damage from corrosion and fatigue.

[0052] In this invention, the connection between the web member and the upper and lower chords can be achieved using a sleeve-and-screw structure instead of a rivet connection. The sleeve-and-screw structure includes a blind tube integrally formed or welded to the connection point between the upper and lower chords and the web member. The end wall of the blind tube, i.e., the tube's end plate, has a through hole. The blind tubes at the upper and lower chord connection points and the web member connection point are connected by a screw. A sleeve is fitted onto the outside of the screw, positioned on the screw between the blind tubes at the upper and lower chord connection points and the web member connection point. A set screw is provided on the sleeve, passing through the sleeve and pressing against the screw. The sleeve is a hexagonal sleeve, and the screw is also hexagonal. One end of the screw is a nut, which fits inside the blind tube of the web member connection. The other end of the screw extends into the blind tube of the upper chord and lower chord connection, and a female sleeve is integrally provided on the end wall of the blind tube. The end of the screw is inserted into the female sleeve.

[0053] The installation process of the hexagonal screw and the web member in this utility model is as follows: 1. Pass the hexagonal screw through the plug plate of the web rod; 2. Fit the hexagonal sleeve onto the hexagonal screw; 3. Tighten the set screw; 4. Weld the web member plug plate to the web member.

[0054] This invention utilizes a hexagonal anti-rotation mating structure of a hexagonal screw and a hexagonal sleeve. During installation, no additional tools are needed to fix the screw; simply screwing the hexagonal sleeve into the main rod connection hole completes the connection between the web member and the main rod. Simultaneously, the pre-set connection hole on the main rod ensures precise positioning of the web member, significantly reducing preparation and installation time, improving assembly efficiency, and resulting in high installation efficiency. The tightening effect of the set screw effectively prevents the hexagonal sleeve from loosening, ensuring the connection stability between the main rod and the web member, reducing safety hazards, and demonstrating strong structural stability. This invention employs a combination of threaded connection and set screw fixing. Disassembly only requires unscrewing the set screw and hexagonal sleeve to separate the main rod and web member without damage to the components. It can be reused multiple times, reducing operating costs, and is convenient for transportation and storage, as well as disassembly and reuse. This invention allows for adjustment of the material (such as steel, aluminum alloy, etc.) and size of the main rod and web member according to different load-bearing requirements, making it suitable for various scenarios such as building construction, stage construction, and warehouse shelving, with broad application prospects and wide adaptability.

[0055] This utility model consists of multiple independent truss units that are detachably connected by rivets or screws to form a complete truss. Each unit can be transported independently, and adjacent units are fixed together by end connection holes and rivets, replacing the traditional integral welded structure. This fundamentally improves the structural form, solving both transportation problems and avoiding welding defects.

[0056] This invention controls the clearance between the rivet shank and the connecting hole to be between 0.1 and 0.3 mm. During riveting, axial pressure and radial expansion force are applied using specialized equipment, causing the rivet shank to plastically deform and fill the clearance, forming an interference fit. After full expansion, the rivet shank and the inner wall of the hole are completely fitted without any gaps. Through precise clearance control and plastic deformation technology, a gapless connection is achieved, significantly improving the connection stiffness and shear resistance, filling the gap in gapless riveting connections.

[0057] In this utility model, the upper chord, lower chord, and web members of the truss unit extend to the same plane to form a connection end. Each end has at least two connection holes symmetrical about the central axis, and an elastic, wear-resistant sealing gasket with a through hole is provided between adjacent ends. By ensuring a good fit through coplanarity, uniform force distribution through symmetrical holes, and sealing and buffering with gaskets, the reliability of the connection is improved in a coordinated manner.

[0058] This utility model uses a high-strength alloy with tensile and shear strength no less than that of the truss unit material. The rivet shank length is greater than the sum of the thicknesses of the two ends. One end is a fixed rivet head, and the other end is drilled and riveted to form a second rivet head, achieving double fixation. By limiting parameters, the connection strength and stability are ensured, filling the technical gap in the details of truss riveting connections.

[0059] This invention involves coating the truss unit surface with a 50-100 μm thick epoxy resin or polyvinyl chloride anti-corrosion coating, covering the entire outer surface (including non-connection areas at the connection ends). Parameterized limitations ensure stable anti-corrosion performance and extend service life in harsh environments.

[0060] This utility model's rivet connection involves no high-temperature heat input, generates no welding residual stress, and features a gapless fit that ensures uniform load distribution and no stress concentration, guaranteeing that the material's fatigue performance is consistent with the original properties of the base material (fatigue strength retention rate ≥98%). Compared to traditional welding, where residual stress and defects reduce material fatigue performance by 30%–50%, this solution is suitable for long-term alternating load scenarios. It fundamentally avoids this risk through its connection method, filling the technological gap in "truss fatigue performance protection."

[0061] This utility model's prefabricated unit completes the integrated processing of "rod welding and forming → anti-corrosion treatment (galvanizing / anti-corrosion coating) → pre-assembly of connecting components (flange plates, rivet plates, positioning pins)" in the factory. On-site, only docking and fastening are required, without additional processing. Through factory-integrated processing, the structural accuracy of the prefabricated unit is guaranteed (error ≤ 0.5mm / m), while reducing on-site work and minimizing the environmental impact on construction quality.

[0062] When reusing this invention, one end of the rivet is cut off with a shearing tool, and the other end is pushed out with an impact tool to remove the rivet, thus avoiding damage to the truss structure and achieving high utilization. During transportation, the assembled space truss structure unit can be transported as a whole on a vehicle, which can be loaded onto a regular flatbed truck; alternatively, the truss unit can be transported as a component or pre-assembled modular unit.

[0063] Example 1: A double-slope enclosed coal shed (slope angle 35°) in a snowy mining area 1. Coal shed and truss parameters; The coal shed is 150m long, 48m wide, and has a double-sloped roof height of 10m (slope angle 35°). Each single double-sloped truss has a span of 48m, a lower chord length of 48m, and an upper chord (slope direction) length of 29m / member (two members form the double-sloped upper chord). Each truss weighs 62 tons. The mining area roads have a width limit of 2.2m and a weight limit of 25 tons, making it impossible to transport traditional composite trusses (3.2m wide).

[0064] 2. Single-pipe splitting scheme; Top chord slope single pipe: The two 29m slope chord members are divided into three single pipes (9m, 9m, and 11m in length) for each member. The single pipe has a specification of Φ273mm×12mm and a weight of 1.2 tons per member. Each single pipe has flanges (12mm thick) at both ends. Lower chord horizontal single tube: The 48m lower chord is divided into 4 sections of 12m single tubes (Φ325mm×14mm, single weight 1.7 tons / piece). Single-tube web members: The diagonal web members (matching a 35° slope angle) are split into 6m single tubes (Φ159mm×8mm, single weight 0.29 tons / piece), and the vertical web members are split into 4m single tubes (Φ180mm×10mm, single weight 0.45 tons / piece). Unit division: On-site, the single tubes will be assembled into 2 slope units (each unit spans 24m, including 3 upper chord single tubes / slope, 2 lower chord single tubes, and 12 web single tubes), with a unit weight of 28 tons (optimized to 22 tons by "splitting the web single tubes and transporting them in 2 trips" to meet weight restrictions).

[0065] 3. Single-pipe assembly and slope angle control; Single tube transportation: Single tubes are transported using 10-ton trucks, with each truck carrying 35 web bar single tubes + 15 chord bar single tubes. Only 3 trips are needed from the factory to the site (traditional combined poles require 8 special transportation trips). Slope top node assembly: Use a 5-ton truck crane to lift the single pipe, and connect the two slope chord single pipes (Φ273mm) and the vertical web single pipes (Φ180mm) with triangular connectors (14mm thick). The connectors are equipped with 6 M18 bolts (8.8 grade anti-corrosion). Use an angle gauge to calibrate the slope angle (35°±0.5°) to ensure drainage slope. Unit splicing: Two sloped units are connected by a lower chord flange connecting plate (18mm thick, with 8 M24 bolts), and the upper chord sloped single pipe is connected by a flange plate (with 6 M20 bolts). The web members are connected by Φ20mm hot riveting rivets (temperature 860~880℃, pressure 32MPa). Quality inspection: torque test of single pipe connection bolts (final tightening torque of M24 bolts is 380 N·m), ultrasonic flaw detection pass rate of rivets is 100%, slope angle deviation of double slope trusses is ≤0.3° (meets drainage requirements), and full load deflection is 18 mm (design allowance is ≤22 mm).

[0066] 4. Implementation results; The single-pipe transportation cost is reduced by 70%, on-site assembly requires no welding, the slope angle accuracy is high, and snow can slide off naturally within 24 hours in winter without water accumulation or rust problems.

[0067] Example 2: A double-slope truss canopy (slope angle 32°) for a large high-speed railway station building 1. Project Overview; The high-speed railway station building is massive in scale, with a double-slope truss canopy covering an area of ​​30,000 square meters, providing shelter from wind and rain for passengers and trains. Each double-slope truss spans 50 meters, with a lower chord length of 50 meters and upper chord (slope direction) length of 30 meters per member (two members form the double-slope upper chord), each member weighing 70 tons. Although the surrounding roads are wide, the construction process must not disrupt traffic, placing extremely high demands on transportation and construction organization.

[0068] 2. Single-tube disassembly and transportation; Top chord slope single pipe: Each 30m slope chord is divided into 3 single pipes with lengths of 9m, 10m and 11m respectively. Q460 high-strength steel pipes with specifications of Φ300mm×14mm are selected, with a single weight of 1.4 tons / piece, and 14mm thick flanges with bolt holes are provided at both ends.

[0069] Lower chord horizontal single tube: The 50m lower chord bar is divided into 5 sections of 10m single tubes, with specifications of Φ355mm×16mm and a single weight of 1.9 tons / piece.

[0070] Single-tube web members: The diagonal web members (suitable for 32° slope angle) are split into 5m single tubes with specifications of Φ180mm×10mm and a single weight of 0.32 tons / piece; the vertical web members are split into 4m single tubes with specifications of Φ203mm×12mm and a single weight of 0.5 tons / piece.

[0071] Transportation Arrangement: Customized low-flatbed semi-trailers will be used to transport single tubes. Each truck can carry 40 web member single tubes and 20 chord member single tubes. The materials will be transported in batches according to the construction progress to ensure an orderly supply of materials at the construction site and to avoid traffic congestion.

[0072] 3. On-site assembly process; Ground assembly unit: Utilizing the open space of the station area, the single tubes are first assembled into slope units on the ground. Each unit has a span of 25m and includes 3 upper chord single tubes per slope, 2 lower chord single tubes, and 10 web single tubes. During the assembly process, a total station is used for precise measurement and positioning to ensure that the positional deviation of each single tube is controlled within ±3mm.

[0073] Unit hoisting and splicing: Two 200-ton crawler cranes are used for unit hoisting, connecting the two sloping units in mid-air. The chord members are connected using 18mm thick flange plates with eight M24 10.9 grade high-strength bolts; the web members are connected using 22mm diameter ML30MnB hot-riveting rivets, with the hot-riveting temperature controlled between 850 and 870℃ and the pressure maintained at 35MPa to ensure a firm and reliable connection.

[0074] Slope Angle and Overall Verification: The assembled double-slope truss was measured and verified using a high-precision electronic level and total station. The slope angle deviation of the double-slope truss was ultimately controlled within ±0.3°, meeting the drainage and structural design requirements. The overall structure underwent load testing, and all performance indicators met the design standards.

[0075] 4. Implementation results; The single-tube split transportation effectively solved the traffic pressure problem during construction. The ground assembly unit and then hoisting and splicing method greatly improved the construction efficiency. The entire canopy construction cycle was shortened by 20% compared with the traditional integral truss construction, and the construction quality was reliably guaranteed.

[0076] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A detachable truss structure, characterized in that, It includes several prefabricated truss units, connecting components, and positioning and guiding structures. Each prefabricated truss unit is detachably connected by the connecting components to form a spatial truss structure unit. The spatial truss structure units are sequentially connected by the positioning and guiding structures to form a complete truss structure. The truss unit consists of an upper chord, a lower chord, and web members. The upper chord is parallel to the lower chord and coplanar with the web members. The web members are inclinedly connected between the upper chord and the lower chord to form a triangular stable structure. The connecting component is a connecting groove pre-welded to the connection part of the upper chord and lower chord, and the end of the web member. The connecting groove at the end of the web member can be matched and inserted into the connecting groove of the connection part of the upper chord and lower chord. At least two connecting holes are opened in the connecting groove, and the connecting holes are symmetrically distributed along the central axis of the web member. Rivets are inserted into the connecting holes between the web member and the upper and lower chords, and the rivets connect the upper and lower chords to the web member.

2. The detachable truss structure according to claim 1, characterized in that, The clearance between the connecting hole and the rivet rod is controlled at 0.1 to 0.3 mm, which lays the foundation for the subsequent expansion process.

3. A detachable truss structure according to claim 1, characterized in that, After welding, the connection between the upper and lower chords and the connecting groove at the end of the web members are subjected to vibration aging process to relieve stress, so that the residual stress is ≤50MPa, thereby reducing the impact of internal stress on fatigue performance.

4. A detachable truss structure according to claim 1, characterized in that, The positioning and guiding structure consists of positioning pins and positioning holes at the docking ends of adjacent spatial truss structural units. The gap between the diameter of the positioning pin and the diameter of the positioning hole is ≤0.1mm. During on-site assembly, the positioning pins allow for quick alignment, avoiding docking deviations. Furthermore, guide grooves are provided on the docking flange plates of the upper and lower chords, which, together with the positioning pins, achieve "guidance first, then fastening," improving assembly efficiency.

5. A detachable truss structure according to claim 2, characterized in that, The rivets are made of stainless steel or high-strength aluminum alloy, with tensile and shear strengths no lower than those of the truss unit material, avoiding localized stress concentration caused by insufficient strength of the connectors. The rivet shank length is equal to the sum of the thicknesses of the two ends plus 1.4 times the rivet shank diameter, and the rivet head diameter is 2 to 2.5 times the shank diameter, increasing the bearing area and evenly distributing the load. The rivets are crimped using hydraulic riveting equipment, applying axial pressure and radial expansion force to the rivet shank after piercing, causing the shank to plastically deform and expand to fill the 0.1 to 0.3 mm gap until it is completely fitted with the inner wall of the hole. Continued pressure is applied to press the shank end into a second rivet head that matches the size of the fixed rivet head, forming a double rivet head + clearance-free fit structure, completely eliminating the risk of loosening, ensuring even load transfer, and not damaging the fatigue performance of the material.

6. A detachable truss structure according to claim 1, characterized in that, A 2-3mm thick rubber or polyurethane gasket is provided between the adjacent planes of the connecting grooves of the upper chord and lower chord and the connecting grooves of the web end after they are inserted. The gap between the through hole of the gasket and the rivet rod is ≤0.1mm. After riveting, the gasket is pressed tightly, which not only fills the tiny gaps to prevent corrosion, but also buffers vibration and impact.

7. A detachable truss structure according to claim 1, characterized in that, The connection between the web member and the upper and lower chords can be replaced by a sleeve-set screw structure instead of a rivet connection structure. The sleeve-set screw structure includes a blind tube integrally or welded to the connection part between the upper and lower chords and the web member. The blind tube has a through hole on its end wall. The blind tubes at the connection parts of the upper and lower chords and the web member are connected by a screw. A sleeve is fitted on the outside of the screw. The sleeve is located on the screw between the blind tubes at the connection parts of the upper and lower chords and the blind tubes at the connection part of the web member. A set screw is provided on the sleeve. The set screw passes through the sleeve and presses against the screw.

8. A detachable truss structure according to claim 7, characterized in that, The sleeve is a hexagonal sleeve, and the screw is a hexagonal screw.

9. A detachable truss structure according to claim 7, characterized in that, One end of the screw is a nut, which fits inside the blind tube of the web member connection. The other end of the screw extends into the blind tube of the upper chord and lower chord connection, and a female sleeve is integrally provided on the end wall of the blind tube. The end of the screw is inserted into the female sleeve.

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