A fast-assembly reinforcing system for the gable of an ultrahigh steel structure factory building and a construction method

Abstract

This invention relates to a quick-installation reinforcement system and construction method for the gable walls of ultra-high steel structure factory buildings. The quick-installation reinforcement system includes wind-resistant columns and wind-resistant trusses spanning the wind-resistant columns. The wind-resistant trusses are formed by connecting upper chords, lower chords, and web members. The quick-installation reinforcement system includes: a truss support reinforcement assembly, comprising multiple sets of variable stiffness diagonal support units, each set being bolted and fixed to the corresponding upper and lower chords; and a truss reinforcement assembly, comprising: a lower chord composite reinforcement structure, covering the outer surface of the lower chord and extending to the outside of the connection node between the lower chord and the web members; and an external prestressed reinforcement structure for the lower chord, segmented along the length of the lower chord, with each segment anchoring multiple prestressed tendons circumferentially along the lower chord. This invention, through the combination of external support and double reinforcement, significantly improves the stiffness and load-bearing capacity of the wind-resistant truss, offering efficient construction and structural safety and reliability, and is suitable for the rapid reinforcement and renovation of gable walls of ultra-high steel structure factory buildings.

Description

Technical Field

[0001] This invention relates to the field of building structure technology, and in particular to the reinforcement of building structure engineering, specifically to a quick-installation reinforcement system and construction method for the gable wall of an ultra-high steel structure factory building. Background Technology

[0002] As industrial buildings develop towards larger and taller structures, ultra-high steel structure factory buildings with eaves heights exceeding 40m are widely used in heavy industry, warehousing and logistics, and other fields. The existing wind-resistant rigid frame on the gable wall is the core structure for resisting the coupled effects of horizontal wind loads and vertical loads. This existing structure includes wind-resistant columns and wind-resistant trusses spanning the wind-resistant columns. The wind-resistant trusses are formed by welding / bolting together the upper chord, lower chord, and web members, and are key components for the structural safety of the factory building.

[0003] However, under severe conditions such as extreme strong winds and short-term strong gusts, the existing gable wall wind-resistant rigid frame has been subjected to alternating loads for a long time, gradually exposing many structural defects: the overall lateral stiffness of the wind-resistant truss is insufficient, and it is prone to overall deformation; as the main load-bearing component, the bending stiffness of the lower chord is difficult to meet the load coupling requirements, and it is prone to bending deformation and stress concentration caused by the force being transferred to the node area; the welded intersection node of the web members and the lower chord members is subjected to alternating stress for a long time, and is prone to fatigue failure; traditional reinforcement methods mostly adopt on-site welding and truss unloading construction, which not only has a long construction period and high safety risks, but also affects the normal production and operation of the plant.

[0004] To address the aforementioned issues, the development of a prefabricated, quick-installation reinforcement system adapted to existing gable wall wind-resistant frames is urgently needed in this field. Through modular and bolted reinforcement structure design, it aims to achieve the dual goals of rapid construction and improved structural performance. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the main purpose of this invention is to provide a quick-installation reinforcement system and construction method for the gable wall of ultra-high steel structure factory buildings, so as to realize the prefabricated quick-installation reinforcement of existing wind-resistant rigid frames and solve problems such as insufficient lateral stiffness of existing structures, poor bending capacity of lower chord members, and easy fatigue failure of joints.

[0006] The technical solution of the present invention is as follows:

[0007] This invention proposes a quick-installation reinforcement system for the gable walls of ultra-high steel structure factory buildings, adaptable to existing wind-resistant gable wall frames. The wind-resistant gable wall frame includes wind-resistant columns and wind-resistant trusses spanning the wind-resistant columns. The wind-resistant trusses are formed by connecting upper chords, lower chords, and web members. The quick-installation reinforcement system includes:

[0008] A truss support and reinforcement assembly, located on the outer side of the wind-resistant truss away from the gable wall, includes:

[0009] Multiple sets of variable stiffness diagonal support units, each set of which is bolted and fixed to the corresponding upper and lower chord members, are used to enhance the overall support stiffness and lateral displacement resistance of the wind-resistant truss; and

[0010] Truss reinforcement and strengthening components, including:

[0011] A composite reinforcement structure for the lower chord is wrapped around the outer surface of the lower chord and extends to the outside of the connection node between the lower chord and the web member, in order to improve the bending stiffness of the lower chord.

[0012] The external prestressed reinforcement structure for the lower chord is arranged in segments along the length of the lower chord, and each segment has multiple prestressed tendons anchored circumferentially along the lower chord to apply active prestress to the lower chord.

[0013] Preferably, the wind-resistant truss is composed of two upper chords, two lower chords, and several web members connected together. The two upper chords and the two lower chords are arranged at intervals relative to each other. The web members are arranged in a triangle between the upper chords and the lower chords and are connected to the upper chords and the lower chords respectively to form a box truss structure.

[0014] Preferably, each set of variable stiffness inclined support units is a triangular structure, including two variable stiffness circular tubes. One of the two variable stiffness circular tubes is arranged obliquely, and one end of it is bolted to the upper chord. The other tube is arranged horizontally, and one end of it is bolted to the lower chord. The other ends of the two variable stiffness circular tubes are connected to each other. The end section of each variable stiffness circular tube is larger than its middle section section.

[0015] Preferably, the lower chord composite reinforcement structure is formed by alternating laying and curing of multiple layers of carbon fiber reinforced resin matrix composite material in two laying methods, one of which is a 0° axial continuous wrapping laying along the length direction of the lower chord, and the other is a 90° circumferential spaced clamp laying along the length direction of the lower chord.

[0016] Preferably, the carbon fiber reinforced resin matrix composite layer is made of carbon fiber cloth and bisphenol A type epoxy resin.

[0017] Preferably, the composite reinforcement structure of the lower chord extends to cover the outer side of the connection node between the lower chord and the web member by 150-200mm.

[0018] Preferably, the external prestressed reinforcement structure for the lower chord includes:

[0019] An anchoring end seat, which is detachably fixed to the lower chord at predetermined intervals;

[0020] Four prestressing tendons are arranged symmetrically along the circumference of the lower chord. The two ends of each prestressing tendon are anchored to the anchorage, and active prestress is applied to the lower chord by tensioning.

[0021] Preferably, the anchoring end seat adopts a split clamping structure, which consists of two mating clamping units. The two clamping units are locked and fixed to the outside of the lower chord by locking members to achieve anchoring of the external prestressing tendons.

[0022] Preferably, it further includes a web member node reinforcement structure, the web member node reinforcement structure comprising:

[0023] Microrods are symmetrically arranged on both sides of the connection node between the web member and the lower chord member. The two ends of the microrods are respectively bolted and fixed to the web member and the lower chord member by high-strength bolts.

[0024] Preferably, it also includes inter-column support structures, which are arranged in an X-shape between longitudinally adjacent wind-resistant columns, and multiple sets are evenly arranged along the height direction of the wind-resistant columns. Both ends of each set of inter-column support structures are bolted and fixed to the corresponding wind-resistant column.

[0025] The present invention also proposes a construction method for the above-described quick-installation reinforcement system, comprising the following steps:

[0026] Prefabrication preparation: Prefabricate in the factory the variable stiffness diagonal support unit of the truss support and reinforcement component, the lower chord composite reinforcement structure of the truss reinforcement and strengthening component, and the external prestressed reinforcement structure of the lower chord.

[0027] Truss support reinforcement: Variable stiffness diagonal support units are arranged on the outer side of the wind-resistant truss away from the gable wall, and the two ends of each variable stiffness diagonal support unit are respectively bolted and fixed to the upper chord and lower chord of the wind-resistant truss.

[0028] Truss reinforcement: Multiple layers of carbon fiber reinforced resin matrix composite material are alternately laid on the outer surface of the lower chord in two laying methods, so that they cover the outer surface of the lower chord and extend to the outside of the connection node between the lower chord and the web members; at the same time, external prestressing tendons are laid in sections along the length of the lower chord, and the two ends of the prestressing tendons are anchored to the anchoring device of the wind-resistant column. The tendons are tensioned and locked in stages according to the design prestress value to achieve active prestressing reinforcement of the lower chord.

[0029] The beneficial effects of this invention compared to existing technologies are as follows: The quick-installation reinforcement system of this invention is a prefabricated reinforcement structure adapted to the existing wind-resistant rigid frame design of ultra-high steel structure factory buildings. All components are prefabricated in the factory and bolted together on site, eliminating the need for hot welding and unloading of existing trusses. Through the coordinated design and precise layout of truss support reinforcement components, truss reinforcement components, web member node reinforcement structures, and inter-column support structures, it achieves a comprehensive performance improvement of the existing wind-resistant rigid frame of the gable wall. It solves core problems such as insufficient lateral stiffness, poor bending capacity of the lower chord, easy fatigue failure of nodes, and easy large deformation under extreme working conditions. It also significantly improves construction efficiency and reduces the impact of construction on factory production. At the same time, it takes into account structural adaptability, durability, and ease of later maintenance. The overall reinforcement effect is significant, and it is suitable for the quick-installation reinforcement and performance improvement of the wind-resistant rigid frame of the gable wall of ultra-high steel structure factory buildings. Specifically, it has at least the following effects:

[0030] (1) Significantly improved structural performance: The overall lateral stiffness of the wind-resistant truss is enhanced by the truss support reinforcement components. The composite reinforcement structure of the lower chord and the external prestressed reinforcement structure work together to improve the bending stiffness of the lower chord and control large deformation. The reinforcement structure of the web members reduces the stress amplitude of the nodes. The inter-column support structure enhances the overall stability of the wind-resistant columns. The synergistic effect of each structure increases the bearing capacity of the existing gable wind-resistant frame under extreme loads by 40%-60%, effectively solving the problems of existing structural deformation and node fatigue.

[0031] (2) High construction efficiency and no impact on production: All reinforcement structures are prefabricated in the factory and only need to be bolted and assembled on site. The construction cycle is shortened by more than 50% compared with traditional reinforcement methods. Moreover, there is no need to unload the existing wind-resistant frame or carry out hot work during the construction process, so it does not affect the normal production and operation of the factory.

[0032] (3) It has strong adaptability. The parameters of each structure can be flexibly adjusted according to the actual working conditions of the factory, and it can be adapted to ultra-high steel structure factory buildings of different specifications.

[0033] (4) Good durability and convenient maintenance: The reinforcement structure uses carbon fiber reinforced resin matrix composite material, high-strength steel, elastic gasket and other materials with excellent weather resistance and durability, which effectively improves the service life of the reinforcement system. Moreover, the anchor end seat, micro rod, column support and other structures are all detachable, which facilitates the later maintenance, repair and prestress adjustment.

[0034] It should be understood that the description in the Summary of the Invention is not intended to limit the key or essential features of the embodiments of the present invention, nor is it intended to restrict the scope of the invention. Other features of the invention will become readily apparent from the following description. Furthermore, implementation of any embodiment of the present invention does not imply the simultaneous possession or achievement of multiple or all of the aforementioned beneficial effects. Attached Figure Description

[0035] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0036] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0037] Figure 1 This is a schematic diagram of the installation of the quick-installation reinforcement system for the gable wall of an ultra-high steel structure factory building according to the present invention;

[0038] Figure 2 This is a schematic diagram of the overall structure of the existing wind-resistant truss of the present invention;

[0039] Figure 3 This is a schematic diagram of the connection between the existing wind-resistant truss and the wind-resistant column of the present invention;

[0040] Figure 4 This is a schematic diagram of the overall structure of the truss support and reinforcement component of the present invention;

[0041] Figure 5 This is a schematic diagram of the variable stiffness circular tube structure of the present invention;

[0042] Figure 6 This is a schematic diagram of the carbon fiber reinforced resin matrix composite layer of the present invention laid out in two ways;

[0043] Figure 7 This is a schematic diagram of the installation of the external prestressed reinforcement structure for the lower chord of the present invention;

[0044] Figure 8 This is a schematic diagram of the overall structure of the external prestressed reinforcement structure for the lower chord of the present invention;

[0045] Figure 9 This is a schematic diagram of the installation of the web member node reinforcement structure of the present invention;

[0046] Figure 10 This is a schematic diagram of the installation of the inter-column support structure of the present invention.

[0047] Marked in the image:

[0048] 1-Wind-resistant column;

[0049] 2-Wind-resistant truss; 201-Top chord; 202-Bottom chord; 203-Web member;

[0050] 3-Variable stiffness inclined support unit; 301-Variable stiffness circular tube; 302-Spherical hinge joint; 303-Connecting rod;

[0051] 4-Lower chord composite reinforcement structure; 401-Carbon fiber reinforced resin matrix composite layer;

[0052] 5-External prestressed reinforcement structure for the lower chord; 501-Anchorage end seat; 502-Prestressed tendon;

[0053] 6- Web member node reinforcement structure; 601- Micro rod;

[0054] 7-High-strength bolts;

[0055] 8-Inter-column bracing structure; 801-U-shaped steel;

[0056] 9-Adapter board;

[0057] 10 - Steel plate.

[0058] The same or corresponding marks in the diagram indicate the same or corresponding parts. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0060] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0061] It should be understood that the terms "comprising / including," "consisting of," or any other variations are intended to cover non-exclusive inclusion, such that a product, apparatus, process, or method that comprises a list of elements includes not only those elements but may also include, where necessary, other elements not expressly listed, or elements inherent to such a product, apparatus, process, or method. Without further limitation, an element defined by the phrases "comprising / including," "consisting of," does not exclude the presence of additional identical elements in the product, apparatus, process, or method that includes said element.

[0062] It should also be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device, component or structure referred to must have a specific orientation, be constructed or operated in a specific orientation, and should not be construed as a limitation of the present invention.

[0063] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0064] The implementation of the present invention will be described in detail below with reference to preferred embodiments.

[0065] See Figure 1 The present invention proposes a quick-installation reinforcement system for the gable walls of ultra-high steel structure factory buildings, which is adapted to the existing wind-resistant gable wall frame. The existing wind-resistant gable wall frame is the original load-bearing structure of the factory building, which includes wind-resistant columns 1 arranged at intervals along the span of the factory building, and wind-resistant trusses 2 bridging adjacent wind-resistant columns 1.

[0066] For details, see Figure 2 The wind-resistant truss 2 is composed of two upper chords 201, two lower chords 202 and several web members 203 connected together. The two upper chords 201 and the two lower chords 202 are arranged at intervals relative to each other. The web members 203 are arranged in a triangle between the upper chords 201 and the lower chords 202 and are connected to the upper chords 201 and the lower chords 202 respectively to form a box truss structure.

[0067] See Figure 3The connection between the wind-resistant truss 2 and the wind-resistant column 1 is the existing connection method of the existing structure of the factory building. The two use a transition plate 9 as a force transmission component. One side of the transition plate 9 abuts against the wind-resistant truss 2 and the other side abuts against the wind-resistant column 1. Each side is bolted and fixed to the wind-resistant truss 2 and the wind-resistant column 1 respectively by high-strength bolts 7.

[0068] In this embodiment, the adapter plate 9 is made of angle steel.

[0069] The quick-installation reinforcement system proposed in this invention is a newly added prefabricated reinforcement structure. It is fixed to the existing wind-resistant gable wall frame by bolting, without any welding or unloading of the existing wind-resistant truss. The core consists of truss support reinforcement components and truss reinforcement components. Without affecting the normal production of the factory, it can significantly improve the overall stiffness, lateral displacement resistance and nodal bearing capacity of the wind-resistant frame by rationally arranging the support system and precisely controlling the construction process. It also improves the stress concentration at the nodes, achieving efficient, safe and convenient reinforcement construction and meeting the engineering requirements for rapid reinforcement of ultra-high steel structure factory buildings.

[0070] See Figure 1 , Figure 4 The truss support reinforcement component is the outer support core structure of the quick-installation reinforcement system. It is located on the outer side of the existing wind-resistant truss 2 away from the gable wall. It includes multiple sets of variable stiffness diagonal support units 3. Each set is bolted and fixed to the upper chord 201 and the lower chord 202. Its core function is to enhance the overall support stiffness and anti-lateral displacement capacity of the existing wind-resistant truss 2, and form an integrated outer support system with the existing wind-resistant truss 2 to bear and disperse the lateral force brought by the horizontal wind load.

[0071] Furthermore, each set of variable stiffness inclined support units 3 includes two variable stiffness circular tubes 301, see [link to relevant documentation]. Figure 5 Each variable stiffness circular tube 301 adopts a variable stiffness structure with an end section larger than the middle section section. Increasing the end section can significantly improve the bending stiffness and local bearing capacity at the connection, effectively avoiding stress concentration and premature yielding in the node area; while reducing the middle section section can reduce the self-weight of the circular tube and the amount of material used while ensuring that the overall stiffness meets the design requirements, and facilitates processing, prefabrication and on-site installation.

[0072] One of the two variable stiffness circular tubes 301 is arranged obliquely, and one end of it is bolted to the upper chord 201. The other tube is arranged horizontally, and one end of it is bolted to the lower chord 202. The other ends of the two variable stiffness circular tubes 301 are connected to each other to form a stable right-angled triangular oblique support structure.

[0073] Furthermore, a steel plate 10 is pre-welded to one end of each variable stiffness circular tube 301 (the end that is bolted to the upper chord 201 or the lower chord 202). The steel plate 10 has pre-drilled bolt holes, which are convenient for fixing to the upper chord 201 and the lower chord 202 by passing high-strength bolts 7 through the corresponding bolt holes.

[0074] The other ends of the two variable stiffness circular tubes 301 are connected and fixed by a spherical hinge joint 302. Specifically, the spherical hinge joint 302 is a prefabricated integral component with insertion pipe sections in two directions. During installation, the other ends of the two variable stiffness circular tubes 301 are respectively fitted onto the outside of the insertion pipe sections, and then the ends of the circular tubes are clamped together by a split clamp (composed of two symmetrical semi-annular steel sleeves) and locked with high-strength bolts 7. This allows for a quick and rigid connection of the other ends of the two variable stiffness circular tubes 301 without welding, thus meeting the quick installation requirements of this invention.

[0075] Furthermore, adjacent variable stiffness inclined support units 3 are fixedly connected by connecting rods 303 along the length of the wind-resistant truss 2 using a bolted connection method, and multiple sets of right-angled triangles together form a continuous outer support belt.

[0076] The truss reinforcement assembly is a key structure for overall reinforcement of the weak areas of the lower chord 202 of the wind-resistant truss 2. It includes the lower chord composite reinforcement structure 4 and the lower chord external prestressed reinforcement structure 5. The lower chord composite reinforcement structure 4 can increase the bidirectional bending stiffness of the lower chord by 30% to 50%, effectively resisting bending deformation under the coupled action of strong horizontal winds and vertical loads. The lower chord external prestressed reinforcement structure 5 is used to actively apply prestress to offset part of the tensile stress, control the deformation of the lower chord 202, and improve its overall load-bearing capacity.

[0077] Specifically, the lower chord composite reinforcement structure 4 covers the outer surface of the lower chord 202 and extends to the outside of the connection node between the lower chord 202 and the web member 203, forming an overall wrapping reinforcement of the node area, which significantly improves the fatigue resistance and local bending and shear resistance of this part.

[0078] See Figure 6 The lower chord composite reinforcement structure 4 is formed by alternating laying and curing of multiple layers of carbon fiber reinforced resin matrix composite material layer 401 in two laying methods; one laying method is a 0° axial continuous wrapping laying along the length direction of the lower chord 202, and the other is a 90° circumferential interval clamping laying along the length direction of the lower chord 202 (similar to the interval binding of stirrups).

[0079] This alternating layering method fully leverages the synergistic reinforcement effect of the two types of layers: the 0° axial wrapping layer primarily bears the axial tensile and bending moment loads, significantly enhancing the bending and tensile bearing capacity of the lower chord 202; the 90° circumferential clamping layer provides effective lateral restraint to the member, limiting lateral deformation of the cross-section, inhibiting crack propagation, and improving local shear and fatigue resistance. The alternating arrangement of these two layers ensures overall load-bearing performance while avoiding the delamination and instability issues common with single-layer structures, making the composite reinforced structure and the original member work together more reliably and with more uniform stress distribution.

[0080] In this embodiment, the single-layer carbon fiber reinforced resin matrix composite layer 401 is made of unidirectional carbon fiber cloth with an areal density of 300 g / m² and a tensile strength of ≥3400 MPa, and is combined with bisphenol A type epoxy resin with a tensile strength of ≥80 MPa.

[0081] Each layer of carbon fiber reinforced resin matrix composite material 401 is bonded to the surface of the lower chord with an epoxy adhesive of 0.1–0.2 mm thickness. The surface of the lower chord is pre-treated with Sa2.5 grade sandblasting to remove rust and alcohol degreasing.

[0082] The thickness of the single-layer carbon fiber reinforced resin matrix composite material layer 401 is 3–5 mm, and the lower chord composite reinforcement structure 4 is formed by alternating layers of 8–12 of this composite material.

[0083] In practical implementation, the selection of the number of layers and the thickness of each layer mainly takes into account the reinforcement effect, construction performance, and bonding reliability: if the total thickness is too small, the improvement in stiffness and strength of the carbon fiber reinforcement layer is limited, and the reinforcement effect is not significant; if the total thickness is too large, problems such as uneven resin impregnation, weak interlayer bonding, and poor adhesion to the component surface are likely to occur. Using 8–12 layers alternately can improve the operability of the layering construction, enhance the adhesion between the composite reinforcement structure 4 of the lower chord and the surface of the lower chord 202, and make the force transmission more uniform.

[0084] Furthermore, the lower chord composite reinforcement structure 4 extends to cover the outside of the connection node between the lower chord 202 and the web member 203 by 150-200mm, ensuring continuous force transmission in the node area.

[0085] See Figure 7 The external prestressed reinforcement structure 5 of the lower chord is arranged in segments along the length of the lower chord 202, which can be adapted to lower chords 202 of different lengths and specifications, so as to realize segmented independent tensioning and construction control.

[0086] Each section has multiple prestressed tendons 502 uniformly anchored around the lower chord 202. By applying active prestress to the members, the tensile stress under working conditions is effectively offset, the deformation of the members is controlled, and the overall load-bearing capacity is improved.

[0087] This reinforcement structure can effectively control the excessive deformation of the wind-resistant truss 2 under extreme conditions such as strong winds and heavy loads, reduce the vertical deflection of the truss by 25% to 40%, significantly improve the overall stiffness and ultimate bearing capacity of the structure, and enhance the safety and durability of the structure under complex stress environments.

[0088] See Figure 7 , Figure 8 The external prestressed reinforcement structure 5 of the lower chord includes anchor end seats 501 and prestressing tendons 502. The anchor end seats 501 are detachably fixed to the lower chord 202 at predetermined intervals. There are four prestressing tendons 502, which are symmetrically arranged on the outer periphery of the lower chord 202. The two ends of each prestressing tendon 502 are anchored to the anchor end seats 501 respectively, and active prestress is applied to the lower chord 202 by tensioning.

[0089] Furthermore, the anchoring end seat 501 adopts a split clamping structure, consisting of two mating clamping units. The two clamping units are locked and fixed to the outside of the lower chord 202 by locking elements, thereby realizing the anchoring of the external prestressing tendons.

[0090] In one specific embodiment, the split clamping structure is a clamp-type prestressed sleeve, which is formed by two symmetrical C-shaped sleeves clamping together. The outer circumference of the C-shaped sleeve is integrally formed with a connecting flange, and bolt holes are correspondingly opened on the flange. The two semi-arc sleeves are clamped together and locked by bolts passing through the bolt holes.

[0091] Optionally, the C-type sleeve is made of Q235 steel (yield strength ≥235MPa), with an inner diameter that matches the size of the lower chord 202, a flange width of 80–100mm, and a bolt hole spacing of 100–120mm.

[0092] Optionally, a 5-8mm thick wear-resistant gasket is installed on the inner wall of the C-type sleeve. The wear-resistant gasket is made of polytetrafluoroethylene, which can not only prevent the steel sleeve from directly damaging the surface of the rod, but also reduce friction loss during tensioning and stress.

[0093] Optionally, the prestressing tendon 502 uses 1860MPa grade steel strand with a nominal diameter of 15.2mm and a tensioning control prestress value of 150–200kN. A plastic corrugated pipe with an inner diameter of 20–23mm (the inner diameter of the corrugated pipe is 5–8mm larger than the diameter of the steel strand) is sleeved on the outside of the steel strand. This can protect the prestressing tendon, reduce corrosion and friction loss, and ensure a smooth tensioning process to achieve stable transmission of prestress.

[0094] See Figure 1 , Figure 9The quick-installation reinforcement system proposed in this invention also includes a web member node reinforcement structure 6. The web member node reinforcement structure 6 includes micro rods 601, which are symmetrically arranged on both sides of the connection node between the web member 203 and the lower chord member 202. One end of the micro rod 601 is bolted to the flange of the web member 203 by a high-strength bolt 7, and the other end is also bolted to the flange of the lower chord member 202 by a high-strength bolt 7, forming a bidirectional limiting and cooperative support for the node.

[0095] The reinforcement structure 6 for the web member node can effectively optimize the stress state of the connection node between the web member 203 and the lower chord member 202, significantly reduce the stress amplitude of the welded intersection node by 40%-60%, effectively suppress the stress concentration phenomenon in the node area, avoid high-cycle fatigue failure of the node under cyclic stress such as strong wind load and heavy load, and greatly improve the structural robustness, shear resistance and fatigue resistance of the node.

[0096] Optionally, the micro-rod 601 is I-shaped and made of Q355 steel with a yield strength of not less than 345MPa. It has excellent tensile and shear resistance and can reliably bear the stress transmitted by the node. The diameter of the micro-rod 601 is preferably 20-25mm, and the length is customized according to the actual distance between the nodes of the web member 203 and the lower chord member 202 to ensure a tight fit with the node structure and effective stress bearing.

[0097] The microrod 601 is bolted together using grade 8.8 high-strength bolts. The bolt hole diameter is 1mm larger than the bolt diameter, which ensures the convenience and compatibility of bolt installation, and also enables a firm connection between the microrod 601 and the flange of the rod through the tightening action of the bolt, thereby improving the connection rigidity and force transmission efficiency.

[0098] Optionally, the micro rod 601 is provided with adapter plates 9 at both ends. One side of the adapter plate 9 abuts against the side wall of the micro rod 601, and the other side abuts against the flange of the lower chord 202. Each side is bolted and fixed to the micro rod 601 and the lower chord 202 by high-strength bolts 7.

[0099] Optionally, elastic gaskets (not shown in the figure) are provided at the end connection positions of micro rod 601 and web rod 203, as well as micro rod 601 and lower chord rod 202. Furthermore, the elastic gaskets are placed between the contact surfaces of adapter plate 9 and web rod 203, and adapter plate 9 and lower chord rod 202, which can effectively buffer the vibration and impact of the node under strong wind, heavy load and other working conditions, disperse local stress, and also play a role in sealing and corrosion prevention, and extend the service life of the connection structure.

[0100] Furthermore, the adapter plate 9 is made of angle steel.

[0101] Furthermore, the elastic gasket is a 3-5mm thick neoprene elastic gasket.

[0102] In this invention, the microrods 601 of the web member node reinforcement structure 6 are respectively set on both sides of the welded intersection node of the web member 203 and the lower chord member 202. The center distance of the bolt hole from the weld edge is controlled at 50-80mm. This arrangement can accurately act on the stress concentration area of ​​the welded intersection node, effectively optimize the stress state of the node, and significantly reduce the stress amplitude of the node.

[0103] In this invention, the reinforcement structure 6 of the web member node not only achieves a balance between ease of installation and reliable connection through the combination of high-strength bolts 7 and elastic washers, facilitating later inspection, maintenance and adjustment, but also forms a synergistic reinforcement system with the composite reinforcement structure 4 of the lower chord. By strengthening the nodes and enhancing the overall structure, the structural stability, durability and risk resistance of the entire wind-resistant truss 2 are improved, and the overall service life of the truss is extended.

[0104] See Figure 1 , Figure 10 The quick-installation reinforcement system proposed in this invention also includes a column support structure 8, which is arranged in an X-shape between longitudinally adjacent wind-resistant columns 1, and multiple sets are evenly arranged along the height direction of the wind-resistant columns 1. Both ends of each set of column support structures 8 are bolted and fixed to the corresponding wind-resistant column 1.

[0105] The inter-column bracing structure 8 significantly improves the overall lateral displacement resistance and structural stability of the wind-resistant column 1, preventing the wind-resistant column 1 from experiencing lateral displacement, bending deformation, or even instability and failure due to unilateral force or cyclic load.

[0106] Meanwhile, multiple sets of evenly distributed X-shaped cross-bracing structures can achieve uniform force transmission, disperse local stress concentration in wind-resistant columns 1, reduce damage caused by structural vibration, further enhance the overall rigidity and load-bearing reliability of the entire wind-resistant truss system, ensure that wind-resistant columns 1 can remain stable under extreme conditions such as strong winds and heavy loads, and provide solid support for the safe operation of the entire wind-resistant truss 2. At the same time, the bolted connection method takes into account both the convenience of installation and the flexibility of later inspection and maintenance. The support position and number can be adjusted according to the actual working conditions, improving the adaptability and practicality of the reinforcement system.

[0107] Furthermore, the inter-column support structure 8 adopts U200×70×7 type U-shaped steel 801. The U-shaped steel 801 is arranged in an X-shaped spatial intersection with the intersection angle controlled between 45° and 60°. The net distance between adjacent U-shaped steel 801 is not less than 50mm to avoid mutual interference.

[0108] Furthermore, the two ends of the inter-column support structure 8 are bolted to the wind-resistant column 1 through 16-20mm thick transition plates 9.

[0109] The specific structural form of the adapter plate 9 is not limited here. It can be flexibly selected according to the actual construction conditions, the size of the wind-resistant column connection part and the stress requirements. It can be the angle steel (such as L100×8 model) mentioned above, or a flat plate connection plate. As long as it can achieve reliable bolting between the column support structure 8 and the wind-resistant column 1 and meet the force transmission requirements, there is no need to uniformly limit its specific structural form, so as to adapt to the quick installation construction needs in different scenarios.

[0110] In this invention, at all locations where bolted connections are used (including the connection between the truss support reinforcement component and the wind-resistant truss 2, the connection between the micro rod 601 and the web member 203, the connection between the micro rod 601 and the lower chord member 202, and the connection between the inter-column support structure 8 and the wind-resistant column 1), a steel washer can be provided at the nut tightening end of the bolt to effectively prevent the bolt from loosening or slipping under long-term wind load vibration and alternating structural loads.

[0111] The present invention also proposes a construction method for the above-mentioned quick-installation reinforcement system, comprising the following steps:

[0112] Prefabrication preparation: Prefabricate in the factory the variable stiffness diagonal support unit 3 of the truss support and reinforcement component, the lower chord composite reinforcement structure 4 of the truss reinforcement and strengthening component, and the external prestressed reinforcement structure 5 of the lower chord.

[0113] In this step, the original wind-resistant truss 2 of the gable wall of the ultra-high steel structure factory building is first visually inspected. The focus is on checking the deformation, corrosion of the upper chord 201, lower chord 202, and web members 203 of the wind-resistant truss 2, as well as the weld defects at each node. At the same time, a total station is used to measure the planar displacement and vertical deflection of the wind-resistant truss 2. Based on the above inspection results, the number of carbon fiber reinforced resin matrix composite material layers 401 in the lower chord composite reinforcement structure 4 and the external prestress value parameters of the lower chord external prestressing reinforcement structure 5 are determined. Simultaneously, the variable stiffness diagonal support unit 3, the lower chord composite reinforcement structure 4, and the lower chord external prestressing reinforcement structure 5 are processed and customized. All structures are prefabricated in the factory in a standardized manner to ensure that the component dimensions and specifications are consistent with the design requirements. After anti-corrosion treatment, they are transported to the construction site to meet the needs of on-site rapid assembly construction.

[0114] Truss support reinforcement: Variable stiffness diagonal support units 3 are arranged on the outer side of the wind-resistant truss 2 away from the gable wall. The two ends of each variable stiffness diagonal support unit 3 are respectively bolted and fixed to the upper chord 201 and lower chord 202 of the wind-resistant truss 2.

[0115] In this step, each set of variable stiffness inclined support units 3 adopts a triangular structure arrangement, especially a right-angled triangular structure. Both of its variable stiffness circular tubes 301 have variable cross-sections at the ends that are larger than those in the middle. One of the variable stiffness circular tubes 301 is arranged obliquely, and one end of it is bolted to the upper chord 201. The other variable stiffness circular tube 301 is arranged horizontally, and one end of it is bolted to the lower chord 202. The other ends of the two variable stiffness circular tubes are connected to each other to form a stable triangular support structure.

[0116] Truss reinforcement: Multiple layers of carbon fiber reinforced resin matrix composite material 401 are alternately laid on the outer surface of the lower chord 202 in two laying methods, so that they cover the outer surface of the lower chord 202 and extend to the outside of the connection node between the lower chord 202 and the web member 203.

[0117] Meanwhile, external prestressing tendons are laid out in sections along the length of the lower chord 202, and the two ends of the prestressing tendons 502 are anchored to the anchoring end seats 501 of the wind-resistant column 1. They are tensioned and locked in stages according to the design prestress value to achieve active prestressing reinforcement of the lower chord 202.

[0118] In this step, the outer surface of the lower chord 202 is first sandblasted to remove rust until it reaches the Sa2.5 standard, and then wiped with alcohol to degrease it. After the surface is completely dry, epoxy adhesive is evenly applied to it. Then, according to the designed number of layers, the carbon fiber reinforced resin matrix composite layer 401 is laid alternately using a 0° axial continuous wrapping method and a 90° circumferential interval clamping method. During the laying process, a scraper is used to evenly apply the resin and remove air bubbles between the carbon fiber cloth and the surface of the lower chord to ensure a tight bond between the two. After each layer is laid, it is left to stand for 2-3 hours to cure. After the final layer is laid, a curing membrane is applied and the entire structure is cured for 7 days. After curing, external prestressing tendons are laid out in sections along the length of the lower chord 202. The two ends of the prestressing tendons 502 are anchored to the pre-set anchoring end seats 501 on the wind-resistant column 1. Then, tensioning equipment is used to tension the tendons in stages according to the design prestress value (150-200kN). Each stage of tensioning is held for no less than 5 minutes. After tensioning, the anchoring device is locked in time, thereby applying active prestress to the lower chord 202. This, together with the composite reinforcement structure formed by the covering, achieves a dual reinforcement effect combining passive and active reinforcement.

[0119] Furthermore, the method also includes reinforcement of the web member nodes: a stress detector is used to detect the stress value of the connection node between the lower chord 202 and the web member 203, and the layout position, quantity and specifications of the micro-rods 601 are determined based on the test results to ensure that the micro-rod supports can specifically offset the stress concentration at the node and further improve the load-bearing capacity of the node.

[0120] In this step, holes are drilled at the design points on the flanges of the web members and the lower chord members on both sides of the welding joint between the web member 203 and the lower chord member 202. The diameter of the holes is 1 mm larger than that of the high-strength bolts 7. Adapter plates 9 are installed at both ends of the micro rod 601, and bolt holes with the same position and diameter as the holes in the flanges of the members are opened on the adapter plates 9. The high-strength bolts 7 are then passed through the bolt holes of the adapter plates 9, the micro rod 601, and the corresponding flanges of the members in sequence, and tightened with a torque wrench to a torque of 300–350 N·m to complete the assembly installation of the micro rod support.

[0121] Furthermore, the method also includes the construction of inter-column support structures: inter-column support structures 8 arranged in an X-shape are installed between longitudinally adjacent wind-resistant columns 1, and multiple sets are evenly distributed along the height direction of the wind-resistant columns 1. Both ends of each set of inter-column support structures 8 are bolted and fixed to the corresponding wind-resistant columns 1 to form an overall lateral force resisting system.

[0122] In this step, both ends of the X-shaped U-shaped steel 801 are bolted to the corresponding wind-resistant columns 1 using adapter plates 9. Specifically, first, the installation position of one side of the adapter plate 9 corresponding to the end of the U-shaped steel 801 is bolted to the wind-resistant column 1 using high-strength bolts 7. Then, the two ends of the X-shaped U-shaped steel 801 are aligned with the other side of one adapter plate 9, and the high-strength bolts 7 are inserted and initially tightened. After adjusting the cross angle of the U-shaped steel 801 to 45°~60° and the cross clearance to not less than 50mm to meet the design requirements, the bolts are tightened with a torque wrench to a torque of 250~300N・m to complete the fixing of the inter-column support.

[0123] Furthermore, the method also includes post-reinforcement inspection and acceptance: the plane displacement and vertical deflection of the wind-resistant truss 2 are re-measured using a total station, and the stress changes of the lower chord 202 and web member 203 nodes are detected using a stress detector to confirm that all mechanical indicators meet the design requirements; at the same time, the installation quality of all reinforcement components is checked, including the integrity of the composite material layer, the tightness of the micro-rod supports, the sealing of the prestressed sleeves, and the bolt torque of each connection node. After all are qualified, the overall construction acceptance is completed.

[0124] This construction method involves factory prefabrication and on-site assembly with bolted connections. The entire process requires no hot work or unloading of the existing structure and can be implemented under normal factory conditions. By combining triangular variable stiffness supports, carbon fiber composite reinforcement, and external prestressed active reinforcement, along with micro-rod reinforcement at web nodes and X-shaped inter-column supports, the overall stiffness, bending capacity, and lateral displacement resistance of the wind-resistant truss are significantly improved. This effectively addresses the problem of stress concentration at nodes, enhances the stability and durability of the gable wind-resistant frame under strong wind loads, and allows for quick construction and convenient maintenance, making it suitable for the rapid reinforcement needs of ultra-high steel structure factory buildings.

[0125] Engineering Examples

[0126] This embodiment describes the specific implementation of the quick-installation reinforcement system for the gable walls of ultra-high steel structure factory buildings described in this invention. A detailed explanation is provided using the existing wind-resistant frame of the gable wall of an ultra-high steel structure factory building with an eave height of 45m and a total span of 24m for the two wind-resistant trusses as an example. It should be understood that the scope of application of this invention includes, but is not limited to, this specific size and condition, and it can be adapted to similar ultra-high steel structure factory buildings with different eave heights and truss spans according to actual engineering needs.

[0127] I. Project Overview

[0128] In this embodiment, the existing gable wall wind-resistant frame includes wind-resistant columns 1 (using H600 I-beams) spaced 12m apart along the span of the factory building, and wind-resistant trusses 2 bridging adjacent wind-resistant columns 1. The wind-resistant trusses 2 and wind-resistant columns 1 are connected by L100×8 Q355 angle steel as transition plates 9 and are fixed by M24×80 10.9 grade high-strength bolts. The wind-resistant trusses 2 are arranged in two layers at heights of 20m and 40m in the factory building. Each layer of the wind-resistant trusses 2 consists of two upper chord members 201 (using H400 I-beams), two lower chord members 202 (using H400 I-beams, with a horizontal spacing of 4m), and web members 203 (using H300 I-beams, triangularly connected) forming a box-shaped structure, which is the core component of the gable wall resisting the coupling effect of horizontal wind loads and vertical loads.

[0129] The factory is located in a typhoon-prone area, experiencing 2-3 strong typhoons annually. Due to the long-term exposure to strong wind loads, the original wind-resistant truss has shown obvious stress hazards: preliminary inspections revealed that the lower chord 202 is bent and deformed, with a maximum vertical deflection of 15mm, and there is a risk of cracking at the weld joints of the web members. Therefore, it is necessary to use the quick-installation reinforcement system for the gable walls of ultra-high steel structure factory buildings of this invention for quick-installation reinforcement.

[0130] II. Specific Implementation Steps

[0131] (1) Construction preparation and preliminary testing

[0132] 1. Appearance and Deformation Inspection: In accordance with the prefabrication preparation steps of the construction method of this invention, a total station was used to comprehensively measure the two-layer wind-resistant truss 2. The maximum vertical deflection of the lower chord 202 was accurately recorded as 15mm (exceeding the design limit by 10mm), and the planar displacement was 3mm (meeting the design limit). An ultrasonic flaw detector was used to inspect the welding joints of the web member 203 and the lower chord 202. Three welds were found to have secondary defects (incomplete fusion length ≤10mm), which are all potential welding hazards in the existing structure and need to be controlled simultaneously during the reinforcement process. At the same time, a combination of visual inspection and total station-assisted measurement was used to inspect the connection parts of the upper chord 201 and lower chord 202 on the outer side of the wind-resistant truss 2 (away from the gable wall). Some bolts at the connection joints were found to be slightly loose (insufficient torque).

[0133] Through the above tests, the system can systematically identify defects such as excessive deformation, weld defects, and weak node connections in existing wind-resistant trusses. This provides a direct basis for the subsequent arrangement of truss support reinforcement components, the material selection and parameter design of truss reinforcement components, and also provides benchmark comparison data for the structural reset effect, load-bearing capacity recovery, and overall safety acceptance after reinforcement. This enables the correspondence and closed-loop control between defect diagnosis, reinforcement design, and effect verification.

[0134] 2. Stress Testing: Using resistance strain gauges (corresponding to the stress testing instrument described in this invention), the mid-span stress value of the lower chord 202 was measured to be 180 MPa (design limit 210 MPa). Although it did not exceed the limit, it was close to the critical value. The stress amplitude at the web member node was 80 MPa, far exceeding the fatigue safety limit, which could easily lead to fatigue failure of the node, consistent with the original design intention of the web member node reinforcement structure of this invention. Simultaneously, the stress distribution in the corresponding connection areas of the upper chord 201 and lower chord 202 on the outside of the wind-resistant truss 2 was tested. It was found that the stress transmission in this area was uneven and there was local stress concentration. This further indicates that the original support on the outside of the wind-resistant truss 2 was insufficient, and it is urgent to disperse the stress and improve the overall stability by using truss support reinforcement components.

[0135] 3. Parameter Determination and Component Prefabrication: Based on the above test results and in conjunction with the design requirements of the truss support reinforcement component, truss reinforcement component, and web member node reinforcement structure of this invention, the parameters of the truss support reinforcement component are determined as follows: Each group of variable stiffness diagonal support unit 3 is equipped with two variable stiffness circular tubes 301 (the end section is larger than the middle section to meet the stress requirements of the wind-resistant truss 2). The spherical hinge joint 302 adopts a factory-prefabricated integrated component. The connecting rod 303 adopts a material specification that matches the variable stiffness circular tube to ensure bolting compatibility with the upper chord 201 and lower chord 202 of the wind-resistant truss 2. Furthermore, it is determined that the carbon fiber reinforced resin matrix composite material layer 401 in the lower chord composite reinforcement structure 4 is laid in 10 layers (single layer thickness 4mm, total thickness 40mm), and the tension control prestress value of the lower chord external prestress reinforcement structure 5 is 180kN (within the design range of 150-200kN of this invention). Meanwhile, the micro-rods 601 of the web member node reinforcement structure 6 are arranged with 2 rods (22mm in diameter, suitable for Q355 steel material requirements) at each node.

[0136] All reinforcement components are prefabricated in the factory according to standardization, including the variable stiffness circular tube 301 of the variable stiffness inclined support unit 3, the carbon fiber reinforced resin matrix composite layer 601, the clamp-type prestressed sleeve, the micro rod 601, the L100×8 angle steel adapter plate, the U200×70×7 type U-shaped steel, the spherical hinge joint 302, the connecting rod 303, etc. After the prefabrication is completed, the quality of the components is strictly inspected to ensure that the tensile strength of the carbon fiber cloth, the dimensional deviation of the micro rod, the flange size of the prestressed sleeve, the cross-sectional size of the variable stiffness circular tube, etc. all meet the design requirements of this invention. After anti-corrosion treatment, they are transported to the construction site to meet the needs of quick installation construction.

[0137] (2) Installation of truss support reinforcement components

[0138] Specifically as follows:

[0139] 1. Installation of variable stiffness diagonal support unit: The variable stiffness diagonal support unit 3 is arranged on the outer side of the wind-resistant truss 2 away from the gable wall. The two variable stiffness circular tubes 301 of each variable stiffness diagonal support unit are arranged according to the design position. One of them is arranged diagonally, with one end aligned with the corresponding connection position of the upper chord 201. The other is arranged horizontally, with one end aligned with the corresponding connection position of the lower chord 202. M24×80 grade 10.9 high-strength bolts (consistent with the specifications of the bolts at the nodes of the wind-resistant truss) are used to bolt and fix them to the upper chord 201 and the lower chord 202 respectively. The bolt tightening torque is controlled at 380 N·m, and tightened in three stages (initial tightening 150 N·m, secondary tightening 250 N·m, and final tightening 380 N·m) to ensure a firm connection.

[0140] 2. Unit connection and fixing: The other ends of the two variable stiffness circular tubes 301 are connected and fixed through the ball joint 302. The end of the circular tube is sleeved on the outside of the insertion pipe section of the ball joint 302. The ends of the circular tube are clamped together with a split clamp and locked with high-strength bolts to achieve a quick connection without welding. Then, the adjacent variable stiffness inclined support units 3 are bolted and fixed along the length of the wind-resistant truss 2 through the connecting rod 303. The bolt tightening torque is controlled at 350 N·m to form a continuous outer support belt, which forms an integrated outer support system with the existing wind-resistant truss 2.

[0141] (3) Construction of carbon fiber reinforced resin matrix composite layer of lower chord

[0142] Specifically as follows:

[0143] 1. Surface pretreatment: Use sandblasting equipment to remove rust from the surface of the lower chord 202 until it reaches the Sa2.5 standard (no visible grease, dirt, oxide scale, rust, etc. residue ≤5%). Wipe the surface with alcohol to thoroughly remove dust and oil, and let it dry for 2 hours to ensure that the surface of the lower chord meets the bonding requirements.

[0144] 2. Adhesive application and fabric laying: Apply a 0.15mm thick epoxy adhesive (tensile strength ≥80MPa) using a scraper to spread it evenly, ensuring no missed areas or accumulation. Lay 10 layers of carbon fiber reinforced resin-based composite material as designed, using alternating 0° axial continuous wrapping and 90° circumferential clamping methods as described in this invention. The first layer is laid along the length of the lower chord 202, and subsequent layers are laid alternately with the direction adjusted (90° to the previous layer). During the laying process, use a roller to remove air bubbles to ensure a tight bond between the fabric and the adhesive, without any hollow areas or wrinkles. After each layer is laid, allow it to stand for 2.5 hours for curing, which meets the 2-3 hour curing requirement of this invention.

[0145] 3. Curing: After the last layer is laid, cover it with a polyethylene curing film and cure it for 7 days at 25℃ and 60% relative humidity. During the curing period, collisions and loads are strictly prohibited to ensure that the composite material layer is cured and formed.

[0146] 4. Quality inspection: After curing, visual inspection is performed to check that there are no hollow areas or cracks on the surface of the composite material layer. The bonding quality is tested using an ultrasonic testing instrument. The hollow area is ≤5%, which meets the reinforcement quality requirements of this invention.

[0147] (4) Installation of external prestressed reinforcement structure for lower chord

[0148] Specifically as follows:

[0149] 1. Anchorage end seat installation: Two anchorage end seats form a group, with a 5-meter interval between adjacent groups. Each group is anchored to the lower chord 202 with a length of 1 meter. Specifically, each anchorage end seat includes two clamp-type prestressed sleeves (Q235 steel material, inner diameter adapted to H400 I-beam flange, flange width 90mm, within the 80-100mm range of this invention). The two clamp-type prestressed sleeves are fitted onto the outer side of the lower chord 202 in the main force direction, aligned with the bolt holes on the flange (hole diameter 20mm, spacing 110mm, meeting the 100-120mm requirement of this invention), and M18×60 grade 8.8 high-strength bolts are inserted and tightened to a torque of 250 N·m, ensuring that the sleeves are tightly fitted to the lower chord flange and that the 5mm thick PTFE wear-resistant gasket on the inner wall does not shift, thus providing protection and friction reduction.

[0150] 2. Installation and tensioning of prestressing tendons: 1860MPa grade steel strands (nominal diameter 15.2mm, meeting the requirements of this invention) are passed through a plastic corrugated pipe with an inner diameter of 22mm (6.8mm larger than the diameter of the steel strands, within the range of 5-8mm) and anchored to the anchor end. Both ends of the corrugated pipe are sealed to the anchor end to prevent corrosion. A through-type tensioning device is used for graded tensioning, with tensioning grades of 50kN (holding load for 5 minutes) → 100kN (holding load for 5 minutes) → 150kN (holding load for 5 minutes) → 180kN (holding load for 10 minutes). The holding time for each tensioning grade is not less than 5 minutes as required by this invention. During the tensioning process, the deformation of the lower chord 202 is monitored in real time to ensure uniform deformation.

[0151] 3. Locking and anchoring: After tensioning to the design value of 180kN, tighten the anchoring wedges, cut off the excess steel strands (leaving a length of 150mm), and apply anti-corrosion coating to the anchoring end to complete the installation of the external prestressed reinforcement structure.

[0152] (5) Micropole installation

[0153] Specifically as follows:

[0154] 1. Drilling and positioning: According to the design position, drill holes on the flange of the web member and the flange of the lower chord member using a magnetic drill. The hole diameter is 23mm (suitable for M22 high-strength bolts, 1mm larger than the bolt diameter, which meets the design requirements of this invention). The center distance of the bolt hole from the weld edge is 60mm (within the range of 50-80mm in this invention), ensuring that the drilling position deviation is ≤2mm.

[0155] 2. Component installation: Lay 4mm thick neoprene rubber elastic gaskets (meeting the 3-5mm thickness requirement of this invention) at both ends of the micro rod 601 (Q355 steel, 22mm diameter, 300mm length, I-shaped cross section). Pass M22×50 grade 8.8 high-strength bolts through the bolt holes of the adapter plates 9 (angle steel) at both ends of the micro rod 601, the web rod 203 and the lower chord rod 202 in sequence to ensure accurate connection alignment.

[0156] 3. Bolt tightening: Use a torque wrench to tighten the bolts to a torque of 320 N·m (within the range of 300-350 N·m of this invention), tightening in two stages (tighten to 200 N·m the first time, let stand for 10 minutes, and then tighten to 320 N·m) to ensure that the microrod and the flange of the rod are tightly fitted together.

[0157] 4. Acceptance: Check the fit between the micro rod 601 and the web rod 203 and the lower chord rod 202. Use a feeler gauge to check that the gap is ≤0.5mm and the bolt torque deviation is ≤±5%. If the fit meets the installation quality requirements of this invention, the assembly installation of the micro rod support point is completed.

[0158] (6) Installation of inter-column bracing structure

[0159] Specifically as follows:

[0160] 1. Installation of adapter plate 9: Install an 18mm thick Q355 steel adapter plate (within the range of 16-20mm in this invention) on the outer side of the wind-resistant column flange. The adapter plate 9 is fixed to the wind-resistant column 1 by M20 high-strength bolts with a bolt torque of 280 N·m.

[0161] 2. U-shaped steel adjustment: Align both ends of the U200×70×7 Q235 U-shaped steel with the adapter plate 9, and arrange them in an X-shaped spatial cross arrangement as required by this invention. Adjust the cross angle to 50° (within the range of 45°-60°). The net distance between adjacent U-shaped steels 801 should be 60mm (not less than 50mm) to avoid mutual interference.

[0162] 3. Bolt fixing: Insert M16×50 grade 8.8 high-strength bolts and tighten them to a torque of 280 N·m (within the range of 250-300 N·m of this invention) to ensure that the U-shaped steel 801 and the adapter plate 9 are tightly fitted, thus completing the installation of the inter-column support structure and forming an overall lateral force resisting system.

[0163] (7) Post-reinforcement inspection and acceptance

[0164] Specifically as follows:

[0165] 1. Deformation detection: The maximum vertical deflection of the lower chord 202 of the wind-resistant truss 2 was measured using a total station and found to be 6mm, which is less than the design limit of 10mm and 60% lower than before reinforcement, meeting the deflection control requirements of the truss reinforcement structure of this invention; the planar displacement was 2mm, which meets the design limit, and the deformation of the wind-resistant truss was effectively controlled; the deformation of the truss support reinforcement components was detected simultaneously, and there was no displacement or bending, and the outer support strip was flat overall, meeting the design requirements.

[0166] 2. Stress testing: The stress value at the mid-span of the lower chord 202 was measured using resistance strain gauges and found to be 120 MPa, a decrease of 33.3% compared to before reinforcement; the stress amplitude at the web member node was 35 MPa, a decrease of 56.25% compared to before reinforcement. The reduction achieved the design effect of 40%-60% for the web member node reinforcement structure of this invention, and the fatigue risk of the node was significantly reduced; the stress distribution in the outer support area of ​​the wind-resistant truss 2 was tested, and the stress transmission was uniform with no obvious stress concentration. The stress of the truss support reinforcement components met the design expectations.

[0167] 3. Component quality acceptance: Check that the carbon fiber composite material layer has no hollow areas or cracks, and that the bonding quality is qualified; the torque deviation of the micro-rod bolts is ≤3%, which meets the requirements; the prestressed sleeve is well sealed, with no loosening or leakage; the bolt torque and connection gap of the truss support reinforcement component meet the design requirements of this invention, and the spherical hinge joint and connecting rod are firmly connected; the bolt torque of all connection nodes meets the design requirements of this invention, and the steel pads and elastic washers are installed in place.

[0168] 4. Overall Acceptance: Issue a reinforcement construction acceptance report. All indicators meet the requirements of the "Standard for Steel Structure Reinforcement Design" (GB51367-2019) and the design requirements of this project. They also conform to the various performance indicators of the quick-installation reinforcement system of this invention. The acceptance is qualified, and the overall reinforcement construction is completed.

[0169] III. Implementation Results

[0170] After applying the quick-installation reinforcement system described in this invention, the construction period for this project was reduced to only 20 days, shortening it by more than 55% compared to traditional welding reinforcement processes (over 45 days). The entire construction process involved no open flame work and required no unloading of the existing structure, allowing for parallel reinforcement construction and factory production without any impact on daily operations. Subsequent field testing under typhoon conditions with a maximum wind speed of 35 m / s demonstrated that the vertical deflection of the lower chord of the reinforced wind-resistant truss was consistently controlled within 8 mm, and no new stress concentration was observed at the web member connection nodes. Practice has proven that this technology can effectively and significantly improve the structural safety reserve and overall stability, achieving the expected reinforcement effect.

[0171] It will be readily understood by those skilled in the art that, without conflict, the above-mentioned preferred solutions can be freely combined and superimposed.

[0172] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A quick-installation reinforcement system for the gable wall of an ultra-high steel structure factory building, characterized in that, The system is adapted to existing gable wall wind-resistant frames, which include wind-resistant columns and wind-resistant trusses spanning the wind-resistant columns. The wind-resistant trusses are formed by connecting upper chords, lower chords, and web members. The quick-installation reinforcement system includes: A truss support and reinforcement assembly, located on the outer side of the wind-resistant truss away from the gable wall, includes: Multiple sets of variable stiffness diagonal support units, each set of which is bolted and fixed to the corresponding upper and lower chord members, are used to enhance the overall support stiffness and lateral displacement resistance of the wind-resistant truss; and Truss reinforcement and strengthening components, including: A composite reinforcement structure for the lower chord is wrapped around the outer surface of the lower chord and extends to the outside of the connection node between the lower chord and the web member, in order to improve the bending stiffness of the lower chord. The external prestressed reinforcement structure for the lower chord is arranged in segments along the length of the lower chord, and each segment has multiple prestressed tendons anchored circumferentially along the lower chord to apply active prestress to the lower chord.

2. The quick-installation reinforcement system according to claim 1, characterized in that, The wind-resistant truss is composed of two upper chords, two lower chords, and several web members. The two upper chords and the two lower chords are arranged at intervals relative to each other. The web members are arranged in a triangle between the upper chords and the lower chords and are connected to the upper chords and the lower chords respectively to form a box truss structure.

3. The quick-installation reinforcement system according to claim 1, characterized in that, Each set of variable stiffness inclined support units is a triangular structure, including two variable stiffness circular tubes. One of the two variable stiffness circular tubes is arranged obliquely, and one end of it is bolted to the upper chord. The other tube is arranged horizontally, and one end of it is bolted to the lower chord. The other ends of the two variable stiffness circular tubes are connected to each other. The end section of each variable stiffness circular tube is larger than its middle section section.

4. The quick-installation reinforcement system according to claim 1, characterized in that, The lower chord composite reinforcement structure is formed by alternating laying and curing of multiple layers of carbon fiber reinforced resin matrix composite material in two laying methods. One laying method is a 0° axial continuous wrapping laying along the length of the lower chord, and the other is a 90° circumferential spaced clamp laying along the length of the lower chord.

5. The quick-installation reinforcement system according to claim 4, characterized in that, The carbon fiber reinforced resin matrix composite layer is made of carbon fiber cloth and bisphenol A type epoxy resin.

6. The quick-installation reinforcement system according to claim 1, characterized in that, The composite reinforcement structure of the lower chord extends to cover the outside of the connection node between the lower chord and the web member by 150-200mm.

7. The quick-installation reinforcement system according to claim 1, characterized in that, The external prestressed reinforcement structure for the lower chord includes: An anchoring end seat, which is detachably fixed to the lower chord at predetermined intervals; Four prestressing tendons are arranged symmetrically along the circumference of the lower chord. The two ends of each prestressing tendon are anchored to the anchorage, and active prestress is applied to the lower chord by tensioning.

8. The quick-installation reinforcement system according to claim 7, characterized in that, The anchoring end seat adopts a split clamping structure, which consists of two mating clamping units. The two clamping units are locked and fixed to the outside of the lower chord by locking members to achieve anchoring of the external prestressing tendons.

9. The quick-installation reinforcement system according to claim 1, characterized in that, It also includes a web member node reinforcement structure, which includes: Microrods, symmetrically arranged on both sides of the connection node between the web member and the lower chord, wherein the two ends of the microrods are respectively bolted and fixed to the web member and the lower chord by high-strength bolts; and / or, It also includes column support structures, which are arranged in an X-shape between longitudinally adjacent wind-resistant columns, and multiple sets are evenly arranged along the height direction of the wind-resistant columns. Both ends of each set of column support structures are bolted and fixed to the corresponding wind-resistant column.

10. A construction method for a quick-installation reinforcement system according to any one of claims 1 to 9, characterized in that, Includes the following steps: Prefabrication preparation: Prefabricate in the factory the variable stiffness diagonal support unit of the truss support and reinforcement component, the lower chord composite reinforcement structure of the truss reinforcement and strengthening component, and the external prestressed reinforcement structure of the lower chord. Truss support reinforcement: Variable stiffness diagonal support units are arranged on the outer side of the wind-resistant truss away from the gable wall, and the two ends of each variable stiffness diagonal support unit are respectively bolted and fixed to the upper chord and lower chord of the wind-resistant truss. Truss reinforcement: Multiple layers of carbon fiber reinforced resin matrix composite material are alternately laid on the outer surface of the lower chord in two laying methods, so that they cover the outer surface of the lower chord and extend to the outside of the connection node between the lower chord and the web members; at the same time, external prestressing tendons are laid in sections along the length of the lower chord, and the two ends of the prestressing tendons are anchored to the anchoring device of the wind-resistant column. The tendons are tensioned and locked in stages according to the design prestress value to achieve active prestressing reinforcement of the lower chord.

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