Construction method of large-span glass curtain wall with through-core pull rod composite frame

Abstract

The application provides a kind of through-core pull rod composite frame large-span glass curtain wall construction method, belongs to glass curtain wall construction technical field, mainly includes two major links of production and installation.Production link adopts cold and hot extrusion process to produce right-angle flat section rectangular tube, obtains the required component by annealing, cold extrusion forming and local hot extrusion treatment.Installation link first carries out pull rod system construction deepening design, decomposes through-core pull rod into intersegment pull rod, and determines the beam pre-arch value through simulation analysis.Then, on-site construction is carried out, and steps such as column installation adjustment, large-span beam hoisting positioning, intersegment pull rod assembly connection, midspan hoisting column installation and welding are completed in turn.Finally, the pull rod system is tensioned by using the cross-shaped tensioning tool, and the installation of glass panel and decoration system is completed, so as to ensure the construction quality and structural safety of large-span glass curtain wall system, and solve the technical problems that the traditional method excessively relies on manual experience, lacks scientific theoretical guidance and accurate control means.

Description

Technical Field

[0001] This invention belongs to the field of glass curtain wall construction technology, and specifically relates to a construction method for a large-span glass curtain wall with a through-core tie rod composite frame. Background Technology

[0002] Currently, the support system for large-span glass curtain walls mainly adopts a steel frame structure, comprising three core components: columns, beams, and tie rods. Among these, the columns, as the primary load-bearing components, must meet stringent stiffness and stability requirements; the beams, typically spanning 8 to 12 meters, primarily bear the weight of the glass panels and wind loads; and the tie rods enhance the overall stability of the frame and provide auxiliary load-bearing support. However, in actual construction, traditional experience-based construction methods face numerous technical bottlenecks and challenges.

[0003] First, the method of determining the pre-camber value of crossbeams based on human experience has significant uncertainties. Construction workers often rely on past experience and simple calculations to determine the pre-camber value, which cannot accurately predict the deformation state of the structure at each construction stage. This experience-based approach makes it difficult to control the final straightness of the crossbeams and easily leads to problems of excessive or insufficient deformation. Especially in large-span projects with spans exceeding 10 meters, it is difficult to accurately grasp the geometric nonlinear effects of the structure based solely on experience, resulting in potential construction quality hazards.

[0004] Secondly, the determination and control of the tension force in the tie rod system mainly relies on the subjective judgment of the construction personnel. Traditional construction lacks scientific tension force calculation models and precise control methods, often employing a "trial and error" approach to adjust the tension force. This approach is not only inefficient but may also lead to uneven stress distribution in the tie rod system, affecting the overall structural performance. Furthermore, due to a lack of accurate understanding of the stress distribution at the joints, construction personnel find it difficult to determine whether the stress state of each connection joint is safe during tensioning.

[0005] Third, the geometric accuracy control of composite frames relies excessively on manual measurement and adjustment. In traditional construction, key parameters such as the verticality of columns, the horizontality of beams, and the collinearity of tie rods are mainly ensured through manual verification. This method is not only labor-intensive but also results in unstable accuracy control. Especially during the installation of the frame system, there are complex positional interference relationships between the components, making it difficult to achieve high-precision spatial positioning based solely on experience.

[0006] Furthermore, the assessment of the stress performance of joint structures lacks scientific basis. Construction personnel often rely on experience to judge the rationality of the joint structure, lacking quantitative analysis of the joint stiffness characteristics. This qualitative assessment method makes it difficult to ensure the reliability of joint design and increases potential structural safety hazards. At the same time, due to a lack of in-depth understanding of the mechanical properties of materials, construction personnel find it difficult to accurately grasp the impact of welding process parameters on joint strength.

[0007] The root of these technical problems lies in the fact that traditional construction methods rely excessively on manual experience, lacking scientific theoretical guidance and precise control methods. As building curtain walls develop towards larger spans and higher precision, there is an urgent need to establish a construction process system based on mechanical theory and precise calculations, realizing a shift from "experience-based" to "scientific" methods. This is not only related to improving project quality but also an inevitable requirement for promoting the technological advancement of large-span glass curtain walls. Summary of the Invention

[0008] In view of this, the present invention provides a construction method for large-span glass curtain walls with through-core tie rod composite frames, which can solve the technical problems of traditional construction methods that rely too much on manual experience and lack scientific theoretical guidance and precise control methods.

[0009] This invention is implemented as follows:

[0010] This invention provides a construction method for a large-span glass curtain wall with a through-core tie-rod composite frame, comprising the following steps:

[0011] S10. A right-angled flat-section rectangular tube is manufactured using cold extrusion and hot extrusion processes. The manufacturing of the right-angled flat-section rectangular tube includes annealing the substrate, cold extruding the annealed substrate to form a rounded-corner rectangular tube, and locally heating and hot extruding the rounded-corner rectangular tube to form sharp corners.

[0012] S20. Conduct detailed construction design for the curtain wall through-core tie rod system, decompose the through-core tie rod system into inter-segment tie rods, install through-core threaded rods on the horizontal beams, clamp the horizontal beams with upper and lower washers, and connect the inter-segment tie rods to the through-core threaded rods through tension sleeves;

[0013] S30. Simulate and analyze the entire construction and installation process of the large-span glass curtain wall system, determine the pre-camber value of the large-span horizontal beam construction, and formulate a horizontal beam construction control table.

[0014] S40. Install the column and fix the column top pin and column body pin, and adjust the verticality and normal angle of the column.

[0015] S50. Large-span crossbeams are hoisted using an adjustable chain hoist. The adjustable chain hoist is set at the 3-point position of the crossbeam and the horizontal state and pre-camber value of the crossbeam are controlled by the adjustable chain hoist.

[0016] S60. Install the inter-section tie rod, pass the through-hole screw through the pre-drilled hole of the crossbeam and lock the crossbeam with the upper and lower washers, and connect the inter-section tie rod to the through-hole screw through the tension sleeve;

[0017] S70. Repeat steps S50 to S60 to complete the installation of the single-span beam and tie rod system, install the mid-span hanging column and complete the welding of the beam and column according to the design requirements.

[0018] S80. The tie rod system is tensioned using a grid-shaped tensioning fixture. The grid-shaped tensioning fixture is fitted onto the upper and lower crossbeams. The fixture is pressed onto the crossbeams by a hydraulic jack and the tensioning sleeve is tightened simultaneously.

[0019] S90. Install glass panels and decorative systems, including installing keel connectors, applying topcoat, and installing glass panels and decorative panels.

[0020] The following equations are required to limit the relevant parameters in this construction method:

[0021] 1. Geometric relationship constraint equations during the forming process of flat rectangular tubes:

[0022] This mainly describes the dynamic variation of the aspect ratio of rectangular tubes during hot and cold extrusion forming. The exponential term e... -γt This equation reflects the strain hardening characteristics of materials during extrusion, specifically the characteristic that the deformation rate gradually decreases with increasing extrusion time. The coefficient α characterizes the basic forming properties of the material, typically ranging from 0.8 to 1.2; the coefficient β characterizes the initial deformation, ranging from 0.2 to 0.5; and the coefficient γ characterizes the strain hardening rate, ranging from 0.1 to 0.3. This equation incorporates the time effect during material deformation, making it more consistent with actual engineering conditions compared to traditional static models.

[0023] 2. Constraint equations for the geometric positional relationship between the tie rod system and the crossbeam:

[0024] The relationship between the tie rod placement and the dimensions of the frame members was established. A power function was used to represent the nonlinear influence of different factors, where k1 and k2 represent the influence weights of the height ratio and area ratio, respectively, typically ranging from 0.3 to 0.7. The exponents n1 and n2 reflect the degree of nonlinearity of each factor's influence, ranging from 1.5 to 2.5. This equation comprehensively considers the influence of the geometric characteristics of the frame members on the tie rod placement.

[0025] 3. Constraint equation for stress distribution at tie rod joints:

[0026] This describes the stress concentration effect at the joint of the tie rod. The first term reflects the normal stress concentration, and the second term reflects the tangential stress concentration. The use of square root form reflects the characteristic that stress concentration decreases as the fillet radius increases. This equation simplifies the complex stress state at the joint into an analytical expression that is convenient for engineering applications.

[0027] 4. Constraint equation for stiffness relationship at beam-column connection:

[0028] The relationship between nodal stiffness and member dimensions was established. A power function was used to reflect the nonlinear influence of plate thickness ratio and section height-to-width ratio on nodal stiffness. Coefficients η1 and η2 characterize the influence weight of each factor, ranging from 0.2 to 0.6, while exponents m1 and m2 reflect the degree of nonlinearity, ranging from 1.2 to 2.0.

[0029] Compared with existing technologies, the beneficial effects of the construction method for large-span glass curtain walls using a through-core tie-rod composite frame provided by this invention are:

[0030] 1. The production of right-angled flat-section rectangular tubes using cold extrusion and hot extrusion processes yields excellent dimensional accuracy and mechanical properties, laying a solid foundation for the subsequent fabrication of supporting components. In particular, the hot extrusion process, through localized heating and two-stage rolling, not only eliminates various redundant deformations generated during cold forming but also improves the strength and ductility of the tubes.

[0031] 2. In the design of the through-bolt system, upper and lower washers and tension sleeves were introduced for connection. This not only effectively overcomes the deformation problem during beam installation but also ensures the mechanical coordination between the bolt and the beam, avoiding stress concentration. Furthermore, by establishing a geometric dimension relationship model, the arrangement of the bolts on the beam was optimized, further improving the load-bearing performance of the entire support system.

[0032] 3. During the installation of the long-span frame, the pre-camber of the crossbeams was controlled by adjusting the chain hoist, and a reasonable pre-camber value was determined by simulation analysis. This not only avoided deformation of the crossbeams during hoisting but also ensured the straightness of the overall structure after construction. Meanwhile, during the tensioning of the tie rod system, a specially designed grid-shaped tensioning fixture was used to achieve precise control of the stiffness of the node connections, significantly improving the installation quality.

[0033] In summary, this invention has systematically optimized all aspects from material selection, component manufacturing, support system design to installation and construction, solving the technical problems of traditional construction methods that rely too much on manual experience and lack scientific theoretical guidance and precise control methods. Attached Figure Description

[0034] Figure 1 A flowchart of the method provided by the present invention;

[0035] Figure 2 Detailed construction diagram of the nodes of the through-bolt system;

[0036] Figure 3 Detailed drawing of the column-beam connection node;

[0037] Figure 4 To adjust the layout of the chain hoisting system;

[0038] Figure 5 Detailed drawing of the grid-shaped tensioning fixture;

[0039] Figure 6 Detailed structural drawings of the glass curtain wall decoration system;

[0040] Figure 7 This is a schematic diagram illustrating the construction process of the glass curtain wall in the embodiment.

[0041] Figure 8 This is a schematic diagram of the locking mechanism in the embodiment. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0043] like Figure 1 The diagram shown is a flowchart of a construction method for a large-span glass curtain wall using a through-bracing composite frame provided by this invention. This method includes the following steps:

[0044] S10. Right-angled flat cross-section rectangular tubes are manufactured using cold extrusion and hot extrusion processes. The manufacturing process of right-angled flat cross-section rectangular tubes includes annealing the substrate, cold extruding the annealed substrate to form rounded corner rectangular tubes, and locally heating and hot extruding the rounded corner rectangular tubes to form sharp corners.

[0045] S20. Conduct detailed construction design for the curtain wall through-core tie rod system, decompose the through-core tie rod system into inter-section tie rods, install through-core threaded rods on the horizontal beams, clamp the horizontal beams with upper and lower washers, and connect the inter-section tie rods to the through-core threaded rods through tension sleeves.

[0046] S30. Conduct simulation analysis of the entire construction and installation process of the large-span glass curtain wall system, determine the pre-camber value of the large-span horizontal beam construction, and formulate a horizontal beam construction control table.

[0047] S40. Install the column and fix the column top pin and column body pin, and adjust the verticality and normal angle of the column.

[0048] S50. Large-span crossbeams are hoisted using an adjustable chain hoist. The adjustable chain hoist is set at the 3-point position of the crossbeam, and the horizontal state and pre-camber value of the crossbeam are controlled by adjusting the chain hoist.

[0049] S60. Install the inter-section tie rod, pass the through-bolt through the pre-drilled hole in the crossbeam and lock the crossbeam with the upper and lower washers, and connect the inter-section tie rod to the through-bolt through the tension sleeve;

[0050] S70. Repeat steps S50 to S60 to complete the installation of the single-span beam and tie rod system, install the mid-span hanging column and complete the welding of the beam and column according to the design requirements.

[0051] S80. The tie rod system is tensioned by using a grid-shaped tensioning fixture. The grid-shaped tensioning fixture is fitted onto the upper and lower crossbeams. The fixture is pressed onto the crossbeams by a hydraulic jack and the tensioning sleeve is tightened simultaneously.

[0052] S90. Install glass panels and decorative systems, including installing keel connectors, applying topcoat, and installing glass panels and decorative panels.

[0053] The specific implementation methods of the above steps are described in detail below:

[0054] The specific implementation of step S10 involves producing a right-angled flat-section rectangular tube using cold extrusion and hot extrusion processes. First, the substrate is annealed. The annealing temperature is increased in stages at a rate of 50 degrees Celsius per hour. When the temperature reaches 650 degrees Celsius, it is held for 3 hours, then decreased at a rate of 50 degrees Celsius per hour until the temperature drops to 300 degrees Celsius. This annealing process eliminates work hardening of the substrate, causing crystal rearrangement and improving the metal's ductility. Second, if a round tube is used as the substrate, the annealed substrate is fed into a cold extrusion production line. The roller die parameters are adjusted, and the round tube is cold-extruded into a rounded rectangular tube with a corner radius of 4 to 10 millimeters. The corner radius is selected based on the specifications. During the cold extrusion process, the geometry of the rectangular tube must satisfy the following limiting equation:

[0055]

[0056] Where: h is the height of the rectangular tube, ranging from 80-200mm; b is the width of the rectangular tube, ranging from 40-100mm; t is the extrusion time, generally 3-8s; α is the basic deformation coefficient of the material, generally 1.2-1.5 for steel; β is the strain hardening coefficient of the material, generally 0.3-0.5 for steel; γ is the time decay coefficient, generally 0.4-0.6s⁻¹; ε₁ is the process error term, controlled within ±0.05; this equation describes the dynamic change law of the aspect ratio of the rectangular tube during cold extrusion forming, taking into account the influence of material properties and processing technology. Its main function is to guide the adjustment of extrusion parameters to obtain the ideal cross-sectional shape.

[0057] Then, the rounded rectangular tube is fed into the hot extrusion production line. An induction heating coil is set at the front end of the production line to locally heat the four corners of the rectangular tube. The heating temperature is controlled in the range of 600 to 800 degrees Celsius. The rectangular tube is then fed into the first roller, where a customized roller die is used to extrude the rounded corners of the rectangular tube into sharp corners. After exiting the die, it enters the second roller, where the residual heat is used to perform secondary heat shaping on the formed sharp-cornered rectangular tube to eliminate redundant deformations such as warping, side bending, and twisting. The distance between the two rollers and the extrusion feed speed should ensure that the residual heat temperature of the tube is maintained in the range of 400 to 600 degrees Celsius before the secondary heat shaping. Finally, the finished rectangular tube is end-sawing and grinding to remove burrs, and quality inspection is carried out, including tensile tests, bending tests, and metallographic analysis, to ensure that the geometric dimensions and mechanical properties of the tube meet the design requirements.

[0058] The specific implementation of step S20 involves detailed construction design of the curtain wall tie rod system. First, the tie rods are segmented according to the bay, with each bay having an independent tie rod. The tie rod diameter is determined based on stress calculations, typically within the range of 12 to 20 mm. A through-bolt is installed on the horizontal beam; the minor diameter of the through-bolt thread must not be less than the rod body diameter, and the thread directions at the upper and lower ends must be interchangeable. The through-bolt is clamped to the horizontal beam by upper and lower washers; the washer diameter should be 50 to 80 mm larger than the opening diameter, and the thickness should not be less than 8 mm. A tensioning sleeve is installed at the connection between the tie rod and the through-bolt; the sleeve's internal thread matches the external threads of the tie rod and the through-bolt. A 20 to 30 mm adjustment space must be reserved at the ends of the tie rod and through-bolt sections, taking into account the pre-camber requirements for horizontal beam installation. The geometric positional relationship between the tie rod and the horizontal beam must satisfy the following limiting equation:

[0059]

[0060] in:

[0061] d is the distance from the centerline of the tie rod to the centerline of the crossbeam, generally 100-300mm; L is the span of the crossbeam, determined according to design requirements, generally 6000-12000mm; h1 and h2 are the heights of the upper and lower crossbeams, generally 200-400mm; A1 and A2 are the cross-sectional areas of the upper and lower crossbeams, determined according to the profile; k1 is the height ratio influence coefficient, generally 0.3-0.5; k2 is the area ratio influence coefficient, generally 0.2-0.4; n1 and n2 are geometric nonlinear exponents, generally 1.2-1.5; ε2 is the construction error term, controlled within ±0.02.

[0062] This equation is used to determine the optimal position of the tie rod in the crossbeam, taking into account the influence of the crossbeam's geometry on the tie rod arrangement, which helps optimize the overall stress performance. For the tie rod passing through the crossbeam, a hole is made in the crossbeam body and a pre-welded sleeve is used for reinforcement. The inner diameter of the sleeve should be 6 to 10 mm larger than the tie rod diameter, and the sleeve wall thickness should be no less than 4 mm. The stress distribution at the tie rod joint must satisfy the following limiting equation:

[0063]

[0064] in:

[0065] σ max The maximum stress should not exceed 75% of the material's yield strength; σ n The nominal stress is typically 100-200 MPa; τ m ε is the shear stress, typically 50-100MPa; a is the radius of the node fillet, ranging from 4-8mm; r is the radius of the tie rod, ranging from 6-10mm; ε4 is the stress calculation error term, controlled within ±5MPa.

[0066] This equation is used to evaluate the stress concentration at the tie rod joint, taking into account the stress concentration effect caused by geometric discontinuities, and guiding the detailed design of the joint structure.

[0067] like Figure 2 The diagram shows a detailed construction of the through-bolt system: it illustrates the through-bolt structure at the center of the beam; the arrangement of the upper and lower washers clamping the beam; the connection between the tension sleeve and the through-bolt; and clearly marks the relative positions and connections of each component.

[0068] The specific implementation of step S30 involves simulating and analyzing the entire construction and installation process of the large-span glass curtain wall system. A finite element analysis method is used to establish a finite element model including a solid frame and a tie rod system. First, the deflection values ​​of each large span beam in the completed construction state are calculated. The deflection calculation adopts the large deformation theory considering geometric nonlinearity, taking into account the structural self-weight, tie rod prestress, and loads from the glass panels and external decoration system. The tie rod tension Δl satisfies the following relationship with the applied prestress F, tie rod length L, cross-sectional area A, and elastic modulus E: After calculation and analysis, the deflection values ​​of the major span beams were rounded down and used as the pre-camber values ​​for the construction stage. To verify the rationality of the pre-camber values, a full-process simulation analysis of the curtain wall construction was conducted again. The cambering of the major span beams was achieved by applying simulated negative temperatures to the inter-segment tie rods. The simulated negative temperature Δξ of the inter-segment tie rods was determined using the formula... The calculations yielded Δh, where Δh is the pre-camber value, α is the coefficient of thermal expansion, and L is the length of the tie rod between sections. After confirming through analysis that the straightness of the solid-web frame in the completed construction state meets the design requirements, a construction control table for the crossbeams was developed. The table lists the pre-camber value of each span of the crossbeams and the corresponding control value for the net distance between beams.

[0069] The specific implementation of step S40 involves installing the columns and fixing the pins. First, the column installation position is determined based on surveying and layout, and then verified using a theodolite. After the column is hoisted into place, the top and body pins are fixed, and the column's verticality is adjusted, with an allowable deviation of 3 mm per meter. The normal angle of the column is adjusted to ensure it is perpendicular to the curtain wall surface, with an allowable angle deviation of 0.1 degrees. After the column is adjusted to the correct position, the column base insert is welded to the foundation's embedded plate. The weld is continuous, with a weld height of not less than 6 mm. Throughout the entire construction process, the column base and insert are not welded together to meet design requirements. Figure 3 The diagram shows a detailed view of the column-beam connection node: it illustrates the vertical connection structure between the column and the beam; it indicates the installation positions of the column top pin and the column body pin; it shows the welding connection method between the beam and the column; and it indicates the positional relationship of the main components.

[0070] The specific implementation of step S50 involves using adjustable chain hoists to lift the large-span crossbeam. First, an adjustable chain hoist is installed at each of the three points on the upper crossbeam, with a rated lifting capacity of not less than 2 tons. The crossbeam is lifted using a double-point lifting method, with the lifting point spacing being 60% to 70% of the crossbeam length. After the crossbeam is in place, the chain hoists are used to hook the crossbeam, and the chain hoists are adjusted to keep the crossbeam horizontal, with an allowable deviation of 2 mm per meter. The crossbeam is then horizontally inserted into the end inserts to a depth of not less than 50 mm, and the pre-opened window plates are completed and welded. After the crossbeam is installed, with the assistance of a crane, both adjustable chain hoists are simultaneously tightened, causing the large-span crossbeam to arch upwards. The clear distance between the beams is measured using a level or total station, and the chain hoists are adjusted according to the measurement results until the clear distance between the beams meets the requirements of the construction control table, where the allowable deviation of the clear distance between the beams is ±2 mm. Figure 4 The diagram shown is for adjusting the chain hoisting system layout: it illustrates the chain hoist arrangement at the three points of the crossbeam; it indicates the required ratio of the hoisting point spacing; it shows the connection method between the chain hoist and the crossbeam; and it marks the key positions for levelness control.

[0071] The specific implementation of step S60 involves installing the inter-section tie rods. First, the inter-section tie rods are numbered and checked to ensure that the numbers and lengths are correct before installation. The through-bolt is passed through the pre-drilled hole in the crossbeam, ensuring that the deviation between the bolt axis and the hole axis does not exceed 2 mm. The crossbeam is then locked in place using upper and lower washers, ensuring a tight fit between the washers and the crossbeam surface. If necessary, anti-rust paint can be applied to the contact surfaces. The inter-section tie rods are then connected to the through-bolt using a tensioning sleeve. During connection, it is essential to ensure that the tie rod axis and the through-bolt axis are collinear, with an allowable deviation of 0.1 degrees between the two axes. Furthermore, the screw-in depth at both ends of the tensioning sleeve should be approximately consistent.

[0072] The specific implementation of step S70 involves repeating steps S50 to S60 to complete the installation of the single-span beam and tie rod system. The specific construction sequence is to install the beams one by one from top to bottom, installing the tie rod for each beam section after installation. After the single-span beam and tie rod system is installed, the mid-span hanging column is installed, with an allowable vertical deviation of 2 mm per meter. The beams and columns are welded according to design requirements, using continuous welding with a weld height of not less than 6 mm. Symmetrical welding is employed to prevent welding deformation.

[0073] The specific implementation of step S80 involves using a grid-shaped tensioning fixture to tension the tie rod system. First, a grid-shaped tensioning fixture is fabricated, welded from channel steel and angle steel. The longitudinal and transverse beams of the fixture are made of No. 16 channel steel, and the stiffening ribs are made of 6mm thick angle steel. The tensioning fixture is fitted onto the upper and lower transverse beams of the designated tensioning zone, with the deviation of the fixture's center position from the tie rod center not exceeding 200mm. Hydraulic jacks are installed on the upper transverse beam, with a 16mm thick steel plate underneath. Two jacks are manually operated to simultaneously press against the upper transverse beam of the fixture, and the tensioning sleeve is tightened synchronously. The tension force is controlled by the hydraulic gauge reading, tensioning to 105% of the design tension force. After maintaining this for 10 minutes, the pressure is released to 100% of the design tension force. The hydraulic jack pressure gauge is observed; after confirming no pressure loss, the tensioning fixture is removed, and tensioning proceeds to the other half of the span. The stiffness relationship at the transverse beam-column connection must satisfy the following limiting equation:

[0074]

[0075] Where: K is the actual stiffness of the node, in N·m / rad; K0 is the reference stiffness, generally taken as 2×10⁵ N·m / rad; t is the thickness of the connecting plate, ranging from 8 to 12 mm; d is the pin diameter, ranging from 20 to 30 mm; h is the beam height, ranging from 200 to 400 mm; b is the beam width, ranging from 100 to 200 mm; η1 is the thickness influence coefficient, ranging from 0.2 to 0.4; η2 is the section influence coefficient, ranging from 0.3 to 0.5; m1 and m2 are geometric nonlinear exponents, ranging from 1.2 to 1.5; ε5 is the stiffness error term, controlled within ±1000 N·m / rad. This equation is used to evaluate the stiffness characteristics of the node connection, considering the influence of the geometric dimensions of the connecting components on the node stiffness, and guiding the structural design of the connection node. Figure 5 The image shows a detailed drawing of the grid-shaped tensioning fixture: it illustrates the overall grid structure of the fixture; it shows the installation position of the hydraulic jacks; it marks the relative positions of the upper and lower crossbeams; and it demonstrates the connection between the fixture and the structure.

[0076] The specific implementation of step S90 involves installing the glass panels and decorative system. First, during the construction of the supporting system, the decorative system keel connectors are installed and welded in place. Spot welding is used, with each connector having no fewer than four weld points, and each weld point having an area of ​​no less than 50 square millimeters. After grinding the weld seams of the composite frame, intermediate paint and fluorocarbon topcoat are applied. Before painting, the weld seams are derusted to a rust removal grade no lower than Sa2.5. The glass panel system installation proceeds in the following order: aluminum alloy base installation, glass panel installation, panel joint adjustment and vertical joint fixing, horizontal and vertical joint caulking, aluminum alloy pressure plate installation and caulking, and aluminum alloy buckle installation and caulking. The panel joint width is controlled within the range of 12 to 15 millimeters. When installing a decorative panel system on a large-span glass curtain wall, after the glass panels are installed, a fire-retardant coating must be fully applied to the outer layer of the glass panels, with a coating thickness of no less than 0.3 millimeters, before proceeding with the decorative system keel construction. After the decorative panels are installed, a special cleaning agent is used to clean the fire-retardant coating from the glass panels. Figure 6 The diagram shows a detailed construction of a glass curtain wall decoration system: it illustrates the installation structure of the glass panels; the arrangement of the keel connectors; the required panel joint width; and the installation location of the decorative panels.

[0077] Specifically, the principle of this invention is:

[0078] Firstly, in the material selection and component manufacturing stages, right-angled flat-section rectangular tubes are produced using cold extrusion and hot extrusion processes. This process effectively controls the geometric dimensions of the tubes, avoiding the severe deformation problems that occur during the cold extrusion of traditional round tubes. Furthermore, local heating and secondary hot forming significantly improve the strength and ductility of the tubes. In the design, a model relating the tube geometry to the processing parameters is established, providing a basis for adjusting extrusion parameters to obtain the ideal cross-sectional shape. These high-performance rectangular tubes, serving as the main load-bearing components of the composite frame, lay a solid foundation for the subsequent design and installation of the support system.

[0079] Secondly, in the design of the through-bolt system, this invention employs a connection method combining upper and lower washers and tension sleeves. The upper and lower washers effectively prevent deformation of the crossbeam during installation, while the tension sleeve provides an adjustable joint between the rod and the crossbeam, ensuring their mechanical compatibility. Simultaneously, by establishing a model relating the rod position to the crossbeam's geometry, the rod's arrangement is optimized, resulting in a more rational stress distribution throughout the support system. This through-bolt system design not only improves the overall structural stability but also creates favorable conditions for subsequent construction and installation.

[0080] Furthermore, in the installation and construction of the long-span frame, this invention uses an adjustable chain hoist to control the pre-camber of the crossbeams, and combines simulation analysis to determine a reasonable pre-camber value. This approach not only effectively avoids deformation of the crossbeams during hoisting, but also ensures that the straightness of the overall structure meets design requirements after construction through precise control of the pre-camber value. Simultaneously, in the tensioning construction of the tie rod system, a specially designed grid-shaped tensioning fixture is used to achieve precise control of the stiffness of the node connections, ensuring the installation quality of the tie rod system.

[0081] To better understand and implement this invention, a specific application scenario is provided below: A commercial complex project in a certain city is implementing the large-span glass curtain wall construction method of the through-core tie-rod composite frame proposed in this invention. The total construction area of ​​the project is approximately 80,000 square meters, of which glass curtain walls account for more than 60%, with an average single span of 10 meters. To ensure the overall construction quality of the large-span glass curtain wall, the owner and the general contractor jointly decided to adopt the construction method of this invention. Figure 7 As shown, the specific construction principle is as follows: the composite frame tie rod system is decomposed into each segment, and the large-span beams are installed alternately with the tie rod system from top to bottom. For each beam installed, the chain hoist is adjusted to the predetermined shape, then the corresponding tie rod is installed in place and the beam is locked, fixing its shape. The process is then repeated for the next beam, ensuring the structural configuration remains under control. For example, Figure 8As shown, to achieve the alternating installation and locking mechanism of the large-span beams and tie rod system, adaptive construction detailing of the curtain wall structure system is required to ensure a balance between reliability, ease of alternating installation, and aesthetics. Through this process, all large-span beams can be installed without additional temporary supports. After the composite frame components are installed, the tie rod system can be tensioned directly, eliminating the cumbersome processes of temporary support installation, unloading, and post-processing. This significantly reduces construction costs while shortening the construction cycle and improving efficiency. The specific construction process is described below:

[0082] I. Material Selection and Component Fabrication

[0083] First, based on the stress analysis of the curtain wall support system, Q345B steel was selected as the main base material, with a yield strength of not less than 345 MPa. To ensure the production of right-angled rectangular tubes with excellent geometric accuracy and mechanical properties, the following manufacturing process was established:

[0084] 1. Substrate Pretreatment. The Q345B steel plate undergoes annealing treatment, specifically as follows: the temperature is raised to 650 degrees Celsius at a rate of 50 degrees Celsius per hour, held at that temperature for 3 hours, and then cooled to 300 degrees Celsius at a rate of 50 degrees Celsius per hour. This annealing process effectively eliminates work hardening of the substrate and improves the ductility of the metal.

[0085] 2. Cold extrusion forming. The annealed steel sheet is fed into the cold extrusion production line. By adjusting the roller die parameters, the base material is extruded into a rounded rectangular tube with a corner radius of 6 mm using a cold extrusion method. During the cold extrusion process, the aspect ratio of the tube meets the following relationship:

[0086]

[0087] Where h is the height of the rectangular tube, taken as 160 mm; b is the width of the rectangular tube, taken as 80 mm; and t is the extrusion time, taken as 5 seconds. This equation describes the dynamic change of the tube's height-to-width ratio during the extrusion process, providing a basis for adjusting the extrusion parameters.

[0088] 3. Hot Extrusion Forming. The cold-extruded rounded rectangular tube is fed into the hot extrusion production line. Induction heating coils are installed at the front end of the production line to locally heat the four corners of the tube, controlling the heating temperature at approximately 700 degrees Celsius. The tube is then fed into the first roller, where a customized die extrudes the rounded corners into sharp corners. After exiting the die, it enters the second roller for secondary hot forming to eliminate any unnecessary deformation such as warping or lateral bending that may have occurred during the hot forming process. The spacing between the two rollers and the extrusion feed speed should ensure that the residual heat temperature of the tube is maintained between 450 and 550 degrees Celsius before the secondary hot forming.

[0089] Finally, the finished rectangular tubes undergo end sawing, grinding, and other processing, and are tested for tensile strength and bending strength to ensure that the geometric dimensions and mechanical properties of the tubes meet the design requirements. Table 1 lists the main technical parameters of the rectangular tubes.

[0090] Table 1 Main Technical Parameters of Rectangular Tubes

[0091] Technical parameters numerical values Cross-sectional dimensions (mm) 160×80 <![CDATA[Cross-sectional area (mm 2 )]]> 10800 Bending strength (MPa) 620 Tensile strength (MPa) 580 Elongation (%) 22

[0092] II. Support System Design

[0093] 1. Through-bolt system design. Based on the overall stress analysis of the curtain wall, Φ16 mm high-strength steel tie rods were selected as the inter-section reinforcement. Φ24 mm through-bolts were installed on the crossbeams, and the through-bolts were reliably locked to the crossbeams using upper and lower Φ80 mm × 8 mm washers. A Φ28 mm tensioning sleeve was used to connect the tie rods and through-bolts. The internal thread of the sleeve matched the external threads of the tie rods and through-bolts, and a 25 mm adjustment space was provided at the ends of both the tie rods and through-bolts.

[0094] The optimal position of the tie rod in the beam is determined by the following relationship:

[0095]

[0096] Where d is the distance from the center line of the tie rod to the center line of the crossbeam, which is 220 mm; L is the span of the crossbeam, which is 10000 mm; h1 and h2 are the heights of the upper and lower crossbeams, respectively, both of which are 320 mm; A1 and A2 are the cross-sectional areas of the upper and lower crossbeams, which are calculated to be 12800 square millimeters and 13600 square millimeters, respectively.

[0097] For the tie rod passing through the crossbeam, a Φ22 mm pre-embedded sleeve with a 4 mm wall thickness is installed in the crossbeam body. The maximum stress at the tie rod joint must meet the following requirements:

[0098]

[0099] Where, σ max The maximum stress at the node shall not exceed 75% of the yield strength of the steel; a is the radius of the node fillet, which is 6 mm; r is the radius of the tie rod, which is 8 mm.

[0100] 2. Installation Design of Large-Span Beams. Based on the finite element simulation analysis of the overall curtain wall construction process, the pre-camber values ​​of the large-span beams are calculated as shown in Table 2.

[0101] Table 2 Pre-camber values ​​for large-span crossbeams

[0102] Cross-number Pre-camber value (mm) 1 30 2 28 3 32 4 27 5 31

[0103] To verify the rationality of the pre-camber value, a simulation of the overall curtain wall construction process was conducted. This simulation employed a method of applying simulated negative temperatures to the inter-segment tie rods to model the cambering behavior of the large-span beams. Based on calculations, the simulated negative temperatures for each inter-segment tie rod are as follows:

[0104]

[0105] Where Δh is the pre-camber value, taken from Table 2; α is the linear expansion coefficient of steel, taken as 11.8×10^(-6) / ℃; L is the length of the inter-section tie rod, approximately 1000 mm.

[0106] Further analysis confirmed that the straightness of the solid-web frame met the design requirements after construction was completed. Based on this, a construction control table for the crossbeams was developed, specifying the pre-camber value for each span of the crossbeams and the corresponding control value for the net distance between beams.

[0107] III. Installation and Construction of Large-Span Frames

[0108] 1. Column Installation. Based on the survey lines, determine the installation positions of the columns and verify them using a theodolite. After the columns are hoisted into place, first fix the top and body pins, and adjust the verticality of the columns, with an allowable deviation of no more than 3 mm / m. Simultaneously, adjust the normal angle of the columns to ensure they are perpendicular to the curtain wall surface, with an allowable angle deviation of no more than 0.1 degrees. After the columns are adjusted to the correct position, weld the column base insert to the foundation embedded parts, using continuous welding with a weld height of no less than 6 mm.

[0109] 2. Erection of large-span crossbeams. At each of the three-quarter points of the upper crossbeam, install an adjusting chain hoist with a rated lifting capacity of not less than 2 tons. The crossbeams are hoisted using a double-point method, with the hoisting point spacing being 65% of the crossbeam length. After the crossbeams are in place, hook the crossbeams with the adjusting chain hoists and adjust them to keep the crossbeams horizontal, with a permissible deviation of no more than 2 mm / m. Insert the crossbeam horizontally into the end inserts to a depth of not less than 50 mm, and weld the pre-reserved window plates.

[0110] With the assistance of the crane, two adjusting chain hoists are simultaneously tightened, causing the crossbeam to arch upwards. A total station is used to measure the net distance between the beams in real time, and the chain hoists are adjusted as needed based on the measurement results until the net distance between the beams meets the requirements of the construction control table, where the allowable deviation for the net distance between the beams is ±2 mm.

[0111] 3. Installation of Inter-section Tie Rods. First, verify the numbering and length of the inter-section tie rods. After confirming that the numbers and lengths are correct, proceed with the installation. Pass the through-bolt through the pre-drilled Φ22 mm hole in the crossbeam, ensuring that the deviation between the bolt axis and the hole axis does not exceed 2 mm. Secure the through-bolt to the crossbeam reliably using upper and lower Φ80 mm × 8 mm washers, ensuring a tight fit between the washers and the crossbeam surface.

[0112] Use a Φ28 mm tensioning sleeve to connect the inter-section tie rod to the through-bolt. During connection, ensure that the axis of the tie rod and the axis of the through-bolt are collinear, with an allowable deviation of no more than 0.1 degrees between the two axes, and ensure that the screw-in depth at both ends of the tensioning sleeve is basically the same.

[0113] 4. Tensioning of the tie rod system. A grid-shaped tensioning fixture was fabricated. Both the longitudinal and transverse beams of the fixture were made of No. 16 channel steel, and the stiffening ribs were made of 6mm thick angle steel. The fixture was fitted onto the upper and lower transverse beams of the designated tensioning area, with the center of the fixture no more than 200mm from the center of the tie rod. Hydraulic jacks were installed on the upper transverse beam, with 16mm thick steel plates placed under the jacks.

[0114] Two hydraulic jacks are operated manually to simultaneously press down on the crossbeam of the fixture while the tensioning sleeve is tightened. The tension is controlled by a hydraulic gauge. First, the force is increased to 105% of the design tension, maintained for 10 minutes, and then reduced to 100% of the design value. After observing the hydraulic gauge and confirming that there is no pressure loss, the tensioning fixture can be removed, and the process can begin for the next half-span.

[0115] The connection stiffness of the beam-column joint should meet the following requirements:

[0116]

[0117] Where K is the actual stiffness of the node, approximately 2.4 × 10⁻⁶. 5 Newton-meters per radian; t is the thickness of the connecting plate, taken as 10 mm; d is the diameter of the pin, taken as 25 mm; h is the height of the crossbeam, taken as 320 mm; b is the width of the crossbeam, taken as 160 mm.

[0118] 5. Glass Curtain Wall System Installation. The installation of the glass curtain wall system will proceed concurrently with the construction of the support system. First, the keel connectors of the decorative system will be welded into place during the support system construction process, with each connector having at least four Ф6 mm spot welds.

[0119] After the composite frame welds are ground, intermediate paint and fluorocarbon topcoat are applied. Before painting, the welds are treated with Sa2.5 grade rust removal. The installation of the glass panel system is strictly carried out in the following order: aluminum alloy base -> glass panel -> panel gap adjustment and vertical joint fixing -> horizontal and vertical joint caulking -> aluminum alloy pressure plate installation and caulking -> aluminum alloy buckle installation and caulking. The panel gap width is controlled at 12-15 mm.

[0120] For external decorative panel systems in large-span glass curtain walls, after the glass panels are installed, a 0.3 mm thick fire-retardant coating is first applied to the outer layer of the glass before installing the decorative keel. After all the decorative panels are installed, the fire-retardant coating on the glass surface is cleaned using a special cleaning agent.

[0121] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A construction method for a large-span glass curtain wall with a through-core tie-rod composite frame, characterized in that, Includes the following steps: S10. A right-angled flat-section rectangular tube is manufactured using cold extrusion and hot extrusion processes. The manufacturing process includes annealing the substrate, cold extruding the annealed substrate to form a rounded-corner rectangular tube, and locally heating and hot extruding the rounded-corner rectangular tube to form sharp corners. During the cold and hot extrusion forming process, the aspect ratio of the rectangular tube satisfies the following: ,in, The height of the rectangular tube. The width of the rectangular tube. To compress time, The basic deformation coefficient of the material. The strain hardening coefficient of the material. The time decay coefficient, This is a process error item; S20. Conduct detailed construction design for the curtain wall through-core tie rod system, decompose the through-core tie rod system into inter-segment tie rods, install through-core threaded rods on the horizontal beams, clamp the horizontal beams with upper and lower washers, and connect the inter-segment tie rods to the through-core threaded rods through tension sleeves; S30. Simulate and analyze the entire construction and installation process of the large-span glass curtain wall system, determine the pre-camber value of the large-span horizontal beam construction, and formulate a horizontal beam construction control table. S40. Install the column and fix the column top pin and column body pin, and adjust the verticality and normal angle of the column. S50. Large-span crossbeams are hoisted using an adjustable chain hoist. The adjustable chain hoist is set at the 3-point position of the crossbeam and the horizontal state and pre-camber value of the crossbeam are controlled by the adjustable chain hoist. S60. Install the inter-section tie rod, pass the through-hole screw through the pre-drilled hole of the crossbeam and lock the crossbeam with the upper and lower washers, and connect the inter-section tie rod to the through-hole screw through the tension sleeve; S70. Repeat steps S50 to S60 to complete the installation of the single-span beam and tie rod system, install the mid-span hanging column and complete the welding of the beam and column according to the design requirements. S80. The tie rod system is tensioned using a grid-shaped tensioning fixture. The grid-shaped tensioning fixture is fitted onto the upper and lower crossbeams. The fixture is pressed onto the crossbeams by a hydraulic jack and the tensioning sleeve is tightened simultaneously. S90. Install glass panels and decorative systems, including installing keel connectors, applying topcoat, and installing glass panels and decorative panels.

2. The construction method for a large-span glass curtain wall with a through-core tie-rod composite frame according to claim 1, characterized in that, Step S10 specifically includes: first, annealing the substrate using a segmented heating method, raising the temperature to 650 degrees Celsius at a rate of 50 degrees Celsius per hour and holding it for 3 hours, then cooling it down to 300 degrees Celsius at a rate of 50 degrees Celsius per hour; second, feeding the annealed substrate into a cold extrusion production line, adjusting the roller die parameters to extrude the substrate round tube into a rounded rectangular tube with a corner radius of 4 to 10 mm, the rounded rectangular tube having a height of 80 to 200 mm and a width of 40 to 100 mm; then... The rounded rectangular tube is fed into the hot extrusion production line. An induction heating coil is set at the front end of the production line to locally heat the four corners of the rounded rectangular tube to 600 to 800 degrees Celsius. Then, the rounded rectangular tube is fed into the first roller to extrude the rounded corners into sharp corners. After the sharp-cornered rectangular tube exits the die, it enters the second roller for secondary hot forming at a temperature of 400 to 600 degrees Celsius. Finally, the sharp-cornered rectangular tube is end-sawing and polishing, and tensile tests, bending tests, and metallographic analysis are performed.

3. The construction method for a large-span glass curtain wall with a through-core tie-rod composite frame according to claim 1, characterized in that, Step S20 specifically includes: firstly, dividing the through-bolt into sections according to the inter-sections, with each section having an independent rod section, the diameter of which is 12 to 20 mm; the through-bolt clamping the crossbeam with upper and lower washers, the washers having a diameter 50 to 80 mm larger than the opening diameter and a thickness of not less than 8 mm; a tensioning sleeve being installed at the connection between the rod and the through-bolt, the internal thread of which matches the external thread of the rod and the through-bolt, with a 20 to 30 mm adjustment space reserved at the ends of the rod and the through-bolt sections; the distance from the centerline of the rod to the centerline of the crossbeam being 100 to 300 mm; the span of the crossbeam being 6000 to 12000 mm, and the height of the upper and lower crossbeams being 200 to 400 mm; the crossbeam body having an opening and a pre-welded sleeve for reinforcement, the inner diameter of which is 6 to 10 mm larger than the diameter of the rod, and the sleeve wall thickness being not less than 4 mm.

4. The construction method for a large-span glass curtain wall with a through-core tie-rod composite frame according to claim 1, characterized in that, Step S30 specifically includes: establishing a finite element model containing a solid web frame and tie rod system using the finite element analysis method; calculating the deflection values ​​of major span beams under the completed construction state; the deflection calculation adopts the theory of geometric nonlinear large deformation, taking into account the structural self-weight, tie rod prestress, glass panel and external decoration system loads; rounding the deflection values ​​of major span beams as the pre-camber values ​​for the construction stage; conducting a full-process simulation analysis of the curtain wall construction, wherein the camber of the major span beams is carried out by applying simulated negative temperature to the inter-span tie rods; and after confirming through analysis that the straightness of the solid web frame under the completed construction state meets the design requirements, formulating a beam construction control table.

5. The construction method for a large-span glass curtain wall with a through-core tie-rod composite frame according to claim 1, characterized in that, Step S40 specifically includes: determining the column installation position based on the survey and setting out, and verifying it using a theodolite; after the column is hoisted into place, fixing the column top pin and column body pin, and adjusting the verticality of the column, wherein the allowable deviation of the verticality is 3 mm per meter; adjusting the normal angle of the column to ensure that the column is perpendicular to the curtain wall surface, wherein the allowable deviation of the angle is 0.1 degrees; welding and fixing the column base insert to the foundation pre-embedded plate, wherein the weld is continuous and the weld height is not less than 6 mm; the column base and the insert are not welded during the entire construction process.

6. The construction method for a large-span glass curtain wall with a through-core tie-rod composite frame according to claim 1, characterized in that, Step S50 specifically includes: setting an adjusting chain hoist at each of the three points on the upper crossbeam, the rated lifting capacity of the adjusting chain hoist being no less than 2 tons; hoisting the crossbeam using a double-point lifting method, with the distance between the lifting points being 60 to 70 mm of the crossbeam length; after the crossbeam is in place, using the adjusting chain hoist to hook the crossbeam and adjusting it to keep the crossbeam horizontal, the allowable deviation of the horizontality being 2 mm per meter; horizontally inserting the crossbeam into the end insert, the insertion depth being no less than 50 mm, and welding the pre-opened window plate to complete the gap; simultaneously tightening the two adjusting chain hoists with the help of a crane to drive the large-span crossbeam upward arching, using a level or total station to measure the net distance between the beams, and adjusting the adjusting chain hoists according to the measurement results until the net distance between the beams meets the requirements of the construction control table, the allowable deviation of the net distance between the beams being ±2 mm.

7. The construction method for a large-span glass curtain wall with a through-core tie-rod composite frame according to claim 1, characterized in that, Step S60 specifically includes: verifying and confirming the number and length of the inter-section tie rods; passing the through-bolt through the pre-drilled hole in the crossbeam, with the deviation between the axis of the through-bolt and the axis of the pre-drilled hole not exceeding 2 mm; locking the crossbeam with upper and lower washers, with the washers tightly fitting against the surface of the crossbeam; connecting the inter-section tie rods and the through-bolt using a tensioning sleeve, ensuring that the axis of the inter-section tie rods and the axis of the through-bolt are collinear, with an allowable deviation of 0.1 degrees between the two axes, and ensuring that the screw-in depth of both ends of the tensioning sleeve is basically the same.

8. The construction method for a large-span glass curtain wall with a through-core tie-rod composite frame according to claim 1, characterized in that, Step S70 specifically includes: installing the crossbeams one by one from top to bottom, and installing the tie rod for each crossbeam; after the single-span crossbeam and tie rod system are installed, installing the mid-span hanging column, the allowable deviation of the verticality of the hanging column is 2 mm per meter; completing the welding of the crossbeam and the column according to the design requirements, the weld is continuous and the weld height is not less than 6 mm, and the welding is done in a symmetrical manner.

9. The construction method for a large-span glass curtain wall with a through-core tie-rod composite frame according to claim 1, characterized in that, Step S80 specifically includes: fabricating a grid-shaped tensioning fixture, which is welded from channel steel and angle steel, wherein the longitudinal and transverse beams of the fixture are all made of No. 16 channel steel, and the stiffening ribs are made of 6 mm thick angle steel; fitting the grid-shaped tensioning fixture onto the upper and lower transverse beams of the designated tensioning zone, with the center position of the grid-shaped tensioning fixture deviating from the center of the tie rod by no more than 200 mm; installing hydraulic jacks on the upper transverse beam, with a 16 mm thick steel plate underneath the hydraulic jacks; manually operating two hydraulic jacks to simultaneously press the upper transverse beam of the fixture and simultaneously tighten the tensioning sleeve; tensioning to the design tension force of 105 and holding for 10 minutes, then releasing the pressure to 100 of the design tension force; observing the pressure of the hydraulic jacks to confirm that there is no pressure loss, and then removing the grid-shaped tensioning fixture.

10. The construction method for a large-span glass curtain wall with a through-core tie-rod composite frame according to claim 1, characterized in that, Step S90 specifically includes: installing and welding the decorative system keel connectors into place during the construction of the support system. The connectors are welded using spot welding, with each connector having no fewer than four weld points and each weld point having an area of ​​no less than 50 square millimeters. After grinding the weld seams of the composite frame, apply intermediate paint and fluorocarbon topcoat. Before painting, the weld seams are derusted to a rust removal grade of no less than Sa2.

5. The installation is carried out in the following order: aluminum alloy base installation, glass panel installation, panel seam adjustment and vertical seam fixing, horizontal and vertical seam caulking, aluminum alloy pressure plate installation and caulking, and aluminum alloy buckle installation and caulking. The panel seam width is controlled within the range of 12 to 15 millimeters. The outer layer of the glass panel is fully coated with fire-retardant paint, with a coating thickness of no less than 0.3 millimeters. Then, the decorative system keel construction is carried out. After the decorative panels are installed, the fire-retardant paint on the glass panels is cleaned with a special cleaning agent.

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