A high-altitude overhanging non-supported steel-concrete composite structure system based on numerical simulation and a construction method thereof

Abstract

The application discloses a high-altitude overhanging non-supporting steel-concrete composite structure system based on numerical simulation and a construction method thereof, which comprises an overhanging inner platform and an overhanging outer platform connected to a non-overhanging area frame system in a concave shape, wherein the non-overhanging area frame system comprises a structure column KZ1 at the junction of a non-overhanging area and an overhanging platform, a concrete frame beam KL2, a concrete frame beam KL3 and an L1 beam; reliable supports are arranged under the overhanging inner platform; sectional combined floors are poured in sequence from the non-overhanging area to the overhanging outer platform; steel beam embedded parts are fixedly arranged on the non-overhanging area frame system; the steel beam embedded parts are fixed with steel beams; the steel beams comprise a steel beam one GL1, a steel beam two GL2 and a steel beam three GL3; and the application further comprises finite element software. The application satisfies the non-supporting construction of the high-altitude overhanging structure, has the advantages of safety and reliability and strong operability, and has the advantages of convenient construction, high economic efficiency and the like, as compared with temporary support erection in the high-altitude overhanging area.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a high-altitude cantilevered unsupported steel-concrete composite structure system based on numerical simulation and its construction method. Background Technology

[0002] With the development of building technology, the design and structural forms of high-rise buildings have become more diversified, and the facade shapes have become more complex. This has led to an increasing number of cantilever structures in high-rise buildings. These novel architectural shapes give people a visual impact and expand the usable space, but at the same time, they create many challenges for building structure construction.

[0003] The conventional practice for cantilevered structures around the core tube of high-rise concrete frames is to erect a corresponding temporary triangular support system or steel platform support system under the cantilever structure. The erection of temporary support systems is often difficult, and different structural forms require different support systems, which requires a lot of construction costs. At the same time, the safety of erecting temporary support systems at high altitudes is difficult to guarantee.

[0004] Therefore, there is an urgent need for a high-altitude cantilever unsupported steel-concrete composite structure system and its construction method based on numerical simulation, which can effectively solve the difficulties in the construction process of this type of cantilever structure, is highly operable, convenient to construct, and can safely, economically and efficiently meet the construction requirements of high-altitude cantilever structures. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a numerically simulated high-altitude cantilevered unsupported steel-concrete composite structure system. This system includes an inner cantilevered platform and an outer cantilevered platform connected to a concave, non-cantilevered frame system. The inner and outer cantilevered platforms are separated by a concrete frame beam KL1. The non-cantilevered frame system includes structural columns KZ1, concrete frame beams KL2, KL3, and L1 beams at the junction of the non-cantilevered area and the cantilevered platform. Reliable supports are erected beneath the inner cantilevered platform to facilitate hoisting, welding, rebar tying, and pre-embedded construction. The platform consists of a non-cantilevered area and an outer cantilevered platform, where composite floor slabs are poured in segments. Steel beam embedded parts are fixedly installed on the frame system of the non-cantilevered area, and these embedded parts are fixed to the steel beams. The steel beams include steel beam GL1, steel beam GL2, and steel beam GL3. Steel beam GL1 and steel beam GL2 form a robust integral structure with the concrete in the non-cantilevered area, while steel beam GL3 connects the cantilevered area to the structure as a whole. The system also includes finite element software for pre-simulating and analyzing the deformation and strain of the composite structural system. The finite element software includes strain gauges installed on the steel beams.

[0006] Preferably, the composite floor slab is constructed by using profiled steel sheets and concrete working together.

[0007] Preferably, the steel beam is made of H-beams.

[0008] One construction method, the steps are as follows:

[0009] S1: Construction preparation, component segmentation and numbering: Check the material component usage according to the design drawings, verify the specifications, models, materials, etc. of the components, prepare a complete construction plan and technical briefing, and number the embedded parts and components in non-cantilever and cantilever areas according to the steel structure detailed construction drawings.

[0010] S2: Erection of formwork system for non-cantilevered areas and cantilevered platforms: The formwork system for non-cantilevered areas is erected according to the following method: the horizontal bar spacing of the middle layer is 1500mm, the horizontal bar spacing of the top layer is 1000mm, the horizontal and vertical span is 1200mm, and the formwork system for non-cantilevered areas is constructed using pads, disc-type formwork support frames, and U-shaped support top bracing. The main keel is made of 100×50×2.5 square steel pipe. When erecting the formwork system for non-cantilevered areas, the two extended spans serve as external scaffolding protection for the non-cantilevered areas.

[0011] S3: Installation and Pouring of Embedded Parts in Non-Cantilever Areas: At the junction of the non-cantilever area and the cantilever platform, according to the design drawings, embedded parts for the hinged joint between GL1 and the concrete beam, as well as embedded parts for the composite floor slab support angle steel, are installed on the sides of beams KL1, L1, and KL3. On the structural column KZ1 at the junction of the non-cantilever area and the cantilever platform, and on the side of beam L1, the main reinforcement bars of the cantilever platform frame beam KL1 and beam L2 are pre-inserted. After the reinforcement bars are tied, concrete is poured in the non-cantilever area. KL2, KL3, and L1 are poured first after the reinforcement bars are tied and the embedded parts are installed. After the reinforcement bars of beams KL1 and L2 are tied and the embedded parts are installed, GL1 is hoisted through KL1 before pouring.

[0012] S4: Hoisting of steel beams GL1 and GL2 on the cantilever platform: After the non-cantilever area structure has reached its design strength, it will be dismantled. A third lifting lug will be installed on steel beam GL1, approximately 1m from the end of the beam. Simultaneously, the bottom support of beam KL1 is already in place. All beams are supported by 60cm vertical supports on both sides, and the support frame directly below the beam is longitudinally and laterally aligned. Safety measures are in place, and the hoisting equipment meets requirements. → The steel beam is hoisted to the installation height. → It is moved and inserted into the concrete on the operating platform. From the middle of the upper and lower main reinforcement bars of concrete KL1, until the interference between the reinforcement frame and the sling, use a hoist chain to tie the end of the steel beam and make temporary fixation. Then loosen one end of the hook and fix it to the position of the third lifting lug. After reinstalling the hoisting measures, continue to move the steel beam. At this time, the hoist chain can be loosened. The hook can only be loosened after the high-strength bolts at the end of the steel beam are completely fixed. After GL1 is installed, install GL2. Install the remaining three GL1 bars in the same way. After all GL1 bars are installed, seal the side formwork of KL1 and pour concrete.

[0013] S5: Set up strain gauges based on the analysis results of finite element software: Use the finite element software ANSYS to model and load calculations for different working conditions, simulate the stress and end displacement of the cantilever structure under different conditions throughout the construction stage, and establish a finite element model based on the design drawings and actual site conditions.

[0014] S6: Formwork support for cantilever inner platform beams KL1 and L2: After the steel beams are hoisted, erect the cantilever inner platform structural beam scaffolding and support the concrete structural beam formwork.

[0015] S7: Reinforcement binding and pouring of cantilever inner platform beams KL1 and L2: First, bind the reinforcement of the concrete structural beam KL1, which intersects with the steel beam GL1. The main reinforcement of the beam is mechanically connected to the dowel bars on both sides through reinforcement sleeves. The web reinforcement of the main beam is passed through the Φ24 holes reserved in the web of the steel beam. Studs are welded to the top of the steel beam to support the upper reinforcement of the beam, and 4 rows are added at the bottom of the steel beam. Additional reinforcement of 14, the bottom and 150mm sides of the steel beam are the stirrup reinforcement zone, with a spacing of 50mm;

[0016] S8: Installation of steel beam GL3 and laying of steel truss floor deck for cantilever platform: Connect the secondary longitudinal steel beam GL3 to the extended connecting plate of the main beam GL1 steel beam. Use 3 M20 high-strength bolts to firmly connect the secondary steel beam to the extended connecting plate. Weld the external connecting plate to the web of the secondary longitudinal steel beam GL2, with three-sided welding. After the cantilever secondary beam GL3 is installed, weld the Q235B L100×80×8 angle steel to the surface of the angle steel embedded part, with single-sided fillet weld connection. According to the floor deck layout diagram, lay the steel truss floor deck of the cantilever inner platform. After laying a certain area, tie the distribution steel bars.

[0017] S9: Cantilever platform slab pouring: After the steel truss floor deck is laid, the steel reinforcement of the cantilever platform slab is tied. The surface where the beams and columns in the non-cantilever area meet the cantilever platform needs to be roughened, cleaned and then cement slurry applied. After pouring, the formwork can be removed only after curing to the demolding strength.

[0018] S10: Monitoring and Verifying the Deflection of the Steel Beam: Using the sensor's inherent conversion formula and a previously developed and calibrated formula, the sensor's frequency values ​​are converted into strain units of the member, and then into end deflection perpendicular to the member's direction. This allows for the assessment of the member's end deformation.

[0019] Preferably, in step S4, when dismantling the formwork system in the non-cantilevered area, the three rows of two-span extended frame structures and corresponding reinforcements are retained. Simultaneously, 100×50×2.5 square steel pipe main keels are arranged on the three rows of uprights to temporarily support the hoisting of the steel beams.

[0020] Preferably, step S5 includes the following steps:

[0021] S51: Verification and analysis of cantilever structure lifting and installation: Considering the stress load during the installation process in the cantilever area, the safety factor is increased, the load value of the cantilever steel structure is taken, and the calculation is carried out considering the most unfavorable stress position;

[0022] S52: Verification and analysis of concrete pouring after installation of cantilever structure: Numerical simulation of the situation after installation of cantilever structure, loading of cantilever steel structure, amplification of safety factor, and calculation considering the most unfavorable stress position;

[0023] S53: Verification and analysis of the upper loading after the cantilever platform is poured: Numerical simulation is performed on the case of continued loading after the upper part of the cantilever platform is poured. The cantilever steel structure is subjected to continued loading, the safety factor is increased, and the most unfavorable stress position is considered for calculation.

[0024] Preferably, in step S6, before installing the beam-mounted scaffolding, wooden blocks are accurately placed on the base plate according to the position lines of the uprights of the scaffolding as indicated by the pop-up image. The concrete strength of the beams and slabs of the lower structure of the support system is not less than 1.2 MPa. The support frame is set on multiple floors, and the support on the floors below the load-bearing beams and slabs is not removed. The uprights are aligned vertically, and the spacing between the uprights is strictly in accordance with the plan. The verticality deviation of the uprights is not greater than 3H / 1000 and is not greater than 30 mm, where H is the erection height of the uprights.

[0025] Preferably, in step S10, the strain gauge is an AIOT-CCP-ZXS-CGQ-YB-03 vibrating wire surface strain gauge with a calibration coefficient of K=3.978. Calibration is performed using an AIOT-CCP-ZXS-CJY-SC-01 type readout instrument in the 400-1200 range. The calculation formula is: ε (micro-strain) = K(fi2-fo2) / 1000, where K is the instrument standard coefficient, fo is the initial reading, fi is the current reading in Hz, and fi is the temperature coefficient and temperature factor correction of the instrument.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] This invention relates to a composite structural system consisting of a composite floor slab, concrete frame beams, steel beams one, two, and three, and embedded steel beam components. By pre-installing embedded components on the concave non-cantilever structure adjacent to the cantilever structure, after the concrete in the non-cantilever area is poured and reaches its design strength, steel beams GL1 and GL2 in the steel-concrete composite structure are installed, supplemented by bottom supports. After the installation of steel beams GL1 and GL2, the formwork for the cantilever inner platform is erected and poured, forming a robust integrated structural system with the steel beams and concrete, increasing safety during the construction of the high-altitude cantilever outer platform. Finally, steel beam GL3 is installed, connecting the cantilever area to the structure as a whole, and the profiled steel sheet for the cantilever outer platform is laid before the concrete floor slab is poured. By using finite element software to simulate and analyze the deformation and strain of the combined structural system in advance, strain gauges are installed on the steel beams to monitor and collect data on the cantilever structure in real time. The collected data is processed and compared with the numerical simulation results in real time. When a large deviation is found, real-time correction is performed to guide on-site construction and ensure the structural safety throughout the installation process and under superloading, thus achieving pre-simulation analysis and in-process control.

[0028] This combined structural system utilizes the inherent unsupported nature of steel structures—pre-embedded components within a recessed, non-cantilevered concrete structure followed by the installation of steel beams—to form a unified structural system. The use of profiled steel sheet flooring facilitates unsupported construction of high-altitude cantilever structures, offering advantages such as safety, reliability, and ease of operation. Compared to temporary support erection in high-altitude cantilever areas, it provides convenience, cost-effectiveness, and time savings. Furthermore, finite element analysis software is used to simulate and analyze the deformation and strain of the cantilever structure, enabling more accurate prediction of steel deformation, avoiding design deviations, and identifying potential construction problems early for appropriate adjustments. Vibrating wire surface strain gauges are used to monitor the deformation and strain of the cantilever structure, allowing for timely detection and intervention to prevent severe deformation or damage. This system offers advantages such as improved design accuracy, reduced construction difficulty, and enhanced structural stability and safety. Attached Figure Description

[0029] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0030] Figure 1 This is a schematic diagram of the structure of the present invention;

[0031] Figure 2 This is a schematic diagram of the arrangement of the combined structural system of the present invention;

[0032] Figure 3 This is a schematic diagram of the planar partitioning of the present invention;

[0033] Figure 4 This is a schematic diagram of the planar construction of the present invention;

[0034] Figure 5 This is a schematic diagram of the temporary external scaffolding protection erection of the present invention.

[0035] Figure 6 This is a plan view of the embedded parts arrangement of the present invention;

[0036] Figure 7 This is a diagram of the hinged joint between the GL1 of this invention and the concrete beam;

[0037] Figure 8 This is a schematic diagram showing the position of the third lifting lug on the steel beam of the present invention;

[0038] Figure 9 This is a strain-displacement cloud diagram for the verification and analysis of the cantilever structure lifting and installation process of the present invention;

[0039] Figure 10 This is a strain-displacement cloud diagram for the concrete pouring verification analysis after the installation of the cantilever structure of the present invention;

[0040] Figure 11 This invention relates to a strain-displacement cloud diagram obtained from the superstructure loading verification analysis after the cantilever platform was poured.

[0041] Figure 12 This is a schematic diagram illustrating the construction method at the junction of the concrete beam and the steel beam in this invention;

[0042] Figure 13 This is a schematic diagram of the connection node between the floor deck and the concrete of the present invention;

[0043] Figure 14 This is a schematic diagram of the vertical displacement during the lifting and installation process of the cantilever structure of the present invention;

[0044] Figure 15 This is a schematic diagram of the vertical displacement of the concrete pouring after the cantilever structure of the present invention is installed;

[0045] Figure 16 This is a schematic diagram of the vertical displacement of the upper part after the cantilever platform of the present invention has been poured.

[0046] In the diagram, 1. Composite floor slab; 2. Concrete frame beam KL1; 3. Steel beam GL1; 4. Steel beam GL2; 5. Steel beam GL3; 6. Embedded parts of steel beams. Detailed Implementation

[0047] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the embodiments.

[0048] Reference Figures 1 to 16The present invention discloses a high-altitude cantilevered unsupported steel-concrete composite structure system based on numerical simulation, the structure of which includes: composite floor slab ①, concrete frame beam, steel beam one, steel beam two, steel beam three and steel beam embedded parts ⑥.

[0049] Composite floor slabs: Composite floor slabs utilize profiled steel sheets. These sheets not only serve as permanent formwork for the concrete slab, working together with the concrete to form the composite slab, but also eliminate the need for a bottom formwork system. A schematic diagram of the composite structural system layout is shown below. Figure 2 As shown, the composite structural system is divided into an inner cantilever platform and an outer cantilever platform, with KL1① as the boundary. The entire composite structural system is connected to the concave non-cantilever frame system, which includes KZ1, KL2, KL3, and L1. The inner cantilever platform is not part of the cantilever area and can be reliably supported below; however, the outer cantilever platform is a high-altitude cantilever area, making it difficult to erect a temporary support system below. The composite floor slabs are poured in sections sequentially from the non-cantilever area to the outer cantilever platform.

[0050] The steel beams are H-beams, with GL1③ and GL2④ being hoisted first. They are connected by welding to pre-embedded steel structural components embedded in the already poured non-cantilevered frame system that has reached the design strength. The concave design of the non-cantilevered area allows for the use of a support frame erected within the cantilevered inner platform as a platform for hoisting, welding, rebar tying, and pre-embedded components. Under reliable support, the cantilevered inner platform can be safely poured. At this point, GL1 and GL2 are integrated with the poured concrete slab, exhibiting excellent bending resistance and reliability. Once the concrete strength of the non-cantilevered area and the cantilevered inner platform reaches 100% of the design strength, GL3⑤ is hoisted. Finally, the profiled steel sheet of the cantilevered outer platform is laid, the floor slab rebar is tied, and concrete is poured.

[0051] Steel beam embedded parts: The steel beam embedded parts are pre-embedded in the frame system in the non-cantilever area and have been installed before the construction of the combined structural system.

[0052] This composite structural system consists of composite floor slabs, concrete frame beams, steel beams 1, 2, and 3, and embedded steel beam components. Embedded components are pre-placed on the recessed non-cantilever structure adjacent to the cantilever structure. After the concrete in the non-cantilever area is poured and reaches its design strength, steel beams GL1 and GL2 in the steel-concrete composite structure are installed, supplemented by bottom supports. After the installation of steel beams GL1 and GL2, the formwork for the cantilever inner platform is erected and poured, forming a robust integrated structural system with the steel beams and concrete, increasing safety during the construction of the high-altitude cantilever outer platform. Finally, steel beam GL3 is installed, connecting the cantilever area to the structure as a whole. The profiled steel sheet for the cantilever outer platform is then laid, and the concrete floor slab is poured. By using finite element software to simulate and analyze the deformation and strain of the combined structural system in advance, strain gauges are installed on the steel beams to monitor and collect data on the cantilever structure in real time. The collected data is processed and compared with the numerical simulation results in real time. When a large deviation is found, real-time correction is performed to guide on-site construction and ensure the structural safety throughout the installation process and under superloading, thus achieving pre-simulation analysis and in-process control.

[0053] This combined structural system utilizes the inherent unsupported nature of steel structures—pre-embedded components within a recessed, non-cantilevered concrete structure followed by the installation of steel beams—to form a unified structural system. The use of profiled steel sheet flooring facilitates unsupported construction of high-altitude cantilever structures, offering advantages such as safety, reliability, and ease of operation. Compared to temporary support erection in high-altitude cantilever areas, it provides convenience, cost-effectiveness, and time savings. Furthermore, finite element analysis software is used to simulate and analyze the deformation and strain of the cantilever structure, enabling more accurate prediction of steel deformation, avoiding design deviations, and identifying potential construction problems early for appropriate adjustments. Vibrating wire surface strain gauges are used to monitor the deformation and strain of the cantilever structure, allowing for timely detection and intervention to prevent severe deformation or damage. This system offers advantages such as improved design accuracy, reduced construction difficulty, and enhanced structural stability and safety.

[0054] The construction steps of this invention are as follows:

[0055] S1. Construction preparation: Component segment and section numbering

[0056] 1) Based on the design drawings, understand the design intent and depth, verify the material and component usage, and review the specifications, models, and materials of the components. Ensure that the design and specification requirements are met.

[0057] 2) Prepare a comprehensive construction plan and technical briefing.

[0058] 3) Based on the detailed construction drawings of the steel structure, number the embedded parts and components in both the non-cantilevered and cantilevered areas, see [reference needed]. Figure 3 .

[0059] S2. Erection of formwork system for non-cantilevered areas and cantilevered platforms.

[0060] The formwork system for non-cantilever areas is constructed with a horizontal bar spacing of 1500mm for the middle layer and 1000mm for the top layer, with a horizontal and vertical span of 1200mm. It utilizes a base plate, disc-lock formwork support frame, and U-shaped support top bracing. The main joists are made of 100×50×2.5 square steel pipes. The planar construction layout is shown below. Figure 4 When erecting the formwork system for non-cantilevered areas, the two extended spans serve as external scaffolding protection for the non-cantilevered areas. (Erection instructions follow.) Figure 5 .

[0061] S3. Installation and fixing of embedded parts in non-cantilevered areas and pouring of concrete.

[0062] 1) At the junction of the non-cantilevered area and the cantilevered platform, according to the design drawings, install embedded parts for the hinged joints between GL1 and the concrete beams, as well as embedded parts for the composite floor slab support angle steel, on the sides of beams KL1①, L1, and KL3. See the attached plan for the embedded parts layout. Figure 6 The joint between the steel beam and the concrete beam is shown in the figure. Figure 7 .

[0063] 2. On the structural column KZ1 at the junction of the non-cantilevered area and the cantilevered platform, and on the side of beam L1, pre-insert the main reinforcement bars of the cantilevered platform frame beam KL1① and beam L2. Pay special attention to the position of the second row of reinforcement bars in the KL1① concrete beam, ensuring that they are not lower than the upper surface of the upper flange of GL1. After the reinforcement bars are tied, when pouring concrete in the non-cantilevered area, take care to avoid loosening of the inserted reinforcement bars, which could lead to misalignment of the reinforcement bars on both sides.

[0064] 3. KL2, KL3, and L1 should be poured first after the reinforcement binding and embedded parts installation are completed. KL1① and L2 should be poured after the reinforcement binding and embedded parts installation are completed and GL1 is hoisted through KL1①, so as to ensure that the non-cantilever area is poured as a whole first.

[0065] S4, hoisting of cantilever platform steel beams GL1 and GL2

[0066] 1. In non-cantilevered areas, the structure can only be dismantled after the formwork has reached the design strength and the project department has issued a dismantling notice. Only after dismantling can the steel beams be hoisted.

[0067] 2. When dismantling the formwork system in the non-cantilevered area, retain the three rows of two-span extended frame structures and corresponding reinforcement components. Simultaneously, arrange square steel pipe main keels (□100×50×2.5) on the three rows of uprights to temporarily support the steel beam hoisting, preventing inaccurate installation or safety accidents caused by excessive deflection at the cantilevered ends during steel beam hoisting.

[0068] 3. Install a third lifting lug on steel beam GL1, approximately 1 meter from the end of the steel beam. See [link / details]. Figure 8 .

[0069] 4. The bottom support of beam KL1① has been set up on site. All the 60cm vertical supports on both sides of the beam and the top screw support under the beam are connected in the longitudinal and transverse directions. The spacing of the supports is set up in accordance with the requirements for the erection of the internal scaffold.

[0070] 5. Installation of steel beams GL1 and GL2:

[0071] Safety protection measures are in place, and the hoisting equipment meets the requirements → The steel beam is hoisted to the installation height position → Move and insert it into the middle of the upper and lower main bars of the concrete KL1① steel reinforcement on the operating platform until the steel reinforcement frame and the sling position interfere. Then, use the hoist chain to tie the end of the steel beam and make temporary fixation. Then, loosen one end of the hook and fix it to the position of the third lifting lug → After reinstalling the hoisting measures, continue to move the steel beam. At this time, the hoist chain can be loosened. The hook can only be loosened after the high-strength bolts at the end of the steel beam are completely fixed → After GL1 is installed, install GL2 → Install the remaining three GL1 beams (green steel beams in the figure) in sequence according to this method → ​​After all GL1 beams are installed, seal the side formwork of KL1① and pour concrete.

[0072] S5. Set the strain gauges based on the analysis results from the finite element analysis software.

[0073] Using the finite element software ANSYS, we modeled and calculated under different working conditions to simulate the stress and end displacement of the cantilever structure under different conditions throughout the construction stage. Based on the design drawings and the actual site conditions, we established a finite element model.

[0074] 1) Verification and analysis of the lifting and installation of the cantilever structure

[0075] Considering the stress loads during installation in the cantilevered area, and with an increased safety factor, load values ​​were determined for the cantilevered steel structure. Calculations were performed considering the most unfavorable stress locations, and the verification results are as follows: Figure 9 As shown.

[0076] 2) Verification and analysis of concrete pouring after installation of cantilever structure

[0077] Numerical simulations were performed on the cantilever structure after installation. The cantilever steel structure was loaded, a safety factor was increased, and the most unfavorable stress location was considered in the calculations. The verification results are as follows: Figure 10 As shown.

[0078] 3) Load verification analysis of the cantilever platform after pouring

[0079] Numerical simulations were performed to simulate the scenario where loading continues after the upper part of the cantilever platform has been poured. The cantilever steel structure was subjected to further loading, the safety factor was increased, and the most unfavorable stress location was considered in the calculations. The verification results are as follows: Figure 11As shown.

[0080] Conclusion: Under different loading conditions, the maximum cantilever deformation, as determined by finite element numerical simulation software, is 29.69 mm, which is less than L / 200 = 2500 * 2 / 200 = 25 mm. This meets the requirements of the steel structure design code. After identifying the point of maximum deformation, strain gauges were installed at this point after the steel beam was installed. Fixed-point, timed monitoring of the most unfavorable point was then conducted, achieving pre-simulation analysis and in-process control. This principle provides better forward-looking guidance for on-site installation work, ensuring structural safety.

[0081] S6, cantilevered inner platform beam KL1①, L2 formwork support

[0082] 1) After the steel beams are hoisted, erect the cantilevered inner platform structure beam scaffolding and support the concrete structure beam formwork.

[0083] 2) Before installation, accurately place wooden blocks on the base plate according to the position lines of the uprights of the disc-lock scaffold. The concrete strength of the beams and slabs of the supporting system should not be less than 1.2MPa before the formwork support frame can be erected. If the support frame is set on a multi-story slab, the support on the floors below the load-bearing beams and slabs must not be removed, and the vertical axis of the uprights must correspond vertically.

[0084] 3) The spacing between the scaffold uprights must be strictly in accordance with the plan. After each step of the scaffold is erected, its straightness, levelness, and verticality, as well as the step spacing of the uprights, should be checked and adjusted immediately. The verticality deviation of the uprights should be controlled to be no greater than 3H / 1000 and no greater than 30mm, where H is the erection height of the uprights.

[0085] S7, Reinforcement binding and pouring of cantilever inner platform beams KL1① and L2

[0086] First, tie the reinforcing bars of the concrete structural beam KL1① that intersects with the steel beam GL1. The main reinforcement bars of the beam are mechanically connected to the dowel bars on both sides through the reinforcement sleeves. Note that the web reinforcement bars of the main beam should pass through the Φ24 holes reserved in the web of the steel beam. Weld studs to the top of the steel beam to support the upper reinforcement bars of the beam, and add 4 rows at the bottom of the steel beam. Additional reinforcement of 14. The bottom and sides of the steel beam within a 150mm area are designated as a stirrup reinforcement zone, spaced 50mm apart. The construction details at the junction of the concrete beam and the steel beam are as follows: Figure 12 As shown.

[0087] S8, GL3 steel beam installation and cantilever platform steel truss floor decking laying

[0088] 1. The cantilevered secondary beam GL3 at the end can only be installed after the concrete strength of KL1① reaches 70%. Connect the longitudinal steel beam GL3 of the secondary beam to the extended connecting plate of the main beam GL1. Secure the secondary beam to the extended connecting plate with three M20 high-strength bolts. Weld the connecting plate to the web of the longitudinal steel beam GL2 of the secondary beam, with three-sided welding and a weld leg height of not less than 6mm.

[0089] 2. After the GL3 cantilever secondary beam of the end cap is installed, weld the Q235B angle steel of model L100×80×8 to the surface of the angle steel embedded part, with a single-sided fillet weld connection and a weld leg height of not less than 8mm.

[0090] 3. According to the floor decking layout diagram, lay the cantilevered inner platform steel truss floor decking. After laying a certain area, tie the distribution reinforcement to prevent lateral instability of the steel truss. Note that the load-bearing reinforcement of the slab is embedded in the beams in the non-cantilever area, and the connection nodes between the floor decking and the structure, such as... Figure 13 As shown.

[0091] S9, Cantilevered Platform Slab Casting

[0092] 1. After the steel truss floor deck is laid, the reinforcing steel of the cantilever platform slab should be tied. The surface where the beams and columns in the non-cantilever area meet the cantilever platform should be roughened, cleaned, and coated with cement slurry. During concrete pouring, the local accumulation height should not exceed 200mm to prevent impact on the floor deck when pouring concrete. Before concrete pouring, any construction activities on the slab surface must not damage the cross-sectional shape of the floor deck. No concentrated loads should be placed on the floor before the concrete reaches its design strength. Before pouring concrete, grease, dirt, and other harmful substances on the floor deck should be thoroughly cleaned.

[0093] 2. After pouring, the formwork can be removed only after it has been cured to the required strength for demolding.

[0094] S10. Monitor and verify the deflection deformation of the steel beam.

[0095] The sensor can transmit real-time data. Using the sensor's inherent conversion formula and a formula that has been developed and calibrated beforehand, the sensor's frequency value is converted into the strain unit of the rod, and then into the end deflection perpendicular to the direction of the rod. This allows us to understand the deformation at the end of the component.

[0096] The strain gauge selected is the AIOT-CCP-ZXS-CGQ-YB-03 vibrating wire surface strain gauge (standard type). The strain gauge calibration coefficient is K=3.978. Calibration was performed using an AIOT-CCP-ZXS-CJY-SC-01 type readout instrument in the 400-1200 range. The calculation formula is as follows:

[0097] ε (micro-strain) = K(fi² - fo²) / 1000

[0098] The strain value within the measurement area is obtained.

[0099] In the formula, K is the instrument standard coefficient, fo is the initial reading, and fi is the current reading in Hz. The temperature coefficient and temperature factor correction of the instrument are as follows: This strain gauge does not need to be corrected if it is installed on a steel structure, because the steel wire of the sensor and the steel structure have the same coefficient of thermal expansion, so no correction is required.

[0100] During the construction of the cantilever structure, data was collected at least twice daily from the end of the largest cantilever. The collected data was then converted using formulas to obtain the vertical displacement changes at the end. Figure 14 , Figure 15 and Figure 16 .

[0101] As can be seen from the figure, the measured maximum end displacement matches the simulated maximum end displacement well, indicating that the finite element model has certain guiding significance for engineering practice.

[0102] This invention solves the technical problem of conventional cantilever structure construction, which requires the erection of temporary triangular support systems or steel platform support systems under the cantilever structure. It designs a steel-concrete composite structure system connected to the concave non-cantilever area. Through segmented construction deployment, utilizing the inherent property of steel structures that require no temporary support, a unified structural system is formed, meeting the construction requirements of high-altitude cantilever structures. This system offers advantages such as safety, reliability, and ease of operation. Compared to erecting temporary supports in high-altitude cantilever areas, it provides advantages such as convenient construction, economic efficiency, and reduced construction time. Furthermore, through simulation analysis and deformation monitoring of the steel structure, it offers advantages such as improved design accuracy, reduced construction difficulty, and enhanced structural stability and safety.

[0103] As described above, although the invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A high-altitude cantilevered unsupported steel-concrete composite structure system based on numerical simulation, characterized in that: This includes an inner cantilever platform and an outer cantilever platform connected to the concave non-cantilever area frame system, with the inner and outer cantilever platforms separated by a concrete frame beam KL1. The non-cantilever area frame system includes structural column KZ1, concrete frame beams KL2 and KL3, and beam L1 at the junction of the non-cantilever area and the cantilever platform. A reliable support platform is erected beneath the inner cantilever platform to facilitate hoisting, welding, rebar tying, and pre-embedded construction procedures. The transition from the non-cantilever area to the outer cantilever platform is segmented sequentially. A composite floor slab is poured, and steel beam embedded parts are fixedly installed on the non-cantilevered area frame system. The steel beam embedded parts are fixed to the steel beams, which include steel beam GL1, steel beam GL2, and steel beam GL3. Steel beam GL1 and steel beam GL2 form a solid integral structure with the concrete in the non-cantilevered area, and steel beam GL3 connects the cantilevered area with the integral structure. The system also includes finite element software for pre-simulation and analysis of the deformation and strain results of the composite structure system. The finite element software includes strain gauges installed on the steel beams.

2. The high-altitude cantilevered unsupported steel-concrete composite structure system based on numerical simulation according to claim 1, characterized in that: The composite floor slab is formed by the joint action of profiled steel sheet and concrete.

3. The high-altitude cantilevered unsupported steel-concrete composite structure system based on numerical simulation according to claim 2, characterized in that: The steel beams are made of H-beams.

4. A construction method comprising the high-altitude cantilevered unsupported steel-concrete composite structure system as described in any one of claims 1 to 3, characterized in that, The steps are as follows: S1: Construction preparation, component segmentation and numbering: Check the material component usage according to the design drawings, verify the specifications, models and materials of the components, prepare a complete construction plan and technical briefing, and number the embedded parts and components in non-cantilever and cantilever areas according to the steel structure detailed construction drawings. S2: Erection of formwork system for non-cantilevered areas and cantilevered platforms: The formwork system for non-cantilevered areas is erected according to the following: the horizontal bar spacing of the middle layer is 1500mm, the horizontal bar spacing of the top layer is 1000mm, the horizontal and vertical span is 1200mm, and the formwork system for non-cantilevered areas is erected using pads, disc-type formwork support frames and U-shaped support top supports. The main keel is made of 100×50×2.5mm square steel pipe. When erecting the formwork system for non-cantilevered areas, the two extended spans serve as external scaffolding protection for non-cantilevered areas. S3: Installation and Pouring of Embedded Parts in Non-Cantilever Areas: At the junction of the non-cantilever area and the cantilever platform, according to the design drawings, embedded parts for the hinged joint between steel beam GL1 and the concrete beam, as well as embedded parts for the composite floor slab support angle steel, are installed on the sides of concrete frame beams KL1, L1, and KL3. On the structural column KZ1 at the junction of the non-cantilever area and the cantilever platform, and on the side of beam L1, the main reinforcement bars of cantilever platform frame beams KL1 and L2 are pre-inserted. After the reinforcement bars are tied, concrete is poured in the non-cantilever area. Concrete frame beams KL2, KL3, and L1 are poured first after the reinforcement bars are tied and the embedded parts are installed. After the reinforcement bars of concrete frame beams KL1 and L2 are tied and the embedded parts are installed, concrete is poured after steel beam GL1 is hoisted through concrete frame beam KL1. S4: Hoisting of steel beams GL1 and GL2 on the cantilever platform: After the non-cantilever area structure has reached its design strength, it will be dismantled. A third lifting lug will be installed on steel beam GL1, and a third lifting lug will be installed 1m from the end of the steel beam. At the same time, the bottom support of the concrete frame beam KL1 has been erected on site. All beams are supported by 60cm vertical poles on both sides, and the support frame with top screws is connected longitudinally and laterally. Safety protection measures are in place, and the hoisting equipment meets the requirements. The steel beam is hoisted to the installation height position, moved on the operating platform, and inserted into the concrete frame beam KL1. From the middle of the upper and lower main reinforcing bars, up to the point where the reinforcing bar frame and the sling interfere with each other, use a hoist chain to tie the end of the steel beam and temporarily fix it. Then loosen one end of the hook and fix it to the position of the third lifting lug. After reinstalling the hoisting measures, continue to move the steel beam. At this time, the hoist chain can be loosened. Only after the high-strength bolts at the end of the steel beam are completely fixed can the hook be loosened. After steel beam GL1 is installed, install steel beam GL2. Install the remaining three steel beams GL1 in sequence according to this method. After all steel beams GL1 are installed, seal the side formwork of the concrete frame beam KL1 and pour concrete. S5: Set up strain gauges based on the analysis results of finite element software: Use the finite element software ANSYS to model and load calculations for different working conditions, simulate the stress and end displacement of the cantilever structure under different conditions throughout the construction stage, and establish a finite element model based on the design drawings and actual site conditions. S6: Formwork support for the cantilevered inner platform concrete frame beams KL1 and L2: After the steel beams are hoisted, erect the cantilevered inner platform structural beam scaffolding and support the concrete structural beam formwork. S7: Reinforcement binding and pouring of concrete frame beams KL1 and L2 for the cantilevered inner platform: First, bind the reinforcement of concrete frame beam KL1, which intersects with steel beam GL1. The main reinforcement of the beam is mechanically connected to the dowel bars on both sides through reinforcement sleeves. Pass the web reinforcement of the main beam through the Φ24 holes reserved in the web of the steel beam. Weld studs to the top of the steel beam to support the upper reinforcement of the beam, and add 4 rows at the bottom of the steel beam. Additional reinforcement of 14, the bottom and 150mm sides of the steel beam are the stirrup reinforcement zone, with a spacing of 50mm; S8: Installation of steel beam GL3 and laying of steel truss floor deck for cantilever platform: Connect the secondary longitudinal steel beam GL3 to the extended connecting plate of steel beam GL1. Secure the secondary steel beam to the extended connecting plate with 3 M20 high-strength bolts. Weld the connecting plate to the web of secondary longitudinal steel beam GL2 with three-sided welding. After the cantilever secondary steel beam GL3 is installed, weld the Q235B L100×80×8mm angle steel to the surface of the angle steel embedded part with single-sided fillet weld. According to the floor deck layout diagram, lay the steel truss floor deck of the cantilever inner platform. After laying a certain area, tie the distribution steel bars. S9: Cantilever platform slab pouring: After the steel truss floor deck is laid, the steel reinforcement of the cantilever platform slab is tied. The surface where the beams and columns in the non-cantilever area meet the cantilever platform needs to be roughened, cleaned and then cement slurry applied. After pouring, the formwork can be removed only after curing to the demolding strength. S10: Monitoring and verifying the deflection of the steel beam: Using the sensor's inherent conversion formula and the formula that has been developed and verified in advance, the frequency value of the sensor is converted into the strain unit of the rod, and then converted into the end deflection perpendicular to the direction of the rod.

5. A construction method according to claim 4, characterized in that: In step S4, when dismantling the formwork system in the non-cantilevered area, the three rows of two spans of the outward-extending frame and the corresponding reinforcements are retained. At the same time, square steel pipe main keels with specifications of 100×50×2.5mm are arranged on the three rows of uprights to temporarily support the hoisting of the steel beams.

6. A construction method according to claim 5, characterized in that: Step S5 includes the following steps: S51: Verification and analysis of cantilever structure lifting and installation: Considering the stress load during the installation process in the cantilever area, the safety factor is increased, the load value of the cantilever steel structure is taken, and the calculation is carried out considering the most unfavorable stress position; S52: Verification and analysis of concrete pouring after installation of cantilever structure: Numerical simulation of the situation after installation of cantilever structure, loading of cantilever steel structure, amplification of safety factor, and calculation considering the most unfavorable stress position; S53: Verification and analysis of the upper loading after the cantilever platform is poured: Numerical simulation is performed on the case of continued loading after the upper part of the cantilever platform is poured. The cantilever steel structure is subjected to continued loading, the safety factor is increased, and the most unfavorable stress position is considered for calculation.

7. A construction method according to claim 6, characterized in that: In step S6, before installing the beam-mounted scaffolding, accurately place wooden blocks on the base plate according to the position lines of the uprights of the scaffolding as indicated by the pop-up diagram. The concrete strength of the beams and slabs of the supporting system should not be less than 1.2MPa. The support frame should be set on multiple floors. The support on floors below the load-bearing beams and slabs should not be removed. The axes of the uprights should correspond vertically. The spacing between the uprights should be strictly in accordance with the plan. The verticality deviation of the uprights should not be greater than 3H / 1000 and should not be greater than 30mm. H is the erection height of the uprights.

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