Ultra-high space large-span truss floor support plate construction top-free supporting structure and method

Abstract

The invention relates to a top-free supporting structure and method for construction of an ultrahigh-space large-span truss floor support plate, which are characterized in that expansion is carried out on the basis of a stress form that a suspender is used as a suspension cable support, and a supporting and hanging system consisting of three bearing components, namely the suspender, a suspension beam and a supporting leg is formed by combining a unique composition structure and a connection mode of the steel bar truss floor support plate. And after the truss floor support plates are laid and corrected, stud welding is completed, the suspension beams and the supporting legs at the upper end are assembled, then the supporting legs are welded to the structural steel beams at the lap joint positions of the floor support plates, and the large-span truss floor support plates are tied in a suspender connecting mode. A force transmission path of the floor support plate, the suspenders, the suspension beams, the supporting legs and the structural steel beams is formed, the overall construction load is finally transmitted to the structural main steel beams, deformation downwarping and instability caused by the too large span of the floor support plate are resisted, and the purpose that the large-span truss floor support plate is free of back shore is achieved. The problem of temporary supporting of the truss floor support plate under the working condition of coexistence of ultrahigh space and large span is effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, and more particularly to a top-free support structure and method for the construction of an ultra-high space large-span truss floor deck. Background Art

[0002] As the mainstream design of comprehensive public buildings, steel truss floor decks have been widely used. However, when the span exceeds the support-free range of the floor deck, its own bearing capacity is insufficient to bear its own weight and construction load, resulting in the inevitable deflection and instability of the mid-span position of the floor deck. In order to prevent the deflection of the floor deck and ensure its overall rigidity and stability, temporary supports are usually set under the floor deck before concrete pouring. The traditional temporary support erection method uses a support system in the form of steel pipes or buckles, which has the following problems:

[0003] 1. A large amount of turnover materials is required, which increases the cost.

[0004] 2. The installation and disassembly process is complicated and time-consuming.

[0005] 3. The support system occupies a large area, affecting other operations on site.

[0006] 4. In ultra-high space locations, temporary support frames are limited by space, and the height-to-width ratio is often relatively large, even exceeding the 3:1 regulatory limit, making it difficult to ensure overall stability and safety.

[0007] 5. The erection of the frame is also limited by the actual strength of the lower floor slab. If a certain strength is not reached, the support frame cannot be erected, and the purpose of rapid insertion of super-high-rise floor slab pouring cannot be achieved.

[0008] 6. More and more comprehensive public buildings are beginning to adopt the design concept of "empty first floor and daylighting in the atrium", forming a special working condition of super-high and large span. Under such working conditions, traditional temporary support not only delays time and wastes materials, but also has a high construction risk factor.

[0009] 7. Although the purpose of no support can be achieved by reducing the spacing between the main beams or secondary beams, it will inevitably increase the amount of material used, which is not worth the cost.

[0010] In view of the above construction difficulties, how to provide a top-free support structure and method for the construction of ultra-high space large-span truss floor decking is a problem that technical personnel in this field urgently need to solve. Summary of the invention

[0011] To this end, an object of the present invention is to propose a method for constructing ultra-high space large-span truss floor decking without top support, so as to solve the above-mentioned problem caused by setting temporary support under the floor decking before concrete pouring.

[0012] Another object of the present invention is to provide a top-free support structure for the construction of ultra-high space large-span truss floor decks, which is used to temporarily support the floor decks to resist deformation, deflection and instability of the floor decks caused by excessive span.

[0013] The solution of the present invention is a method for constructing a super-high space large-span truss floor deck without top support, comprising the following steps:

[0014] S1. Layout the floor decking according to the design requirements and specifications, and define the temporary support area; lay the floor decking on site according to the layout drawing;

[0015] S2. Analyze the temporary support area in combination with the building structure and on-site working conditions; use the method of hanging the floor slab under the reverse support cantilever beam to resist the deformation, deflection and instability of the floor slab caused by the large span;

[0016] S3. Design the system and layout of the suspended floor deck under the inverted cantilever beam. The system at least includes cantilever beams, outriggers, and hangers, forming a force transmission path from the floor deck, hangers, cantilever beams, outriggers to the structural steel beams; determine the material consumption according to the design scheme, and carry out cutting and processing;

[0017] S4. Determine the plane position of the cantilever beam and the height of the outriggers by on-site layout according to the design plan; then fix the outriggers to the cantilever beam and hoist the cantilever beam to the construction floor for precise layout;

[0018] S5. After the suspension beam is accurately arranged, connect the hanger rod with the suspension beam and the upper chord steel bars of the floor deck;

[0019] S6. Concrete pouring and curing;

[0020] S7. When the concrete strength reaches 75%, cut the hanger rod and remove the cantilever beam.

[0021] According to the method of the present invention, in S4, a cantilever beam is arranged in the middle of the span of the floor deck.

[0022] According to the method of the present invention, in S4, the suspension beam is first placed on the ground, and after the legs on both sides are fully welded to the lower flange of the suspension beam, the suspension beam is flipped 180° and erected, and then the joints between the legs and the upper flange of the suspension beam are fully welded, and the weld height and width are not less than 5 mm and 10 mm respectively.

[0023] According to the method of the present invention, after the welding of the legs is completed, the suspension beam with the legs is hoisted to the construction layer, and the bottom of the legs is spot-welded and fixed to the structural steel beam according to the precise arrangement of the measurement points.

[0024] According to the method of the present invention, after the cantilever beams are arranged and fixed in S5, the cantilever beams are connected to the floor decking plates, and each hanger rod is arranged in the middle of a single floor decking plate and arranged at equal intervals.

[0025] According to the method of the present invention, when the hanger is installed, it is arranged opposite and staggered relative to the center line of the suspension beam, the upper part of the hanger is welded and fixed to the upper flange and lower flange of the suspension beam, and the lower part of the hanger is welded and connected to the upper chord steel bars and steel plates of the floor decking.

[0026] According to the method of the present invention, before pouring concrete in S6, the connection quality of the cantilever beam, the legs and the hanger, as well as the cantilever beam position and the hanger rod spacing should be inspected and accepted, and concrete pouring is carried out after passing the acceptance inspection; the pouring method adopts a continuous pouring process starting from one end by gradually withdrawing the pipe, and a flat vibrator and a vibrating rod are used simultaneously during pouring. At the end of pouring, a line is pulled through to control the concrete elevation of the floor slab, and maintenance is carried out in a timely manner after the surface is completed, and the maintenance time is not less than 7 days.

[0027] According to the method of the present invention, when cutting the hanger rod in S7, the cutting is performed along the structural elevation of the floor slab to ensure that the cross section of the hanger rod is not higher than the structural elevation of the floor slab after the cutting is completed.

[0028] The present invention also provides a top-free support structure for the construction of an ultra-high space large-span truss floor deck, comprising:

[0029] Cantilever beams are arranged in the mid-span of the floor deck in the temporary support area;

[0030] At least two groups of legs are fixed to the two ends of the cantilever beam, and the bottom of each leg is fixed to the structural steel beam;

[0031] A plurality of hangers are staggeredly arranged along both sides of the suspension beam, and the hangers arranged oppositely on both sides are set at equal intervals. The top of each hanger is fixed to the upper flange and the lower flange of the suspension beam, and the bottom thereof is connected to the upper chord steel bar and the steel plate of the floor decking.

[0032] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] This invention breaks through the traditional "support" thinking mode and proposes an innovative method of replacing "support" with "hanging", forming a construction design for ultra-high space large-span truss floor decking without top support. It effectively solves the problem of temporary support of truss floor decking under the coexistence of ultra-high space and large span, and has significantly improved progress, cost, safety, environmental protection and other aspects, which is in line with the development rhythm of the current construction industry. At the same time, it also opens up a new way for the construction technology of ultra-high space large-span truss floor decking.

[0034] The present invention is expanded on the basis of the force form of the hanger as the cable support, and combined with the unique composition structure and connection method of the steel truss floor deck, a support and suspension system composed of three major load-bearing components: hangers, suspension beams, and outriggers is formed. After the truss floor deck is laid and corrected and the bolts are welded, the upper end suspension beams and outriggers are assembled, and then the outriggers are welded to the structural steel beams at the overlap of the floor deck, and the large-span truss floor deck is tied by connecting the hangers. A force transmission path is formed from floor deck → hanger → suspension beam → outrigger → structural steel beam, and the overall construction load is finally transmitted to the main steel beam of the structure, resisting the deformation, deflection and instability of the floor deck caused by the large span, and achieving the purpose of freeing the large-span truss floor deck from top support. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0036] Figure 1 A top view of the top-free support structure for the construction of the ultra-high space large-span truss floor deck provided by the present invention;

[0037] Figure 2 The side view of the top-free support structure for the construction of the super-high space large-span truss floor deck is shown;

[0038] Figure 3 This is a schematic diagram of the installation of the suspension beam, outriggers and suspenders;

[0039] Figure 4 The schematic diagram of welding the lower flange of the cantilever beam to the legs is shown;

[0040] Figure 5 A schematic diagram showing the welding of the upper flange of the cantilever beam and the support leg is shown. DETAILED DESCRIPTION

[0041] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0042] In the description of the present invention, it is necessary to understand that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0043] In the prior art, in order to prevent the steel truss floor deck from deflecting and ensure its overall rigidity and stability when the span exceeds its support-free range, temporary supports are usually set under the floor deck before concrete pouring. The traditional temporary support erection method uses a support system in the form of steel pipes or disc buckles, which has many shortcomings. In view of this, the present invention provides a method for constructing a large-span truss floor deck in an ultra-high space without top support, including the following steps:

[0044] S1. Layout the floor decking according to the design requirements and specifications, and define the temporary support area; lay the floor decking on site according to the layout drawing;

[0045] S2. Analyze the temporary support area in combination with the building structure and on-site working conditions; use the method of hanging the floor slab under the reverse support cantilever beam to resist the deformation, deflection and instability of the floor slab caused by the large span;

[0046] S3. Design the system and layout of the suspended floor deck under the inverted cantilever beam. The system at least includes cantilever beams, outriggers, and hangers, forming a force transmission path from the floor deck, hangers, cantilever beams, outriggers to the structural steel beams; determine the material consumption according to the design scheme, and carry out cutting and processing;

[0047] S4. Determine the plane position of the cantilever beam and the height of the outriggers by on-site layout according to the design plan; then fix the outriggers to the cantilever beam and hoist the cantilever beam to the construction floor for precise layout;

[0048] S5. After the suspension beam is accurately arranged, connect the hanger rod with the suspension beam and the upper chord steel bars of the floor deck;

[0049] S6. Concrete pouring and curing;

[0050] S7. When the concrete strength reaches 75%, cut the hanger rod and remove the cantilever beam.

[0051] The present invention is expanded on the basis of the force-bearing form of the hanger as the cable support, and combined with the steel truss floor deck, a support and suspension system consisting of three major load-bearing components: the hanger, the suspension beam, and the support leg. The force transmission path is from the floor deck → hanger → suspension beam → support leg → structural steel beam, and the overall construction load is finally transmitted to the main steel beam of the structure, resisting the deformation, deflection and instability of the floor deck caused by the large span, thereby achieving the purpose of eliminating the need for top support for the large-span truss floor deck.

[0052] Advantageously, the arrangement of cantilever beams in the mid-span of the floor deck in S4 can significantly improve the overall stability of the structure. The cantilever beams transfer the load to the main steel beams through hangers and legs, effectively resisting the deformation and deflection of the floor deck caused by excessive span. The arrangement of cantilever beams in the mid-span of the floor deck helps to disperse the concentrated load on the floor deck and avoid structural damage caused by excessive local force. This design can distribute the load more evenly and improve the bearing capacity of the entire floor deck. The arrangement of cantilever beams in the mid-span of the floor deck can significantly enhance the bending stiffness of the floor deck. The combined structure of cantilever beams and hangers increases the rigidity of the floor deck, making it more stable during construction and use.

[0053] In the embodiment of the present invention, in S4, the suspension beam is first placed on the ground, and the legs on both sides are fully welded to the lower flange of the suspension beam, and then the suspension beam is turned 180 degrees and erected, and then the seams between the legs and the upper flange of the suspension beam are fully welded, and the height and width of the weld are not less than 5mm and 10mm respectively. Figure 4 and 5 .

[0054] After the outriggers are welded, the cantilever beam with outriggers will be hoisted to the construction floor, precisely arranged according to the measured points, and the bottom of the outriggers will be spot welded to the structural steel beam.

[0055] In the embodiment of the present invention, after the cantilever beam is arranged and fixed in S5, the cantilever beam is connected to the floor decking plate, and each hanger is arranged in the middle of a single floor decking plate and arranged at equal intervals. When the hangers are installed, they are arranged opposite and staggered relative to the position of the center line of the cantilever beam. The upper part of the hanger is welded and fixed to the upper flange and the lower flange of the cantilever beam, and the lower part of the hanger is welded and connected to the upper chord steel bar and steel plate of the floor decking plate.

[0056] In this embodiment, the opposite and staggered arrangement of the hangers helps to disperse the load and avoid excessive local stress, thereby improving the stability and deformation resistance of the overall structure. This arrangement can effectively resist deformation and deflection caused by excessive span of the floor deck. The arrangement of the hangers enhances the bending rigidity of the floor deck, making it more stable during construction and use. The hangers are connected to the suspension beams and the floor deck by welding to form a solid support system.

[0057] The layout of the hangers optimizes the load transfer path, allowing the load to be transferred to the main steel beam more directly and effectively. This design not only improves the mechanical properties of the structure, but also enhances the overall safety and reliability.

[0058] The opposite and staggered arrangement of the hangers makes it more convenient for construction workers to install and weld the hangers, which is conducive to ensuring the quality and progress of construction. The firm connection between the hangers, suspension beams and floor decking enhances the durability of the entire structure and extends its service life.

[0059] In an embodiment of the present invention, before pouring concrete in S6, the connection quality of the cantilever beam, the legs and the hanger, as well as the cantilever beam position and the hanger rod spacing should be inspected and accepted, and concrete pouring is carried out only after passing the acceptance inspection; the pouring method adopts a continuous pouring process starting from one end and gradually withdrawing the pipe, and a flat vibrator and a vibrating rod are used simultaneously during pouring. At the end of pouring, a line is pulled through to control the floor slab concrete elevation, and maintenance is carried out in a timely manner after the surface is completed, and the maintenance time is not less than 7 days.

[0060] When cutting the hanger in S7, the cut is made along the structural elevation of the floor slab to ensure that the cross section of the hanger is not higher than the structural elevation of the floor slab after the cut is completed.

[0061] See attached Figure 1-3 , the structure used in the above method includes:

[0062] Cantilever beam 1, arranged in the middle of the span of the floor deck 4 in the temporary support area;

[0063] At least two groups of legs 2 are fixed to the two ends of the cantilever beam 1, and the bottom of each leg 2 is fixed to the structural steel beam 5;

[0064] Multiple hangers 3 are staggeredly arranged along both sides of the suspension beam 1, and the hangers 3 arranged oppositely on both sides are set at equal intervals. The top of each hanger 3 is fixed to the upper flange 11 and the lower flange 12 of the suspension beam 1, and the bottom thereof is connected to the upper chord steel bars and steel plates of the floor decking slab 4.

[0065] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] In order to specifically illustrate the method and structure of the present invention, in a specific embodiment of the invention, the concrete strength grade of the floor deck is C35 in the design stage, the upper and lower chord steel bars are hot-rolled steel bars HRB400 grade, the web bar steel bars are cold-rolled round steel bars, and the bottom mold yield strength is not less than 250N / mm 2 The maximum floor deck span calculated based on different floor deck models and deck thicknesses is shown in the following table:

[0067]

[0068] When deepening the drawings, we follow the specifications and design requirements and define the temporary support area in the floor decking layout according to the span of different steel beams. After the detailed drawings are confirmed, material processing and production are scheduled, and the floor decking is laid on site according to the floor decking layout.

[0069] During the working condition analysis, after the floor decking is laid, the temporary support area is analyzed in combination with the building structure and on-site working conditions. Take the laying of the three-story floor decking of the project as an example: in order to achieve the lighting effect of the atrium, a cantilever design is made on the first floor, resulting in a temporary support height of 12m. Since the first floor is the main material transportation channel, setting up temporary supports is not only difficult but also occupies space and restricts on-site material transportation.

[0070] The design scheme was inspired by the design of a suspension bridge. A suspension beam was set above the floor deck, and then square steel legs were welded at both ends of the suspension beam to support the suspension beam on the structural secondary steel beams on both sides. Hangers were then arranged at equal intervals along the direction of the suspension beam. Finally, the hangers were connected to the upper chord steel bars of the steel truss floor deck by welding, and the self-weight of the reinforced concrete and the construction load were transferred to the main structure through a new force transmission path. This scheme does not use the lower support method and is not limited by whether the upper structure has load-bearing components. It is convenient for construction and saves labor and materials.

[0071] According to the design working conditions of the above embodiment, the temporary support area on one side of the third floor is analyzed. The span of the floor deck is 4000mm, the spacing of the steel beams perpendicular to the laying direction of the floor deck is 5000mm, and a cantilever beam 1 is arranged in the middle of the span of the floor deck. The cantilever beam 1 adopts 16# I-beam, and the legs 2 at both ends of the cantilever beam 1 each use two 40×40×2.5mm square steel pipes, and the hanger rods are made of Φ8 steel bars, which are arranged at a spacing of 600mm.

[0072] The plane position of the cantilever beam is determined by on-site layout according to the plan layout drawing, and then the height of the cantilever beam legs is calculated according to the bottom elevation of the cantilever beam being 200mm away from the finished surface of the floor structure: 120mm (floor thickness) + 200mm + 160mm (16# I-beam height) = 480mm.

[0073] Calculate the material consumption according to the construction drawings and plans, and cut and process the materials. The square steel pipes (legs) and steel bars (suspenders) are all on-site waste materials, and can be cut appropriately according to the size on site. Place the cantilever beam 1 on the ground, first fully weld the legs 2 on both sides to the lower flange 12 of the cantilever beam 1, then flip the cantilever beam 180° and stand it up, and then fully weld the joints between the legs 2 and the upper flange 11 of the cantilever beam 1. The height and width of the weld should not be less than 5mm and 10mm respectively. After the leg 2 is welded, it will be hoisted to the construction floor, and accurately arranged according to the measurement points, and the bottom of the leg 2 will be spot welded to the structural steel beam 5 to prevent displacement caused by disturbance during the concrete pouring process.

[0074] After the suspension beam is arranged and fixed, the suspension beam 1 is connected to the floor deck 4. Since each floor deck 4 is 600mm wide, the suspension rod 3 is set in the middle of the floor deck 4, so the spacing of the suspension rods 3 is also arranged at an equal spacing of 600mm. In order to prevent the eccentric force of the suspension beam, the suspension rods 3 are arranged in a "one left and one right" manner to ensure uniform force on the left and right. The upper part of the suspension rod 3 is welded and fixed to the upper and lower flanges of the suspension beam 1, and the lower part is welded and connected to the upper chord steel bar and steel plate of the floor deck 4.

[0075] Before pouring concrete, the connection quality of cantilever beam 1, leg 2, and hanger 3, as well as the position of cantilever beam 1 and the spacing of hanger 3 should be inspected and accepted. Concrete pouring can only be carried out after passing the inspection and acceptance. The pouring method adopts the "rushing slurry method" to gradually withdraw the pipe from one end and continuously. When pouring, a flat vibrator and a vibrating rod are used at the same time. The vibrating points are arranged in a plum blossom shape with a spacing of 400mm. At the end of pouring, a line is pulled to control the concrete elevation of the floor slab. After the surface is completed, maintenance is carried out in time, and the maintenance time is not less than 7 days.

[0076] When the concrete strength reaches 75%, the hanger is cut off and the cantilever beam is removed. When cutting the hanger, a grinding wheel cutter is used to cut along the structural elevation of the floor to ensure that the cross-section of the hanger is not higher than the structural elevation of the floor after cutting.

[0077] The present invention has good economic benefits:

[0078] If the temporary support adopts the traditional scaffolding support method, the material cost, rental fee and labor cost are as follows:

[0079] Material rental fee: 50.7 (material usage / ton) × 3.0 (rental fee per ton per day) × 30 (number of days used) × 3 (three layers of material preparation) = 5589 yuan;

[0080] Material exit freight: 50.7 (material usage) × 150 (unit price) = 7605 yuan;

[0081] Labor cost: 10 (number of people for erection and dismantling of each floor) × 400 (unit price) × 29 (number of floors) = 116,000 yuan;

[0082] Other safety measures fee: 10,000 yuan;

[0083] Total cost: 5589+7605+116000+10000=139,200 yuan;

[0084] If the method of free top support for ultra-high space large-span truss floor deck of the present invention is adopted, the materials of the legs and the hanger rods can be directly obtained on site without incurring any cost. The design is simple to operate and the labor cost is negligible. The rental fee of the suspension beam is as follows:

[0085] Material rental fee: 440 (material consumption / meter) × 0.15 (rental fee per meter per day) × 7 (number of days used) = 462 yuan; the present invention can save costs of 138,700 yuan, with significant economic benefits, and has reference and learning value for similar engineering construction.

[0086] The top-support-free construction design of the ultra-high space large-span truss floor deck of the present invention has the characteristics of wide applicability, convenient construction, and safe operation. In terms of progress: it improves the construction efficiency and can achieve the construction node targets more quickly within a limited construction period; in terms of construction: it streamlines the construction process, solves the difficult problem of setting up temporary support frames in ultra-high spaces, breaks through the limitation of being unable to set up temporary support frames due to the small site, and greatly improves operational safety; in terms of resources and environmental protection: it realizes waste utilization, and most of the materials used in this design and construction are waste materials vacated on site, turning waste into treasure and saving resources.

[0087] The support and suspension system of the present invention is compact and light, and the construction is basically not limited by the site space, and has a wide range of applicability. The number of component types is small, and the on-site installation and disassembly speed is fast. The application of this design not only saves the rental fee of the scaffolding, the labor cost of erecting the frame, reduces the overall cost, but also greatly improves the construction efficiency.

[0088] The floor decking of the present invention plays a certain protective role, thereby avoiding the safety risks brought by high-altitude operations and eliminating the safety hazards caused by setting up a large number of temporary support frames.

[0089] The present invention is applicable to public construction projects with requirements for top-free support construction of ultra-high space and large-span reinforced truss floor decks, as well as similar projects with limited on-site space and tight construction period that make it inconvenient to set up a support system.

[0090] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0091] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for constructing super-high space large-span truss floor deck without top support, characterized in that: The following steps are involved: S1. Layout the floor decking according to the design requirements and specifications, and define the temporary support area; lay the floor decking on site according to the layout drawing; S2. Analyze the temporary support area in combination with the building structure and on-site working conditions; use the method of hanging the floor slab under the reverse support cantilever beam to resist the deformation, deflection and instability of the floor slab caused by the large span; S3. Design the system and layout of the suspended floor deck under the inverted cantilever beam. The system at least includes cantilever beams, outriggers, and hangers, forming a force transmission path from the floor deck, hangers, cantilever beams, outriggers to the structural steel beams; determine the material consumption according to the design scheme, and carry out cutting and processing; S4. Determine the plane position of the cantilever beam and the height of the outriggers by on-site layout according to the design plan; then fix the outriggers to the cantilever beam and hoist the cantilever beam to the construction floor for precise layout; S5. After the suspension beam is accurately arranged, connect the hanger rod with the suspension beam and the upper chord steel bars of the floor deck; S6. Concrete pouring and curing; S7. When the concrete strength reaches 75%, cut the hanger rod and remove the cantilever beam.

2. The method for constructing super-high space large-span truss floor deck without top support according to claim 1 is characterized in that: In S4, cantilever beams are arranged in the middle of the span of the floor deck.

3. The method for constructing super-high space large-span truss floor deck without top support according to claim 1, characterized in that: In S4, the suspension beam is first placed on the ground, and after the legs on both sides are fully welded to the lower flange of the suspension beam, the suspension beam is flipped 180° and erected, and then the joints between the legs and the upper flange of the suspension beam are fully welded. The height and width of the weld shall not be less than 5mm and 10mm respectively.

4. The method for constructing super-high space large-span truss floor deck without top support according to claim 3 is characterized in that: After the outriggers are welded, the cantilever beam with outriggers will be hoisted to the construction floor, precisely arranged according to the measured points, and the bottom of the outriggers will be spot welded to the structural steel beam.

5. The method for constructing super-high space large-span truss floor deck without top support according to claim 1, characterized in that: After the cantilever beams are arranged and fixed in S5, the cantilever beams are connected to the floor decking plates. Each hanger rod is arranged in the middle of a single floor decking plate and arranged at equal intervals.

6. The method for constructing super-high space large-span truss floor deck without top support according to claim 5, characterized in that: When the hanger is installed, it is arranged opposite and staggered relative to the center line of the suspension beam. The upper part of the hanger is welded and fixed to the upper flange and lower flange of the suspension beam, and the lower part of the hanger is welded and connected to the upper chord steel bars and steel plates of the floor decking.

7. The method for constructing super-high space large-span truss floor deck without top support according to any one of claims 1 to 6, characterized in that: Before pouring concrete in S6, the connection quality of the cantilever beams, legs and hangers, as well as the position of the cantilever beams and the spacing between the hangers should be inspected and accepted. Concrete pouring can only be carried out after passing the inspection and acceptance. The pouring method adopts continuous pouring starting from one end and gradually withdrawing the pipe. During pouring, a flat vibrator and a vibrating rod are used in conjunction with each other. At the end of pouring, a line is pulled through to control the concrete elevation of the floor slab. After the surface is finished, maintenance should be carried out in a timely manner, and the maintenance time should be no less than 7 days.

8. The method for constructing super-high space large-span truss floor deck without top support according to any one of claims 1 to 6, characterized in that: When cutting the hanger in S7, the cut is made along the structural elevation of the floor slab to ensure that the cross section of the hanger is not higher than the structural elevation of the floor slab after the cut is completed.

9. The super-high space large-span truss floor deck construction free-top support structure is characterized by: include: A cantilever beam (1) is arranged in the middle of the span of the floor deck (4) in the temporary support area; At least two groups of legs (2) are fixed to the two ends of the cantilever beam (1), and the bottom of each leg (2) is fixed to the structural steel beam (5); A plurality of hangers (3) are arranged staggered along both sides of the suspension beam (1), and the hangers (3) arranged opposite to each other on both sides are arranged at equal intervals. The top of each hanger (3) is fixed to the upper flange (11) and the lower flange (12) of the suspension beam (1), and the bottom thereof is connected to the upper chord steel bars and steel plates of the floor decking (4).

Images