Construction method of cantilever construction operation platform

Abstract

The invention discloses a construction method of a cantilever construction operation platform. The method includes the following steps that firstly, a sample is obtained, bailey trusses are assembled on the ground, then the Bailey trusses are assembled into Bailey beams, the Bailey beams are hoisted, longitudinal distribution beams and transverse distribution beams are installed after the Bailey beams are installed, disc buckle supporting frames are installed on the Bailey beams, beam and slab formworks are installed through the disc buckle supporting frames, steel bar construction is conducted while the beam and slab formworks are installed, and the beam and slab formworks are constructed. And after the inner concrete pouring and tamping-concrete curing is completed, dismantling is conducted according to the sequence of the beam plate formworks, the disc buckle supporting frames, the distribution beams and the bailey beams. The problems of low efficiency and poor stability in traditional construction are solved through modular bailey beam design, BIM dynamic analysis, quick erection of a disc buckle supporting frame and a concrete layered pouring process. The construction safety and economical efficiency are remarkably improved, and the method is suitable for various complex cantilever structure projects.

Description

Technical Field

[0001] The invention relates to a construction method of a cantilever construction work platform. Background Art

[0002] As a key temporary structure in high-rise buildings, bridges and other projects, the safety and construction efficiency of cantilevered construction platforms directly affect the project progress and cost. Traditional cantilevered platforms mostly use ordinary steel sections or simple truss structures, which have the following problems: First, the structural stability is insufficient. Traditional platforms mostly rely on non-standard components for assembly, and the node connection method is single, such as welding or bolting, which can easily lead to local stress concentration, insufficient overall rigidity, and difficulty in adapting to complex load conditions. Second, the construction efficiency is low, the assembly process is cumbersome, and the hoisting relies on manual adjustment, which takes a long time. The assembly of ordinary Bailey beams requires the collaboration of many people, and there is a lack of a systematic hoisting plan, which can easily lead to safety risks. Third, the material utilization rate is low. In traditional designs, the dimensions of components such as support frames and distribution beams are fixed, which makes it difficult to flexibly adapt to different span requirements, resulting in material waste. Fourth, quality control is difficult, the template installation accuracy is insufficient, and the concrete pouring process lacks standardized processes, which is prone to defects such as cracks and leakage. Summary of the Invention

[0003] In response to the shortcomings of the existing technology, the present invention provides a construction method for a cantilever construction work platform, which solves the problems of poor structural stability, low construction efficiency, material waste and insufficient quality control in the existing technology, and realizes the full optimization of modular design, precise lifting, rapid support erection and concrete pouring.

[0004] In order to solve the above technical problems, the present invention is solved by the following technical solutions: A construction method of a cantilever construction work platform, which is characterized by comprising the following steps: Step A: assembling the Bailey frame on the ground, the Bailey plates in the Bailey frame are in a straight line, and the Bailey plates are connected by connecting plates; Step B: then splicing the Bailey frame into a Bailey beam, connecting the Bailey frame through a truss, and fixing the truss and the Bailey frame through a pin shaft; Step C: lifting the Bailey beam and then installing the Bailey beam on the main body; Step D: after the Bailey beam is installed, the longitudinal distribution beam and the transverse distribution beam are installed, and the Bailey beam, the longitudinal distribution beam and the transverse distribution beam are connected and fixed by U-shaped clamps; Step E: installing a buckle support frame on the Bailey beam; Step F: installing the beam and slab formwork through the buckle support frame; Step G: carrying out steel bar construction while installing the beam and slab formwork; Step H: pouring concrete in the beam and slab formwork; Step I: after the concrete is cured, it is removed in the order of the beam and slab formwork, the buckle support frame, the distribution beam, and the Bailey beam.

[0005] In the above technical solution, preferably, before step A, BIM modeling is performed according to the actual plan of the cantilever construction work platform, and finite element analysis is performed.

[0006] In the above technical solution, preferably, in step A, the Bailey frame is composed of two Bailey plates and two 90 support frames.

[0007] In the above technical solution, preferably, in step B, each Bailey beam includes 5 groups of Bailey frames, and the trusses are welded by upper and lower chords, vertical rods and diagonal braces.

[0008] In the above technical solution, preferably, in step C, before hoisting, the site should be leveled, and the Bailey beam pieces and installation positions should be determined according to the Bailey beam hoisting method requirements.

[0009] In the above technical solution, preferably, in step F, the installation of the beam and slab formwork includes the following steps: the slab formwork is laid with pine wood squares on the bottom of the plywood, the specification of the square wood at the bottom of the board is 50×70mm, and the spacing between the wood squares is set at 300mm according to the thickness of the floor slab; the secondary square wood ribs are placed on the main steel pipe ribs, and when laying the board joints, the board joints should be tight to prevent leakage of mortar; after the platform board is laid, the template elevation is checked with a spirit level.

[0010] In the above technical solution, preferably, in step F, before pouring the cantilever structure concrete, the column concrete should be poured first. After the column concrete strength reaches more than 75% of the design value, the beam should be poured. The concrete is vibrated with an inserted vibrator, from the indoor non-cantilever structure floor to the outdoor cantilever structure floor, and the cantilever section is poured from the root to the end.

[0011] The proposed cantilever construction platform construction method demonstrates significant advantages in both technical features and effectiveness. Technically, this method achieves standardized construction through a modular Bailey beam design. During Bailey beam assembly, ground-based pre-assembly and tower crane hoisting are integrated, enabling a 15-meter Bailey beam assembly to be hoisted into place in a single operation using a tower crane, significantly reducing manual adjustment time. Furthermore, a parametric 3D model is constructed using BIM technology, material properties are correlated, and finite element analysis is performed to simulate stress distribution under construction loads, wind loads, and concrete impact. This optimizes support frame spacing and U-hoop placement, and generates hoisting path animations using collision detection to mitigate construction interference risks. The installation of the buckle support frame utilizes a standardized six-step process, including base positioning, pedestal installation, layered installation of horizontal and vertical rods, and pre-arching. Real-time calibration is performed using a laser level to ensure support system stability. The concrete pouring process emphasizes layered control and refined vibration operations, implementing a comprehensive layered slurry rushing method from the root to the end. Strain sensors are used to monitor formwork displacement in real time, and emergency reinforcement is initiated when the time exceeds the limit, forming a dynamic quality control closed loop. In addition, the template system construction strictly regulates the spacing between wooden planks, joint treatment and material standards, and the steel pipe fasteners are free of cracks and thread slippage, ensuring construction accuracy from the source.

[0012] Compared with the existing technology, the method of this application has achieved multi-dimensional performance improvement through technology integration and process innovation. First, the structural safety is significantly enhanced, and the risk of local stress concentration is effectively avoided; secondly, the construction efficiency is greatly optimized, the overall platform erection efficiency is improved, and in terms of material costs, standardized design combined with BIM optimization reduces engineering usage, with significant economic benefits. This method can be flexibly adapted to different engineering scenarios, combines BIM to generate special-shaped distribution beam parameters, and uses flexible templates to achieve precise adaptation of curved surfaces, thus achieving wide applicability of the process. In summary, the present invention systematically solves the core problems of insufficient structural stability, low efficiency, material waste, and large quality fluctuations in the construction of traditional cantilever platforms through technology integration and process innovation, providing an efficient, safe, and economical solution for complex cantilever projects, with significant engineering application value and promotion potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the truss unit and truss pin of this application.

[0014] Figure 2 This is the main view of the cantilever construction work platform of this application.

[0015] Figure 3 It is a side view of the cantilever construction work platform of this application. DETAILED DESCRIPTION

[0016] Example 1, as Figures 1 to 3 As shown: A construction method for a cantilever construction work platform includes the following steps: BIM modeling is performed according to the actual plan of the cantilever construction work platform, and finite element analysis is performed to ensure that the designed cantilever construction work platform is safe and stable.

[0017] The Bailey frame uses 321 type Bailey plates. A single Bailey frame is composed of 2 Bailey plates and 2 90 support frames. Each Bailey beam has a total of 5 frames.

[0018] The Bailey beam is composed of truss units, truss pins, end columns, truss bolts, chord bolts, etc.

[0019] A truss unit consists of truss plates and truss pins. Truss plates are welded together from upper and lower chords, vertical bars, and diagonal braces. The upper and lower chords have female ends and male ends, each with a pin hole. To connect two truss sections, insert the male end of one section into the female end of the other, align the pin holes, and insert the pins. The truss holes are used as follows: Chord bolt holes are used to connect double-layer or reinforced Bailey beams. Truss bolts or chord bolts are inserted into the chord bolt holes to connect the double-layer truss or truss to the reinforced chord. Support frame holes are used to install support frames. When the truss is used as a main beam, the two center holes are used, while when it is used as a bridge foot, the two end holes are used to strengthen the connection between the two rows of trusses. Wind brace holes are used to connect wind-resistant braces. Support frame holes on the end vertical bars are used to install support frames, diagonal braces, and connecting plates. Crossbeam clamp holes are used to install crossbeam clamps. The lower chord is equipped with four crossbeam pads with pegs to define the crossbeam's position. Each truss weighs 265 kg; four people are required to lift it by shoulder, while eight people are required to lift it by hand. If the reinforcing chords of the upper and lower chords are connected and then lifted by hand, an additional four people are required.

[0020] Truss pins are used to connect trusses. There's a small circular hole at one end of the pin for inserting a safety card during installation to prevent the pin from falling out. The pin's top has a groove aligned with the small circular hole. During installation, keep the groove parallel to the upper and lower chords to ensure the safety card fits smoothly into the pin hole.

[0021] The Bailey beam is assembled using double-row, single-layer, unreinforced Bailey frames. The beam is assembled on the ground and hoisted as a whole. The individual Bailey frames are installed in a straight line. Two people use wooden sticks through the gusset plate to fine-tune the Bailey beam. After aligning the lower chord pin holes, the pin is inserted. The rear end of the Bailey beam is then lifted, the upper chord pin inserted, and the safety latch engaged. Bailey beams are assembled in groups, one at a time, in two horizontal rows. Each Bailey frame is 15 meters long. The Bailey pieces are connected with connectors. After assembly, a tower crane is used for lifting.

[0022] A standard Bailey beam truss segment is 3m long, 1.5m high, and weighs 270kg. When hoisting a Bailey beam, pay attention to its stability. A single Bailey beam unit consists of two Bailey plates and two 90° support frames, connected by matching pins. Before each hoisting operation, inspect the hoisting hook and wire rope for potential safety hazards and replace them immediately if any are found. The hoisting hook is a dedicated hook and should not be replaced at will.

[0023] The QTZ160 (XGT6515A-10S) tower crane was used for the hoisting. Prior to installation, the site was leveled. The Bailey beam segments and installation positions were determined according to Bailey beam hoisting procedures, aiming for the safest, fastest, and smallest possible slewing radius. Before installation, the Bailey beam segments and dimensional deviations were checked against the drawings, and any identified issues were promptly corrected. The position of embedded components was measured on-site to ensure compliance. To ensure the construction schedule, a reasonable crew was assigned to the hoisting team: one commander, three riggers, one safety officer, and two signalmen. The number of personnel for these roles was adjusted based on the actual on-site hoisting situation.

[0024] After the Bailey main beam is installed, the longitudinal and transverse steel distribution beams are installed. The distribution beams are installed strictly according to the design plan, and the distribution beams are connected to the Bailey beams and between the distribution beams with U-shaped clamps.

[0025] The installation of the truss brackets shall be strictly in accordance with the attached drawings. The beam span shall be pre-arched to ≮4‰. The specifications and spacing of each support and wooden slat shall be constructed in accordance with the plan requirements.

[0026] Installation of beam and slab formwork. For this project, the platform formwork utilizes plywood laid with pine timbers underneath. The timbers at the bottom of the planks are 50 x 70 mm, and the spacing between the timbers is set at 300 mm, depending on the thickness of the floor slab. The secondary timbers are placed on the primary steel pipes. When laying the planks, the joints should be tight to prevent grout leakage. After the platform planks are laid, the formwork elevation should be checked with a level, and any problems should be corrected promptly.

[0027] Formwork quality requirements: Requirements for wooden formwork and its supporting materials: The material selection standard for wood load-bearing structures should not be lower than grade III. Steel should comply with the Q235 steel standard in the "Ordinary Carbon Steel Grades and General Technical Conditions" (GB700-79). Severe defects such as knots and gaps on the wood should be cut off. Steel pipes with serious rust spots, bending deformations, and fractures cannot be used upon arrival. Steel pipe fasteners must be intact, without cracks, thread slippage, etc. The formwork and its supports must have sufficient strength, rigidity and stability; its supporting parts should have sufficient supporting area. The surface of the formwork is flat, the joints are tight, and there is no leakage. The measured allowable deviation of the formwork is strictly controlled to have a pass rate of more than 90%.

[0028] Concrete construction method. Before pouring, check whether the elevation and position of the formwork and the cross-sectional dimensions of the components are consistent with the design; whether the installed support system is stable and whether the support and formwork are reliably fixed; the tightness of the formwork; the specifications, quantity, installation position and component joint connection welds of the steel bars and embedded parts are consistent with the design. Before pouring concrete, the garbage, wood chips, shavings, sawdust, soil in the formwork and the oil stains, iron sheets and other debris on the steel bars should be flushed out through the cleaning holes or blown out with an air compressor. The formwork should be moistened with water, but no water should be left. After it is moistened, the gaps in the wooden formwork that have not yet been sealed should be sealed to prevent leakage. Pouring requirements: Before pouring the concrete of the cantilever structure, the column concrete should be poured first. After the column concrete strength reaches more than 75% of the design value, the beams and slabs should be poured. The concrete should be vibrated with an inserted vibrator. The cantilever section should be poured from the base to the end, starting from the indoor non-cantilever structure floor slab to the outdoor cantilever structure floor slab.

[0029] During the pouring process, control the uniformity and density of the concrete. Once the concrete mix arrives at the pouring site, it should be immediately placed in the mold. Any significant changes in the uniformity or consistency of the concrete mix during the pouring process should be addressed promptly. Concrete pouring should be carried out in sections and layers. The pouring height should be determined based on a comprehensive consideration of the concrete supply capacity, the volume poured at a time, the initial setting time of the concrete, the structural characteristics, and the density of the reinforcement. It is generally 1.25 times the length of the vibrator's active portion. During the pouring process, inspect the formwork, reinforcement, pre-set holes, and embedded parts for movement, deformation, or blockage. Any problems should be addressed immediately and repaired before the poured concrete begins to set. After vibrating, use a long aluminum alloy scraper to level the concrete using the elevation line. Then, use a wooden trowel to carefully level and press the concrete two to three times. (Use the trowel to carefully level and press the concrete at construction joints, pre-set holes, embedded parts, and along the sides of the wall.) The final pass of trowel leveling should be completed while the concrete is absorbing water. During vibrating, the duration of each vibration point should be based on the surface slurry. To ensure the upper and lower layers of concrete are integrated, the vibrator should be inserted 5-10 cm into the lower concrete layer. When vibrating, pay attention to areas with dense rebar and openings. To prevent missed vibrations, vibrate simultaneously on both sides of the opening, and ensure that the height of the concrete is roughly the same. Walking on and working on the poured concrete is strictly prohibited until the concrete strength reaches 1.2 MPa. During the concrete pour, a dedicated person should monitor the working status of the formwork support system. Any abnormalities detected by the observer should be promptly reported to the construction manager, who should immediately notify the pouring personnel to suspend operations. In case of emergency, emergency measures should be implemented to quickly evacuate personnel and implement reinforcement. Concrete pouring is carried out using a comprehensive layered slurry rush method, with each layer poured to a thickness of 300 mm. When the lower layer of concrete has not yet set, the second layer is poured, and this process is repeated layer by layer until the pour is complete. Insert the vibrator quickly and withdraw slowly, vibrating each point for approximately 20-30 seconds. Ensure the concrete surface no longer sinks noticeably, bubbles appear, and the slurry overflows. For layered areas, insert the vibrator approximately 5-10 mm into the lower layer to eliminate the joint between the two layers. Additionally, ensure the bottom of the side wall is vibrated securely, and avoid disturbing rebar or embedded components during vibration.

[0030] After the concrete is cured, it will be dismantled in the order of beam and slab formwork, disc support frame, distribution beam and Bailey beam.

Claims

1. A construction method for a cantilevered construction work platform, characterized by: The following steps are involved: Step A: Assemble the Bailey frame on the ground. The Bailey pieces in the Bailey frame should be in a straight line and connected with connecting pieces. Step B: Then, the Bailey frames are assembled into Bailey beams, and the Bailey frames are connected by trusses, and the trusses and Bailey frames are fixed by pins; Step C: Lift the Bailey beam and then install it on the main body; Step D: After the Bailey beam is installed, the longitudinal distribution beam and the transverse distribution beam are installed. The Bailey beam, the longitudinal distribution beam and the transverse distribution beam are connected and fixed by U-shaped clamps; Step E: Install the buckle support frame on the Bailey beam; Step F: Install the beam and slab formwork using the buckle support frame; Step G: Install the beam and slab formwork while carrying out reinforcement construction; Step H: pouring concrete in beam and slab formwork; Step I: After the concrete is cured, dismantle it in the order of beam and slab formwork, disc support frame, distribution beam and Bailey beam.

2. The construction method of a cantilever construction work platform according to claim 1, characterized in that: In step A, the Bailey frame is composed of two Bailey plates and two 90 support frames.

3. The construction method of a cantilever construction work platform according to claim 2, characterized in that: In step B, each Bailey beam includes five sets of Bailey frames, and the trusses are welded together by upper and lower chords, vertical rods and diagonal braces.

4. The construction method of a cantilever construction work platform according to claim 1, wherein In step C, before hoisting, the site must be leveled and the Bailey beam pieces and installation positions must be determined according to the Bailey beam hoisting method requirements.

5. The construction method of a cantilever construction work platform according to claim 1, characterized in that: In step F, the installation of the beam and slab formwork includes the following steps: the slab formwork is laid with pine wood squares on the bottom of the plywood. The specifications of the square wood at the bottom of the board are 50×70mm, and the spacing of the wood squares is set at 300mm according to the thickness of the floor slab; the secondary square wood ribs are placed on the main steel pipe ribs. When laying the board joints, the board joints should be tight to prevent leakage of mortar; after the platform board is laid, the formwork elevation is checked with a spirit level.

6. The construction method of a cantilever construction work platform according to claim 1, characterized in that In step F, before pouring the cantilever structure concrete, the column concrete should be poured first. After the column concrete strength reaches more than 75% of the design value, the beam should be poured. The concrete is vibrated with an inserted vibrator, starting from the indoor non-cantilever structure floor to the outdoor cantilever structure floor, and the cantilever section is poured from the root to the end.

7. The construction method of a cantilever construction work platform according to claim 1, characterized in that: Before step A, BIM modeling and finite element analysis were carried out according to the actual plan of the cantilever construction platform.

Images