Construction technology of bottom mould floor support plate suitable for steel and concrete composite beam cast-in-situ bridge deck construction

Abstract

The application discloses a bottom mould floor support plate construction technology suitable for steel-concrete composite beam cast-in-situ bridge deck plate construction and belongs to the field of cast-in-situ concrete component form construction, which can solve the problems of difficult installation of the bottom mould of the steel-concrete composite beam cast-in-situ bridge deck plate, large waste of building materials, cost increase and slow construction period. According to the size of the floor support plate, the application performs line laying at a reinforcing position of the top plate of the steel beam, performs installation and connection, straightens, flattens, connects and fixes the arranged floor support plate. The connection between the floor support plates is reinforced by adding fillet welding. The two sides of the steel-concrete composite beam are each provided with a 70cm cantilever arm, and the concrete thickness is 20cm. The cantilever arm part of the side beam is constructed by using a hanging form method, a steel cantilever beam is arranged on the top of the steel beam to hang up the steel bar truss floor support plate bottom mould. After the floor support plate is paved, the steel bars are bound, and the bridge deck plate is poured. The steel bar truss floor support plate satisfies various loads such as structure and construction, can avoid construction procedures such as formwork erection, formwork removal, support system erection and removal and the like, and improves construction operation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of formwork construction for cast-in-place concrete components, and specifically relates to a bottom formwork floor deck construction process suitable for cast-in-place bridge deck construction of steel-concrete composite beams. Background Technology

[0002] With the rapid development of urban construction and the continuous expansion of transportation facilities in my country, more and more elevated roads crossing existing roads are adopting large-span steel-concrete composite beam structures that are easy to construct. Currently, the traditional construction process for reinforced concrete structures of steel-concrete composite beam bridge decks involves erecting formwork support frames, laying formwork, tying reinforcing bars, and pouring concrete. The formwork and support frames are only removed after the concrete reaches the structural requirements. This construction process is cumbersome, requiring significant labor, tools, and management effort for erecting support frames and formwork, and posing considerable safety hazards. Non-standard or unregulated worker practices can lead to quality defects and accidents. Furthermore, formwork typically suffers significant wear and tear, hindering cost control. Therefore, developing a new construction technology that shortens the formwork installation and reinforcement cycle, increases construction productivity, and reduces the number of workers and machinery required is crucial for resource conservation, cost reduction, and construction safety. Summary of the Invention

[0003] This invention addresses the problems of difficult installation of bottom formwork for cast-in-place steel-concrete composite beam bridge decks, resulting in significant waste of building materials, increased costs, and slow construction cycles. It provides a bottom formwork floor slab construction process suitable for cast-in-place steel-concrete composite beam bridge deck construction, replacing the traditional method of erecting formwork support frames for reinforced concrete structures of steel-concrete composite beam bridge decks.

[0004] The present invention adopts the following technical solution:

[0005] A construction process for the bottom formwork floor deck of a steel-concrete composite beam cast-in-place bridge includes the following steps:

[0006] The first step is on-site inspection.

[0007] When the steel truss floor decking arrives on site, it should be placed directly at the installation location. During packaging, avoid misalignment to prevent the profiled steel sheets from being moved manually over long distances during installation. At the same time, all accessories for the steel truss floor decking, such as baffles and edge trims, should be delivered to the site in advance.

[0008] The second step is the laying of the steel truss floor slab.

[0009] (1) Based on the dimensions of the steel truss floor deck, mark the reinforcement positions on the top plate of the steel beam, and then install and weld them;

[0010] (2) Before laying the steel truss floor deck, the debris on the top surface of the steel beam must be cleaned first, and any bent or twisted steel truss floor deck must be corrected. The gap between the steel truss floor deck and the top surface of the steel beam should be controlled to be less than 1 mm.

[0011] (3) After cleaning the top surface of the steel beam and confirming that there is no paint on the steel beam, mark the laying position of each steel truss floor deck slab on the steel beam according to the layout diagram, configure the required number of slabs according to their different slab types, arrange them along the ink lines, and then cut the slabs.

[0012] (4) Straighten, flatten, and weld the arranged steel truss floor decks. The connection between the floor decks is reinforced with fillet welds to prevent the floor decks from moving or separating. The weld spacing is 300mm and the length is 20-30mm.

[0013] (5) Use a stud welding machine to penetrate the profiled steel sheet and weld it together with the steel beam to anchor the floor deck to the steel beam;

[0014] The third step is to reinforce the steel beam cantilever floor deck.

[0015] The steel-concrete composite beam has 70cm cantilever arms on both sides of the beam edge, and the concrete thickness is 20cm. The cantilever arm part of the edge beam is constructed using the suspended formwork method, in which a steel cantilever beam is set on the top of the steel beam to lift the bottom formwork of the steel truss floor slab.

[0016] Furthermore, the suspended formwork construction method includes the following steps: 16# I-beams are arranged transversely on the side beams as cantilever beams. Tie rods are installed at the cantilever ends and welded to the lower chord reinforcement of the steel truss floor slab bottom formwork. Two rows of seamless steel pipes are installed on the top surface of the 16# I-beams at the upper part of the cast-in-place section, and butterfly buckles with double nuts are used for adjustment and fixation. Two φ16 steel bars are welded to the inner top plate of the steel beam at the fixed end as I-beam steel supports. A φ16 steel bar is welded to the outer top plate of the steel beam as a temporary support. The steel bars are fully welded to the top surface of the steel beam and the I-beams. The 16# I-beams are welded and fixed to the steel supports, 15cm higher than the cast-in-place bridge deck.

[0017] The fourth step is to tie the reinforcing steel truss floor slab after it is laid, and then pour the bridge deck.

[0018] Furthermore, the I-beams are 4m long and spaced 2m apart.

[0019] Furthermore, the seamless steel pipe has a diameter of 48mm and a wall thickness of 3.5mm.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. This invention uses steel truss floor decking, which features simple and quick construction, shortened construction period; it replaces traditional formwork and improves upon the shortcomings of traditional formwork; it can be used as part of the structural strength, reducing material costs; it is easy to install reinforcement, wiring, and piping; it has a neat and beautiful appearance; it is lightweight, high-strength, has a large load-bearing capacity, and good seismic resistance.

[0022] 2. As part of the permanent structure of the steel-concrete beam bridge deck, the specifications and layout of the TDA3-90 type steel truss floor deck were determined through structural calculations and detailed design, eliminating the need for support frame erection and formwork laying. Since the TDA3-90 type deck includes its own floor slab reinforcement, only the upper bridge deck reinforcement needs to be laid on-site before pouring concrete, reducing costs, significantly improving work efficiency, and minimizing safety and quality risks.

[0023] 3. Steel truss floor slabs can withstand various structural and construction loads, eliminating the need for formwork erection, formwork removal, and support system installation and dismantling, significantly reducing the workload, improving construction efficiency, and accelerating construction progress. It also enhances operational safety, generates less waste and noise during construction, and promotes environmentally friendly and green construction practices.

[0024] 4. Currently, most cast-in-place bridge decks for steel-concrete composite beams are constructed using the scaffolding formwork method, which requires the erection and dismantling of scaffolding and formwork. However, the use of steel truss floor decks eliminates the need for scaffolding erection and dismantling, saving a significant amount of manpower and resources and improving construction progress. Therefore, the research on this technology can greatly reduce project costs and has good economic benefits.

[0025] 5. Floor decking is a metallic material with strong fire resistance and corrosion resistance, and excellent environmental performance. Construction is simple, effectively increasing the working space for personnel and reducing safety hazards. At the same time, this construction method reduces noise and dust, and decreases labor input by reducing work steps, resulting in significant social benefits. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the cantilever suspension support device of the present invention;

[0027] Figure 2 This is a schematic diagram of the steel truss floor deck structure of the present invention;

[0028] Among them: 1-cantilever; 2-steel-concrete composite beam; 3-steel truss floor deck; 4-tie rod; 5-seamless steel pipe; 6-steel support; 7-galvanized steel plate; 8-web member; 9-upper chord reinforcement; 10-lower chord reinforcement; 11-temporary steel support. Detailed Implementation

[0029] The invention will be further described with reference to the accompanying drawings.

[0030] This invention addresses the problems of difficult installation of bottom formwork for cast-in-place steel-concrete composite beam bridge decks, resulting in significant waste of building materials, increased costs, and slow construction cycles. It provides a bottom formwork floor slab construction process suitable for cast-in-place steel-concrete composite beam bridge deck construction, replacing the traditional process of erecting formwork support frames for reinforced concrete structures of steel-concrete composite beam bridge decks.

[0031] The present invention adopts the following technical solution:

[0032] TDA3-90 type steel truss floor decking; based on the floor decking dimensions, the reinforcement positions are marked on the top of the steel beam, then installed, connected, straightened, flattened, and fixed. Fillet welds can be used to reinforce the connections between floor deckings to prevent them from moving or separating; the weld spacing should be approximately 300mm, and the length 20-30mm is recommended. The steel-concrete composite beam has 70cm cantilever arms on both sides, with a 20cm thick concrete layer. For the cantilever arms of the edge beams, a suspended formwork method is used, where a steel cantilever beam is set on top of the steel beam to lift the bottom formwork of the steel truss floor decking. After the floor decking is laid, the reinforcing bars are tied, and the bridge deck is poured.

[0033] The specific construction process is as follows:

[0034] 1. On-site inspection

[0035] The acceptance inspection and construction shall be carried out in strict accordance with the design and the "Code for Acceptance of Construction of Steel Structures" GB50205-2001.

[0036] (1) The steel truss floor decking should be delivered to the site in strict accordance with the plan. Due to the narrow site area and insufficient space for stacking, it should be placed directly at the installation location upon arrival. When packing, avoid misalignment to prevent the profiled steel sheets from being moved manually over long distances during installation. At the same time, all accessories such as baffles and edge trims of the floor decking should be delivered to the site in advance.

[0037] (2) The raw materials of the steel truss floor deck are inspected for their variety and specifications, and some accessories, such as edge trims, baffles, supports, etc., are inspected for their quality certificates and inspection reports.

[0038] (3) This project uses TDA3-90 type steel truss floor decking. The floor decking is made of 0.5mm galvanized steel sheet, and the top chord, web members, and bottom chord members are made of steel bars with diameters of 10mm, 4.5mm, and 8mm, respectively. See the table below for details (Table 600mm wide for Type A steel truss floor decking selection):

[0039]

[0040] 2. Laying of reinforced steel truss floor decking

[0041] (1) Based on the dimensions of the floor deck, mark the reinforcement positions on the top plate of the steel beam, and then install and weld.

[0042] (2) Before laying the floor decking, the debris on the top surface of the steel beam must be cleaned first, and the floor decking that is bent or twisted should be corrected. The gap between the decking and the top surface of the steel beam should be controlled to be less than 1mm.

[0043] (3) After cleaning the top surface of the steel beam and confirming that there is no paint on the steel beam, mark the laying position of each floor decking on the steel beam with ink lines according to the layout diagram, configure the required number of boards according to their different board types, arrange them along the ink lines, and then cut the edges.

[0044] (4) Straighten, flatten, and weld the arranged floor decking. The connection between the floor decking can be reinforced with fillet welds to prevent the floor decking from moving or separating. The weld spacing should be about 300mm and the length should be 20-30mm.

[0045] (5) Use a stud welding machine to penetrate the profiled steel sheet and weld it together with the steel beam to anchor the floor deck to the steel beam.

[0046] 3. Reinforcement of steel beam cantilever floor decking

[0047] The steel-concrete composite beam has 70cm cantilever arms on both sides of its edge, with a 20cm thick concrete layer. For the cantilever sections of the edge beams, a suspended formwork method is used. A steel cantilever beam is installed on top of the steel beam to lift the bottom formwork of the steel truss floor slab. Figure 1 As shown, the suspended floor slab bottom formwork method was adopted for construction. Specifically, 16# I-beams (4m long, 2m spacing) were arranged transversely on the side beams as cantilever beams. Tie rods were welded to the lower chord reinforcement of the steel truss floor slab bottom formwork at the cantilever ends. Two rows of seamless steel pipes (48mm diameter, 3.5mm wall thickness) were placed side-by-side on the top surface of the 16# I-beams at the upper part of the cast-in-place section, and fixed using butterfly buckles with double nuts for adjustment. Two φ16 steel bars were welded to the inner top plate of the steel beam as steel supports for the I-beams, and one φ16 steel bar was welded to the outer top plate of the steel beam as a temporary support. The steel bars were fully welded to the top surface of the steel beam and the I-beams. The 16# I-beams were welded and fixed to the steel supports, 15cm above the cast-in-place bridge deck.

Claims

1. A construction process for the bottom formwork floor deck slab adapted to the construction of cast-in-place bridge decks of steel-concrete composite beams, characterized in that: Includes the following steps: The first step is on-site inspection. When the steel truss floor decking arrives on site, it should be placed directly at the installation location. During packaging, avoid misalignment to prevent the profiled steel sheets from being moved manually over long distances during installation. At the same time, all accessories for the steel truss floor decking, such as baffles and edge trims, should be delivered to the site in advance. The second step is the laying of the steel truss floor slab. (1) Based on the dimensions of the steel truss floor deck, mark the reinforcement positions on the top plate of the steel beam, and then install and weld them; (2) Before laying the steel truss floor deck, the debris on the top surface of the steel beam must be cleaned first, and any bent or twisted steel truss floor deck must be corrected. The gap between the steel truss floor deck and the top surface of the steel beam should be controlled to be less than 1 mm. (3) After cleaning the top surface of the steel beam and confirming that there is no paint on the steel beam, mark the laying position of each steel truss floor deck slab on the steel beam according to the layout diagram, configure the required number of slabs according to their different slab types, arrange them along the ink lines, and then cut the slabs. (4) Straighten, flatten, and weld the arranged steel truss floor decking. The connection between the floor deckings is reinforced with fillet welds. The weld spacing is 300mm and the length is 20-30mm. (5) Use a stud welding machine to penetrate the profiled steel sheet and weld it together with the steel beam to anchor the floor deck to the steel beam; The third step is to reinforce the steel beam cantilever floor deck. The steel-concrete composite beam has 70cm cantilever arms on both sides of the beam edge, and the concrete thickness is 20cm. The cantilever arm part of the edge beam is constructed using the suspended formwork method, in which a steel cantilever beam is set on the top of the steel beam to lift the bottom formwork of the steel truss floor slab. The suspended formwork construction method includes the following steps: 16# I-beams are arranged transversely on the side beams as cantilever beams. Tie rods are installed at the cantilever ends and welded to the lower chord reinforcement of the steel truss floor slab bottom formwork. Two rows of seamless steel pipes are installed on the top surface of the 16# I-beams at the upper part of the cast-in-place section, and butterfly buckles with double nuts are used for adjustment and fixation. Two φ16 steel bars are welded to the inner top plate of the steel beam as I-beam steel supports at the fixed end. A φ16 steel bar is welded to the outer top plate of the steel beam as a temporary support. The steel bars are fully welded to the top surface of the steel beam and the I-beams. The 16# I-beams are welded and fixed to the steel supports, 15cm higher than the cast-in-place bridge deck. The fourth step is to tie the reinforcing steel truss floor slab after it is laid, and then pour the bridge deck.

2. The bottom formwork floor slab construction process for cast-in-place bridge deck construction of steel-concrete composite beams according to claim 1, characterized in that: The I-beams are 4m long and spaced 2m apart.

3. The bottom formwork floor slab construction process for cast-in-place bridge deck construction of steel-concrete composite beams according to claim 1, characterized in that: The seamless steel pipe has a diameter of 48mm and a wall thickness of 3.5mm.

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