Support structure of fabricated laminated slab and construction method thereof

Abstract

The application discloses a supporting structure of a fabricated laminated slab and a construction method thereof, and comprises a plurality of horizontally arranged horizontal rods and vertically arranged vertical rods, wherein the horizontal rods comprise X-axis rods and Y-axis rods which are perpendicular to each other and form a three-axis system perpendicular to the vertical rods along a Z-axis; a component is arranged at the intersection of each node to connect the vertical rod and the horizontal rod; each vertical rod is provided with a top support which is adjustably connected to the top of the vertical rod; and each top support is connected with an adjacent top support through a horizontal rod. The top support and the component are used as the node connecting piece, the overall stability of the formwork supporting system is improved, the arrangement of the horizontal rods is reduced, the specifications of the supporting rods and the connecting pieces are unified on the basis of meeting the vertical bearing capacity and the overall stability, the number of the rods is reduced, the construction efficiency is improved, and the materials are saved while the construction quality is ensured.

Description

Technical Field

[0001] This invention belongs to the field of building construction technology, and in particular to a support structure used in prefabricated composite slabs, as well as a construction method for the support structure. Background Technology

[0002] Currently, prefabricated concrete structures are the main form of prefabricated construction in China, boasting advantages such as relatively low cost and wide applicability. They will continue to dominate the selection of prefabricated building structures in the future. Achieving the target proportion of prefabricated building area in new construction while gradually increasing the prefabrication rate will inevitably be a relatively long development process. Simultaneously, it is crucial to continuously promote the research and application of advanced and applicable technologies, processes, and equipment, scientifically and rationally organize construction, develop construction specialization, improve mechanization levels, and reduce heavy and complex manual labor and wet operations. The current support systems used on-site for prefabricated concrete structures are mainly traditional coupler-type steel pipe scaffolding, cup-lock steel pipe scaffolding, and socket-type steel pipe scaffolding. These systems suffer from problems such as large workload for support installation and dismantling, numerous horizontal and vertical intersecting members, narrow spaces between scaffold structures, high losses, and cumbersome elevation control. These issues no longer meet the needs of industrialized building development and even hinder the rapid development of prefabricated buildings.

[0003] The existing support structure for prefabricated composite slabs requires a certain number of horizontal bar layers at a specific vertical column spacing. Furthermore, the top secondary beams, main beams, and column supports only provide vertical load bearing, and the top components lack horizontal restraint, becoming cantilevered ends and failing to fully utilize the overall stability of the component assembly. To meet the construction specifications regarding the slenderness ratio of the columns, it is necessary to increase the number or size of the horizontal bars, thereby increasing costs and workload. Summary of the Invention

[0004] The purpose of this invention is to provide a support structure for prefabricated composite slabs that can improve the overall stability of the formwork system, thereby reducing the arrangement of horizontal bars. While meeting the requirements of vertical bearing capacity and overall stability, it can achieve uniformity in the specifications of support bars and connectors, reduce the number of bars, and improve construction efficiency and save materials while ensuring construction quality.

[0005] Another object of the present invention is to provide a construction method for such a support structure.

[0006] To achieve the first objective of the invention, the technical solution adopted is as follows: A support structure for prefabricated composite slabs includes several horizontally arranged horizontal bars and vertically arranged uprights. The horizontal bars include mutually perpendicular X-axis bars and Y-axis bars, forming a mutually perpendicular three-axis system with the uprights along the Z-axis. At each intersecting node, a component connects the uprights and horizontal bars. Each upright has a top support, which is adjustablely connected to the top of the upright. Each top support is connected to an adjacent top support via a horizontal bar. The horizontal bars and uprights, together with the top supports, form a three-dimensional support structure to support the prefabricated composite slabs. The height of the top supports can be adjusted on the uprights to ensure that the horizontal bars of the same layer remain in the same horizontal plane, thereby ensuring that the levelness and thickness consistency of the prefabricated composite slabs manufactured under the entire support structure meet the standards.

[0007] Both the X-axis and Y-axis are bolted to the top support; or: both ends of the X-axis and Y-axis have pins, and at least four centrally symmetrically distributed pin holes are provided at the top; both the X-axis and Y-axis are connected to the top support via pins and pin holes. The top of the upright and the bottom of the top support are interlocked, and the bottom of the top support is threaded to an adjustable retaining ring fitted on the top of the upright. Rotation is used to fix and adjust the height of both. The top support located at the edge of the supporting structure has empty pin holes not connected to the beam, into which independent pins are inserted to ensure even stress distribution when the top support bears the upper load.

[0008] Both ends of the X-axis and Y-axis are equipped with snap-fit ​​connectors. Each snap-fit ​​connector includes two layers of positioning clamps distributed vertically, with a transverse engaging groove between them. This groove engages with a top support. Each layer of positioning clamps includes a slot, allowing for a pin-hole connection via a through-hole pin. The snap-fit ​​connector, through the double positioning clamps located in the transverse engaging groove, provides double-layer stabilization for the pin inserted into the pin hole, effectively improving the connection strength at the nodes of the triaxial system.

[0009] The top support includes a top and a longitudinal connecting part; the longitudinal connecting part is used to connect the uprights in the support structure; the top has several pin holes evenly arranged circumferentially. The top of the upright and the top are inserted into each other, and the longitudinal connecting part is threaded to the top. The top of the top support includes a top plate disposed in the pin holes and a connecting column disposed at the bottom of the top plate. The connecting column is inserted into the cavity at the top of the upright. The longitudinal connecting part includes an adjusting cylinder and lugs disposed on both sides of the adjusting cylinder. The adjusting cylinder and the connecting column are threaded together. By turning the adjusting cylinder with the lugs, the connecting column can move up and down at the top of the upright, thereby ensuring the height consistency of the nodes on the same floor.

[0010] The top support located at the edge of the supporting structure has an empty pin hole that is not connected to the beam, into which an independent pin is inserted. The empty pin hole can be filled with an independent pin that can be removed at any time, which means that the idle state of the pin hole can be adjusted at any time according to the installation position of the top support, and it can also balance the weight of the top support.

[0011] The horizontal members include a main beam along the X-axis and a secondary beam along the Y-axis, with the main beam being taller than the secondary beam. Each upright has a top support and a beam at its top. The X-axis beam directly supports the upper load, and the load is transferred to the entire support structure through connections with the Y-axis beam and top support. This invention eliminates the cantilever ends of the uprights by interlocking the main and secondary beams with the top support, reducing the overall slenderness ratio of the uprights. This merges the horizontal members below the original main and secondary beams with the main and secondary beams, reducing the number of horizontal members needed under the same load, increasing the worker's workspace, and improving construction efficiency. Besides the main beams and side beams, the remaining horizontal members primarily connect the nodes, assist in load-bearing, and ensure the stability of the entire support structure.

[0012] A transition connection is provided between the main beam and the fastener; the double-layer positioning clamp of the fastener has a wedge-shaped structure, and the width of the fastener near the transition connection is the same as the width of the horizontal bar, gradually narrowing away from the transition connection. The fastener effectively improves the connection strength of the connection node between the horizontal bars, and the double-layer positioning clamp gradually narrows from the inside to the outside, making the pin inserted into it stable. The transition connection is an arc-shaped reinforcement part, used to smoothly connect the main beam and the fastener.

[0013] To achieve the second objective of the invention, the technical solution adopted is as follows: a support construction method for prefabricated composite slabs, comprising the following steps:

[0014] 1) Using the aforementioned support structure, design a suitable support system scheme based on the engineering attributes and load parameters. Select an appropriate module for the longitudinal and transverse spacing of the uprights. The lengths of the X-axis and Y-axis members must match the module of the longitudinal and transverse spacing of the uprights and must also meet the calculations for bending resistance, shear resistance, and deflection. Adjustable supports must meet the calculations for adjustable supports. The upright spacing must be adjusted according to the overall slenderness ratio of the uprights. The uprights as a whole must meet the calculations for slenderness ratio and stability. The entire support structure must meet the calculations for height-to-width ratio and overturning resistance.

[0015] 2) Implement according to the design plan. First, measure and lay out the adjustable base, then install the sweeping rod and connect the uprights and horizontal bars layer by layer. Then, connect the adjustable top support with pin holes to the uprights at the required height through threads. The adjustable top support can be raised and lowered on the uprights to adjust the height of the entire formwork frame, thereby adapting to different construction height requirements. Then, insert the pins at both ends of the X-axis rod and Y-axis rod into the corresponding pin holes. In this way, the X-axis rod and Y-axis rod are connected to the uprights as a whole. Finally, insert independent pins into the empty pin holes of the top support located at the edge of the support structure that are not connected to the beam.

[0016] 3) According to the construction schedule, when the concrete strength reaches the preset requirements, the horizontal bars can be removed, leaving only the vertical bars and the top support system. The removed horizontal bars can be added to the prefabricated composite slab construction of the new floor.

[0017] The main beam in the X direction uses square steel tubes. The adjustment of the main beam length (pole spacing) must simultaneously meet the requirements of bending resistance, shear resistance, deflection calculation and the module of the lower horizontal bar. Based on this, the maximum pole spacing of beams with different cross-sections, materials and in the X direction can be calculated first according to the beam bending resistance, shear resistance and deflection calculation formulas. From beams with different cross-sections and materials, the type of main beam in the X direction that meets the requirements and saves money can be selected.

[0018] This invention connects the X and Y direction beams with adjustable top supports featuring pin holes, adding horizontal constraints to the top of the traditional formwork system and removing the cantilever ends. This increases the overall slenderness ratio of the uprights, allowing for a larger range of upright spacing during formwork design and reducing the need for horizontal bars. For example, in designing a standard floor bay formwork system with a height of 2.9m, using Ф48×3.0 steel pipes as uprights, and a bottom 350mm high ground bracing, the top structure uses the adjustable top supports with pin holes and matching square steel pipe X and Y direction beams of this invention. Based on the standard slenderness ratio calculation and upright stability calculation formulas, the maximum spacing for the Ф48×3.0 steel pipe is calculated to be 2085mm, requiring only three horizontal bars. When using Ф60×3.2 steel pipes as uprights, the maximum spacing is 2715mm, requiring only two horizontal bars. Compared to existing traditional support systems, when the uprights are made of Ф48×3.0 steel pipes, the maximum step distance is only 1605mm, and four horizontal bars need to be installed.

[0019] The beams are divided into main beams along the X-axis and secondary beams along the Y-axis. The main beams are rectangular steel tubes, while the secondary beams can be ordinary cylindrical steel tubes. The height of the main beams is greater than that of the secondary beams. The main beams in the X-direction bear the upper load and also serve to connect the whole structure, while the secondary beams in the Y-direction do not directly contact the upper load and only serve as connecting members of the whole structure.

[0020] Therefore, the present invention has the following beneficial effects:

[0021] (1) Using top supports and components as node connectors can improve the overall stability of the formwork system, thereby reducing the arrangement of horizontal bars. On the basis of meeting the vertical bearing capacity and overall stability, it can achieve uniformity of support rods and connectors, reduce the number of rods, and improve construction efficiency and save materials while ensuring construction quality.

[0022] (2) The fastener uses double-layer positioning clamps set in the transverse engagement groove to stabilize the pin inserted into the pin hole from both the top and bottom, effectively improving the connection strength at the node of the triaxial system.

[0023] (3) The insertion hole of the double-layer positioning hoop is a wedge-shaped structure, and the independent pin matches the shape of the insertion hole. When the pin is inserted into the insertion hole, the pin is effectively fixed in the horizontal plane by the double-layer positioning hoop tightened on both sides. The upper and lower positioning hoops are vertically positioned by the pin in a two-point line manner, ensuring that the pin passing through the pin hole will not loosen, further improving the installation stability of the support structure. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the support structure in Example 1.

[0025] Figure 2 yes Figure 1 Schematic diagram of the connection between the top support and the beam.

[0026] Figure 3 yes Figure 1 A schematic diagram of the structure of the top support.

[0027] Figure 4 This is a schematic diagram of the support structure in Example 2.

[0028] Figure 5 yes Figure 4 A magnified view of a portion of point A in the middle.

[0029] The components in the diagram are marked as follows: secondary beam 1, main beam 2, independent pin 3, top support 4, upright 5, horizontal bar 6, component 7, pin 8, pin hole 9, top 10, longitudinal connection 11, adjustable positioning ring 12, fastener 13, transverse locking groove 14, transition connection 15, base 16, and connection hole 17. Detailed Implementation

[0030] Example 1

[0031] like Figure 1 , 2 As shown, the support structure of this embodiment includes two layers of horizontally arranged horizontal bars 6 and several vertically arranged uprights 5. The horizontal bars can be divided into mutually perpendicular X-axis bars and Y-axis bars, forming a mutually perpendicular three-axis system with the Z-axis of the uprights. At each intersecting node, the uprights and horizontal bars are fixedly connected by components 7. Each upright has a top support 4, which is connected to the top of the upright through a longitudinal connecting part 11 and an adjustable positioning ring 12. The head of the top support 4 is a top 10, which is a perforated circular tray with four pin holes 9. The four pin holes are symmetrically distributed in two groups, with two opposite pin holes forming one group, and have the same shape. The component is a perforated circular tray with the same top structure as the top support, which is fixedly connected to the upright and used to connect the horizontal bars of the same layer to ensure the stability between the uprights.

[0032] The supporting structure consists of a main beam 2 on the X-axis and a secondary beam 1 on the Y-axis at the top. The main beam is taller than the secondary beam. The main beam 2 bears the upper load and also serves to connect the entire structure, while the secondary beam 1 does not directly contact the upper load and only acts as a connecting member. Both ends of the main and secondary beams have pins 8, whose shape and dimensions match the pin holes 9 on the top supports. The beams and top supports are connected as a whole through the pins 8 and pin holes 9. In this way, each top support is connected to its adjacent top support via a beam on the X-axis or Y-axis. Top supports located at edges or corners have only two or three adjacent top supports, thus having empty pin holes not connected to beams. Individual pins 3 are inserted into these empty pin holes to ensure even stress distribution when the top support bears the upper load.

[0033] like Figure 3 As shown in this embodiment, the support structure of the prefabricated composite slab includes several horizontally arranged horizontal bars and vertically arranged vertical bars. The horizontal bars include mutually perpendicular X-axis bars and Y-axis bars, forming a mutually perpendicular three-axis system with the vertical bars along the Z-axis. At each intersecting node, the vertical bars and horizontal bars are connected by top supports. Each vertical bar has a top support, which is adjustablely connected to the top of the vertical bar. Each top support is connected to an adjacent top support via a horizontal bar. The horizontal bars and vertical bars, together with the top supports, form a three-dimensional support structure to support the prefabricated composite slab. The height of the top supports can be adjusted on the vertical bars to ensure that the horizontal bars of the same layer remain in the same horizontal plane, thereby ensuring that the levelness and thickness consistency of the prefabricated composite slab manufactured under the entire support structure meet the standards.

[0034] Both the X-axis and Y-axis are bolted to the top support; or: both ends of the X-axis and Y-axis have pins, and at least four centrally symmetrically distributed pin holes are provided at the top; both the X-axis and Y-axis are connected to the top support via pins and pin holes. The top of the upright and the bottom of the top support are interlocked, and the bottom of the top support is threaded to an adjustable retaining ring fitted on the top of the upright. Rotation is used to fix and adjust the height of both. The top support located at the edge of the supporting structure has empty pin holes not connected to the beam, into which independent pins are inserted to ensure even stress distribution when the top support bears the upper load.

[0035] The top support includes a top and a longitudinal connecting part; the longitudinal connecting part is used to connect the uprights in the support structure; the top has several pin holes evenly arranged circumferentially. The top of the upright and the top are inserted into each other, and the longitudinal connecting part is threaded to the top. The top of the top support includes a top plate disposed in the pin holes and a connecting column disposed at the bottom of the top plate. The connecting column is inserted into the cavity at the top of the upright. The longitudinal connecting part includes an adjusting cylinder and lugs disposed on both sides of the adjusting cylinder. The adjusting cylinder and the connecting column are threaded together. By turning the adjusting cylinder with the lugs, the connecting column can move up and down at the top of the upright, thereby ensuring the height consistency of the nodes on the same floor.

[0036] The top support located at the edge of the supporting structure has an empty pin hole that is not connected to the beam, into which an independent pin is inserted. The empty pin hole can be filled with an independent pin that can be removed at any time, which means that the idle state of the pin hole can be adjusted at any time according to the installation position of the top support, and it can also balance the weight of the top support.

[0037] The horizontal members include a main beam along the X-axis and a secondary beam along the Y-axis, with the main beam being taller than the secondary beam. Each upright has a top support and a beam at its top. The X-axis beam directly supports the upper load, and the load is transferred to the entire support structure through connections with the Y-axis beam and top support. This invention eliminates the cantilever ends of the uprights by interlocking the main and secondary beams with the top support, reducing the overall slenderness ratio of the uprights. This merges the horizontal members below the original main and secondary beams with the main and secondary beams, reducing the number of horizontal members needed under the same load, increasing the worker's workspace, and improving construction efficiency. Besides the main beams and side beams, the remaining horizontal members primarily connect the nodes, assist in load-bearing, and ensure the stability of the entire support structure.

[0038] The following is the design process of this embodiment.

[0039] 1.1.1 Erecting poles

[0040] This design optimizes the support frame using a disc-lock system. A ground-level bracing bar is installed at a height of 350mm at the bottom. The main beams and secondary beams at the top are connected to the upright supports via a socket joint. The uprights have no cantilever ends; the maximum cantilever length is calculated as the ground-level bracing bar height of 350mm. Based on the slenderness ratio calculation and upright stability calculation formulas, the maximum spacing for Ф48×3.0 steel pipes is calculated to be 2085mm, requiring three horizontal bracing bars. For Ф60×3.2 steel pipes, the maximum spacing is 2715mm, requiring only two horizontal bracing bars. The upright spacing is determined based on the main beam's bending, shear, and deflection calculation formulas, yielding the maximum upright spacing for main beams of different cross-sections and materials.

[0041] 1. Slenderness ratio of Ф48×3.0 steel pipe

[0042] l 01 =β H h+2ka=1×1500+2×0.6×350=1770mm

[0043] l0=β H ηh = 1 × 1.05 × 1500 = 1575 mm

[0044] λ=max[l 01 ,l0] / i=1770 / 15.9=111.321≤[λ]=150

[0045] 2. Stability of Ф48×3.0 steel pipe uprights

[0046] According to Formula 5.3.1-2 of the "Safety Technical Standard for Socket-Type Disc-Lock Steel Pipe Scaffolding in Building Construction" JGJ / T231-2021, when considering wind loads, a combination factor of 0.9 needs to be considered for variable loads.

[0047] Main beam verification q1=γ0×[1.3×(G 1k +(G 2k +G 3k )×h1)+1.5×0.9×Q 1k ]×b=1×[1.3×(1.5+(24+1.1)×0.07)+1.5×0.9×3]×1.2=9.941kN / m

[0048] The design value of the main beam's self-weight is g = γ0 × γ G ×g k =1 × 1.3 × 0.036 = 0.047 kN / m

[0049] The design load on the main beam is q = q1 + g = 9.941 + 0.047 = 9.988 kN / m

[0050] Substituting the values ​​back into the calculation, we get:

[0051] R1 = 5.993 kN, R2 = 5.993 kN

[0052] Bottom upright section (maximum step distance upright section):

[0053] λ1=l 01 / i = 1770 / 15.9 = 111.321

[0054] From the table, we find that υ = 0.398

[0055] Ignoring wind load:

[0056] N = Max[R1,R2] + 1 × γ G ×q×H=Max[5.993,5.993]+1×1.3×0.15×2.9=6.558kN

[0057] f = N / (υ1A) = 6.558 × 10 3 / (0.398×424)=38.862N / mm 2 ≤[f] / γ R =300 / 1=300N / mm 2

[0058] Requirements met!

[0059] Considering wind load:

[0060] M w =γ0×γQ υ c ω k ×l a ×h 2 / 10 = 1 × 1.5 × 0.9 × 0.199 × 1.2 × 1.5 2 / 10=0.073kN·m

[0061] N w =Max[R1,R2]+1×γ G ×q×H+M w / l b =Max[5.993,5.993]+1×1.3×0.15×2.9+0.073 / 1.2=6.619kN

[0062] f = N w / (υ1A)+M w / W=6.619×10 3 / (0.398×424)+0.073×10 6 / 4490=55.481N / mm 2 ≤[f]

[0063] / γ R =300 / 1=300N / mm 2

[0064] Requirements met!

[0065] 3. Slenderness ratio of Ф60×3.2 uprights

[0066] l 01 =β H γhˊ+2ka=1×0.9×2405+2×0.6×350=2584.5mm

[0067] l0=β H ηh=1×1.05×2405=2525.25mm

[0068] λ=max[l 01 , l0] / i=2584.5 / 20.1=128.582≤[λ]=150

[0069] 4. Stability of Ф60×3.2 uprights

[0070] According to Formula 5.3.1-2 of the "Safety Technical Standard for Socket-Type Disc-Lock Steel Pipe Scaffolding in Building Construction" JGJ / T231-2021, when considering wind loads, a combination factor of 0.9 needs to be considered for variable loads.

[0071] Main beam verification

[0072] q1=γ0×[1.3×(G 1k +(G 2k +G 3k )×h1)+1.5×0.9×Q 1k ]×b=1×[1.3×(1.5+(24+1.1)×0.07)+1.5×0.9×3]×

[0073] 1.2 = 9.941 kN / m

[0074] The design value of the main beam's self-weight is g = γ0 × γ G ×g k =1 × 1.3 × 0.036 = 0.047 kN / m

[0075] The design load on the main beam is q = q1 + g = 9.941 + 0.047 = 9.988 kN / m

[0076] Substituting the values ​​back into the calculation, we get:

[0077] R1 = 5.993 kN, R2 = 5.993 kN

[0078] Pole erection section:

[0079] λ1=l 01 / i = 2584.5 / 20.1 = 128.582

[0080] From the table, we find that υ = 0.309

[0081] Ignoring wind load:

[0082] N = Max[R1,R2] + 1 × γ G ×q×H=Max[5.993,5.993]+1×1.3×0.15×2.9=6.558kN

[0083] f = N / (υ1A) = 6.558 × 10 3 / (0.309×571)=37.168N / mm 2 ≤[f] / γ R =300 / 1=300N / mm 2

[0084] Requirements met!

[0085] Considering wind load:

[0086] M w =γ0×γ Q υ c ω k ×l a ×h 2 / 10=1×1.5×0.9×0.199×1.2×2 2 / 10=0.129kN·m

[0087] N w =Max[R1,R2]+1×γ G ×q×H+M w / l b =Max[5.993,5.993]+1×1.3×0.15×2.9+0.129 / 1.2=6.666kN

[0088] f = N w / (υ1A)+M w / W=6.666×10 3 / (0.309×571)+0.129×10 6 / 7700=54.534N / mm 2 ≤[f]

[0089] / γ R =300 / 1=300N / mm 2

[0090] Requirements met!

[0091] Table 1.1 Design Parameters for Pole Laying Stairs

[0092]

[0093]

[0094] Based on the standard slenderness ratio calculation and pole stability calculation formula, the maximum step distance for Ф48×3.0 steel pipe is calculated to be 2085mm, requiring a ground-level bracing rod and two horizontal bars. The maximum step distance for Ф60×3.2 steel pipe is 2715mm, requiring only a ground-level bracing rod and one horizontal bar. Compared with the traditional formwork system, the overall system is significantly simpler, more spacious, and saves materials.

[0095] 1.1.2 Main Beam

[0096] The design parameters of the main beam of the formwork support are shown in Table 1.2. The spacing between the uprights is calculated using the formulas for the bending, shear, and deflection resistance of the main beam. The maximum upright spacings L1, L2, and L3 for different cross-sections and materials of the main beam are obtained through single-variable calculation in an EXCEL spreadsheet. The minimum value among these three is taken as the maximum upright spacing L for this support scheme. Finally, the model of the main beam is determined through scheme design and modular control.

[0097] 1. Bending resistance calculation

[0098] σ=M max / W≤[f] / γ R=205 N / mm 2

[0099] 2. Shear resistance check

[0100] Steel pipe: τ max =2V max / A=≤[τ] / γ R =125 / 1=125N / mm 2

[0101] Channel steel: τ max =V max / (8I z δ)[bh0 2 -(b-δ)h 2 ]≤[τ] / γ R =125 / 1=125N / mm 2

[0102] 3. Deflection Calculation

[0103] Cross-China max ≤[ν]=min{L / 150,10}

[0104] Table 1.2 Calculation parameters of main beam stress

[0105]

[0106]

[0107] 1.1.3 Formwork Support Design Scheme

[0108] Based on the required maximum step distance and maximum spacing of the uprights, and referring to the module of the horizontal bar of the disc-lock formwork support frame, a formwork support scheme can be formulated for different bay sizes. The specific parameters of the formwork support scheme are shown in Table 1.3 below.

[0109] Table 1.3 Design parameters of the overall formwork support

[0110]

[0111]

[0112] The supporting structure consists of a main beam 2 on the X-axis and a secondary beam 1 on the Y-axis at the top. The main beam can be made of square steel tubing or conventional steel tubing, ensuring the support strength meets design requirements. Because square steel tubing has better bending resistance, in this embodiment, the main beam is preferably made of Q345 square steel tubing (60x40x25mm), which offers better load-bearing capacity, installation performance, and operational comfort. The main beam is taller than the secondary beam. The main beam 2 bears the upper load and also serves as a connector, while the secondary beam 1 does not directly contact the upper load and only acts as a connecting member. Both ends of the main and secondary beams have pins 8, whose shape and dimensions match the pin holes 9 on the top support. The beams and top supports are connected as a whole via the pins 8 and pin holes 9. In this way, each top support is connected to its adjacent support via a beam on the X-axis or Y-axis.

[0113] The top supports located at the edge or corner have only two or three adjacent top supports, thus having empty pin holes that are not connected to the beam. Independent pins 3 are inserted into these empty pin holes to ensure that the top supports bear the load evenly when they bear the upper load.

[0114] According to calculations, in this embodiment, after the concrete reaches the preset safety strength requirement, operators can remove all horizontal bars except for the main beam and secondary beam. The support stability can be guaranteed solely by the structure consisting of the uprights, main beam, and secondary beam. This early removal scheme can improve the turnover rate of horizontal bars, thereby effectively improving construction efficiency. In this embodiment, a base 16 is provided at the bottom of the upright, which ensures that the upright remains stable after the early removal scheme is implemented.

[0115] Example 2

[0116] Unlike Example 1, as Figure 4 , 5 As shown, in this embodiment, both ends of the X-axis and Y-axis are provided with snap-fit ​​connectors 13. Each snap-fit ​​connector includes two layers of positioning clamps distributed vertically, with a transverse engaging groove 14 between the two layers. The transverse engaging groove engages with a top support or component. Each of the two layers of positioning clamps includes a slot, and the two layers of positioning clamps and pin holes can be connected by an independent through-hole pin. The snap-fit ​​connector, through the double positioning clamps located in the transverse engaging groove, provides double stability to the pin inserted into the pin hole, effectively improving the connection strength at the nodes of the triaxial system.

[0117] A transition connection 15 is provided between the main beam and the fastener. The fastener's double-layer positioning clamp is a wedge-shaped structure. The width of the fastener near the transition connection is the same as the width of the horizontal bar, and the fastener gradually narrows away from the transition connection. The fastener effectively improves the connection strength of the connection nodes between the horizontal bars. The double-layer positioning clamp gradually narrows from the inside to the outside, making the independent pins inserted into it stable. The transition connection is an arc-shaped reinforcement part, used to smoothly connect the main beam and the fastener, so that the main beam, which is higher than the secondary beam, is stably connected to the top support under the main load, thereby achieving the stability of the entire support structure.

[0118] In this embodiment, the use of a fastener with double-layer positioning clamps enables multi-layer fixation of the components and top support. Since the insertion holes of the double-layer positioning clamps are wedge-shaped, and the independent pins match the shape of the insertion holes, when the pin is inserted, it is effectively fixed horizontally by the double-layer positioning clamps tightened on both sides. The upper and lower positioning clamps vertically position the pin in a two-point-one-line manner, ensuring that the pin penetrating the pin hole will not loosen, further improving the installation stability of the support structure. In addition, the top support in this application also has several connecting holes 17 between the pin holes. When constructing high-height prefabricated composite slabs, due to the large length of the uprights, to avoid the base bending at the root due to the large offset moment of the uprights, diagonal braces are set between the diagonally distributed top supports / components in the same layer to further increase the overall strength of the support structure. At this time, independent pins can be installed using the connecting holes to fix the diagonal braces. Therefore, the connecting holes at the top can improve the upper limit of the overall support structure's strength and versatility. Except as described above, the other technical features in this embodiment are the same as those in Embodiment 1.

Claims

1. A support structure for a prefabricated composite slab, characterized in that: It includes several horizontally arranged horizontal bars and vertically arranged vertical bars, wherein the horizontal bars include mutually perpendicular X-axis bars and Y-axis bars, which together with the vertical bars along the Z-axis form a mutually perpendicular three-axis system; At each intersecting node, the vertical and horizontal bars are connected by a component; Each pole has a top support that is adjustablely attached to the top of the pole; Each support is connected to the adjacent support via a horizontal bar, forming a three-dimensional support network; The horizontal bar includes a main beam arranged along the X-axis and a secondary beam arranged along the Y-axis. The height of the main beam is greater than that of the secondary beam. The main beam and the secondary beam are inserted into the top support to eliminate the cantilever end of the top of the vertical bar. The top support includes a top and a longitudinal connecting part; the longitudinal connecting part is used to connect the upright in the support structure; the top is evenly provided with a number of pin holes along the circumference. The ends of the main beam and the secondary beam are provided with pins that mate with the pin holes. By inserting the pins into the pin holes, a rigid connection is achieved between the top support and the horizontal bar, thereby eliminating the cantilever end at the top of the upright.

2. The support structure for a prefabricated composite slab according to claim 1, characterized in that: The top has at least four pin holes that are centrally symmetrically distributed.

3. The support structure for a prefabricated composite slab according to claim 1, characterized in that: Both ends of the X-axis and Y-axis are provided with snap-fit ​​connectors. The snap-fit ​​connectors include double-layer positioning clamps distributed vertically. A transverse engagement groove is provided between the double-layer positioning clamps. The transverse engagement groove engages with the top support or component. Each double-layer positioning clamp includes a slot. The double-layer positioning clamp and the pin hole can be connected by a pin through insertion.

4. A support structure for a prefabricated composite slab according to any one of claims 2 or 3, characterized in that: The top of the upright and the longitudinal connecting part are inserted and connected. An adjustable positioning ring is threaded onto the longitudinal connecting part, and the adjustable positioning ring is threaded onto the top.

5. A support structure for a prefabricated composite slab according to any one of claims 2 or 3, characterized in that: The top support located at the edge of the supporting structure has an empty pin hole that is not connected to the beam, into which an independent pin is inserted.

6. The support structure for a prefabricated composite slab according to claim 3, characterized in that: A transition connection is provided between the main beam and the fastener.

7. The support structure for a prefabricated composite slab according to claim 6, characterized in that: The double-layer positioning clamp of the fastener has a wedge-shaped structure. The width of the fastener on the side near the transition connection is the same as the width of the horizontal bar, and the fastener gradually narrows away from the transition connection.

8. A construction method for a support structure for a prefabricated composite slab according to any one of claims 1-7, comprising the following steps: S1: Using the aforementioned support structure, design a suitable support system scheme based on the engineering attributes and load parameters. Select an appropriate module for the longitudinal and transverse spacing of the uprights. The lengths of the main beams and secondary beams must match the module of the longitudinal and transverse spacing of the uprights and must also meet the calculations for bending resistance, shear resistance, and deflection. Adjustable supports must meet the calculations for adjustable supports. The upright spacing must be adjusted according to the overall slenderness ratio of the uprights. The uprights as a whole must meet the calculations for slenderness ratio and stability. The entire support structure must meet the calculations for height-to-width ratio and overturning resistance. S2: Implement according to the design plan. First, measure and lay out the adjustable base. Then, install the sweeping rod and connect the uprights and horizontal bars layer by layer. Next, connect the adjustable top support with pin holes to the uprights at the required height through threads. The adjustable top support can be raised and lowered on the uprights to adjust the height of the entire formwork frame, thereby adapting to different construction height requirements. Then, insert the pins at both ends of the X-axis rod and Y-axis rod into the corresponding pin holes. In this way, the X-axis rod and Y-axis rod are connected to the uprights as a whole. Finally, insert independent pins into the empty pin holes of the top support located at the edge of the support structure that are not connected to the horizontal bars. S3: According to the construction progress, when the concrete strength reaches the preset requirements, the horizontal bars can be removed, leaving only the vertical bars and top supports as the longitudinal support system. The removed horizontal bars can be added to the prefabricated composite slab construction of the new layer.

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