Concrete pouring method for prestressed hollow floor slab

Abstract

The invention provides a prestressed hollow floor slab concrete pouring method, which relates to the technical field of buildings, and adopts two sky pumps by taking two mutually perpendicular directions in a horizontal section of a building as a first direction and a second direction respectively. The multiple prestressed hollow floor cover plates are poured from one end to the other end in the first direction and from the middle to the two sides in the second direction, and all the prestressed hollow floor cover plates are poured layer by layer in the vertical direction from bottom to top. According to the invention, at least the technical problems of uncompacted concrete filling, hollowing or vibration leakage during concrete pouring of a prestressed hollow floor slab in a large-span, large-height-difference and large-area building in the prior art can be relieved, and the technical problem of difficult pouring forming caused by easy sliding in the concrete pouring process can be solved; according to some optional technical schemes, the technical problem that the filling box easily floats upwards in the pouring process can be solved, and therefore the construction quality and the construction progress of floor systems of large-span and large-area buildings are effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of construction, in particular to a method for pouring concrete of a prestressed hollow floor slab. Background Art

[0002] In recent years, with the continuous development of construction technology, prestressed hollow floor slabs have been widely used in large-span and large-area buildings due to their superior performance and economy. During construction, it is necessary to pour concrete for multiple rows and columns of prestressed hollow floor slabs. The specific structure of the prestressed hollow floor slabs includes an upper flange plate, a lower flange plate, a filling box and multiple rib beams; multiple rib beams connect the upper flange plate and the lower flange plate, and multiple rib beams surround to form a filling space; the filling box is arranged inside the filling space. This structure can significantly reduce the dead weight of the structure, improve the structural stiffness and seismic performance, and reduce the number of beams and columns by setting a filling box (such as a polystyrene foam filling box) inside and combining it with a prestressed steel bar structure, thereby achieving greater space utilization.

[0003] In actual projects, large exhibition halls, museums, etc. are often used as typical prestressed hollow floor applications, and their design complexity is relatively high. In order to form a large-span, high-clearance exhibition space, the total area of ​​the exhibition hall is generally large, resulting in a large amount of concrete for the prestressed hollow floor slab, which is difficult to pour in one go. At the same time, in order to reduce the deadweight of the floor slab, the thickness of the lower flange plate is usually 80mm or 100mm. During the concrete pouring, affected by the filling box and prestressed steel bars, the concrete at the bottom of the filling box cannot be operated intuitively, and it is easy to have problems such as loose concrete filling, hollowing, and vibration leakage. In addition, in order to meet the architectural effect, some floor slabs will be designed as inclined cantilever slabs. The concrete is easily affected by gravity during the pouring process and slides down, resulting in difficulty in pouring and forming. On the other hand, when using a foam filling box, the filling box may float up due to the action of gravity during concrete pouring, further affecting the progress and quality of concrete pouring. Summary of the invention

[0004] The purpose of the present invention is to provide a method for pouring concrete of a prestressed hollow floor slab, which can effectively improve the construction quality and construction progress of the floor slab of a building with a large span and a large area.

[0005] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions: The embodiment of the present invention provides a method for pouring concrete for a prestressed hollow floor slab, which is used for pouring concrete into each prestressed hollow floor slab of a large-span building, wherein the prestressed hollow floor slab comprises an upper flange plate, a lower flange plate, a filling box and a plurality of rib beams; the plurality of rib beams connect the upper flange plate and the lower flange plate, and the plurality of rib beams surround and form a filling space; the filling box is arranged inside the filling space; two directions perpendicular to each other in a horizontal section of the building are respectively a first direction and a second direction, and the method for pouring concrete for the prestressed hollow floor slab adopts two sky pumps to pour a plurality of the prestressed hollow floor slabs in the order of one end to the other end in the first direction and from the middle to both sides in the second direction, and to pour each of the prestressed hollow floor slabs layer by layer vertically from bottom to top; In every two-layer pouring step, after the concrete of the previous layer has initially set and before it has finally set, the pouring of the next layer of concrete begins until the top layer of concrete is poured.

[0006] In an optional embodiment, a grout overflow hole communicating with the space below the bottom surface of the filling box is provided inside the filling space; and the layer-by-layer pouring includes: Concrete pouring step, pouring from the rib beams around the filling box; The initial vibrating and compacting step is to insert a vibrating rod into the poured concrete for vibrating, and observe from the overflow hole. When floating concrete is found at the bottom of the overflow hole, pour concrete into the overflow hole until the liquid level of the concrete in the overflow hole is higher than the liquid level in the rib beam; And a supplementary vibration and compaction step, inserting a vibrating rod into the overflow hole for vibrating, and stopping the vibration when the liquid level of the concrete in the overflow hole no longer drops, thereby completing the pouring of this layer of concrete.

[0007] In an optional embodiment, during the layer-by-layer pouring process, in the preliminary vibrating and compacting step before pouring the top layer of concrete, concrete is poured into the overflow hole until the liquid level of the concrete in the overflow hole is lower than the surface of the filling box or is flush with the surface of the filling box; And / or, in the concrete pouring step, the concrete is poured with a height of no more than 400 mm in a single time.

[0008] In an optional embodiment, the prestressed hollow floor slab further includes a template assembly used during the pouring process and removed after the pouring is completed; the template assembly includes a keel and a beam bottom template; during the pouring process, the keel is arranged below the beam bottom template to support the beam bottom template, and the beam bottom template is arranged at the bottom of the rib beam to support the rib beam; In the preliminary vibration and compaction step, the vibrating rod is inserted until it contacts the beam bottom formwork.

[0009] In an optional embodiment, the coarse aggregate gradation of the concrete is 10mm-20mm continuous gradation, and the slump of the concrete is 160mm-180mm; And / or, the strength grade of the concrete is C40; And / or, the concrete has an impermeability grade of P8.

[0010] In an optional embodiment, the prestressed hollow floor slab concrete pouring method further comprises: The anti-floating step is to carry out anti-floating treatment on the filling boxes of each prestressed hollow floor slab.

[0011] In an optional embodiment, the prestressed hollow floor slab further includes upper steel bars, lower steel bars, and a formwork assembly used during the pouring process and removed after the pouring is completed; The upper reinforcement includes the hollow area reinforcement located at the top of the filling box and the rib beam top reinforcement located at the top of the rib beam; the lower reinforcement is arranged below the rib beam or the lower flange plate; the formwork assembly includes a keel, a beam bottom formwork and a wooden square; during the pouring process, the keel is arranged below the beam bottom formwork to support the beam bottom formwork, and the beam bottom formwork is arranged at the bottom of the rib beam to support the rib beam; the wooden square is used to support the beam bottom formwork; The anti-floating step comprises: taking the overall thickness of the prestressed hollow floor slab as t, when t<T, adopting one anti-floating method, and when t≥T, adopting two anti-floating methods; wherein: The primary anti-floating method includes: fixing a metal wire on the keel, passing the metal wire upward and tying it to the upper steel bar; The two anti-floating methods include: The first fixation is to fix the metal wire to the wooden square, and pass the metal wire upward from the bottom of the beam bottom template and tie it to the lower steel bar; And the second fixing, use wire to tie the hollow area steel bars and the top steel bars of the rib beam.

[0012] In an optional embodiment, the upper steel bars include upper transverse steel bars and upper longitudinal steel bars; in the primary anti-floating method, when the metal wire is passed upward and tied to the upper steel bars, the metal wire is tied at the intersection of the upper transverse steel bars and the upper longitudinal steel bars.

[0013] In an optional embodiment, in the formwork assembly, the keel includes a main keel and a secondary keel, the main keel is arranged below the beam bottom formwork, the secondary keel is connected to the main keel and supports the beam bottom formwork, and when the metal wire is fixed to the keel, the metal wire is fixed to the main keel.

[0014] In an optional embodiment, T≥750mm; and / or, the diameter of the metal wire is d, d≥3mm.

[0015] In particular, in the content of the present invention, the term "and / or" means that the technical features listed before "and / or" and the technical features listed after "and / or" are designed simultaneously or selectively.

[0016] The embodiments of the present invention can achieve at least the following beneficial effects: The embodiments of the present invention at least alleviate the technical problems existing in the prior art when pouring concrete for prestressed hollow floor slabs in large-span and large-area buildings: the technical problems of loose concrete filling, hollowing or vibration leakage, and the technical problem that the concrete is easily affected by gravity during the pouring process and slides down, resulting in difficulty in pouring and forming, thereby effectively improving the construction quality and construction progress of the floor slabs of large-span and large-area buildings.

[0017] In addition, some optional technical solutions of the embodiments of the present invention can also solve the technical problem that the filling box is easy to float during the pouring process. Please refer to the detailed description of the specific implementation method of the present invention for details. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A plan view of a pouring sequence of a method for pouring concrete of a prestressed hollow floor slab provided by an embodiment of the present invention for an exhibition hall (arrows indicate pouring directions); Figure 2 A schematic diagram of a method for pouring concrete for a prestressed hollow floor slab provided in an embodiment of the present invention, in which each prestressed hollow floor slab is poured layer by layer vertically from bottom to top (arrows indicate pouring directions); Figure 3 The following is a schematic diagram of the steps of pouring layer by layer in the embodiment of the present invention. Figure 1 ; Figure 4 The following is a schematic diagram of the steps of pouring layer by layer in the embodiment of the present invention. Figure 2 ; Figure 5 The following is a schematic diagram of the steps of pouring layer by layer in the embodiment of the present invention. Figure 3 ; Figure 6 The following is a schematic diagram of the steps of pouring layer by layer in the embodiment of the present invention. Figure 4 ; Figure 7 Schematic diagram of the anti-floating method in an embodiment of the present invention.

[0020] Icons: 11-filling box; 12-overflow hole; 2-vibrating rod; 31-keel; 311-main keel; 312-secondary keel; 32-beam bottom formwork; 33-wooden square; 4-upper steel bars; 41-hollow area steel bars; 42-rib beam top steel bars; 5-lower steel bars; 6-metal wire. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that like reference numerals and letters denote similar items in the drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0024] In the description of the present invention, it should be noted that: Unless otherwise clearly specified and limited, the terms "disposed", "installed" and "connected" 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 direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the 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.

[0025] The orientation or position relationship indicated by the terms "upper", "lower", "vertical", etc. is based on the orientation or position relationship shown in the drawings, or is the orientation or position relationship in which the product of the invention is usually placed when used. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply 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.

[0026] The term "and / or" means that the technical features listed before "and / or" and the technical features listed after "and / or" are designed simultaneously or selectively.

[0027] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the features of the following embodiments and the optional embodiments in the embodiments can be combined with each other.

[0028] First, the prestressed hollow floor slab is introduced. The specific structure of the prestressed hollow floor slab includes an upper flange plate, a lower flange plate, a filling box 11 and a plurality of rib beams; the plurality of rib beams connect the upper flange plate and the lower flange plate, and the plurality of rib beams surround and form a filling space; the filling box 11 is arranged inside the filling space. Its structure can significantly reduce the dead weight of the structure, improve the structural rigidity and seismic performance, and reduce the number of beams and columns by arranging a filling box 11 inside (the filling box 11 is made of lightweight filling material, and the specific material includes but is not limited to polystyrene foam) and combining it with a prestressed steel bar structure, thereby achieving greater space utilization. For large-span and large-area buildings, it is necessary to cast concrete for multiple rows and columns of prestressed hollow floor slabs to construct prestressed hollow floor slabs.

[0029] In addition, an introduction to the sky pump is given. In the field of construction, the sky pump usually refers to a concrete pump truck (also called a vehicle-mounted pump or a boom pump). It is a mechanical equipment specially used to transport concrete to high or far places. The main feature of the sky pump is that it is equipped with a long telescopic arm (usually called a placing boom or boom), which can flexibly transport concrete to different locations on the construction site.

[0030] On this basis, the present embodiment provides a method for pouring concrete for a prestressed hollow floor slab, which is used for pouring concrete into each prestressed hollow floor slab of a large-span building, with the two directions perpendicular to each other in the horizontal section of the building being the first direction and the second direction respectively. The method for pouring concrete for the prestressed hollow floor slab adopts two overhead pumps to pour a plurality of prestressed hollow floor slabs in the order from one end to the other end along the first direction and from the middle to both sides along the second direction, and to pour each prestressed hollow floor slab layer by layer vertically from bottom to top; in the aforementioned layer-by-layer pouring process, in every two-layer pouring step, after the concrete of the previous layer is initially set and before it is finally set, the pouring of the next layer of concrete is started until the top layer of concrete is poured.

[0031] In particular, the specific number of pouring layers during layer-by-layer pouring can be designed according to the actual building area. For example, but not limited to, when the slope of the exhibition hall is 8° and the north-south height difference is 4.5m, the entire prestressed hollow floor slab is vertically divided into 15 layers for pouring.

[0032] The method for pouring concrete of the prestressed hollow floor slab provided in this embodiment uses two overhead pumps for synchronous operation, and adopts the pouring sequence of "from one end to the other end along the first direction, and from the middle to both sides along the second direction" (for example, refer to Figure 1 and Figure 2, along the pouring sequence of "from north to south, from the middle to both sides in the east-west direction", it can ensure that the concrete gradually expands outward from the central area, reducing the local accumulation or sliding caused by gravity; at the same time, by pouring layer by layer, it can also ensure that the concrete will not slide due to excessive single pouring volume. Pouring layer by layer is also more conducive to improving the pouring density of concrete and avoiding the problems of loose concrete filling, hollowing or vibration leakage; In addition, in concrete construction, if the interruption time during the pouring process is too long, the previous layer of concrete has been initially solidified and cold joints will be formed when the subsequent concrete continues to be poured. The existence of cold joints will significantly reduce the integrity and durability of the structure, and may become the source of problems such as water seepage and cracks. Therefore, it is very important to take measures to reduce the formation of cold joints during the concrete pouring process. In this embodiment, in the process of pouring layer by layer, in every two layers of pouring steps, the pouring of the next layer of concrete is started after the initial solidification of the concrete poured in the previous layer and before the final solidification, until the top layer of concrete is poured, the formation of cold joints can be avoided. In addition, by reasonably arranging the pouring time and interval of each layer of concrete, it is ensured that the pouring of the next layer starts before the initial solidification of the previous layer of concrete, so as to form a continuous and stable overall structure.

[0033] The above measures can solve the problem of uneven concrete pouring under large span and large height difference conditions, ensure that the concrete can be evenly distributed and accurately reach the designated position, ensure the stability of the concrete during the pouring process, and improve construction quality and efficiency.

[0034] Reference Figures 3 to 6 In an optional implementation of this embodiment, a grouting hole 12 connected to the space below the bottom surface of the filling box 11 is provided inside the filling space of the prestressed hollow floor slab. The formation methods of the grouting hole 12 include but are not limited to: (1) in accordance with the engineering design requirements, a grouting hole 12 is reserved at an appropriate position in the mold for making the filling box 11; (2) some detachable devices or temporary components (such as templates) are used to enclose holes inside the filling space of the floor slab, and the holes are removed after the concrete is initially set, thereby forming the grouting hole 12. Through the grouting hole 12, it is possible to visually see whether the concrete has flowed to the bottom of the filling box 11 and monitor the density of the concrete at the bottom of the filling box 11. The size and position of the grouting hole 12 need to ensure that the flow of concrete can be effectively monitored during the concrete pouring process, and necessary supplementary pouring can be performed.

[0035] On this basis, the specific pouring method of pouring each prestressed hollow floor slab vertically from bottom to top layer by layer includes a concrete pouring step, a preliminary vibration compaction step and a supplementary vibration compaction step in sequence, so as to pour concrete around the filling box 11 between the rib beam area and the upper flange plate and the lower flange plate, specifically: In the concrete pouring step: pouring is carried out from the rib beams around the filling box 11.

[0036] In the preliminary vibrating and compacting step: insert the vibrating rod 2 into the poured concrete for vibrating, observe from the overflow hole 12, and when it is found that there is floating concrete at the bottom of the overflow hole 12, pour concrete into the overflow hole 12 until the liquid level of the concrete in the overflow hole 12 is higher than the liquid level in the rib beam. In this step, pour concrete into the overflow hole 12 until the liquid level of the concrete in the overflow hole 12 is lower than the surface of the filling box 11 or is flush with the surface of the filling box 11.

[0037] In the supplementary vibration and compaction step: insert a vibrating rod 2 into the overflow hole 12 to vibrate until the liquid level of the concrete in the overflow hole 12 stops dropping, then stop vibrating to complete the pouring of this layer of concrete.

[0038] Following the above steps, after the previous layer of concrete has initially set and before the final setting, the pouring of the next layer of concrete begins until the top layer of concrete is poured.

[0039] In this optional embodiment, the concrete filling situation can be observed through the overflow hole 12. When thick slurry is found at the bottom of the overflow hole 12, it indicates that the concrete has begun to flow to the bottom of the filling box 11, but the density still needs to be further confirmed. Then, concrete is poured through the overflow hole 12 to make the concrete liquid level in the overflow hole 12 higher than the liquid level in the rib beam, or even flush with the surface of the filling box 11. Vibrate with the vibrating rod 2 to ensure that each layer of concrete is fully dense, thereby avoiding technical problems such as loose concrete filling, hollowing or vibration leakage. In the concrete pouring step, the concrete can be poured as densely as possible by controlling the single pouring height, and the concrete can be prevented from sliding down due to excessive single pouring volume, thereby further improving the stability of concrete pouring and improving the construction quality. The pouring height can be adjusted according to actual construction needs. For example, but not limited to, when the slope of the exhibition hall is 8° and the north-south height difference is 4.5m, the entire prestressed hollow floor slab is vertically divided into 15 layers for pouring, and the single pouring height of the concrete is controlled not to exceed 400mm, so that each layer of concrete can be fully vibrated, wherein a thinner pouring layer is easier to ensure the uniformity and sufficiency of vibration.

[0040] Reference Figure 3In an optional implementation of this embodiment, the prestressed hollow floor slab also includes a formwork assembly used during the pouring process and removed after the pouring is completed; the formwork assembly includes a keel 31 and a beam bottom formwork 32; during the pouring process, the keel 31 is arranged below the beam bottom formwork 32 to support the beam bottom formwork 32, and the beam bottom formwork 32 is arranged at the bottom of the rib beam to support the rib beam. On this basis, in the preliminary vibration and compaction step, preferably, the vibrating rod 2 is inserted into contact with the beam bottom formwork 32, which can fully ensure that the concrete pouring has a high density when the number of prestressed tendons in the floor slab is large.

[0041] In this embodiment, optionally: the coarse aggregate gradation of the concrete is 10mm-20mm continuous gradation, and the slump of the concrete is 160mm-180mm. Specific selection schemes include, but are not limited to: ordinary Portland cement or other suitable cement types are selected, crushed stone or pebbles with a particle size range of 10mm to 20mm are selected as coarse aggregate, and it is ensured that it is continuously graded, and medium sand or fine sand with a fineness modulus controlled between 2.3-3.0 is selected as fine aggregate (sand), and appropriate amounts of high-efficiency water-reducing agent, air-entraining agent and other admixtures are added as needed, and appropriate amounts of water are added. According to the strength grade, durability index and construction conditions required by the design, the concrete mix ratio is designed and adjusted, and the optimal water-cement ratio, sand ratio and admixture dosage are determined through multiple tests, so that the concrete reaches the slump (160mm-180mm) and strength required by the design, and the concrete is mixed according to the determined ratio.

[0042] If aggregates of a single particle size are used, large gaps will be formed between the aggregates, which is not conducive to obtaining a dense concrete structure. In order to fill these gaps, a large amount of cement mortar will be required, which not only increases the cost, but also may cause the concrete to shrink more, and reduce the crack resistance and durability of the concrete. Continuous grading means that in the particle size distribution of concrete aggregates (coarse aggregates and fine aggregates), particles of various particle sizes are mixed in a certain proportion to form a continuous particle size distribution range. This grading method can minimize the gaps between aggregates, thereby improving the workability and mechanical properties of concrete. Although smaller particle size aggregates can provide better workability and filling effects, they increase the total surface area of ​​the aggregates, which means that more cement slurry is needed to wrap these aggregates, which not only increases the cost, but may also cause the concrete to shrink more, thereby affecting the durability and strength of the concrete. Although larger-sized aggregates can reduce the amount of cement used in concrete to a certain extent and help improve strength, large-particle aggregates may cause uneven internal structure of concrete, affecting the quality of pouring. At the same time, they are more likely to separate during transportation and vibration. Large-particle aggregates are also difficult to pass through areas with dense steel bars, which will affect the density and overall quality of concrete. This optional implementation method designs the coarse aggregate gradation of concrete to be 10mm-20mm continuous gradation, and the slump of concrete is 160mm-180mm, ensuring that the concrete has high fluidity, not only ensuring that the concrete has good passability and operability during the pouring process, but also ensuring that the concrete can achieve good density during the pouring process, which can adapt to complex construction environments and improve construction quality. In particular, for the control of slump, a slump test must be carried out when the concrete enters the site to ensure that it meets the design requirements. If the slump is found to be too large or too small, the water-cement ratio or the amount of admixture should be adjusted in time.

[0043] In addition, for other parameter characteristics of concrete, optionally but not limited to, the strength grade of concrete is preferably designed to be C40; and / or the impermeability grade of concrete is designed to be P8 to ensure the construction quality.

[0044] In addition, with regard to the problem in the prior art that a foam filling box is used, the filling box may float up due to the force of gravity during concrete pouring, thus affecting the progress and quality of concrete pouring. In this embodiment, by pouring layer by layer and strictly controlling the height of each layer, the pressure on the filling box 11 during each pouring can be reduced to a certain extent, thereby reducing the risk of the filling box 11 floating up.

[0045] On this basis, in a further optional implementation of this embodiment, the method for pouring concrete for prestressed hollow floor slabs further includes an additional anti-floating step to perform anti-floating treatment on the filling boxes 11 of each prestressed hollow floor slab. Figures 3 to 7In the optional implementation of this embodiment, the prestressed hollow floor slab includes upper steel bars 4 and lower steel bars 5 in addition to the formwork assembly used during the pouring process and removed after the pouring is completed. The upper steel bars 4 include hollow area steel bars 41 located at the top of the filling box 11 and rib beam top steel bars 42 located at the top of the rib beam; the lower steel bars 5 are arranged below the rib beam or the lower flange plate. In addition to the keel 31 and the beam bottom formwork 32, the formwork assembly also includes a removable wooden square 33; during the pouring process, the keel 31 is arranged below the beam bottom formwork 32 to support the beam bottom formwork 32, and the beam bottom formwork 32 is arranged at the bottom of the rib beam to support the rib beam; the wooden square 33 is used to support the beam bottom formwork 32.

[0046] Key References Figure 7 The above anti-floating step includes: taking the overall thickness of the prestressed hollow floor slab as t, when t<T, adopting one anti-floating method, and when t≥T, adopting two anti-floating methods; wherein: the one anti-floating method includes: fixing the metal wire 6 on the keel 31, passing the metal wire 6 upward and tying it to the upper steel bar 4. The two anti-floating methods include: the first fixing and the second fixing, when the first fixing is to fix the metal wire 6 with the wood 33, passing the metal wire 6 upward from the bottom of the beam template 32 and tying it to the lower steel bar 5; when the second fixing is to use the metal wire 6 to tie the hollow area steel bar 41 and the top steel bar 42 of the rib beam.

[0047] In this optional implementation mode, preferably but not limited to, the diameter of the metal wire 6 is d, d ≥ 3mm, to ensure the structural reliability of the metal wire 6 for binding and fixing, and the metal wire 6 can be selected from but not limited to metal wire structures such as steel wire or iron wire. And / or, preferably but not limited to, the above T ≥ 750mm, for example, taking the three plates on the north side of the exhibition hall with a thickness of 750mm and the three plates on the south side with a thickness of 550mm as an example, T is taken as 750mm, and a single anti-floating method is used for a 550mm thick floor slab, and a double anti-floating method is used for a 750mm thick floor slab, and the specific number and distribution of anti-floating points are designed according to needs.

[0048] In this optional embodiment, the filling boxes 11 of each floor slab are treated with anti-floating properties by means of metal wires 6. This can reduce the weight of the floor slab by using the filling boxes 11, thereby achieving lightweight floor slabs. At the same time, it can prevent the filling boxes 11 from being displaced or floated during concrete pouring, thereby forming a strong and stable prestressed hollow floor slab structure and ensuring construction quality.

[0049] To further increase the structural stability against floating points: In an optional implementation manner of this embodiment, the upper steel bars 4 include upper transverse steel bars and upper longitudinal steel bars. In an anti-floating method, when the metal wire 6 is passed upward and tied to the upper steel bars 4, the metal wire 6 is tied at the intersection of the upper transverse steel bars and the upper longitudinal steel bars.

[0050] In an optional implementation of the present embodiment, in the formwork assembly, the keel 31 includes a main keel 311 and a secondary keel 312, the main keel 311 is arranged below the beam bottom formwork 32, the secondary keel 312 is connected to the main keel 311 and supports the beam bottom formwork 32, and when the metal wire 6 is fixed to the keel 31, the metal wire 6 is fixed to the main keel 311.

[0051] Finally, it should be noted that: 1. The method provided in the embodiments of this specification is not limited to the construction of "exhibition halls", but can also be extended to other similar engineering scenarios; 2. The above embodiments and optional implementation modes in this specification are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above optional implementation modes, or replace part or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. In addition, it is emphasized again that the features of the embodiments in this specification and the optional implementation modes in the embodiments can be combined with each other without conflict.

Claims

1. A method for pouring concrete of a prestressed hollow floor slab, used for pouring concrete into each prestressed hollow floor slab of a large-span building, wherein the prestressed hollow floor slab comprises an upper flange plate, a lower flange plate, a filling box and a plurality of rib beams; the plurality of rib beams connect the upper flange plate and the lower flange plate, and the plurality of rib beams surround and form a filling space; the filling box is arranged inside the filling space; and the method is characterized in that: The two directions perpendicular to each other in the horizontal section of the building are respectively the first direction and the second direction. The method for pouring concrete of the prestressed hollow floor slab adopts two sky pumps to pour a plurality of the prestressed hollow floor slabs in the order of one end to the other end along the first direction and from the middle to both sides along the second direction, and to pour each of the prestressed hollow floor slabs layer by layer from bottom to top vertically; In every two-layer pouring step, after the concrete of the previous layer has initially set and before it has finally set, the pouring of the next layer of concrete begins until the top layer of concrete is poured.

2. The method for pouring concrete of prestressed hollow floor slab according to claim 1, characterized in that: An overflow hole communicating with the space below the bottom surface of the filling box is provided inside the filling space; and the layer-by-layer pouring includes: Concrete pouring step, pouring from the rib beams around the filling box; The initial vibrating and compacting step is to insert a vibrating rod into the poured concrete for vibrating, and observe from the overflow hole. When floating concrete is found at the bottom of the overflow hole, pour concrete into the overflow hole until the liquid level of the concrete in the overflow hole is higher than the liquid level in the rib beam; And a supplementary vibration and compaction step, inserting a vibrating rod into the overflow hole for vibrating, and stopping the vibration when the liquid level of the concrete in the overflow hole no longer drops, thereby completing the pouring of this layer of concrete.

3. The method for pouring concrete of prestressed hollow floor slab according to claim 2, characterized in that: During the layer-by-layer pouring process, in the preliminary vibrating and compacting step before pouring the top layer of concrete, concrete is poured into the overflow hole until the liquid level of the concrete in the overflow hole is lower than the surface of the filling box or is flush with the surface of the filling box; And / or, in the concrete pouring step, the concrete is poured with a height of no more than 400 mm in a single time.

4. The method for pouring concrete of prestressed hollow floor slab according to claim 2, characterized in that: The prestressed hollow floor slab also includes a template assembly used during the pouring process and removed after the pouring is completed; the template assembly includes a keel and a beam bottom template; during the pouring process, the keel is arranged below the beam bottom template to support the beam bottom template, and the beam bottom template is arranged at the bottom of the rib beam to support the rib beam; In the preliminary vibration and compaction step, the vibrating rod is inserted until it contacts the beam bottom formwork.

5. The method for pouring concrete of a prestressed hollow floor slab according to any one of claims 1 to 4, characterized in that: The coarse aggregate gradation of the concrete is 10mm-20mm continuous gradation, and the slump of the concrete is 160mm-180mm; And / or, the strength grade of the concrete is C40; And / or, the concrete has an impermeability grade of P8.

6. The method for pouring concrete of a prestressed hollow floor slab according to any one of claims 1 to 4, characterized in that: The method for pouring concrete of prestressed hollow floor slab also includes: The anti-floating step is to carry out anti-floating treatment on the filling boxes of each prestressed hollow floor slab.

7. The method for pouring concrete of a prestressed hollow floor slab according to claim 6, characterized in that: The prestressed hollow floor slab also includes upper steel bars, lower steel bars, and a formwork assembly used during the pouring process and removed after the pouring is completed; The upper reinforcement includes the hollow area reinforcement located at the top of the filling box and the rib top reinforcement located at the top of the rib beam; the lower reinforcement is arranged below the rib beam or the lower flange plate; the formwork assembly includes a keel, a beam bottom formwork and wooden squares; during the pouring process, the keel is arranged below the beam bottom formwork to support the beam bottom formwork, and the beam bottom formwork is arranged at the bottom of the rib beam to support the rib beam; The wooden square is used to support the beam bottom formwork; The anti-floating step comprises: taking the overall thickness of the prestressed hollow floor slab as t, when t<T, adopting one anti-floating method, and when t≥T, adopting two anti-floating methods; wherein: The primary anti-floating method includes: fixing a metal wire on the keel, passing the metal wire upward and tying it to the upper steel bar; The two anti-floating methods include: The first fixation is to fix the metal wire to the wooden square, and pass the metal wire upward from the bottom of the beam bottom template and tie it to the lower steel bar; And the second fixing, use wire to tie the hollow area steel bars and the top steel bars of the rib beam.

8. The method for pouring concrete of prestressed hollow floor slab according to claim 7, characterized in that: The upper reinforcement includes upper transverse reinforcement and upper longitudinal reinforcement; In the primary anti-floating method, when the metal wire is passed upward and tied to the upper steel bars, the metal wire is tied at the intersection of the upper transverse steel bars and the upper longitudinal steel bars.

9. The method for pouring concrete of prestressed hollow floor slab according to claim 7, characterized in that: In the template assembly, the keel includes a main keel and a secondary keel, the main keel is arranged below the beam bottom template, the secondary keel is connected to the main keel and supports the beam bottom template, and when the metal wire is fixed to the keel, the metal wire is fixed to the main keel.

10. The method for pouring concrete of prestressed hollow floor slab according to claim 7, characterized in that: T≥750mm; and / or, the diameter of the metal wire is d, d≥3mm.

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