Assembled integral type end rib support-free prefabricated slab and construction method

Abstract

The invention belongs to the technical field of assembly type building structures, and relates to an assembly integral type end rib support-free prefabricated slab and a construction method, the assembly integral type end rib support-free prefabricated slab comprises a prefabricated slab main body, a periodic convex rib and a local overlapping structure arranged at at least one end, and upper longitudinal load-bearing steel bars and transverse steel bars with four exposed edges; the thickness of the local overlapping structure is larger than that of the protective layer. The construction method comprises the steps that the end rib plates are prefabricated in a factory, the end rib plates are sequentially overlapped in the end rib direction during field hoisting, the side faces of the plates are connected through a dense splicing structure (reserved full-length overlapping belts and closed steel bar rings) or an overall structure (transverse steel bar overlapping and formwork hoisting pouring), and finally node area concrete is poured. Reliable connection equivalent to cast-in-place is achieved through continuous lap joint of the end rib structures and the steel bars, midspan supports are omitted, the construction efficiency is remarkably improved, and the construction cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of prefabricated building structures, and relates to an assembled integral end rib free-support precast slab and a construction method thereof. Background Art

[0002] With the rapid development of the construction industry, prefabricated building is increasingly becoming a key trend in engineering construction. Compared with the traditional cast-in-place concrete structure on site, prefabricated building significantly improves the construction speed and quality stability by prefabricating components such as beams, slabs, and columns in the factory and then assembling and splicing them on site. At the same time, it reduces the labor cost and construction period, and has been widely adopted in the global construction field.

[0003] In the construction industry of our country, as a kind of prefabricated floor slab technology, the steel bar truss composite slab technology has been widely adopted. The popularization and application of this technology have significantly promoted the transformation and upgrading of the construction industry and brought new development opportunities to the construction field. However, in the actual construction process, the steel bar truss composite slab technology also exposes several technical defects:

[0004] 1. This technology has deficiencies in saving the support frame process. Since the thickness of the conventional steel bar truss composite slab is only about 6 cm, it is difficult to achieve mid-span free support of the composite slab, and temporary support frames usually need to be set up. Such support frames not only increase the construction cost and time, but also occupy a large amount of construction site. Especially in high-rise or super high-rise buildings, the erection and demolition work of the support frames is more difficult, which limits the application range of precast components.

[0005] 2. In the application scenarios of construction, the conventional composite slab has certain limitations. Since this composite slab needs to pour at least 70 mm thick concrete as the composite layer during the construction process, the on-site wet operation workload is still relatively large. The characteristics of this construction method lead to its inapplicability in engineering construction in cold regions or remote regions. In these regions, due to the limitation of climate conditions and the particularity of the construction environment, a solution that can reduce on-site wet operation and improve construction efficiency is needed. However, due to the construction requirements of the conventional composite slab, it is difficult to play its advantages in these specific environments, thus limiting its application range.

[0006] 3. In the construction field, the use of composite slabs is often accompanied by a relatively high steel consumption. In order to ensure that the composite slab has sufficient stiffness during the temporary hoisting and installation stages, a large amount of truss steel bars are required in the conventional design. However, during the normal use stage of the composite slab, these truss steel bars actually rarely or do not participate in the main force-bearing process at all. This design results in the volume steel consumption of the composite slab usually exceeding 120 kg / m 3This approach not only increases the construction cost but also causes a huge waste of social resources because these steel materials are not fully and effectively utilized.

[0007] In summary, the existing precast composite slab technology has many deficiencies in aspects such as construction efficiency, application scenarios, project cost, and resource conservation. Summary of the Invention

[0008] In view of this, the purpose of the present invention is to provide an assembled monolithic end rib-free support precast slab and a construction method to solve the existing problems.

[0009] To achieve the above object, the present invention provides the following technical solution: An assembled monolithic end rib-free support precast slab, including a precast slab, which is connected to the support through a plate end connection joint structure and a plate side connection joint structure. Exposed steel bars are provided on all four sides of the precast slab; upper longitudinal stressed steel bars, lower longitudinal stressed steel bars, and transverse steel bars are arranged inside the precast slab; the upper longitudinal stressed steel bars all extend a set length at the end of the precast slab, and the lap length meets the requirements of the steel bar continuous stress specification; when the precast slab is connected to the beam, at least one end of the precast slab is also provided with a ribbed structure, and the length of this ribbed structure is determined according to the lap length of the upper longitudinal stressed steel bars.

[0010] Optionally, the ribbed structure is composed of periodically arranged ribs and a local composite structure, and the whole is in the shape of a battlement; the height of the rib is less than the thickness of the precast slab, and the thickness of the local composite structure is greater than the concrete cover thickness of the precast slab.

[0011] Optionally, the cross-sectional shape of a single rib is rectangular, trapezoidal, semi-circular, arc-shaped or triangular.

[0012] Optionally, when the precast slab is connected to the beam, when the connection object is a steel structure beam, shear studs are provided on the beam top; when the connection object is a cast-in-place concrete beam, composite beam or fully precast beam, shear-resistant hooked steel bars are embedded on the beam top.

[0013] Optionally, the support is a structural beam or a structural wall, the material is steel structure or concrete, and the construction process of the support is precast or cast-in-place.

[0014] Optionally, the lower longitudinal stressed steel bars may not extend on the side of the precast slab with end ribs and are connected to the support through additional lap steel bars; on the side without end ribs, they extend a set length, and the length extends to the center line of the support.

[0015] Optionally, the transverse steel bars on the side without end ribs can adopt a dense splicing structure or an integral structure; when adopting the dense splicing structure, a through-length composite belt is reserved on the precast slab to expose the transverse steel bars; when adopting the integral structure, the transverse steel bars extend out of the precast slab.

[0016] Optionally, a structural shear key groove can be provided on one side of the endless rib or the full-length overlapping strip.

[0017] A construction method for an assembled monolithic end rib precast slab without support, applicable to an assembled monolithic end rib precast slab as described above, includes the following steps:

[0018] S1, Precast slab fabrication: Precast concrete precast slabs in the factory to ensure that the steel bars at the four sides are exposed and the end ribs are formed;

[0019] S2, Main structure construction:

[0020] S21, If the walls and beams of the main structure adopt precast technology, construct and install precast walls and precast beams, and reserve a temporary placement area for the end of the precast slab on the top surface of the precast walls and precast beams;

[0021] S22, If the walls and beams of the main structure adopt cast-in-place technology, erect the formwork support for the wall and beam areas, and reserve a temporary placement area for the end of the precast slab on both sides of the wall and beam;

[0022] S3, Precast slab hoisting and splicing: Hoist the precast slabs in sequence from one side of the floor to the other side, ensuring that the steel bars in the fully precast cross-section of the rear slab overlap within the end rib area of the front slab;

[0023] S4, Transverse connection treatment:

[0024] S41, Close splicing structure: Reserve a full-length overlapping strip on the side of the precast slab during factory production, and sequentially place closed steel rings and structural full-length steel bars in the full-length overlapping strip;

[0025] S42, Overall structure: The transverse steel bars at the lower part of the precast slab extend a set length and are lapped with the transverse steel bars extending from the adjacent precast slab. The lap length meets the requirements of the steel bar continuous stress specification, and then the local concrete formwork is installed using the suspended form method;

[0026] S5, Post-cast concrete construction: Pour the post-cast concrete in all node areas of the floor structure to complete the pouring of the current floor.

[0027] Optionally, in step S3, during hoisting, the placement direction on one side of the end rib is consistent with the hoisting forward direction, that is, the steel bars extending from the fully precast cross-section of the rear precast slab should be placed on one side of the end rib of the front precast slab to form a continuous lap structure.

[0028] The beneficial effects of the present invention are as follows:

[0029] 1) The structure is reliable in stress and has a wide range of applicable scenarios. In the present invention, the connection between the floor slab and the support, and the connection between the floor slabs are connected by means of steel bar lap anchoring, etc., which meets the requirements of current specifications and the structure is reliable in stress. Most of the end rib brace-free prefabricated panels are prefabricated in factories, and only a very small part at the end or side requires post-cast concrete. Therefore, the amount of wet work on the construction site is very small, breaking through the weather limitation factors of conventional concrete casting, and is especially suitable for house construction in cold areas. In addition, this structural design not only improves construction efficiency, but also reduces dependence on weather conditions, so that the construction progress can be guaranteed even under severe weather conditions, thereby greatly shortening the construction period of the entire construction project.

[0030] 2) Save construction costs and eliminate waste of resources. In the steel truss composite floor slabs that are currently widely used in China, the amount of steel used for the truss steel bars is generally large, which has increased the market price of the composite slabs to a certain extent. The present invention creatively proposes an end rib brace-free prefabricated slab, which can ensure the strength and rigidity of the slab without the use of any truss steel bars, and saves more than 30% of steel compared to traditional composite floors. This not only reduces material costs, but also reduces the environmental impact caused by material waste, which is in line with the current concept of green building and sustainable development.

[0031] 3) Reduce temporary supports and improve construction efficiency. Traditional composite floors have limited support-free capabilities due to their small thickness. The prefabricated panels used in the present invention are all full-section prefabricated structures, which greatly improve the support-free spanning capacity of the mid-span area of ​​the components. There is no need to set up additional formwork support frames in the mid-span area of ​​the floor slabs at the construction site, which greatly reduces construction costs and improves construction efficiency. At the same time, it effectively reduces safety hazards at the construction site. This design not only reduces material and labor costs during the construction process, but also increases construction speed and shortens construction period. It has important economic and time benefits for the entire construction industry.

[0032] In summary, the present invention has shown significant beneficial effects in optimizing construction process, reducing construction cost, expanding application scenarios, improving construction efficiency, and environmental protection and energy saving. It not only provides a new construction method for the construction industry, but also provides strong technical support for achieving sustainable development of buildings and environmental protection.

[0033] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail and preferably below in conjunction with the accompanying drawings, where:

[0035] Figure 1 It is the overall installation schematic diagram of the present invention;

[0036] Figure 2 It is the schematic diagram of the precast slab of the present invention;

[0037] Figure 3 It is the schematic diagram of the cross-section of the rib at the end of the slab of the present invention;

[0038] Figure 4 It is the schematic diagram of the transverse connection treatment method of the close-fitting structure on the side surface of the precast slab of the present invention;

[0039] Figure 5 It is the schematic diagram of the transverse connection treatment method of the overall structure on the side surface of the precast slab of the present invention;

[0040] Figure 6 It is the schematic diagram of the installation method of the end of the precast slab of the present invention and the next slab;

[0041] Figure 7 It is the schematic diagram of the overlapping short steel bars when the rib at the end of the precast slab of the present invention is connected to the beam;

[0042] Figure 8 It is the schematic diagram of the precast slab with ribs at one end in the specific embodiment 1 of the present invention;

[0043] Figure 9 It is the schematic diagram of the precast slab with ribs at both ends in the specific embodiment 2 of the present invention;

[0044] Figure 10 It is the schematic diagram of the precast slab with ribs at three ends in the specific embodiment 3 of the present invention;

[0045] Figure 11 It is the schematic diagram of the precast slab with ribs at four ends in the specific embodiment 4 of the present invention.

[0046] Reference numerals: precast slab 1, support 2, ribbed structure 3, rib 31, partial overlapping structure 32, formwork support 4, additional overlapping steel bar 5, key groove 6, full-length overlapping strip 7, closed steel bar ring and structural full-length steel bar 8. Detailed implementation manners

[0047] The following describes the implementation modes of the present invention through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0048] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams rather than physical diagrams, and should not be construed as a limitation to the present invention; in order to better illustrate the embodiments of the present invention, some components in the drawings will be omitted, enlarged or reduced, which do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0049] In the drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only for illustrative purposes and should not be construed as a limitation to the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0050] Specific Embodiment 1

[0051] Please refer to Figures 1 to 7 , which is an assembled integral end rib free-support precast slab, including a precast slab 1. The precast slab 1 is connected to the support 2 through a plate end connection node structure and a plate side connection node structure. Exposed steel bars are arranged on all four sides of the precast slab 1; upper longitudinal stressed steel bars, lower longitudinal stressed steel bars, and transverse steel bars are arranged inside the precast slab 1; the upper longitudinal stressed steel bars extend a set length at the end of the precast slab 1, and the lap length meets the requirements of the steel bar continuous stress specification; when the precast slab 1 is connected to the beam, at least one end of the precast slab 1 is further provided with a rib structure 3, and the length of the rib structure 3 is determined according to the lap length of the upper longitudinal stressed steel bars. The rib structure 3 is composed of periodically arranged ribs 31 and a partial overlapping structure 32, and the whole is in the shape of a battlement; the height of the rib 31 is less than the thickness of the precast slab 1, and the thickness of the partial overlapping structure 32 is greater than the concrete cover thickness of the precast slab 1.

[0052] In this embodiment, the cross-sectional shape of a single convex rib 31 is a rectangle, but it is not limited to a rectangle, and may be a trapezoid, a semicircle, an arc, or a triangle.

[0053] In this embodiment, when the prefabricated panel 1 is connected to the beam, when the connection object is a steel structure beam, shear studs are provided on the top of the beam; when the connection object is a cast-in-place concrete beam, a composite beam or a fully prefabricated beam, shear-resistant belt hook steel bars are pre-embedded on the top of the beam.

[0054] In this embodiment, the support 2 is a structural beam or a structural wall, the material is a steel structure or concrete, and the construction process of the support 2 is prefabrication or cast-in-place.

[0055] In this embodiment, the lower longitudinal force-bearing steel bars may not extend out on the side of the precast plate 1 with the end ribs, and are connected to the support 2 through additional lap steel bars 5; they extend out to a set length on the side without the end ribs, and the length extends to the center line of the support 2.

[0056] In this embodiment, the transverse reinforcement can adopt a close-fitting structure or an integral structure on the side of the endless rib; when the close-fitting structure is adopted, the prefabricated panel 1 reserves a full-length overlapping strip 7 to expose the transverse reinforcement; when the integral structure is adopted, the transverse reinforcement extends out of the prefabricated panel 1.

[0057] In this embodiment, a shear key groove 6 may be provided on one side of the endless rib or the full-length overlapping belt 7 .

[0058] A construction method for assembling an integral end rib brace-free prefabricated panel, applicable to the above-mentioned integral end rib brace-free prefabricated panel, comprises the following steps:

[0059] a) manufacturing a precast concrete panel 1 in a factory;

[0060] b) When the walls and beams of the main structure are prefabricated, the prefabricated walls and beams (including prefabricated steel structure beams) shall be installed during construction, and a temporary shelving area for the end of the prefabricated slab 1 shall be reserved on the top surface of the prefabricated walls and beams; when the walls and beams of the main structure are cast-in-place, formwork frames for the wall and beam areas shall be set up, and a temporary shelving area for the end of the prefabricated slab 11 shall be reserved on both sides of the walls and beams;

[0061] c) The precast panels 1 are hoisted sequentially from one side of the floor structure, and the placement direction of the end rib side is consistent with the hoisting forward direction, that is, the steel bars of the full precast section of the next precast panel 1 should be placed inside the end rib side of the previous precast panel 1; then the floor slab steel bars are fine-tuned and tied;

[0062] d) At the splicing part on the side of the precast slab 1, when using a close-fitting structure, a continuous lapping zone 7 needs to be reserved on the side of the precast slab 1 during factory production. A closed steel ring and a continuous structural steel bar 8 are sequentially placed in the continuous lapping zone 7. Finally, one longitudinal stressed steel bar of the precast floor slab is respectively tied to the upper part of the transverse distribution steel bars of the precast slab 1. When using an integral structure, the lower transverse steel bars of the precast slab 1 extend by a set length and are lapped with the lower transverse steel bars extended by the adjacent precast slab 1. The lapping length meets the requirements of the steel bar continuous stress specification. Then, the local concrete formwork is installed using the suspended formwork method 4.

[0063] e) Pour the post-cast concrete in all joint areas of the floor structure to complete the pouring of the current floor.

[0064] Specific Embodiment 2

[0065] In this embodiment, different from Specific Embodiment 1, the precast slab 1 used in this embodiment has ribs at both ends.

[0066] Specific Embodiment 3

[0067] In this embodiment, different from Specific Embodiment 1, the precast slab 1 used in this embodiment has ribs at three ends.

[0068] Specific Embodiment 4

[0069] In this embodiment, different from Specific Embodiment 1, the precast slab 1 used in this embodiment has ribs at all four ends.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered by the scope of the claims of the present invention.

Claims

1. An assembled integral end rib brace-free prefabricated panel, comprising a prefabricated panel, wherein the prefabricated panel and the support are connected via a panel end connection node structure and a panel side connection node structure, characterized in that: The four sides of the precast plate are provided with exposed steel bars; the precast plate is provided with upper longitudinal stress-bearing steel bars, lower longitudinal stress-bearing steel bars and transverse steel bars; the upper longitudinal stress-bearing steel bars are extended to a set length at the ends of the precast plate, and the lap length meets the requirements of the continuous stress-bearing specification of steel bars; When the prefabricated plate is connected to the beam, at least one end of the prefabricated plate is also provided with a convex rib structure, the length of which is determined according to the lap length of the upper longitudinal force-bearing steel bars.

2. The assembled integral end rib brace-free prefabricated panel according to claim 1, characterized in that: The convex rib structure is composed of periodically arranged convex ribs and a partially overlapped structure, and is in the shape of a battlement as a whole; The height of the convex rib is less than the thickness of the precast slab, and the thickness of the local overlapping structure is greater than the thickness of the concrete protective layer of the precast slab.

3. The assembled integral end rib support-free prefabricated panel according to claim 2, characterized in that: The cross-sectional shape of a single convex rib is rectangular, trapezoidal, semicircular, arc-shaped or triangular.

4. The assembled integral end rib brace-free prefabricated panel according to claim 1, characterized in that: When the prefabricated panel is connected to the beam, when the connection object is a steel structure beam, shear studs are provided on the top of the beam; when the connection object is a cast-in-place concrete beam, a composite beam or a fully prefabricated beam, shear-resistant belt hook steel bars are pre-embedded on the top of the beam.

5. The assembled integral end rib brace-free prefabricated panel according to claim 1, characterized in that: The support is a structural beam or a structural wall, the material is a steel structure or concrete, and the support construction process is prefabrication or cast-in-place.

6. The assembled integral end rib brace-free prefabricated panel according to claim 1, characterized in that: The lower longitudinal force-bearing steel bars may not extend out on the side of the precast plate with the end ribs, and may be connected to the support through additional lap steel bars; they may extend out to a set length on the side without the end ribs, and the length may extend to the center line of the support.

7. The assembled integral end rib brace-free prefabricated panel according to claim 1, characterized in that: The transverse reinforcement may be closely connected or integrally constructed on one side of the endless rib; When the close-fitting structure is adopted, the prefabricated plate reserves a full-length overlapping strip to expose the transverse reinforcement; when the integral structure is adopted, the transverse reinforcement extends out of the prefabricated plate.

8. The assembled integral end rib brace-free prefabricated panel according to claim 1, characterized in that: A structural shear keyway may be provided on one side of the endless rib or the full-length overlapping strip.

9. A construction method for assembling an integral end rib brace-free prefabricated panel, applicable to an assembled integral end rib brace-free prefabricated panel as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: S1, precast panel production: precast concrete panels in the factory, ensuring that the steel bars on the four sides are exposed and the convex ribs at the ends are formed; S2, main structure construction: S21: If the walls and beams of the main structure are prefabricated, the prefabricated walls and beams shall be installed, and a temporary storage area for the prefabricated board ends shall be reserved on the top surface of the prefabricated walls and beams; S22: If the walls and beams of the main structure are cast in place, formwork frames should be set up in the wall and beam areas, and temporary storage areas for the precast slab ends should be reserved on both sides of the walls and beams; S3, precast slab hoisting and splicing: hoist the precast slabs from one side of the floor slab to the other side in sequence, ensuring that the steel bars of the fully precast section of the rear slab are overlapped in the end rib area of ​​the front slab; S4, lateral connection processing: S41, close-fitting structure: a full-length overlapping strip is reserved on the side of the precast panel during factory production, and a closed steel bar ring and a full-length structural steel bar are sequentially placed in the full-length overlapping strip; S42, overall structure: the lower transverse reinforcement of the precast panel is extended to a set length and overlapped with the lower transverse reinforcement of the adjacent precast panel. The overlap length meets the requirements of the continuous force specification of the reinforcement. Then, the local concrete formwork is installed using a hanging formwork. S5, post-cast concrete construction: pour post-cast concrete in all node areas of the floor structure to complete the pouring of the floor of this layer.

10. A construction method for assembling an integral end rib brace-free prefabricated panel according to claim 9, characterized in that: In step S3, during hoisting, the placement direction of one side of the end rib is consistent with the forward direction of hoisting, that is, the protruding steel bars of the full prefabricated section of the rear prefabricated panel should be placed inside one side of the end rib of the front prefabricated panel to form a continuous lap structure.

Images