Prefabricated large-span reinforced concrete floor

Abstract

The invention relates to the technical field of constructional engineering, in particular to a prefabricated large-span reinforced concrete floor. The floor slab comprises an upper flange with the length extending in the front-back direction, a web is arranged at the lower end of the upper flange, the lower end face of the web is in a downwards-protruding arc shape, and an arc-shaped lower flange matched with the lower end face of the web is arranged at the lower end of the web. The front side and the rear side of the lower end face of the upper flange are each provided with a set of lap joint parts extending downwards, the front end and the rear end of the lower flange extend to the two lap joint parts respectively, and the ends of the lower flange are not lower than the lower end faces of the lap joint parts. The web plate and the lower flange are arc-shaped, the floor slab is lighter in dead weight and is located on a building structure through the lap joint part, on one hand, the contact area is increased, stress is reduced, on the other hand, the shelving end structure is simplified, and shelving end blocking processing complexity is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of construction engineering, and particularly relates to a precast large-span reinforced concrete floor slab. Background Art

[0002] At present, the precast component system in the construction industry has entered a brand-new stage different from the past. Compared with cast-in-place concrete, precast concrete components have the advantages of reducing the usage of concrete and steel bars, reducing the number of on-site workers, shortening the construction period, and correspondingly reducing the total cost.

[0003] As Figure 1 shown, it is a precast reinforced concrete floor slab in the prior art. This kind of floor slab is mainly used in small-span (span less than 6 meters) operations of villas and residences. At the same time, the overall shape of the floor slab is cuboid, with a large thickness and self-weight, and it cannot be used in large-span (span above 9 meters) operations.

[0004] As Figure 2 shown, it is a double-T-shaped precast reinforced concrete floor slab in the prior art, including an upper flange 1 and two webs 2 arranged at intervals along the width direction of the upper flange. Although it can meet large-span operations, due to the uneven ends at both ends, when it is placed on room partitions or exterior walls, the sealing treatment between the placed end of the floor slab and the building is complex. At the same time, the self-weight of the floor slab is large, and the placed end is the end of the lower side of the web, and the area of the placed end is small, resulting in large stress at the contact between the floor slab and the building structure, and the safety factor is limited.

[0005] Therefore, designing a precast large-span reinforced concrete floor slab that is easy to assemble and has high safety is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a precast large-span reinforced concrete floor slab, in which the web and the lower flange are arc-shaped, the self-weight of the floor slab is lighter, and it is seated on the building structure by using the overlapping part. On the one hand, the contact area is increased and the stress is reduced. On the other hand, the structure of the placed end is simplified, and the complex sealing treatment of the placed end is avoided.

[0007] In response to the above technical problem, the technical solution provided by the present invention is a precast large-span reinforced concrete floor slab, including an upper flange extending in the front-rear direction. A web is provided at the lower end of the upper flange. The lower end surface of the web is convex downward in an arc shape. An arc-shaped lower flange adapted to the lower end surface of the web is provided at the lower end of the web. A set of downward-extending overlapping parts are respectively provided on the front and rear sides of the lower end surface of the upper flange. The front and rear ends of the lower flange respectively extend to the two overlapping parts, and the end of the lower flange is not lower than the lower end surface of the overlapping part.

[0008] Furthermore, the front and rear sides of the web respectively extend to the opposite side surfaces of the two lapping portions.

[0009] Furthermore, the opposite side surfaces of the two lapping portions are inclined surfaces extending from the bottom surface of the lapping portion to the lower end surface of the upper flange, and the front and rear ends of the lower flange extend to the corresponding inclined surfaces and are smoothly transitioned with the lower end surface of the lapping portion.

[0010] Furthermore, the left - right width of the lapping portion is adapted to the left - right width of the upper flange.

[0011] Furthermore, the left - right width of the lower flange is greater than the left - right width of the web and less than the left - right width of the upper flange.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0013] (1) The floor slab of the present invention includes an upper flange, a web and a lower flange, and its mid - span cross - section is in an I - shape, meeting the requirements of large spans. The web is set as a downward - convex arc structure. On the premise of ensuring the use of large spans, the volume of the floor slab is reduced, thereby reducing the self - weight and using less reinforced concrete.

[0014] Lapping portions are respectively arranged on both sides of the lower end of the upper flange. Using the lapping portions as the supporting ends, the lower end surfaces of the lapping portions are seated on the building structure, increasing the contact area between the floor slab and the building structure, making the stress uniform and reducing the stress. At the same time, the web is wrapped between the upper flange and the lower flange, and the two ends of the lower flange are not lower than the lower end surface of the lapping portion. During assembly, by directly seating the lapping portions on the building structure, the complexity of dealing with the sealing between the supporting ends and the building structure is reduced. On the basis of ensuring safety, the assembly difficulty is reduced.

[0015] At the same time, the arc - shaped web and the arc - shaped lower flange have an outer shape that better fits the bending moment design diagram, and the overall force is more reasonable. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a small - span precast reinforced concrete floor slab in the prior art.

[0017] Figure 2 is a large - span, double - T - shaped precast reinforced concrete floor slab in the prior art.

[0018] Figure 3 is a schematic diagram of the overall structure of a precast large - span reinforced concrete floor slab in Embodiment 1 of the present invention.

[0019] Figure 4 is a front view of a precast large - span reinforced concrete floor slab in Embodiment 1 of the present invention.

[0020] Figure 5It is a precast reinforced concrete floor slab with a large span and a T shape in the prior art.

[0021] Figure 6 It is a precast reinforced concrete floor slab with a large span and an I shape in the prior art.

[0022] Figure 7 It is a sectional reinforcement drawing of a precast large-span reinforced concrete floor slab in Embodiment 1 of the present invention.

[0023] Figure 8 It is a mid-span cross-sectional dimension drawing of a T-shaped precast reinforced concrete floor slab in the prior art under the same design conditions.

[0024] Figure 9 It is a mid-span cross-sectional dimension drawing of an I-shaped precast reinforced concrete floor slab of the present invention and the prior art under the same design conditions.

[0025] Figure 10 It is a bending moment design drawing of I-shaped, T-shaped and the precast reinforced concrete floor slab of the present invention (where Figure A is I-shaped, Figure B is T-shaped, and Figure C is the present invention).

[0026] In the figure: 1. Upper flange; 2. Web; 3. Lower flange; 4. Lapping part; 5. Lapping surface; 6. Upper flange reinforcement; 7. Web reinforcement; 8. Lower flange reinforcement. Detailed implementation manners

[0027] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application: Specific Embodiment 1:

[0029] Refer to Figures 3 to 10 , a precast large-span reinforced concrete floor slab (hereinafter referred to as the floor slab) of the present invention includes an upper flange 1 extending in the front-rear direction. A web 2 is provided at the lower end of the upper flange 1. The lower end surface of the web 2 is in a downwardly convex arc shape. An arc-shaped lower flange 3 adapted to the lower end surface of the web 2 is provided at the lower end of the web 2. The web 2 is wrapped between the upper flange 1 and the lower flange 3.

[0030] On the front and rear sides of the lower end surface of the upper flange 1, a set of downwardly extending lapping parts 4 are respectively provided. The front and rear end surfaces of the lapping parts 4 are flush with the front and rear end surfaces of the upper flange 1. The lower end surface of the lapping part 4 serves as a lapping surface 5 and is directly seated and fixed on the building structure. The front and rear ends of the lower flange 3 respectively extend to the two lapping parts 4, and the end of the lower flange 3 is not lower than the lower end surface of the lapping part 4.

[0031] With such a setting, the floor slab of the present invention includes an upper flange 1, a web 2, and a lower flange 3, and its mid-span cross-section is in an I-shape, meeting the requirements of large spans. The web 2 is set as a downwardly convex arc structure, which reduces the volume of the floor slab and thus reduces its self-weight while ensuring the use of large spans, and the amount of reinforced concrete used is small.

[0032] Lap joints 4 are respectively arranged on both sides of the lower end of the upper flange 1. Using the lap joints 4 as the supporting ends, the lower end surfaces of the lap joints 4 are seated on the building structure, increasing the contact area between the floor slab and the building structure, with uniform stress and reduced stress. At the same time, the web 2 is wrapped between the upper flange 1 and the lower flange 3, and the two ends of the lower flange 3 are not lower than the lower end surfaces of the lap joints 4. During assembly, the web 2 and the lower flange 3 do not contact the building structure, ensuring that the lap joints 4 are directly seated on the building structure, reducing the complexity of the treatment and sealing between the supporting ends and the building structure, and reducing the assembly difficulty on the basis of ensuring safety.

[0033] At the same time, for the arc-shaped web 2 and the arc-shaped lower flange 3, their outer shapes are more conforming to the bending moment design diagram, and the overall force is more reasonable.

[0034] Preferably, in this embodiment, the front and rear sides of the web 2 respectively extend to the opposite side surfaces of the two lap joints 4. This makes the connection between the web 2, the upper flange 1, the lap joints 4, and the lower flange 3 more tightly and stably connected, forming a stable overall structure. When bearing loads, it can better transfer and disperse stress, further improving the overall stability and load-bearing capacity of the precast large-span reinforced concrete floor slab.

[0035] Specifically, the opposite side surfaces of the two lap joints 4 are inclined surfaces extending from the bottom surface of the lap joints 4 to the lower end surface of the upper flange 1. The front and rear ends of the lower flange 3 extend to the corresponding inclined surfaces, and the lower end of the lower flange 3 is smoothly transitioned with the lower end surface of the lap joints 4. When the floor slab is supported, the load can be transferred from the floor slab to the building structure more smoothly, avoiding the generation of stress concentration phenomena.

[0036] Preferably, in this embodiment, the left and right widths of the lap joints 4 are adapted to the left and right widths of the upper flange 1. This increases the area of the lap surface 5, reduces stress, improves stability and safety. At the same time, it simplifies the structural complexity of the supporting ends at both ends of the floor slab, facilitating assembly.

[0037] Preferably, in this embodiment, the left and right widths of the lower flange 3 are greater than the left and right widths of the web 2 and less than the left and right widths of the upper flange 1. The wider lower flange 3 can better disperse the load transmitted from the web 2, increasing the supporting area at the bottom of the floor slab and reducing the stress concentration degree at the bottom. Under the requirements of meeting the force and structural strength, it reduces the material use and the self-weight of the floor slab.

[0038] In this embodiment, as Figure 7As shown in the figure, the upper flange 1 includes multiple groups of upper flange steel bars 6 arranged at intervals in the left-right direction and extending in the front-back direction, and annular upper flange steel bars 6 that enclose the upper flange steel bars 6 extending in the front-back direction. The web 2 includes web steel bars 7 that are annular in the vertical direction and web steel bars 7 that extend in the left-right direction and connect the annular web steel bars 7. The lower flange 3 includes multiple groups of lower flange steel bars 8 arranged at intervals in the left-right direction and extending in the front-back direction, and annular lower flange steel bars 8 that enclose the lower flange steel bars 8 extending in the front-back direction. And the annular web steel bars 7 connect the upper flange steel bars 6 extending in the front-back direction and the lower flange steel bars 8 extending in the front-back direction, so that the entire floor reinforcement forms a whole.

[0039] In the prior art, in addition to double-T floor slabs, large-span floor slabs also include, for example Figure 5 the T-shaped floor slab shown in the figure, and Figure 6 the I-shaped floor slab shown in the figure. Among them, for the T-shaped floor slab shown in Figure 5 the figure, the two sides of the bottom surface of the web 2 serve as lapping surfaces 5. For the I-shaped floor slab shown in Figure 6 the figure, the two sides of the lower end of the lower flange 3 serve as lapping surfaces 5. The resting ends of these two types of floor slabs are also relatively complex, the plugging treatment during installation is difficult, and at the same time, they have a relatively large self-weight, a relatively small lapping surface 5, large stress at the contact between the floor slab and the building structure, and limited safety.

[0040] The following are design examples of the floor slab structure of the present invention and the above-mentioned T-shaped floor slab and I-shaped floor slab under the same design conditions to illustrate that the present invention has a relatively light self-weight on the basis of meeting the same design conditions.

[0041] The design conditions are as follows: the floor slab span is 11.60 meters, the width of each floor slab is 1.20 meters, the permanent load on the slab surface is 2.0 KN / m (excluding the self-weight of concrete), the live load on the slab surface is 4.0 KN / m, and the quasi-permanent coefficient of the live load is 0.5.

[0042] According to the "Code for Design of Concrete Structures" (GB50010-2010), the mid-span section is not less than 0.6 meters, and the mid-span section is uniformly taken as 0.6 meters high (i.e., 600 mm). Considering the arrangement dimensions of the two rows of steel bars at the bottom, the bottom width is not less than 240 mm.

[0043] Therefore, it is obtained that under the condition of meeting the above design conditions, the mid-span section dimensions of the T-shaped floor slab are as shown in Figure 8 the figure, and the mid-span section dimensions of the I-shaped section and the floor slab of the present invention are as shown in Figure 9 the figure. Figure 8 、 9 The dimension unit in

[0044] Calculated according to the volume and density of the materials, the self-weight of the floor slab of the present invention is 2.285 tons, the I-shaped cross-section floor slab is 5.80 tons, and the T-shaped cross-section floor slab is 7.105 tons. The present invention has the lightest self-weight and the least amount of concrete used, and has more advantages in transportation, hoisting, and foundation design.

[0045] At the same time, using the internationally common finite element calculation and analysis software MIDAS Gen, the bending moments of the I-shaped cross-section, T-shaped cross-section, and the floor slab of the present invention are analyzed, and the results are as Figure 10 shown. It can be seen from the figure that the design value of the bending moment of the present invention is the smallest. Therefore, the lower flange steel bars 8 of the lower flange 3 of the floor slab of the present invention can be saved more. And the outer shape of the present invention is basically the same as the bending moment design drawing, and the overall force is more scientific.

[0046] Under the same design conditions, the design parameters of the present invention and the above two existing long-span floor slabs are compared as shown in Table 1 below:

[0047] Table 1 Comparison table of parameters of the floor slab of the prior art and the floor slab of the present invention

[0048] Type Design value of bending moment (KN*m) <![CDATA[Concrete consumption (m 3 )]]> Weight (tons) 1 Prefabricated slab with I-shaped cross-section 256.2 2.320 5.800 2 Prefabricated slab with T-shaped cross-section 282.4 2.842 7.105 3 Prefabricated slab of the present invention 251.0 2.114 5.285

[0049] Therefore, under the same design conditions, the present invention uses the least amount of materials, has the lightest weight, and at the same time has the smallest design value of the bending moment. The ends of the present invention are flat, and it is convenient and fast to be placed on the beam or wall, with uniform force, and there will be no situation of excessive local stress like the existing T-shaped or double-T-shaped. There can be more anchoring points between the slab and the main structure, which is more safe and reliable. Moreover, according to the "Code for Seismic Design of Buildings" (GB50011-2010), the seismic load in the same seismic intensity area is proportional to the structural mass (self-weight). The present invention can reduce the seismic load, thereby reducing the amount of materials used for the main structure to resist the seismic load, ensuring safety and reducing the cost.

[0050] Embodiment 2: This embodiment provides a different lapping part. Different from Embodiment 1, when meeting the actual use situation, the left and right widths of the lapping part can be slightly smaller than the left and right widths of the web. At this time, since the lapping part is in direct contact with the web, the complexity of the supporting end can also be reduced. Moreover, by using the web directly sitting on the building structure, the stress can also be reduced.

[0051] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

[0052] In the description of the embodiments of the present application, it should be noted that if terms such as "upper", "lower", "horizontal", "inner", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the inventive product is commonly placed during use. This is only for the convenience of describing the present application 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, it should not be construed as a limitation to the present application. In addition, terms such as "first", "second", etc. are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0053] In addition, if the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and it does not mean that the structure must be completely horizontal, but it can be slightly inclined.

Claims

1. A precast large-span reinforced concrete floor slab, characterized in that, It includes an upper flange with a length extending in the front-rear direction. A web is provided at the lower end of the upper flange. The lower end face of the web is in a downwardly convex arc shape. An arc-shaped lower flange adapted to the lower end face of the web is provided at the lower end of the web. On the front and rear sides of the lower end face of the upper flange, a set of downwardly extending lapping portions are respectively provided. The front and rear ends of the lower flange respectively extend to the two lapping portions, and the end of the lower flange is not lower than the lower end face of the lapping portion.

2. The precast large-span reinforced concrete floor slab according to claim 1, characterized in that, The front and rear sides of the web respectively extend to the opposite side faces of the two lapping portions.

3. The precast large-span reinforced concrete floor slab according to claim 1, wherein, The opposite side faces of the two lapping portions are inclined surfaces extending from the bottom surface of the lapping portion to the lower end face of the upper flange. The front and rear ends of the lower flange extend to the corresponding inclined surfaces and are smoothly transitioned with the lower end face of the lapping portion.

4. The precast large-span reinforced concrete floor slab according to claim 1, characterized in that, The left-right width of the lapping portion is adapted to the left-right width of the upper flange.

5. The precast large-span reinforced concrete floor slab according to claim 1, characterized in that, The left-right width of the lower flange is greater than the left-right width of the web and less than the left-right width of the upper flange.

Images