A prefabricated reinforced concrete bidirectional multi-ribbed composite slab floor and construction method thereof

Abstract

The present invention belongs to the field of architectural design technology, and specifically relates to an assembled reinforced concrete bidirectional dense-ribbed composite slab floor and a construction method thereof, comprising a bidirectional dense-ribbed prefabricated slab, a composite layer, an end support beam, a side support beam and a post-cast strip, wherein the end support beam, the side support beam and the frame column are spliced ​​to form an installation frame of the bidirectional dense-ribbed prefabricated slab, and both ends of the bidirectional dense-ribbed prefabricated slab are placed on the end support beam, and the bidirectional dense-ribbed prefabricated slab comprises a bottom plate, a middle rib and a side rib; the middle rib and the side rib are protruded downwardly compared with the bottom plate, so that the direction in which the middle rib and the side rib protrude outward is opposite to the setting direction of the composite layer; the present invention realizes the assembly of the reinforced concrete bidirectional dense-ribbed floor, and has the advantages of both the composite plate and the bidirectional dense-ribbed slab, and has the advantages of less on-site wet work of the composite plate, good component quality, saving of formwork and manpower, simple construction, short construction period, etc.; it has the advantages of uniform force transmission, reasonable force bearing, small structural height, light deadweight, large rigidity and good seismic performance of the bidirectional dense-ribbed floor.

Description

Technical Field

[0001] The present invention belongs to the technical field of building design, and in particular relates to an assembled reinforced concrete bidirectional dense-ribbed composite slab floor and a construction method thereof. Background Art

[0002] Cast-in-place reinforced concrete bidirectional multi-ribbed floor slabs have been widely used in some public buildings such as shopping malls, exhibition centers, parking lots, teaching buildings, and large-span residences. Compared with ordinary beam-slab floor slabs, bidirectional multi-ribbed floor slabs have the advantages of more reasonable force, light weight, high rigidity, good integrity, material saving, fast construction speed, space saving and reduced floor height. However, they also have the disadvantages of large on-site steel bar binding, high cost of purchasing, renting, installing and disassembling special membrane shells, and the need for formwork at the bottom, and low assembly rate.

[0003] With the country's vigorous promotion of prefabricated buildings, reinforced concrete floor slabs, as an important part of prefabricated buildings, have a particularly great impact on the assembly rate. The commonly used prefabricated floor slabs are reinforced truss composite slabs, which have the advantages of reducing scaffolding and formwork, saving manpower, speeding up construction, reducing on-site wet work, and saving construction costs. The disadvantage is that it is suitable for smaller spans. The thickness of the composite floor slab is too thick, which increases the deadweight of the floor slab. Especially when the column span is large, secondary beams must be added to meet the bearing capacity and stiffness requirements of the prefabricated part during the construction stage.

[0004] In addition, when calculating composite slabs, cast-in-place slabs are often used for modeling and design. This makes it impossible to simulate the stress changes caused by changes in the height of the compression zone and boundary conditions during the construction and use stages of the composite slabs. In other words, the phenomenon of "advanced stress of tensile reinforcement" cannot be considered. Especially when the self-weight load is large, there will be safety hazards due to the small calculation results. Summary of the invention

[0005] In order to overcome the technical problems existing in the existing reinforced truss composite slabs, the present invention provides an assembled reinforced concrete bidirectional dense-rib composite slab floor, which is a bidirectional dense-rib composite slab floor composed of thin plates and plate ribs with small spacing from ordinary composite slabs. It has the dual advantages of bidirectional dense-rib floor and composite floor, and has the advantages of light weight, high rigidity, low material and labor costs, high assembly rate and fast construction speed.

[0006] The technical solution adopted by the present invention is:

[0007] An assembled reinforced concrete bidirectional dense-ribbed composite slab floor, comprising a bidirectional dense-ribbed precast slab, a composite layer, an end support beam, a side support beam and a post-cast strip, wherein the end support beam, the side support beam and the frame column are spliced ​​to form an installation frame of the bidirectional dense-ribbed precast slab, both ends of the bidirectional dense-ribbed precast slab are placed on the end support beam, the post-cast strip is arranged at the joint of two bidirectional dense-ribbed precast slabs, and the composite layer is stacked on the bidirectional dense-ribbed precast slab to form a bidirectional dense-ribbed composite slab floor;

[0008] The bidirectional dense-rib prefabricated panel includes a bottom plate, middle ribs and side ribs; a plurality of the side ribs are overlapped end to end to form an outer frame of the bidirectional dense-rib prefabricated panel, the middle ribs are cross-distributed transversely and longitudinally to divide the inner side of the outer frame formed by the side ribs into a plurality of bottom plate installation areas, and the bottom plate is embedded in the bottom plate installation areas; the middle ribs and side ribs protrude downwardly compared to the bottom plate, so that the direction in which the middle ribs and side ribs protrude outward is opposite to the setting direction of the laminated layer.

[0009] It is further defined that the longitudinal cross-sectional area A of the longitudinally arranged middle rib bottom reinforcement or the lower chord reinforcement of the triangular steel truss, the longitudinally arranged side rib bottom reinforcement or the lower chord flat reinforcement of the plane steel truss is s1 Both are:

[0010] A s1 =A s0 ·η

[0011]

[0012] Among them, A s0 is the bottom longitudinal reinforcement area of ​​the longitudinally arranged middle rib and side rib at the same position calculated as a whole according to the non-assembled cast-in-place floor;

[0013] η is the magnification factor of the longitudinal reinforcement area at the bottom of the longitudinally arranged middle rib and side rib caused by the advanced stress of the steel bars during assembly;

[0014] β is the ratio of the effective height of the precast middle rib of the two-way multi-rib precast slab to the effective height of the middle rib after superposition;

[0015] α is the ratio of the design value of the self-weight load to the design value of the total load. The self-weight load includes the self-weight of the bidirectional multi-ribbed precast slab and the self-weight of the superimposed layer; the total load includes the self-weight load, surface load and live load, and is multiplied by the corresponding partial coefficient and combination value coefficient;

[0016] M 1 It is the design value of the bending moment caused by the self-weight load at the bottom of the mid-span of the longitudinally arranged middle rib and the longitudinally arranged side ribs in the construction stage according to the single-span simply supported member; M is the design value of the bending moment caused by the total load at the bottom of the mid-span of the longitudinally arranged middle rib and the longitudinally arranged side ribs at the same position.

[0017] It is further defined that a U-shaped frame composed of bottom reinforcement and U-shaped reinforcement or a triangular steel truss is provided in the middle rib; the top end of the U-shaped frame or the triangular steel truss extends through the bottom plate into the overlapping layer, and the bottom end extends to the bottom of the middle rib.

[0018] It is further defined that the triangular steel truss includes an upper chord, a lower chord, a vertical web member, a bottom web member straight reinforcement and a bottom web member diagonal reinforcement, the bottom web member is laid on both sides of the bottom of the triangular steel truss along the length direction of the middle rib, the upper chord is laid above the lower chord along the length direction of the middle rib and is located at the three vertices of an isosceles triangle with the two lower chords, and the vertical web member spans over both sides of the upper chord and extends to the lower chord, forming a closed isosceles triangle ring, and the upper chord extends to the overlapping layer above the bottom plate, the bottom web member straight reinforcement and the bottom web member diagonal reinforcement are distributed at intervals and connected end to end and laid between the two lower chords; the bottom web member straight reinforcement is vertically connected to the lower chord, and the bottom web member diagonal reinforcement is obliquely connected between the two bottom web member straight reinforcements and forms an angle of 30 to 45 degrees with the bottom web member straight reinforcement.

[0019] It is further defined that an S-shaped frame or a plane steel bar truss is provided in the side rib; the top end of the S-shaped frame or the plane steel bar truss extends through the bottom plate into the laminated layer, and the bottom end extends to the bottom of the side rib;

[0020] The plane steel bar truss comprises upper chord flat bars, lower chord flat bars and web member diagonal bars; the lower chord flat bars are laid at the bottom center position of the plane steel bar truss along the length direction of the side ribs, the upper chord flat bars are laid above the lower chord flat bars along the length direction of the middle ribs, and extend to the overlapping layer above the bottom plate, the web member diagonal bars are obliquely connected between the upper chord flat bars and the lower chord flat bars, and the inclination angles of two adjacent web member diagonal bars are opposite, forming an angle of 30 to 60 degrees between the two.

[0021] It is further defined that the integral joint on the side of the bidirectional dense-ribbed precast panel is arranged in the secondary force direction of the composite panel and avoids the maximum bending moment section, the post-cast strip is arranged at the joint of the bidirectional dense-ribbed precast panel, and additional steel bars are arranged in the post-cast strip.

[0022] It is further defined that grooves are provided on the adjacent side ribs of the post-cast strip, and shear keys are formed after pouring non-shrinkage fine stone concrete.

[0023] It is further defined that the bottom longitudinal reinforcements of the transverse center rib and the side rib are directly connected in the post-cast strip or indirectly connected through a connecting plate.

[0024] The construction method of the above-mentioned assembled reinforced concrete bidirectional multi-ribbed composite slab floor comprises the following steps:

[0025] 1) In the factory, first place the bottom plate, middle rib and side rib steel bars in the mold and tie them up, and preset grooves on the side rib molds on both sides, pour concrete at the middle rib and side ribs, vibrate them, and then pour concrete at the bottom plate and vibrate them;

[0026] 2) The top surface of the bottom slab concrete is roughened, and after curing and demoulding, a bidirectional multi-ribbed precast slab can be produced;

[0027] 3) After the end support beam and the side support beam are constructed, the bidirectional multi-rib precast slab is hoisted into place and the two ends are placed on the end support beam;

[0028] 4) Reserve post-casting strips at the joints of adjacent bidirectional dense-rib precast panels, set additional steel bars in the post-casting strips, weld or mechanically connect the bottom longitudinal bars of the transverse middle ribs and side ribs in the post-casting strips, or weld the connecting plates on both sides of the post-casting strips together, and set a bottom mold at the bottom of the post-casting strips as needed;

[0029] 5) Arrange the steel mesh in the superimposed layer, and then use the two-way dense-ribbed precast slab as a permanent bottom form to pour and maintain the concrete of the superimposed layer, thereby completing the construction of the assembled reinforced concrete two-way dense-ribbed superimposed slab floor.

[0030] Further defined, the step 1) is:

[0031] 1.1) The magnification factor of the longitudinal reinforcement area at the bottom of the longitudinal middle rib 3 and the side rib 4 caused by the leading stress of the steel bars is calculated by the following formula:

[0032] Wherein, β is the ratio of the effective height of the prefabricated middle rib of the two-way multi-rib prefabricated slab to the effective height of the middle rib after superposition;

[0033] α is the ratio of the design value of the self-weight load to the design value of the total load. The self-weight load includes the self-weight of the bidirectional multi-ribbed precast slab and the self-weight of the superimposed layer; the total load includes the self-weight load, surface load and live load, and is multiplied by the corresponding partial coefficient and combination value coefficient;

[0034] M 1 It is the design value of the bending moment generated by the self-weight load at the bottom of the mid-span of the longitudinally arranged middle rib and the longitudinally arranged side ribs in the construction stage according to the single-span simply supported member; M is the design value of the bending moment generated by the total load at the bottom of the mid-span of the longitudinally arranged middle rib and the longitudinally arranged side ribs at the same position;

[0035] 1.2) Determine the longitudinal cross-sectional area A of the longitudinally arranged middle rib bottom reinforcement or the lower chord reinforcement of the triangular steel truss, the longitudinally arranged side rib bottom reinforcement or the lower chord flat reinforcement of the plane steel truss s1 Both are:

[0036] A s1 =A s0 ·η

[0037] Among them, A s0 is the bottom longitudinal reinforcement area of ​​the longitudinally arranged middle rib and side rib at the same position calculated as a whole according to the non-assembled cast-in-place floor;

[0038] η is the magnification factor of the longitudinal reinforcement area at the bottom of the longitudinal middle rib and side rib caused by the leading stress of the steel bars during assembly;

[0039] 1.3) According to the bottom longitudinal reinforcement area A of the longitudinally arranged middle rib and side rib s1 Determine the diameter and quantity of steel bars;

[0040] 1.4) According to the conventional design results of the floor slab and the diameter and number of the bottom longitudinal reinforcement of the longitudinal middle rib and side rib, in the factory, the bottom plate, middle rib and side rib reinforcement are first placed in the mold and tied, and recesses are preset on the side rib molds on both sides. Concrete is poured at the middle rib and side rib, and vibrated. Then concrete is poured at the bottom plate and vibrated.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1) The present invention realizes the assembly of reinforced concrete bidirectional dense-rib floor slabs, and has the advantages of both composite slabs and bidirectional dense-rib floor slabs. On the one hand, it has the advantages of composite slabs, such as less on-site wet work, good component quality, saving formwork and manpower, simple construction, and short construction period; on the other hand, it has the advantages of bidirectional dense-rib floor slabs, such as uniform force transmission, reasonable force, small structural height, light dead weight, large rigidity, small deformation, and good seismic performance.

[0043] 2) The present invention solves the problems of insufficient rigidity and heavy deadweight of reinforced truss composite plates with larger spans, especially large-span and large-load structures. The smaller main beam and rib beam sizes increase the net height of the building, and there is no need to add temporary supports during construction. The bearing capacity and deformation requirements of the prefabricated part during the construction stage and the composite plate during the use stage can be met, which simplifies the construction process and speeds up the construction progress.

[0044] 3) The present invention arranges a U-shaped frame or a triangular steel truss in the middle rib, and arranges an S-shaped frame or a plane steel truss in the side rib, which can give full play to the advantages of the U-shaped frame and the triangular steel truss, the S-shaped frame, and the plane steel truss, and effectively reduce the amount of steel bar binding, realize automated production and speed up the construction progress. At the same time, it is convenient for steel bar positioning, ensures the thickness of the concrete protective layer and improves the bearing and deformation resistance of the structure. In addition, the arrangement of the side ribs can, on the one hand, serve as lateral formwork between the rib beams when the post-cast concrete superposition layer and the post-cast belt are on the support beams of the two-way dense-rib precast slabs. On the other hand, shear keys are arranged thereon, which can increase the bonding surface of the concrete, ensure the continuity of the vertical shear force transmission of the transverse rib beams, and improve the integrity of the two-way dense-rib floor.

[0045] 4) The present invention changes the traditional extensive envelope design method of the composite slab. According to the fact that the actual initial stress in the longitudinal reinforcement at the bottom of the mid-span of the rib beam caused by the change of the effective height of the rib beam and the boundary conditions of the support during the construction stage and the use stage due to the self-weight load is greater than the steel stress calculated by the software according to the cast-in-place floor simulation (i.e., the "tension steel bar stress advance phenomenon"), a reasonable theoretical formula is derived to obtain the magnification coefficient of the longitudinal reinforcement area at the bottom of the longitudinal rib beam. The corresponding coefficient can be multiplied during design to carry out reinforcement design, which simplifies the design process and avoids unnecessary waste or safety hazards. The other prefabricated concrete composite components can also refer to this formula to consider the stress advance of the tension steel bars. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1 It is the plan layout of the two-way multi-rib composite slab;

[0048] Figure 2A This is the plane structure diagram of the bidirectional multi-rib precast slab;

[0049] Figure 2B for Figure 2A HH section view;

[0050] Figure 2C for Figure 2A II-direction cross-sectional view;

[0051] Figure 3A It is a structural schematic diagram of a U-shaped frame 31 arranged in the middle rib 3;

[0052] Figure 3B It is a structural schematic diagram of a triangular steel bar truss 32 arranged in the middle rib 3;

[0053] Figure 3C It is a schematic diagram of the structure in which an S-shaped frame 41 is arranged in the side rib 4;

[0054] Figure 3D It is a schematic diagram of the structure in which a plane steel bar truss 42 is arranged in the side rib 4;

[0055] Figure 4A It is a schematic diagram of a case where a U-shaped frame 31 is provided in the middle rib 3 and an S-shaped frame 41 is provided in the side rib 4;

[0056] Figure 4BIt is a schematic diagram of a case where a triangular steel bar truss 32 is arranged in the middle rib 3 and a plane steel bar truss 42 is arranged in the side rib 4;

[0057] Figure 5A is a longitudinal cross-sectional view of the triangular steel bar truss 32;

[0058] Figure 5B is a side view of the triangular steel bar truss 32;

[0059] Figure 5C is a bottom view of the triangular steel bar truss 32;

[0060] Figure 6 It is a structural schematic diagram of a plane steel bar truss 42;

[0061] Fig. 7A It is a structural diagram of the bottom longitudinal reinforcement of the transverse middle rib 3 and the side rib 4 in the post-cast zone 8 when the connecting plate 82 is used for welding;

[0062] Figure 7B It is a structural diagram of the bottom longitudinal reinforcement of the transverse middle rib 3 and the side rib 4 in the post-cast zone 8 when welded or mechanically connected;

[0063] Fig. 8A Detailed drawing of the convex end support beam structure;

[0064] Figure 8B Detailed drawing of the rectangular end support beam construction.

[0065] Among them, 1-bidirectional multi-rib precast slab, 2-bottom plate, 21-bottom plate steel mesh, 3-middle rib, 31-U-shaped frame, 311-bottom reinforcement, 312-U-shaped reinforcement, 32-triangular steel truss, 321-upper chord reinforcement, 322-lower chord reinforcement, 323-vertical web member reinforcement, 324-bottom web member straight reinforcement, 325-bottom web member oblique reinforcement, 4-side rib, 41-S-shaped frame, 411-S-shaped reinforcement, 42-plane steel truss, 421-upper chord flat reinforcement, 422-lower chord flat reinforcement, 423-web member oblique reinforcement, 5-superimposed layer, 51-superimposed steel mesh, 6-end support beam, 7-side support beam, 8-post-cast strip, 81-shear key, 82-connecting plate. DETAILED DESCRIPTION

[0066] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application, that is, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0067] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0068] It should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to the device.

[0069] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0070] See also Figure 1 , Figure 2A , Figure 2B as well as Figure 2C The present application provides an assembled reinforced concrete bidirectional dense-ribbed composite slab floor, which includes a dense-ribbed precast slab 1, a composite layer 5, an end support beam 6, a side support beam 7 and a post-cast strip 8, wherein the side support beam 7 is arranged along the longitudinal direction of the slab and distributed on both sides of the slab, and the end support beam 6 is arranged along the transverse direction of the slab. The end support beam 6, the side support beam 7 and the frame column are spliced ​​to form an installation frame of the bidirectional dense-ribbed precast slab 1. A plurality of bidirectional dense-ribbed precast slabs 1 are arranged in parallel, and the two ends of the bidirectional dense-ribbed precast slab 1 are placed on the two end support beams 6. A post-cast strip 8 is reserved at the joint of the two bidirectional dense-ribbed precast slabs 1, and the composite layer 5 is stacked on the bidirectional dense-ribbed precast slab 1 to form a bidirectional dense-ribbed composite slab floor.

[0071] See also Figure 3A , Figure 3B , Figure 3C , Figure 3D , Figure 4A , Figure 4B , Figure 5A , Figure 5B , Figure 5C as well as Figure 6 The above-mentioned two-way multi-rib precast panel 1 includes a bottom plate 2, a middle rib 3 and a side rib 4; wherein, the thickness of the bottom plate 2 is preferably 40 mm to 60 mm, a single-layer two-way bottom plate steel mesh 21 is arranged in the bottom plate 2, and the top surface of the bottom plate 2 opposite to the laminated layer 5 should be made into an artificial rough surface with a concave-convex depth of not less than 4 mm to ensure the adhesion with the laminated layer 5. Multiple side ribs 4 are overlapped end to end to form the outer frame of the two-way multi-rib precast panel 1, and the middle ribs 3 are cross-distributed horizontally and vertically to divide the inner side of the outer frame formed by the side ribs 4 into multiple bottom plate installation areas, and the bottom plate 2 is embedded in the bottom plate installation area; the middle ribs 3 and the side ribs 4 are convex downwards compared to the bottom plate 2, so that the direction in which the middle ribs 3 and the side ribs 4 convex outwards is opposite to the setting direction of the laminated layer 5.

[0072] Further explanation: the width of the middle rib 3 should not be less than 90 mm, the center distance should be 500 mm to 900 mm, and a U-shaped frame 31 is provided in the middle rib 3. Figure 3A , 4A As shown, the U-shaped frame 31 is composed of bottom reinforcement 311 and U-shaped reinforcement 312. The bottom reinforcement 311 is laid on both sides of the bottom of the U-shaped frame 31 along the length direction of the middle rib 3. The bottom of the U-shaped reinforcement 312 is surrounded by the outside of the two bottom reinforcements 311. The two ends of the U-shaped reinforcement 312 pass through the bottom plate 2 and extend to the laminated layer 5 above the bottom plate 2, connecting the middle rib 3, the bottom plate 2 and the laminated layer 5 from bottom to top, so that the main reinforcement and the concrete in the compression zone work together.

[0073] In order to effectively reduce the amount of steel bar binding, realize automated production and speed up the construction progress, facilitate steel bar positioning, ensure the thickness of the concrete protective layer and improve the bearing and deformation resistance of the structure, the above-mentioned U-shaped skeleton 31 can also be replaced by a triangular steel bar truss 32.

[0074] See also Figure 3B , 4B as well as Figure 5A , 5B , 5C, when a triangular steel truss 32 is provided in the middle rib 3, the triangular steel truss 32 is formed by welding and binding with an upper chord 321, a lower chord 322, a vertical web member 323, a bottom web member straight rib 324 and a bottom web member oblique rib 325 by a special machine, the lower chord 322 is laid on both sides of the bottom of the triangular steel truss 32 along the length direction of the middle rib 3, the upper chord 321 is laid above the lower chord 322 along the length direction of the middle rib 3 and the two lower chords 322 are respectively located at the three vertices of the isosceles triangle, and The vertical web reinforcement 323 crosses the ends of the upper chord reinforcement 321 and extends to the lower chord reinforcement 322 to form a closed isosceles triangle ring, and the upper chord reinforcement 321 extends to the laminated layer 5 above the bottom plate 2. The bottom web straight reinforcement 324 and the bottom web oblique reinforcement 325 are arranged at intervals and connected end to end and laid between the two lower chord reinforcements 322. The bottom web straight reinforcement 324 is vertically connected to the lower chord reinforcement 322, and the bottom web oblique reinforcement 325 is obliquely connected between the two bottom web straight reinforcements 324 and forms an angle of 30 to 45 degrees with the bottom web straight reinforcement 324. The middle rib 3, the bottom plate 2 and the laminated layer 5 are connected from bottom to top as a whole through the triangular steel truss 32.

[0075] Further explanation: the width of the side rib 4 should not be less than 60 mm, the height is the same as the middle rib 3, and it is arranged at the outer periphery of the bidirectional multi-rib precast slab 1. An S-shaped frame 41 or a plane steel truss 42 can be arranged in the side rib 4. The side rib 4 can be used as a lateral formwork between the rib beams when the post-cast concrete superposition layer 5 and the post-cast strip 8 are cast on the support beam of the bidirectional multi-rib precast slab 1, and on the other hand, a shear key 81 is added thereon to increase the bonding surface of the concrete, ensure the continuity of the shear force transmission of the transverse rib beam, and improve the integrity of the bidirectional multi-rib floor.

[0076] See also Figure 3C , 4A When an S-shaped frame 41 is set in the side rib 4, the S-shaped frame 41 is composed of a bottom rib 311 and an S-shaped rib 411. The bottom rib 311 is laid along the length direction of the side rib 4 at the middle position of the bottom of the S-shaped frame 41. The bottom bent end of the S-shaped rib 411 bypasses the bottom rib 311 and is hooked with the bottom rib 311. The other end of the S-shaped rib 411 passes through the bottom plate 2 and extends to the laminated layer 5 above the bottom plate 2, connecting the side rib 4, the bottom plate 2 and the laminated layer 5 from bottom to top.

[0077] See also Figure 3D , 4B as well as Figure 6 When the plane steel bar truss 42 is arranged in the side rib 4, the plane steel bar truss 42 is welded by the upper chord flat bar 421, the lower chord flat bar 422 and the web member diagonal bar 423 through a special machine. The lower chord flat bar 422 is laid at the bottom center of the plane steel bar truss 42 along the length direction of the side rib 4, the upper chord flat bar 421 is laid above the lower chord flat bar 422 along the length direction of the side rib 4, and extends to the laminated layer 5 above the bottom plate 2, and the web member diagonal bar 423 is obliquely connected between the upper chord flat bar 421 and the lower chord flat bar 422, and the inclination angles of the two adjacent web member diagonal bars 423 are opposite, and an angle of 30 to 60 degrees is formed between the two diagonal bars 423.

[0078] To further explain, the thickness of the laminated layer 5 should not be less than 50 mm, and a laminated steel mesh 51 is provided in the laminated layer 5 , and the laminated steel mesh 51 is laid in the laminated layer 5 .

[0079] It should be noted that the integral joint on the side of the bidirectional multi-ribbed prefabricated panel 1 of the present application should be arranged in the secondary force direction of the composite panel and should avoid the maximum bending moment section, see Fig. 7A and 7B A post-cast strip 8 is provided at the joint, and additional steel bars are provided in the post-cast strip 8. The structure of the additional steel bars can be the same as the triangular steel bar truss 32 structure or the plane steel bar truss 42 structure provided in the above-mentioned side rib 4 or middle rib 3, or can be other steel bar structures.

[0080] In order to further strengthen the connection of the post-cast strip 8, grooves are preferably provided on the side ribs 4 on both sides of the post-cast strip 8, and shear keys 81 are formed after pouring non-shrinkage fine stone concrete of one level higher than the superimposed layer 5. The bottom longitudinal reinforcements of the transverse middle rib 3 and the side rib 4 can be welded or mechanically directly connected in the post-cast strip 8, or indirectly connected through the connecting plate 82, that is, connecting plates 82 are respectively provided on both sides of the post-cast strip 8, and the bottom longitudinal reinforcements of the transverse middle rib 3 and the side rib 4 are directly welded to the connecting plate 82 in the factory, and then the connecting plates 8 are welded together on the construction site.

[0081] The connection between the bidirectional multi-ribbed precast slab 1 and the end support beam 6 and the bidirectional multi-ribbed precast slab 1 and the side support beam 7 of the present application can be directly placed on the end support beam 6 or the side support beam 7. Fig. 8A , 8B As shown, the bottom reinforcement 311 at both ends of the middle rib 3, the lower chord reinforcement 322 of the triangular steel truss 32, the bottom reinforcement 311 at both ends of the side rib 4, and the lower chord flat reinforcement 422 of the plane steel truss 42 should be extended to a certain length and anchored in the end support beam 6 or the side support beam 7, and then concrete is poured to cast the superimposed layer 5 and the two-way dense-ribbed precast panel 1 and the top of the end support beam 6 and the side support beam 7 into an integrated structure. In this connection method, the placement length of the middle rib 3 on the end support beam 6 should not be less than 20 mm. It is also possible to set a connecting key at the top of the end support beam 6 while directly placing it to extend it to the gap between the two-way dense-ribbed precast panels 1 and the two-way dense-ribbed precast panels 1 to form a convex beam, and then concrete is poured to cast the superimposed layer 5 and the two-way dense-ribbed precast panel 1 and the top shear key of the end support beam 6 and the side support beam 7 into an integrated structure.

[0082] Since the prefabricated reinforced concrete bidirectional multi-rib composite slab floor of the present application is not supported during the construction stage, it should be considered that the actual initial stress in the longitudinal reinforcement at the bottom of the span of the longitudinal middle rib 3 and the side rib 4 caused by the change of the effective height of the rib beam and the boundary conditions of the support (simply supported or continuous member) during the construction stage (the stage before the concrete of the later poured composite layer 5 reaches the design strength value) and the use stage (the stage after the concrete of the composite layer 5 reaches the design strength value) is greater than the reinforcement stress calculated by the software according to the cast-in-place floor simulation (that is, "the phenomenon of advanced stress of tensile reinforcement"). This advanced stress can be considered by multiplying the area of ​​the longitudinal reinforcement at the bottom of the span of the longitudinal middle rib 3 and the side rib 4 calculated by the software according to the cast-in-place floor simulation during the use stage by the magnification factor. Therefore, the bottom reinforcement 311 of the longitudinal middle rib 3 or the lower chord reinforcement 342 of the triangular steel truss, the bottom reinforcement 311 of the longitudinal side rib 4 or the lower chord flat reinforcement 422 of the plane steel truss s1 for:

[0083] A s1 =A s0 ·η

[0084]

[0085] Among them, A s0 is the bottom longitudinal reinforcement area of ​​the longitudinally arranged middle rib 3 and side rib 4 at the same position calculated as a whole according to the non-assembled cast-in-place floor;

[0086] η is the magnification factor of the longitudinal reinforcement area at the bottom of the longitudinal middle rib 3 and the side rib 4 caused by the leading stress of the steel bars during assembly;

[0087] β is the ratio of the effective height of the prefabricated middle rib of the bidirectional multi-rib prefabricated plate 1 to the effective height of the middle rib after being overlapped;

[0088] α is the ratio of the design value of the self-weight load to the design value of the total load. The self-weight load includes the self-weight of the two-way multi-ribbed precast slab 1 and the self-weight of the superimposed layer 5; the total load includes the self-weight load, the surface layer load and the live load, and is multiplied by the corresponding partial coefficient and the combination value coefficient;

[0089] M 1 It is the design value of the bending moment generated by the self-weight load at the bottom of the mid-span of the longitudinally arranged middle rib 3 and the longitudinally arranged side rib 4 in the construction stage according to the single-span simply supported member; M is the design value of the bending moment generated by the total load at the bottom of the mid-span of the longitudinally arranged middle rib 3 and the longitudinally arranged side rib 4 at the same position.

[0090] When the effective height of the precast middle rib is 165mm, the thickness of the laminated layer is 60mm, and the self-weight design value of the bidirectional multi-rib precast slab 1 is 2.5kN / m 2 , the self-weight of the laminated layer 5 is 1.5kN / m 2 , surface load is 2.0kN / m 2 , live load is 5.0kN / m 2 , design value of bending moment M 1 The structural calculation software YJK is used to model and calculate the T-shaped hollow slab floor, and the design value of the bending moment at the bottom of the 3-span middle rib is 38 kN m, and the longitudinal reinforcement area A at the bottom of the 3-span middle rib is s0 534mm 2 , the magnification coefficient η is determined to be 1.8, and then the bottom reinforcement 311 of the longitudinally arranged middle rib 3 or the lower chord reinforcement 342 of the triangular steel truss, the bottom reinforcement 311 of the longitudinally arranged side rib 4 and the area A of the lower chord flat reinforcement 422 of the plane steel truss are determined. s1 961mm 2 .

[0091] The construction method of the above-mentioned assembled reinforced concrete bidirectional multi-ribbed composite slab floor comprises the following steps:

[0092] 1) In the factory, first place the bottom plate 2, middle rib 3 and side rib 4 steel bars in the mold and tie them up, and preset grooves on the side rib 4 molds on both sides, pour concrete at the middle rib 3 and side rib 4, vibrate, and then pour concrete at the bottom plate 2 and vibrate. Specifically:

[0093] 1.1) The magnification factor of the longitudinal reinforcement area at the bottom of the longitudinal middle rib 3 and the side rib 4 caused by the leading stress of the steel bars is calculated by the following formula:

[0094] 1.2) Determine the area A of the bottom reinforcement 311 of the longitudinal middle rib 3 or the lower chord reinforcement 342 of the triangular steel truss, the bottom reinforcement 311 of the longitudinal side rib 4 or the lower chord flat reinforcement 422 of the plane steel truss s1 ;

[0095] 1.3) Bottom longitudinal reinforcement area A of longitudinal middle rib 3 and side rib 4 s1 Determine the diameter and quantity of steel bars;

[0096] 1.4) According to the conventional design results of the floor slab and the diameter and number of the bottom longitudinal reinforcement of the longitudinal middle rib 3 and the side rib 4, in the factory, the bottom plate 2, the middle rib 3 and the side rib 4 reinforcement are first placed in the mold and tied, and grooves are preset on the molds of the side ribs 4 on both sides. Concrete is poured at the middle rib 3 and the side rib 4, and after vibrating, concrete is poured at the bottom plate 2 and vibrated.

[0097] 2) The top surface of the concrete of the bottom plate 2 is roughened, and after curing and demoulding, the bidirectional multi-ribbed precast plate 1 can be produced;

[0098] 3) After the end support beam 6 and the side support beam 7 are constructed, the bidirectional multi-rib precast slab 1 is hoisted into place, with both ends placed on the end support beam 6;

[0099] 4) A post-cast strip 8 is reserved at the joint of adjacent bidirectional multi-rib precast panels 1, additional steel bars are arranged in the post-cast strip 8, the bottom longitudinal bars of the transverse middle rib 3 and the side rib 4 in the post-cast strip are welded or mechanically connected, or the connecting plates 82 on both sides of the post-cast strip 8 are welded together, and a bottom mold is arranged at the bottom of the post-cast strip 8 as needed;

[0100] 5) A steel mesh 51 is arranged in the composite layer 5, and the bidirectional multi-ribbed precast slab 1 is used as a permanent bottom form to cast and maintain the concrete of the composite layer 5, thereby completing the construction of the assembled reinforced concrete bidirectional multi-ribbed composite slab floor.

[0101] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An assembled reinforced concrete bidirectional multi-ribbed composite slab floor, characterized in that: The invention comprises a bidirectional dense-ribbed precast slab (1), a laminated layer (5), an end support beam (6), a side support beam (7) and a post-cast strip (8); the end support beam (6), the side support beam (7) and the frame column are spliced ​​to form an installation frame of the bidirectional dense-ribbed precast slab (1); both ends of the bidirectional dense-ribbed precast slab (1) are placed on the end support beam (6); the post-cast strip (8) is arranged at the joint of two bidirectional dense-ribbed precast slabs (1); the laminated layer (5) is stacked on the top of the bidirectional dense-ribbed precast slab (1) to form a bidirectional dense-ribbed laminated slab floor; the thickness of the laminated layer (5) is not less than 50 mm; The bidirectional multi-rib precast plate (1) comprises a bottom plate (2), a middle rib (3) and side ribs (4); a plurality of the side ribs (4) are overlapped end to end to form an outer frame of the bidirectional multi-rib precast plate (1); the middle ribs (3) are cross-distributed transversely and longitudinally to divide the inner side of the outer frame formed by the side ribs (4) into a plurality of bottom plate installation areas, and the bottom plate (2) is embedded in the bottom plate installation areas; the middle ribs (3) and the side ribs (4) protrude downwardly relative to the bottom plate (2), so that the direction in which the middle ribs (3) and the side ribs (4) protrude outwards is opposite to the setting direction of the laminated layer (5); the longitudinal cross-sectional area A of the longitudinally arranged bottom reinforcement (311) of the middle rib (3) or the lower chord reinforcement (342) of the triangular steel truss, and the longitudinally arranged bottom reinforcement (311) of the side ribs (4) or the lower chord flat reinforcement (422) of the plane steel truss s1 Both are: A s1 =A s0 ·or Among them, A s0 is the bottom longitudinal reinforcement area of ​​the longitudinally arranged middle rib (3) and side rib (4) at the same position calculated as a whole according to the non-assembled cast-in-place floor; η is the magnification factor of the bottom longitudinal reinforcement area of ​​the longitudinally arranged middle rib (3) and side rib (4) caused by the leading stress of the reinforcement during assembly; β is the ratio of the effective height of the prefabricated middle rib of the bidirectional multi-rib prefabricated plate (1) to the effective height of the middle rib after being overlapped; α is the ratio of the design value of the self-weight load to the design value of the total load, the self-weight load includes the self-weight of the bidirectional multi-ribbed precast slab (1) and the self-weight of the superimposed layer (5); the total load includes the self-weight load, the surface layer load and the live load, and is multiplied by the corresponding partial coefficient and the combination value coefficient; M1 is the design value of the bending moment generated by the self-weight load at the bottom of the mid-span of the longitudinally arranged middle rib (3) and the longitudinally arranged side rib (4) in the construction stage as a single-span simply supported member; M is the design value of the bending moment generated by the total load at the bottom of the mid-span of the longitudinally arranged middle rib (3) and the longitudinally arranged side rib (4) at the same position.

2. The assembled reinforced concrete bidirectional multi-ribbed composite slab floor according to claim 1 is characterized in that: A U-shaped frame (31) composed of bottom ribs (311) and U-shaped ribs (312) or a triangular steel truss (32) is arranged in the middle rib (3); the top end of the U-shaped frame (31) or the triangular steel truss (32) passes through the bottom plate (2) and extends into the laminated layer (5), and the bottom end extends to the bottom of the middle rib (3).

3. The assembled reinforced concrete bidirectional multi-ribbed composite slab floor according to claim 2 is characterized in that: The triangular steel bar truss (32) comprises an upper chord (321), a lower chord (322), a vertical web member (323), a bottom web member straight reinforcement (324) and a bottom web member oblique reinforcement (325), wherein the lower chord (322) is laid on both sides of the bottom of the triangular steel bar truss (32) along the length direction of the middle rib (3), the upper chord (321) is laid above the lower chord (322) along the length direction of the middle rib (3) and is respectively located at the three vertices of an isosceles triangle with the two lower chords (322), and the vertical web member (323) crosses the upper chord (32 1) Both sides extend to the lower chord (322) to form a closed isosceles triangle ring, and the upper chord (321) extends to the laminated layer (5) above the bottom plate (2), and the bottom web bar straight reinforcement (324) and the bottom web bar oblique reinforcement (325) are arranged at intervals and connected end to end and laid between the two lower chords (322); the bottom web bar straight reinforcement (324) is vertically connected to the lower chord (322), and the bottom web bar oblique reinforcement (325) is obliquely connected between the two bottom web bar straight reinforcements (324) and forms an angle of 30 to 45 degrees with the bottom web bar straight reinforcement (324).

4. The assembled reinforced concrete bidirectional multi-ribbed composite slab floor according to claim 2 is characterized in that: An S-shaped frame (41) or a flat steel bar truss (42) is provided in the side rib (4); the top end of the S-shaped frame (41) or the flat steel bar truss (42) passes through the bottom plate (2) and extends into the laminated layer (5), and the bottom end extends to the bottom of the side rib (4); The plane steel bar truss (42) comprises an upper chord flat bar (421), a lower chord flat bar (422) and a web member diagonal bar (423); the lower chord flat bar (422) is laid at the bottom center position of the plane steel bar truss (42) along the length direction of the side rib (4); the upper chord flat bar (421) is laid above the lower chord flat bar (422) along the length direction of the middle rib (3) and extends into the laminated layer (5) above the bottom plate (2); the web member diagonal bar (423) is obliquely connected between the upper chord flat bar (421) and the lower chord flat bar (422); and the inclination angles of two adjacent web member diagonal bars (423) are opposite, forming an angle of 30 to 60 degrees between the two.

5. The assembled reinforced concrete bidirectional multi-ribbed composite slab floor according to claim 1, characterized in that: The integral joint on the side of the bidirectional dense-ribbed precast slab (1) is arranged in the secondary force direction of the composite slab and avoids the maximum bending moment section, the post-cast strip (8) is arranged at the joint of the bidirectional dense-ribbed precast slab (1), and additional steel bars are arranged in the post-cast strip (8).

6. The assembled reinforced concrete bidirectional multi-ribbed composite slab floor according to claim 1, characterized in that: Grooves are arranged on the adjacent side ribs (4) of the post-cast strip (8), and shear keys (81) are formed after pouring non-shrinkage fine stone concrete.

7. The assembled reinforced concrete bidirectional multi-ribbed composite slab floor according to claim 6, characterized in that: The bottom longitudinal reinforcements of the transverse middle rib (3) and the side rib (4) are directly connected in the post-cast strip (8) or indirectly connected via a connecting plate (82).

8. The construction method of the assembled reinforced concrete bidirectional multi-ribbed composite slab floor according to claim 1, characterized in that: The steps include: 1) In the factory, firstly, the bottom plate (2), the middle rib (3) and the side rib (4) steel bars are placed in the mold and tied, and grooves are preset on the molds of the side ribs (4) on both sides, and concrete is poured at the middle rib (3) and the side ribs (4), and vibrated, and then concrete is poured at the bottom plate (2) and vibrated; 2) roughening the top surface of the concrete of the bottom plate (2), and after curing and demoulding, the bidirectional multi-ribbed precast plate (1) can be produced; 3) After the end support beam (6) and the side support beam (7) are constructed, the bidirectional multi-rib precast slab (1) is hoisted into place, with both ends placed on the end support beam (6); 4) A post-cast strip (8) is reserved at the joint of adjacent bidirectional multi-rib precast panels (1), additional steel bars are arranged in the post-cast strip (8), the bottom longitudinal bars of the transverse middle rib (3) and the side rib (4) in the post-cast strip are welded or mechanically connected, or the connecting plates (82) on both sides of the post-cast strip (8) are welded together, and a bottom mold is arranged at the bottom of the post-cast strip (8) as needed; 5) A steel mesh (51) is arranged in the laminated layer (5), and the bidirectional multi-ribbed precast slab (1) is used as a permanent bottom form to cast and maintain the concrete of the laminated layer (5), thereby completing the construction of the assembled reinforced concrete bidirectional multi-ribbed laminated slab floor.

9. The construction method of the assembled reinforced concrete bidirectional multi-ribbed composite slab floor according to claim 8, characterized in that: The step 1) is: 1.1) The magnification factor of the longitudinal reinforcement area at the bottom of the longitudinal middle rib (3) and the side rib (4) caused by the leading stress of the reinforcement is calculated by the following formula: in, β is the ratio of the effective height of the prefabricated middle rib of the bidirectional multi-rib prefabricated plate (1) to the effective height of the middle rib after being overlapped; α is the ratio of the design value of the self-weight load to the design value of the total load, the self-weight load includes the self-weight of the bidirectional multi-ribbed precast slab (1) and the self-weight of the superimposed layer (5); the total load includes the self-weight load, the surface layer load and the live load, and is multiplied by the corresponding partial coefficient and the combination value coefficient; M1 is the design value of the bending moment generated by the self-weight load at the bottom of the mid-span of the longitudinally arranged middle rib (3) and the longitudinally arranged side rib (4) in the construction stage as a single-span simply supported member; M is the design value of the bending moment generated by the total load at the bottom of the mid-span of the longitudinally arranged middle rib (3) and the longitudinally arranged side rib (4) at the same position; 1.2) Determine the longitudinal cross-sectional area A of the longitudinally arranged middle rib (3) bottom reinforcement (311) or the triangular steel truss lower chord reinforcement (342), the longitudinally arranged side rib (4) bottom reinforcement (311) or the plane steel truss lower chord flat reinforcement (422) s1 Both are: A s1 =A s0 ·or Among them, A s0 is the bottom longitudinal reinforcement area of ​​the longitudinally arranged middle rib (3) and side rib (4) at the same position calculated as a whole according to the non-assembled cast-in-place floor; η is the magnification factor of the bottom longitudinal reinforcement area of ​​the longitudinal middle rib (3) and the side rib (4) caused by the leading stress of the reinforcement during assembly; 1.3) According to the bottom longitudinal reinforcement area A of the longitudinally arranged middle rib (3) and side rib (4): s1 Determine the diameter and quantity of steel bars; 1.4) According to the conventional design results of the floor slab and the diameter and number of the bottom longitudinal reinforcement of the longitudinal middle rib (3) and the side rib (4), in the factory, the bottom plate (2), the middle rib (3) and the side rib (4) reinforcement are first placed in the mold and tied, and recesses are preset on the molds of the side ribs (4) on both sides. Concrete is poured at the middle rib (3) and the side rib (4) and vibrated. Then, concrete is poured at the bottom plate (2) and vibrated.

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