CN113152761A

CN113152761A - Assembled reinforced concrete bidirectional ribbed laminated slab floor and construction method thereof

Info

Publication number: CN113152761A
Application number: CN202110340204.XA
Authority: CN
Inventors: 陶倍林; 贾俊明; 吴琨; 刘锋; 吴翔艳
Original assignee: China Northwest Architecture Design and Research Institute Co Ltd
Current assignee: China Northwest Architecture Design and Research Institute Co Ltd
Priority date: 2021-03-30
Filing date: 2021-03-30
Publication date: 2021-07-23

Abstract

The invention belongs to the technical field of building design, and particularly relates to an assembled reinforced concrete bidirectional multi-ribbed composite slab floor and a construction method thereof, wherein the assembled reinforced concrete bidirectional multi-ribbed composite slab floor comprises a bidirectional multi-ribbed precast slab, a superposed layer, an end support beam, a side support beam and a post-cast strip, the end support beam, the side support beam and a frame column are spliced to form an installation frame of the bidirectional multi-ribbed precast slab, two ends of the bidirectional multi-ribbed precast slab are placed on the end support beam, and the bidirectional multi-ribbed precast slab comprises a bottom plate, a middle rib and a side rib; the middle ribs and the side ribs are protruded downwards than the bottom plate, so that the outward protruding direction of the middle ribs and the side ribs is opposite to the arrangement direction of the overlapped layer; the invention realizes the assembly of the reinforced concrete bidirectional dense rib floor, has the advantages of both the laminated slab and the bidirectional dense rib plate, and has the advantages of less field wet operation, good component quality, template and manpower saving, simple construction, short construction period and the like; the floor slab has the advantages of uniform force transmission, reasonable stress, small structural height, light dead weight, high rigidity and good earthquake resistance.

Description

Assembled reinforced concrete bidirectional ribbed laminated slab floor and construction method thereof

Technical Field

The invention belongs to the technical field of building design, and particularly relates to an assembled reinforced concrete bidirectional multi-ribbed composite slab floor and a construction method thereof.

Background

The cast-in-place reinforced concrete bidirectional ribbed floor is widely applied to public buildings such as malls, exhibition centers, parking lots, teaching buildings and the like and large-compartment houses at present. Compared with the common beam slab floor, the bidirectional multi-ribbed floor has the advantages of more reasonable stress, light dead weight, high rigidity, good integrity, material saving, high construction speed, space saving, floor height reduction and the like, but also has the defects of large on-site reinforcement binding amount, high special cost for purchasing, leasing, installing and disassembling the membrane shell, low assembly rate and the like, and a formwork is required to be erected at the bottom.

With the vigorous popularization of the prefabricated building in China, the reinforced concrete floor system is taken as an important component of the prefabricated building, and the influence on the assembly rate is particularly great. The existing commonly used assembled floor is a steel bar truss laminated slab, and has the advantages of reducing building frames and templates, saving labor, accelerating construction speed, reducing field wet operation, saving construction cost and the like.

In addition, during calculation of the laminated slab, a cast-in-place floor slab is often used for modeling design, stress changes of the laminated slab caused by changes of the height of a compression zone and boundary conditions in a construction stage and a use stage cannot be simulated, namely the phenomenon of stress advance of a tension steel bar cannot be considered, and particularly when the self-weight load is large, potential safety hazards are caused due to small calculation results.

Disclosure of Invention

In order to overcome the technical problems of the existing steel bar truss laminated slab, the invention provides an assembly type reinforced concrete bidirectional multi-ribbed laminated slab floor which is formed by making a common laminated slab into a bidirectional multi-ribbed laminated slab floor consisting of thin plates and plate ribs with smaller intervals, has the dual advantages of the bidirectional multi-ribbed floor and the laminated floor, and has the advantages of light dead weight, high rigidity, low material and labor cost, high assembly rate, high construction speed and the like.

The technical scheme adopted by the invention is as follows:

an assembled reinforced concrete two-way multi-ribbed composite slab floor comprises two-way multi-ribbed precast slabs, superposed layers, end support beams, side support beams and post-cast strips, wherein the end support beams, the side support beams and frame columns are spliced to form an installation frame of the two-way multi-ribbed precast slabs, two ends of each two-way multi-ribbed precast slab are placed on the end support beams, the post-cast strips are arranged at the joints of the two-way multi-ribbed precast slabs, and the superposed layers are stacked above the two-way multi-ribbed precast slabs to form the two-way multi-ribbed composite slab floor;

the bidirectional ribbed precast slab comprises a bottom plate, a middle rib and side ribs; the plurality of edge ribs are overlapped end to form an outer frame of the bidirectional multi-ribbed precast slab, the middle ribs are transversely and longitudinally distributed in a crossed manner to divide the inner side of the outer frame formed by the edge ribs into a plurality of bottom plate mounting areas, and the bottom plates are embedded in the bottom plate mounting areas; the middle ribs and the side ribs are protruded downwards than the bottom plate, so that the outward protruding direction of the middle ribs and the side ribs is opposite to the arrangement direction of the overlapped layer.

Further limiting, the longitudinal section area A of the middle rib bottom rib or the lower chord rib of the triangular steel bar truss which is longitudinally arranged, the side rib bottom rib which is longitudinally arranged or the lower chord flat rib of the plane steel bar truss_s1All are as follows:

A_s1＝A_s0·η

wherein A is_s0The area of the bottom longitudinal ribs of the middle rib and the side rib which are longitudinally distributed at the same position is obtained by integral calculation according to the non-assembly type cast-in-place floor system;

eta is the amplification coefficient of the areas of the longitudinal middle ribs and the longitudinal ribs at the bottoms of the side ribs caused by the stress advance of the steel bars during assembly;

beta is the ratio of the effective height of the prefabricated middle rib of the bidirectional multi-ribbed precast slab to the effective height of the superposed middle rib;

alpha is the ratio of the designed value of the dead weight load to the designed value of the total load, and the dead weight load comprises the dead weight of the bidirectional multi-ribbed precast slab and the dead weight of the superposed layer; the total load comprises a dead load, a surface layer load and a live load, and is multiplied by a corresponding subentry coefficient and a corresponding combination value coefficient;

M₁the design value of bending moment generated by dead load at the middle rib longitudinally arranged and the middle bottom of the side rib span longitudinally arranged is considered for a construction stage according to a single-span simple support component; m is a bending moment design value generated by the middle bottom of the longitudinally arranged middle rib and the longitudinally arranged side rib at the same position of the total load.

Further limiting, a U-shaped framework consisting of a bottom rib and a U-shaped rib or a triangular steel bar truss is arranged in the middle rib; the top end of the U-shaped framework or the triangular steel bar truss penetrates through the bottom plate and extends into the superposed layer, and the bottom end of the U-shaped framework or the triangular steel bar truss extends to the bottom of the middle rib.

Further limiting, the triangular steel bar truss comprises upper chord bars, lower chord bars, vertical web bar bars, bottom web bar straight bars and bottom web bar diagonal bars, the lower chord bars are laid on two sides of the bottom of the triangular steel bar truss along the length direction of the middle rib, the upper chord bars are laid above the lower chord bars along the length direction of the middle rib and are respectively positioned at three top points of an isosceles triangle with the two lower chord bars, the vertical web bar bars span across two sides of the upper chord bars and respectively extend to the lower chord bars to form a closed isosceles triangle ring, the upper chord bars extend into a superposed layer above the bottom plate, and the bottom web bar straight bars and the bottom web bar diagonal bars are distributed at intervals and are laid between the two lower chord bars in an end-to-end connection manner; the straight ribs of the bottom web rod are vertically connected with the lower chord ribs, and the inclined ribs of the bottom web rod are obliquely connected between the two straight ribs of the bottom web rod and form an included angle of 30-45 degrees with the straight ribs of the bottom web rod.

Further limiting, an S-shaped framework or a plane steel bar truss is arranged in each edge rib; the top end of the S-shaped framework or the plane steel bar truss penetrates through the bottom plate and extends into the laminated layer, and the bottom end of the S-shaped framework or the plane steel bar truss extends to the bottom of the side rib;

the planar steel bar truss comprises an upper chord flat bar, a lower chord flat bar and a web member inclined bar; the lower chord flat rib is laid at the center of the bottom of the plane steel bar truss along the length direction of the side rib, the upper chord flat rib is laid above the lower chord flat rib along the length direction of the middle rib and extends into the laminated layer above the bottom plate, the web member diagonal ribs are obliquely connected between the upper chord flat rib and the lower chord flat rib, the inclination angles of the two adjacent web member diagonal ribs are opposite, and an included angle of 30-60 degrees is formed between every two adjacent web member diagonal ribs.

Further, the integral joint of the two-way ribbed precast slab side is arranged in the secondary stress direction of the laminated slab and avoids the maximum bending moment section, the post-cast strip is arranged at the joint of the two-way ribbed precast slab, and the additional steel bar is arranged in the post-cast strip.

And further limiting, grooves are formed in the side ribs on two adjacent sides of the post-cast strip, and the shear key is formed after non-shrinkage fine aggregate concrete is poured.

Further, the transverse middle rib and the bottom longitudinal rib of the side rib are directly connected in the post-cast strip or indirectly connected through a connecting plate.

The construction method of the assembled reinforced concrete bidirectional multi-ribbed composite slab floor comprises the following steps:

1) in a factory, firstly, a bottom plate, a middle rib and side rib steel bars are placed in a mould and tied, grooves are preset on the side rib moulds at two sides, concrete at the middle rib and the side ribs is poured, the concrete is vibrated, and then the concrete at the bottom plate is poured and vibrated;

2) carrying out rough treatment on the top surface of the concrete of the bottom plate, and producing the bidirectional multi-ribbed precast slab after curing and demolding;

3) after the end support beam and the side support beam are constructed, hoisting the bidirectional multi-ribbed precast slab in place, and placing two ends of the bidirectional multi-ribbed precast slab on the end support beam;

4) reserving a post-cast strip at the abutted seam of the adjacent bidirectional multi-ribbed precast slabs, arranging additional steel bars in the post-cast strip, welding or mechanically connecting bottom longitudinal bars of a transverse middle rib and side ribs in the post-cast strip or welding connecting plates on two sides of the post-cast strip together, and arranging a bottom die at the bottom of the post-cast strip according to requirements;

5) and arranging a reinforcing mesh in the laminated layer, pouring the laminated layer concrete by taking the bidirectional multi-ribbed precast slab as a permanent bottom die, and curing to finish the construction of the assembled reinforced concrete bidirectional multi-ribbed laminated slab floor.

Further limited, the step 1) is as follows:

1.1) calculating the amplification factor of the areas of the longitudinal ribs at the bottoms of the longitudinal middle rib 3 and the side rib 4 caused by the stress lead of the reinforcing steel bars through the following formula,

wherein beta is the ratio of the effective height of the prefabricated middle rib of the bidirectional multi-ribbed precast slab to the effective height of the superposed middle rib;

M₁the design value of bending moment generated by dead load at the middle rib longitudinally arranged and the middle bottom of the side rib span longitudinally arranged is considered for a construction stage according to a single-span simple support component; m is a bending moment design value generated at the bottom of the middle rib and the side rib span longitudinally arranged at the same position of the total load;

1.2) determining the longitudinal section area A of the middle rib bottom rib or the lower chord rib of the triangular steel bar truss which is longitudinally arranged, the edge rib bottom rib which is longitudinally arranged or the lower chord flat rib of the plane steel bar truss_s1All are as follows:

A_s1＝A_s0·η

wherein A is_s0Longitudinally arranged at the same position and calculated according to the whole of the non-assembled cast-in-place floor systemThe area of the bottom longitudinal ribs of the middle rib and the side ribs;

1.3) area A of longitudinal ribs at the bottom of longitudinally arranged middle ribs and side ribs_s1Determining the diameter and the number of the steel bars;

1.4) according to the conventional design result of the floor system and the diameter and the number of the longitudinal ribs at the bottoms of the longitudinal middle ribs and the side ribs, firstly, placing the bottom plate, the middle ribs and the side rib steel bars in a mould and binding the bottom plate, the middle ribs and the side rib steel bars in a factory, presetting grooves on the side rib moulds at two sides, pouring concrete at the middle ribs and the side ribs, finishing vibration, pouring the concrete at the bottom plate and vibrating.

Compared with the prior art, the invention has the beneficial effects that:

1) the invention realizes the assembly of the reinforced concrete bidirectional dense rib floor, has the advantages of both the laminated slab and the bidirectional dense rib plate, and has the advantages of less field wet operation, good component quality, template and manpower saving, simple construction, short construction period and the like; on the other hand, the bidirectional dense-rib floor has the advantages of uniform force transmission, reasonable stress, small structural height, light dead weight, large rigidity, small deformation, good earthquake resistance and the like.

2) The invention solves the problems of insufficient rigidity, heavier self weight and the like of the large-span steel bar truss composite slab, particularly the large-span large-load structure and the smaller size of the main beam and the rib beam increase the clear height of the building in use, and the temporary support is not required to be additionally arranged during construction, so that the requirements of the prefabricated part on the bearing capacity and the deformation of the composite slab in the construction stage and the use stage can be met, the construction process is simplified, and the construction progress is accelerated.

3) The invention arranges the U-shaped framework or the triangular steel bar truss in the middle rib, arranges the S-shaped framework or the plane steel bar truss in the side rib, can give full play to the advantages of the U-shaped framework, the triangular steel bar truss, the S-shaped framework and the plane steel bar truss, effectively reduces the steel bar binding amount, realizes automatic production, accelerates the construction progress, facilitates the positioning of the steel bars, ensures the thickness of a concrete protective layer and improves the bearing and anti-deformation capability of the structure, and the arrangement of the side rib can be used as a lateral template between the rib beams when a concrete superposed layer and a post-cast strip are cast on a support beam of the bidirectional dense rib precast slab on one hand, and can increase the joint surface of the concrete on the other hand, ensure the continuity of the vertical shear force transmission of the transverse rib beam and improve the integrity of the bidirectional dense rib floor.

4) The invention changes the traditional rough envelope design method of the laminated slab, and reasonably deduces a theoretical formula according to the fact that the actual initial stress in the longitudinal rib at the bottom of the rib beam span middle part caused by the change of the effective height of the rib beam and the boundary condition of the support in the construction stage and the use stage of the dead weight load is greater than the stress of the steel bar calculated by software according to the simulation of the cast-in-place floor (namely the phenomenon of leading the stress of the pulled steel bar), so that the amplification coefficient of the area of the longitudinal rib at the bottom of the longitudinal rib beam is obtained, the design can be multiplied by the corresponding coefficient to carry out the reinforcement allocation design, the design process is simplified, the unnecessary waste or the potential safety hazard is avoided, and the stress leading of the pulled steel bar can be considered by referring to the formula by other assembled concrete laminated members.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

Fig. 1 is a plan view of a bi-directional ribbed laminated plate.

Fig. 2 is a structural view of a bi-directional multi-ribbed precast slab (in which fig. 2A is a plan structural view of the bi-directional multi-ribbed precast slab and fig. 2B is a sectional view taken along the direction H-H of fig. 2A).

Fig. 3 is an installation cross-sectional view of the center rib 3 and the side ribs 4 in fig. 2 (where fig. 3A is a schematic structural view of the U-shaped framework 31 provided in the center rib 3, fig. 3B is a schematic structural view of the triangular steel bar truss 32 provided in the center rib 3, fig. 3C is a schematic structural view of the S-shaped framework 41 provided in the side ribs 4, and fig. 3D is a schematic structural view of the planar steel bar truss 42 provided in the side ribs 4).

Fig. 4 is a reinforcement diagram corresponding to fig. 3 (fig. 4A is a schematic diagram of a case where a U-shaped framework 31 is provided in the center rib 3 and an S-shaped framework 41 is provided in the side rib 4, and fig. 4B is a schematic diagram of a case where a triangular steel truss 32 is provided in the center rib 3 and a planar steel truss 42 is provided in the side rib 4).

Fig. 5 is a schematic structural view of the triangular steel bar truss 32 (in the drawing, 5A is a longitudinal sectional view; 5B is a side view, and 5C is a bottom view).

Fig. 6 is a schematic structural view of the planar steel truss 42.

Fig. 7 is a detailed view of the joint structure of the double multi-ribbed composite slab (fig. 7A is a structural view when the transverse middle rib 3 and the bottom longitudinal rib of the side rib 4 in the post-cast strip 8 are welded by the connecting plate 82, and fig. 7B is a structural view when the transverse middle rib 3 and the bottom longitudinal rib of the side rib 4 in the post-cast strip 8 are welded or mechanically connected).

Fig. 8 is a detailed view of the construction of the double ribbed laminated plate end mount and end mount beam 6 (where fig. 8A is a detailed view of a convex end mount beam construction and fig. 8B is a detailed view of a rectangular end mount beam construction).

The prefabricated slab comprises a 1-bidirectional multi-ribbed prefabricated slab, a 2-base slab, a 21-base slab steel bar mesh, a 3-middle rib, a 31-U-shaped framework, a 311-bottom rib, a 312-U-shaped rib, a 32-triangular steel bar truss, a 321-upper chord rib, a 322-lower chord rib, a 323-vertical web bar rib, a 324-bottom web bar straight rib, a 325-bottom web bar inclined rib, a 4-side rib, a 41-S-shaped framework, a 411-S-shaped rib, a 42-plane steel bar truss, a 421-upper chord flat rib, a 422-lower chord flat rib, a 423-web bar inclined rib, a 5-laminated layer, a 51-laminated mesh steel bar, a 6-end support beam, a 7-side support beam, an 8-post-pouring belt, an 81-shear key and a 82-connecting plate.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the application, i.e., the embodiments described are only a subset of, and not all embodiments of the application. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present application without making any creative effort, shall fall within the protection scope of the present application.

It is to be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a device comprising a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such device.

The features and properties of the present application are described in further detail below with reference to examples.

Referring to fig. 1 and 2, the application provides an assembly type reinforced concrete two-way multi-ribbed composite slab floor, which comprises multi-ribbed precast slabs 1, a laminated layer 5, end support beams 6, side support beams 7 and a post-cast strip 8, wherein the side support beams 7 are arranged along the longitudinal direction of the floor and are distributed at two sides of the floor, the end support beams 6 are arranged along the transverse direction of the floor, the end support beams 6, the side support beams 7 and frame columns are spliced to form an installation frame of the two-way multi-ribbed precast slabs 1, the two-way multi-ribbed precast slabs 1 are arranged in parallel, two ends of each two-way multi-ribbed precast slab 1 are placed on every two end support beams 6, the post-cast strip 8 is reserved at the joint of the two-way multi-ribbed precast slabs 1, and the laminated layer 5 is arranged on the two-way multi-ribbed precast slabs 1 in a stacking manner to form the two-way multi-ribbed precast slabs.

Referring to fig. 3-6, the bidirectional multi-ribbed precast slab 1 comprises a bottom plate 2, a middle rib 3 and side ribs 4; wherein, the thickness of the bottom plate 2 is preferably 40 mm-60 mm, a single-layer bidirectional bottom plate reinforcing mesh 21 is arranged in the bottom plate 2, and the top surface of the bottom plate 2 opposite to the superposed layer 5 is made into an artificial rough surface with the concave-convex depth not less than 4mm, so as to ensure the caking property with the superposed layer 5. The plurality of side ribs 4 are lapped end to form an outer frame of the bidirectional multi-ribbed precast slab 1, the middle ribs 3 are transversely and longitudinally distributed in a crossed manner to divide the inner side of the outer frame formed by the side ribs 4 into a plurality of bottom plate mounting areas, and the bottom plate 2 is embedded in the bottom plate mounting areas; the middle rib 3 and the side rib 4 are protruded downward from the bottom plate 2 such that the direction in which the middle rib 3 and the side rib 4 are protruded outward is opposite to the arrangement direction of the lamination layer 5.

Further, the width of the middle rib 3 is not smaller than 90mm, the center distance is preferably 500 mm-900 mm, a U-shaped framework 31 is arranged in the middle rib 3, as shown in fig. 3A and 4A, the U-shaped framework 31 is composed of bottom ribs 311 and U-shaped ribs 312, the bottom ribs 311 are laid on two sides of the bottom of the U-shaped framework 31 along the length direction of the middle rib 3, the bottoms of the U-shaped ribs 312 surround the outer sides of the two bottom ribs 311, two ends of the U-shaped ribs 312 penetrate through the bottom plate 2 and extend into the laminated layer 5 above the bottom plate 2, the middle rib 3, the bottom plate 2 and the laminated layer 5 are connected into a whole from bottom to top, and the stressed main rib and the concrete in the stressed area work together.

In order to effectively reduce the steel bar binding amount, realize automatic production and accelerate the construction progress, make things convenient for the steel bar location, ensure concrete protective layer thickness and improve the bearing and the anti deformability of structure, above-mentioned U-shaped skeleton 31 can also be replaced by with triangle steel bar truss 32.

Referring to fig. 3B and 4B and fig. 5, when the triangular steel bar truss 32 is disposed in the middle rib 3, the triangular steel bar truss 32 is formed by welding and binding an upper chord bar 321, a lower chord bar 322, a vertical web bar 323, a bottom web bar straight bar 324 and a bottom web bar diagonal bar 325 by a special machine, the lower chord bar 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 bar 321 is laid above the lower chord bar 322 along the length direction of the middle rib 3 and is respectively located at three vertexes of an isosceles triangle with the two lower chord bars 322, the vertical web bar 323 extends across both ends of the upper chord bar 321 to the lower chord bars 322 to form a closed isosceles triangle ring, the upper chord bar 321 extends into the laminated layer 5 above the bottom plate 2, the bottom web bar straight bar 324 and the bottom web bar diagonal bar 325 are spaced and are connected end to end between the two lower chord bars 322, and the bottom web bar straight bar 324 is vertically connected to the lower chord bars 322, the bottom web rod inclined rib 325 is obliquely connected between the two bottom web rod straight ribs 324 and forms an included angle of 30-45 degrees with the bottom web rod straight ribs 324. The middle rib 3, the bottom plate 2 and the laminated layer 5 are connected into a whole from bottom to top through a triangular steel bar truss 32.

Further, the width of the side rib 4 is not preferably less than 60mm, and the height is the same as the height of the center rib 3, and the side rib is arranged on the outer periphery of the bi-directional multi-ribbed precast slab 1. The rib 4 may be provided with an S-shaped frame 41 or a planar steel truss 42. The side ribs 4 have the functions of serving as lateral templates between the rib beams when the concrete laminated layer 5 and the post-cast strip 8 are cast on the support beam of the bidirectional multi-ribbed precast slab 1 on one hand, and adding the shear keys 81 on the other hand, so that the joint surface of concrete can be increased, the continuity of shear force transmission of the transverse rib beam is ensured, and the integrity of the bidirectional multi-ribbed floor is improved.

Referring to fig. 3C and 4A, when the S-shaped frame 41 is disposed 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 at the middle position of the bottom of the S-shaped frame 41 along the length direction of the side rib 4, the bent end of the bottom 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 into the overlapping layer 5 above the bottom plate 2, and the side rib 4, the bottom plate 2 and the overlapping layer 5 are connected into a whole from bottom to top.

Referring to fig. 3D and 4B and fig. 6, when the planar steel bar truss 42 is disposed in the side rib 4, the planar steel bar truss 42 is formed by welding the upper chord flat bar 421, the lower chord flat bar 422 and the web member diagonal bar 423 by a special machine. The lower chord flat rib 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 rib 421 is laid above the lower chord flat rib 422 along the length direction of the side rib 4 and extends into the overlapping layer 5 above the bottom plate 2, the web member diagonal ribs 423 are obliquely connected between the upper chord flat rib 421 and the lower chord flat rib 422, the inclination angles of the two adjacent web member diagonal ribs 423 are opposite, and an included angle of 30-60 degrees is formed between every two adjacent web member diagonal ribs 423.

Further, the thickness of the laminated layer 5 is not preferably less than 50mm, and the laminated steel bar mesh 51 is disposed in the laminated layer 5, and the laminated steel bar mesh 51 is laid in the laminated layer 5.

It should be noted that the integral joint of the two-way multi-ribbed precast slab 1 side of the present application is preferably arranged in the minor stress direction of the laminated slab and is preferably arranged to avoid the maximum bending moment section, as shown in fig. 7A and 7B, a post-cast strip 8 is arranged at the joint, and an additional steel bar is arranged in the post-cast strip 8, and the structure of the additional steel bar may be the same as the structure of the triangular steel bar truss 32 or the structure of the planar steel bar truss 42 arranged in the side rib 4 or the middle rib 3, or may be other steel bar structures.

In order to further strengthen the connection of the post-cast strip 8, grooves are preferably arranged on the side ribs 4 at two sides of the post-cast strip 8, and the shear keys 81 are formed after one grade of non-shrinkage fine stone concrete higher than the laminated layer 5 is poured. The bottom longitudinal ribs of the transverse middle rib 3 and the side ribs 4 can be welded or mechanically directly connected in the post-cast strip 8, and can also be indirectly connected through the connecting plates 82, namely the connecting plates 82 are respectively arranged at two sides of the post-cast strip 8, the bottom longitudinal ribs of the transverse middle rib 3 and the side ribs 4 are directly welded on the connecting plates 82 in a factory, and then the connecting plates 8 are welded together in a construction site.

Referring to fig. 8, the connection between the bi-directional multi-ribbed precast slab 1 and the end bearer beam 6 and between the bi-directional multi-ribbed precast slab 1 and the side bearer beam 7 of the present application may be directly rested on the end bearer beam 6 or the side bearer beam 7. As shown in fig. 8A and 8B, the bottom ribs 311 at the two ends of the middle rib 3, the lower chord 322 of the triangular steel bar truss 32, the bottom ribs 411 at the two ends of the side rib 4, and the lower chord 422 of the planar steel bar truss 42 should extend a certain length, and be anchored in the end support beam 6 or the side support beam 7, then pouring concrete to pour the superposed layer 5, the bidirectional ribbed precast slab 1, the top of the end support beam 6 and the side support beam 7 into an integral structure, in the connection mode, the laying length of the middle rib 3 on the end support beam 6 is not less than 20mm, a convex beam can also be formed by directly laying the top end of the end support beam 6 provided with a connecting key and extending the connecting key into a gap between the bi-directional multi-ribbed precast slab 1 and the bi-directional multi-ribbed precast slab 1, and then pouring concrete to pour the laminated layer 5, the bidirectional multi-ribbed precast slab 1 and the top shear keys of the end support beam 6 and the side support beams 7 into an integral structure.

When the assembled reinforced concrete bidirectional multi-ribbed laminated slab floor system is not supported in the construction stage, the actual initial stress in the longitudinal steel bar at the bottom in the span of the longitudinal middle rib 3 and the side rib 4 caused by the changes of the effective height of the rib beam and the boundary condition of the support (simple support or continuous component) in the construction stage (the stage before the post-cast laminated layer 5 concrete does not reach the designed strength value) and the use stage (the stage after the laminated layer 5 concrete reaches the designed and specified strength value) of the dead weight load should be consideredThe advanced stress can be considered by multiplying the area of the longitudinal ribs 3 and 4 at the middle and bottom parts by an amplification factor calculated by the software according to the simulation of the cast-in-place floor system in the use stage, so that the area A of the bottom rib 311 of the longitudinally arranged middle rib 3 or the lower chord rib 342 of the triangular steel bar truss, the bottom rib 311 of the longitudinally arranged side rib 4 or the lower chord flat rib 422 of the planar steel bar truss is larger than the steel bar stress calculated by the software according to the simulation of the cast-in-place floor system (namely, the 'tensioned steel bar stress advancing phenomenon')_s1Comprises the following steps:

A_s1＝A_s0·η

wherein A is_s0The bottom longitudinal rib areas of the middle rib 3 and the side ribs 4 which are longitudinally distributed at the same position are obtained by integral calculation according to the non-assembly type cast-in-place floor system;

eta is the amplification coefficient of the areas of the longitudinal ribs at the bottoms of the longitudinal middle ribs 3 and the side ribs 4 caused by the stress advance of the steel bars during assembly;

beta is the ratio of the effective height of the prefabricated middle rib of the bidirectional multi-ribbed prefabricated slab 1 to the effective height of the superposed middle rib;

alpha is the ratio of the designed value of the dead weight load to the designed value of the total load, and the dead weight load comprises the dead weight of the bidirectional multi-ribbed precast slab 1 and the dead weight of the superposed layer 5; the total load comprises a dead load, a surface layer load and a live load, and is multiplied by a corresponding subentry coefficient and a corresponding combination value coefficient;

M₁in the construction stage, according to the consideration of a single-span simple support component, the dead load is a bending moment design value generated at the midspan bottom of a longitudinally-arranged middle rib 3 and a longitudinally-arranged side rib 4; m is a bending moment design value generated by the middle bottom of the longitudinally arranged middle rib 3 and the longitudinally arranged side rib 4 at the same position of the total load.

When the effective height of the ribs in the prefabrication is 165mm, the thickness of the superposed layer is 60mm, and the self-weight design value of the bidirectional multi-ribbed precast slab 1 is 2.5kN/m²The weight of the laminated layer 5 is 1.5kN/m²The surface layer load is 2.0kN/m²The live load is 5.0kN/m²Design value of bending moment M₁The design value M of the bottom bending moment in the middle of the span of a certain longitudinal middle rib 3 is 38 kN.m and the area A of the longitudinal rib at the middle bottom of the span of the longitudinal middle rib 3 are obtained by adopting structural calculation software YJK according to the modeling calculation of the T-shaped hollow slab floor_s0Is 534mm²Determining the amplification coefficient eta to be 1.8, and further determining the areas A of the bottom rib 311 of the middle rib 3 or the lower chord rib 342 of the triangular steel bar truss arranged longitudinally, the bottom rib 311 of the side rib 4 arranged longitudinally and the lower chord flat rib 422 of the plane steel bar truss_s1Is 961mm²。

1) in the mill, at first place bottom plate 2, well

rib

3 and 4 reinforcing bars of side rib in the mould and tie up well to predetermine in a wretched state on the 4 moulds of both sides side rib, pour 3 and 4 concrete of side rib of well rib, the completion of vibrating, pour 2 concrete of bottom plate and vibrate again, specifically do:

1.2) determining the area A of the bottom rib 311 of the longitudinal middle rib 3 or the lower chord 342 of the triangular steel bar truss, the bottom rib 311 of the longitudinal side rib 4 or the lower chord flat rib 422 of the plane steel bar truss_s1；

1.3) bottom longitudinal rib area A of longitudinal middle rib 3 and side rib 4_s1Determining the diameter and the number of the steel bars;

1.4) according to the conventional design result of the floor system and the diameter and the number of the longitudinal ribs at the bottoms of the longitudinal middle ribs 3 and the side ribs 4, in a factory, firstly, reinforcing steel bars of the bottom plate 2, the middle ribs 3 and the side ribs 4 are placed in a mould and tied, grooves are preset on the moulds of the side ribs 4 at two sides, concrete at the positions of the middle ribs 3 and the side ribs 4 is poured, the concrete is poured at the position of the bottom plate 2 and vibrated after the concrete is vibrated.

2) The concrete top surface of the bottom plate 2 is subjected to rough treatment, and the bidirectional ribbed precast slab 1 can be produced after curing and demoulding;

3) after the end support beam 6 and the side support beam 7 are constructed, hoisting the bidirectional multi-ribbed precast slab 1 in place, and placing two ends of the bidirectional multi-ribbed precast slab on the end support beam 6;

4) reserving a post-cast strip 8 at the abutted seam of the adjacent bidirectional multi-ribbed precast slabs 1, arranging additional reinforcing steel bars in the post-cast strip 8, welding or mechanically connecting bottom longitudinal bars of a transverse middle rib 3 and side ribs 4 in the post-cast strip or welding connecting plates 82 at two sides of the post-cast strip 8 together, and arranging a bottom die at the bottom of the post-cast strip 8 according to requirements;

5) and arranging a reinforcing mesh 51 in the laminated layer 5, pouring concrete in the laminated layer 5 by using the bidirectional multi-ribbed precast slab 1 as a permanent bottom die, and curing to finish the construction of the assembled reinforced concrete bidirectional multi-ribbed laminated slab floor system.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. The assembled reinforced concrete two-way multi-ribbed composite slab floor system is characterized by comprising two-way multi-ribbed precast slabs (1), a laminated layer (5), an end support beam (6), a side support beam (7) and a post-cast strip (8), wherein the end support beam (6), the side support beam (7) and a frame column are spliced to form an installation frame of the two-way multi-ribbed precast slabs (1), two ends of each two-way multi-ribbed precast slab (1) are placed on the end support beam (6), the post-cast strip (8) is arranged at the joint of the two-way multi-ribbed precast slabs (1), and the laminated layer (5) is arranged above the two-way multi-ribbed precast slabs (1) in a stacked mode to form the two-way multi-ribbed composite slab floor system;

the bidirectional multi-ribbed precast slab (1) comprises a bottom plate (2), a middle rib (3) and side ribs (4); the plurality of side ribs (4) are overlapped end to form an outer frame of the bidirectional multi-ribbed precast slab (1), the middle ribs (3) are transversely and longitudinally distributed in a crossed manner to divide the inner side of the outer frame formed by the side ribs (4) into a plurality of bottom plate mounting areas, and the bottom plate (2) is embedded in the bottom plate mounting areas; the middle rib (3) and the side ribs (4) are protruded downwards compared with the bottom plate (2), so that the outward protruding direction of the middle rib (3) and the side ribs (4) is opposite to the arrangement direction of the laminated layer (5).

2. The assembled reinforced concrete bidirectional multi-ribbed laminated slab floor system as claimed in claim 1, wherein the longitudinal cross-sectional area A of the bottom rib (311) of the longitudinally arranged middle rib (3) or the lower chord rib (342) of the triangular steel bar truss, the bottom rib (311) of the longitudinally arranged side rib (4) or the lower chord flat rib (422) of the planar steel bar truss_s1All are as follows:

A_s1＝A_s0·η

wherein A is_s0The area of the bottom longitudinal ribs of the middle rib (3) and the side rib (4) which are longitudinally distributed at the same position is obtained by integral calculation according to the non-assembly type cast-in-place floor system;

eta is the amplification coefficient of the area of the longitudinal ribs at the bottoms of the longitudinal middle rib (3) and the side rib (4) caused by the stress advance of the steel bar during assembly;

beta is the ratio of the effective height of the prefabricated middle rib of the bidirectional multi-ribbed prefabricated slab (1) to the effective height of the superposed middle rib;

alpha is the ratio of the designed value of the dead weight load to the designed value of the total load, and the dead weight load comprises the dead weight of the bidirectional multi-ribbed precast slab (1) and the dead weight of the superposed layer (5); the total load comprises a dead load, a surface layer load and a live load, and is multiplied by a corresponding subentry coefficient and a corresponding combination value coefficient;

M₁in the construction stage, according to the consideration of a single-span simple support component, the dead load is a bending moment design value generated at the midspan bottom of a middle rib (3) and a side rib (4) which are longitudinally arranged; m is a bending moment design value generated at the bottom of the middle rib (3) and the side rib (4) which are longitudinally arranged and the total load of which is at the same position.

3. The assembled reinforced concrete two-way multi-ribbed laminated slab floor system as claimed in claim 1 or 2, wherein a U-shaped framework (31) consisting of bottom ribs (311) and U-shaped ribs (312) or a triangular steel bar truss (32) is arranged in the middle rib (3); the top end of the U-shaped framework (31) or the triangular steel bar truss (32) penetrates through the bottom plate (2) and extends into the laminated layer (5), and the bottom end of the U-shaped framework or the triangular steel bar truss extends to the bottom of the middle rib (3).

4. The assembled reinforced concrete two-way multi-ribbed laminated slab floor system according to claim 3, wherein the triangular steel bar truss (32) comprises an upper chord rib (321), a lower chord rib (322), a vertical web bar rib (323), a bottom web bar straight rib (324) and a bottom web bar diagonal rib (325), the lower chord rib (322) is laid on two sides of the bottom of the triangular steel bar truss (32) along the length direction of the middle rib (3), the upper chord rib (321) is laid above the lower chord rib (322) along the length direction of the middle rib (3) and the two lower chord ribs (322) are respectively located at three vertexes of an isosceles triangle, the vertical web bar rib (323) spans two sides of the upper chord rib (321) and respectively extends to the lower chord rib (322) to form a closed isosceles triangle ring, the upper chord rib (321) extends to the laminated layer (5) above the base plate (2), the bottom web bar straight rib (324) and the bottom web bar diagonal rib (325) are distributed at intervals and the head and tail ribs are connected and laid at the two lower chord ribs (322) ) To (c) to (d); the bottom web bar straight ribs (324) are vertically connected with the lower chord ribs (322), and the bottom web bar inclined ribs (325) are obliquely connected between the two bottom web bar straight ribs (324) and form an included angle of 30-45 degrees with the bottom web bar straight ribs (324).

5. The assembled reinforced concrete bidirectional multi-ribbed laminated slab floor system according to claim 3, wherein an S-shaped framework (41) or a planar steel bar truss (42) is arranged in the side rib 4; the top end of the S-shaped framework (41) or the plane steel bar truss (42) penetrates through the bottom plate (2) and extends into the laminated layer (5), and the bottom end of the S-shaped framework or the plane steel bar truss 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 rib (422) is laid at the center of the bottom of the plane steel bar truss (42) along the length direction of the side rib (4), the upper chord flat rib (421) is laid above the lower chord flat rib (422) along the length direction of the middle rib (3) and extends into the overlapping layer (5) above the bottom plate (2), the web member diagonal ribs (423) are obliquely connected between the upper chord flat rib (421) and the lower chord flat rib (422), the inclination angles of the two adjacent web member diagonal ribs (423) are opposite, and an included angle of 30-60 degrees is formed between every two adjacent web member diagonal ribs.

6. The prefabricated reinforced concrete double multi-ribbed laminated slab floor system according to claim 1, wherein the integral joint of the plate side of the double multi-ribbed prefabricated slab (1) is arranged in the secondary stress direction of the laminated slab and avoids the section with the maximum bending moment, the post-cast strip (8) is arranged at the joint of the double multi-ribbed prefabricated slab 1, and additional steel bars are arranged in the post-cast strip (8).

7. The assembled reinforced concrete bidirectional multi-ribbed composite floor according to claim 1, wherein the adjacent two side ribs (4) of the post-cast strip (8) are provided with grooves, and the shear keys (81) are formed after non-shrinkage fine stone concrete is poured.

8. An assembled reinforced concrete bi-directional multi-ribbed laminated slab floor according to claim 7, characterized in that the transverse center rib (3) and the bottom longitudinal ribs of the side ribs (4) are directly connected in the post-cast strip (8) or indirectly connected through a connecting plate (82).

9. The construction method of the assembled reinforced concrete bidirectional multi-ribbed composite slab floor system of claim 1, which is characterized by comprising the following steps:

1) in a factory, firstly, the bottom plate (2), the middle rib (3) and the side ribs (4) are placed in a mould and bound, the mould with the side ribs (4) on two sides is preset with a groove, concrete at the middle rib (3) and the side ribs (4) is poured, the concrete is vibrated, and then the concrete at the bottom plate (2) is poured and vibrated;

2) the concrete top surface of the bottom plate (2) is subjected to rough treatment, and the bidirectional ribbed precast slab (1) can be produced after curing and demolding;

3) after the end support beam (6) and the side support beam (7) are constructed, hoisting the two-way ribbed precast slab (1) in place, and placing two ends of the two-way ribbed precast slab on the end support beam (6);

4) reserving a post-cast strip (8) at the abutted seam of adjacent two-way ribbed precast slabs (1), arranging additional steel bars in the post-cast strip (8), welding or mechanically connecting bottom longitudinal bars of a transverse middle rib (3) and side ribs (4) in the post-cast strip or welding connecting plates (82) on two sides of the post-cast strip (8) together, and arranging a bottom die at the bottom of the post-cast strip (8) according to requirements;

5) and (3) arranging a reinforcing mesh (51) in the laminated layer (5), pouring concrete in the laminated layer (5) by taking the bidirectional multi-ribbed precast slab (1) as a permanent bottom die, and curing to finish the construction of the assembled reinforced concrete bidirectional multi-ribbed laminated slab floor system.

10. The construction method of the assembled reinforced concrete bidirectional multi-ribbed composite slab floor system according to claim 9, wherein the step 1) is as follows:

1.1) calculating the amplification factor of the areas of longitudinal ribs at the bottoms of a longitudinal middle rib (3) and a side rib (4) caused by the stress lead of the steel bar through the following formula,

wherein beta is the ratio of the effective height of the prefabricated middle rib of the bidirectional multi-ribbed prefabricated slab (1) to the effective height of the superposed middle rib;

M₁in the construction stage, according to the consideration of a single-span simple support component, the dead load is a bending moment design value generated at the midspan bottom of a middle rib (3) and a side rib (4) which are longitudinally arranged; m is a bending moment design value generated at the midspan bottom of a middle rib (3) and a side rib (4) which are longitudinally arranged and have the same total load at the same position;

1.2) determining the longitudinal section area A of the bottom rib (311) of the middle rib (3) or the lower chord rib (342) of the triangular steel bar truss which is longitudinally arranged, the bottom rib (311) of the side rib (4) which is longitudinally arranged or the lower chord flat rib (422) of the plane steel bar truss_s1All are as follows:

A_s1＝A_s0·η

1.3) area A of longitudinal ribs at the bottom of the longitudinally arranged middle rib (3) and side rib (4)_s1Determining the diameter and the number of the steel bars;

1.4) according to the conventional design result of the floor system and the diameter and the number of the longitudinal ribs at the bottoms of the longitudinal middle ribs (3) and the side ribs (4), firstly, placing the bottom plate (2), the middle ribs (3) and the side ribs (4) in a mould and binding the steel bars in a factory, presetting grooves on the side rib (4) at two sides of the mould, pouring concrete at the middle ribs (3) and the side ribs (4), finishing vibrating, pouring the concrete at the bottom plate (2) and vibrating.