CN113250359B - Full precast concrete floor slab connection structure and design calculation method - Google Patents

Abstract

The invention discloses a full precast concrete floor slab connection structure and a design calculation method, wherein the connection structure comprises precast concrete floor slabs (1) at two sides, a rear reinforcing steel frame (2), a rear penetrating longitudinal bar (3) and rear poured concrete (4), and the side surface of the precast concrete floor slab (1) at the connection side is provided with a longitudinal through groove (11) and a plurality of vertical through grooves (12); the rear reinforcing steel bar frame (2) is arranged in the vertical through grooves (12) of the floor slabs on two sides in the middle; the rear penetrating longitudinal bars (3) penetrate through the rear reinforcing steel bar frame (2); and the post-cast concrete (4) is poured in the longitudinal through groove (11) and the plurality of vertical through grooves (12). The invention can obviously improve the shearing resistance, bending rigidity and bearing capacity in the whole precast floor slab surface, ensure the deformation coordination at the slab joint when bearing vertical load and achieve the use performance similar to the integral cast-in-situ floor system. The invention has reliable performance, simple structure, quick construction and environmental protection.

Description

A kind of fully precast concrete floor connection structure and design calculation method

technical field

The invention relates to the technical field of building structure connection structures, in particular to a fully prefabricated concrete floor connection structure and a design calculation method.

Background technique

As an important part of the overall building structure, the floor slab not only bears the vertical load, but also transmits the horizontal load generated by the earthquake and wind load to the anti-side system. The traditional steel-cast-in-place concrete floor shows excellent mechanical properties, but a large number of workers are still required to make on-site formwork, steel bar binding and concrete pouring during the construction process, and there are problems such as cumbersome construction, large workload and low construction efficiency; In addition, with the shortage of labor, the required labor costs have greatly increased; large-scale on-site wet operations have caused environmental pollution, which is not in line with the development direction of construction industrialization in my country and is contrary to the concept of sustainable development.

Existing floor slab forms mainly include traditional truss reinforced floor slabs, detachable bottom form truss reinforced floor slabs and composite slab composite slabs, etc. However, after market verification, these products are not yet mature residential building floor solutions. The traditional truss reinforced floor deck profiled steel plate is exposed, which has poor aesthetics, hinders decoration, poor user experience, and low consumer acceptance in residential buildings; the construction process of the truss reinforced floor deck with removable bottom formwork is complicated, and the actual bottom form The reusability is not high, and the cost is high; while the composite floor slab requires the actual slab thickness to be greater than 150mm, and its applicability is limited in residential buildings where the slab thickness is generally 100-120mm.

In order to solve the corresponding problems, there are also researches related to fully prefabricated floor slabs connected by slot holes. The fully prefabricated floor slabs connected by slot holes can meet the engineering requirements of complete factory production of components and on-site assembly and installation, and a small amount of wet work on site can significantly improve the performance. The construction efficiency is more green and environmentally friendly, and the economic benefits are significant. However, due to the limitation of the floor size during transportation, there will inevitably be joints between adjacent prefabricated floors. The physical connection joints between fully prefabricated slabs affect the in-plane shear, flexural rigidity and bearing capacity of the slabs, resulting in a significant reduction in the integrity of the slabs; in addition, under the action of vertical loads, the fully prefabricated slabs on both sides of the joints have uncoordinated deformations, etc. The problem leads to the destruction of the decoration and decoration at the seam, which affects the comfort and aesthetics of use.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention proposes a connection structure and design calculation method of a fully prefabricated concrete floor. The deformation of the joints is coordinated, and the performance similar to the overall cast-in-place floor can be achieved. The invention relates to a fully prefabricated assembled floor slab, which has the advantages of reliable performance, simple structure, rapid construction, green environmental protection and the like.

The present invention is realized in this way:

The present invention first provides a fully prefabricated concrete floor connection structure, comprising prefabricated concrete floor slabs 1 on both sides, rear reinforcement frames 2, rear through longitudinal bars 3 and post-cast concrete 4, wherein:

The precast concrete floor slab 1 is provided with a longitudinal through groove 11 and a plurality of vertical through grooves 12 on the side of the connecting side. The longitudinal through groove 11 runs through the length of the floor slab vertically. The thickness of the penetrating floor slab; the transverse reinforcing bars 13 in the precast concrete floor 1 form U-shaped rib 14 between the adjacent vertical penetrating grooves 12 and leak into the longitudinal penetrating grooves 11;

The rear reinforcement frame 2 is centrally arranged in the vertical through groove 12 formed by the butt joints of the floor slabs on both sides;

The rear through longitudinal reinforcement 3 passes through the rear reinforcement frame 2 and the U-shaped reinforcement 14 and is symmetrically arranged in the longitudinal through grooves 11 of the floor slabs on both sides;

The post-cast concrete 4 is poured in the longitudinal through-grooves 11 and a plurality of vertical through-grooves 12 , and is anchored with the post-installed reinforcing bar frame 2 and the post-installed through longitudinal bars 3 to form a long connecting block.

Preferably, the longitudinal through grooves 11 divide the precast concrete floor 1 into an upper area and a lower area on the connection side, and the transverse reinforcement 13 forms a closure between the upper area and the lower area between the adjacent vertical through grooves 12 The U-shaped rib 14.

Preferably, the cross section of the longitudinal through groove 11 is a trapezoidal constriction structure that is wide on the inside and narrow on the outside.

Preferably, the vertical through groove 12 is a trapezoidal constriction structure that is wide inside and narrow outside in the direction of the plate surface, and is symmetrical up and down along the center line of the vertical through groove 11 in the direction of plate thickness, and both are wide outside and narrow in the upper and lower sides. Trapezoidal necking structure.

Preferably, the vertical through grooves 12 are evenly spaced along the longitudinal through grooves 11 , and the vertical through grooves 12 and the longitudinal through grooves 11 have the same depth.

Preferably, the U-shaped rib 14 is formed by bending and butt-jointing the upper and lower transverse reinforcement bars 13 of the precast concrete floor 1 at the non-vertical penetration groove 12 on the connection side, or the non-vertical penetration groove of the upper and lower transverse reinforcement 13 at the connection side. The position 12 is the entire U-shaped rib 14 .

Preferably, the rear reinforcement frame 2 is a square reinforcement ring processed and formed in a factory.

Preferably, a transverse frame rib 21 is welded in the middle of the square reinforcement ring, and the transverse frame rib 21 is used for placing the rear penetration longitudinal rib 3 when passing through the rear reinforcement frame 2 Longitudinal ribs 3.

Preferably, the post-cast concrete 4 is ultra-high performance concrete UHPC.

The present invention also provides a design and calculation method for a connection structure of a fully precast concrete floor, comprising the following steps:

Step 1. Determine the size and reinforcement of the precast concrete floor:

The size of the precast concrete floor includes the thickness h, the length l, and the reinforcement of the floor is a@b, where a is the diameter of the transverse reinforcement of the precast concrete floor, and b is the spacing of the transverse reinforcement of the precast concrete floor;

Step 2: Determine the size of the slot holes of the vertical through-slot 11 and the vertical through-slot 12:

，板厚方向倾角

；纵向贯通槽11的尺寸包括内宽k₁、外宽k₂和倾角

；Both have the same depth, both are s, the size of the vertical through groove 12 includes the inner width w ₁ of the board surface, the outer width w ₂ of the board surface, the middle inner width w ₃ and the middle outer width w ₄ , the horizontal inclination angle of the board surface direction

, the inclination angle in the thickness direction

; The size of the longitudinal through groove 11 includes the inner width k ₁ , the outer width k ₂ and the inclination angle

;

Each dimension has the following relationship:

、

、

、s即可确定w₂、w₃、w₄、k₂的尺寸；Determine w ₁ , k ₁ ,

,

,

, s can determine the size of w ₂ , w ₃ , w ₄ , k ₂ ;

、

、

、s的尺寸，按照如下原则对槽孔进行验算：Step 3: Predetermine a w ₁ , k ₁ ,

,

,

, s size, check the slot hole according to the following principles:

The shear-resistant groove formed after the UHPC is poured in the vertical through groove 12 will not cause shear damage to the adjacent precast concrete floor area;

The shear-resistant groove formed after the UHPC is poured in the vertical through groove 12 will not cause partial pressure failure in the adjacent precast concrete floor area;

式1

Formula 1

式2

Formula 2

in,

为竖向贯通槽12内UHPC浇筑完成之后的抗剪承载力，

为竖向贯通槽12相邻预制混凝土楼板混凝土的抗剪承载力，

为相邻预制混凝土楼板局压承载力，

、

、

分别为UHPC抗剪强度设计值、预制楼板用混凝土抗剪强度设计值和抗压强度设计值，

为U型横向钢筋13的抗剪强度折减系数，通过试验确定；In the formula,

is the shear bearing capacity after the UHPC pouring in the vertical through groove 12 is completed,

is the shear bearing capacity of the adjacent precast concrete floor concrete of the vertical through groove 12,

is the partial compressive bearing capacity of the adjacent precast concrete floor,

,

,

are the design value of UHPC shear strength, the design value of shear strength and compressive strength of concrete for precast floor slabs,

is the shear strength reduction factor of the U-shaped transverse steel bar 13, which is determined by experiments;

According to the above formula, verify whether the basic parameters of the slot meet the requirements of Equation 1 and Equation 2. If it meets the requirements, go to the next step. If not, change the size of the slot and continue to check the calculation of Equation 1 and Equation 2 until it is satisfied, and then proceed to the next step. ;

Step 4, after the slot size meets the requirements, carry out the calculation of the bearing capacity of the connection structure of the full precast concrete floor, including the shear bearing capacity and the bending bearing capacity;

包括：后置钢筋架2提供的剪力

、竖向贯通槽12内后浇UHPC提供的剪力

、以及预制混凝土楼板之间的摩擦力

，即Shear capacity at the interface

Included: Shear force provided by rear rebar frame 2

, Shear force provided by post-cast UHPC in vertical through groove 12

, and the friction between precast concrete slabs

,Right now

为后置钢筋架2抗剪强度折减系数，通过试验标定，

为两预制混凝土楼板交界面的摩擦系数，N为两预制混凝土楼板之间的轴力；In the formula,

is the reduction factor of shear strength of the rear steel frame 2, which is calibrated through experiments,

is the friction coefficient of the interface between the two precast concrete floors, and N is the axial force between the two precast concrete floors;

Calculation of flexural capacity:

为后置钢筋架2抗弯强度设计值的折减系数，

为后置钢筋架2抗弯强度设计值，

为后置钢筋架2的截面面积，

为后置钢筋架2的高度，

为UHPC抗弯强度设计值折减系数，通过试验标定；

为UHPC抗弯强度设计值，

为UHPC抗弯面积；

is the reduction factor of the design value of the flexural strength of the rear steel frame 2,

is the design value of the flexural strength of the rear steel frame 2,

is the cross-sectional area of the rear reinforcement frame 2,

is the height of the rear reinforcement frame 2,

It is the reduction factor for the design value of UHPC flexural strength, which is calibrated through experiments;

is the design value for the flexural strength of UHPC,

is the bending area of UHPC;

Step 5: Calculate the shear bearing capacity and flexural bearing capacity within the range of the plate length l.

Shear bearing capacity calculation:

Calculation of flexural capacity:

After the design of the connection structure of the precast concrete floor is completed, compare V and M with the shear force and bending moment at the joint position of the floor slabs calculated according to the actual load of the structure.

Compared with the prior art, a fully precast concrete floor connection structure provided by the present invention has the following advantages:

According to the invention, slot holes with good horizontal and vertical embedding functions are evenly distributed at the joints of two adjacent precast concrete floor slabs. The out-of-plane reliable connection is formed, and the intermediate connection structure after concrete is poured to ensure the tensile performance in the direction perpendicular to the slab joint and the shear performance in the direction parallel to the slab joint. The stiffness of the joint and the cooperative deformation ability between adjacent prefabricated slabs are beneficial to the improvement of the integrity of the floor slab.

The pouring material of the present invention adopts UHPC, which fully utilizes the performance advantages of the post-casting UHPC material, and has excellent properties such as ultra-high strength, ultra-high toughness, ultra-long durability and the like. Compared with ordinary concrete, it can form stronger bond anchorage to steel bars.

The fully precast concrete floor has no overhanging steel bars, and the interface does not need special treatment, which significantly reduces the difficulty of floor processing in the factory, and facilitates the standardized and automated production of precast floor slabs; during on-site construction, only simple support for the post-pouring area can be poured. Concrete, the construction is simple and fast, which can greatly save the construction period.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that are required to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary, and for those of ordinary skill in the art, other implementation drawings can also be obtained according to the extension of the drawings provided without creative efforts.

The structures, proportions, sizes, etc. shown in this specification are only used to cooperate with the contents disclosed in the specification, so as to be understood and read by those who are familiar with the technology, and are not used to limit the conditions for the implementation of the present invention, so there is no technical The substantive meaning above, any modification of the structure, the change of the proportional relationship or the adjustment of the size, without affecting the effect that the present invention can produce and the purpose that can be achieved, should still fall within the technical content disclosed in the present invention. In the range.

1 is a schematic diagram of the overall structure of a fully precast concrete floor slab of an embodiment;

Fig. 2 is the partial enlarged schematic diagram of the connection structure of the precast concrete floor;

Fig. 3 is the schematic diagram of the slot hole structure of the precast concrete floor;

Figure 4 is a schematic diagram of the arrangement of slot holes and transverse reinforcement in the precast concrete floor;

Figure 5 is a schematic diagram of the structure of the transverse reinforcement at the position of the non-slotted hole;

Figure 6 is a schematic diagram of the rear steel frame structure;

7 is a schematic diagram of the structure of the connection block;

8 is a schematic diagram of the overall structure of the connection of the fully precast concrete floor slabs of an embodiment;

Figure 9 is a schematic diagram of the connection of a plurality of precast concrete floor slabs;

Figure 10 is a schematic top view of the vertical through groove (the direction of the board surface);

Figure 11 is a schematic front view of a vertical through groove (plate thickness direction);

Fig. 12 is a schematic side view of the longitudinal through-groove (in the direction of the plate end).

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention more clearly understood, the embodiments of the present invention will be further described in detail below with reference to the embodiments and the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but not to limit the present invention.

In the description of the present invention, it is to be understood that the terms "comprising/comprising", "consisting of" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a product, device, A process or method includes not only those elements, but may also include other elements, if desired, not expressly listed, or elements inherent to the product, device, process, or method. Without further limitation, an element defined by the phrases "comprising/comprising", "consisting of" does not preclude the presence of additional elements in the product, device, process or method comprising said element same elements.

In the present invention, unless otherwise expressly specified and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection , or integrated; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of the two elements or the interaction relationship between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

It is also to be understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," "outer," etc. indicate orientation or The positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device, component or structure referred to must have a specific orientation, be configured in a specific orientation or The operation should not be construed as a limitation to the present invention.

The implementation of the present invention will be described in detail below with reference to the preferred embodiments.

Referring to FIG. 1, a fully precast concrete floor connection structure includes precast concrete floor slabs 1 on both sides, rear reinforcement frames 2, rear penetration longitudinal bars 3 and post-cast concrete 4, wherein,

The precast concrete floor slab 1 is provided with a longitudinal through groove 11 and a plurality of vertical through grooves 12 on the side of the connection side. Through the thickness of the floor slab, the vertical through-groove 12 and the vertical through-groove 11 intersect and penetrate each other. In addition, the transverse reinforcement bars 13 in the precast concrete floor 1 are formed between adjacent vertical penetration grooves 12 , that is, U-shaped ribs 14 are formed at the non-vertical penetration grooves 12 on the connection side and leak into the longitudinal penetration grooves 11 .

Obviously, the side of the connecting side is the side where the two precast concrete floor slabs 1 are connected to each other, and the present invention is the longitudinal side of the floor slab. A certain depth s is opened inside to form slot holes, and the vertical through-slots 12 are evenly spaced along the longitudinal through-slots 11. The vertical through-slots 12 pass through the longitudinal through-slots 11 downward from the top surface of the floor slab and through to the bottom surface of the floor slab.

The rear reinforcement frame 2 is centrally arranged in the vertical through grooves 12 of the floor slabs on both sides; after the connecting sides of the floor slabs on both sides are butted, the vertical through grooves 12 are butted and merged into a complete slot hole, as shown in Figure 2, the rear The reinforcement frame 2 is placed in the slot, and temporary fixing measures can be used to temporarily fix the rear reinforcement frame 2 during construction, so that it is basically located in the center of the slot and does not shake or fall.

The rear penetrating longitudinal bars 3 pass through the rear reinforced frame 2 and the U-shaped rib 14 and are longitudinally symmetrically arranged in the longitudinal penetrating grooves 11 of the floor slabs on both sides; In the longitudinal through groove 11 of the floor slab, the rear through longitudinal bars 3 are penetrated from the rear reinforcement frame 2 and the U-shaped reinforcement 14. After the concrete is poured, the rear reinforcement frame 2 and the U-shaped reinforcement 14 are paired with the rear through longitudinal reinforcement 3. Forming restraint and tie effect.

In addition, since the vertical penetration groove 12 is divided into an upper area and a lower area by the vertical penetration groove 11 , by setting the transverse reinforcement 13 at the position of the non-vertical penetration groove 12 as a U-shaped rib, the rear penetration longitudinal reinforcement 3 is restrained while being restrained. The integrity of the concrete at the upper and lower regions of the longitudinal through groove 11 at the position of the non-vertical through groove 12 can be enhanced.

The post-cast concrete 4 is poured in the longitudinal through grooves 11 and a plurality of vertical through-grooves 12 , and is anchored with the rear reinforcement frame 2 and the rear through longitudinal reinforcement 3 to form a long connecting block, as shown in FIG. 7 .

In the present invention, the post-cast concrete 4 adopts ultra-high performance concrete UHPC. UHPC has excellent properties such as ultra-high strength, ultra-high toughness, and ultra-long durability. Compared with ordinary concrete, it can form stronger bonding and anchoring effect on steel bars in slot holes (anchoring performance is about 5~7 times that of ordinary C30 concrete. ), the anchorage length of the stressed steel bars in the tensile reinforced concrete can be reduced from 35d corresponding to C30 concrete to 5d~7d, that is, while ensuring the bearing capacity, stiffness and ductility of the slab joints between the fully prefabricated floors, the anchorage length of the steel bars can be reduced to The 1/7~1/5 of the C30 concrete anchorage significantly reduces the size of the rear reinforcement, thereby effectively controlling the size of the slot hole, the amount of reinforcement and the area of the post-cast UHPC area, and the economic benefits are significant.

In the present invention, as shown in FIG. 1 and in conjunction with FIG. 12 , the cross section of the longitudinal through groove 11 is a trapezoidal constriction structure that is wide inside and narrow outside. tensile strength.

In the present invention, as shown in FIG. 3 in conjunction with FIGS. 10 and 11 , the vertical through groove 12 is a trapezoidal constriction structure with an inner width and an outer narrow in the plate surface direction, and the vertical through groove 11 in the plate thickness direction is up and down along the center line of the longitudinal through groove 11 . Symmetrical, and the upper and lower sides are both wide outside and narrow inside the trapezoidal constriction structure. By designing the shape of the inner width and outer narrowness in the direction of the slab surface, the effective connection between the post-cast UHPC and the precast concrete slab in the horizontal and vertical directions is ensured, and the rear reinforcement frame 2 is used to jointly resist the shear force and vertical direction of the parallel slab joint. The tensile force in the direction of the slab joint; the slab thickness direction is a symmetrical structure with a narrow upper and lower width in the middle with the center line of the slab thickness as the symmetry axis, which ensures an effective connection between the post-cast UHPC and the precast concrete slab in the out-of-plane direction, and cooperates with the rear reinforcement frame. 2 Commonly resist positive and negative bending moments and deformations under vertical loads.

In the present invention, the vertical through grooves 12 are evenly spaced along the longitudinal through grooves 11 , and the vertical through grooves 12 and the longitudinal through grooves 11 have the same depth. From the perspective of construction technology, the depth of the slot holes is the same, which is convenient for opening. In addition, the spacing of the vertical through grooves 12 in the present invention is consistent with the spacing of the transverse reinforcement bars 13 in the floor slab, so as to avoid the transverse reinforcement bars in the precast concrete floor slab, as shown in FIG. 4 . Show.

In the present invention, as shown in FIGS. 2 and 5 , the upper and lower transverse reinforcing bars 13 of the precast concrete floor 1 are bent and butt-jointed at the non-vertical through grooves 12 on the connecting side to form U-shaped bars 14, or the upper and lower transverse reinforcing bars 13 are on the connecting side. The position of the non-vertical through groove 12 is the entire U-shaped rib 14 , and the rear through longitudinal rib 3 is penetrated in the U-shaped rib 14 . By bending the transverse reinforcement into a U-shaped reinforcement, the rear through longitudinal reinforcement 3 passes through the U-shaped reinforcement during the penetration, on the one hand, the connection between the precast concrete of the floor and the post-cast UHPC can be strengthened, and on the other hand, it can be In conjunction with the rear reinforcement frame, a certain embedded and tie effect is formed on the rear penetration longitudinal reinforcement. The rear reinforcement frame and the rear penetration longitudinal reinforcement work together to firmly connect the precast concrete floors on both sides to form a whole.

In the present invention, as shown in FIG. 6 and in conjunction with FIG. 2 , the rear reinforcement frame 2 is a square reinforcement ring processed and formed in a factory, and a transverse reinforcement rib 21 is welded in the middle of the square reinforcement ring, and the transverse reinforcement reinforcement 21 is used for the rear installation. When the penetrating longitudinal bars 3 are pierced from the rear reinforcing bar frame 2, the rear penetrating longitudinal bars 3 are placed. The transverse frame rib 21 is welded at the middle position of the square reinforcement ring. By placing the rear through longitudinal rib 3 on the transverse frame rib 21, the rear through longitudinal rib 3 can basically be located in each vertical through groove 12. The middle part of the plate thickness direction is symmetrical up and down, the structure layout is more reasonable, and the force is more uniform.

The splicing state of the connection structure is shown in FIG. 8 , and the two left and right precast concrete floor slabs 1 are meshed with each other through the connection structure. When three or more precast concrete floor slabs are connected, the connection structure of the present invention can be used to complete the splicing of the two floor slabs to form a whole floor slab, and then the splicing between the two floor slabs can be performed, as shown in FIG. 9 .

The connection structure of a fully precast concrete floor provided by the present invention is designed and calculated according to the following design calculation method:

Step 1. Determine the size and reinforcement of the precast concrete floor:

The size of the precast concrete floor includes the thickness h, the length l, and the reinforcement of the floor is a@b, where a is the diameter of the transverse reinforcement of the precast concrete floor, and b is the spacing of the transverse reinforcement of the precast concrete floor;

Step 2: Determine the size of the slot holes of the vertical through-slot 11 and the vertical through-slot 12:

，板厚方向倾角

；如图12所示，纵向贯通槽11的尺寸包括内宽k₁、外宽k₂和倾角

；Both have the same depth, both of which are s. As shown in Figures 10 and 11, the dimensions of the vertical through groove 12 include the inner width w ₁ of the board surface, the outer width w ₂ of the board surface, the middle inner width w ₃ and the middle outer width w ₄ , the horizontal inclination of the board direction

, the inclination angle in the thickness direction

; As shown in Figure 12, the size of the longitudinal through groove 11 includes the inner width k ₁ , the outer width k ₂ and the inclination angle

;

Each dimension has the following relationship:

、

、

、s即可确定w₂、w₃、w₄、k₂的尺寸；Determine w ₁ , k ₁ ,

,

,

, s can determine the size of w ₂ , w ₃ , w ₄ , k ₂ ;

、

、

、s的尺寸，按照如下原则对槽孔进行验算：Step 3: Predetermine a w ₁ , k ₁ ,

,

,

, s size, check the slot hole according to the following principles:

The shear-resistant groove formed after the UHPC is poured in the vertical through groove 12 will not cause shear damage to the adjacent precast concrete floor area;

The shear-resistant groove formed after the UHPC is poured in the vertical through groove 12 will not cause partial pressure failure in the adjacent precast concrete floor area;

式1

Formula 1

式2

Formula 2

in,

为竖向贯通槽12内UHPC浇筑完成之后的抗剪承载力，

为竖向贯通槽12相邻预制混凝土楼板混凝土的抗剪承载力，

为相邻预制混凝土楼板局压承载力，

、

、

分别为UHPC抗剪强度设计值、预制楼板用混凝土抗剪强度设计值和抗压强度设计值，

为弯折成U型的横向钢筋13的抗剪强度折减系数，通过试验确定；In the formula,

is the shear bearing capacity after the UHPC pouring in the vertical through groove 12 is completed,

is the shear bearing capacity of the adjacent precast concrete floor concrete of the vertical through groove 12,

is the partial compressive bearing capacity of the adjacent precast concrete floor,

,

,

are the design value of UHPC shear strength, the design value of shear strength and compressive strength of concrete for precast floor slabs,

is the shear strength reduction factor of the transverse steel bar 13 bent into a U-shape, determined by experiments;

According to the above formula, verify whether the basic parameters of the slot meet the requirements of Equation 1 and Equation 2. If it meets the requirements, go to the next step. If not, change the size of the slot and continue to check the calculation of Equation 1 and Equation 2 until it is satisfied, and then proceed to the next step. ;

Step 4: After determining the size of the slot hole, carry out the calculation of the bearing capacity of the connection structure of the fully precast concrete floor, including the shear bearing capacity and the bending bearing capacity;

包括：后置钢筋架2提供的剪力

、竖向贯通槽12内后浇UHPC提供的剪力

、以及预制混凝土楼板之间的摩擦力

，即Shear capacity at the interface

Included: Shear force provided by rear rebar frame 2

, Shear force provided by post-cast UHPC in vertical through groove 12

, and the friction between precast concrete slabs

,Right now

为后置钢筋架2抗剪强度折减系数，通过试验标定，

为两预制混凝土楼板交界面的摩擦系数，N为两预制混凝土楼板之间的轴力；In the formula,

is the reduction factor of shear strength of the rear steel frame 2, which is calibrated through experiments,

is the friction coefficient of the interface between the two precast concrete floors, and N is the axial force between the two precast concrete floors;

Calculation of flexural capacity:

为后置钢筋架2抗弯强度设计值的折减系数，

为后置钢筋架2抗弯强度设计值，

为后置钢筋架2的截面面积，

为后置钢筋架2的高度，

为UHPC抗弯强度设计值折减系数，通过试验标定；

为UHPC抗弯强度设计值，

为UHPC抗弯面积；

is the reduction factor of the design value of the flexural strength of the rear steel frame 2,

is the design value of the flexural strength of the rear steel frame 2,

is the cross-sectional area of the rear reinforcement frame 2,

is the height of the rear reinforcement frame 2,

It is the reduction factor for the design value of UHPC flexural strength, which is calibrated through experiments;

is the design value for the flexural strength of UHPC,

is the bending area of UHPC;

Step 5: Calculate the shear bearing capacity and flexural bearing capacity within the range of the plate length l.

Shear bearing capacity calculation:

Calculation of flexural capacity:

After the design of the connection structure of the precast concrete floor is completed, the V and M are compared with the shear force and bending moment of the floor splicing joint position calculated according to the actual load of the structure, as long as it is greater than the result of the structural calculation.

The design calculation method of the present invention is a corresponding design calculation method for a fully precast concrete floor connection structure of the present invention, the design idea is clear and clear, provides a theoretical basis for checking the bearing capacity of the fully precast concrete floor connection structure, and is convenient for engineering applications Professionals perform design calculations.

The above descriptions are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (9)

1. The utility model provides a full precast concrete floor joint construction, its characterized in that includes precast concrete floor (1), rearmounted reinforcing bar frame (2), the rearmounted longitudinal bar (3) and post-cast concrete (4) of running through of both sides, wherein:

the side surface of the connecting side of the precast concrete floor slab (1) is provided with a longitudinal through groove (11) and a plurality of vertical through grooves (12), the longitudinal through groove (11) longitudinally penetrates through the length of the floor slab, and the vertical through groove (12) is arranged on the longitudinal through groove (11) and vertically penetrates through the thickness of the floor slab; the transverse steel bars (13) in the precast concrete floor slab (1) form U-shaped steel bars (14) between the adjacent vertical through grooves (12) and are exposed in the longitudinal through grooves (11);

the rear reinforcing steel bar frame (2) is arranged in the center in a vertical through groove (12) formed by butt joint of floor slabs on two sides;

the rear penetrating longitudinal bars (3) penetrate through the rear reinforcing steel bar frame (2) and the U-shaped bars (14) and are symmetrically arranged in the longitudinal through grooves (11) of the floor slabs on two sides;

the post-cast concrete (4) is ultra-high performance concrete UHPC, is poured in the longitudinal through grooves (11) and the vertical through grooves (12), and is anchored with the post-reinforcing steel bar frame (2) and the post-penetrating longitudinal bars (3) to form a through-length connecting block.

2. The connection configuration according to claim 1,

the longitudinal through grooves (11) divide the precast concrete floor slab (1) into an upper area and a lower area on a connection side, and the transverse steel bars (13) form closed U-shaped bars (14) between the upper area and the lower area between the adjacent vertical through grooves (12).

3. The connection configuration according to claim 1,

the cross section of the longitudinal through groove (11) is of a trapezoidal necking structure with a wide inner part and a narrow outer part.

4. The connection configuration according to claim 3,

the vertical through groove (12) is of a trapezoidal necking structure with a wide inner part and a narrow outer part in the plate surface direction, and is vertically symmetrical along the central line of the longitudinal through groove (11) in the plate thickness direction, and the upper part and the lower part are of trapezoidal necking structures with wide outer parts and narrow inner parts.

5. The connection configuration according to claim 4,

the vertical through grooves (12) are uniformly distributed at intervals along the longitudinal through grooves (11), and the depths of the vertical through grooves (12) and the longitudinal through grooves (11) are the same.

6. The connection configuration according to claim 1,

the U-shaped ribs (14) are formed by bending and butting upper and lower layers of transverse steel bars (13) of the precast concrete floor slab (1) at the positions of the non-vertical through grooves (12) on the connecting side, or the upper and lower layers of transverse steel bars (13) are provided with the whole U-shaped ribs (14) at the positions of the non-vertical through grooves (12) on the connecting side.

7. The connection configuration according to claim 1,

the rear reinforcing steel bar frame (2) is a square reinforcing steel bar ring processed and formed in a factory.

8. The connection configuration according to claim 7,

the middle of the square reinforcing ring is welded with a transverse frame vertical bar (21), and the transverse frame vertical bar (21) is used for the rear through longitudinal bar (3) to be placed when the rear reinforcing frame (2) is penetrated.

9. A design calculation method of a full precast concrete floor slab connection construction according to any one of claims 1 to 8, comprising the steps of:

step 1, determining the size and reinforcing bars of a precast concrete floor slab (1):

the prefabricated concrete floor size comprises the plate thickness h and the plate length l, and the floor reinforcing steel bar comprises the transverse steel bar diameter a and the transverse steel bar spacing b;

step 2, determining the sizes of the slotted holes of the longitudinal through slot (11) and the vertical through slot (12):

the depth of the two grooves is the same and is s, and the size of the vertical through groove (12) comprises the inner width w of the plate surface₁Outer width w of the plate surface₂Middle inner width w₃And a middle outer width w₄Horizontal inclination angle of board surface

Inclination angle in plate thickness direction

(ii) a The dimension of the longitudinal through groove (11) comprises an inner width k₁Outer width k₂And inclination angle in depth direction

；

The following relationships exist for each dimension:

determining the basic size w of the slot₁、k₁、

、

、

S, other dimensions can be determined through the relationship;

step 3, checking the size of the slot hole, and presetting a w₁、k₁、

、

、

And the size of s, the slotted hole is checked according to the following principle:

shear damage of adjacent precast concrete floor areas can not be caused by shear grooves formed after UHPC is poured in the vertical through grooves (12);

the shear resistant groove formed after UHPC is poured in the vertical through groove (12) can not cause local pressure damage to the adjacent precast concrete floor area;

in the formula,

the shear-resistant bearing capacity of the UHPC in the vertical through groove (12) after the pouring is finished,

in order to resist the shearing bearing capacity of the precast concrete floor slab concrete,

for the local pressure bearing capacity of the precast concrete floor,

、

、

respectively is a designed value of UHPC shear strength, a designed value of precast concrete floor concrete shear strength and a designed value of compression strength,

determining the strength reduction coefficient of the steel bar of the precast concrete floor slab through tests;

verifying whether the basic parameters of the slotted hole meet the requirements of the formulas 1 and 2 according to the formula, if so, carrying out the next step, if not, changing the size and the angle of the slotted hole, continuing to carry out the verification of the formulas 1 and 2 until the size and the angle of the slotted hole meet the requirements, and then carrying out the next step;

step 4, after the size of the slotted hole meets the requirement, calculating the bearing capacity of the connecting structure of the full precast concrete floor slab, wherein the calculation includes shearing resistance bearing capacity and bending resistance bearing capacity;

shear-resisting bearing capacity at interface

The method comprises the following steps: shearing force provided by rear reinforcing steel bar frame (2)

Shear force provided by post-pouring UHPC in vertical through groove (12)

And the friction force between the precast concrete floors

I.e. by

In the formula,

the shear strength reduction coefficient of the rear reinforcing steel bar frame (2) is calibrated through tests,

the coefficient of friction of the interface of the two precast concrete floor slabs is N, and the axial force between the two precast concrete floor slabs is N;

calculating the bending resistance bearing capacity:

the reduction coefficient of the design value of the bending strength of the post reinforcing steel bar frame (2),

for the design value of the bending strength of the post-positioned reinforcing steel bar frame (2),

is the cross section area of the rear reinforcing steel bar frame (2),

is the height of the rear reinforcing steel bar frame (2),

the reduction coefficient is designed for the bending strength design value of UHPC, and is calibrated through tests;

for the designed value of the bending strength of UHPC,

is the UHPC bending resistance area;

step 5, calculating the shearing resistance bearing capacity and the bending resistance bearing capacity within the plate length l range;

and (3) calculating shearing resistance bearing capacity:

calculating the bending resistance bearing capacity:

and (3) after the connection structure of the precast concrete floor is designed, comparing the V and the M with the shearing force and the bending moment of the floor splicing joint position calculated by the structure according to the actual working condition load, wherein the comparison result is larger than the shearing force and the bending moment.

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