阅读说明：本技术 一种纵肋空心墙体及其预埋螺母连接节点和设计施工方法 (Longitudinal rib hollow wall, embedded nut connecting node thereof and design construction method ) 是由 刘洋 杨思忠 赵志刚 任成传 车向东 王炜 岑丽丽 刘立平 袁啸天 冯耀祖 唐国 于 2021-02-07 设计创作，主要内容包括：本发明的纵肋空心墙体及其预埋螺母连接节点和设计施工方法属于建筑结构领域,本发明通过在螺母外套设约束装置,提升螺母与混凝土粘结滑移性能,并提高节点区混凝土的抗开裂性能,同时提高节点承载力安装储备。竖向附加U形钢筋、水平附加槽型钢筋和水平附加梯形钢筋形成钢筋骨架,有效提高节点混凝土椎体破坏的承载力强度。U形底部加强钢筋将螺母、钢筋骨架与预制墙体钢筋网片有效连接,提高整体受力性能,并防止螺母与混凝土发生锚固破坏后出现节点失效现象。该预埋螺母连接节点受力合理、加工方便,安装快捷,成本较低。本发明可实现在具有贯通空腔的纵肋空心预制墙板中设置螺母,减轻纵肋空心预制墙板的自重,减小墙板的尺寸,提高安装效率。(The invention relates to a longitudinal rib hollow wall, an embedded nut connecting node thereof and a design and construction method, belonging to the field of building structures. Vertical additional U-shaped reinforcing steel bar, horizontal additional cell type reinforcing steel bar and horizontal additional trapezoidal reinforcing steel bar form the steel reinforcement skeleton, effectively improve the bearing capacity intensity of node concrete centrum destruction. The U-shaped bottom reinforcing steel bars effectively connect the nuts, the steel bar frameworks and the prefabricated wall body reinforcing mesh, so that the overall stress performance is improved, and the phenomenon of node failure after the nuts and concrete are anchored and damaged is prevented. The embedded nut connecting node is reasonable in stress, convenient to process, fast to install and low in cost. The nut can be arranged in the longitudinal rib hollow prefabricated wallboard with the through cavity, the self weight of the longitudinal rib hollow prefabricated wallboard is reduced, the size of the wallboard is reduced, and the installation efficiency is improved.)

1. The utility model provides a longitudinal rib hollow wall's embedded nut connected node which characterized in that includes:

the nut (1) is embedded in the wall longitudinal rib (7) along the vertical direction;

the constraint devices (2) are sleeved outside the nut (1) and are arranged at intervals along the vertical direction;

the steel bar framework comprises vertical additional U-shaped steel bars (3) and horizontal additional groove-shaped steel bars (4), wherein the vertical additional U-shaped steel bars (3) penetrate through the constraint device (2) and are arranged along the circumferential direction of the nut (1) at intervals, the horizontal additional groove-shaped steel bars (4) are two C-shaped steel bars arranged back to back, and the horizontal additional groove-shaped steel bars (4) are arranged along the vertical intervals and are bound with the vertical additional U-shaped steel bars (3) and the wall body reinforcing mesh (5).

2. The embedded nut connection node of the longitudinal rib hollow wall body as claimed in claim 1, wherein: the restraint device (2) comprises a key groove ring (21), restraint rings (22) and cross bars (23), the key groove ring (21) and the restraint rings (22) are circular arcs arranged concentrically, the radius of the key groove ring (21) is smaller than that of the restraint rings (22), the ends of the two key groove rings (21) and the ends of the two restraint rings (22) are connected in a hinged mode, the cross bars (23) are connected between the key groove rings (21) and the restraint rings (22), and the vertical additional U-shaped steel bars (3) penetrate through the cross bars (23).

3. The embedded nut connection node of the longitudinal rib hollow wall body as claimed in claim 2, wherein: the height of the keyway ring (21) is greater than the height of the confinement ring (22).

4. The embedded nut connection node of the longitudinal rib hollow wall body as claimed in claim 1, wherein: the steel reinforcement framework further comprises horizontal additional trapezoidal steel bars (6) arranged at vertical intervals, and the horizontal additional trapezoidal steel bars (6) are symmetrically connected to the outer side of the vertical additional U-shaped steel bars (3) in the vertical prefabricated wall body thickness direction and are bound with the wall body steel mesh sheets (5).

5. The embedded nut connection node of the longitudinal rib hollow wall body as claimed in claim 2, wherein: u-shaped bottom reinforcing steel bars (9) are symmetrically arranged at the position of the bottommost restraint device (2), the U-shaped bottom reinforcing steel bars (9) penetrate through the crossed cross rods (23), and the end parts of the U-shaped bottom reinforcing steel bars are bound with the wall body reinforcing mesh sheets (5) on the corresponding sides.

6. The utility model provides a vertical rib hollow wall, includes that wall body vertical rib (7) and wall body cavity (8), be equipped with wall body reinforcing bar net piece (5), its characterized in that in wall body vertical rib (7): the wall cavity (8) is a through cavity and further comprises the embedded nut connecting node of the longitudinal rib hollow wall body as claimed in any one of claims 1 to 5.

7. A design and construction method for an embedded nut connecting node of a longitudinal rib hollow wall body as claimed in any one of claims 1 to 5 is characterized by comprising the following steps:

s1, according to the volume V of the prefabricated wall, the density rho of the concrete material and the cavity rate r_VCalculating the dead weight standard value G of the prefabricated wall_mk＝ρV(1-r_V) Calculating a load increase coefficient K considering demoulding adsorption, a power increase effect and safety redundancy according to the formula (1);

phi in the formula (1)_dy、ψ_dy1、ψ_dy2Respectively has a power increase coefficient under non-demolding condition, a power increase coefficient under demolding condition of 1, and a power increase coefficient under demolding condition of 2, q_adFor mold release adsorption, A_mThe demold area of the component;

s2, taking the embedded nut connecting nodes as hinged supports, calculating each support reaction according to the beam model and considering the load increasing coefficient, and summing to obtain the total stress load F of the nut (1)_k；

S3, calculating the bonding anchoring strength tau of the nut (1) according to the formulas (3) and (4)_uAnd a basic anchoring length l_ab；

Wherein c is the thickness of the steel bar protective layer of the prefabricated wall body, f_cDesigned value of concrete compressive strength of prefabricated wall body, d_rIs the diameter of the nut (1), A_jIs the area of the confinement ring (22), f_jyDesigned value f for the strength of the confinement ring (22)_yIs the designed value of the yield strength of the nut (1), and s is the distance between vertically adjacent restraining rings (22);

s4, calculating the anchoring length l of the nut (1) according to the formula (5)_aAnd determining the total length l of the nut (1)_a1；

S5, calculating the breaking strength N of the longitudinal rib concrete cone under the tension state at the joint according to the formula (7)_rib；

In the formula A_ria、A_ricRespectively the actual projection area of the damage surface of the concrete cone of the longitudinal rib under the condition of considering the influence of the edge distance and the calculated projection area without considering the influence of the edge distance under the condition of tension at the joint_tThe design value of the tensile strength of the concrete is obtained;

s6, judging whether N is satisfied_rib≥F_kN, if the condition is satisfied, proceeding to the next step, if not, returning to S4-S5, re-determining the anchoring length l of the nut (1)_aAnd the total length l of the nut (1)_a1Until the condition is met;

s7, determining the structure and the annular inner diameter D of the vertically-attached U-shaped steel bar (3)_vrWherein D is_vr≥2.5d_ad；

S8, determining the length l of the bottom of the restraint ring (22) of the restraint device (2) with the vertically additional U-shaped steel bar (3) extending out of the bottommost part according to the formula (9)_adAnd determining the total length l of the vertically additional U-shaped steel bar (3)_ad1；

In the formula d_adThe diameter of the U-shaped steel bar (3) is vertically added;

s9, determining the structure of the horizontal additional channel-shaped steel bar (4);

s10, determining the structure of the horizontal additional trapezoidal steel bar (6);

s11, determining the structure of the U-shaped bottom reinforcing steel bar (9);

s12, mounting the restraint device (2) outside the nut (1);

s13, passing the vertical additional U-shaped steel bar (3) through the crossed cross rod (23) and binding the vertical additional U-shaped steel bar with the restraint device (2);

s14, vertically installing the nut (1) with the restraint device (2) and the vertically attached U-shaped steel bar (3) in the longitudinal rib (7) of the wall body;

s15, binding the horizontal additional groove-shaped steel bars (4) and the horizontal additional trapezoidal steel bars (6) with the vertical additional U-shaped steel bars (3) and the wall body steel bar net pieces (5) respectively to form a steel bar framework;

s16, enabling U-shaped bottom reinforcing steel bars (9) to penetrate through the crossed cross bars (23) of the restraint devices (2) at the bottom and binding with the wall reinforcing steel mesh sheets (5) on the corresponding sides;

and S17, pouring concrete, demolding and forming, and finally forming the embedded nut connecting node on the top of the prefabricated wall.

8. The method for designing and constructing the embedded nut connection node of the longitudinal rib hollow wall body as claimed in claim 7, wherein the area A of the nut (1) in the S3 is determined according to the formula (2)_rAnd diameter d_r：

Wherein n is selected from: two-point hoisting and taking 2; f. of_yThe design value of the yield strength of the nut (1) is obtained.

9. The design and construction method of the embedded nut connection node of the longitudinal rib hollow wall body as claimed in claim 7, wherein the area A of the vertically additional U-shaped steel bar (3) in S7 is determined according to the formula (8)_adAnd diameter d_ad；

In the formula: f. of_adFor the design value of the yield strength of the vertical additional U-shaped steel bars (3), m is the number of the vertical additional U-shaped steel bars (3), and 8, 2N is taken when 4 vertical additional U-shaped steel bars (3) are arranged_ribIs to considerThe safety reserve is increased by 1 time.

10. The method for designing and constructing the embedded nut connection node of the longitudinal rib hollow wall body as claimed in claim 7, wherein the area A of the U-shaped bottom reinforcing steel bar (9) in the S11 is determined according to the formula (11)_uAnd diameter d_u；

In the formula f_uyThe design value of the yield strength of the U-shaped bottom reinforcing steel bar (9) is obtained; j is the number of limbs of the U-shaped bottom reinforcing steel bars (9), 2 are taken as one U-shaped bottom reinforcing steel bar (9), and 4 are taken as two U-shaped bottom reinforcing steel bars (9); 0.7 is a reduction factor of the strength in consideration of the installation angle.

Technical Field

The invention belongs to the field of building structures, and particularly relates to a longitudinal rib hollow wall, an embedded nut connecting node thereof and a design and construction method.

Background

In order to meet the requirements of production and construction links such as demolding, overturning, hoisting, installation and the like, hoisting points are required to be arranged on the longitudinal rib hollow wall boards. The common hoisting points of the existing prefabricated wall mainly comprise three types: (1) pre-burying lifting ring lifting points, such as tool lifting rings and steel bar lifting rings; (2) pre-burying a hanging point of a hanging nail; (3) the preformed hole penetrates through the hoisting point. When the nuts are embedded in the existing longitudinal rib hollow wallboard, the larger longitudinal rib area needs to be ensured, so that the nuts are embedded in the longitudinal row hollow wallboard with the through cavity. And moreover, the longitudinal rib hollow wallboard with the embedded nuts needs a special lifting appliance when being lifted, and a semicircular groove is formed at the top of the prefabricated longitudinal rib hollow wallboard, so that local weakening is caused. In addition, the embedded nut has more exposed parts and poor out-of-plane stress performance.

Disclosure of Invention

The invention aims to provide a longitudinal rib hollow wall, an embedded nut connecting node thereof and a design and construction method, so as to solve the technical problems.

Therefore, the invention provides an embedded nut connecting node of a longitudinal rib hollow wall, which comprises:

the nuts are embedded in the longitudinal ribs of the wall body along the vertical direction;

the constraint devices are sleeved outside the nuts and are arranged at intervals along the vertical direction;

the steel bar framework comprises vertical additional U-shaped steel bars and horizontal additional groove-shaped steel bars, wherein the vertical additional U-shaped steel bars penetrate through the restraint device and are arranged at intervals along the circumferential direction of the nut, the horizontal additional groove-shaped steel bars are two C-shaped steel bars arranged in a back-to-back mode, and the horizontal additional groove-shaped steel bars are arranged at intervals along the vertical direction and are bound with the vertical additional U-shaped steel bars and the wall body steel mesh.

Preferably, the restraining device comprises a key groove ring, a restraining ring and a cross bar, the key groove ring and the restraining ring are circular arcs arranged concentrically, the radius of the key groove ring is smaller than that of the restraining ring, the ends of the two key groove rings and the ends of the two restraining rings are in hinged connection, the cross bar is connected between the key groove rings and the restraining ring, and the vertical additional U-shaped steel bar penetrates through the cross bar.

Preferably, the height of the keyway ring is greater than the height of the confinement ring.

Preferably, the steel reinforcement framework further comprises horizontal additional trapezoidal steel bars arranged at intervals along the vertical direction, and the horizontal additional trapezoidal steel bars are symmetrically connected to the outer side of the vertical additional U-shaped steel bars in the vertical direction in the thickness direction of the prefabricated wall body and are bound with the wall body steel mesh.

Preferably, U-shaped bottom reinforcing steel bars are symmetrically arranged at the bottommost restraint device, penetrate through the crossed rods and are bound with the wall reinforcing mesh sheets on the corresponding sides at the end parts.

In addition, the invention also provides a longitudinal rib hollow wall, which comprises a wall longitudinal rib, a wall cavity and the embedded nut connecting node of the longitudinal rib hollow wall, wherein the wall longitudinal rib is internally provided with a wall reinforcing mesh, and the wall cavity is a through cavity.

In addition, the invention also provides a design and construction method of the embedded nut connecting node of the longitudinal rib hollow wall, which comprises the following steps:

s1, according to the volume V of the prefabricated wall, the density rho of the concrete material and the cavity rate r_VCalculating the dead weight standard value G of the prefabricated wall_mk＝ρV(1-r_V) Calculating a load increase coefficient K considering demoulding adsorption, a power increase effect and safety redundancy according to the formula (1);

phi in the formula (1)_dy、ψ_dy1、ψ_dy2Respectively has a power increase coefficient under non-demolding condition, a power increase coefficient under demolding condition of 1, and a power increase coefficient under demolding condition of 2, q_adFor mold release adsorption, A_mThe demold area of the component;

s2, taking the embedded nut connecting nodes as hinged supports, calculating each support reaction according to the beam model and considering the load increasing coefficient, and summing to obtain the total stress load F of the nut_k；

S3, calculating the bonding anchoring strength of the nut 1 according to the formulas (3) and (4)τ_uAnd a basic anchoring length l_ab；

Wherein c is the thickness of the steel bar protective layer of the prefabricated wall body, f_cDesigned value of concrete compressive strength of prefabricated wall body, d_rIs the diameter of the nut, A_jIs the area of the confinement ring, f_jyDesigned value for the strength of the confinement rings, f_yThe design value of the yield strength of the nut is shown, and s is the distance between vertically adjacent constraint rings;

s4, calculating the anchoring length l of the nut according to the formula (5)_aAnd determining the total length l of the nut_a1；

l_a1≥l_a+20mm+15mm

l_a＝0.6ζ_al_ab

S5, calculating the breaking strength N of the longitudinal rib concrete cone under the tension state at the joint according to the formula (7)_rib；

A_ric＝π(d_r+2b_t)² (7)

In the formula A_ria、A_ricRespectively the actual projection area of the damage surface of the concrete cone of the longitudinal rib under the condition of considering the influence of the edge distance and the calculated projection area without considering the influence of the edge distance under the condition of tension at the joint_tThe design value of the tensile strength of the concrete is obtained;

s6, judging whether N is satisfied_rib≥F_kN, if the condition is satisfied, proceeding to the next step, if not, returning to S4-S5, and re-determining the anchoring length l of the nut_aAnd total length l of the nut_a1Until the condition is met;

s7, determining the structure and the annular inner diameter D of the vertically-attached U-shaped steel bar_vrWherein D is_vr≥2.5d_ad；

S8, determining the length l of the restraining ring bottom of the restraining device with the vertically additional U-shaped steel bar extending out of the bottommost part according to the formula (9)_adAnd determining the total length l of the vertically additional U-shaped steel bar_ad1；

l_ad1＝l_ad+d_ad+l_a (9)

In the formula d_adThe diameter of the U-shaped steel bar is vertically added;

s9, determining the structure of the horizontal additional channel-shaped reinforcing steel bar;

s10, determining the structure of the horizontal additional trapezoidal steel bar;

s11, determining the structure of the U-shaped bottom reinforcing steel bar;

s12, mounting the restraint device outside the nut;

s13, passing the vertical additional U-shaped steel bars through the crossed cross rods and binding the vertical additional U-shaped steel bars with the restraining devices;

s14, vertically installing the nut 1 with the restraint device and the vertically attached U-shaped steel bars in the longitudinal ribs of the wall body;

s15, binding the horizontal additional groove-shaped steel bars and the horizontal additional trapezoidal steel bars with the vertical additional U-shaped steel bars and the wall steel bar net pieces respectively to form a steel bar framework;

s16, enabling U-shaped bottom reinforcing steel bars to penetrate through the crossed cross bars of the bottom restraint device and binding with the wall reinforcing steel mesh sheets on the corresponding sides;

and S17, pouring concrete, demolding and forming, and finally forming the embedded nut connecting node on the top of the prefabricated wall.

Preferably, the area a of the nut in S3 is determined according to equation (2)_rAnd diameter d_r：

Wherein n is selected from: two-point hoisting and taking 2; f. of_yThe yield strength design value of the nut is obtained.

Preferably, the area A of the vertically additional U-shaped reinforcing bar in S7 is determined according to equation (8)_adAnd diameter d_ad；

In the formula: f. of_adThe yield strength design value of the vertical additional U-shaped steel bars is obtained, m is the number of the vertical additional U-shaped steel bars, and 8, 2N are taken when 4 vertical additional U-shaped steel bars are arranged_ribA safety reserve increased by a factor of 1 is considered.

Preferably, the area A of the U-shaped bottom reinforcing bar in S11 is determined according to equation (11)_uAnd diameter d_u；

In the formula f_uyThe design value of the yield strength of the U-shaped bottom reinforcing steel bar is obtained; j is the number of limbs of the U-shaped bottom reinforcing steel bars, one U-shaped bottom reinforcing steel bar is taken as 2, and two U-shaped bottom reinforcing steel bars are taken as 4; 0.7 is a reduction factor of the strength in consideration of the installation angle.

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

(1) according to the embedded nut connecting node of the longitudinal rib hollow wall, the constraint device is sleeved outside the nut, the key slot ring is tightly connected with the nut, the bonding and sliding performance of the nut and concrete is improved, and the constraint ring is arranged on the outermost side, so that the anti-cracking performance of the concrete in the node area is improved. The crossed rods form a bidirectional pin bolt effect, and the bearing capacity of the node is improved. Vertical additional U-shaped reinforcing steel bar, horizontal additional cell type reinforcing steel bar and horizontal additional trapezoidal reinforcing steel bar form the steel reinforcement skeleton, effectively improve the bearing capacity intensity of node concrete centrum destruction. The U-shaped bottom reinforcing steel bars effectively connect the nuts, the steel bar frameworks and the prefabricated wall body reinforcing mesh, so that the overall stress performance is improved, and the phenomenon of node failure after the nuts and concrete are anchored and damaged is prevented. The embedded nut connecting node is reasonable in stress, convenient to process, fast to install and low in cost.

(2) The embedded nut connecting node can realize the arrangement of the nut in the longitudinal rib hollow prefabricated wall plate with the through cavity, reduce the dead weight of the longitudinal rib hollow prefabricated wall plate, reduce the size of the wall plate and improve the installation efficiency.

(3) The invention provides a design and construction method of embedded nut connecting nodes of a longitudinal rib hollow wall, which provides a basis for design and production.

Drawings

Fig. 1 is a schematic diagram of an embedded nut connection node of a longitudinal rib hollow wall.

Fig. 2 is a schematic view of a section a-a in fig. 1.

Fig. 3 is a schematic view of a section B-B in fig. 1.

Fig. 4 is a schematic view of the restriction device.

Fig. 5 is a schematic view of the section C-C in fig. 4.

Figure 6 is a schematic view of the restriction device when it is open.

Fig. 7 is a schematic view of a horizontally attached trapezoidal bar.

The attached drawings are marked as follows: the reinforcing steel bar fixing structure comprises 1-nuts, 2-constraint devices, 21-key groove rings, 22-constraint rings, 23-cross rods, 24-bolts, 3-vertical additional U-shaped reinforcing steel bars, 4-horizontal additional groove-shaped reinforcing steel bars, 5-wall reinforcing steel bar net sheets, 6-horizontal additional trapezoidal reinforcing steel bars, 7-wall longitudinal ribs, 8-wall cavities and 9-U-shaped bottom reinforcing steel bars.

Detailed Description

In order to make the technical means, innovative features, objectives and functions realized by the present invention easy to understand, the present invention is further described below.

The examples described herein are specific embodiments of the present invention, are intended to be illustrative and exemplary in nature, and are not to be construed as limiting the scope of the invention. In addition to the embodiments described herein, those skilled in the art will be able to employ other technical solutions which are obvious based on the disclosure of the claims and the specification of the present application, and these technical solutions include technical solutions which make any obvious replacement or modification for the embodiments described herein.

In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", "both ends", "one end", "the other end", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "connected," and the like are to be construed broadly, such as "connected," which may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1 to 7, the embedded nut connection node of the longitudinal rib hollow wall is shown, wherein the longitudinal rib hollow wall comprises a wall longitudinal rib 7 and a wall cavity 8, and a wall reinforcing mesh 5 is arranged in the wall longitudinal rib 7. The embedded nut connecting node comprises a nut 1, a restraint device 2 and a steel reinforcement framework.

The nut 1 is embedded in the longitudinal rib 7 of the wall body along the vertical direction. The nut 1 is selected according to the design and is embedded in the prefabricated wall body, and the stress performance is good.

The restraint device 2 is sleeved outside the nut 1 and is arranged at intervals along the vertical direction. The restraint device 2 comprises a key groove ring 21, a restraint ring 22 and a cross rod 23, wherein the key groove ring 21 and the restraint ring 22 are circular arcs arranged concentrically, the radius of the key groove ring 21 is smaller than that of the restraint ring 22, and the ends of the two key groove rings 21 and the ends of the two restraint rings 22 are hinged. Specifically, the ends of the two spline rings 21 and the ends of the two confinement rings 22 are connected by the pins 24. The crossbar 23 is connected between the keyway ring 21 and the confinement ring 22. The key groove ring 21 is tightly connected with the nut 1, and the peripheral edge part of the outer circumference of the key groove ring 21 is provided with a chamfer, so that the bonding force between the nut 1 and concrete is improved. The provision of the confinement rings 22 can improve the crack resistance of the concrete in the node region. The cross bars 23 form a bi-directional pinning effect, improving the node bearing capacity installation reserve.

The height of the keyway ring 21 is not less than the diameter of the nut 1. The outer circumferential edge portion of the key groove ring 21 is provided with a chamfer of not more than 60 °. The diameter of the cross bar 23 is not less than 10 mm. The height of the keyway ring 21 is greater than the height of the confinement rings 22. The width of the restraint ring 22 is 30mm less than the thickness of the wall longitudinal rib 7. The top of the restraint means 2 is 15mm higher than the top of the vertically additional U-shaped reinforcement bar 3.

The steel reinforcement framework comprises vertical additional U-shaped steel bars 3 and horizontal additional groove-shaped steel bars 4, the vertical additional U-shaped steel bars 3 penetrate through the crossed rod 23 and are arranged at intervals along the circumferential direction of the nut 1, the horizontal additional groove-shaped steel bars 4 are two C-shaped steel bars arranged in a back-to-back mode, and the horizontal additional groove-shaped steel bars 4 are arranged at intervals along the vertical direction and are bound with the vertical additional U-shaped steel bars 3 and the wall body reinforcing mesh 5.

The steel reinforcement framework further comprises horizontal additional trapezoidal steel bars 6 arranged at intervals along the vertical direction, and the horizontal additional trapezoidal steel bars 6 are symmetrically connected to the outer side of the vertical additional U-shaped steel bars 3 in the vertical direction in the thickness direction of the prefabricated wall and are bound with the wall steel mesh 5.

U-shaped bottom reinforcing steel bars 9 are symmetrically arranged at the bottommost restraint device 2, the U-shaped bottom reinforcing steel bars 9 penetrate through the crossed rods 23, and the end parts of the U-shaped bottom reinforcing steel bars are bound with the wall body reinforcing mesh 5 on the corresponding side. The horizontal included angle between the U-shaped bottom reinforcing steel bars 9 and the thickness direction of the wall body is not less than 45 degrees.

The design and construction method of the embedded nut connecting node of the longitudinal rib hollow wall comprises the following steps:

s1, according to the volume V of the prefabricated wall, the density rho of the concrete material and the cavity rate r_VCalculating the dead weight standard value G of the prefabricated wall_mk＝ρV(1-r_V) Calculating a load increase coefficient K considering demoulding adsorption, a power increase effect and safety redundancy according to the formula (1) according to parameters such as load working conditions, component types, template types and the like;

phi in the formula (1)_dy、ψ_dy1、ψ_dy2Respectively has a power increase coefficient under non-demolding condition, a power increase coefficient under demolding condition of 1, and a power increase coefficient under demolding condition of 2, q_adFor mold release adsorption, A_mIs the part demold area. The values of the parameters are as shown in Table 1.

TABLE 1 parameter comparison table of various templates

S2, determining the standard value G of the self weight of the wallboard according to the weight of the wallboard determined in S1_mkAnd a load increase coefficient K, taking the embedded nut connecting node as a hinged support, calculating each support reaction according to the beam model and considering the load increase coefficient, and summing to obtain the total stress load F of the nut 1_k。

S3, calculating the bonding anchoring strength tau of the nut 1 according to the formulas (3) and (4)_uAnd a basic anchoring length l_ab；

Take 3.0

Wherein c is the thickness of the steel bar protective layer of the prefabricated wall body, f_cDesigned value of concrete compressive strength of prefabricated wall body, d_rIs the diameter of the nut 1, A_jTo constrain the area of the ring 22, f_jyDesigned value for the strength of the confinement rings 22, f_yS is the spacing between vertically adjacent confinement rings 22 for the designed value of the yield strength of the nut 1.

Determining the area A of the nut 1 according to equation (2)_rAnd diameter d_r：

Wherein n is selected from: two-point hoisting and taking 2; f. of_yThe yield strength design value for the nut 1.

S4, calculating the anchoring length l of the nut 1 according to the formula (5)_aAnd determines the total length l of the nut 1_a1；

l_a1≥l_a+20mm+15mm

l_a＝0.6ζ_al_ab

S5, calculating the breaking strength N of the longitudinal rib concrete cone under the tension state at the joint according to the formula (7)_rib；

A_ric＝π(d_r+2b_t)² (7)

In the formula A_ria、A_ricRespectively the actual projection area of the damage surface of the concrete cone of the longitudinal rib under the condition of considering the influence of the edge distance and the calculated projection area without considering the influence of the edge distance under the condition of tension at the joint_tThe design value is the tensile strength of the concrete.

S6, judging whether N is satisfied_rib≥F_kN, if the condition is satisfied, proceeding to the next step, if not, returning to S4-S5, re-determining the anchoring length l of the nut 1_aAnd the total length l of the nut 1_a1Until the condition is satisfied.

S7, determining the structure and the annular inner diameter D of the vertically-attached U-shaped reinforcing steel bar 3_vrWherein D is_vr≥2.5d_ad。

Determining the area A of the vertically additional U-shaped reinforcing bar 3 according to equation (8)_adAnd diameter d_ad；

In the formula: f. of_adFor the design value of the yield strength of the vertical additional U-shaped steel bars 3, m is the number of the vertical additional U-shaped steel bars 3, and 8, 2N are taken when 4 vertical additional U-shaped steel bars 3 are arranged_ribA safety reserve increased by a factor of 1 is considered.

S8, determining the length l of the vertically attached U-shaped reinforcing steel bar 3 extending out of the bottom of the restraint ring 22 of the bottommost restraint device 2 according to the formula (9)_adAnd determining the total length l of the vertically additional U-shaped reinforcing steel bar 3_ad1；

l_ad1＝l_ad+d_ad+l_a (9)。

In the formula d_adThe diameter of the vertically attached U-shaped reinforcing steel bar 3.

And S9, determining the structure of the horizontal additional channel-shaped reinforcing steel bar 4. The diameter of the horizontal additional channel-shaped reinforcing steel bars 4 is the same as that of the vertical additional U-shaped reinforcing steel bars 3, the horizontal additional channel-shaped reinforcing steel bars 4 are arranged at equal intervals along the vertical direction, the interval between the adjacent horizontal additional channel-shaped reinforcing steel bars 4 is not more than 100mm, and the number of the horizontal additional channel-shaped reinforcing steel bars 4 is not less than three. Wherein the topmost horizontally additional channel-shaped reinforcement bar 4 is arranged between the top first and second restraining means 2, most preferably the topmost horizontally additional channel-shaped reinforcement bar 4 is arranged in the middle between the top first and second restraining means 2, 2.

And S10, determining the structure of the horizontal additional trapezoidal steel bar 6. The diameter of the horizontal additional trapezoidal steel bar 6 is the same as that of the horizontal additional channel-shaped steel bar 4. Similarly, the horizontal additional trapezoidal steel bars 6 are arranged at intervals in the vertical direction, and the distance between the adjacent horizontal additional trapezoidal steel bars 6 is the same as that between the adjacent horizontal additional channel-shaped steel bars 4.

And S11, determining the structure of the U-shaped bottom reinforcing steel bar 9. The area A of the U-shaped bottom reinforcing bar 9 in S11 is determined according to the formula (11)_uAnd diameter d_u. Inner diameter D of annular end part of U-shaped bottom reinforcing steel bar 9_ufNot less than 2.5d_u. For convenient cross placement of the U-shaped bottom reinforcing bars 9, the inner diameter D of the annular end parts of the two U-shaped bottom reinforcing bars 9_ufShould be greater than 2d_u. When the fixing, the horizontal included angle between the U-shaped bottom reinforcing steel bars 9 and the thickness direction of the wall body is not less than 45 degrees.

In the formula f_uyThe design value of the yield strength of the U-shaped bottom reinforcing steel bar 9 is obtained; j is the number of limbs of the U-shaped bottom reinforcing steel bars 9, 2 are taken as one U-shaped bottom reinforcing steel bar 9, and 4 are taken as two U-shaped bottom reinforcing steel bars 9; 0.7 is a reduction factor of the strength in consideration of the installation angle.

And S12, removing the bolt 24, opening the restraint device 2, sleeving the key groove ring 21 outside the nut 1, closing the two key groove rings 21 and the two restraint rings 22, and fixing the two key groove rings 21 and the two restraint rings 22 by using the bolt 24, so that the restraint device 2 is installed outside the nut 1.

S13, passing the vertically additional U-shaped reinforcing bar 3 through the criss-cross bar 23 and binding with the restraining means 2. The number of the connecting points of each vertical additional U-shaped steel bar 3 and each restraint device 2 is not less than 1.

And S14, vertically installing the nut 1 with the restraint device 2 and the vertically attached U-shaped steel bar 3 in the longitudinal rib 7 of the wall body.

And S15, binding the horizontal additional groove-shaped reinforcing steel bars 4 and the horizontal additional trapezoidal reinforcing steel bars 6 with the vertical additional U-shaped reinforcing steel bars 3 and the wall reinforcing mesh 5 respectively to form the reinforcing steel bar framework.

And S16, the U-shaped bottom reinforcing steel bars 9 pass through the crossed bars 23 of the restraint devices 2 at the bottom and are bound with the wall reinforcing mesh 5 at the corresponding side.

And S17, pouring concrete, demolding and forming, and finally forming the embedded nut connecting node on the top of the prefabricated wall.

Specifically, taking a certain longitudinal rib hollow wallboard as an example, the dimension of the longitudinal rib hollow wallboard is as follows: wall length l_w5.4m, wall height h_w2.7m, wall thickness t_wThe diameter is 0.2m, a through cavity is adopted, and the cavity rate is 35.7%; the product is produced by steel flat die without chute and facing, and the demoulding area is 5.4x 2.7-14.58 m²(ii) a C40 concrete is adopted, and the design value f of compressive strength_c19.1 Mpa. The thickness c of the prefabricated wall steel bar protection layer is 15mm, and the minimum width b of the longitudinal rib at the joint of the nut is set_ribIs 150 mm. Density rho 25kN/m of concrete material³. Yield strength design value f of HPB300 steel bar_y300Mpa, yield strength design value f of HRB400 steel bar_y360Mpa, yield strength design value f of Q345 steel bar_y＝345Mpa。

S1, according to the volume V of the prefabricated wall board, the density rho of the concrete material and the cavity rate r_VCalculating the standard value G of the self-weight of the wallboard_mk47 kN; according to calculation and judgment, the stress of the nut 1 is the largest under the non-demolding lifting working condition, so that the load increase coefficient K is calculated to be 4.5 according to the formula (1).

S2, determining the standard value G of the self weight of the wallboard according to S1_mkLoad increase coefficient K, calculating the effect of the increase of the load 1Total load under load F_k＝70kN。

S3, the nut 1 is made of Q390 steel, 2 points are symmetrically arranged, 35kN of external force and diameter d of each external force can be obtained_r＝20mm。

The constraint device 2 adopts Q390 phi 10 steel bars, the spacing s is 100mm, and the design value f of the yield strength of the steel is determined_jy345MPa, designed compressive strength value f_c19.1Mpa, the cross-sectional area a of the confinement ring 22_j＝75mm². The width of the restriction device 2 is b_str120mm, and restraint device 2 top is 15mm below the prefabricated wall body top.

The bonding anchoring strength τ of the nut 1 was calculated from the equations (3) and (4)_uBasic anchoring length l ═ 3.07MPa_abSatisfy l_ab28,/d, final l_abTake 560 mm.

The height of the key groove ring 21 was designed to be 40mm, and the chamfer of the outer circumferential edge portion of the key groove ring 21 was 60 °. The diameter of the cross bar 23 is taken to be 10 mm.

S4, calculating the anchoring length l of the nut 1 according to the formula (5)_a340 mm. Determination of the overall length of the nut 1: l_a1380mm, meeting the design requirement.

S5, calculating the breaking strength N of the longitudinal rib concrete cone under the tension state at the joint according to the formula (7)_rib37.75kN, where the actual projected area A_ricAccording to a partial conservative approach_w×b_rib＝150mm×200mm。

S6, judging the breaking strength (N) of the concrete cone with longitudinal ribs_rib＝37.75kN)＞(F_k70/2-35 kN), the discrimination condition is satisfied, and the next step is proceeded.

S7, determining the structure of the vertically-attached U-shaped reinforcing steel bar 3 with the annular inner diameter D_vr≥2.5d_ad。

S8, determining the length l of the vertically attached U-shaped reinforcing steel bar 3 extending out of the bottom of the restraint ring 22 of the bottommost restraint device 2 according to the formula (9)_ad215mm and determines the total length l of the vertically additional U-shaped reinforcement bar 3_ad1＝570mm。

S9, adopting phi 10 steel bars of HRB400 as the horizontal additional channel-shaped steel bars 4; 4 groups are arranged, and the distance between each group and the top of the wall is 60mm, 160mm, 260mm and 340 mm.

S10, determining the structure of the horizontal additional trapezoidal steel bars 6: the material, the diameter and the position interval are the same as those of the horizontal additional groove-shaped steel bar 4, the length of the platform section is 60mm, and the vertical additional U-shaped steel bar 3 is convenient to bind.

S11, determining the area A of the U-shaped bottom reinforcing steel bar 9 according to the formula (9) by adopting the HPB300 steel bar as the U-shaped bottom reinforcing steel bar 9_u＝106mm²Diameter d_u12mm, annular end inner diameter D_uf30 mm. When the fixing, the horizontal included angle between the U-shaped bottom reinforcing steel bars 9 and the thickness direction of the wall body is not less than 45 degrees.

The above examples are only for describing the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, and various modifications and improvements made to the technical solution of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.