CN104929290B - Large-span steel-reinforced concrete orthogonal-diagonal lattice hollow floor system and preparation method thereof - Google Patents

Abstract

The invention relates to a large-span reinforced concrete orthogonal oblique fasting floor. The perimeter of the building floor is an isosceles triangular grid, the middle is a square fasting grid at an angle of 45° along the periphery, and the size of the right-angled side of the surrounding isosceles triangle is a The relationship between the hypotenuse length a ₁ of the isosceles triangle is a=a ₁ × sin45°, that is, after the surrounding grid a ₁ is determined, the size of the internal square grid a along the 45° direction is determined. When the length L _x of the building and its span L When the ratio of _y is greater than 1.5, adopt the orthogonal oblique fasting grid layout, which can change the floor from one-way force transmission to two-way force (45° direction), so as to achieve uniform force on the floor, save building materials and reduce Compared with the traditional long-span frame structure, the project cost can be saved by 25%-30% in concrete and 20%-25% in steel materials on the orthogonal obliquely placed vierendeel floor; , the empty belly position is the air-conditioning and pipeline equipment layer of the floor, which greatly saves the thickness of the floor.

Description

Large-span reinforced concrete orthogonal inclined hollow floor and its manufacturing method

technical field

The present invention relates to a reinforced concrete vierendeel floor with a narrow and elongated plane, in particular to a kind of floor which is suitable for the ratio L _x /L _y of the floor length (L _x ) to the span size (L _y ) > 1.5 or The invention relates to a large-span reinforced concrete orthogonal slanting hollow floor and a manufacturing method thereof, which belong to the technical field of construction.

Background technique

Reinforced concrete structure engineering has been restricted by the traditional structural system for a long time. For floors with a span of (18m-30m), the only solution is the reinforced concrete primary and secondary beam structure, as shown in Figure 1. The dimension L _x =6×7.2m=43.2m, the short direction is the span direction L _y =3×7.2m=21.6m, the floor area is 43.2m×21.6m=933.12m ² with primary and secondary beams, the floor The service load is 4kN/m ² , the floor concrete is marked C30, the amount of concrete used for the design is 40.5cm/m ² , the amount of concrete for each floor is 378m ³ , the steel for the floor is 122kg/m ² , and the steel for each floor is 113.8T . The traditional structure not only consumes a lot of building materials, but also has a high construction cost. Its 21.6m reinforced concrete girder (700×1800) has become a real "fat beam". Not only that, it also greatly increases the thickness of the floor. , the thickness of the floor is 1800+700+20=2700, which is the height of one floor of a conventional building. This structure violates the basic principles of energy saving and emission reduction.

Due to the constraints of traditional structures, multi-storey long-span frame structures are seldom used, and the so-called advanced method, that is, prestressed concrete girders, can be reduced in height (600×1500), that is, the thickness of each layer is reduced by 0.3m. The increase in stress cost has not reduced the project cost, and there is no innovation based on the structural system. When the span L=(18m-30m) multi-storey floor, almost no one cares about it.

The three principles of circular economy in China's economic construction (energy conservation and emission reduction, sustainable development, and land conservation to promote ecological civilization) require large-span buildings to be multi-storey. The inventor proposed "Reinforced Concrete Shear Key Two-Way Hollow slab" (ZL97200102.6) is a hollow slab floor composed of reinforced concrete hollow beams with orthogonal grids, so that the original multi-storey (2-4 floors) long-span (18m-30m ) The structural system of public and industrial buildings can be changed with fat beams and fat columns. The original patent no matter whether the plan form of the floor is square or rectangular, and the ratio of the long side (L _x ) to the short side (L _y ) is less than or greater than 1.5, all adopt Orthogonal and vertical grids, that is, the grid intersecting nodes are orthogonal to each other (90 ⁰ ), and the surrounding beams and supporting sides are also orthogonal (90 ⁰ ). This kind of orthogonal grid floor, when the The square roof (L _x /L _y =1) bears the most uniform force, each accounting for 50%. Generally, the orthogonal grid is applied to the floor with L _x /L _y <1.5. When L _x /L _y =1.5 , 70% of the floor load is transmitted to the support from the short direction (L _y ), and only 30% is transmitted to the support point from the long direction. When L _x /L _y =2, the short direction load reaches 87.5%, and The force transmission is only 12.5%, and the force is extremely uneven and unreasonable. When the planar dimension of the floor is L _x /L _y > 1.5 or larger and narrow and elongated, the use of orthogonal and vertical grids will result in extremely uneven stress on the floor, resulting in waste of materials and increased costs.

Contents of the invention

The problem to be solved by the present invention is to provide a large-span reinforced concrete orthogonal slanting hollow floor to overcome the defects of the prior art and achieve the following objectives:

1) It can be applied to narrow and elongated floor plan where the ratio L _x /L _y of the long side dimension L _x to the span dimension L _y is greater than 1.5.

2) The floor can be changed from one-way force transmission to two-way force (45° direction), so as to achieve uniform force on the floor, save building materials and reduce project cost, save 25%-30% of concrete, and steel Save 20%-25%.

3) The large-span floor is formed by placing the hollow beams perpendicularly and obliquely. The fasting section is the air-conditioning and pipeline equipment layer of the floor, which greatly saves the thickness of the floor.

4) Provide a method for making a large-span reinforced concrete orthogonal oblique hollow floor.

In order to solve the above technical problems, the present invention adopts the following technical solutions: a large-span reinforced concrete orthogonal slanted hollow floor, which is characterized in that: the perimeter of the building floor is an isosceles triangular grid, and the middle is a square hollow with 45 ^° angles along the periphery grid.

An optimization scheme, the size a of the right-angled side of the surrounding isosceles triangle and the length a ₁ of the hypotenuse of the isosceles triangle have a relationship of a=a ₁ × sin45°, that is, after the surrounding grid a ₁ is determined, the internal square grid a along the 45° direction The size is also fixed.

In an optimization scheme, the building floor is a narrow and elongated plane with a ratio L _x /L _y >1.5 of the long side (L _x ) to the short side (L _y is the span).

Based on the above-mentioned large-span reinforced concrete orthogonal obliquely placed hollow floor, the present invention provides a method for manufacturing a large-span reinforced concrete orthogonally inclined hollow floor, characterized in that: the manufacturing method includes the following steps:

(1) Lay out the wires according to the drawings and set up supports;

(2) Set up the lower chord and shear key formwork at the floor support elevation;

(3) Binding the lower chord and shear key steel bars and checking and accepting the steel bars;

(4) Pouring concrete to the top of the shear key;

(5) After the concrete strength reaches 80%, install the upper chord grid and the formwork of the slab at the bottom of the upper chord on the upper part of the shear key;

(6) Binding steel bars;

(7) Pouring concrete;

(8) After curing, a long-span reinforced concrete orthogonal slanted hollow slab floor is formed.

Another manufacturing method of the above-mentioned large-span reinforced concrete orthogonal obliquely placed hollow floor is characterized in that: the manufacturing method includes the following steps:

(1). Set up the support according to the construction drawing;

(2). Install formwork and steel bars for the upper and lower chords and shear keys of the hollow floor according to the construction drawings;

(3). At the shear key (the intersection position of the upper chord), leave a hole for pouring concrete. From this hole, the concrete is cast in place, from the lower chord to the shear key and then to the upper chord and the upper chord grid panel.

The present invention adopts the above technical scheme, and compared with the prior art, it has the following advantages: when the ratio L _x /L _y of the floor length to the short direction is >1.5, the orthogonal hollow beams are placed at 45° around the perimeter, The 45° arrangement around the hollow beams forms an orthogonal obliquely placed reinforced concrete hollow floor, which can change the floor from one-way force transmission to two-way force (45° direction), so as to achieve uniform force on the floor and save construction Materials and reduce project cost, saving 25%-30% in concrete and 20%-25% in steel; large-span floors are formed by vertically inclined hollow beams, and the hollow parts are the air-conditioning and pipelines of the floor The equipment floor greatly saves the thickness of the floor.

The present invention will be further described below in conjunction with drawings and embodiments.

Description of drawings

Accompanying drawing 1 is the structural arrangement diagram of conventional reinforced concrete primary and secondary beams or frame structure system;

Accompanying drawing 2 is the grid layout diagram of the hollow beam of reinforced concrete orthogonal oblique laying hollow floor in the embodiment of the present invention;

Accompanying drawing 3 is the plan view of the hollow position of the lower left floor of accompanying drawing 2;

Accompanying drawing 4 is A-A sectional view among accompanying drawing 3;

Accompanying drawing 5 is the sectional view of 1-1 node in accompanying drawing 4;

Accompanying drawing 6 is the sectional view of B-B node in accompanying drawing 4.

detailed description

In the embodiment, the large-span reinforced concrete obliquely lays the fasting floor, the perimeter of the building floor is an isosceles triangular grid, the middle is a square fasting grid along the 45 ^° angle around the perimeter, and the dimension a of the right-angled side of the surrounding isosceles triangle is equal to that of the isosceles The length a ₁ of the hypotenuse of the triangle is a=a ₁ ×sin45°, that is, after the surrounding grid a ₁ is determined, the size of the internal square grid a along the 45° direction is also determined.

Taking the floor shown in Figure 1 as an example to describe in detail, there is a reinforced concrete girder every 7.2m in the length direction, a secondary beam every 3.6m, and concrete connecting beams are connected with the girders around the perimeter to form a 43.2m×21.6 The large-area floor of m=933.12m ² , this traditional structure causes high engineering costs and hinders the development of multi-storey and long-span construction projects. The specific embodiment is to change the structure shown in Fig. 1 to the structure plane shown in Fig. 2, that is, to place the empty belly floor vertically and obliquely.

The large-span reinforced concrete orthogonal oblique hollow floor is manufactured according to the following steps:

(1) Lay out the wires according to the drawings and set up supports;

(2) Set up the lower chord and shear key formwork at the floor support elevation;

(3) Binding the lower chord and shear key steel bars and checking and accepting the steel bars;

(4) Pouring concrete to the top of the shear key;

(5) After the concrete strength reaches 80%, install the upper chord grid and the formwork of the slab at the bottom of the upper chord on the upper part of the shear key;

(6) Binding steel bars;

(7) Pouring concrete;

(8) After curing, a long-span reinforced concrete orthogonal slanted hollow slab floor is formed.

As shown in Figure 2, the surrounding (L _x , L _y ) direction adopts concrete isosceles triangular fasting grids, and the internal square grids are arranged side by side along the direction of 45° on both sides. For example, the above floor plan (933.12m ² ) consists of 36 The isosceles triangle and 126 positive direction grids form a rhombus, which is not only the force-bearing member of the floor, but also the ceiling shape of the floor.

As shown in Figure 3, the cross section is the section of the internal shear key of the floor, the pentagon is the section of the corner shear key, and the hexagon is the section of the peripheral shear key.

As shown in Fig. 4, the reinforced concrete vertical oblique open-web floor is composed of cast-in-place concrete upper chords (including panels) lower chords and shear keys, and its square grid size a is the size of the right-angled side of _an isosceles triangle sin45°, such as a ₁ =3600, a=2545.5, in order to ensure the shear stiffness of the shear key, the ratio of net height (h ₀ ) to net width (B) h ₀ /B≤1, the hollow ratio of the floor is very large, Generally between 80% and 85%, the self-weight of the floor structure is greatly reduced while ensuring the three-dimensional force of the floor. h is the thickness of the hollow floor structure, generally h = (1/25-1/30) L, as shown in Figure 4, h = 21600/25 = 850, which is 60%-53% lower than the height of the reinforced concrete girder.

As shown in Figure 5, it is a cross-shaped reinforced concrete shear key section size and reinforcement structure, which is a key component to ensure that the upper chord (including the slab) and the lower chord of the floor work together.

As shown in Figure 6, it is a side view of the hollow beam around the concrete hollow floor. The whole reinforced concrete hollow perimeter is supported _on the surrounding edge beams according to the grid a1, and the hollow section of the floor can be used as a shutter on the building.

The specific construction methods are as follows (1) Lay out the lines according to the drawings and set up supports;

(2) Set up the lower chord and shear key formwork at the floor support elevation;

(3) Binding the lower chord and shear key steel bars and checking and accepting the steel bars;

(4) Pouring concrete to the top of the shear key;

(5) After the concrete strength reaches 80%, install the upper chord grid and the formwork of the slab at the bottom of the upper chord on the upper part of the shear key;

(6) Binding steel bars;

(7) Pouring concrete;

(8) After curing, a long-span reinforced concrete orthogonal slanted hollow slab floor is formed.

The mechanical model of the reinforced concrete hollow grid floor of a large-span construction project is a sandwich panel considering shear deformation, and the "board" can be divided into "two-way slab" and "one-way slab", such as reinforced concrete floor slab , when the ratio of the long side L _x to the span L _y is greater than 2 (L _x /L _y ≥ 2), it is defined as a one-way slab. During design, the reinforcement shall be reinforced according to the internal force of the short _span (L _{y )} , and the reinforcement shall only be reinforced according to the structure in the long direction, as shown in Fig _. L _y =43.2/21.6=2, how to distribute the floor load P in the two directions (x, y) can be expressed by the following formula: P _x =P/(1+n ³ ) and P _y =【1-(1 /1+n ³ )】p means, n is the length ratio, the ratio of Figure 1 and 2 is n=2, then P _x =p/9=0.125p, P _y =[1-0.125]p=0.875p, floor 90% of the cover load is transmitted along the short span, and only 10% is transmitted along the long direction. For example, when n=5, 99.2% of the internal force is distributed in the short direction, and 0.8% is distributed in the long direction. Slab floor is also unreasonable, adopts the structural form of the present invention this moment, will reach safe, reasonable, advanced, economical requirement.

Under the same span and the same use load, the concrete hollow sandwich slab floor of the present invention is compared with the traditional structure: the concrete saves 25%-30%, the steel saves 20%-25%, and the reinforced concrete orthogonal structure is adopted for the plane floor in Figure 1 The amount of concrete used for the slanted hollow floor is 21.5cm/m ² , a drop of 19cm/m ² , and the amount of steel is 71.5kg/m ² , a drop of 50.5kg/m ² . The new floor system has met the requirements of the three principles of the national circular economy , so that the floor is evenly stressed, saving building materials and engineering costs.

The following production methods can also be used for construction:

(1). Set up the support according to the construction drawing;

(2). Install formwork and steel bars for the upper and lower chords and shear keys of the hollow floor according to the construction drawings;

(3). At the shear key (the intersection position of the upper chord), leave a hole for pouring concrete. From this hole, the concrete is cast in place, from the lower chord to the shear key and then to the upper chord and the upper chord grid panel.

Those skilled in the art should realize that the above-mentioned specific embodiments are only exemplary, and are intended to enable those skilled in the art to better understand the content of the present invention, and should not be construed as limiting the protection scope of the present invention. The improvements made in the technical solution of the invention all fall into the protection scope of the present invention.

Claims (2)

1. The large-span reinforced concrete orthogonal oblique empty-belly floor is characterized in that: the perimeter of the building floor is an isosceles triangular grid, and the middle is a square empty-belly grid at an angle of 45° along the periphery; The size a of the right-angled side of the surrounding isosceles triangle and the length a ₁ of the hypotenuse of the isosceles triangle are a=a ₁ ×sin45°; The building floor is a narrow and elongated plane with the ratio of the long side (L _x ) to the short side (L _y ) L _x /L _y >1.5; The large-span reinforced concrete orthogonal oblique hollow floor is manufactured according to the following steps: (1) Lay out the wires according to the drawings and set up supports; (2) Set up the lower chord and shear key formwork at the floor support elevation; (3) Binding the lower chord and shear key steel bars and checking and accepting the steel bars; (4) Pouring concrete to the top of the shear key; (5) After the concrete strength reaches 80%, install the upper chord grid and the formwork of the slab at the bottom of the upper chord on the upper part of the shear key; (6) Binding steel bars; (7) Pouring concrete; (8) After curing, a long-span reinforced concrete orthogonal slanted hollow slab floor is formed. 2. Large-span reinforced concrete orthogonal oblique empty-belly floor, characterized in that: the perimeter of the building floor is an isosceles triangular mesh, and the middle is a square empty-web mesh at an angle of 45° along the periphery; The size a of the right-angled side of the surrounding isosceles triangle and the length a ₁ of the hypotenuse of the isosceles triangle are a=a ₁ ×sin45°; The building floor is a narrow and elongated plane with the ratio of the long side (L _x ) to the short side (L _y ) L _x /L _y >1.5; The method for making the large-span reinforced concrete orthogonal obliquely placed hollow floor includes the following steps: (1) Set up the support according to the construction drawing; (2) Install the formwork and steel bars of the upper and lower chords and shear keys of the hollow floor according to the construction drawings; (3) At the shear key at the intersection position of the upper chord, a hole for pouring concrete is left, from which the concrete is poured in place, from the lower chord to the shear key to the upper chord and the upper chord grid panel, and is formed in one pour.