RU2713826C2 - Method for manufacturing of prefabricated-monolithic reinforced-concrete resting on contour slabs of floors with round cavities using non-extractable cardboard-polyethylene cavities - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to construction. Method of fabrication of assembly-monolithic reinforced-concrete resting on contour slabs of floors with round cavities using non-extractable cardboard-polyethylene cavities makes device of trays for concreting parts (modules) of lower flange of floor slabs (prefabricated part of slabs). Reinforcement modules are made with non-extractable cavities installed inside the reinforcement frame. Concrete pads are laid in trays for reinforcement modules, concrete plates are poured into concrete pans, reinforcing modules with non-extractable cavities are placed in trays with filled concrete. Prefabricated parts of plates are removed from trays with finished bottom shelf, which further serves as formwork for laying concrete of monolithic part of plate. Delivery of assembly parts of plates to the construction site, laying of assembly parts of floor slabs in working position with connection of joints of elements of floor slabs by means of additional reinforcement rods, laying pipes for laying of utility networks, concrete pouring of monolithic part of slab. Non-removable cardboard-polyethylene pockets are made of round-oval cardboard tubes coated with water-insulating polyethylene film with thickness of 0.045 mm. Cavities are square or rectangular in plan, closed by cut corners by cardboard-polyethylene covers. At that reinforcement of plates is performed similarly to reinforcement of caisson plates with addition of reinforcement of lower flange of plates.

EFFECT: technical result is reduction of consumption of reinforcement, concrete and reduction of weight of plates with preservation of bearing capacity of slab.

1 cl, 5 dwg, 1 tbl

Description

The technical field to which the invention relates: construction.

The prior art. The invention is directed to reducing the weight of precast-monolithic reinforced concrete floor slabs, through the use of non-recoverable cardboard-polyethylene

void formers. The closest analogue of the invention is a method in which a precast-monolithic reinforced concrete floor slab is made using non-removable plastic balls-hollow formers placed in cells formed by reinforcement [1]; a positive feature of this method is the absence of the need to use formwork for the manufacture of slabs at a construction site; The disadvantage of this analogue is the greater consumption of concrete and reinforcement, and, consequently, the greater weight of one square meter of the slab compared with the invention. Another analogue of the proposed invention is a patent for invention No. 2634156 “Method for the continuous production of monolithic reinforced concrete hollow core slabs based on the contour using non-removable tubular cardboard-polyethylene hollow formers” [2], the disadvantage of this analogue is the need to use formwork at a construction site. In addition, this method relates to the previous monolithic class of reinforced concrete floor slabs.

Disclosure of the invention.

Currently, the development of technology allows the production of precast-monolithic floors in various ways [3]. This is the use of various inserts in the slab of light materials, the installation of non-removable polyethylene and plastic hollow formers, but all previously developed methods are inferior to the method proposed in this application for the invention.

The essence of the invention lies in the fact that to reduce the weight of prefabricated monolithic floor slabs, cardboard-polyethylene hollow formers made of round-section cardboard tubes coated with a waterproofing polyethylene film of 0.045 mm thickness are rectangular or square in plan, closed by cut corners of cardboard-polyethylene covers; reinforcement of prefabricated monolithic plates is performed similarly to the reinforcement of caisson plates with the addition of reinforcement for the lower shelf.

The method has such positive properties of prefabricated-monolithic structures as assembling a unified reinforcing module with simultaneous installation of non-removable cardboard-polyethylene hollow formers in the reinforcing cage and concreting of the lower shelf of the slab in workshops or at a specially prepared site on the construction site; lack of the need for formwork devices for the manufacture of plates at a construction site [4].

Recommended parameters of the materials for the manufacture of the hollow core are given in table 2.1. The thickness of the prefabricated monolithic slab, the dimensions of the bearing cross beams, the thickness of the lower and upper shelves, the diameter of the hollow core, the thickness of the cardboard and polyethylene are taken depending on the length of the design span, design loads and permissible deformations, as well as on the basis of experimental data. The vertical position of the void formers is determined by calculation. The distance between the void formers is determined by the project. Concrete classes, working and structural reinforcement are determined by the project. Concrete for precast-monolithic floor slabs can be made on ordinary or prestressed cement.

Description of the drawings.

In FIG. Figure 1 shows a fragment of the plan of a precast-monolithic slab resting along the contour with the location of cardboard and polyethylene pipes of an unrecoverable core 1, holes in the core for concrete 2, cross load beams 3 of width δ, outer dimensions of the core a, b, section A-A (location fittings conditionally not shown). In FIG. 2 shows: a section of a fragment of a slab A-A of height h, cardboard-polyethylene pipes of a non-removable core former 1, a reinforcing cage 4 of cross bearing beams, reinforcing meshes of the shelves of the upper 5 and lower 6, rods 7 connecting the upper and lower shelves of the slab, precast concrete 8 cast concrete 9 and seam 10 between them, the outer dimension of the core former a. In FIG. Figure 3 shows the location of sections B-B and B-B, a plan of a hollow core made of pipes 1 and corner caps 11, also shows holes 2 in the core between pipes for the convenience of laying concrete and installing reinforcing bars connecting the upper and lower shelves of the slab, the outer dimensions of the core a and b. In FIG. 4 shows a cross-section of a bore-forming agent B-B, openings between the concreting pipes 2, the location of the corner covers 11, the outer dimension of the void forming agent a, along section B-B and the outer diameter of the void-forming pipe ∅. In FIG. 5 shows a cross-section of a core former B-B with an arrangement of corner covers 11 and polyethylene 12 from the outer surface of a cardboard pipe, the outer dimension of a core former b along section BB and an outer diameter of a tube of a core former ∅.

The implementation of the invention

1. On the basis of the project for the calculation and design of precast-monolithic reinforced concrete floor slabs, the dimensions of the pathogen a, b, the outer diameter ∅, and the thickness of the cardboard pipe δ _{k are} determined.

2. At the manufacturer's factory, upon the request of the builders, cardboard-polyethylene core-holders are made in accordance with the project.

3. In the factory or on the construction site, in a specially prepared place, the reinforcement of the plate is assembled in the form of unified design modules (similar to reinforcing coffered plates with the addition of reinforcement of the lower shelf), at the same time cardboard-plastic hollow formers are installed inside the reinforcement cage, which are fixed with reinforcing mesh, 1-1.5 mm thick knitting wire and plastic clips. To perceive the transverse forces near the supports and to prevent the plates from being pushed through the supports from the pressure of the walls, the hollow breakers break off at a distance from the supports in accordance with the design, but not less than the thickness of the plate.

4. The pallet for concreting the bottom shelf of the slab is made in such a way that it is possible to make prefabricated parts of the slab of the required design dimensions.

5. Concrete is poured into the pallet with a thickness determined by the project of approximately 8–12 cm, depending on the span and the height of the cross-section of the floor slab.

6. Concrete pads are placed in concrete to fix the bottom reinforcement in the design position, with the aim of forming a protective concrete layer of reinforcement.

7. A pre-assembled module consisting of a reinforcing cage and hollow formers is laid in a pallet with poured concrete on concrete pads.

8. After gaining the design strength of concrete (if it is necessary to accelerate the building up of concrete, heating is organized or additives are added that accelerate setting), the prefabricated part of the slab is removed from the pallet with the finished lower shelf, which later serves as the formwork for laying concrete of the integral part of the slab.

9. Prefabricated parts of the slab are delivered to the construction site and placed in the working position, with the joints of the elements of the floor slabs connected with additional reinforcing bars.

10. To fix the horizontal design mark of the bottom of the lower shelf, telescopic racks are installed.

11. If necessary, additional welding work is carried out, and the core former must be protected from damage (fire).

12. Inside the reinforcing cage, pipes are laid for laying various engineering networks.

13. The concrete is cast in the monolithic part of the floor slab.

14. Concrete is maintained until it reaches its design strength in accordance with weather conditions and the design of the work.

15. In the process of manufacturing a prefabricated monolithic hollow core slab, the quality of the materials used and the quality of the work are constantly checked in accordance with the technological map with the preparation of acts for hidden work.

The proposed method for the manufacture of prefabricated monolithic floor slabs based on the contour can reduce the cost of production of slabs, reduce the consumption of reinforcement, concrete and reduce the weight of the slab to 40%.

Claims (1)

A method of manufacturing precast-monolithic reinforced concrete slabs based on the contour of slabs with round voids using non-removable cardboard-polyethylene hollow formers, including the device of pallets for concreting parts (modules) of the lower shelf of floor slabs (prefabricated part of slabs), the manufacture of reinforcing modules with non-removable hollow formers installed inside reinforcing cage, laying concrete pads for reinforcing modules in pallets, pouring the bottom slabs into concrete pallets, laying pallets with reinforced concrete poured concrete with non-removable core formers, removal of prefabricated slabs from the pallets with the finished lower shelf, which subsequently serves as formwork for laying the monolithic part of the slab, delivery of prefabricated slabs to the construction site, laying of prefabricated parts of floor slabs in working position with connecting joints of elements of floor slabs using additional reinforcing bars, laying pipes for laying utility networks, pouring concrete on the monolithic part of the floor slab ; characterized in that to reduce the weight of the slabs, non-removable cardboard-polyethylene hollow core from round-section cardboard tubes coated with a waterproofing polyethylene film of 0.045 mm thickness, square or rectangular hollow core, closed at cut corners with cardboard-plastic covers are used; plate reinforcement is performed similarly to the reinforcement of caisson plates with the addition of reinforcement for the lower shelf of plates.

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