Reinforced concrete column base

Abstract

This utility model relates to the construction of a building and / or its supporting structures made of reinforced concrete using concrete poured into permanent formwork. It can be used on-site or in the production of precast-monolithic reinforced concrete foundations. The technical result consists of increased strength and rigidity of the column base, as well as reduced labor intensity, labor costs, and construction time for the reinforced concrete foundation. The metal formwork consists of a thin-walled metal tube with shortened anchor stud bolts equipped with high nuts and elastic washers, a support and thrust ring of the metal tube with openings for the anchor stud bolts and self-anchoring spacer bolts, welded seams, and high-strength structural concrete.

Description

[0001] The utility model relates to the construction of a building and / or its supporting structures made of reinforced concrete using concrete pouring into permanent formwork; it can be used at a construction site or in the conditions of production of a precast-monolithic reinforced concrete foundation.

[0002] A design of permanent formwork is known for the manufacture of the main elements of buildings and structures, containing flat steel fiber concrete slabs connected by fasteners / Patent RU 2652770, IPC E04 B 2 / 86; Permanent steel fiber concrete formwork / Dorf V.A., Krasnovsky R.O., Krol I.S. and others; declared 17.03.2017, published 28.04.2018, Bulletin No. 13 [1].

[0003] However, flat sheets of permanent formwork of the known technical solution cannot be used in the manufacture of load-bearing structures of a circular cross-section building, including columns and sub-columns of a reinforced concrete foundation.

[0004] A design of permanent formwork for monolithic concrete or reinforced concrete made of inorganic glass is known, including a set of elements and parts for forming the shape of the structure, wherein the enclosing shell is made in the form of a flat wall made of inorganic glass up to 150 mm thick / Patent RU 2668669, IPC E04 B 2 / 86. Permanent formwork for monolithic concrete and reinforced concrete made of inorganic glass (variants) / Gresh K.O.; declared 11.01.2018, published 02.10.2018, Bulletin No. 28 [2] – adopted as a prototype.

[0005] However, the existing technical solution cannot be successfully applied to the production of a circular column base for a precast-monolithic foundation as part of a reinforced concrete element; in this case, the glass formwork serves only as a protective barrier.

[0006] The essence of the utility model lies in improving the design of a column base, a precast foundation, using sections of thin-walled metal pipe as permanent formwork; in simplifying the calculation of the bearing capacity and design of a column base, manufactured in the form of a compressed tube-concrete element; in reducing the labor intensity, labor costs and time of construction of a precast-monolithic foundation; in increasing the efficiency of concrete and metal consumption in the manufacture of a column base; in the use of structural monolithic concrete of higher compressive strength classes; in simplifying the care of concrete during the monolithic casting of the column base and its curing for strength gain.

[0007] Technical result – increased strength and rigidity of the column base.

[0008] The technical result is achieved in that the reinforced concrete column base, characterized in that it contains permanent formwork formed by a section of a thin-walled metal pipe, the height of which is equal to the height of the column base, which is filled with structural concrete of increased compressive strength, and is equipped with stiffening elements welded to it with a one-sided weld along the support contour, is provided with a support steel ring in the upper part, and a thrust steel ring in the lower part, anchor stud bolts of the support steel ring, equipped with high nuts and elastic washers, are connected to the inner surface of the section of the thin-walled metal pipe by welded seams; the thrust steel ring is provided with through holes for passing self-anchoring spacer bolts and fixing the thin-walled metal pipe to the foundation slab, wherein the outer diameter of the support steel ring is equal to the diameter of the thin-walled metal pipe, and the inner diameter is equal to the diameter of the column;the inner diameter of the thrust steel ring is equal to the diameter of the metal pipe, and the outer diameter exceeds the pipe diameter by at least the amount required to accommodate the expansion bolts.

[0009] The design compressive strength of the structural concrete and pipe metal is taken into account for their combined operation as part of a reinforced concrete column base. The metal pipe section is assumed to be 1 to 6 mm thick; the required pipe metal thickness is based on the calculation results. The metal pipe section is made of electric-welded steel with the design resistance. .

[0010] The section of metal pipe is limited at the top of the column base by the foundation edge, and at the bottom by the foundation slab.

[0011] The butt weld of a thin-walled metal pipe and the fastening of anchor stud bolts are made with a double-sided weld, the thickness of the weld leg is

[0012] ,

[0013] whereq МТ – thickness of steel of a section of metal pipe, mm.

[0014] Required metal thickness ( ) permanent formwork is calculated using the equation

[0015] ,

[0016] where – the length of the pipe circumference at the middle of its thickness;

[0017] – the required cross-sectional area of ​​the permanent formwork metal is calculated using the equation

[0018] ,

[0019] where – longitudinal force on the foundation edge, kN,

[0020] And – coefficients of conditions for timely operation of concrete and metal;

[0021] And – calculated compressive strength of concrete and metal, MPa;

[0022] - cross-sectional area of ​​concrete in the pipe, mm 2 , calculated by the equation:

[0023] ,

[0024] where – an irrational number;

[0025] – radius of concrete cross-section in the pipe, mm;

[0026] – the length of the circumference of the pipe at the middle of its thickness, calculated using the equation

[0027] ,

[0028] where – an irrational number;

[0029] – average diameter of permanent formwork pipe.

[0030] The outer surface of the pipe metal, anchor stud bolts and anchor self-anchoring spacer bolts of the fixed column base are covered with bitumen insulation.

[0031] Brief description of drawings.

[0032] Fig. 1 shows a general view of permanent metal formwork for a reinforced concrete foundation column base under a steel column: 1 - steel column; 2 - stiffeners; 3 - anchor stud bolts; 4 - high nuts; 5 - elastic washers; 6 - support ring; 7 - thin-walled metal pipe, ; 8 - structural concrete; 9 - self-anchoring expansion bolts; 10 - thrust ring; 11 - foundation slab; 12 - one-sided weld; 13 - two-sided weld; 14 - foundation upper edge mark (-0.150 m); d кол – outer diameter of the column, mm.

[0033] Fig. 2 and 3 show the support ring of the column base (Fig. 2) and the thrust ring of the lower part of the column base (Fig. 3) (the symbols are shown in Fig. 1): d ОК and d УК – outer diameter of the support and, accordingly, thrust ring, mm; d О – diameter of holes for passing anchor bolts, mm.

[0034] The permanent metal formwork consists of a section of thin-walled metal pipe 7, made electric-welded from steel with a thickness of 1ё6 mm, filled with structural concrete 8. The thin-walled metal pipe 7 is equipped with a support ring 6 in the upper part, and a thrust ring 10 in the lower part, both rings are made of steel with a thickness of 10ё40 mm, which are welded to it with a one-sided weld 12. The inner diameter of the thrust ring 10 is equal to the inner diameter of the thin-walled metal pipe 7. The outer diameter of the thrust ring 10 is taken based on the condition of placing self-anchoring spacer bolts 9. The inner diameter of the support ring 6 is equal to the inner diameter of the steel column 1, and the outer diameter is equal to the inner diameter of the thin-walled metal pipe 7. Stiffening ribs 2, a total of eight pieces, are made of steel with a thickness of 10 mm.Four stiffening ribs 2 are welded to the thrust ring 10 and the thin-walled metal pipe 7, wherein their location is symmetrical relative to the center of the column. The remaining four stiffening ribs 2 are welded to the support ring 6 and the steel column 1, wherein their location is symmetrical relative to the center of the column. The height of the thin-walled metal pipe 7 is equal to the required height of the column base and is limited at the top by the foundation edge and at the bottom by the foundation slab 11. Shortened anchor stud bolts 3 of the support ring 6, equipped with tall nuts 4 and elastic washers 5, are attached to the inner surface of the section of thin-walled metal pipe 7 by welded seams. The thrust steel ring 10 is provided with through holes for passing self-anchoring spacer bolts 9 and securing the thin-walled metal pipe 7 to the foundation slab 11.

[0035] When performing a butt weld between a thin-walled metal pipe 7 and shortened anchor stud bolts 3, a double-sided weld 13 is provided. The outer surface of the pipe metal and the anchor fastenings of the column base are covered with bitumen insulation.

[0036] A section of thin-walled metal pipe filled with high-compressive strength structural concrete is used as permanent formwork for the sub-column of a precast-monolithic foundation.

[0037] The calculated compressive strength of the concrete and pipe metal is taken into account for their combined operation as part of a reinforced concrete column base. The metal pipe section is assumed to be 1 to 6 mm thick; the required metal thickness is based on the calculation results. The metal pipe section is made of electric-welded steel with the calculated resistance. , the outer surface of the pipe metal and the anchor fastenings of the column base are covered with bitumen insulation.

[0038] Shortened anchor stud bolts are welded to the inner surface of a section of thin-walled pipe, through which the load from the building's steel column is transferred.

[0039] Transfer of concentrated loads to the end of a section of thin-walled metal pipe filled with high-strength structural concrete is carried out through the formwork stiffening elements - through a support steel ring on top and a thrust steel ring at the bottom of the section of metal pipe, which are welded to it with a one-sided weld along the support contour.

[0040] When performing a butt weld of a thin-walled metal pipe and shortened anchor stud bolts, a double-sided weld is provided, the thickness of the weld leg , where q МТ - thickness of steel of a section of pipe metal, mm.

[0041] The lower part of the metal pipe of the column base is equipped with a thrust ring with through holes for passing self-anchoring expansion bolts and fixing the metal pipe to the foundation slab.

[0042] Required metal thickness ( ) permanent formwork is calculated using equation (1)

[0043] , (1)

[0044] where - the required cross-sectional area of ​​the permanent formwork metal is calculated using equation (2)

[0045] , (2)

[0046] where - longitudinal force on the foundation edge, kN;

[0047] And – coefficients of conditions of joint work of concrete and metal;

[0048] And - calculated compressive strength of concrete and metal, MPa; - cross-sectional area of ​​concrete in the pipe, mm 2 , calculated using equation (3)

[0049]

[0050] – the length of the circumference of the pipe at the middle of its thickness, calculated using equation (4):

[0051] , (4)

[0052] where – average diameter of permanent formwork pipe;

[0053] – radius of concrete cross-section in the pipe, mm;

[0054] – an irrational number.

[0055] The outer surface of the pipe metal, shortened anchor stud bolts and self-anchoring spacer bolts for fastening the column base are covered with bitumen insulation.

[0056] Example: Given: Permanent metal formwork - metal pipe

[0057] (R s =350 MPa; t s =0.9); outer diameter d МТ =500 mm; radius of metal pipe r=500 / 2=250 mm; radius of concrete section r в »249 mm; heavy concrete class B 45 (R в = 5 MPa; t в =1.2); preliminary thickness of the pipe metal θ МТ , min =1 mm; average pipe diameter d т=398 mm; length of the pipe circumference by average diameter ; longitudinal force N=6200 kN.

[0058] It is necessary to determine the calculated thickness of the column pipe metal.

[0059] Calculation: 1) Cross-sectional area of ​​concrete filling the pipe ( ) is calculated using equation (3)

[0060] .

[0061] 2) Required cross-sectional area of ​​the pipe metal calculated using equation (2)

[0062]

[0063] 3) The calculated thickness of the metal of the permanent formwork pipe is calculated using equation (1)

[0064] .

[0065] Using permanent column base formwork made in the form of a compressed concrete pipe element leads to a reduction in labor costs, savings and concrete by 30-50% when making a column foundation.

[0066] Increased strength and rigidity of the column base are achieved through the use of permanent formwork in the form of a steel pipe. As a result, the concrete in the column base operates under compression without the possibility of lateral expansion. Lateral expansion of the concrete is limited by a thin-walled steel pipe, which absorbs the secondary tensile forces generated in the concrete under the load transferred from the column. At the same time, the thin-walled pipe absorbs some of the forces from the column. Under these conditions, the structural materials perform most effectively; the strength of the concrete under triaxial compression is increased, and the stability of the thin-walled steel pipe is ensured by the interaction with the concrete in the structure. This, in turn, allows for the use of less material, making it work more efficiently.Reducing the labor intensity, labor costs, and construction time of a reinforced concrete foundation is achieved through a simpler design of permanent formwork and its construction technology. This formwork also serves as an external reinforcement system.

[0067] Sources of information

[0068] 1. Patent RU 2652770, IPC E04 B 2 / 86; Permanent steel fiber concrete formwork / Dorf V.A., Krasnovsky R.O., Krol I.S. and others; declared 17.03.2017, published 28.04.2018, Bulletin No. 13.

[0069] 2. Patent RU 2668669, IPC E04 B 2 / 86; Permanent formwork for monolithic concrete and reinforced concrete made of inorganic glass (variants). / Gresh K.O.; declared 11.01.2018, published 02.10.2018, Bulletin No. 28.

Claims

1. A reinforced concrete column base characterized by the fact that it contains permanent formwork formed by a section of a thin-walled metal pipe, the height of which is equal to the height of the column base, which is filled with structural concrete of increased compressive strength, equipped with stiffening elements welded to it with a one-sided weld along the support contour, provided with a support steel ring in the upper part, and a thrust steel ring in the lower part, anchor stud bolts of the support steel ring, equipped with high nuts and elastic washers, are connected to the inner surface of the section of thin-walled metal pipe by welded seams; the thrust steel ring is provided with through holes for passing self-anchoring spacer bolts and securing the thin-walled metal pipe to the foundation slab, wherein the outer diameter of the support steel ring is equal to the diameter of the thin-walled metal pipe, and the inner diameter is equal to the diameter of the column;the inner diameter of the thrust steel ring is equal to the diameter of the metal pipe, and the outer diameter exceeds the pipe diameter by at least the amount required to accommodate the expansion bolts.

2. A column base according to paragraph 1, characterized in that the calculated resistance of the structural concrete and the pipe metal to compression is taken into account taking into account their joint operation as part of a pipe-concrete column base.

3. A column sub-structure according to paragraph 1, characterized in that the section of metal pipe is adopted with a thickness of 1 to 6 mm, the required thickness of the pipe metal is adopted based on the calculation results, the section of metal pipe is made of electric-welded steel with the calculated resistance .

4. A column base according to paragraph 1, characterized in that the section of metal pipe is limited at the top of the column base by the edge of the foundation, and at the bottom by the foundation slab.

5. A column sub-structure according to paragraphs 1 and 3, characterized in that the butt seam of the thin-walled metal pipe and the fastening of the anchor bolts-studs are made with a double-sided weld, the thickness of the weld leg , whereθ МТ - thickness of steel of a section of pipe metal, mm.

6. A column sub-post according to item 1, characterized in that the required thickness of the metal ( ) permanent formwork is calculated using the equation , Where – the length of the pipe circumference at the middle of its thickness; – the required cross-sectional area of ​​the permanent formwork metal is calculated using the equation , Where – longitudinal force on the foundation edge, kN; And – coefficients of conditions for timely operation of concrete and metal; And – calculated compressive strength of concrete and metal, MPa; – cross-sectional area of ​​concrete in the pipe, mm2 , calculated by the equation , Where – an irrational number; – radius of concrete cross-section in the pipe, mm; – the length of the circumference of the pipe at the middle of its thickness, calculated using the equation , Where – an irrational number; – average diameter of permanent formwork pipe.

7. A column sub-base according to paragraph 1, characterized in that the outer surface of the pipe metal, anchor stud bolts and self-anchoring spacer bolts of the fixed column sub-base are covered with bitumen insulation.

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