RU2308581C2 - Column and column head reinforcing device - Google Patents

Column and column head reinforcing device Download PDF

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Publication number
RU2308581C2
RU2308581C2 RU2005130599/03A RU2005130599A RU2308581C2 RU 2308581 C2 RU2308581 C2 RU 2308581C2 RU 2005130599/03 A RU2005130599/03 A RU 2005130599/03A RU 2005130599 A RU2005130599 A RU 2005130599A RU 2308581 C2 RU2308581 C2 RU 2308581C2
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Prior art keywords
column
supporting
steel
tension
strut
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RU2005130599/03A
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Russian (ru)
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RU2005130599A (en
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Николай Алексеевич Ильин (RU)
Николай Алексеевич Ильин
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Государственное образовательное учреждение высшего профессионального образования "Самарский государственный архитектурно-строительный университет" (СГАСУ)
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Priority to RU2005130599/03A priority Critical patent/RU2308581C2/en
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Abstract

FIELD: construction, particularly to strengthen reinforced concrete columns and column heads damaged by fire or during accident.
SUBSTANCE: reinforcing device comprises thrust members made as bearer pressed to column to be reinforced with normal force and as seat, distance means body, which are formed of one or several pre-stressed branches. Device also has tightening units including eye screws and tightening nuts, which at least partly unload damaged part of column or column head to be reconstructed. Eye screw nuts connected to distance means body, are screwed to bring the device into operation. Then the device is concreted.
EFFECT: increased reliability and safety of column to be reinforced due to efficient reinforcing device members usage.
24 cl, 8 dwg

Description

The invention relates to construction and can be used to strengthen the supporting structures of operated buildings, more specifically when reinforcing heavily damaged reinforced concrete columns and / or their heads in a fire.
Severe thermal damage to the columns and their heads includes peeling of destructive concrete to a depth of 40-80 mm or more, buckling of reinforcing bars, and the appearance of residual thermal tensile stresses (up to 10 kN / cm 2 ) in the working reinforcement of the columns. Damage to the heads is characterized by a greater degree of destruction of concrete in the section of the head than in the section of the column, due to a deeper heating of the head, a significant decrease in the area of abutment at the junction of the crossbar with the column due to spalling of destructive concrete under the end plate and head anchors, as a result of which cracks are possible a slice in concrete from the combined action of the load and fire.
With severe damage to the heads, there is a danger of brittle destruction of the columns and the subsequent collapse of the building crossbars.
In some cases, it is advisable to repair damaged heads without dismantling the crossbars and columns, or unloading them completely or partially.
A device is known for recovering compressed elements (columns) with additional stressed metal profile elements. / see Onufriev N.M. Reinforcement of reinforced concrete structures of industrial buildings and structures. - L. - M .: Stroyizdat, 1965; chap. VIII: Prestressed reinforcement braces. - S.241-247 / [1].
The reasons that impede the achievement of the technical result indicated below when using the known recovery device include the fact that in the known device, prestressed struts increase the bearing capacity of only the columns, therefore, it is impossible to ensure proper reinforcement of the damaged head; with inaccurate manufacture of prestressed struts along their length in a known device, it is impossible to reliably incorporate them into joint work with a reinforced column, therefore, the accuracy of controlling the degree of unloading of the junction of the crossbar and the column head is reduced; the cross-section of the strut branches is taken constructively, with a large overspending of the metal for reinforcement, therefore, in the manufacture of the known device, the metal consumption and the complexity are increased; in the known device, when using metal without structural fire protection, the actual fire resistance of the reinforcing elements, in particular the column as a whole, is reduced.
A device is known for reinforcing columns, including a prestressed metal clip, in the upper part of which a tensioning unit is fixed, a clip of 4 rolling corners connected in pairs by connecting strips in two branches, which are longitudinally crimped by a spacer device. / see A.S. SU No. 607932, class 2 E04G 23/02. The way to strengthen the columns. / V.V.Guselnikov. Publ. 05/25/78. Bull. No. 19 / [2].
For reasons that impede the achievement of the technical result indicated below when using the known device for amplifying the column and its head, the known device uses a bulky, metal-intensive clip from rolling corners; the efficiency of the known amplification device is reduced due to the fact that the load screw of the tension unit has a hinge at both ends, while the coefficient of its reduced length is very significant; the supporting platform for the crossbar is significantly removed from the strut branch, therefore, a bending moment additionally arises, acting on this strut branch and the supporting table, the overall dimensions of the head section of the reinforced column are increased; in the known device when using metal without structural fire protection, the actual fire resistance of the reinforcing elements in particular and the column as a whole is reduced.
The closest technical solution to the invention in terms of features is a device comprising a metal cage made of corners mounted along the sides of the column, equipped with tensioning nodes, each of which consists of supporting elements and a tensioning screw, while the metal casing is made integral in height, and supporting elements are fixed at the abutting ends of the components of the casing / see A.S. SU No. 916722, class 3 E04G 23/02. A device for strengthening columns. / M.D. Boyko. Publ. 04/05/82. Bull. No. 12 / [3]; - taken as a prototype.
For reasons that impede the achievement of the technical result indicated below, when using the known device for strengthening columns and their heads, adopted as a prototype, is that in the known device for its manufacture consumes a significant mass of metal, ineffectively used to strengthen columns and its heads, support nodes of the known device at the bottom and at the top of the column do not have rigid fastening, the components of the branches of the cage are connected by a tension screw characterizing their articulated abutment, in a known manner For the arrangement, the location of the tensioning screws not at the center of gravity of the cross-section of the corner of the holder leads to a bending moment from the spacer force acting on the tensioned branches of the components of the holder; when using metal for a known amplification device without constructive fire protection, the actual fire resistance of the amplification elements and columns is reduced.
The invention consists in the following. The problem to which the claimed invention is directed, is to increase the reliability and safety of the state of reinforced columns and their heads, which received heavy local damage, to reduce steel consumption and material costs due to the rational use of elements of the amplification device.
EFFECT: rational and effective reinforcement of a damaged column and its head, reliable inclusion in the joint work of a prestressed strut with control of prestresses, a reinforced column and its head, rigid connection of a cargo screw with a bearing branch of the strut, halving the coefficient of the reduced length of the screw when calculating strength and its stability as a compressed element, simplification of the transmission design “cargo screw - thrust nut" of the proposed tension unit in the design and manufacture of it , increase of reliability in work, obtaining a big gain in strength, ensuring silent, slow and smooth movements with great accuracy, placing cargo screws in the center of gravity of the cross-sections of the corners of the struts, improving the work of the tensioned branches of the struts during compression, increasing the degree of control of the unloading of the reinforced column and its the head with strained struts, reducing the metal consumption for the manufacture of the amplification device and obtaining the possibility of efficient use of the metal when reinforcing the column and its head providing fire protection of metal elements of the amplification device.
The specified technical result during the implementation of the invention is achieved by the fact that in the known device for strengthening the columns and their heads, including thrust elements, tension struts and tension units, the thrust element of the reinforced column is made in the form of a support table from below and a stop shoe on top of the tension strut, the support table is made from a steel profile, equipped with patch rods for attaching it to the working reinforcement of the column, reinforced with stiffeners, equipped with holes or grooves for installing cargo screws of the tensioned strut and coupling clamps provided with studs with tension nuts, the frame of the tensioned strut is made of one or several branches connected by supporting plates at the ends and clamps-straps along their length, tension nodes installed between the lower supporting plate of the strut and the top of the supporting table, includes cargo screws with tension nuts, metal elements of the amplification device have a fireproof coating.
In addition, the features of the device are that the support table is installed at any given height of the reinforced column.
When reinforcing a loaded column damaged on one side (face), the support table and the tension strut are installed on the same side (face).
When reinforcing a loaded column damaged from two opposite or four sides, supporting tables and tension struts are installed on two opposite sides (sides).
The supporting table is made of a section of a bent steel corner or rolled corner steel.
The supporting table is made of a piece of steel bent or hot-rolled channel.
The supporting table is made of metal plates welded together and forming an angle or channel-shaped cross section.
The dimensions of the cross sections of the elements of the supporting table, reinforced with stiffeners, are taken according to the results of checking the stability of the racks and waist sheets of bent and compressed elements.
The diameters of the tie clamps-pins of the supporting table and their number are taken according to the calculation of the strength of the bolted joints in bending when constraining the rotation of the fastening element.
The bearing branches of the strut are made of pieces of bent steel corner or rolled angle steel.
The bearing branches of the spacer are made of a steel pipe of rectangular or circular cross-section.
The supporting branches of the spacer are made of pieces of hot-rolled reinforcing bar steel ⌀ 10-80 mm.
The diameter of the cargo screws and their number are determined by strength and stability, depending on the magnitude of the unloading force of the column.
Each cargo screw is placed in the center of gravity of the cross section of the bearing branch and is rigidly attached to the spacer.
The spacer shoe is made of a piece of steel bent or hot-rolled channel.
The spacer shoe is made of steel plates with a thickness of at least 6 mm, welded together in the form of a thrust box or channel.
Shoe surfaces that are jointed with the support of the crossbar and subjected to firing by burners are recessed “into the juice” of a plastic cement-sand mortar with a composition of 1: 3 with squeezing.
Overhead shorty rods for attaching the supporting table to the working reinforcement of the column are made of pieces of hot-rolled reinforcement or round steel with a diameter of 10-40 mm.
The height of the weld connecting the elements of the reinforcement device is accepted as calculated for shear and bending, but not less than 6 mm.
After the prestressing strut has been put into operation, the lower strut support plate and the top of the support table are connected by a metal plate or a corner piece.
In the additionally laid concrete of the column head, indirect reinforcement is installed in the form of nets or separate U-shaped crossed steel brackets with a given section of 25-50% of the cross-sectional area of the longitudinal reinforcement of the column.
To prevent the tension nuts from loosening under load, they were locked relative to the tie rods and cargo screws by plastic deformation, welding or elastic washers.
The metal elements of the spacer device are subjected to firing by burners and are coated with a layer of concrete, the thickness of which is adopted depending on the required fire resistance of the column on the basis of loss of bearing capacity.
The class of additionally laid concrete in compressive strength is accepted on ordinary Portland cement or expanding cement equal to the concrete class of the reinforced column, but not less than B 15.
The drawings show:
figure 1 shows the skeleton of the spacer with cargo screws from below and shoes from above;
figure 2 is a side view of figure 1:
figure 3 is a top view of figure 1;
1 - reinforced column with a head; 2 - channel-shaped shoe; 3 - stiffener plate under the shoe; 4 - branches (racks) of the spacer frame; 5 - straps-clamps of the spacer frame; 6 - thrust plate of the spacer frame; 7 - cargo screws; 8 - persistent nuts high;
figure 4 shows the supporting table;
figure 5 is a top view of figure 4;
figure 6 is a side view of figure 4:
9 - skeleton of the supporting table; 10 - longitudinal reinforcement of the column; 11 - pads shorty; 12 - stiffness plates of the supporting table; 13 - stiffeners; 14 - coupling clamps hairpins;
Fig.7 shows a tension unit (screw strut);
Fig.8 is a side view of Fig.7:
7 - cargo screws; 8 - persistent nuts high; 15 - elastic washers or locknuts; 16 - a connecting level - a piece of a corner; 17 - welded joint; 18 - fire retardant coating of metal elements of the amplification device.
Information confirming the possibility of carrying out the invention with obtaining the above technical result.
An example of a specific implementation. The reinforcement device for the extreme column 1 of a one-story industrial building with a height of H = 7.2 m (heavy thermal damage in a section 1.5 m long from the head on three faces of the column with a section B × C = 400 × 400 mm) contains a stop shoe 2, a spacer frame 4, a tension unit with cargo screws 7 and a support table 9.
The persistent shoe 2 for the rafter reinforced concrete truss is made of a section of channel No. 24 with a length of 180 mm; a plate 3 of sheet steel 30 mm thick is additionally installed under the shoe to increase its rigidity.
The spacer frame contains a stiffening plate 3 under the thrust shoe, two spacer branches 4 of hot-rolled equal-angle steel corners 2∟75 × 75 × 8 mm, 1930 mm long, clamp straps 5 of steel plates with a cross-section of 6 × 60 mm, clamp pitch 300 mm, thrust plate 6 made of sheet steel with a thickness of 50 mm.
The supporting table contains: a skeleton 9 from a section of steel hot-rolled channel No. 24 (length 460 mm, channel height 240 mm, shelf width 90 mm, wall thickness 5.6 mm, shelf thickness 10 mm), an additional plate 15 to increase the rigidity of the channel shelf, two short pads 11 (pieces of hot-rolled bar reinforcement of class A 400, diameter 22 mm) connected by a seam 18 to longitudinal reinforcement 2 ⌀ 22 A 400 (A-III), steel stiffeners 13 with a thickness of 10 mm, two tie clamps-studs 14 with a diameter of 24 mm, a tension node from a persistent plate 6 (sheet steel 50 mm thick), stiffening plates 12 (steel 30 mm thick), two cargo screws 7 with high tension nuts 8 (screw length 260 mm, thread diameter 36 mm, thread length 36 mm, thread type - metric).
Introduction to the work of the parts of the device amplification of the column and its head made as follows.
The branches of the skeleton of the strut 4, channel-shaped shoe 2, cargo screws 7 and the skeleton of the supporting table 9 are made in a mechanical workshop.
The supporting table to the surface of the column 1 is strengthened with clamps 14 with an interference fit, a tensioned strut 4 is installed on the skeleton of the supporting table 9 with a channel-shaped shoe 2, supporting the support unit of the truss truss, by tightening the thrust nuts 8 of the cargo screws 7 with a predetermined (controlled) force - the upper one is unloaded part of column 1 and its head.
After introducing the branches of the skeleton of the strut 4 into operation, the thrust plate of the strut 6 and the top of the skeleton of the supporting table 9 are connected by a connecting strip (corner piece) 16 using a welded joint 17.
To prevent weakening of the persistent high nuts 8 under load, they were locked relative to the coupling clamps-studs 14 and cargo screws 7 by plastic deformation, welding or elastic washers 15.
The metal elements of the reinforcement device have a fire-retardant coating 18 - the layer of heavy concrete in compression strength is taken equal to the concrete class of the reinforced column, but not less than B 15.
Using the proposed device reinforcing columns and their heads eliminate severe damage without dismantling or preliminary unloading of the supporting structure, making the most of the residual strength of the materials during its further operation.
The proposed device allows you to rationally and effectively reinforce a heavily damaged column and its head due to the reliable inclusion in the joint work of a tensioned strut with control of prestresses.
A rigid connection of the cargo screw with the supporting branch of the spacer halves the coefficient of the reduced length of the screw when calculating the strength and stability of it as a compressed element.
The proposed device simplifies the design of the transmission "cargo screw - thrust nut" of the proposed tension unit in the design and manufacture of it, increasing the reliability, gain in strength and providing silent, slow and smooth movement of the tensioned struts with great accuracy.
Placing cargo screws in the center of gravity of the cross-sections of the corners of the struts improves the work of the tensioned branches of the struts during compression.
The proposed device allows to increase the degree of control of the unloading of the reinforced column and its head with tension struts, to reduce by 2-3 times the consumption of metal for its manufacture and to provide the required fire protection of the metal elements of the amplification device.
The proposed device is used in industry when reinforcing an extreme reinforced concrete column and its head.
The column with severe thermal damage to the upper part was located at the border between the partially operational and emergency state.
The height of the columns is 7.2 m, the cross section is 400 × 400 mm, reinforced in the upper part 4 ⌀ 22 A 400 (A-III), while two longitudinal rods 2 ⌀ 22 A 400 were freed from the destructive layer of concrete during technical inspection and the cross section of the head did not participate in the work.
Heavy column concrete with limestone aggregate of class B 25 (concrete grade according to the M-300 project).
The material of the elements of the amplification device is steel grade Art. 3 cl. 2-1. The design load on the column is 684 kN (68.4 tf).
Work on strengthening the column and its head was carried out without stopping the main production in the building (Samara, 2005).
Information sources
1. Onufriev N.M. Reinforcement of reinforced concrete structures of industrial buildings and structures. - L. - M .: Stroyizdat, 1965; ch. VIII: Prestressed reinforcement struts. - S. 241-247.
2. A.S. SU No. 607932, class 2 E04G 23/02. The way to strengthen the columns. / V.V.Guselnikov. Publ. 05/25/78. Bull. No. 19.
3. A.S. SU No. 916 722, class 3 E04G 23/02. A device for strengthening columns. / M.D. Boyko. Publ. 04/05/82. Bull. No. 12.

Claims (24)

1. A device for reinforcing columns and their heads, including thrust elements, tension struts and tension units, characterized in that the thrust element of the reinforced column is made in the form of a support table from below and a stop shoe on top of the tension strut, the support table is made of steel profile, equipped with invoices rods for attaching it to the working reinforcement of the column, reinforced with stiffening ribs, equipped with holes or grooves for installing load screws of the tension strut and coupling clamps equipped with studs with with open nuts, the skeleton of the tensioned strut is made of one or several branches connected by support plates at the ends and clamps-straps along their length, tension nodes installed between the lower support plate of the strut and the top of the support table include cargo screws with tension nuts, metal elements of the amplification device have a fire retardant coating.
2. The device according to claim 1, characterized in that the supporting table is installed at any given height of the reinforced column.
3. The device according to claim 1, characterized in that when reinforcing a loaded column damaged on one side, the support table and the tension strut are installed on the same side.
4. The device according to claim 1, characterized in that when reinforcing a loaded column damaged from two opposite or four sides, support tables and tension struts are installed from two opposite sides.
5. The device according to claim 1, characterized in that the supporting table is made of a section of a bent steel corner or rolled corner steel.
6. The device according to claim 1, characterized in that the supporting table is made of a piece of steel bent or hot-rolled channel.
7. The device according to claim 1, characterized in that the supporting table is made of metal plates welded together and forming an angle or channel-shaped cross section.
8. The device according to claim 1, characterized in that the dimensions of the cross sections of the elements of the supporting table reinforced with stiffeners are taken according to the results of checking the stability of the struts and waist sheets of bent and compressed elements.
9. The device according to claim 1, characterized in that the diameters of the tie clamps-pins of the supporting table and their number are taken to calculate the strength of the bolted joints in bending when constraining the rotation of the fastening element.
10. The device according to claim 1, characterized in that the supporting branches of the spacer are made of segments of a bent steel corner or rolled angle steel.
11. The device according to claim 1, characterized in that the supporting branches of the spacer are made of a steel pipe of rectangular or circular cross section.
12. The device according to claim 1, characterized in that the supporting branches of the spacer are made of pieces of hot-rolled reinforcing steel bars ⌀ 10-80 mm.
13. The device according to claim 1, characterized in that the diameter of the cargo screws and their number are determined based on strength and stability, depending on the magnitude of the unloading force of the column.
14. The device according to claim 1, characterized in that each cargo screw is placed in the center of gravity of the cross section of the bearing branch and is rigidly attached to the spacer.
15. The device according to claim 1, characterized in that the spacer shoe is made of a piece of steel bent or hot-rolled channel.
16. The device according to claim 1, characterized in that the spacer shoe is made of steel plates with a thickness of at least 6 mm, welded together in the form of a thrust box or channel.
17. The device according to claim 1, characterized in that the shoe surfaces mating with the support of the crossbar subjected to firing by burners are recessed “into the juice” of a 1: 3 cement-sand plastic mortar with squeezing.
18. The device according to claim 1, characterized in that the overhead shorty rods for attaching the supporting table to the working reinforcement of the column are made of pieces of hot-rolled reinforcement or round steel with a diameter of 10-40 mm
19. The device according to claim 1, characterized in that the height of the weld connecting the elements of the reinforcement device is adopted for shear and bending, but not less than 6 mm
20. The device according to claim 1, characterized in that after the introduction of the prestressed strut into operation, the lower base plate of the strut and the top of the supporting table are connected by a metal plate or a piece of corner.
21. The device according to claim 1, characterized in that in the additionally laid concrete of the column head, indirect reinforcement is installed in the form of nets or separate U-shaped crossed steel brackets with a given section of 25-50% of the cross-sectional area of the longitudinal reinforcement of the column.
22. The device according to claim 1, characterized in that in order to prevent the tension nuts from loosening under load, they are locked against plastic tie rods and cargo screws by plastic deformation, welding or elastic washers.
23. The device according to claim 1, characterized in that the metal elements of the spacer device are subjected to firing by burners and covered with a layer of concrete, the thickness of which is adopted depending on the required fire resistance of the column on the basis of loss of bearing capacity.
24. The device according to claim 1, characterized in that the class of additionally laid concrete in terms of compressive strength is adopted on ordinary Portland cement or expanding cement equal to the concrete class of the reinforced column, but not less than B 15.
RU2005130599/03A 2005-10-03 2005-10-03 Column and column head reinforcing device RU2308581C2 (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2442867C1 (en) * 2010-08-16 2012-02-20 Федеральное Государственное Автономное Образовательное Учреждение Высшего Профессионального Образования "Сибирский Федеральный Университет" Device for reinforcing bearing frame
RU2498035C1 (en) * 2012-05-11 2013-11-10 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Самарский государственный архитектурно-строительный университет" (СГАСУ) Spacer for building column reinforcement
RU2498033C1 (en) * 2012-03-13 2013-11-10 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Самарский государственный архитектурно-строительный университет" (СГАСУ) Device to reinforce column and joined elements of building slab
RU2507356C2 (en) * 2012-05-11 2014-02-20 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Самарский государственный архитектурно-строительный университет" (СГАСУ) Method to manufacture spacers for reinforcement of building column

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2442867C1 (en) * 2010-08-16 2012-02-20 Федеральное Государственное Автономное Образовательное Учреждение Высшего Профессионального Образования "Сибирский Федеральный Университет" Device for reinforcing bearing frame
RU2498033C1 (en) * 2012-03-13 2013-11-10 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Самарский государственный архитектурно-строительный университет" (СГАСУ) Device to reinforce column and joined elements of building slab
RU2498035C1 (en) * 2012-05-11 2013-11-10 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Самарский государственный архитектурно-строительный университет" (СГАСУ) Spacer for building column reinforcement
RU2507356C2 (en) * 2012-05-11 2014-02-20 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Самарский государственный архитектурно-строительный университет" (СГАСУ) Method to manufacture spacers for reinforcement of building column

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Effective date: 20071004