RU2517292C1 - Fireproof double-tee pillar of building - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: steel pillar double tee is equipped with fastening nuts and setting screws with hidden heads and screwed-in sharpened end. The elements of the sheet lining are fixed tightly to the shelves of the pillar double tee, elements of the tile lining - tightly to the double tee wall. Thickness of elements of fireproof lining is pre-determined with account of thermal properties of its materials, conditions of pillar double tee heating during fire and normative limit of building pillar fire resistance.

EFFECT: increased reliability of fixation of elements of large-size lining, increased limit of steel pillar fire resistance, reduced risk of pillar collapse in initial stage of fire.

13 cl, 2 dwg

Description

The invention relates to the field of fire safety of buildings and structures; hereinafter referred to as buildings. In particular, it can be used in the design and manufacture of structural fire protection of the steel supporting rod of the column, made in the form of a column I-beam, using large-sized sheet, plate and roll cladding.

Unprotected steel structures of a building when exposed to fire in a fire quickly (after 15 ÷ 18 min) lose their bearing capacity, collapse themselves and contribute to the collapse of other structures of the building, which leads to significant material losses.

A known construction of a fire-resistant I-beam column of a building containing a steel I-beam and fire-retardant lining in the form of reinforced concrete slabs of cellular concrete, hollow-core gypsum slabs or plates, vermiculite slabs and asbestos-cement sheets / Bartellemy B., Krüppa J. Fire resistance of building structures / per. with french - M.: Stroyizdat, 1985, - 216 p. (Ch. 4; Sec. 4.2 Materials and methods of protection, Fig. 4.2; 4.4 ÷ 4.6; p. 94 ÷ 98) / [1].

The reasons that impede the achievement of the technical result indicated below when using the known construction of a fireproof I-beam column of a building include the fact that a significant number of carcass elements are used in the known construction and, as a result, the consumption of fire-retardant material and metal for the manufacture of a carcass for fire-retardant lining is increased; when designing voids and gaps between the wall and the flanges of the I-beam and the plates of the protective lining, the cross-sectional dimensions of the lined column increase (the cross-sectional area increases by 75 ÷ 85%); the design limit of fire resistance of the fireproof column is reduced by 25 ÷ 30%; reliability of fastening of elements of large-sized sheet and plate cladding is reduced; the corrosion resistance of the steel supporting rod and the maintainability of the fireproof lining are reduced (if it is possible to obtain mechanical damage and through spalls).

A known design of a fire-resistant I-beam of a building, containing a steel I-beam and fire-retardant cladding from large-sized sheets and plates mounted on a rel — the gap between the fire-retardant cladding and the faces of the protected steel supporting rod is adopted at least 25 mm; the fireproof cladding frame is made in the form of a frame consisting of steel longitudinal and transverse elements with a height of 40 ÷ 75 mm; the steel elements of the frame were fastened to each other by self-tapping screws 5 × 25 ÷ 5 × 45 / Romanenkov I.G., Levites F.A. Fire protection of building structures. - M .: Stroyizdat, 1991 .-- 320 p. (Chapter 4 Structural fire protection methods; Sec. 4.2 - Large-sized sheet, plate and roll cladding; Fig. 8, p.131-133) / [2].

The reasons that impede the achievement of the technical result indicated below when using the known construction of a fireproof column of a building include the fact that a significant number of carcass elements are used in the known construction and, as a result, the metal consumption for the manufacture of a carcass for fireproof cladding is increased; when designing voids and gaps between the wall and the flanges of the I-beam and the plates of the protective lining, the cross-sectional dimensions of the lined column increase (the cross-sectional area increases by 80 ÷ 95%; the consumption of lining materials - by 45 ÷ 50%); the design limit of fire resistance of the fireproof column is reduced by 25 ÷ 30%; reliability of fastening of elements of large-sized sheet and plate cladding is reduced; the corrosion resistance of the steel supporting rod and the maintainability of the fireproof lining are reduced (if it is possible to obtain mechanical damage and through spalls).

A known construction of a fire-protected I-beam of a building, containing a steel supporting rod with anchors on its lateral sides, a frame made of C-shaped profiles, consisting of longitudinal elements with bends along the edges of the shelves and transverse elements, a cladding made of sheet materials, which is attached at 40 ÷ 50 mm to form a gap between the shelves I beam (area of empty space between the flanges and the wall I-beam №20 and facing elements in cross-section flame retardancy column is _empty a = 650 cm ²⁾ / .s.SU 887,755 MKI-3 E 04 B 1/94 Construction of the building assembly / JV Pokrovsky, V.V. Fedorov, M.M. Karbachinsky and others; application 02.21.80; publ. 12/12/81; Bull. No. 45 / [3].

The reasons that impede the achievement of the technical result indicated below when using the known construction of a fireproof I-beam column of a building include the fact that a significant number of carcass elements are used in the known construction and, as a result, the metal consumption for the manufacture of a carcass for fireproof cladding is increased; when designing voids and gaps between the wall and the flanges of the I-beam and the plates of the protective lining, the cross-sectional dimensions of the lined column increase (the cross-sectional area increases by 60 ÷ 70%; the consumption of lining materials - by 40 ÷ 45%); the design limit of fire resistance of the fireproof column is reduced by 25 ÷ 30%; reliability of fastening of elements of large-sized sheet and plate cladding is reduced; the corrosion resistance of the steel supporting rod and the maintainability of the fireproof lining are reduced (if it is possible to obtain mechanical damage and through spalls).

The closest technical solution to the invention in terms of all the features is the design of a fireproof I-beam column of a building, comprising a supporting rod, frame elements and sheet cladding attached to the frame on the relate; frame elements are made of steel profiles with bends, and the bearing rod is equipped with anchors, providing a gap of 60 ÷ 80 mm between the bearing rod and the lining. The cladding elements made of sheet material are fixed to the frame elements with self-tapping screws / А.с. SU No. 773 218 MKI-3 E04B 1/94 Building element / Yu.V. Pokrovsky, V.V. Fedorov et al .; declared 04/13/79; publ. 10.23.80, Bull. No. 39 / [4] taken as a prototype.

For reasons that impede the achievement of the technical result indicated below when using the known construction of a fireproof I-beam column of a building adopted as a prototype, the known construction uses a significant number of carcass elements and, as a result, increased metal consumption for the manufacture of a carcass for fireproof cladding; when designing voids and gaps between the wall and the flanges of the I-beam and the plates of the protective lining, the cross-sectional dimensions of the lined column increase (the cross-sectional area increases by 75 ÷ 85%); the design limit of fire resistance of the fireproof column is reduced by 25 ÷ 30%; reliability of fastening of elements of large-sized sheet and plate cladding is reduced; the corrosion resistance of the steel supporting rod and the maintainability of the fire retardant lining are reduced (if it is possible to obtain mechanical damage and through spalls); it is not justified to determine the thickness of the elements of sheet fire-retardant cladding of the steel supporting rod of the column, depending on the degree of fire resistance of the building and the thermophysical properties of the cladding materials.

The invention consists in the following. The problem to which the claimed invention is directed, is to increase the fire resistance and operational reliability of the fireproof I-beam columns of the building, as well as to improve the fire-technical and economic indicators of steel structures of buildings.

EFFECT: increased reliability of fastening of elements of a large-sized sheet and plate fire-retardant lining of an I-beam column and frame elements for it; reduction in the number of frame elements for fire retardant cladding; weight reduction of metal and facing materials; simplification of the manufacture of fire-retardant cladding frame elements; a decrease in the cross-sectional area of the fire-protected double tee column by 75 ÷ 95%; increasing the fire resistance of a steel column with a supporting rod in the form of a column I-beam by 25 ÷ 30%; increased safety during fire fighting and rescue and recovery operations; reduction of possible fire losses; improving the reliability of the fireproof columns during normal operation of the building and in a fire; simplification of installation of frame elements and fire retardant cladding; increasing the rigidity of the connection of the columnar I-beams with sheets and plates of the cladding and the resistance of the fire retardant cladding to mechanical stress; increasing the efficiency of fire protection of a steel supporting rod with a large-sized cladding; increasing the corrosion resistance of the steel column I-beam and the maintainability of fire retardant cladding in the event of local mechanical damage; reducing the complexity of mounting frame elements and fire retardant cladding elements; reduction in welding and wet construction processes; substantiation by the engineering calculation of the thickness of the elements of the sheet and plate fire-retardant cladding of a steel column I-beam depending on the degree of fire resistance of the building, the thermal diffusion of the cladding materials and the heating conditions of the shelves and walls of the I-beam in case of fire.

The specified technical result when using the invention is achieved by the fact that in the known construction of the fireproof I-beam of the building containing the supporting rod and sheet cladding, the feature is that the supporting rod is made in the form of a steel column I-beam and each end of the steel supporting rod is equipped with fixing nuts and set screws with countersunk heads and screwed-in pointed ends and straight slot; installation screws are attached to the shelves of the columnar I-beam contact, close to the elements of sheet fire retardant cladding, to the wall of the I-beam are attached contact, close to the elements of the plate fire retardant cladding; the thickness of the cladding elements is determined taking into account the thermal diffusion of its materials, heating conditions and the degree of fire resistance of the building.

Other features is that an anti-corrosion layer is applied to the surface of the steel supporting rod; fire retardant cladding elements are made of refractory plasterboard sheets; the elements of the plate fire-retardant cladding are made in the form of piercing mats of mineral wool; fireproof cladding cladding elements are made in the form of Rockwool mineral wool slab products; the length of the screwed end of the set screw into the elements of the fire-retardant plate cladding is adopted not less than l _min ≥0.2 · h, here h is the height of the steel column I-beam; a layer of fiberglass is applied to the outer surfaces of the fireproof lining elements; plaster is applied to the outer surfaces of the fireproof lining elements; the thickness of the elements of the fire retardant lining δ _o.mp , mm, is determined by the exponential equation (1):

$${\delta }_{\mathrm{about}.mp}=0.7\cdot C\cdot D_{ar}^{0.8}/m_o,(\mathrm{one})$$

where C is the degree of fire protection of the steel column I-beam, cm;

D _ar is an indicator of thermal diffusion of the cladding material, mm ² / min;

m _o - an indicator of the heating conditions of the column I-beam (0.5 ÷ 1).

The value of the fire protection limit of a separate layer of fire-retardant cladding τ _{u, co} , min, calculated by the exponential equation (2):

$${\tau }_{u,co}=65\cdot m_{o\mathrm{one}}\cdot {\left({\delta }_{co}/D_{co}\right)}^{1.41},(2)$$

where m _o1 is an indicator of the heating conditions of the cladding layer, (0.5 ÷ 1);

δ _co - the thickness of a single layer of fire retardant cladding, mm;

D _co - an indicator of thermal diffusion of the cladding material, mm ² / min.

The indicator of the heating conditions of the coronal I-beam flange is calculated by the power equation (3):

$$m_0={0.7}^{\delta x/\delta y}\text{A.},(3)$$

where δ _x and δ _y are the thickness of the fire protection of the flange of the column I-beam along the axes X and Y, mm.

The ends of the shelves of the columned I-beam are protected from fire by an asbestos cord. An adhesive layer is applied on the surface of the walls and shelves of the columnar I-beams for additional fastening of the lining.

The causal relationship between the totality of the features and the technical result of the invention is as follows: the use of the proposed design of a fire-resistant I-beam column of the building provides simplicity and reliability of fastening the elements of the large-sized cladding and frame elements for it through the use of set screws with countersunk head with a long screwed pointed end and a hard connection (welding) of the fixing nut to the shelves of the column I-beam; a reduction in the mass of metal for the manufacture of carcass elements of the fire-retardant cladding is performed by reducing the number of carcass elements; a 75–95% reduction in the cross-sectional area of the fireproof I-beam column due to the lack of void space between the steel supporting rod and the lining; increasing the fire resistance of a steel column with a supporting rod in the form of a column I-beam by 25 ÷ 35% due to the filling of the void space inside the cross section of the column; increasing safety during extinguishing during emergency rescue and restoration operations, as well as reducing losses from fire due to increased fire resistance limits of the building's supporting structures; improving the reliability of the fire-protected columns during normal operation of the building and in fire conditions is possible due to increased rigidity in the contact connection of the column I-beams with sheets and cladding plates, as well as designing the thickness of the cladding elements according to the proposed calculation method depending on the degree of fire resistance of the building, thermal diffusion of cladding materials and heating conditions in case of fire.

Figure 1 shows a cross-section of a fire-resistant I-beam with contact attachment of sheet and plate cladding elements to a steel supporting rod, where the following notation is adopted: 1 - column I-beam; 2 - anti-corrosion layer; 3 - sheet fireproof lining; 4 - plate fireproof lining; 5 - set screws (with countersunk head with a screwed-in pointed end and a straight slot); 6 - fixing nut (for the set screw); 7 - countersunk head of the set screw; 8 - asbestos cord; 9 - fiberglass (plaster); 10 - adhesive layer (mortar); (b and h are the width of the shelf and the height of the I-beam; B and H are the width and height of the cross-section of the fireproof column; d and δ _s are the wall and shelf thickness of the I-beam; δ _x and δ _y are the thickness of the fire protection of the I-beam along the X and Y axes).

In Fig.2 shows a cross section of a fireproof column with a steel supporting rod in the form of a column I-beam No. 20 K-2 (legend 1--10 are shown in Fig. 1; here δ _GKLO and δ _Roc are the thickness of the sheet and plate fire-retardant lining, respectively) ; for example, calculation.

Information confirming the possibility of applying the invention to obtain the above technical result.

During the reconstruction of the university’s academic building, the project provides for fireproof steel columns from a rolling profile. Characteristics of the building and its supporting columns: functional fire hazard class - F 4.2; degree of fire resistance - I (first); class of constructive fire hazard - СО (not fire hazardous); number of floors - 6; standard limit of fire resistance of the supporting column F _{u, n} = 120 min (Table 21, Federal Law of the Russian Federation No. 123-2009); steel supporting rod - column I-beam No. 20K-2, the height of the I-beam h = 198 mm; shelf width b = 200 mm, wall thickness d = 7 mm; shelf thickness δ _s = 11.5 mm; the cross-sectional area of the I-beam A = 53 cm ² .

Fire protection of the I-beam shelves - sheet fireproof lining - fireproof gypsum plasterboard (GKLO) with a thickness of δ ₁ = 12.5 mm; fire protection of the I-wall - plate fire-retardant lining - mats from rockwool M-50 mineral wool.

The indicator of the heating conditions of the column of an I-beam is calculated by the power equation (3):

$$m_0={0.7}^{\delta x/\delta y},(3)$$

where δ _x and δ _y are the thickness of the fire protection of the shelf of the column I-beam along the axes X and Y.

The degree of fire protection of the columned I-beam was calculated by the logarithmic equation (4):

$$C=In\left({\tau }_{uo}/48\cdot {\left(\mathrm{one}-J_{\sigma s}\right)}^3\right),(\mathrm{four})$$

when the intensity of power stresses J _σs = 0.5,

$$C=In\left(0.2\cdot {\tau }_{uo}\right),(5)$$

where C is the degree of fire protection of the column I-beam, cm;

τ _uo - fire protection limit of cladding elements, min;

In is the natural logarithm. The fire protection limit of the cladding is calculated by the algebraic formula (6):

$${\tau }_{uo}=F_{u,n}-{\tau }_{us},(6)$$

where F _{u, n} is the standard limit of fire resistance of the supporting column, min;

τ _us - fire resistance of the column I-beam without fire protection, min.

Example: Given: Steel supporting rod - column I-beam from a rolling profile No. 20 K-2; standard limit of fire resistance of bearing columns for a building of I (first) degree of fire resistance F _{u, n} = 120 min (Table 21 of the Federal Law No. 123-2009); fire resistance of a column I-beam without fire protection τ _us = 20 min; fire retardant lining of columns of a double tee - fireproof drywall sheets (GKLO), thermal diffusion index - D _GKLO = 20 mm ² / min; an indicator of the heating conditions of the I-beam shelves m ₀ = 0.75; δ _x = 30 mm; lining of a wall of an I-beam - mineral wool mats M-50 of the Rockwool product; thermal diffusion index - D _Roc = 68.8 mm ² / min; an indicator of the heating conditions of the I-wall m ₀₂ = 0.5.

Determine the thickness of the elements of sheet and plate cladding.

Decision. 1) The limit of fire protection, cladding is calculated by the algebraic formula (5):

τ _uo = F _{u, mp} -τ _us = 120-20 = 100 min.

2) The degree of fire protection of the columned I-beam with a complex cladding (with J _σs = 0.5) was calculated by the logarithmic equation (4):

C = In (0.2 · τ _uo ) = In (0.2 · 100) = In20 = 3.

3) The required thickness of the sheet of fire-retardant cladding for the shelves of the columnar I-beam with refractory plasterboard sheets (with m ₀₁ = 0.75), calculated by the exponential equation (1):

$${\delta }_{mp,G\mathrm{TO}L\mathrm{ABOUT}}=0.7\cdot C\cdot D_{G\mathrm{TO}L\mathrm{ABOUT}}^{0.8}/m_{01}=0.7\cdot 3\cdot {\mathrm{twenty}}^{0.8}/0.75-31mm.$$

4) The number of layers of lining of the shelves of the columnar I-beam from refractory plasterboard sheets with a thickness of δ ₁ = 12.5 mm each sheet:

n _GKLO = δ _{mp, GKLO} / δ ₁ = 31 / 12.5 = 2.5; accepted n _GKLO = 3 sheets, δ _y = 40 mm;

5) The required thickness of the plate fire-retardant cladding for the wall of the columnar I-beam with Rockwool mineral wool products in the form of M-50 mats (with two-sided heat supply in a fire m ₀₂ = 0.5) is determined by the exponential equation (1):

; $${\delta }_{mp,Roc}=0.7\cdot C\cdot D_{Roc}^{0.8}/m_{0.2}=0.7\cdot 3\cdot {68.8}^{0.8}/0.5=120mm>b/2=200/2=\mathrm{one\; hundred}mm$$

;

accepted δ _Roc = 126 mm.

The structure of the fireproof steel column includes: preparing the surface of the steel column I-beam - 1 and applying an anti-corrosion layer - 2; selection of materials for fire retardant cladding; calculation of the thickness of the cladding elements; manufacturing elements of sheet fire retardant cladding - 3 and plate fire retardant cladding - 4; installation of fixing nuts - 6 on the ends of the shelves of the column I-beam - 1 with a step of 500 ÷ 100 mm along the length (height) of the column; assembly of elements of sheet fire-retardant cladding - 3 and fixing them with set screws - 5 on the shelves of a column I-beam - 1; applying an adhesive layer - 10 on the surface of the wall and shelves of the columnar I-beam - 1 and gluing to them the elements of the plate fire-retardant lining - 4; screwing in each set screw - 5 with countersunk head - 7 and with a pointed end into the elements of the fire retardant cladding - 4 to a depth of l _K ≥0.2 · h (here h is the height of the column I-beam - 1); installation in the grooves (at the locations of the fixing nuts) of an asbestos cord - 8; covering the surface of the elements of the fire-retardant plate cladding - 4 with fiberglass - 9 (if necessary).

The proposed invention for the installation of a fire-protected I-beam column of the building was applied during the reconstruction of the educational building No. 2 of the SASU (Samara, 2011/12).

Information sources

1. Bartellemi B., Kruppa J. Fire resistance of building structures / Per. with french - M.: Stroyizdat, 1985.-216 pp. (Chap. 4, Sec. 4.2 Materials and methods of protection; Fig. 4.2; 4.4 ÷ 4.6; pp. 94-98).

2. Romanenkov I.G., Levites F.A. Fire protection of building structures. - M.: Stroyizdat, 1991. -320 p. (Chap. 4 Structural methods of fire protection; Sec. 4.2. - Large-sized sheet, plate and roll cladding; Fig. 8, p.131 ÷ 133.

3. A.S. SU №887755 MKI-3 E04B 1/94 Building node of the building / Yu.V. Pokrovsky, V.V. Fedorov, M.M. Karabochinsky et al .; application 02.21.80; publ. 12/07/81, Bull. No. 45.

4. A.s.SU No. 773 218 MKI-3 E04B 1/94 Building element / Yu.V. Pokrovsky, V.V. Fedorov, V.V. Filippov; application 04/13/79; publ. 10.23.80, Bull. Number 39.

Claims (13)

1. Fire-resistant I-beam of the building, containing the supporting rod and sheet cladding, characterized in that the supporting rod is made in the form of a steel column I-beam and each end of the steel supporting rod is equipped with fastening nuts and set screws with countersunk heads and screwed-in pointed ends and a straight slot; installation screws are attached to the shelves of the columnar I-beam contact, close to the elements of sheet fire retardant cladding, to the wall of the I-beam are attached contact, close to the elements of the plate fire retardant cladding; the thickness of the cladding elements is determined taking into account the thermal diffusion of its materials, heating conditions and the degree of fire resistance of the building. 2. Fireproof column according to claim 1, characterized in that an anti-corrosion layer is applied to the surface of the steel supporting rod. 3. Fireproof column according to claim 1, characterized in that the elements of the sheet of fire retardant cladding are made of refractory plasterboard sheets. 4. Fire-retardant column according to claim 1, characterized in that the elements of the plate fire-retardant cladding made in the form of piercing mats made of mineral wool. 5. Fireproof column according to claim 1, characterized in that the elements of the fire-retardant plate cladding are made in the form of Rockwool mineral wool plate products. 6. Fireproof column according to claim 1, characterized in that 1 that the length of the screwed end of the set screw into the elements of the fire retardant cladding is adopted at least l _min ≥0.2 · h, here h is the height of the steel column I-beam. 7. Fireproof column according to claim 1, characterized in that on the outer surfaces of the elements of the fire retardant cladding applied a layer of fiberglass. 8. Fireproof column according to claim 1, characterized in that the outer surfaces of the elements of the fire retardant cladding applied plaster. 9. Fireproof column according to claim 1, characterized in that the thickness of the elements of the fireproof lining δ _{o, mp} , mm, is determined by the exponential equation (1):

;
where C is the degree of fire protection of the steel column I-beam, cm;
D _ar is an indicator of thermal diffusion of the cladding material, mm / min;
m _o - an indicator of the heating conditions of the column I-beam (0.5 ÷ 1). 10. Fireproof column according to claims 1 and 9, characterized in that the value of the fire protection limit of a separate layer of fireproof cladding t _{u, co} min, is calculated according to the representative equation (2):
τ _{u, co} = 65 m _o1 (δ _co / D _co ) ^1.41 ;
where m _o1 is an indicator of the heating conditions of the cladding layer, (0.5 ÷ 1);
δ _co - the thickness of a single layer of fire retardant cladding, mm;
D _co - an indicator of thermal diffusion of the cladding material, mm ² / min. 11. Fireproof column according to claims 1 and 9, characterized in that the indicator of the heating conditions of the flange of the column I-beam is calculated by the power equation (3):
m ₀ = 0.7 ^{δx / δy} ;
where δ _x and δ _y are the thickness of the fire protection of the shelf of the column I-beam along the axes X and Y, mm; 12. Fireproof column according to claim 1, characterized in that the ends of the shelves of the columnar I-beam are protected from fire by an asbestos cord. 13. Fireproof column according to claim 1, characterized in that on the surface of the walls and shelves of the columnar I-bead is applied an adhesive layer for additional fastening of the lining.

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