RU2767006C1 - Metal frame of building or structure - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to construction, namely to metal frames of buildings and structures for various purposes. Metal frame of the frame consists of columns and crossbars resting on them. Columns and crossbars are made in the form of welded structures consisting of a corrugated wall rigidly connected to two belts. Each belt in cross section is represented by central rectilinear section l₁, perpendicular to corrugated wall, length of which is formed by double amplitude of corrugated wall profile and legs of welded seams, and symmetrical right and left overhangs, each of which in cross section of frame elements consists of three successively conjugated sections (l₂, l₃, l₄), which are conjugated by sections l₂ with central rectilinear section l₁. Each of the three successively conjugated sections (l₂, l₃, l₄) has a curvature radius.

EFFECT: higher bearing capacity.

4 cl, 13 dwg

Description

Technical field

The invention relates to construction and is intended primarily for use as load-bearing frames of industrial, civil, agricultural buildings and structures, consisting of columns and crossbars based on them.

State of the art

Known beam (crossbar) composite welded I-section, consisting of two parallel oriented belts of sheet metal with perpendicular welded to them thin-walled transversely corrugated wall (RU 76936 U1, 10.10.2008).

The disadvantages of the claimed technical solution of the analogue is that the beam belts are made in the form of thin sheet flat elements (plate).

It is known that when a beam is bent, the upper chord is compressed, while the lower chord is stretched. One of the main parameters of the bearing capacity of the compressed beam chord is local buckling (local buckling of the chord under the action of compressive stresses). In the analogue, the belts are made in the form of ordinary plates, which have a reduced ability to resist local buckling, as a result of which the considered beam design has a low bearing capacity according to the criterion of "local stability" of the compressed belt.

Known metal welded column, represented by a thin-walled transversely corrugated wall and two belts of sheet metal with (RU 56429 U1, 10.09.2006).

The disadvantages of the claimed technical solution of the analogue is that the chords of the column are made in the form of flat sheet metal (plate).

One of the main parameters of the bearing capacity of columns is the local stability of the chords - that is, the ability of the chords to resist compressive forces without losing local stability (local buckling of the chords under the action of compressive stresses). The column chords are made in the form of ordinary plates, which have a reduced ability to resist local buckling, as a result of which the column design under consideration has a low bearing capacity according to the "local stability" criterion of the compressed chord.

The closest technical solution chosen as a prototype is the metal frame of the building frame, where the columns and crossbar are made of welded structures, represented by a transversely corrugated wall and belts in the form of thin-walled bent profiles https://msm24.ru/upload/medialibrary/61e/ 61e5220858fb2817a01ba65f62ba250d.jpg, https://msm24.ru/upload/medialibrary/276/276be5719b190b6b2c3c3cc7ed60b3e2.jpg .

The columns and crossbar of the prototype frame are manufactured according to TU 24.1.74-001-21862579-2017. Welded steel beams with a corrugated web and belts made of bent profiles for building structures. Specifications https://msm24.ru/sprav/tekhnicheskie-kharakteristiki-balok-gbgp-proizvodstva-zao-magsibmet.html, https://msm24.ru/sprav/effektivnye-konstruktsii-gofrobalok-dlya-lyegkikh-metallokarkasov- zdaniy.html, https://msm24.ru/portfolio/karkas-zdaniya-razmerom-18kh40-5kh6-m-krasnoyarsk-ul-pogranichnikov.html .

Columns and crossbars of metal frames of the prototype are welded structures consisting of transversely corrugated walls and belts of bent thin-walled profiles rigidly connected to them by welding. Each belt of columns and crossbars of the considered frames in section consists of (Fig. 2):

- the central section l ₁ , based on the corrugated wall and connected to it by welding, while the length of the section l ₁ is determined by the doubled amplitude of the corrugated wall and the dimensions of the legs of the welds;

- and symmetrical right and left overhangs (l₂,l₃,l₄) in the form of segments l₂, adjoining on both sides to the section l_one, two segments l₃ given bending radius R_onelocated on both sides of the sections l₂and associated with them, two sections l₄, which are continuations of segments l₃.

The disadvantages of the frame of the prototype is the low bearing capacity of the belts of the columns, crossbar according to the criterion of "local stability", due to the presence of flat sections of the overhangs of the belts l ₂ and l ₄ .

Disclosure of the essence of the invention

The technical result of the claimed invention is to increase the bearing capacity of columns and crossbars of metal frames of buildings and structures according to the criterion of "local stability" of the belts.

The claimed technical result is achieved by the fact that in the metal frame of the frame of a building or structure, consisting of columns and crossbars based on them, the columns and crossbars are made in the form of welded structures, which consist of a corrugated wall, height H, rigidly connected to two belts, each of which in cross section is represented by a central straight section l ₁ perpendicular to the corrugated wall, the length of which is formed by a double amplitude of the profile of the corrugated wall and the legs of the welds, and symmetrical right and left overhangs, each of which in the cross section of the frame elements consists of three successively paired with each other sections (l ₂ , l ₃ , l ₄ ), which are connected by sections l ₂ with the central straight section l ₁ , while each of the three sections of the overhangs of the belts (l ₂ , l ₃ , l ₄ ) connected in series with each other has its own radius of curvature .

At the same time, the radii of curvature of three successively paired sections (l ₂ , l ₃ , l ₄ ) of the cross sections of the overhangs of the chords of the columns and crossbars of the frame can have variable radii of curvature along the length, decreasing at the beginning of the sections l ₂ , from the points of junction with straight sections l ₁ with R ₂ ≤ N/2÷N and at the end of sections l ₄ to R ₄ ≤ (l ₂ + l ₃ ) ÷ l ₃ .

As an option for the execution of the belts, the radii of curvature of three sections of the overhangs of the belts (l ₂ , l ₃ , l ₄ ) of the cross sections of the columns and crossbars of the frame that are successively paired with each other can have a constant radius of curvature R ₁ ≤ (l ₂ + l ₃ ) along the length.

A variant of the technical solution is also possible, when the radius sections l₄cross sections of overhangs of belts columns and crossbars of the frame have a constant radius of curvature R₄ ≥ 2t_P with a central angle of 360 degrees minus the technological angle of back springback, where t_Pis the thickness of the corresponding belt.

As a result of the proposed structural transformations of the technical solution of the frame of the prototype, the overhangs of the chords of the proposed solution of the columns and crossbars of the frame are fragments of cylindrical shells of variable or constant curvature.

It is a well-known fact that flat plates working in compression in the longitudinal direction have a significantly lower bearing capacity according to the criterion "longitudinal stability" in comparison with longitudinally compressed cylindrical shells (Birger I.A. Rods, plates, shells. Publishing house URSS, 2019 - 392 p.).

It is the replacement in the frame of the prototype of flat sections of the overhangs of the chords of columns and crossbars with fragments of cylindrical shells of variable or constant curvature that has the effect of increasing the bearing capacity of the structures that make up the frame according to the criterion of "local stability" of the compressed chords.

Brief description of the drawings

The invention is illustrated by the attached drawings, where

in fig. 1 shows a metal frame, general view,

in fig. 2 shows sections A-A, columns and B-B crossbars of the prototype solution frame,

in fig. 3, 4, 5 shows sections of the proposed technical solution for columns A-A, crossbars B-B of the frame (options),

in fig. 6, 7 show the calculation results for the columns of the prototype solution and the proposed technical solution in the SP LIRA-SAPR, respectively,

in fig. 8 shows fragments of calculated frame columns,

in fig. 9, fig. 10 (enlarged fragment) shows the result of calculation of the crossbar of the prototype solution in the SP LIRA-SAPR,

in fig. 11, fig. 12 (enlarged fragment) shows the result of the calculation of the crossbar of the proposed technical solution in the SP LIRA-SAPR,

in fig. 13 shows fragments of the calculated crossbars of the frame.

Implementation of the invention

- in Fig. 1 shows a metal frame consisting of columns and crossbars resting on them with the designation of sections of columns A-A and crossbars B-B;

- in Fig. 2 shows sections A-A, columns and B-B crossbars of the prototype solution frame, where the belts of the structures of columns and crossbars are bent thin-walled profiles, consisting in section of:

- the central section l ₁ , based on the corrugated wall and connected to it by welding, while the length of the section l ₁ is determined by the doubled amplitude of the corrugated wall and the dimensions of the legs of the welds;

- and symmetrical right and left overhangs (l₂,l₃,l₄) in the form of segments ᶩ₂, adjoining on both sides to the section l_one, two segments l₃ given bending radius R₃located on both sides of the sections l₂and two segments associated with them l₄, which are continuations of segments l₃;

in fig. 3 shows the sections of the proposed technical solution for the columns A-A and the crossbars B-B of the frame, where each of the three sections of the sections of the overhangs of the belts (l ₂ , l ₃ , l ₄ ) connected in series with each other has its own radius of curvature, or each of the three in series sections of the sections of the overhangs of the belts (l ₂ , l ₃ , l ₄ ) conjugated with each other has a variable radius of curvature along the length, decreasing at the beginning of the sections l ₂ , from the points of junction with straight sections l ₁ with R ₂ ≤ H / 2÷H and in end of sections l ₄ to R ₄ ≤ (l ₂ + l ₃ ) ÷ l ₃ ;

- in Fig. 4 shows sections of the proposed technical solution for columns A-A, crossbars B-B of the frame, with radius sections of overhangs of both belts (l₂,l₃,l₄), having a constant radius of curvature R₂≤ (l₂+l₃);

- in Fig. 5 shows sections of the proposed technical solution for columns A-A and crossbars B-B of the frame, where the radius sections of the overhangs of both chords l ₄ have a constant radius of curvature R ₄ ≥ 2t _p with a central angle of 360 degrees minus the technological angle of back springing, where t _p - thickness of the corresponding belt of columns and crossbars of the frame.

According to the results of preliminary calculations, the proposed technical solutions for columns and crossbars of frames with the replacement, in comparison with the prototype, of flat sections of overhangs of belts with fragments of cylindrical shells, has from 1.5 to 2 or more times increased bearing capacity of frame structures (columns, crossbars) according to the criterion " local stability” of belts.

At the same time, the technology for manufacturing frame structures (column, crossbar) with sectional shapes according to the proposed technical solution practically does not differ from the technology for manufacturing frame structures with prototype sections.

To prove the effect of increasing the bearing capacity of the frame structures (column, crossbar) with the proposed technical solution of the chords, in comparison with the prototype, calculations were performed in the LIRA-SAPR software package (hereinafter SP LIRA-SAPR) according to the criterion of "local stability" of the chords. The elements of structures calculated in SP LIRA-SAPR were modeled by plate elements of appropriate thicknesses.

As a result of the calculation, the criterion of local buckling of the compressed chords of columns and girders was compared with the sections adopted in the prototype frame and the variant of the sections of the structures of the columns, girders of the proposed technical solution.

As a criterion for local buckling of design chords of crossbars and columns in SP LIRA-SAPR calculates the value of the coefficient of local buckling k _st of compressed chords of structures.

The stability coefficient _kset in SP LIRA-SAPR, as in any finite element software package, shows how many times the applied external load differs from the critical one according to Euler (ideal mechanical systems), causing the loss of stability of the calculated element (loss of the rectilinear form of equilibrium with the transition to Curvilinear Equilibrium State SP LIRA-SAPR Volume I Main Features FE Library Application Examples https://www.liraland.ru/public_private/lira/Verification/LIRA-SAPR_Verification_vol-1.pdf .

In comparative calculations of the frame structures of the proposed technical solution and the solution of the prototype, a column and a crossbar with the same column height and crossbar span equal to 4.0 m, the same cross-sectional dimensions and element thicknesses are taken: the corrugated wall in the calculated column and crossbar is taken to be sinusoidal with a wave amplitude of 20 mm and corrugation pitch 140 mm, wall height 500 mm in full compliance with the prototype solution according to TU 24.1.74–001–21862579–2017 https://msm24.ru/sprav/tekhnicheskie-kharakteristiki-balok-gbgp-proizvodstva-zao -magsibmet.html.

At the same time, in the calculated column and crossbar of the proposed frame solution, the sections of the overhangs of the chords in the section (l ₂ , l ₃ , l ₄ ) had variable radii of curvature along the length, decreasing at the beginning of the sections l ₂ , from the points of conjugation with straight sections l ₁ with R2 = 250 mm and at the end of sections l ₄ to R ₄ = 50 mm with a thickness of the belts t _p = 3 mm.

The crossbar of the floor of the first floor according to Fig. 1 with a split scheme of support on the column, with support ribs with a section of 120x8 mm.

In the calculated columns, the lower support node is represented by a rigid fastening of the column in the foundation, and the upper support of the columns is, in order to simplify the calculation, hinged and movable in the vertical direction.

At the same time, in the calculations, the columns were loaded in the form of a centrally applied compressive load of 50 tf, and the crossbars were loaded in the form of a uniformly distributed load of 10 tf/m in the wall plane.

In SP LIRA-SAPR, modeling and calculation of the structures under consideration for local stability were performed.

In FIG. Figure 6 shows the result of calculation in the SP LIRA-SAPR of a column with a prototype section - the first form of loss of local stability of the compressed chords of the calculated column is shown, the coefficient of the first form of the loss of stability of the chords is k set = _3.049 . In this case, the critical load of the centrally loaded column, corresponding to the first form of local buckling of the belts, is 50 tf * 3.049 = 152.45 tf.

In FIG. Figure 7 shows the result of the calculation in SP LIRA-SAPR of a column with a section of the proposed technical solution - the first form of local buckling of the chords is shown, the obtained coefficient of the first form of buckling of the compressed chords is equal to k _set = 5.35. In this case, the critical load of the centrally loaded column, corresponding to the first form of loss of local stability of the compressed chords, is 50 tf * 5.35 = 267.5 tf.

In FIG. 8 shows fragments of calculated frame columns.

Thus, as a result of the calculation in SP LIRA-SAPR, the effect of increasing the bearing capacity of the chords of column structures with the cross section of the proposed technical solution of the frames was obtained in comparison with the prototype solution according to the criterion "local stability" of the chords by 5.35/3.049 = 1.75 times, that is, the bearing capacity of the structures of the proposed solution of the frame columns is increased by 75%.

Frame crossbars were calculated similarly in SP LIRA-SAPR.

In FIG. 9, fig. 10 (enlarged fragment of the crossbar) shows the result of the calculation in the SP LIRA-SAPR - the first form of local buckling of the girder of the frame of the prototype frame is shown, the coefficient of the first form of local buckling of the compressed girder of the crossbar is k _set = 2.22. In this case, the critical load corresponding to the first form of local buckling of the compressed belt is 10 tf/m*2.22 = 22.2 tf/m.

In FIG. 11, fig. 12 (an enlarged fragment of the crossbar) shows the result of the calculation in the SP LIRA-SAPR - the first form of local buckling of the compressed girder of the frame of the proposed technical solution is shown, the coefficient of the first form of local buckling of the compressed girder of the crossbar is k _set = 4.31. In this case, the critical load corresponding to the first form of local buckling of the compressed girder is 10 tf/m*4.31 = 43.1 tf/m.

In FIG. 13 shows fragments of the calculated crossbars of the frame.

As a result of the calculation of frame crossbar structures in SP LIRA-SAPR, the effect of increasing the bearing capacity of the frame crossbar with the section of the proposed technical solution was obtained in comparison with the prototype solution according to the criterion of "local stability" of the compressed belt by 4.31 / 2.22 = 1.94 times , that is, the bearing capacity of the structures of the proposed solution of frame crossbars is increased by 94%.

Thus, the above design features of the claimed invention make it possible to increase the bearing capacity of the metal frame structures of the frame of a building or structure, which is confirmed by calculations in a specialized software package (SP LIRA-SAPR).

Claims (4)

1. The metal frame of the frame of a building or structure, consisting of columns and crossbars resting on them, characterized in that the columns and crossbars are made in the form of welded structures, which consist of a corrugated wall with a height of H, rigidly connected to two belts, each of which is in the transverse section is represented by a central rectilinear section l ₁ perpendicular to the corrugated wall, the length of which is formed by a double amplitude of the profile of the corrugated wall and legs of welds, and symmetrical right and left overhangs, each of which in the cross section of the frame elements consists of three successively mated sections (l ₂ , l ₃ , l ₄ ), which are conjugated by sections l ₂ with a central straight section l ₁ , while each of the three successively paired sections (l ₂ , l ₃ , l ₄ ) has a radius of curvature. 2. The metal frame of the frame of a building or structure according to claim 1, characterized in that the radii of curvature of three successively mated sections (l ₂ , l ₃ , l ₄ ) of the cross sections of the columns and crossbars of the frame have variable radii of curvature along the length, decreasing in the beginning of sections l ₂ , from the points of junction with straight sections l ₁ with R ₂ ≤Н/2÷Н and at the end of sections l ₄ to R ₄ ≤(l ₂ +l ₃ )÷l ₃ . 3. The metal frame of the frame of a building or structure according to claim 1, characterized in that the radii of curvature of three consecutive sections (l ₂ , l ₃ , l ₄ ) of the cross sections of the columns and crossbars of the frame have a constant radius of curvature R ₄ ≤ (l ₂ + l ₃ ). 4. The metal frame of the frame of a building or structure according to claim 1, characterized in that the radius sections l _{4 of} the cross sections of the columns and crossbars of the frame have a constant radius of curvature R ₄ ≥2t _p with a central angle of 360 degrees minus the technological angle of back springing, where t _n is the thickness of the corresponding chord of the column or frame crossbar.

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