RU2492301C1 - Beam with wall corrugated with asymmetric profile - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: beam with a wall corrugated with an asymmetric profile comprises a compressed and an extended belt and a wall. The wall at least on some sections is traditionally or alternately corrugated with transverse corrugations. The profile of corrugations is asymmetric relative to the plane stretching via the corrugation top and normal to the longitudinal axis of the beam.

EFFECT: increased bearing capacity of a beam.

10 cl, 8 dwg

Description

The invention relates to construction, to supporting structures with the ability to perform enclosing functions, and can be used in industrial and civil buildings and structures.

The prior art I-beam N.P. Selivanova - Patent for the invention RU 2029039 C1. In this beam, the wall is corrugated with a profile with amplitude decreasing towards the lower (stretched) belt. A disadvantage of the known design is the decrease in the overall wall stability and local stability of an individual corrugation due to a change in the height of the wall section of the corrugation, which ceases to work as a transverse stiffener, which is especially important in the supporting sections of the beam. The wall section in the places where bending moments predominate (as a rule, the mid-span section of articulated bending beams) cannot fully be included in the bending work due to the low stiffness of the wall across the corrugations.

The closest analogue (prototype) of the invention according to the technical essence and the achieved effect is a beam with a variable-corrugated wall - Utility Model Patent No. 91583. The constructive solution of the prototype corresponds to changes in the intensity of the main forces arising in a bent beam — bending moments and transverse forces — however, it does not fully realize the potential possibilities of variable wall corrugation. This circumstance is justified by the symmetry of the profile (s) of the corrugations relative to the plane passing through the top of the corrugation and normal to the longitudinal axis of the beam passing along the largest side of the element.

The technical result from the application of the present invention is to increase the bearing capacity of the beam, especially the stability of the shape of its wall.

The specified technical result is a solution to the urgent problem of the effective use of the material in load-bearing building structures. The noted technical result is achieved due to the fact that the wall of the beam, at least in some areas, is traditionally or alternately corrugated mainly by transverse corrugations with a profile asymmetric with respect to the plane passing through the top of the corrugation and normal to the longitudinal axis of the can. Rational areas of corrugation with an asymmetric profile are zones of intense transverse forces and / or torques and significant tangential stresses (usually supporting sections).

At the same time, corrugation of sheet blanks with corrugations with a constant pitch and height is proposed to be considered traditional. It is proposed to consider corrugation of sheet blanks as corrugations with variable pitch and / or height.

A change in the corrugation parameters (pitch and height) with a variable corrugation of the wall corresponds to changes in the intensity of the transverse forces, bending and torques in the beam: in areas of relatively intense transverse forces and / or torques, the step of the corrugations is minimum, and their height is maximum, and in areas with small transverse forces and / or torques - the opposite situation, the step of the corrugations is the maximum, the height of the corrugations is the minimum.

The asymmetry of the profile of the corrugations of the wall lies in the displacement of the tops of the corrugations in the direction of increasing intensity of transverse forces and / or torques. The above design solution allows you to place the top of the corrugation, i.e. a fragment of a single corrugation with the greatest longitudinal and torsional stiffnesses, closer to the maximum (modulo) values of effort in the area of this corrugation. The proposed asymmetric geometric shape of the profile of the corrugations of the wall corresponds to the optimal placement of the corrugation material for a given step and height, based on the principle: the greatest stability of the wall with its least material consumption.

The invention is illustrated by drawings, in which:

figure 1 - beam with a variable-corrugated asymmetric profile wall and with parallel belts of sheet material;

figure 2 is a side view of the beam in figure 1;

figure 3 is a longitudinal section aa in figure 2;

figure 4 - beam with a corrugated asymmetric profile of the wall and with parallel metal-wooden belts;

in Fig.5 is a longitudinal section of the beam in Fig.4;

Fig.6 is a beam with a variable-corrugated asymmetric profile wall having perforation, and with parallel belts, one of which includes reinforced concrete flooring;

Fig.7 is a side view of the beam in Fig.6;

Fig.8 is a longitudinal section aa in Fig.7.

A beam with a corrugated asymmetric profile wall consists of a compressed belt 1 and an extended belt 2 connected by a wall 3. The wall 3 is corrugated mainly by transverse corrugations. A substantially important circumstance is the asymmetric profile of the corrugations in at least some, most often supporting, sections of the beam. The corrugation of the wall 3 can be traditional or variable, it is possible that in some parts of the wall 3, the corrugations have a constant pitch and height, and on others - variable (Figs. 4, 5).

The corrugations can be one-sided and two-sided relative to the median plane of the wall 3. The arrangement of bilateral corrugations is preferable due to a more uniform transfer of forces from the belts 1 and 2 to the wall 3, better torsion work, close correspondence of theoretical design assumptions to the real picture of the conjugation of the beam elements and their force resistance.

The profile of the corrugations can be curved or broken. In some cases, it is possible to consider an asymmetric profile as the corresponding deformation of a wavy, triangular, trapezoidal or other symmetrical profile. It is possible to change the profile of the corrugations along the length of the wall 3, for example, a trapezoidal profile in the supporting sections of the wall, and a triangular and / or wavy profile in the span (Figs. 4, 5).

The scope of the invention provides a variant of the beam, in which corrugations are used, both extending to both edges of the wall 3 and not extending, or corrugations extending to only one edge (blind).

Wall 3 to increase local stability can have, at least in some areas, mainly stamped and aligned with corrugations stiffeners (in fact - additional corrugations 4). Additional corrugations 4 may not go to the edges of the wall 3 or go at least to one of its edges. Additional corrugations 4 are, as a rule, one-sided and symmetrical due to the fact that they are effectively produced using the technology of stamping sheet parts.

The wall 3 may have a perforation 5 (Fig.6, 7), which is preferably provided in the area with a predominant influence of bending moments on the bearing capacity. The perforation device 5 allows in some cases to further reduce the consumption of metal on the wall 3 and to pass communications through the structure.

It is within the scope of the invention that a beam is provided in which, in areas of relatively small transverse forces and torques at intense bending moments, wall 3 is a smooth sheet. A section of the wall 3 for the rational placement of a smooth sheet can be, for example, the span zone of an articulated bending beam (especially with the formation of a zone of clean bending) of the beam.

Alternatively, the wall 3, at least in some areas, contains predominantly transverse metal rolling or bent profiles of open or closed cross section (supporting sections of the wall 3 in FIGS. 4, 5).

These metal profiles form, as a rule, the tops of the corrugations and are connected directly to each other or to intermediate metal plates using a welded, adhesive or rivet joint.

Significant differences of the proposed design from the closest analogue:

- the asymmetric profile of the corrugations allows you to shift the top of the corrugations in the direction of the prevalence of intense transverse forces and shear stresses, in most cases - in the direction of the supports;

- the possibility of organizing type-setting wall 3, which is formed by a set of rolled or bent profiles interconnected, for example, by thin flat plates, which allows: to differentiate the thickness of the wall 3 along the length of the beam;

without additional reinforcement of the wall 3, arrange relatively small holes in it (hole sizes - not more than 1/3 of the height of the wall 3), for example, to pass communications;

increase the torsional rigidity of the beam section;

to produce a beam with a variable and traditionally corrugated wall 3 without specialized corrugating equipment;

- the possibility of forming such a wall 3, in which the local loss of stability of some of its plates does not lead to a limiting state of the structure, but signals a high level of the forces acting in the structure, i.e. it is possible to create a structure with a controlled means of changing the shape of the elements by the level of stresses in the wall 3.

A beam with a corrugated asymmetric profile of the wall 3 may have transverse stiffeners and / or longitudinal stiffeners along the length of the wall 3, as well as end support ribs (not shown conventionally in the drawings).

The high flexibility of wall 3, reaching 500 or more, increases the likelihood of initial deaths (geometric imperfections - deviations from the idealized shape), the negative impact of which is most pronounced in the support sections of wall 3. This fact, as well as the fact that the influence of support reactions are close to the concentrated effect external force, necessitates the installation of support ribs in most cases.

Transverse stiffeners can adjoin the wall 3 and to the belts 1 and 2, or only to the belts 1 and 2. In the latter case, they are actually racks. A variant of the beam is possible, in which the wall 3 is strengthened not only by the posts, but also by the braces. Regarding the wall 3 stiffeners, racks and braces can be either one-sided or two-sided. The two-sided option is effective in the case of strengthening the proposed beam, for example, with an increase in operational load.

Belts 1 and 2 of a beam with a corrugated asymmetric profile of the wall 3 can be parallel or non-parallel to each other, representing a triangular, trapezoidal, polygonal or segmented shape.

The compressed belt 1 and the extended belt 2 of the beam with a corrugated asymmetric profile of the wall 3 can be performed with different cross-sections, it is also possible to change the cross-section of the belts 1 and 2 in length.

The invention provides a variant of the beam, in which the compressed belt 1 is made of several materials: a metal element 6 and reinforced concrete flooring 7, fastened together by anchoring bolts 8 (6, 7).

The cross section of the beam can be I-beam, box-shaped (double wall 3), I-box-shaped (in fact, box-shaped with overhangs of belts 1 and / or 2).

The nature of the work of the beam with a corrugated asymmetric profile of the wall 3 is as follows:

when loading the beam with an external load acting on one or two belts 1 and 2 and directed in the plane of the wall 3, a transverse bending of the structure is observed. In the beam, efforts arise mainly from transverse forces, bending and torques. The transverse forces are perceived almost completely by the wall 3, and bending moments - almost completely by the belts 1 and 2. The forces from the torques are perceived by the belts 1, 2 and the wall 3.

If reinforced concrete flooring 7 is arranged on top of the beams, then it is included in the work of the compressed belts I for compression and torsion, thereby significantly reducing their material consumption. The stability of the compressed belt 1 is improved in places where it adjoins the corrugated sections of the wall 3, due to which they rely on a conditional strip with a width equal to the height of the corrugations.

The I-beam with a corrugated asymmetric profile of the wall 3 in torsion resistance (torsional stiffness) occupies an intermediate position between the I-beam smooth-walled (with transverse stiffening ribs) and box-shaped beams. Increased torsion resistance allows you to apply a bending load with eccentricities reaching half the height of the corrugations.

The stability of the beam from the plane is ensured by unfastening it with ties in the form of struts and girders, a continuous flooring in the form of a reinforced concrete slab, profiled or flat metal sheet, etc.

The proposed beam has, as a rule, a hinged bearing at the ends, although a continuous multi-span beam scheme is not excluded.

The corrugation of the wall 3, as well as the installation (if necessary) of stiffeners, end (support) ribs and / or a system of braces and / or racks prevents the loss of stability of the wall 3. In the case of smooth sections of the wall 3 in the zones of intense bending moments, these sections are turned on in the work of the belts 1.2 bending.

The support reaction from the beam is transmitted to the downstream vertical load-bearing elements of the structure (walls, columns, pylons) and then to the foundations.

A beam with a corrugated asymmetric profile of the wall 3 is made, as a rule, of metals, mainly from steels of ordinary or high strength groups. Due to the fact that bending moments are perceived mainly by belts 1 and 2, it is possible to make them from metals with different physical and mechanical properties (in particular, the bistal solution). Wall 3 is connected to belts 1 and 2 using continuous, single or double-sided welds, which requires consideration of weldability and operating conditions.

Perhaps a metal-wooden solution of the belts (Fig. 4), which is a wooden beam 9 and a metal profile 10 (bent or rolled) joined into a single supporting element. This design solution allows you to connect the wall 3 with the belts 1 and 2 by gluing it into the grooves arranged in the wooden beams 9. The connection of the beam 9 with the profile 10 can be carried out using glue, nails or bolts (including through) .

In the case of manufacturing a beam from non-metallic materials (plastics, composite materials, etc.), the joining of the elements of the beam is carried out mainly using adhesive solutions.

Conventional or variable corrugation can be carried out using stamping technology - pressing blanks between two dies, rolling on profiling mills, bending with roll forming machines, and also combining these methods. Preference should be given to production with the highest degree of automation, bringing the greatest economic effect. It should be borne in mind that the device of stiffeners, end support ribs, braces and racks significantly complicates, and in some cases violates the complete automation of production lines for the production of composite structures.

The scope of the invention: structural systems of load-bearing elements of buildings and structures for civil and industrial use, The invention can be used in various snow, wind and seismic areas. The proposed design is designed to perceive static or dynamic effects. Under dynamic loads, it is recommended that this beam be made of steel (compressed belt 1 may include reinforced concrete flooring 7 - Figs. 6, 7), and the connection of belts 1 and 2 with wall 3 should be carried out using continuous bilateral welds.

The design parameters of a particular beam (the profile shape of the corrugations, their pitch, height; sections and material of the beam elements, its overall dimensions, etc.) are assigned based on the working conditions of the structure, a comprehensive task for its design, and the results of calculations of bearing capacity and performance. For carrying out calculations of the bearing capacity, it is recommended to use numerical methods of the theory of elasticity, in particular, the finite element method (FEM) in a computer implementation.

A feature of the calculations is to take into account the fact that the loss of stability of some elements of the beam (primarily wall 3) is very likely in the elastic stage of the material. A case is possible when the loss of the bearing capacity of the beam is caused by the loss of local stability of its elements and occurs at stresses in the elements below the yield stress, and in some cases even below the proportionality limit of the elastic-plastic material of the beam elements.

When calculating beam stability, it is recommended to analyze not only the first form of buckling, but also the subsequent ones. In many (but not all) cases, it is permissible to carry out calculations under the assumption of elastic work of the beam material.

When carrying out computer calculations by the finite element method, it is recommended to use shell finite elements when modeling the beam, taking into account the geometric and physical non-linearities of the work. Moreover, an essential criterion for the adequacy of the calculation model is its maximum similarity with the full-scale design both in geometric characteristics and in stiffness parameters.

Claims (10)

1. A beam with a corrugated asymmetric profile wall, containing a compressed and stretched belt and a wall, characterized in that the wall, at least in some areas, is traditionally or alternately corrugated mainly by transverse corrugations with a profile asymmetric with respect to the plane passing through the top of the corrugation and normal to the longitudinal axis of the beam. 2. A beam with a corrugated asymmetric profile wall according to claim 1, characterized in that the wall has, at least in some areas, mainly stamped and aligned with the corrugations stiffeners (essentially additional corrugations) that do not extend to the edges of the wall or exit at least one of its edges. 3. A beam with a corrugated asymmetric profile wall according to claim 1 or 2, characterized in that in areas of relatively small transverse forces and torques, but intense bending moments, the wall is made of a smooth sheet. 4. A beam with a corrugated asymmetric profile wall according to claim 3, characterized in that the profile of the corrugations varies along the length of the wall. 5. A beam with a corrugated asymmetric profile wall according to claim 4, characterized in that the compressed and stretched belts are not parallel to each other, while the outline of the belts is a triangular, trapezoidal, polygonal or segmented shape. 6. A beam with a corrugated asymmetric profile wall according to claim 5, characterized in that the compressed and stretched belts are made with different cross sections and / or from different materials. 7. The beam with the corrugated asymmetric profile of the wall according to claim 6, characterized in that the wall, at least in some areas, contains transverse located mainly metal rolling or bent profiles of open or closed cross section. 8. A beam with a corrugated asymmetric profile of a wall according to claim 7, characterized in that along the length of the wall, transverse and / or longitudinal stiffeners and / or end support ribs and / or a system of struts and / or braces are provided. 9. A beam with a corrugated asymmetric profile wall according to claim 8, characterized in that perforation is provided in the wall. 10. A beam with a corrugated asymmetric profile wall according to claim 9, characterized in that the wall thickness is variable along the length.

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