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Dome structures
World construction experience shows that domes are one of the effective forms of spatial structures. They turn out to be the most rational when covering large spans. So, if flat structures with a span of up to 40 m can still compete with dome ones in terms of metal consumption, then with an increase in the span, the advantage of dome ones is obvious. The efficiency of these structures increases with increasing span and it is no coincidence that most roofs over 200 m are domed. The compositional possibilities of such structures are also great. They make it possible to cover multipurpose buildings and create beautiful examples of architectural creativity.
Dome structures have been known since ancient times. They were used in Mesopotamia, Syria, Iran, Ancient Rome. The main material was stone. The first metal domes appeared at the end of the 19th century. The main credit for the development of these structures belongs to Feppel and Schwedler. In the 20th century, significant contributions to the development dome structures contributed by Lederer, Makovsky, Otto, Wright, Fuller, Tupolev M.S., Lipnitsky M.E., Savelyev V.A.
Domes are spacer systems that, as a rule, contain three main structural elements: a lower support contour, a shell, and an upper support contour.
Let's consider the main typologies of metal domes:
· a) by design: ribbed, ribbed-ring, ribbed-ring with ties, mesh, plate;
· b) by shape): spherical, elliptical, lancet, umbrella and other shapes;
Structural diagram domes: 1 - upper support contour; 2 - shell; 3 - lower support contour
Shapes of domes: a - plan of a spherical dome; b - cross section of a spherical dome; v-plan elliptical dome; d - cross section of the elliptical dome; d - pointed dome; e - plan of the umbrella dome; g - view of the umbrella dome
· c) along the lifting boom: lifting (high) domes, with a lifting boom of 1/2...1/5 of the diameter and flat, with a lifting height of 1/5 of the diameter.
Ribbed domes consist of individual flat ribs placed in a radial direction. With straight ribs, pyramidal or conical domes are formed. The upper belts of the ribs make up the surface of the dome; at its apex they are adjacent to the upper ring. Sometimes, with a frequent arrangement of ribs or a device at the top of the lantern dome, the ring turns out to be of considerable size; then, in order to increase rigidity and stability, it is fastened with internal struts in at least two diametrical planes.
Geometric parameters of the dome: D - diameter; f - lifting height
The support ring is designed in plan to be curved around a circle or in the form of a polyhedron with rigid or hinged connections at the corners. With a sufficiently frequent arrangement of ribs, it is possible to construct a round ring. With sparsely spaced ribs, it is better to design the support ring polygonal to avoid bending and torsion. The most common is a rigid polygonal ring with supports in the corners that are mobile in the radial direction. Special floorings are usually laid between the ribs or a membrane covering is created. Membrane or panel coverings provide overall stability of the ribs in the plane of the covering, reducing the effective length of the ribs. It is possible to construct a roof along ring girders between the ribs.
Ribbed-ring domes. The design and inclusion of ring girders in the design results in the creation of a ribbed-ring scheme. The latter can be used as dome tightening. In this case, the rings not only act on local bending from roof loads, but also perceive normal forces from the dome ribs, and in the case of a rigid connection of the rings with the ribs, also bending moments. However, due to the low rigidity of the rings and ribs in planes tangent to the surface of the dome, the influence of the rigidity of the nodes can be neglected and it can be assumed that the rings are hinged to the ribs.
Ribbed-ring domes with ties represent a further increase in the connectivity of the system, spatiality of work, by introducing braces between the ribs into the design.
Mesh domes are formed if, in a ribbed-ring dome with connections, the connectivity of the system is increased until the formation of cross connections in each cell of the dome; this is precisely the design represented by the Schwedler dome, which is one of the first mesh domes.
Another definition of a mesh dome is possible, as a polyhedron inscribed in a spherical or other surface of rotation and consisting of one or two layers of structural elements forming a triangular, diamond-shaped, trapezoidal, pentagonal and hexagonal mesh. Such domes are also called geodesic or crystalline in a number of literary sources. Mesh domes usually only have a bottom support ring.
The founders of geodetic and crystal systems are prof. M.S. Tupolev (Russia) and R.B. Fuller (USA). Mesh domes are the most economical in terms of material consumption due to the spatial operation of the frame and the uniform distribution of material over the surface of the shell.
Plate domes assembled from metal plates (panels) that have stamped stiffening ribs connected to each other along the contour by welding or node connections.
Principles of dome formation
The formation of ribbed, ribbed-ring and ribbed-ring with connected domes comes down to determining the shape and coordinates of a flat arch formed from two diametrical ribs. The shape of the arch is determined at the stage architectural design, coordinates are calculated using known formulas of analytical geometry.
The formation of mesh and plate domes is a more complex process. Therefore, let us dwell on this issue in more detail.
The selection and calculation of the geometric scheme of the dome is the first and very important stage of design, since the number of standard sizes of elements, the design of interface nodes, methods of manufacturing and installation of elements and, ultimately, the efficiency of the structure depend on this.
In the process of shaping the surface of the dome, three stages can be distinguished: 1) selection of the surface; 2) choice of cutting method (the term “cutting” refers to the method of applying a network of geometric lines of the dome frame to the selected surface); 3) calculation of node coordinates.
The surfaces of mesh shells are mainly limited to two classes: parallel transfer surfaces (elliptical paraboloid, circular transfer surface, hyperbolic paraboloid) and rotation surfaces (sphere, etc.).
The predominant number of mesh domes are built on a sphere, so further consideration of the issues of forming mesh domes will be carried out based on constructions on a sphere.
For shells of revolution, a meridional-ring cutting system is often taken as a basis. The essence of this system is to divide the surface of rotation by meridional and parallel planes into triangular (at the pole) and trapezoidal elements.
The number of standard sizes of triangular and trapezoidal elements with this cutting system is determined by the number of tiers between parallel sections and does not depend on the number of meridional sections, as well as on the shape of the meridional generatrix of the curve. When forming spherical mesh shells on a plan close to a rectangular one, a network of meridians is also used, formed by the intersection with the sphere of two beams of planes with mutually perpendicular axes. As can be seen from the diagram, the number of standard sizes of elements with such a cutting is much greater than with a meridional-ring system.
The most widespread of the mesh shells of rotation are mesh spherical domes on a round and polygonal (inscribed in a circle) plan. The cutting systems for such domes are varied. Two main stages in the construction of these systems can be distinguished. First, the spherical segment is initially divided into a certain number of identical sections, and then each resulting section is finally cut into smaller ones. The primary breakdown is mainly carried out according to the meridional scheme or according to the schemes of regular and semi-regular polyhedra.
Star system. The primary breakdown of such a system is meridional. A network of meridians is applied to the spherical segment. Each resulting area is divided into quadrangular cells in such a way that two opposite nodes of the cell are located on the same meridian, and the other two are located on the same parallel.
dome sphere design geometric
Formation of the dome grid according to the method of cutting the sphere: a - meridional-circular cutting; b - cutting a sphere by two beams of meridional planes with mutually perpendicular axes
Two types of networks used for this cutting system can be constructed - the regular Chebyshev network and the rhoxodrome network.
The use of the correct Chebyshev network leads to a thickening of the grid as it approaches the pole of the dome. The use of a network of loxodrals (lines having a constant angle of inclination to the meridian) partially eliminates this disadvantage, however, a significant reduction in the length of the lateral sides of the triangles also causes a thickening of the network.
Star system: a - based on the Chebyshev network; b - based on a network of rhoxodromes
In a star system using a Chebyshev network, the length of the rods along the network lines is constant, although changing the angles between the rods leads to the fact that the number of node elements is equal to the number of tiers. With loxodromic cutting, on the contrary, nodal elements can be of the same standard size, and the number of standard sizes of rods located along the network lines can be equal to the number of tiers.
Kaywitt system. This system eliminates the main disadvantage of the star system - grid condensation. The primary breakdown is meridional. The base of each resulting sector is divided into a certain number of equal sections, and then ring sections are made, the number of which is equal to the number of divisions of the base. Each annular section is divided into equal parts, the number of which in each subsequent section, counting from the base of the sector, is reduced by one. The resulting points are connected and thus a network of triangles is obtained, the bases of which along each tier, as in the star system, are equal. However, the triangles formed in this way, unlike the star scheme, are not isosceles, therefore the number of their standard sizes corresponds to the square of the number of divisions (tiers).
System« Romb- 1 » . The essence of this system lies in the primary meridional division of the dome into sectors with the subsequent division of each sector into diamond-shaped cells by applying the correct Chebyshev network. If in a star scheme the opposite nodes of a network cell are located on meridians or, respectively, on parallels, then in this system the lines of the Chebyshev network of various directions are located along the sides of the sector.
As a result of this breakdown, a fairly uniform network of isosceles triangles is obtained, the number of standard sizes of which is approximately two times less than in the Kaiwitt system. The Romb-1 system was used, in particular, in the design of a dome with a diameter of 65 m in Dushanbe.
Unlike the star system and the Kaywitt system, the bases of the dome sectors do not coincide with the annular sections and form a spatial (non-planar) curve. Therefore, the formation of circular coatings using this system is difficult.
Systems based on the use of polyhedra inscribed in a sphere. Domes based on this system are cut out from a sphere, the primary division of which is carried out along geodesic lines drawn through the vertices of inscribed polyhedra.
The dodecahedron (12 pentagonal faces) and the icosahedron (20 triangular faces) are usually used as such polyhedra.
For spherical domes of great height, it is rational to use the symmetry of the regular polyhedra of the icosahedron and dodecahedron. They have ten triple rotation axes and six tenth order mirror rotation axes. Suggested large number options for constructing spherical networks using the symmetry of regular polyhedra. In design practice, two methods are most widespread: a geodetic network based on a dodecahedron; construction of a 720-hedron based on a truncated icosahedron.
Nodal connections of dome elements
The economic efficiency of the dome design is largely determined by the design of the hub connection, which should provide sufficient load-bearing capacity, low labor intensity of manufacturing and assembly, and low material consumption. The design of the nodal connection depends on the geometric design of the dome frame. In the process of designing units, it is important to ensure the axial transfer of forces to the dome elements.
The most important and complex unit in the design of domes of all types is the unit of attaching ribs or rods to the lower ring and supporting the ring on the underlying structures. The lower stretched ring is usually designed in the form of a welded I-beam. In ribbed and ribbed-ring domes, to increase the bending rigidity of the ring in the horizontal plane, the I-beam is placed lying down.
Mesh domes themselves have greater spatial rigidity in the horizontal direction, so when designing them, they tend to develop the support ring vertically. The vertical arrangement of the I-beam also provides maximum rigidity for the perception of radial torques evenly distributed around the ring.
The assembly must be correctly centered - the axes of the dome rods adjacent to the ring and the axis of the vertical support reaction must intersect in a horizontal plane passing through the center of gravity of the ring. In this case, the center line of the ring does not have to pass through the center of the node - the actual diameter of the ring can be slightly reduced or increased.
The ring is usually hinged on a foundation or vertical columns. In long-span domes, it is desirable to ensure freedom of movement of the ring in the radial direction. This is achieved by using roller supports or short swinging posts.
The support ring may have a circular outline in plan, but most often it is a regular flat polygon with rigid or hinged joints of the rods in the corners. The support ring with an axis in the form of a circle is eccentrically stretched.
Below are some possible types of support rings. In all cases, the ring must rest on the underlying base and be immutable.
In order to prevent sliding along the generatrix, rollers are arranged with flanges, and when the rods are swinging, connections are installed normal to the plane of movement of the supports. The orientation of the roller axes is carried out in such a way that the ring is unchanged. For this, any chaotic arrangement of rollers is sufficient, but ordered systems are preferable.
In the analysis of the kinematic scheme and in determining the forces in the elements of the ring for a number of the above schemes, the arrangement of ideal hinges is assumed at the nodes. In reality, the nodal connections are designed to be rigid and there are no hinges. This leads to the fact that bending moments arise in the plane of the ring due to changes in the angles between the rods of the support ring.
The movement of the support ring units under the influence of external loads and temperature changes is accompanied by overcoming rolling friction forces, and sometimes sliding friction forces, which depends on the movement pattern and design of the moving supports. As a result of this, force and couple in the plane of the ring are additionally applied to the ring at each node.
For a support ring stretched by significant forces, the additional normal force from the action of friction forces (tensile - when the temperature decreases, compressive - when the temperature increases) will not cause significant change basic stress state. As for bending moments, their effect turns out to be more significant, since the ring rods are low-rigid in bending in the horizontal plane.
When selecting ring sections, these forces must be taken into account. It is necessary to strive for an arrangement of the rollers in which there would be no change in the angles between the ring rods under polar-symmetrical influences and, if possible, no bending moments from sliding friction forces would arise.
Based on the analysis of the considered support ring design systems, we can come to the conclusion that from the point of view of immutability the best option The location of the supports is a “beam” system. Its immutability becomes more reliable than in centrally symmetrical systems with an increase in the number of sides of the ring, which corresponds to domes of large diameters.
Assemblies of ribbed, ribbed-ring, ribbed-ring with braced domes, predominantly manufactured in construction, are distinguished by their massiveness, mainly bolted, welded, or combined. It is difficult to ensure the concentration of forces for these nodes.
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The most widespread, both in our country and abroad, are domes made of steel structures, less often - of aluminum alloys. Both can cover significant areas; the choice of materials for their construction is dictated by technical and techno-economic considerations. The variety of design solutions allows, in some cases, the use of external stamped and prestressed dome skins as load-bearing and enclosing elements, which leads to significant savings in material during their construction. Below are the main types of dome design solutions.
According to their design, domes can be of various types: ribbed, ribbed-ring, ribbed-ring with ties, mesh and plate. The design of ribbed domes consists of three main elements: a lower support ring, radially arranged flat ribs and an upper support ring. Flat radial ribs are connected to each other at the apex using an upper ring, and at the bottom they usually rest on a lower support ring. In this case, the components of the support pressure from the ribs to the foundations will be only vertical. The horizontal component is perceived by the support ring. The upper chords of the ribs form the outer surface of the dome, which is a surface of rotation. The upper ring under asymmetrical loads, in addition to compression, is subject to torsion, so its cross-section should be made rigid.
The degree of rigidity of the attachment of the ribs at the top of the dome depends on the design of this unit. If welding is used to connect the ribs, then the connection at the top of the ribs with the ring can be assumed to be rigid. The lower support ring is made in the form of a polygon, the number of sides of which corresponds to the number of ribs.
In the case of a circular design of the lower ring, local bending due to the curvature of the ring must be taken into account. The intermediate ring girders resting on the ribs have low rigidity or are not rigidly attached to the ribs, and therefore they do not have a significant effect on the deformation of the ribs.
The ribs of the dome can be through (in the form of light trusses) or solid section. Solid ribs are heavier and easier to manufacture, especially when using rolled beams. To ensure the overall rigidity of the dome, it is necessary to install tie panels in the plane of the ribs in at least two sectors, running from the top of the dome to its supports.
Ribbed ring domes. If we include ring girders in a ribbed dome, we obtain a spatial structure consisting of flat ribs installed in the radial direction and interconnected by a series of rings, together forming a rigid spatial system. Rings, in addition to the normal forces that arise during the operation of the dome, in general can act in the same way for local bending as purlins. A polygon is fit into the outlined curve of the dome, and ultimately a polyhedron is obtained.
A ribbed-ring dome is more rational and lighter than a ribbed dome, since all structural elements are included in the work. If the connection of the rings to the ribs is carried out rigidly, then this design is unchangeable. When the rings are hinged to the ribs, it is imperative to install rigid tie panels to ensure the stability of the dome.
Ribbed-ring domes with lattice connections. Domes with lattice connections are designed in the form of polyhedra inscribed in the surface of rotation and consisting of meridional ribs and rings, between which braces are located. The forces arising from external loads are partially absorbed by the connections, while reducing the forces in the ribs and rings, which contributes to the appearance numerous poorly functioning lattice elements with complex joints at the fracture points of the dome face.
At the bottom, the domes are terminated by a lower stretched support ring, which receives the expansion of the dome; From above, the dome is usually cut off horizontally and has an upper ring to which all the ribs are attached.
All ribbed-ring domes with lattice connections can be made according to two schemes:
1) the ribs are connected to each other in pairs by a lattice so that only rings without connections pass through one sector;
2) lattice connections are arranged continuous in all sectors; in this case, the dome structure approaches the mesh structure.
Mesh domes. If you increase the connectivity of the system in a ribbed-ring dome, you can get mesh domes with hinged connections at the nodes. In mesh domes, forces are distributed over all elements of the dome surface, and with a hinged connection, all rods work only on axial force.
Currently, mesh domes are widely used due to their lightness and beautiful pattern. Mesh dome systems are very diverse. They are usually composed of tubular and angle rods forming a continuous lattice. The main disadvantage of mesh domes is the large number of different elements, components and connections, which increases the complexity of their manufacture and installation.
IN recent years The development of mesh domes is in the direction of assembling them from identical mass-produced elements. Star-shaped domes, all faces of which are triangles, as well as geodesic systems of domes, the load-bearing elements of which are the edges of a polygon inscribed in a sphere, have been realized. The rods of mesh domes are mostly made of pipes; the nodes are made on stamped gussets, ball cores or pipes.
The supporting system of domes often includes enclosing structures consisting of stamped aluminum or steel sheets. Mesh domes are a spacer system. To absorb the thrust, a lower support ring is usually installed, which serves as the main element of the supporting structure of the dome. Mesh domes proposed by B. Fuller are widely used abroad. They consist of steel tubular triangles or hexagons mounted on a spherical surface. The covering of the domes is made of aluminum or steel stamped sheets or translucent materials.
The main advantage of these designs is the use of similar elements and filling the mesh with lightweight materials, including translucent ones. Installation of domes can be carried out without scaffolding, by growing them using jacks or pneumatic devices.
Plate domes. Based on the division of domes adopted for various design solutions, plate domes were developed, which are assembled from stamped plates. Applying various types cutting, it is possible to create a series of planar plate elements in the form of quadrangles, triangles, rhombuses or hexagons, from which domes can be assembled.
Low cost, speed of installation, light weight and reliability allow these designs to be used for large diameter domes. Plate domes have become widespread in the United States.
It should be especially noted that all of the listed steel domes are expansion systems, and to absorb the expansion, as a rule, a lower support ring is installed, which is the main load-bearing element of the structure. In some cases, in the presence of rocky or similar soils, the thrust can be transferred directly to the foundation structure.
The forces in ribbed and ribbed-ring domes with or without connections can be determined on electronic computers using various programs. Below is an example of calculating a ribbed-ring dome on a computer.
Mesh domes can be calculated as a shell according to the momentless membrane theory, using the formulas given in Table. 3. The momentless theory can be applied even to a shell which has considerable flexural strength, and the change in curvature caused by most loads is so small as to be of no practical importance. The momentless theory also has the advantage that it is suitable for any shape of the middle surface of a dome of positive curvature and for almost all continuous loads encountered in practice. A significant advantage of the momentless theory is the static definability of efforts.
To determine the forces in the dome rods, you can always select the rod on which the forces are collected from a certain “force” area. In addition to axial forces, the rods may experience, depending on the design of the coating, bending from local loads, which must be taken into account when selecting the section.
The support of the lower rings on the foundations must be carried out in such a way as to ensure free movement in the radial direction. To do this, for large diameter domes (more than 30 m), either roller supports should be installed, or the mobility of the ring should be ensured by placing graphite lubricant under it or gaskets made of a material with a low coefficient of friction, for example, naphthlene, which has high strength indicators and a coefficient of friction equal to 0.02.
The upper figure a, b, c shows various schemes of ribbed and ribbed-ring dome coverings, and the lower figure shows coverings of a mesh structure:
1) simplest scheme mesh structure of the covering consisting of meridional ribs, rings and cross connections between them in all trapezoidal sections (lower figure).
2) a mesh structure used in the construction of a dome with a diameter of 196 m over an indoor stadium in Houston and a diameter of 207 m over an indoor stadium in New Orleans (USA). In both cases, the dome consists of 12 main meridional arched ribs, united at the top by a central ring and rested at the lower ends against a supporting ring of five intermediate annular ribs and crossed secondary ribs parallel to the main ones, thus forming triangular cells; the sections of the ribs and rings have the same height (lower figure, b);
3) the mesh structure developed by TsNIIProekt-steelstructure for covering above the test center is an ellipsoid of rotation with a diameter of 234 m at the equator and 224 m at the bottom, and a height of 112 m. The dome is assembled from ribbed triangular panels with side dimensions of 9 m without scaffolding. The outer side of the panels is a prestressed membrane 1.5 mm thick, which serves as the roof of the building (lower figure, c).
Chapter 6
DOME STRUCTURES
6.1. General information
World construction experience shows that domes are one of the effective forms of spatial structures. They turn out to be the most rational when covering large spans. So, if flat structures with a span of up to 40 m can still compete with dome ones in terms of metal consumption, then with an increase in the span, the advantage of dome ones is obvious. The efficiency of these structures increases with increasing span and it is no coincidence that most roofs over 200 m are domed. The compositional possibilities of such structures are also great. They make it possible to cover multipurpose buildings and create beautiful examples of architectural creativity.
Dome structures have been known since ancient times. They were used in Mesopotamia, Syria, Iran, and Ancient Rome. The main material was stone. The first metal domes appeared at the end of the 19th century. The main credit for the development of these structures belongs to Feppel and Schwedler. In the 20th century, significant contributions to the development of dome structures were made by Lederer, Makovsky, Otto, Wright, Fuller, Tupolev M.S., Lipnitsky M.E. , Savelyev V.A. .
Domes are spacer systems that, as a rule, contain three main structural elements: a lower support contour, a shell, and an upper support contour (Fig. 6.1).
Let's consider the main typologies of metal domes:
- a) by design: ribbed, ribbed-ring, ribbed-ring with ties, mesh, plate;
- b) in shape (Fig. 6.2): spherical, elliptical, lancet, umbrella and other shapes;
Rice. 6.1. Structural diagram of the dome:
1
- upper support contour; 2
- shell; 3
- lower support contour
Rice. 6.2. Dome shapes:
A- plan of a spherical dome; b- cross section of a spherical dome; V- plan of the elliptical dome; G- cross section of an elliptical dome; d- pointed dome; e- plan of the umbrella dome; and- type of umbrella dome
- c) along the lifting boom (Fig. 6.3): lifting (high) domes, with a lifting boom of 1/2 ... 1/5 of the diameter and flat, with a lifting height of 1/5 of the diameter.
Ribbed domes (Fig. 6.4) consist of individual flat ribs placed in a radial direction. With straight ribs, pyramidal or conical domes are formed. The upper belts of the ribs make up the surface of the dome; at its apex they are adjacent to the upper ring. Sometimes, with a frequent arrangement of ribs or a device at the top of the lantern dome, the ring turns out to be of considerable size; then, in order to increase rigidity and stability, it is fastened with internal struts in at least two diametrical planes.
Ribbed domes are a spacer system. Raspor
Rice. 6.3. Geometric parameters of the dome:
D- diameter; f- lifting height
can be perceived by the structure of foundations, walls or a special support ring. The support ring is designed in plan to be curved around a circle or in the form of a polyhedron with rigid or hinged connections at the corners. With a sufficiently frequent arrangement of ribs, it is possible to construct a round ring. With sparsely spaced ribs, it is better to design the support ring polygonal to avoid bending and torsion. The most common is a rigid polygonal ring with supports in the corners that are mobile in the radial direction. Special floorings are usually laid between the ribs or a membrane covering is created. Membrane or panel coverings provide overall stability of the ribs in the plane of the covering, reducing the effective length of the ribs. It is possible to construct a roof along ring girders between the ribs.
Ribbed-ring domes (Fig. 6.5). The design and inclusion of ring girders in the design results in the creation of a ribbed-ring scheme. The latter can be used as dome tightening. In this case, the rings not only act on local bending from roof loads, but also perceive normal forces from the dome ribs, and in the case of a rigid connection of the rings with the ribs, also bending moments. However, due to the low rigidity of the rings and ribs in planes tangent to the surface of the dome, the influence of the rigidity of the nodes can be neglected and it can be assumed that the rings are hinged to the ribs.
Ribbed-ring domes with ties (Fig. 6.6) represent a further increase in the connectivity of the system, spatiality of work, by introducing braces between the ribs into the design.
Mesh domes are formed if in a ribbed-ring dome with connections the connectivity of the system is increased until the formation of cross connections in each cell of the dome; this is exactly the design that is represented by the Schwedler dome (Fig. 6.7), which is one of the first mesh domes.
Another definition of a mesh dome is possible, as a polyhedron inscribed in a spherical or other surface of rotation and consisting
from one or two layers of structural elements forming a triangular, diamond-shaped, trapezoidal, pentagonal and hexagonal mesh. Such domes are also called geodesic or crystalline in a number of literary sources. Mesh domes usually only have a bottom support ring.
The founders of geodetic and crystal systems are prof. M.S. Tupolev (Russia) and R.B. Fuller (USA). Mesh domes are the most economical in terms of material consumption due to the spatial operation of the frame and the uniform distribution of material over the surface of the shell.
Plate domes assembled from metal plates (panels) that have stamped stiffening ribs connected to each other along the contour by welding or node connections.
The invention is used in construction during the construction and reconstruction of domes made of brick and stone and allows not only to reduce the consumption of material and labor costs for the manufacture of formwork several times, but also to significantly reduce the labor intensity and duration of its installation and disassembly. The dome formwork is assembled from two diametrically located movable sectors, resting their lower ends on the dome support ring, and their upper ends on a stand installed along the vertical axis of the dome, equipped in the upper part with two support disks and two nuts supporting them. Bricks are laid simultaneously along both pre-calibrated sectors of the formwork until a diametrically located brick arch is formed, which has an X-shaped plan, after which the formwork is rotated relative to the support post by 90 o and a second diametrically located X-shaped brick arch is laid, then the formwork is rotated around the support post by 45 o and lay the third arch, and after the next turn of the formwork by 90 o, lay the last fourth arch of the dome and begin to completely dismantle the formwork and its supporting elements. 2 and 2 z.p. f-ly, 3 ill.
The invention relates to the field of construction and can be used in the construction, reconstruction and repair of domes made of brick and stone.
The closest technical solution to the proposed invention in its essence and the achieved result is a method of erecting a dome using classical technology, including installation of formwork, laying bricks in successive rows in the direction from the lower support ring to its key, dismantling the formwork (see N.I. Aistov, B.D. Vasiliev, V.F. Ivanov and others. History of construction equipment. -L.: Gosstroyizdat, 1962. p. 123).
A device for implementing this method is known, including a solid deck, circles and their supporting elements (see N.I. Aistov, B.D. Vasiliev, V.F. Ivanov, etc. History of construction equipment. - L.: Gosstroyizdat, 1962 , p.123).
The disadvantage of the known method and device for its implementation is the high consumption of materials and labor costs for the manufacture, installation and disassembly of the deck, circles and their supporting elements.
The purpose of the invention is to reduce the consumption of materials and labor costs for the manufacture, installation, and disassembly of formwork.
This goal is achieved by the fact that in the known method of erecting a dome, including installing formwork, laying bricks in successive rows in the direction from the dome's support ring to its key, dismantling the formwork, the dome formwork is assembled from two diametrically located mobile sectors, supporting them with their lower, wide ends on the support ring of the dome, and with the upper, narrow ends on a support post pre-installed along the vertical axis of the dome, bricks are laid simultaneously along both pre-calibrated sectors of the formwork until a diametrically located brick arch is formed, having an X-shape in plan, after which, rearranging formwork to the next position, rotate both of its sectors relative to the support post by 90 o, and lay the second diametrically located X-shaped brick arch, again rotate both sectors relative to the support post, and at an angle equal to 45 o, and lay the third arch and ligating its masonry with the edges of previously laid adjacent arches, after which both sectors are rotated relative to the support post by 90 o and laying the last fourth arch of the dome and ligating its masonry with the edges of previously laid adjacent arches.
The described method is carried out using a special device, and the goal is achieved by the fact that in the known device, including a deck, circles and their supporting elements, the dome deck is made in the form of two petals curved along the radius, having in plan the shape of two diametrically located circular sectors and the possibility move in a circle relative to the support post located along the vertical axis of the dome. At the same time upper part The rack is made with a screw thread and is equipped with two nuts mounted on it and two horizontally located disks, the center of which coincides with the longitudinal axis of the rack.
The use of the proposed method and device for its implementation during the construction of the dome allows, by reducing the formwork area by four times, to significantly reduce not only material and labor resources for its production, but also, by simplifying the technology, reduce the labor intensity and duration of installation and dismantling of the formwork, and also allows you to increase the turnover of the latter, since after the completion of the laying of the fourth sector arch, immediately without a technological break it allows you to begin unwinding and complete disassembly of the formwork and its supporting elements. This becomes possible, firstly, due to the fact that by the end of the laying of the dome it is already securely held due to the first two sector arches, and secondly, thanks to the constructive connection, for example, the ligation between the first arches and the third and fourth arches adjacent to them, which provides working together all sector arches of the dome.
In fig. 1 shows the device, general view, longitudinal section; in fig. 2 - view A in figure 1; in fig. Figure 3 shows the sequence of rearranging the formwork sectors and erecting sector arches.
The device for erecting a dome includes a formwork 1, which has a plan form of two diametrically located circular sectors, consisting, for example, of a deck 2 curved along the radius, circular trusses 3 and having the ability to rotate around a support post 4, located along the vertical axis of the dome and braced with guy wires 5 The upper part of the support post 4 is made with a screw thread (not shown) and is equipped with two support nuts 6, 7 mounted on it and two horizontally located disks 8 and 9, the center of which coincides with the longitudinal axis of the post 4. In this case, the upper disc. 8 is attached motionlessly during the construction of the dome, for example, using a stopper (not shown), and is a temporary support for a key, for example, a brick sector arch, which has an X-shape in plan. The lower disk 9 is installed with the possibility of rotation around the longitudinal axis of the rack 4 and is a support for the upper, narrow, ends of the sectors of the formwork 1, which with its lower, wide ends rests through paired horizontal wedges 10 on the support ring 11 of the dome.
The method of erecting a dome using the proposed device is carried out as follows. First, along the vertical axis of the dome, a support post 4 is installed and secured with braces 5 with disks 8 and 9 installed on it at the required height, resting on nuts 6 and 7, respectively. Then two sectors of the formwork 1 are installed with the possibility of subsequent movement, positioning them diametrically opposite to the support pillars 4 and resting the lower, wide end on the support ring of the dome 11, and the upper, narrow end on the lower disk 9, which has the ability to rotate around the longitudinal axis of the support post 4. After appropriate alignment of the position of the formwork, they begin the direct construction of the dome, laying, for example, bricks in successive rows simultaneously along both sectors of the formwork 1, starting from the support ring 11 towards the fixed disk 8 until the formation of a diametrically located brick sector arch, which has an X-shape in plan. Then, using the nut 7 and paired horizontal wedges 10, the formwork 1 is turned around and moved to the next position, turning both of its sectors relative to the vertical axis of the support post 4 by 90 o. After the next verification of the position of the formwork sectors, the second diametrically located X-shaped brick arch is laid. The formwork is turned around again, both of its sectors are rotated around the support post by 45 o, its installation is verified in a new position and the third diametrically located arch of the dome is laid, ensuring that its masonry is tied to the edges of the previously laid adjacent arches. After which, repeating the above operations, both sectors are rotated around the support post 4 by 90 o and, after their alignment, they begin laying the last fourth arch of the dome, ensuring that its masonry is tied with the edges of the previously laid adjacent arches, and, if necessary, after laying In the fourth arch of the dome, the last brick is immediately untwisted and its formwork and its supporting elements are completely dismantled. The construction of a dome using the proposed method, if necessary under certain conditions, can be carried out by laying bricks in a larger number of sector arches.
If necessary, small block stones are used to lay the dome.
This method makes it possible to reduce the material consumption of formwork several times, reduce the labor intensity and duration of its installation and disassembly, and also increase its turnover.
1. A method for erecting a dome, including installing formwork, laying bricks in successive rows in the direction from the dome’s support ring to its key, developing formwork, characterized in that the dome’s formwork is assembled from two diametrically located movable sectors, resting their lower, wide ends on the support ring of the dome, and with the upper, narrow ends on a support post pre-installed along the vertical axis of the dome, bricks are laid simultaneously along both pre-calibrated sectors of the formwork until a diametrically located brick arch is formed, having an X-shape in plan, after which, rearranging the formwork to next position, turn both of its sectors relative to the support post by 90 o and lay the second diametrically located X-shaped brick arch, again turn both sectors relative to the support post, and at an angle of 45 o, and lay the third arch and bandage its masonry with the edges previously laid adjacent arches, after which both sectors are rotated relative to the support post by 90 o and the last fourth arch of the dome is laid and its masonry is tied to the edges of the previously laid adjacent arches.
2. The method according to claim 1, characterized in that after laying the last brick in the fourth arch, the formwork and its supporting elements are immediately untwisted and completely dismantled.
3. The method according to claim 1, characterized in that small block stones are used for laying the dome.
4. A device for erecting a dome, including a deck, circles and their supporting elements, characterized in that the dome deck is made in the form of two radially curved petals, having in plan the shape of two diametrically located circular sectors and the ability to move in a circle relative to the support post located along the vertical axis of the dome, while the upper part of the rack is made with a screw thread and is equipped with two nuts and two horizontally located disks mounted on it with the possibility of movement, the center of which coincides with the longitudinal axis of the rack.