Modern long-span buildings and structures. Long-span roofing structures for civil and industrial buildings. Walls made of large panels

Planar structures

A

LECTURE 7. STRUCTURAL SYSTEMS AND STRUCTURAL ELEMENTS OF INDUSTRIAL BUILDINGS

Frames industrial buildings

Steel frame of one-story buildings

The steel frame of one-story buildings consists of the same elements as reinforced concrete (Fig.)

Rice. Steel frame building

There are two main parts in steel columns: the rod (branch) and the base (shoe) (Fig. 73).

Rice. 73. Steel columns.

A– constant cross-section with console; b– separate type.

1 – crane part of the column; 2 – supracolumn, 3 – additional height of the supracolumn; 4 – tent branch; 5 – crane branch; 6 – shoe; 7 – crane beam; 8 – crane rail; 9 – covering truss.

Shoes serve to transfer the load from the column to the foundation. Shoes and lower parts of columns in contact with the ground are concreted to prevent corrosion. To support the walls, prefabricated reinforced concrete foundation beams are installed between the foundations of the outer columns.

Steel crane beams can be solid or lattice. The most widely used are solid crane beams having an I-section: asymmetrical, used with a column spacing of 6 meters, or symmetrical with a column spacing of 12 meters.

The main load-bearing structures of coatings in buildings with steel frame are roof trusses(Fig. 74).

Rice. 74. Steel trusses:

A– with parallel belts; b- Same; V– triangular; G– polygonal;

d – polygonal truss design.

In outline they can be with parallel belts, triangular, polygonal.

Trusses with parallel belts are used in buildings with flat roofs, and also as rafters.

Triangular trusses are used in buildings with roofs that require large slopes, for example, made of asbestos-cement sheets.

The rigidity of the steel frame and its perception of wind loads and inertial influences from cranes is ensured by the arrangement of connections. Between the columns in longitudinal rows, vertical connections are placed - cross or portal. Horizontal transverse ties are placed in the planes of the upper and lower chords, and vertical ones - along the axes of the support posts and in one or more planes in the middle of the span.

Expansion joints

IN frame buildings expansion joints divide the building frame and all structures resting on it into separate sections. There are transverse and longitudinal seams.

Transverse expansion joints are installed on paired columns that support the structures of adjacent sections of the building cut by the joint. If the seam is also sedimentary, then it is also installed in the foundations of paired columns.

In one-story buildings, the axis of the transverse expansion joint is combined with the transverse alignment axis of the row. Expansion joints in the floors of multi-story buildings are also solved.

Longitudinal expansion joints in buildings with a reinforced concrete frame are made on two longitudinal rows of columns, and in buildings with a steel frame - on one row of columns.

Walls of industrial buildings

In buildings without frames or with an incomplete frame, the outer walls are load-bearing and are made of brick, large blocks or other stones. In buildings with a full frame, the walls are made of the same materials, self-supporting on foundation beams or panel - self-supporting or hinged. External walls are located with outside columns, the internal walls of buildings rest on foundation beams or strip foundations.

In frame buildings with a significant length and height of the walls, to ensure stability between the elements of the main frame, additional racks are introduced, sometimes crossbars, forming an auxiliary frame called half-timbered.

For external drainage from coatings, the longitudinal walls of industrial buildings are made with cornices, and the end walls are made with parapet walls. With internal drainage, parapets are erected along the entire perimeter of the building.

Walls made of large panels

Reinforced concrete ribbed panels are intended for unheated buildings and buildings with large industrial heat releases. Wall thickness 30 millimeters.

Panels for heated buildings are made from insulated reinforced concrete or lightweight cellular concrete. Reinforced concrete insulated panels have a thickness of 280 and 300 millimeters.

The panels are divided into ordinary (for blank walls), lintel panels (for installation above and below window openings) and parapet panels.

In Fig. 79 shows a fragment of a wall of a frame panel building with strip glazing.

Rice. 79. Fragment of a wall made of large panels

The filling of window openings in panel buildings is carried out mainly in the form of strip glazing. The height of the openings is taken to be a multiple of 1.2 meters, the width is equal to the pitch of the wall columns.

For individual window openings of smaller width, wall panels with dimensions of 0.75, 1.5, 3.0 meters are used in accordance with the dimensions of standard frames.

Windows, doors, gates, lanterns

Lanterns

To provide lighting for workplaces located far from windows and for aeration (ventilation) of premises, lanterns are installed in industrial buildings.

Lanterns come in light, aeration and mixed types:

Lights with solid glazed frames, serving only to illuminate rooms;

Light-aeration with opening glazed doors, used for lighting and ventilation of rooms;

Aeration without glazing, used only for aeration purposes.

Lanterns can be of various profiles with vertical, inclined or horizontal glazing.

The profile of the lanterns is rectangular with vertical glazing, trapezoidal and triangular with inclined glazing, jagged with one-sided vertical glazing. In industrial construction, rectangular lanterns are usually used. (Fig. 83).

Rice. 83. Basic schemes of light and light-aeration lanterns:

A– rectangular; b– trapezoidal; V– toothed; G– triangular.

Based on their location relative to the axis of the building, lanterns are distinguished between longitudinal and transverse. Longitudinal lights are the most widespread.

Water drainage from lanterns can be external or internal. External is used for lanterns 6 meters wide or when there is no internal drainage system in the building.

The design of the lanterns is framed and consists of a number of transverse frames resting on the upper chords of trusses or roof beams, and a system of longitudinal bracings. The design diagrams of the lamps and their parameters are unified. For spans of 12, 15, and 18 meters, lanterns with a width of 6 meters are used, for spans of 24, 30 and 36 meters - 12 meters wide. The lantern fence consists of a covering, side and end walls.

Lantern covers are made of steel with a length of 6000 millimeters and a height of 1250, 1500 and 1750 millimeters. The bindings are glazed with reinforced or window glass.

Aeration is called natural, controlled and regulated air exchange.

The action of aeration is based on:

On thermal pressure arising due to the difference in temperature between indoor and outdoor air;

At the height difference (difference between the centers of the exhaust and supply openings);

Due to the action of the wind, which blows around the building, it creates a rarefaction of air on the leeward side (Fig. 84).

Rice. 84. Building aeration schemes:

A– the effect of aeration in the absence of wind; b- the same with the action of wind.

The disadvantage of light-aeration lanterns is the need to close the covers on the windward side, since the wind can blow polluted air back into the work area.

Doors and gates

Doors of industrial buildings do not differ in design from panel doors of civil buildings.

Gates are intended for entry into the building Vehicle and the passage of large masses of people.

The dimensions of the gate are determined in accordance with the dimensions of the equipment being transported. They must exceed the dimensions of the loaded rolling stock in width by 0.5-1.0 meters, and in height by 0.2-0.5 meters.

According to the method of opening, gates can be swing, sliding, lifting, curtain, etc.

Swing gates consist of two panels hung by means of loops in the gate frame (Fig. 81). The frame can be wooden, steel or reinforced concrete.

Rice. 81. Swing gates:

1 – pillars of the reinforced concrete frame framing the opening; 2 – crossbar.

If there is no space for opening the doors, the gates are made sliding. Sliding gates There are single-field and double-field. Their door leaves have a design similar to swing doors, but in the upper part they are equipped with steel rollers, which, when opening and closing the gate, move along a rail attached to the crossbar of the reinforced concrete frame.

The lifting gate leaves are all-metal, suspended on cables and move along vertical guides.

The panel of curtain doors consists of horizontal elements that form a steel curtain, which, when lifted, is screwed onto a rotating drum located horizontally above the top of the opening.

Coatings

In one-story industrial buildings, the coverings are made without an attic, consisting of the main load-bearing elements of the covering and fencing.

In unheated buildings and buildings with excessive industrial heat generation, the enclosing structures of the coatings are made uninsulated, in heated buildings - insulated.

The cold roof structure consists of a base (flooring) and a roof. The insulated coating includes a vapor barrier and insulation.

Flooring elements are divided into small-sized (1.5 - 3.0 meters long) and large-sized (6 and 12 meters long).

In fencing made of small-sized elements, it becomes necessary to use purlins, which are placed along the building along beams or covering trusses.

Large-sized floorings are laid along the main load-bearing elements and the coatings in this case are called non-run.

Floorings

Non-running reinforced concrete decks are made of prestressed reinforced concrete ribbed slabs 1.5 and 3.0 meters wide and a length equal to the pitch of beams or trusses.

In non-insulated coverings, a cement strainer, on which the roll roofing is glued.

In insulated coatings, low-thermal conductivity materials are used as insulation and additional vapor barrier is installed. Vapor barrier is especially necessary in coverings above rooms with high humidity air.

Small-size slabs can be reinforced concrete, reinforced cement or reinforced lightweight and cellular concrete.

Roll roofs are made of roofing material. The top layer of roll roofing is installed protective layer gravel embedded in bitumen mastic.

Flooring made from leafy materials.

One of these floorings is galvanized steel profiled flooring, laid on purlins (with a truss spacing of 6 meters) or along lattice purlins (with a spacing of 12 meters).

Pitched cold coverings are often made from asbestos-cement corrugated sheets reinforced profile 8 mm thick.

In addition, sheets of corrugated fiberglass and other synthetic materials are used.

Drainage from coatings

Drainage extends the life of a building, protecting it from premature aging and destruction.

Drainage from the coatings of industrial buildings can be external and internal.

In one-story buildings, external drainage is arranged unorganized, and in multi-story buildings - with the use of drainpipes.

The internal drainage system consists of water intake funnels and a network of pipes located inside the building that drain water into storm sewer(Fig. 82).

Rice. 82. Internal drainage:

A– water intake funnel; b– cast iron pan;

1 – funnel body; 2 – cover; 3 – pipe; 4 – pipe collar; 5 – cast iron pan; 6 – hole for the pipe; 7 – burlap impregnated with bitumen; 8 - roll roofing; 9 – filling with molten bitumen; 10 – reinforced concrete covering slab.

Internal drainage is arranged:

In multi-span buildings with multi-pitched roofs;

In buildings with large heights or significant differences in height of individual spans;

in buildings with large industrial heat releases, causing snow to melt on the surface.

Floors

Floors in industrial buildings are selected taking into account the nature of production impacts on them and the operational requirements placed on them.

Such requirements may be: heat resistance, chemical resistance, water and gas impermeability, dielectricity, non-sparking upon impact, increased mechanical strength and others.

It is sometimes impossible to select floors that meet all the necessary requirements. In such cases, it is necessary to use different types of floors within the same room.

The floor structure consists of a covering (clothing) and an underlying layer (preparation). In addition, the floor structure may include layers for various purposes. The underlying layer absorbs the load transmitted to the floors through the coating and distributes it to the base.

The underlying layers are rigid (concrete, reinforced concrete, asphalt concrete) and non-rigid (sand, gravel, crushed stone).

When installing floors on interfloor floors, floor slabs serve as the base, and the underlying layer is either absent altogether, or its role is played by heat and sound insulating layers.

Ground floors used in warehouses and hot shops, where they may be subject to shock from falling heavy objects or come into contact with hot parts.

Stone floors used in warehouses where significant shock loads are possible, or in areas covered by tracked vehicles. These floors are durable, but cold and hard. Such floors are usually covered with paving stones (Fig. 85).

Rice. 85. Stone floors:

A– cobblestones; b– from large paving stones; V– from small paving stones;

1 – cobblestone; 2 – sand; 3 – paving stones; 4 – bitumen mastic; 5 – concrete.

Concrete and cement floors used in rooms where the floor may be subject to constant moisture or exposure mineral oils(Fig. 86).

Rice. 86. Concrete and cement floors:

1 – concrete or cement clothing; 2 – concrete underlying layer.

Asphalt and asphalt concrete floors have sufficient strength, water resistance, water resistance, elasticity, and are easy to repair (Fig. 87). The disadvantages of asphalt floors include their ability to soften when the temperature rises, as a result of which they are not suitable for hot workshops. Under the influence of prolonged concentrated loads, dents form in them.

Rice. 87. Asphalt and asphalt concrete floors:

1 – asphalt or asphalt concrete clothing; 2 – concrete underlying layer.

TO ceramic floors include clinker, brick and tile floors (Fig. 88). Such floors are highly resistant to high temperatures and are resistant to acids, alkalis and mineral oils. They are used in rooms that require great cleanliness, in the absence of shock loads.

Rice. 88. Ceramic tile floors:

1 – ceramic tile; 2 – cement mortar; 3 – concrete.

Metal floors used only in certain areas where the floors are touched by hot objects and at the same time a flat, hard surface is needed and in workshops with strong shock loads (Fig. 89).

Rice. 89. Metal floors:

1 – cast iron tiles; 2 – sand; 3 – soil base.

Floors can also be used in industrial buildings planks and from synthetic materials. Such floors are used in laboratories, engineering buildings, and administrative premises.

In floors with a rigid underlying layer, expansion joints are installed to avoid cracks. They are arranged along the lines expansion joints buildings and in places where different types of floors meet.

To lay utility lines, channels are installed in the floors.

The junction of floors to walls, columns and machine foundations is made with gaps for free settlement.

In wet rooms, to drain liquids, the floors are given a relief with slopes towards cast iron or concrete water intakes, which are called ladders. The drains are connected to the sewerage system. Along the walls and columns it is necessary to install skirting boards and fillets.

Stairs

Stairs of industrial buildings are divided into the following types:

- basic, used in multi-storey buildings for permanent communication between floors and for evacuation;

- official, leading to work sites and mezzanines;

- fire extinguishers, mandatory for building heights of more than 10 meters and intended for fire brigade members to climb onto the roof (Fig. 90).

Rice. 90. Fire escape

- emergency external, arranged for the evacuation of people when there is an insufficient number of main stairs (Fig. 91);

Rice. 91. Emergency ladder

Fire barriers

Classification of buildings and premises according to explosion and fire hazard is used to establish requirements fire safety aimed at preventing the possibility of fire and ensuring fire protection people and property in case of fire. According to explosion and fire hazard, premises are divided into categories A, B, B1-B4, D and D, and buildings into categories A, B, C, D and D.

Categories of premises and buildings are determined based on the type of flammable substances and materials located in the premises, their quantity and fire hazardous properties, as well as based on the space-planning solutions of the premises and the characteristics of the technological processes carried out in them.

Fire barriers are installed to prevent fire from spreading throughout the building in the event of a fire. Fireproof floors serve as horizontal barriers in multi-storey buildings. Vertical barriers are fire walls (firewalls).

Firewall is intended to prevent the spread of fire from one room or building to an adjacent room or building. Firewalls are made of fireproof materials - stone, concrete or reinforced concrete, and must have a fire resistance rating of at least four hours. Firewalls must rest on foundations. Firewalls are made to cover the entire height of the building, separating combustible and non-combustible coverings, ceilings, lanterns and other structures and must rise above combustible roofs by at least 60 centimeters, and above non-combustible roofs by 30 centimeters. Doors, gates, windows, manhole covers and other fillings of openings in firewalls must be fireproof with a fire resistance rating of at least 1.5 hours. Firewalls are designed for stability in the event of a one-sided collapse of floors, coverings and other structures during a fire (Fig. 92).

Rice. 92. Firewalls:

A– in a building with fireproof external walls; b– in a building with combustible or non-combustible external walls; 1 – firewall ridge; 2 – end firewall.

Control questions

1. Name the design diagrams of industrial buildings.

2. Name the main types of frames for industrial buildings.

3. What types of walls are there in industrial buildings?

LECTURE 8. STRUCTURAL SYSTEMS AND STRUCTURAL ELEMENTS OF AGRICULTURAL BUILDINGS AND STRUCTURES

Greenhouses and greenhouses

Greenhouses and hotbeds are glazed structures in which the necessary climatic and soil conditions are artificially created to allow the cultivation of early vegetables, seedlings and flowers.

Greenhouse buildings are constructed primarily from prefabricated reinforced concrete glazed panels, fastened together by welding embedded parts.

The greenhouse structure consists of prefabricated reinforced concrete frames installed in the ground along the length of the greenhouse and prefabricated reinforced concrete frames (longitudinal bed of the greenhouse) laid on the frame consoles. Removable glazed greenhouse frames are made of wood (Fig. 94).

Rice. 94. Greenhouse made of prefabricated reinforced concrete elements:

1 – reinforced concrete frames; 2 – reinforced concrete northern log; 3 – the same, southern;

4 – sand; 5 – nutrient layer of soil; 6 – heating pipes in a layer of sand;

7 – glazed wooden frame.

LIST OF REFERENCES USED

1. Maklakova T. G., Nanasova S. M. Constructions of civil buildings: Textbook. – M.: ASV Publishing House, 2010. – 296 p.

2. Budasov B.V., Georgievsky O. V., Kaminsky V. P. Construction drawing. Textbook for universities / Under general. ed. O. V. Georgievsky. – M.: Stroyizdat, 2002. – 456 p.

3. Lomakin V. A. Fundamentals of construction. – M.: Higher School, 1976. – 285 p.

4. Krasensky V.E., Fedorovsky L.E. Civil, industrial and agricultural buildings. – M.: Stroyizdat, 1972, – 367 p.

5. Koroev Yu. I Drawing for builders: Textbook. for prof. Textbook establishments. – 6th ed., erased. – M.: Higher. school, ed. Center "Academy", 2000 – 256 p.

6. Chicherin I. I. Civil works: a textbook for beginners. prof. Education. – 6th ed., erased. – M.: Publishing Center “Academy”, 2008. – 416 p.

LECTURE 6. STRUCTURES OF LONG-SPAN BUILDINGS WITH SPATIAL COVERINGS

Depending on the design and static operation bearing structures coatings can be divided into planar (working in one plane) and spatial.

Planar structures

This group of load-bearing structures includes beams, trusses, frames and arches. They can be made of prefabricated and monolithic reinforced concrete, as well as metal or wood.

Beams and trusses together with columns form a system of transverse frames, the longitudinal connection between which is carried out by covering slabs and wind braces.

Along with prefabricated frames, in a number of unique buildings with increased loads and large spans, monolithic reinforced concrete or metal frames are used (Fig. 48).

Rice. 48. Long span structures:

A- monolithic reinforced concrete frame, double-hinged.

To cover spans over 40 meters, it is advisable to use arched structures. Arches can be structurally divided into two-hinged (with hinges on the supports), three-hinged (with hinges on the supports and in the middle of the span) and hingeless.

The arch works mainly in compression and transfers not only vertical load, but also horizontal pressure (thrust) to the supports.

Compared to beams, trusses and frames, arches have less weight and are more economical in terms of material consumption. Arches are used in structures in combination with vaults and shells.

LECTURE NOTES

Makeevka 2011

MINISTRY OF EDUCATION AND SCIENCE, YOUTH AND SPORTS OF UKRAINE

DONBASS NATIONAL ACADEMY OF CONSTRUCTION AND ARCHITECTURE

Department of “Enterprise Economics”

Developed by: Ph.D., Associate Professor. Zakharchenko D.A.

LECTURE NOTES

in the course "Fundamentals of the construction industry"

for students of specialty 6.030504 “Enterprise Economics”

Code No. _______

Approved at a department meeting

"Enterprise Economics"

PROTOCOL No. __ dated _______2011

Makeevka 2011

TOPIC 4. LONG-SPAN BUILDINGS AND STRUCTURES

Long-span structures include those that have spans of more than 40-80 m. Relatively recently, such structures were considered unique and were built extremely rarely; currently, the rapid development of science and technology, as well as the great need for such structures in industry and the sphere of leisure and entertainment, have predetermined intensive construction of such structures in many countries.

Of particular interest are spatial structures that do not consist of separate, independent load-bearing elements that transfer each other’s load, but represent a single complex system working parts of the structure.

This spatial nature of structures, widely introduced into construction throughout the world, is a symbol of 20th century construction technology. And although some types of spatial structures - domes, crosses and vaults - have been known since ancient times, they do not correspond either to the applicability of materials or to design solutions modern requirements construction, since although they covered significant spans, they were extremely heavy and massive.

What is attractive about spatial designs is their ability to optimally satisfy the functional and aesthetic requirements of architecture. The scale of overlapped spans, the ability to implement flexible planning, diversity geometric shapes, materials, architectural expressiveness - this is far from full list features of these structures.

The combination of functional, technical and artistic-aesthetic provides spatial structures with a broad perspective, not to mention the fact that their use allows for huge savings in building materials - reducing the material consumption of buildings and structures by 20-30%.

Planar long-span structures include beams, frames, trusses, and arches. Planar structures operate autonomously under load, each in its own plane. The load-bearing element of planar structures covering some area of ​​the building (slab, beam, truss) works independently and does not participate in the work of the elements to which it is adjacent. This causes lower spatial rigidity and load-bearing capacity of planar elements compared to spatial ones, as well as their higher resource consumption, primarily increased consumption of materials.

Rice. 4.1. Design solutions for long-span structures

a - flat structures; b - spatial structures; c - hanging structures; g - pneumatic structures; 1- farms; 2 - frames; 3-4 articulated arches; 5- cylindrical shells; 6- shells of double curvature; 7- domes; 8- structures; 9- cable-stayed structures; 10-membrane structures; 11- awning structures; 12- pneumatic support structures; 13- pneumatic frame structures;

The frames of a solid structure are installed using two self-propelled jib cranes. First, frame racks with a part of the crossbar are installed on the foundation, resting on a temporary support, and then the middle section of the crossbar is mounted. The parts of the crossbar are connected on temporary supports by welding or strong welding. After installing the first frame, the structure is braced using guy wires.

In some cases, it is advisable to install frame structures using the sliding method. This method is used if frame structures cannot be immediately installed in the design position (work is underway inside or structures have already been erected that do not allow the placement of cranes).

The block is assembled at the end of the building in a special conductor of 2-3 or 4 trusses. The assembled and secured block is lifted along the rail tracks to the design position. Install using jacks or light cranes.

Arched structures are of 2 types: in the form of a 2-hinged arch with a tightening and a 3-hinged arch. When installing arched structures with a load-bearing part in the form of a double-hinged arch, it is carried out similarly to the installation of frame structures using self-propelled jib cranes. The main requirement is high installation accuracy, guaranteeing alignment of the fifth (support) hinge with the support.

The installation of three-hinged arches differs in some features related to the presence of an upper hinge. The latter is assembled using a temporary mounting support installed in the middle of the span. Installation is carried out using the vertical lifting method, sliding or turning methods.

Rice. 4.3. Frame installation

a - installation entirely by two cranes; b - installation of frames in parts using temporary supports; c - installation of frames using the rotation method; 1-installation crane; 2-frame assembly; 3-piece frame; 4-temporary supports; 5 winches; 6-mount booms.

Each semi-arch is slung at the center of gravity and installed so that the heel hinge is placed on a support, and the second end is placed on a temporary support. The same with the other half-arch. Rotation in the heel hinge is achieved by aligning the axes of the locking holes of the upper hinge.

In spatial structures, all elements are interconnected and participate in the work. This leads to a significant reduction in metal consumption per unit area. However, until recently, such spatial systems (dome, cable-stayed, structural, shells) were not developed due to the high complexity of manufacturing and installation.

Rice. 4.4. Mounting the Dome Using a Temporary Center Support

A - dome cutting system; B - installation of the dome; 1-temporary support with guy wires; 2-radial panels; 3-support ring;

Dome systems are mounted from individual rods or individual plates. Depending on the design solution, installation of dome structures can be carried out using a temporary stationary support, in a hinged way or in its entirety.

Spherical domes are erected in ring tiers using a hanging method. Each such tier has after complete assembly statistical stability and bearing capacity and serves as the basis for the overlying tier. Prefabricated domes can be mounted using conductor devices and temporary fastenings - a circus dome in Kyiv, or the dome is assembled entirely on the ground and then lifted to the design horizon by crane, pneumatic transport or lift. The method of growing from below is used.

Hanging structures began to be used from the 2nd half of the 19th century. And one of the first examples is the covering of the pavilion of the All-Russian Nizhny Novgorod Fair, completed in 1896. the outstanding Soviet engineer Shukhov.

The experience of using such systems has proven their progressiveness, since they make it possible to make maximum use of high-strength steels and lightweight enclosing structures made of plastics and aluminum alloys, which makes it possible to create coverings of significant spans.

Rice. 4.5. Installation of hanging structures

1-tower crane; 2-traverse; 3-cable half-truss; 4-central drum; 5-temporal support; 6-mounted semi-truss; 7 - support ring.

IN Lately Frame hanging structures have become widespread. The peculiarity of the construction of suspended structures is that first, load-bearing supports are erected, on which a support contour is laid, which absorbs the tension from the cable strands. After they are completely laid out, the coating is loaded with a temporary load taking into account the full design load. This method of prestressing prevents the appearance of cracks in the shell after its full load during operation.

A type of suspended cable-stayed structures are membrane coverings. The membrane covering is a hanging system in the form of a thin metal sheet structure stretched over a reinforced concrete support contour. One end of the roll is fixed to the support contour, and the roll is unwound to its entire length using a special traverse by a crane, pulled by winches and secured to the opposite section of the support contour.

The disadvantage of membrane coatings is the need to weld thin sheets along the length and mounting elements together with an overlap of 50 mm. At the same time, it is almost impossible to obtain a seam of equal strength with the base metal by welding, so the thickness of the sheet is artificially increased. This problem is solved to some extent by a system of interlocking tapes made of aluminum alloys.

The first long cylindrical shells were first used in 1928. in Kharkov during the construction of a post office.

Long cylindrical shells are supplied fully finished or enlarged on site. The weight of 3x12 mounting elements is about 4 tons. Before lifting, two plates are enlarged in a mobile jig together with tightening into one element. When enlarging, the embedded parts are welded at the joint, the tightening is tightened and the seams are sealed.

Having installed 8 enlarged sections forming a span of 24 m, they are aligned so that the holes coincide, then all the embedded parts and outlets of the longitudinal reinforcement are welded, the reinforcement is tensioned and the joints are concreted. After the concrete has cured, the shell is turned around and the scaffolding is rearranged.

In construction practice, spatial, cross, ribbed and bar structures are usually combined under the name structural structures.

Cross systems of structural coatings of various shapes with rectangular and diagonal gratings have become widespread relatively recently since the second half of the 20th century in countries such as the USA, Germany, Canada, England, and the former USSR.

For some time, structural structures were not widely developed due to the high labor intensity of manufacturing and the peculiarities of installation of the structure. Improvement of the design, especially with the use of computers, made it possible to ensure the transition to their in-line production, reduce the complexity of their calculations, increase its accuracy and, therefore, reliability.

Fig.4.6. Covering a building from large-size slabs

1-slab measuring 3x24m; 2-anti-aircraft lamp; 3-rafter truss; 4- column.

Cross-bar systems are based on a supporting geometric shape. Distinctive feature of different types of structural structures - the spatial junction of the rods, which largely determines the complexity of manufacturing and assembling these structures.

Structural structures have a number of advantages compared to traditional planar solutions in the form of frames and beam structures:

• are collapsible and can be used repeatedly;
• can be manufactured on automated production lines, which is facilitated by high typification and unification structural elements(often one type of rod and one type of node are required);
• assembly does not require high qualifications;
• They have compact packaging and are convenient for transportation.

Along with the noted advantages, structural structures also have a number of disadvantages:

• large-scale assembly requires the use of a significant amount of manual labor;
• limited load-bearing capacity of certain types of structures;
• low factory readiness of structures received for installation.

Pneumatic structures are used for temporary shelter or for use for some auxiliary purposes, for example as supporting structures during the construction of shells and other spatial structures.

Pneumatic coverings can be of 2 types - air-supporting and air-carrying. In the first case, a slight excess pressure of the soft shell of the structure ensures that the required shape is obtained. And this shape will be maintained as long as the air supply and the necessary excess pressure are maintained.

In the second case, the load-bearing structure is made of air-filled pipes made of elastic material, forming a kind of frame of the structure. They are sometimes called high-pressure pneumatic structures because the air pressure in the pipes is much higher than that under the air support film.

The construction of air-supporting structures begins with preparing the site on which concrete or asphalt is laid. A foundation with anchoring and compacting devices is installed along the contour of the structure. Under the influence of air pressure, the shell straightens and takes on the designed shape.

Air-carrying or pneumatic frame structures are constructed similarly to air-supported ones, with the only difference being that the air is supplied from the compressor through rubber pipes and through special valves is pumped into the closed channels of the so-called structure frame. Thanks to high blood pressure in the chambers, the frame takes the design position (most often in the form of arches) and lifts the enclosing fabric behind it.

Architectural appearance long-span buildings is largely determined by their role in the composition of a fragment of the surrounding urban development, the functional features of buildings and the applied coating structures.

The public functions of hall-type buildings require the allocation of significant free spaces in front of them for various purposes for: moving large flows of spectators before or after the start of shows (in front of entertainment or demonstration sports facilities); placement of the open part of the exhibition (in front of exhibition pavilions): seasonal trade (in front of covered markets), etc. In front of any of these buildings, areas are also allocated for parking individual cars. Thus, regardless of the purpose of the building, its placement in the building makes it possible to holistically perceive the volume of the structure from distant points of view. This circumstance determines the general compositional requirements for the architecture of buildings: the integrity and monumentality of their appearance and the predominantly large scale of the main divisions of the volume.

This feature of the urban planning role public buildings hall type are often taken into account in the composition of their appearance. Auxiliary and service premises, which can be located in separate volumes attached to the main one (as, for example, in the Yubileiny Sports Palace in St. Petersburg), for the most part are not blocked, but fit into the main volume of the building. For this purpose, auxiliary and service premises of sports buildings are located in the lower floors or in the space under the stands, in buildings of covered markets and exhibition pavilions - in the ground and basement floors, etc.

Typical examples of the implementation of such a space-planning principle of building layout are such apparently different objects as the universal Olympic Hall “Friendship” in Luzhniki in Moscow and the building of the Takamatsu Prefecture Sports Center in Niigata (Japan).

The Druzhba Hall has a main showroom with a capacity of 1.5-4 thousand spectators (if transformed) with an arena of 42X42 m, designed for 12 sports with optimal visibility of all competitions (maximum distance 68 m). The hall is covered with a flat spherical shell supported on 28 inclined supports made of prefabricated monolithic folded shells of double curvature. The inclined arrangement of the supports made it possible to increase the dimensions of the first floor and thereby accommodate four training rooms and four sports grounds, inscribed in a single centrally symmetrical volume with a pronounced tectonic architectural form ( ).

Both examples show the influence of the structural form of the pavement on the architectural form. And this is no coincidence, since the coating structure makes up from 60 to 100% of the external fencing of buildings.

Among the functional parameters, the choice of the form of the coating is most influenced by the adopted plan, capacity, the nature of the placement of spectator seats (in sports and entertainment buildings) and the size of the spans of the coatings ( ). In world practice, a limited number of plan shapes are used for exhibition, multifunctional auditoriums and sports halls: rectangle, trapezoid, oval, circle, polygon.

However, the shape of the hall plan and the size of its spans do not uniquely determine the shape of the covering. Big influence Her choice is influenced not only by the plan, but also by the shape of the building determined by the functional features. As is known, in demonstration sports halls the capacity and location of the stands determine the asymmetrical or centrally symmetrical composition of the building, with which the choice of the shape of the covering must be coordinated. Hanging roofs harmonize well with the asymmetrical shape of the building, and both vaulted and hanging roofs harmonize well with the axisymmetric shape. For buildings centric in plan, centric roofing structures are applicable ( , ).

The final choice of coating form, in addition to functional ones, is determined by structural, technological, technical, economic, architectural and artistic requirements. According to the latter, the design of the unique long-span building should contribute to the creation of an expressive tectonic, individual, large-scale architectural form. The introduction of spatial suspended structures and rigid shell structures has provided unprecedented and multi-variant architectural possibilities. By combining different types, numbers, and sizes of elementary shells, the architect, with the help of a designer, can achieve the required large-scale division of the form and individualize its appearance, and place the overhead light openings in the covering in an original way.

So, for example, just to cover a room that is triangular in plan, a flat shell on a convex contour, a combined covering of four triangular in plan shells of positive curvature, three of negative and one of positive curvature, etc. can be used. design and expressive in architectural form is the covering of a triangular exhibition building in Paris with a combined shell in the form of a vault connected from three trays with a span of 206 m. The trays consist of two wavy shells, braced every three waves with rigidity diaphragms. The use of a wavy shape made it possible to solve not only a purely constructive problem (to achieve the stability of a thin shell), but also ensured the scale of the composition of this unique building, and the closed vault system, traditional for stone architecture, received an individual and sharply modern tectonic interpretation. Equally individual and modern was the compositional interpretation of the reinforced concrete cross vault covering above the square plan of the building of the indoor Olympic skating rink in Grenoble.

Naturally, however, the most modern character of the architecture of long-span coverings with reinforced concrete rigid shells is given by their inherent combinations of geometric shapes in the form of wavy domes and vaults, elementary or combined fragments of shells with surfaces of negative curvature, or combinations of shells of arbitrary geometric shape.

The architectural and compositional capabilities of hanging roofing systems are directly related to their structural form, the possibilities of its individualization and tectonic identification in the volumetric form of the building. In this regard, the greatest potential is provided by hanging tent-type coverings, coverings on a spatial contour, as well as various options for combined hanging systems. The extreme diversity of the external appearance of buildings, which is ensured by the use of hanging coverings on a closed spatial contour, can be seen by comparing such Olympic venues in Moscow as an indoor cycling track and a sports hall in Izmailovo. Unfortunately, the use of a number of technically most efficient suspended structures, for example, single- or double-belt systems with a horizontal annular support contour over round or elliptical buildings, contributes little to the individuality of the external appearance of the building. A load-bearing structure with a small sag is not visible in the external form of the building, and in the interior it is usually hidden by suspended ceilings or lighting installations. Buildings with coatings of this type usually have a composition in the form of a round peripter, the entablature of which is a ring of the supporting contour, and the columns are the pillars supporting it (Yubileiny Sports Palace and the Olympic Hall in St. Petersburg, the Olympic Sports Palace on Mira Avenue in Moscow, etc. .).

Along with the load-bearing structures of the coverings, external, usually non-load-bearing walls, play a significant role in the composition of indoor public buildings. A figurative expression of their non-load-bearing function can be their implementation with a slight deviation from the vertical, giving the building a characteristic silhouette (tapering or widening downward).

A significant part of the surface of the external walls of the hall buildings is occupied by translucent stained glass structures. Their compositional properties and divisions are enriched when two or three translucent materials are combined in the design, for example profile and sheet glass.

Constructive decisions metal coatings long-span buildings can be beam, arched, spatial, hanging Byte, membrane, etc. Considering that in such structures the main load is its own weight, one should strive to reduce it, which is achieved by using high-strength steels and aluminum alloys.

Beam systems (usually trusses) are included in the transverse frames, which improves the static design of work. For spans of more than 60-80 m, it is advisable to use arched coverings (Fig. 1). For large spans, it is advisable to design such coatings pre-stressed. In the arched covering shown in Fig. 2, the upper chord is provided rigid, and the lower chord and the arch grille are made of cables. After installation of the arch, the support units are forced to shift outward, which causes preliminary tension in the lower chord and braces of the arch.

Picture 1. 1 - arch; 2 - tightening; 3 - fixed hinge support; 4 - movable hinge support

Figure 2.1 - cable; 2 - hard belt

Spatial lattice coating structures can be flat two-layer (double-mesh) and curved single-layer (single-mesh) or two-layer. In double-mesh structures, two parallel mesh surfaces are connected to each other by lattice connections.

Mesh systems with a regular structure are called structural and are used, as a rule, in the form of flat coverings. They represent various systems cross trusses (Fig. 3). Structural flat floors, due to their high spatial rigidity, have a small height (1/16-1/20 of the span); they can cover large spans. By installing cantilever overhangs behind the support line, a reduction in bending moments and the weight of the coating is achieved.

Figure 3. 1,2 - upper and lower waist mesh; 3 - braces; 4 - tetrahedron; 5 - octahedron; 6 - supporting capital

Curvilinear spatial coverings usually have a cylindrical or dome surface.

Cylindrical coatings can be single-mesh or double-mesh (curvilinear structures). In the transverse direction they act as a vault, the thrust of which is perceived by the walls or ties.

Dome coverings can have a ribbed (or ribbed-ring) design (Fig. 4a) or a mesh design (Fig. 4b). In ribbed domes, radially located ribs are connected to each other by ring girders. If the latter form a single rigid spatial system with the ribs, then the annular girders work not only for local bending, but as part of the dome system they also perceive annular compressive or tensile forces. In mesh domes, the structure, in addition to ribs and ring elements, includes braces, which creates conditions under which the rods work only on axial forces.

Figure 4. a - ribbed; b - mesh

Suspended coverings consist of a supporting contour and main load-bearing elements in the form of cables or thin steel sheets working in tension. Since the main elements of the covering work in tension, their load-bearing capacity is determined by strength (rather than stability), which allows the effective use of high-strength ropes or sheet steel. Such coatings are very economical, however, increased deformability limits their use for coatings industrial buildings. In addition, given the large expansion of such systems, it is advisable to take the plan form round, oval or polygonal, which makes it easier to perceive the expansion. In this regard, they are mainly used for covering sports buildings, indoor markets, exhibition halls, warehouses, garages and other large span buildings.

The composition of cable-stayed suspended coverings includes flexible cables (steel ropes or reinforcing bars), located in the radial direction (Fig. 5a), in orthogonal directions (Fig. 5b) or parallel to each other in the same direction (Fig. 6). Curvilinear closed support contours work primarily in compression, and central ring- for stretching. In these cases, only vertical forces are transmitted to the structures supporting the coating (walls, columns, frames). In contrast, with open contours, the thrust is transferred to the load-bearing structures of the building, which requires the installation of anchor foundations that work to pull out, or walls with buttresses, etc. Slabs made of light reinforced concrete or metal with polymer insulation, three-layer, etc. are laid on the cable system. .

Figure 5. a - radial arrangement of the cables; b - orthogonal; 1 - shrouds; 2 - support contour; 3 - central ring

Figure 6. 1,2 - shrouds in the middle and at the end, respectively; 3 - support contour; 4 - reinforced concrete slabs; 5 - anchor foundation

Suspended cable roofing systems are very diverse. A tent cable-stayed system is often used, in which the central ring rests on a column and rises to a higher level than the supporting contour one.

An example of such a system is the covering of a bus depot in Kyiv with a diameter of 161 m. The systems described above are single-belt. In addition to them, two-belt systems are also used (especially under high wind loads), in which the stabilization of the coating is carried out using a reverse curvature contour. In such systems, the supporting cables have a downward bend, and the stabilizing ones - upward. Stabilizing cables with a deck installed on them can be located above the load-bearing ones, which causes compression of the struts (Fig. 7a). When stabilizing cables are located under the load-bearing cables, the connections between them will be stretched (Fig. 7b). A third option is also possible, in which the supporting and stabilizing cables intersect, and the racks are compressed in the middle part of the covering and stretched in the outer parts (Fig. 7b).

Figure 7. 1 - stabilizing shrouds; 2 - racks; 3 - load-bearing cables

Hanging thin-sheet systems - membrane coatings - have also become widespread in foreign and domestic practice.

They are a spatial structure made of thin metal sheet(steel or aluminum alloys) several millimeters thick, fixed around the perimeter in the support contour. Their advantages are the combination of load-bearing and enclosing functions, as well as increased industrial production. In some cases, instead of a continuous membrane, the coating is formed from separate thin steel strips that are not connected to each other. The tapes located in two mutually perpendicular directions can be intertwined, which prevents their delamination.

A continuous membrane covering was successfully used for a universal stadium on Mira Avenue in Moscow, the dimensions of which reach 183x224 m (Fig. 8).

Figure 8. Structural diagram of the covering of the universal stadium on Mira Avenue in Moscow (steel membrane 5 mm thick): a - plan; b - longitudinal section; in - transverse

The sports complex, built in Bishkek, includes a hall for 3 thousand spectators, the covering of which is designed in the form of a prestressed membrane-beam hanging system (Fig. 9). The frame of the building is made of a monolithic reinforced concrete building in the form of braced trusses located along the perimeter with plan dimensions of 42.5 x 65.15 m. The covering consists of a 2 mm thick membrane itself, longitudinal girders and transverse beams - struts. The insulation in the form of mineral wool mats is suspended from the membrane from below, the ceiling is made of stamped aluminum elements.

Membrane coverings are also used in a number of other long-span buildings. Thus, in St. Petersburg, a universal sports hall with a diameter of 160 m is covered with a membrane shell 6 mm thick. Similar shells also cover a universal sports hall with plan dimensions of 66x72 m for 5 thousand spectators in Izmailovo (Moscow), the Pioneer swimming pool building with plan dimensions of 30x63 m in Kharkov, etc.

Folded roofing vaults are a spatial structure that can be made of metal (steel, aluminum alloys), reinforced concrete, and plastics.

Such coatings made of aluminum alloys are especially effective. The main structural element in the latter can be a diamond-shaped sheet (Fig. 10), bent along a larger diagonal. The diamond-shaped elements can be connected to each other using cylindrical hinges or rigid flange joints. To increase the spatial rigidity of the coating (especially with hinge joints), it is necessary

provide for the installation of longitudinal ties along the protruding nodes of the folded arch.

Figure 9. 1 - building frame; 2 - membrane-beam hanging system

Figure 10.

Modern engineering and construction technologies make it possible to erect unique long-span structures and spatial structures that have distances between load-bearing supports of more than 40 meters, making them reliable and functional. Most often these are factory machine-building and shipbuilding workshops, hangars, parking lots, stadiums, station buildings, theaters and galleries.

Long-span metal constructions They have elasticity and allow you to create various types of interfaces for constructing expressive geometric shapes and architectural solutions of any complexity. Moreover, they contain many stress concentrators. Correct and uniform distribution of high load-bearing loads between structural elements is important, since under the influence of the natural gravity of the structure and wobbling external factors Dangerous damage may occur.

Structures based on long-span beams are at particular risk of developing deformations and cracks during construction and during operation, which subsequently lead to destruction. Therefore, they require constant real-time monitoring and monitoring of their condition to ensure safety conditions.

Typical reasons that cause problems in long-span buildings:

• poorly conducted geophysical and geodetic surveys, replacement of experimental calculations with modeling;
• design errors, miscalculations in determining loads and locations of geometric centers, displacement of axes, violation of the principles of straightness or rigidity of elements;
• violation of manufacturing technologies or rules for installation of structures, incorrect node connections, use of unsuitable building materials (for example, choosing a type of steel unsuitable for specific conditions);
• uneven sedimentary processes affecting the stability and integrity of foundations, supporting elements, vaults and ceilings;
• improper operation, abnormal loads and emergency impacts;
• temporary wear and tear;
• the influence of unfavorable natural factors (wind pressure, displacement of soil layers and movement groundwater, seismic processes, temperature and humidity conditions in which rusting of metal structural elements, destruction of concrete, etc. occurs);
• vibrations created by traffic and nearby construction work.

As a result of the influence of these factors and causes, deformations of the main supports and loss of their load-bearing capabilities, deflections and displacements of span beams, and progressive destruction occur. This creates a danger to human life and leads to economic losses associated with the need to compensate for damage from accidents and carry out repairs.

Object condition monitoring

Monitoring of long-span buildings and structures allows you to track physical wear and tear, reduce the load-bearing capacity of engineering structures, identify unfavorable changes, the appearance of defects and damage, detect dangerous stress-strain states, monitor their exceedance of the limit values ​​provided for by the project, and timely notice exceedances of established reliability coefficients and maximum permissible values. the magnitude of deviations of the observed parameters.

Monitoring is carried out using special high-precision measuring instruments, control devices, registrars significant parameters and reliability indicators that capture electromagnetic and ultrasonic vibrations, sensors and geodetic markers, computerized dispatch consoles, automatic equipment And signaling systems alerts.
Long-span buildings are equipped engineering systems monitoring and management, which are informationally linked with the duty dispatch services of the Ministry of Emergency Situations. Such systems make it possible to collect data simultaneously from many transmitters and according to different parameters. This information flows into a single center, is integrated, analyzed using specified algorithms, and ultimately produces a schematic and visually presented result indicating the state of the structure under study.

Based on this, monitoring specialists can draw up conclusions, forecasts and reports with reasonable diagnostics of objects, recommendations and programs of effective measures to eliminate existing defects and destabilizing factors, minimize risks and threats of emergency situations, avoid them and prevent damage. In the event of emergencies and emergency situations, rescue services are promptly informed about them.

Specialists in engineering and construction monitoring

The SMIS Expert company develops system solutions for assessing the vulnerability and diagnosing problems of large-span structures, monitoring support for the construction and operation of buildings for various purposes. We have extensive experience and highly qualified specialists. We use modern scientific knowledge and innovative technologies. We provide professional geodetic monitoring and research of all types of objects to determine the degree of their reliability, safety and durability. We sell high-precision measuring equipment and instruments.