The use of the KUB-2.5 frame-prefabricated system in construction saves up to 28% of the total costs, which increases the profitability of the facility by approximately 60%.

Frame Unified Transomless “CUBE” is a building system, the main difference of which is the use of industrially manufactured elements of the building frame and their installation on construction site. Housing developed by TsNIIEP back in Soviet era and improved by the authors of the development, who registered the invention at NPO "KUB", the prefabricated frame system is intended for the construction of buildings up to 25 floors high in 4 climatic zones seismic resistance up to 9 points inclusive.

	Columns
		Wall panel in the ground (for water separation)

Analyzing building systems in terms of cost, planning capabilities, labor costs, construction speed, architectural solutions experts agree that in the next 5-7 years, industrial prefabricated frames will confidently occupy 35-40% of the market construction technologies, displacing large-panel and frame-monolithic schemes from the leading positions, not to mention construction from small-piece materials. The arguments are quite obvious:

Firstly, frame structures more versatile - they can be used in all types construction production- during the construction of residential and office buildings, industrial facilities, shopping and parking complexes;

secondly, the advantage of modern frame technologies in that they provide significantly greater freedom in the choice of architectural solutions;

thirdly, the cost-effectiveness of a prefabricated frame, compared to traditional schemes, is 22-28% of the total cost;

and, of course, the main indicator is a reduction in construction time, which allows the customer to quickly return the investment with a profit, and the consumer to celebrate a housewarming much earlier.

What is a team transomless frame?

Products of the KS "KUB-2.5" have a simple geometric shape and a minimum number of main standard sizes (4).

The frame consists of columns square section 400x400 mm and flat floor panels 3x3m, 160 mm thick.

Depending on their location in plan, floor panels are divided into above-column, inter-column and middle.

The division of the floor is designed in such a way that the joints of the panels are located in zones where the magnitude of the bending moments is zero. The spatial rigidity of the structure is ensured by the monolithic connection of elements (floors and columns) and, if necessary, the inclusion of connections and diaphragms in the system.

Installation of structures is carried out in the following order:

Columns are mounted and embedded in foundation glasses;

Above-column panels are installed and welded to the column reinforcement;

Inter-column and middle panels are installed.

After installing the fasteners, the seams between the panels are sealed. At the same time, the joints of the above-column slabs with the columns are sealed along the entire floor at this level.

The design of column joints provides for forced installation, in which the fixing rod of the upper column must enter the nozzle of the lower column.

The assembly contains only assembly seams.

The structural building system "KUB-2.5" has been reviewed and recommended for use

The prefabricated transomless frame system has proven itself positively in more than 30 regions of Russia. The number of its supporters and development volumes are growing every year.

The structural system of the crossbar-less prefabricated reinforced concrete frame KUB-2.5 allows for a variety of climatic conditions to almost completely ensure the construction of the entire range of urban structures: housing, administrative, social, cultural and domestic buildings, multi-level garages, warehouses, some industrial buildings (with spans up to 12 m).

All reinforced concrete structures the systems make it possible to design (construct) buildings up to the first degree of fire resistance, which ensures its use for buildings of various heights: cottages, low-rise and multi-storey (up to 75 meters) buildings.

The minimum number of vertical frame elements and the absence of crossbars allows you to create free layouts of premises within the boundaries of load-bearing and enclosing structures for various purposes. Partitions can be located anywhere in the architectural plan, both during design and construction, and during the operation of the building. The system provides the possibility of redevelopment of premises in accordance with any current needs during the operation of the building without compromising the structural stability of the building (gives freedom in organization on the first floors in residential buildings offices, shops, sports and recreational and residential complexes).

The supporting frame of the building consists only of internal elements(columns, floors and, if necessary, connections or diaphragms). Almost any façade solutions can be used as external enclosing structures (walls): lightweight, heat-efficient stone (including brick-lined), various curtain panels, ventilated facades, stained-glass fencing, etc.

The “CUBE” system allows you to cantilever the floor slabs beyond the axes of the outer columns (up to 1.5 m) and give the slabs, along their outer edge, almost any shape in plan. The system includes limitless possibilities to enrich the plasticity of facades, which can satisfy any, the most sophisticated tastes, and are limited only by the imagination of the architect, the customer’s requests and the requirements of the standards.

Design features of the system

Today, on the Russian market, the KUB-2.5 non-transom frame structural system is the only one in which the non-transom frame is fully prefabricated.

The frame of a building (structure) in a structural frameless frame system is spatial design, such as a “shelf” of prefabricated, prefabricated monolithic or monolithic design. Columns serve as frame supports, floor slabs serve as crossbars, and braces or diaphragms are used for stiffening elements. Stairs, ventilation units, and elevator shafts can be used in any manner mastered by manufacturing plants. Load capacity floors allow the use of the frame in buildings with a load intensity per floor of no more than 1300 kg/m2 (modification KUB-2.5K up to 2500 kg/m2).

The KUB-2.5 structural system is based on an original interface between two main elements - a panel and a column using an embedded part - a steel shell of a special design connected to reinforcement cages located in the body of the panel. The concrete in this unit operates under conditions of all-round compression, as a result of which it self-strengthens. This made it possible to avoid welding at the joint of the columns; only assembly seams are present in the assembly.

The joints of the elements that make up the transomless frame as a whole are monolid, forming a frame structural system, the crossbars of which are the ceilings.

The division of the floor is designed in such a way that the joints of the panels are located in zones where the magnitude of the bending moments is zero.

An important advantage of the system is the possibility of using higher classes of concrete (up to B60) in columns, which affects the results of reinforcement and the preservation of typical cross sections columns 400×400. Columns manufactured on a construction site (in monolithic housing construction) can have a concrete class of up to B30, and this imposes corresponding restrictions on the design of racks.

External walls are not load-bearing, there is no need to build foundations under them, and they do not need to be designed as strong as is done in frameless buildings. The load on the base of the frame is 25% lower than in a monolithic version. Regardless of the ground conditions, the volume of foundations required to distribute forces to the foundation from the above-ground part of buildings made in the structures of the “KUB-2.5” system will always be minimal, because The dead weight of the frame is also minimal due to the achieved optimization of all sections.

Transomless frame designs are intended for use in different regions Russia, including in areas with seismicity of 7-9 points.

The strength of the KUB-2.5 frame structures is confirmed by technical calculations and numerous tests:

• KUB designs were reviewed by the Scientific and Technical Council of the State Committee for Architecture under the USSR State Construction Committee and recommended for use by letter No. IP-7-3691 dated September 19, 1986;
• TsNIISK them. Kucherenko of the USSR State Construction Committee, the KUB frame is recommended for use (conclusion dated March 15, 1990);
• Dynamic testing laboratory of TsNIIEP housing under the direction of G.N. Ashkinadze.

IN recent years More than a thousand objects have been built in Russia and abroad using the KUB-2.5 transomless frame.

Features of construction in the system

The universal structural system "KUB-2.5" is highly industrialized, which is expressed in a high degree of factory readiness of its constituent elements. All elements are produced at reinforced concrete factories.

At the construction site, only the installation of finished elements is carried out using mechanized means, thereby ensuring a high pace of construction.

The factory technology used in the system for the production of building elements allows the maximum transfer of labor costs of builders to workshop conditions, thereby significantly reducing the risks of both natural and human factors on the construction site.

When developing the frame of the KUB system, solutions were used that significantly shortened the construction process of constructing the building frame:

• installation vertical structures produced on several floors at once;
• the design of the column joint does not require welding of the load-bearing reinforcement;
• there is no need to install (and then repeatedly reinstall) formwork;
• the designs of the joints of columns and floor panels between each other do not require the installation of special formwork to embed the joint, which reduces construction labor intensity;
• KUB-2.5 slab products are stored in stacks of up to 10 pieces, which allows you to successfully work in a cramped construction site.

In addition, the installation of the frame can be carried out in any weather, and a small number of workers on the construction site reduces the likelihood of using unskilled labor.

Economic justification

Reinforced concrete structures of the KUB-2.5 system are not only rational, but also optimal due to the solutions embedded in them. Rationality is expressed in reasonably substantiated, thoughtful constructive solutions, providing a minimum number building materials(steel and concrete) and labor costs.

Material savings:

• consumption of reinforced concrete in the frame (floor panels, columns, grouting joints) is: 0.179 m³ per 1 m² of floor area;
• steel consumption in reinforced concrete frame elements, incl. reinforcement and rolled, is: 14.3 kg per 1 m² of floor area.

Labor savings:

• construction labor costs - 0.51 people. hour per 1 m² of floor area;
• factory labor costs – 1.92 people. hour per 1 m² of floor area.

The universal structural system of prefabricated monolithic crossbar-less frame “KUB-2.5” is designed on the basis of developed and proven methods, which significantly reduces the time required to complete the work.

The production and construction of the frame is carried out on the basis of time-tested effective organization construction production.

The mechanical ratio of labor at all levels of production of prefabricated reinforced concrete products and installation of frames reaches 90%.

All-weather, versatility and flow-rate construction of the frame, as well as preliminary design studies make it possible to fairly accurately plan the construction period.

Precast concrete does not require electrical heating, which saves energy costs.

The speed of construction reduces the operating time of tower cranes, and therefore the rent for their operation.

The use of a prefabricated reinforced concrete frame of the KUB-2.5 system actually reduces construction time and reduces its cost.

Transomless reinforced concrete frame systems in modern construction

Prefabricated reinforced concrete frame "KUB-2.5" is a universal structure for the construction of residential, public and industrial buildings both in normal construction conditions and in areas with seismicity of no more than 9 points inclusive on a 12-point scale. The universal structural system “KUB-2.5” allows, in a variety of climatic, relief, and seismic conditions, to almost completely ensure the construction of residential buildings, social and cultural buildings, warehouse complexes, multi-story parking lots, etc. - i.e. implement residential development and objects of the industrial and communal zone with it in a single constructive key, in a single technology for the manufacture and installation of building structures.

Residential buildings, social facilities, administrative buildings - dozens and hundreds of objects were erected during this time using a frameless frame in many cities of Russia and the CIS - Moscow, St. Petersburg, Nizhny Novgorod, Kyiv and many other cities.

Figure 1

Axonometric view of load-bearing structures

a) and moment diagrams (b) of the crossbar-less frame “Cube-2.5”: NK - above-column slab; MK - intercolumn slab; PVC plate insert; K-column

Today, the KUB-2.5 non-transom frame structural construction system is the only building system on the Russian market in which the frame is fully prefabricated; only the joints between the structural elements of the frame are monolithic: the column and the slab. This makes its use promising in the North, where the use of monolithic reinforced concrete is limited by natural factors. The factory technology used in this system for the production of building elements transfers the labor costs of builders to the workshop as much as possible, thereby significantly reducing the risks of both natural and human factors on the construction site, and also significantly reduces construction time.

The design of the crossbar-less frame of the KUB-2.5 system is a frame (frame-braced) prefabricated monolithic frame with capitalless ceilings (Fig. 1, a). The division of the floor is designed in such a way that the joints of the panels are located in zones where the magnitude of the bending moments is zero (Fig. 1, b). Spatial rigidity is ensured by the monolithic connection of elements (floors and columns) and, if necessary, the inclusion of braces or diaphragms in the system.

The developed frame structures provide floor heights of 2.8 m, 3.0 m, and 3.3 m with a main grid of columns of 6.0 x 6.0 m. Spans of 3.0 m, 6.0 m and 12.0 m are possible.

Figure 2 Options for external enclosing structures of the crossbar-less frame “Cube-2.5”

The structural system of the transomless frame has 2 load-bearing elements: a column and a floor panel, which makes it possible to construct external enclosing structures in various options. External walls according to their static function can be either curtain walls (Fig. 2, a-b) or self-supporting (Fig. 2, c). Material: concrete, foam blocks, brick. Insulation can be located both on the inside and on the outside, including using ventilated facades. As interior walls and partitions, structures made of various materials can also be used.

Figure 3 Options for floor slabs and joints of floor slabs

crossbar-less frame "Cube-2.5"

Flat floor panels are used in two modifications: single-module with dimensions 2980x2980x160 mm (maximum size 2980x5980x160 mm) and two-module with dimensions 2980x5980x160 mm.

Single-module floor panels are divided depending on their location in the frame (Fig. 3,b) into:

above-column, inter-column, middle (insert slabs).

Two-module panels are formed by combining two adjacent panels: above-column and inter-column; intercolumnar and middle (Fig. 3, a).

The use of two-module panels is preferable, as this allows you to double the installation time and save on caulking joints.

When installing the panels, the reinforcing outlets of the ends are combined in such a way that a loop is formed into which the reinforcement is inserted and then tied (Fig. 3, c). The seams between the slabs are used to pass utility lines.

The columns are designed in two types: a section of 400x400 mm with a maximum length of 14600 mm and a section of 200x400 mm with a maximum length of 9200 mm (Fig. 4, 5).

At the floor level, the columns have exposed reinforcement (Fig. 4).

Figure 4 Columns of the crossbar-less frame “Cube-2.5”

Figure 5 Columns and joints of columns of the crossbar-less frame “Cube-2.5”

The joint of the columns provides for forced installation, in which the fixing rod of the lower end of the upper column must enter the nozzle of the upper end of the lower column (Fig. 5, c). In this case, the installation of formwork is not required, welding of reinforcement is not provided, and construction labor intensity is reduced. The column also has vertical marks on all vertical faces for ease of geodetic control when installing columns (Fig. 5,b).

The interface between two main elements - the panel and the column - was developed using an embedded part - a steel shell (Fig. 5d) connected to reinforcement cages located in the body of the panel. The concrete in this unit operates under conditions of all-round compression, as a result of which it self-strengthens. This made it possible to avoid welding at the joint of the columns. The assembly contains only assembly seams.

The installation of the structures that make up the transomless frame as a whole is carried out in the following order: first, the columns are installed, aligned and embedded in the foundation cups; then the above-column panels are installed at the design level and welded to the column reinforcement; after this, the intercolumn and middle panels are mounted “dry” using concrete mounting tables (Fig. 3, d) provided for by the design of the panels; joints between panels are concreted

The practice of using the unified transomless capitalless frame of the KUB-2.5 system has shown its advantages over other systems:

Today, this is practically the only system that really gives complete freedom of planning decisions (Fig. 6). With its help, you can build buildings with a height of 2 to 25 floors, with any floor height.

Compared to traditional technologies For the construction of multi-storey buildings, this technology is economical: the reduced consumption of concrete and steel gives an overall reduction in construction costs by 5-7%, even taking into account the costs of the factory technology for manufacturing elements.

The advantage of the system compared to monolithic frames is expressed in: a reduced mass of steel in the ceiling (78.9 kg per 1 m3 with a column spacing of 6x6 m); in the possibility of using higher classes of concrete (up to B60) in columns, which affects the results of reinforcement and the preservation of typical cross-sections of columns of 400 x 400 mm.

All elements of the system, in contrast to the monolithic frame technology, are manufactured in a factory manner, which makes it possible to almost completely eliminate the possibility of defects, since all components of the crossbar-less frame structure undergo strict production control at the enterprise.

The next factor in determining the benefits of this building system is high speed and ease of installation.

When constructing objects, a team of 5 people installs up to 300 m2 of floors per shift, and assembles the spatial structure at a rate of 200 m2, regardless of the time of year and weather conditions. If the installers have good skills, the frame of one section is 16- storey building can be completed in three months with the installation of all reinforced concrete elements.

By increasing the speed of frame construction and saving basic materials, the overall economic efficiency up to 20% of the total cost of constructing the above-ground part, which is confirmed by calculations and practice of using the system in 27 regions of Russia.

Figure 2.5 Example of a 16-storey residential building in the “Cube-2.5” frameless frame system

"KUB-2.5" makes it possible to produce prefabricated elements of any applicable number of storeys in the same types of forms.

To implement residential development (residential and public buildings), it is necessary to have 4 types of forms: column, above-column slab, inter-column slab, middle slab. Stairs, ventilation blocks, elevator shafts can be used in any other structural system mastered by factories producing reinforced concrete products.

DESCRIPTION OF THE INFORMATION SYSTEM NPO "KUB"

KUB-2.5 structures are designed for the construction of buildings up to 25 floors and higher in climatic regions I-IV both under normal conditions and under conditions of increased seismic activity up to 8 points. It is also possible to construct buildings up to 16 floors high and in areas with seismicity up to 9 points.
The frame is easy to manufacture and install. Frame products have a simple geometric shape and have a limited number of standard sizes, which makes it much easier to master. The stock of forms is minimal; the forms themselves are simple and technologically advanced.
Elements of a transomless frame can be easily manufactured in newly developed areas, in the absence of an industrial base, as well as in places where the production of frames of existing series has not yet been established. The transomless frame has architectural, planning and design advantages before traditional block ones.
In some cases, a smooth ceiling allows you to avoid expensive false ceilings required for hygienic, aesthetic or technical requirements.
The reduced construction dimensions of the floor make it possible to reduce the cubic capacity of the building by 5-8%. The presence of a cantilever part along the perimeter of the ceiling makes it possible to conveniently solve temperature-sedimentation joints, adjoining to other buildings, installing galleries and sun protection elements for the southern regions.

One of the advantages of the frame is the reduced consumption of steel and cement per 1 sq.m of flooring compared to frame systems, applied both domestically and abroad.
Another advantage is ease of installation.
The form-building capabilities of the frame have a wide range from single-story to multi-story buildings with complex architectural and spatial solutions.
Experimental and theoretical studies conducted at the TsNIIEP Institute of Housing confirmed the rigidity and strength qualities of the structure, as well as the reliability of the calculation premises.

The frame without transoms consists of square columns and flat floor panels. The floor panels have plan dimensions of 2.98 x 2.98 m, so the gap between them is only 20 mm and this makes it possible to embed the seams without installing formwork. The thickness of the panels is 160 mm. The system provides two-module panels obtained by combining two adjacent panels: 1. Supracolumnar and intercolumnar. 2. Intercolumnar and middle.

This allows you to speed up installation by half and save on sealing joints. Floor panels, depending on their location in plan, are divided into above-column, inter-column and insert panels. The division of the floor is designed in such a way that the joints of the panels are located in zones where the magnitude of the bending moments is zero. The spatial rigidity of the structure is ensured by the monolithic connection of elements (floors and columns) and, if necessary, by the inclusion of connections and diaphragms in the system.

After installing the reinforcement in the seams between the panels, the seams are grouted, and at the same time the joints of the above-column slabs with the columns are grouted throughout the entire floor at this level. The seams between the slabs are used to pass utility lines. Frame structures are designed for the construction of buildings using a frame or frame-braced design. The number of storeys according to the frame scheme is limited to 5 floors; according to the frame-braced scheme it is practically unlimited, provided that the strength properties of the columns are ensured by increasing the percentage of reinforcement for the introduction of rigid reinforcement. The joints of the frame elements are monolid, forming a frame structural system, the crossbars of which are the floors. Installation of multi-storey frame frames is carried out using simple devices. Mobile or tower cranes with a carrying capacity of 5 tons and above. The installation of structures is carried out in the following order: columns are mounted and embedded in the foundation glasses, above-column panels are installed and welded to the column reinforcement, then inter-column panels and insert panels are installed.

The range of products provided in the KUB-2.5 releases allows you to design buildings with spans of 6 and 3 m with column spacing of 6 and 3 m, floor heights of 2.8; 3.0; 3.3 m. The frame structures involve the use of external internal walls from both piece material, and in the form of large-sized elements - panels.

The external wall panels are designed as vertically cut single-layer expanded clay concrete panels.
Builders note the ease of installation of the frame, the ease of mastering it on the construction site, the possibility of achieving high performance labor.

The frame of a building (structure) in a structural frameless frame system is a spatial structure, such as a “shelf” of prefabricated, prefabricated monolithic or monolithic design. Columns serve as frame supports, floor slabs serve as crossbars, and braces or diaphragms are used for stiffening elements. Standard staircases, ventilation units, and elevator shafts can be used. The load-bearing capacity of the floors allows the use of the frame in buildings with a load intensity per floor of up to 1300 kg/m2 (modification "KUB-2.5K" up to 2500 kg/m2).

The “CUBE 2.5” structural SYSTEM is based on an original unit for connecting two main elements - a panel and a column using an embedded material - a steel shell of a special design connected to reinforcement cages located in the body of the panel. The concrete in this unit operates under conditions of all-round compression, as a result of which it self-strengthens. This made it possible to avoid welding at the joint of the columns; only assembly seams are present in the assembly.

The division of the floor is designed in such a way that the joints of the panels are located in zones where the magnitude of the bending moments is zero. The joints of the elements that make up the transomless frame as a whole are monolithic, forming a frame structural system, the crossbars of which are the floors.

An important advantage of the system is the ability to use high-grade concrete (up to B60) in columns, which affects the results of reinforcement and maintains the typical cross-sections of 400*400 columns. Columns manufactured on a construction site (in monolithic housing construction) can have a concrete class of up to B30, and this imposes corresponding restrictions on the design of racks.

The load on the base of a building built using the CUBE-2.5 SYSTEM frame is 25% less than that of a similar monolithic one. The dead weight of the frame is minimal due to the achieved optimization of all sections. Regardless of the ground conditions, the volume of foundations required to distribute forces on the foundation from the above-ground part of buildings made in “KUB-2.5” structures will always be lower.

Transom-less frame structures are intended for use in various regions of Russia, including areas with seismicity of 7-9 points.

The strength of the KUB-2.5 frame structures is confirmed by technical calculations and numerous tests:

• KUB designs were reviewed by the NTS of the State Committee for Architecture under the USSR State Construction Committee and letter No. IP-7-3691 dated September 19, 1986 and recommended for use;
• TsNIISK named after Kucherenko of the USSR State Construction Committee, the KUB frame is recommended for use (conclusion dated March 15, 1990);
• Dynamic testing laboratory of TsNIIEP housing under the direction of G.N. Ashkinadze. (successfully passed dynamic tests).
• Today, more than a thousand objects built using transomless frames are successfully operated in Russia and abroad.