The structural system of buildings consists of interconnected building elements. All vertical and horizontal components work together and provide stability, rigidity and strength of the erected structures. Horizontal structures take on household and operational loads and transfer them to a vertical supporting frame. The elements of the building frame counteract wind forces, perceive the loads from human activity, bear the weight of the horizontal components and transmit the impacts to the foundation and foundation.
Horizontal bearing members
These structures are represented in the structure by elements that are long in plan. The structural system of buildings assumes that slabs, monolithic sections, beams, crossbars and trusses are designed from concrete, metal, wood, depending on the required load and span dimensions.
Initially, at the dawn of the construction era, horizontal ceilings were built on the principle of support beams with decking from the covering material. But modern design of buildings and structuresuses reinforced concrete hollow, ribbed, U-shaped, trough floor slabs, which simultaneously combine in their work the supporting crossbars and the area suitable for operation.
Transmission of loads from horizontal members
It is carried out according to the scheme, when the impact is transferred to all bearing vertical elements or distributed to structural rigid walls, diaphragms, connections between racks or columns selected for this purpose. For industrial structures, the design scheme provides for a combined method of transferring loads with the distribution of horizontal forces on the stiffeners and proportionally between the vertical components.
Floor slabs are referred to as load-bearing stiffening diaphragms, they combine the horizontal distribution of loads and their transfer to vertical elements. Reinforced concrete slabs level the area in the room and transfer forces, due to the rigid connection with vertical structures.
The use of reinforced concrete is due to the fact that, according to fire safety requirements, slabs of high-rise buildings must be made of non-combustible material. The economic justification for the cost of manufacturing floor panels made it possible to use them in large quantities in buildings of any type. Slabs in the building structure are prefabricated, monolithic or precast-monolithic.
Variety of vertical load-bearing elements
In accordance with the type of vertical elements that collect forces, the structural scheme of buildings is divided intofour main types:
- planar system contains only walls and stiffeners;
- frame and frame, consisting of rod and enclosing (diaphragm and wall) components;
- stem, accommodating the entire height of the building internal rods of volume-spatial hollow section;
- Shell system using external volumetric solutions in the form of a closed-type shell with thin elements.
Industrial constructive and technological systems of buildings
Residential buildings have their own typological features, they include vertical load-bearing elements located in the plane of the walls. The use of columns as the main structures already at the initial stage of industrial development made it possible to distinguish four design schemes:
- with transverse placement of supporting crossbars;
- with longitudinal bearing beams;
- with a cross system for arranging long elements;
- without using any girders in the design.
Designing buildings and structures according to the industrial method made it possible not only to make the work of floors more interconnected, but also to expand the number of types of vertical load-bearing elements. More recently, a constructive solution using closed-type stiffeners has been used. These elements are usually located in the central part of the building, so that it is convenient to place ventilation shafts, elevators, and garbage chutes there. Large buildings require installationmultiple stiffeners.
The structural scheme in the form of load-bearing shells is a young architectural solution. Its appearance can imitate an abundance of prisms, cylinders, pyramids or other three-dimensional geometric shapes.
Choosing a constructive solution
The building scheme is a generalized static characteristic of the building, not intended to determine the material of production and the method of construction. For example, a frameless wall flat construction works effectively at the same time when made of brick, wood, concrete, foam concrete and many other modern materials.
The combined structural system of buildings describes a variant of the design solution for the composition and type of arrangement of the main longitudinal and transverse elements in different directions. Its type is chosen at the initial design stage, taking into account the advanced technological operational requirements and a rational space-planning solution.
In addition to these aspects, when choosing a design scheme, the nature of the distribution of horizontal forces and their interaction with vertical frame elements are taken into account. Structural systems of industrial buildings are determined taking into account the influence of the architectural solution and the type of building. The choice of the project is influenced by the number of storeys of the building and the construction conditions in the engineering and geological plan.
Application of various constructive solutions in the design of houses and buildings
Frame solution with frame spatialvariant is used in the construction of seismological cataclysm-resistant buildings and high-rise buildings over nine floors, as well as in other buildings under normal conditions. This is the main developed building design system, rarely used in housing construction due to unreasonable economic high cost.
The frameless type of spatial solution is used in the construction of residential buildings, used to design skyscrapers up to 30 floors. The volume-block constructive system of buildings consists of load-bearing elements made up of three-dimensional self-supporting blocks placed one on top of the other. The so-called poles work in a bundle, thanks to a strong connection with each other using rigid or flexible connected elements.
Frame-diaphragm construction solution
The system refers to combined schemes with an incomplete frame and is based on the distribution of stationary equilibrium functions between rod and wall bearing products. Structural systems of high-rise buildings are built on the principle of transferring horizontal loads to vertical wall diaphragms, while vertical forces occurring in the frame act on the bar elements. Most high-rise residential-type panel-frame buildings are erected using this method under normal construction conditions and in seismologically hazardous areas.
Frame-block spatial solution
Based on the joint work of blocks andframe elements, and volumetric structures act as load-bearing or hinged elements. With the help of reinforced concrete blocks, they fill the space in the supporting frame lattice. Loaded elements are installed one on top of the other on horizontal platforms of the frame, which are arranged through 3-5 floors. Such a system has proven itself in buildings above 12 floors.
Architectural and economic requirements determine the frame scheme when choosing a project. Long-length elements are designed so that they do not infringe on the planning solution, while the ceiling crossbars do not protrude from the surface in residential buildings. The transverse arrangement of the purlins is typical for high-rise buildings with a regular cellular structure in plan (hotels, hostels), while the step of the bearing crossbars alternates with walls and partitions. The longitudinal arrangement of long loaded beams is used in apartment-type residential building projects.
The beamless frame is used in the construction of residential buildings, if the use of prefabricated reinforced concrete structures is impractical due to the lack of large industrial associations in the region. The beamless system is characterized by low reliability and high cost; it is used in the construction of monolithic and combined prefabricated bulk structures using the method of raising floors and sliding formwork.
Building building systems
This concept characterizes a constructive solution in a complex technological solution for the method of building a structure and the choice of material for the elements and nodes used. constructivebuilding systems of buildings are designed with load-bearing walls made of small blocks, bricks, natural stone, ceramics or concrete. Systems are divided into prefabricated and traditional.
Traditional building pattern
The system is based on manual laying of walls. Speaking about the industrial method of construction, it should be noted that the construction of enclosing elements remains from the traditional scheme. All other parts of the building, such as ceilings, stairs, girders, columns and others, are adopted by the industry from the prefabricated project, which elevates traditional construction to a high level of the industry.
The advantage of the traditional system is that the small dimensions of the wall stones make it possible to build houses of various shapes and heights. Brick walls are reliably operated for a long time, have a high fire resistance threshold, the front masonry does not require plastering. The disadvantages include greater labor intensity and the dependence of strength characteristics on the technology of the manufacturer and the skill of the bricklayer.
Complete system
According to this scheme, projects of houses are carried out, the construction of which is based on the installation of large prefabricated elements (panels, blocks) made of brick, ceramics, reinforced concrete. Fully assembled objects are built according to systems:
- from large blocks;
- using panels;
- with hanging wall plates on the frame;
- from bulk blocks;
- from monolithic concrete.
Large blockbuilding system
These types of structural building systems are used in the construction of residential buildings up to 22 floors high. Large horizontal blocks are placed according to the type of brickwork with dressing of seams. The advantages of a large-block system are the simplicity and speed of installation of elements, the ability to use various materials. A limited number of standard sizes requires a small investment, while a variety of shapes are built.
Panel structure structures
According to this scheme, houses with a height of 14 to 30 floors are designed, respectively, in seismic regions and in ordinary conditions. The wall structure consists of separate panels installed one on top of the other without dressing the seams with cement mortar. Their stability is ensured by welding of embedded parts, and during operation by a strong connection of bonds and joints. The use of the system reduces labor intensity up to 40%, the cost of construction up to 7%, reduces the total mass of the building by 20-30%.
Frame-panel solution of the project
Buildings are erected with a load-bearing frame made of metal or precast concrete and framed with hinged panels of various materials. It is allowed to build buildings of this type up to 30 floors. It is mainly used in public buildings, as in housing construction it is inferior to panel in terms of economic and technical indicators.
3D block building
This construction method belongs to industrial types and consists in the installation of spatial elements of reinforced concrete weighing up to 25 tons, containing in volumeone room (kitchen, room, bathroom, etc.) The blocks are built without dressing the seams. This method allows to reduce the labor intensity by another 15% compared to the panel method. The production of large-panel blocks is 15% more expensive than panels. They build low-rise houses in seismic areas and 16-storey houses in normal conditions.
Monolithic building systems
They are used for high-rise buildings. Structural systems of monolithic buildings include structures in which all load-bearing elements and components are made using reinforced concrete. Combined schemes of a prefabricated monolithic house involve the collection of loads on the frame from precast concrete elements. Monolithic buildings are designed without a frame, while prefabricated monolithic buildings are built with or without a frame.
Industrial methods in this area include construction using concrete in formwork:
- sliding;
- volume adjustable;
- panelboard large.
The erection of monolithic buildings on the frame is performed by the methods:
- floor lifting;
- departure of floors.
The monolithic system corresponds in strength to prefabricated building types, and is widely used in areas where local materials can be actively used and no investment in the development of the production base.
