The structural system of buildings consists of interconnected structural elements. All vertical and horizontal components work in a single aggregate and provide stability, rigidity and strength of the erected structures. Horizontal structures take on household and operational loads and transfer them to the vertical supporting frame. Elements of the skeleton of the building counteract wind forces, perceive loads from human activity, bear the weight of horizontal components and transmit the effects on the foundation and foundation.
Horizontal supporting elements
These structures are represented in the building by elements that, in terms of plan, are of great length. The structural system of buildings suggests that slabs, monolithic sections, beams, beams and trusses are designed from concrete, metal, wood, depending on the required load and span.
Initially, at the dawn of the construction era, horizontal ceilings were built on the principle of support beams with flooring made of coating material. But the modern design of buildings and structures uses reinforced concrete hollow, ribbed, p-shaped, trough floor slabs, which simultaneously combine support crossbars and an area suitable for operation in their work.
Transfer of loads from horizontal elements
It is carried out according to the scheme, when the effect is transmitted to all vertical bearing elements or distributed to the structural rigid walls, diaphragms, connections between the uprights or columns chosen for this purpose. For industrial buildings, the design scheme provides 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 bearing diaphragms of rigidity, they combine the horizontal distribution of loads and transfer them to vertical elements. Reinforced concrete slabs equalize 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 fireproof material. The economic justification of the costs of the manufacture of floor panels made it possible to use them massively in buildings of any type. Plates in the building structure are prefabricated, monolithic or precast monolithic.
Variety of vertical load-bearing elements
In accordance with the applicable type of vertical elements that collect efforts, the structural design of buildings is divided into four main types:
- a planar system contains only walls and stiffeners;
- frame and frame, consisting of rod and enclosing (diaphragm and wall) components;
- barrel, containing the entire height of the building internal rods of volumetric-spatial hollow section;
- shell system that uses external volumetric solutions in the form of a closed shell with thin elements.
Industrial structural and technological systems of buildings
Residential houses have their own typological characteristics, 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 support crossbars;
- with a longitudinal arrangement of bearing beams;
- with a cross system for long elements;
- without using any runs in the design.
The design of buildings and structures according to the industrial method allowed 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-loop stiffeners is used. These elements are usually located in the central part of the structure, so that it is convenient to place vent shafts, elevators, garbage chutes there. Larger buildings require the installation of several stiffeners.
Structural design in the form of bearing shells is a young architectural solution. Its appearance can imitate the abundance of prisms, cylinders, pyramids or other volumetric geometric shapes.
Design decision
The building scheme is a generalized static characteristic of the building, which does not aim to determine the material of production and the method of construction. For example, a frameless wall flat design simultaneously works efficiently in brick, wood, concrete, foam concrete and many other modern materials.
The combined structural system of buildings describes a 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 stage of design , taking into account advanced technological operational requirements and a rational space-planning solution.
In addition to these aspects, the nature of the distribution of horizontal forces and their interaction with vertical frame elements are taken into account when choosing a design scheme. Structural systems of industrial buildings are determined taking into account the influence of the architectural solution and the type of structure. The choice of project is influenced by the number of storeys of the building and the construction conditions in the engineering geological plan.
The use of various design solutions in the design of houses and buildings
The frame solution with a spatial spatial option is used in the construction of buildings resistant to seismological disasters and high-rise buildings of more than nine floors, as well as in other structures under ordinary conditions. This is the main developed building design system; it is rarely used in housing construction due to unreasonable economic high cost.
Frameless type of spatial solution is used in the construction of residential buildings, used for the design of skyscrapers up to 30 floors. The volumetric-block structural system of buildings consists of load-bearing elements composed of self-supporting volumetric blocks placed on one another. The so-called pillars work in conjunction, thanks to a strong connection between each other with the help of rigid go flexible connected elements.
Frame-and-diaphragm construction solution
The system refers to combined schemes with an incomplete frame and is based on the distribution of the functions of stationary equilibrium between rod and wall bearing products. The structural systems of high-rise buildings are based on the principle of transferring horizontal loads to vertical wall diaphragms, and the vertical forces acting in the frame act on the bar elements. This method is used to erect the majority of high-rise panel-frame buildings of a residential type in ordinary construction conditions and in seismological hazardous areas.
Frame-block spatial solution
It is based on the joint work of blocks and frame elements, and volumetric structures act as load-bearing or mounted elements. Using reinforced concrete blocks fill the space in the supporting frame lattice. The 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 framework scheme when choosing a project. Long elements are designed so that they do not infringe on the planning solution, while ceiling beams do not protrude on the surface in residential buildings. The transverse arrangement of the girders is typical for high-rise buildings with a regular cellular structure in the plan (hotels, hostels), while the step of the bearing crossbars alternates with walls and partitions. The longitudinal arrangement of long load-bearing beams is used in projects of residential buildings of apartment type.
Bezelless 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 frameless system is characterized by low reliability and high cost, it is used in the construction of monolithic and combined prefabricated buildings using the method of raising floors and sliding formwork.
Building Systems
This concept characterizes the constructive solution in the complex of technological solutions for the method of construction of the structure and the choice of material for the applied elements and assemblies. Constructive building 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 scheme
The system is based on the manual execution of masonry walls. Speaking about the industrial construction method, it should be noted that the construction of enclosing elements remains from the traditional scheme. All other details of the building, such as floors, stairs, walkways, columns and others, are borrowed in the industry from a prefabricated project, which elevates traditional construction to a high level of industry.
The traditional system has the advantage that the small size of wall stones allows you to build houses of various shapes, of any height. Brick walls are reliably operated for a long time, have a high fire resistance threshold, and the masonry does not require plastering. The disadvantages include the great complexity and dependence of strength characteristics on the technology of the manufacturer and the skill of a bricklayer.
Complete system
According to this scheme, house designs are carried out, the construction of which is based on the installation of large prefabricated elements (panels, blocks) made of brick, ceramics, reinforced concrete. Complete assembly facilities are built according to the systems:
- from large blocks;
- using panels;
- with a hinge of wall plates on the frame;
- from volume blocks;
- from cast concrete.
Large block construction system
These types of structural systems of buildings 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 sizes requires a small investment, with a variety of forms being erected.
Panel structures
According to this scheme, houses with a height of 14 to 30 floors are designed, respectively, in seismic areas and in ordinary conditions. The wall structure consists of separate panels installed one on top of the other without dressing the joints in cement mortar. Their stability is ensured by welding embedded parts, and during operation by a strong connection of bonds and joints. The use of the system reduces the complexity of up to 40%, the cost of construction up to 7%, reduces the total mass of the structure by 20-30%.
Frame-panel solution of the project
Buildings are being erected with a supporting frame made of metal or precast concrete and framed by 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 economic and technical terms.
Block-block construction
This construction method refers to industrial types and consists in the installation of spatial elements made of reinforced concrete weighing up to 25 tons, containing one room in the volume (kitchen, room, bathroom, etc.). The blocks are built without dressing the seams. This method allows to reduce the complexity by another 15% compared with the panel method. The production of large-panel blocks is 15% more expensive than panels. They build low-rise buildings in seismic areas and 16-storey buildings under normal conditions.
Monolithic construction systems
They are used for high-rise buildings. Structural systems of monolithic buildings include structures in which all the supporting elements and units are made using reinforced concrete. Combined prefabricated monolithic house schemes involve the collection of loads on the frame from prefabricated reinforced concrete elements. Monolithic buildings are designed without a frame device, and prefabricated monolithic structures are built with or without a frame.
Industrial methods in this area include construction using concreting in formwork:
- moving;
- volumetric interchangeable;
- shield large.
The construction of monolithic buildings on the frame is performed by the methods:
- lifting floors;
- floor views.
The monolithic system corresponds in strength to prefabricated types of buildings, it is widely used in areas where you can actively use local materials and not invest in the development of the production base.