The main structural elements of the building-horizontal (floors, coatings), vertical (walls, columns) and foundations, taken together, make up a single spatial system – the bearing frame of the building.
The main purpose of the bearing frame-the structural basis of the building-is to perceive the loads acting on the building, work on the efforts of these loads to ensure the necessary performance of structures throughout their life.
The structural system is an interconnected set of vertical and horizontal load-bearing structures of the building, which together provide its strength, rigidity and stability. Horizontal structures – ceiling and cover the building perceive attributable to their vertical and horizontal loads and impact, giving them a floor to the vertical load-bearing structures. The latter, in turn, transmit these loads and effects through the foundations to the Foundation. The choice of structural systems is one of the main issues to be solved in the design of buildings.
There are three main structural systems of buildings: frameless, frame and combined (with incomplete frame).
Frameless system (with load-bearing walls), provided by this project, is a rigid, stable box of interconnected external and internal walls and ceilings. Exterior and interior walls take the loads from the intermediate floors.
This type of building in turn, subdivided into buildings with longitudinal bearing walls (slabs lie across the building), with transverse bearing walls (slabs lie along the building) and cross-longitudinal and transverse bearing walls (floor slabs with dimensions in plan equal to the cell dimensions between the four walls, relying on the contour).
Frameless system is the main in the mass housing construction of houses of different storeys. The size of residential cells, the need for partitioning walls and partitions to ensure sound insulation of apartments and other features determine the technical feasibility and economic justification for the use of frameless buildings in the construction of dwellings, as well as those civil buildings, which are dominated by multi-cell planning structure (sanatoriums, hospitals, dormitories, etc.). In buildings with a longitudinal arrangement of load-bearing walls, the use of large-span ceilings (with a span of 9 and 12 m) leads to the support of floors only on the outer walls and the transition from traditional three - and four-wall systems to a double-wall system. This ensures a high freedom of design solutions for residential homes and businesses built-in system maintenance, and ease of upgrading and conversion of buildings.
Frame system. Bearing elements in such buildings are columns, crossbars and ceilings, and the role of enclosing elements is performed by external walls. There are four types of frame constructive system: with a transverse crossbars; with longitudinal girders; with bezrigelny frame in which the crossbars are missing and the floor slab or rely on the capitals of the columns, or directly to the column.
Frame system is the main in the construction of mass public buildings, it is used for the construction of high-rise buildings, as well as in cases where you need a room of considerable size, free from internal supports.
When choosing a structural system of frame buildings take into account space-planning requirements: it should not link the planning decisions. The crossbars of the frame should not intersect the plane of the ceiling, and should take place in their borders, etc. So the frame with a transverse girders are used mainly in buildings with regular layout structures (hotels, hostels, pensions, etc.), combining step of the transverse partitions and the step bearing structures. The frame with longitudinal arrangement of crossbars is used when designing public buildings of complex planning structure (schools, medical institutions, etc.).
Combined system (with incomplete frame). In such buildings, along with the inner row of columns, the load from the floor slabs is perceived by the outer walls. There are two types of structural systems: longitudinal and transverse arrangement of runs.
Incomplete frame is used in the case of external walls as carriers.