When most people hear the expression "frame house", they represent a wooden building. However, there are buildings erected by frame-monolithic technology, which are based on concrete. The metal profile or reinforced concrete structures can be used during the work. The frame is sheathed with cement-bonded particleboards, and the walls themselves can be made of blocks or bricks. It is important to remember that such buildings require the installation of a stiffness diaphragm, the design features of which will be discussed below.
Appointment
Between the columns to the entire height of the frame buildings, vertical wall panels are installed. The latter in the upper part may have shelves for installing floor slabs.
These elements connect column panels to each other and to each other, while they provide spatial rigidity to the entire building. They should be in buildings in all directions in such a way that there is an intersection and T-shaped or L-shaped figures are formed. Their fastening with columns is carried out in height at least at three points. In this case, welding of embedded parts is used. Rigid diaphragms are most often installed on strip foundations, in some cases, the bases are monolithic plates.
Design
The diaphragms that are used to increase stiffness can have a different type of design, among them there are:
- two-shelf;
- single-shelf;
- solid;
- with doorways;
- compound
- with ventilation ducts.
In the latter case, we are talking about diaphragms, which are ventilation units. Panels for such diaphragms are made of concrete of class M-300, this applies to the lower floors of the building, while for the most recent, a solution of the M-200 brand is used.
Stiffness diaphragms can be made in different periods of the year. If work is carried out in the summer, then the concrete strength should be 70% of the design, while in the winter season this figure should reach 100%. The reinforcement of reinforced concrete prefabricated panels is made of lower and upper racks, as well as a reinforcing block, which has enlarged dimensions. If the height of the frame does not exceed 3 m, and the design of the diaphragm does not have door or other openings, then the frame can be lightened.
What else you need to know about the design features
Stiffness diaphragms may include perimeter reinforcing openings. In this case, the stress concentration in the corners should be taken into account. The main task in this case is the collection of stiffness pylons. It is important to carry out calculations of geometric parameters and check whether the strength corresponds to the characteristics. Existing forces in the structures should also be analyzed. Regardless of the structural features of the stiffness diaphragms, they are designed for central compression, as well as shear forces from horizontal and vertical loads. If openings are present, then the elements should be checked for the combined effect of voltage in the upper part of the wall.
Features of mounting diaphragms stiffness
Monolithic stiffness diaphragms must be in the span between the columns, they are connected to each other using a monolithic crossbar, it is mounted on the upper part of the diaphragm. The latter should extend along the entire height of the building, and in some cases it is possible that the elements are not installed on the technical floor.
The lower floor should be supported by a foundation grill with embedded parts. In order to ensure the stability of the building, the diaphragms are installed in both directions. Vertical should be placed according to plan evenly, they are combined with the elevator railings. The stiffness diaphragm in frame buildings should be installed in an amount of at least three in one temperature unit. The geometric axes of these elements must not intersect, the center of gravity must coincide with the center of gravity of the axis of the building.
In order to increase the spatial rigidity of a building, which has an increased number of storeys, it is necessary to provide measures to ensure the compatibility of the diaphragms with the frame. This can be achieved by a keyway device between the column and the diaphragm.
Installation Recommendations
In order for the wall to be as strong as possible, a stiffness diaphragm must be present in the building. If we are talking about the II-04 series, then in the upper corners of such products there should be clippings on which console columns will subsequently be placed. In addition, there are steel rod outlets in the corner of the diaphragm. To fix the diaphragm of this series, a closed loop is applied to the frame of steel rods, the diameter of the latter can vary from 12 to 28 mm. The rods are always welded, which guarantees additional structural strength.
A series of stiffness diaphragms may look like 1.020-1, in which case there are no corner trimmers on the elements. Such structures are reinforced with special vertical frames, and a steel mesh is fixed along the perimeter of the structure, the diameter of its rods can vary from 5 to 12 mm, while the cells have a size of 200 mm. The diaphragms of this series are installed parallel to the crossbars, and then replace these building elements.
Conclusion
Those diaphragms that are parallel to the crossbars are devoid of additional consoles. On the vertical faces of II-04 there are places with which structural frames will be connected to the columns. If you will use the diaphragm series 1.020-, then for it should be prepared embedded parts.
It is also worth mentioning that the diaphragms are called stiffness cores, and represent one of the main elements of buildings for any purpose. The task of this component is the perception of horizontal loads according to the type of seismic and wind loads that affect the building.