Reinforced concrete exterior wall panels are most often made in a single-row cut, that is, one floor high and one or two rooms long, and in terms of design they are single-layer, two-layer and three-layer (Fig. 3.4 and 3.5). All wall panels are supplied with lifting loops and embedded parts for fastening one panel to another and for connections with other structural elements of buildings.
a) Single-layer reinforced concrete exterior wall panels
Such panels are made of lightweight structural heat-insulating concrete on porous aggregates or from autoclaved cellular concrete (Fig. 3.5). On the outside, single-layer panels are covered with a protective and finishing layer of cement mortar 20–25 mm or 50–70 mm thick, and on the inside with a finishing layer 10–15 mm thick, i.e. such panels can be conventionally called “single-layer”. The thickness of the outer protective and finishing layers is prescribed depending on the natural and climatic conditions of the construction area, and they are made from vapor-permeable decorative solutions or concretes or from ordinary solutions with subsequent painting. Finishing the outer facade layer can also be done with ceramic, glass tiles or thin sawn stone tiles or crushed stone materials.
Rice. 3.4. Exterior reinforced concrete one-, two- and three-layer wall panels:
a - single-layer; b - two-layer; c - three-layer; 1 - lightweight structural and heat-insulating concrete; 2 - outer protective and finishing layer; 3 - structural concrete; 4 - effective insulation
Rice. 3.5. Composite elements of cross sections of external reinforced concrete wall panels: a - with an outer protective and finishing layer; b - with outer protective-finishing and inner finishing layers; c - from cellular concrete; d - two-layer with an internal carrier layer; e - three-layer with rigid connections between concrete layers; e - three-layer with flexible connections between the layers; 1 - structural heat-insulating or cellular concrete; 2 - outer protective and finishing layer; 3 - internal finishing layer; 4 - outer and inner carrier layers; 5 - lightweight heat-insulating concrete; 6 - fittings; 7 and 8 - flexible connection elements made of anti-corrosion steel; 9 - effective insulation; δ - the thickness of the insulation layer
Single-layer panels are reinforced along the contour with a welded mesh frame, and above the window openings - with a welded spatial frame. To prevent the opening of cracks in the corners of the openings, cross rods or L-shaped grids are laid outside (Fig. 3.6).
Single-layer panels from autoclaved cellular concrete cannot be made in height for the entire storey wall and walls with linear tape cutting are made from them. The fittings of such panels are protected from corrosion by coating with an anti-corrosion compound.
Rice. 3.6. Scheme of reinforcement of a single-layer lightweight concrete panel of the outer wall:
1 - jumper frame; 2 - lifting loop; 3 - reinforcing cage; 4 - L-shaped reinforcing mesh in the facade layer
Due to the high vapor permeability of lightweight concrete and, in connection with this, the possibility of water vapor condensation inside single-layer panels and its freezing at low outdoor temperatures, it is advisable to use such panels for buildings with low relative humidity of indoor air (no more than 60%). The thickness of single-layer panels is 240–320 mm, but not more than 400 mm.
b) Two-layer reinforced concrete exterior wall panels
Two-layer wall panels consist of an inner bearing layer made of heavy or lightweight structural concrete and an outer insulating layer of structural and heat-insulating lightweight concrete. The thickness of the inner carrier layer is at least 100 mm, and the thickness of the outer insulating layer is determined by the calculation for thermal protection. Outside, two-layer wall panels have a protective and finishing layer of cement mortar 20–25 mm thick with the same finish as in single-layer panels.
Since the internal load-bearing layer of dense concrete in two-layer panels has low vapor permeability, such panels can be used in buildings with high relative humidity of the indoor air. Reinforcement of two-layer wall panels is performed similarly to single-layer panels, i.e., the reinforcement cage is placed in the bearing and insulating concrete layers, but the working reinforcement of the lintels is placed in the bearing concrete layer. The total thickness of two-layer wall panels is not more than 400 mm (Figure 3.7).
c) Three-layer reinforced concrete outer wall panels
Three-layer external wall panels consist of inner and outer layers made of heavy or dense lightweight structural concrete, between which an insulating layer of effective heat-insulating material is laid. The thickness of the insulating layer is determined by the calculation for thermal protection, and the thicknesses of the inner and outer concrete layers depend on the design of the wall panel and the magnitude of the perceived loads.
The inner layer of the panels is reinforced with a spatial frame, and the outer layer is reinforced with a reinforcing mesh. Depending on the design, three-layer wall panels come with flexible or rigid connections between the inner and outer concrete layers (Fig. 3.5 and 3.8). Flexible connections are metal rods in the form of vertical suspensions and horizontal struts connecting the reinforcing cage of the inner layer and the reinforcing mesh of the outer layer of the wall panel, i.e. they are fixed by welding or tied to the spatial reinforcing cage of the inner layer and the reinforcing mesh of the outer layer. Metal rods of flexible connections are made of corrosion-resistant steel or they have an anti-corrosion coating in the insulation zone.
Flexible links ensure independent operation of the concrete layers of the wall panel and exclude thermal forces between the layers. The outer layer in panels with flexible connections performs enclosing functions and its thickness must be at least 50 mm. The thickness of the inner layer in three-layer panels with flexible connections in load-bearing and self-supporting wall panels is at least 80 mm, and in non-bearing panels - at least 65 mm.
Fig 3.7. Two-layer concrete panel of the outer wall: 1 and 2 - embedded parts for fixing heating radiators; 3 - lifting loops; 4 - reinforcing cage; 5 - inner carrier layer; 6 - outer protective and finishing layer; 7 - drain; 8 - window sill; 9 - lightweight concrete heat-insulating layer; H- floor height; AT– panel length; h– panel thickness; δ – thickness of the heat-insulating layer
In three-layer wall panels with rigid links, the inner and outer concrete layers are connected using vertical and horizontal reinforced concrete ribs. Rigid links ensure the joint static work of the concrete layers of the wall panels and protect the connecting reinforcing bars from corrosion. Connecting reinforcing bars are placed in concrete bracing ribs and they are attached by welding or tied to the reinforcing cage of the inner layer and the reinforcing mesh of the outer layer.
The disadvantage of rigid connections in the outer wall panels is through heat-conducting inclusions formed by the ribs, which can lead to condensation on the inner surface of the walls. To reduce the effect of thermal conductivity of the ribs on the temperature of the inner surface of the walls, they are made with a thickness of no more than 40 mm and preferably from lightweight concrete, and the inner concrete layer is thickened to 80–120 mm. The thickness of the outer layer is at least 50 mm. Exterior finishing of three-layer wall panels is carried out in the same way as one- and two-layer ones. In all panels of external walls, embedded parts for fastening to other structural elements are placed in the carrier layer.
Rice. 3.8. Three-layer concrete panels of external walls and connections of their concrete layers:
a – arrangement of flexible links; b - the same rigid connections: 1 - suspension; 2 - spacer; 3 - brace; 4 - rib made of concrete of the outer layers; 5 - light concrete rib; 6 - inner concrete layer; 7 - outer concrete layer; 8 - reinforcing cage of the inner layer; 9 - reinforcing mesh of the outer layer; 10 - rib reinforcement; 11 - effective insulation
Fully complying with the requirements of standards, technology and GOST for multi-storey buildings, we have added a number of improvements related to freer layouts, increased heat savings, appearance, quality of production and installation of panels, so that your home has the best performance modern private house.
EXTERIOR WALL PANELS
Reinforced concrete panels for building a house (External three-layer reinforced concrete wall panels) are made according to individual design drawings, in accordance with the requirements of the current GOST 31310-2015 "Three-layer reinforced concrete wall panels with effective insulation." High-rise multi-storey panel houses are built from the same panels.
Three-layer reinforced concrete panel consists of three layers:
External protective and decorative reinforced concrete layer 70 mm thick.
The middle layer of effective insulation with a thickness of 200-400 mm.
Internal bearing reinforced concrete layer 120 mm thick.
The inner and outer reinforced concrete layers are made of heavy concrete class B25 on crushed granite and steel reinforcement class A500C. Depending on the design calculations, a double mesh of reinforcement is laid in the inner layer and a single mesh in the outer layer.
The outer and inner reinforced concrete layers are connected to each other using rigid diagonal ties made of PD and PPA stainless steel from the Finnish manufacturer Peikko Group.
The thickness of the middle layer of insulation is determined thermotechnical calculation and can be up to 400 mm. In the basic configuration of houses from the INPANS company, the insulation in the panels has a thickness of 200 mm. With an EPPS insulation thickness of 200 mm, the heat transfer resistance coefficient of the wall is 5.97 (m².˚C)/W, which is 2 times higher than the Russian requirements for heat saving and meets more stringent European standards.
As a heater, we use materials that have the appropriate certificates, confirming their safety and service life in three-layer reinforced concrete panels for at least 50 years:
Extruded polystyrene foam (EPS). This insulation has one of the lowest thermal conductivity among other similar products. It is characterized by chemical resistance, high compressive strength, water and steam impermeability, as well as resistance to mold and mildew. Thus, extruded polystyrene foam not only provides thermal insulation, but also effectively prevents the impact of a number of other destructive and negative factors.
Stone wool. For three-layer reinforced concrete panels, we use specially designed high-strength stone wool with vertical and horizontal grooves that form a ventilation gap for ventilation of the insulation and removal of the resulting condensate. Stone wool is a non-combustible material, and the thermal conductivity index stone wool 20% lower than EPS.
*In agreement with the Customer, other types of insulation can be used.
In a three-layer design reinforced concrete wall, any insulation is reliably protected by the outer reinforced concrete layer from possible negative effects on it from environment(UV radiation, precipitation, and others), and the inner reinforced concrete layer does not allow the constituent substances of the insulation to penetrate into your home. In addition, the inner reinforced concrete layer will protect the insulation from the consequences of a possible fire.
MANUFACTURE OF WALL PANELS
For the production of reinforced concrete wall panels for the construction of a private house, as well as for multi-storey buildings, modern expensive equipment is required, which only large reinforced concrete factories have. Since 2014, the INPANS company has been successfully cooperating with the SiB-center reinforced concrete plant located near St. Petersburg, which is one of the most modernly equipped enterprises in its industry, producing over 250 types of precast concrete products and structures for industrial and civil construction . Also, we have agreements on the production of wall panels with factories located in Moscow, Nizhny Novgorod, Kostroma, Novocheboksarsk.
Concrete concrete plant "SiB-center", in particular, has at its disposal six molding tables / pallets measuring 4.25x16.5 m with vibration compaction systems and lifting at an angle of up to 80 degrees, equipped with magnetic side equipment, which are the basis for the production of three-layer and single-layer wall panels .
Wall panel production equipment makes it possible to produce wall panels with any individual characteristics (external dimensions, thickness, dimensions of window and door openings) up to 16 meters long and up to 4 meters high, however, it is usually very expensive to deliver such an oversized cargo to the construction site, and often not possible at all. Therefore, in order to meet the requirements for standard cargo transportation, we manufacture panels maximum height 3.32 m (floor height 3.1 m) and maximum length 7.8 m.
In most cases, such maximum dimensions are sufficient to implement any house project and minimize the number of interpanel seams, and panel joints should be made in alignment with load-bearing internal walls and / or partitions.
Window and door openings are laid on the basis of the project, their dimensions can be of almost any width and height, in addition, it is possible to make arched openings, round or any other shape.
For installation of windows and doors in window and doorways between reinforced concrete layers is installed wooden plank 50 mm thick over the entire width of the insulation, with the help of fasteners, the board is securely monolithic.
Also, in the outer reinforced concrete layer in the window openings, so-called "quarters" are formed for better installation of windows.
FACADE SOLUTIONS
Taking into account all the results of many years of accumulated experience in the design, construction and operation of large-panel multi-storey buildings, as well as the possibility of using modern materials and approaches to the manufacture of wall panels, the company "INPANS" has tested and is ready to offer you a number of reliable and inexpensive solutions to make the facade of your house expressiveness and individuality:
Forming the outer surface. Before pouring concrete mix special sheets-matrices imitating various facade materials are placed on the forming table. After pouring and hardening of the concrete mixture, an imprint remains on the outer surface of the panel that exactly repeats not only the contour, but also the texture, for example, brick, stone, wooden beam. Matrix sheets can be made for almost any material. The concrete surface molded in this way will not be erased over time and will always remain unchanged.
To create this texture, during the production process, the outer surface of the panel is applied special compound, which prevents the hardening of a small layer of concrete 3-5 mm deep. After solidification of the main mass of concrete and raising the panel to a vertical position, the uncured layer is washed off by the pressure of water and the crushed granite present in the concrete mixture appears on the surface. The facade turns out, as it were, sprinkled with small granite pebbles. This solution does not require staining.
Scratched concrete. This texture is created by passing over the surface of only set concrete with special hard brushes. The brushes leave groove marks on the concrete surface, creating the effect of “scratched concrete”. Grooves can be pulled both vertically and horizontally.
Finishing with facade materials. At your request, outside surface also, it can be lined with any other facade materials (clinker brick, wooden planken, fiber cement siding, etc.).
Using these textures separately or combining them, you can implement almost any design solution on the facade of your house.
Most of the facade solutions are implemented in the process of manufacturing wall panels; the panels come to the site already with a finished finish.
INTERNAL BEARING PANELS
Internal load-bearing reinforced concrete wall panels are produced on the same equipment as three-layer external panels. They consist of one layer of B25 class heavy concrete and steel reinforcement. The thickness of the internal load-bearing panels, depending on the design solutions, ranges from 120 to 180 mm.
Openings in internal load-bearing walls, as well as in external ones, can be made rectangular, arched or of another shape.
The quality of the inner surface of the outer and internal panels smooth and does not require leveling plaster, it is enough to apply finishing putty, or, for example, in the bathroom, immediately glue the tiles. Tolerances for differences along the entire plane of the panel are not more than 3-5 mm.
In addition, unlike walls made of block materials such as brick, gas silicate and other blocks, the inner surface of reinforced concrete panels does not have technological seams and is homogeneous. Cracking is impossible on them, and when decorating walls, the use of a reinforcing mesh is not required.
The joints of the panels inside the house (panel joints) are sealed with concrete during their installation. Corner interpanel seams have a width of only 80-120 mm and are made in the plane of the walls. And we design and make interpanel seams of linear panels in the alignment of load-bearing walls or partitions in order to hide them.
In the manufacture of external and internal reinforced concrete panels, they can be embedded with strobes for electrical wiring and other technological holes according to your project. This greatly simplifies and speeds up the process of laying engineering communications.
For the possibility of a variety of planning solutions, the designers of the INPANS company try to make the minimum number of internal load-bearing walls, and in some solutions you can do without them at all. The main task of internal load-bearing walls is to serve as a support for floor slabs.
FLOOR PLATES
We use proven and reliable multi-hollow floor slabs of the PB and PK brands as interfloor floors. Thanks to modern equipment, PB slabs can be made of any length, while floor slabs with a thickness of 220 mm can cover a span of up to 7 meters, and slabs with a thickness of 265 mm can cover a span of up to 10 meters. The standard floor slab width is 1.2 m.
In addition to the standard width, PB slabs can be cut lengthwise into additional slabs (290, 470, 650, 830, 1010 mm in size). In addition, PB slabs can be cut diagonally without loss of bearing capacity.
If necessary, make a balcony slab, a slab with cantilever support or with non-standard holes (for example, for chimneys large diameter) such slabs are made completely monolithic, by analogy with internal load-bearing walls, according to the relevant drawings with the reinforcement necessary for each specific case.
For large openings in floors hollow core slabs(for example, for a stairwell or installation of ventilation shafts) we use standard PETRA® steel brackets from the Finnish manufacturer Peikko Group, which allow you to open an opening up to 2.4 meters wide (width of 2 standard plates overlaps).
The variability of modern floor slabs allows you to perform any space-planning solution for the design of your house, and their installation takes only a few hours.
DELIVERY AND INSTALLATION OF WALL PANELS
Wall panels are delivered from the factory by panel trucks, a standard panel truck can bring panels with a total length of 2X7.8 meters and a total weight of not more than 20 tons. As a rule, wall panels for two-story house 10x10 meters are delivered by 10 flights of standard panel carriers. As a rule, delivery and installation of wall panels is made in one day.
Important! It is necessary to have or arrange an access road for panel carriers and a platform for a truck crane to the construction site.
Installation of wall panels on the foundation is carried out by a truck crane, which is located between the foundation and panel carriers. The truck crane removes the wall panels from the panel carrier and immediately sets them in the design position on the foundation. The process of installing one panel on average takes 15-20 minutes. And all wall panels of one floor are mounted within one or two days, depending on their number.
Important! The choice of a truck crane is based on the weight of the wall panels and the distance that the panel needs to be moved. In our practice, we have used cranes with a lifting capacity of 25 to 120 tons.
Wall panels are mounted in the design position, previously marked on the foundation, on the underlying mortar layer and fixed on temporary supports (struts):
Immediately after the installation of the wall panels, floor slabs are laid on them, the gaps between the floor slabs are reinforced:
The wall panels are connected to each other by embedding the joints of the inner bearing layer with heavy concrete. To connect the wall panels to each other, steel cable loops from the Finnish manufacturer Peikko Group are laid at the horizontal ends of the carrier layer with a step of 400-500 mm. When wall panels are installed side by side, the cable loops of adjacent panels intersect, forming a node into which the reinforcement is inserted.
With this technology of joining the inner reinforced concrete layer of wall panels, the interpanel seam becomes airtight, it does not let wind or moisture from the street through.
After setting concrete in monolithic sections, temporary supports (struts) are removed and you can proceed with the installation of panels of the next floor.
This wall panel installation technology is also used in the construction of modern multi-storey prefabricated buildings, and is rightfully considered the most advanced in the industry.
Wall panels practically do not shrink, and to interior decoration You can start immediately after the completion of construction and installation work.
PANEL JOINTS
After embedding, the internal bearing reinforced concrete layer completely excludes the penetration of moisture and wind into the house from the street, a strip of mineral wool or this place is being filled mounting foam. Then, a foamed polyethylene bundle is inserted into the alignment of the outer reinforced concrete layer and a sealant for interpanel joints is applied on top, which can be painted in the color of the facade. Unlike multi-storey buildings, for our houses we make seams only 20-25 mm wide.
To hide the interpanel seams outside the house, they can simply be painted in the same color as the facade, or covered, for example, with corner clinker or fiber cement tiles, or other materials can be used.
INTERIOR PARTITIONS
Non load bearing internal walls(partitions) can be made of any materials you wish. The company "INPANS" offers to make partitions from moisture-resistant full-bodied tongue-and-groove slabs (GWP). Partitions can be made of single-layered 80 or 100 mm thick PGP, as well as multi-layered with a layer of mineral wool between two partitions to increase sound insulation between rooms.
Installation time internal partitions is 1-2 weeks, and is carried out simultaneously with the installation of the attic floor and roof.
ATTIC FLOOR
If you have a cold attic in your house, attic floor performed according to wooden beams with a step of 600 mm, between which a layer of insulation (mineral wool) 200 mm thick is laid, then another layer of mineral wool 100 mm thick is laid crosswise on top of the ceiling.
Thus, the total thickness of the insulation is 300 mm, such insulation is included in the basic package of our houses.
From below, the overlap is hemmed with a vapor barrier film to prevent moisture from entering the insulation from inside the room.
PITCHED ROOF
The pitched roof is carried out along wooden rafters, then a wind-moisture protective membrane, a crate and a counter-crate are attached. Depending on your wishes and architectural solutions, a finishing coating is arranged. The most common are metal or soft shingles.
When choosing roof finish materials, we recommend using only quality materials with validated manufacturer's warranty.
FLAT ROOF
The device of a flat roof is made according to reinforced concrete slabs ceilings, with the installation of reinforced concrete parapets around the entire perimeter of the house. The ceiling is insulated with extruded polystyrene foam, a slope is made, the lower layer of waterproofing and a double layer of upper waterproofing. Drainage funnels, ventilation and chimney ducts are also arranged.
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Modern three-layer wall panels with PIR insulation, manufactured under the KROHN brand, are also intended for the construction of walls at various facilities. Due to the presence of high-quality insulation inside the panel, this building material has excellent thermal insulation characteristics. But no less important advantage is the ease of assembling an object from sandwich panels.
Three-layer wall panels with PIR insulation
The KRON group of companies sells PIR wall sandwich panels in Moscow. They can be of different thickness (from 30 to 220 mm), have different type profile (beading, stripes, microprofiling, without ribs) and any color according to the RAL scale.
To ensure perfect butt joints during the installation of three-layer wall panels with insulation, a reliable tongue-and-groove lock or a double-thorn-groove labyrinth connection is used during the production process. Due to this, the stability of the structure is increased and the possibility of the formation of "cold bridges" is excluded.
Benefits of sandwich panel construction
Technical characteristics of KROHN PIR sandwich panels:
Reinforced concrete exterior wall panels are most often made in a single-row cut, that is, one floor high and one or two rooms long, and in terms of design they are single-layer, two-layer and three-layer (Fig. 3.4 and 3.5). All wall panels are supplied with lifting loops and embedded parts for fastening one panel to another and for connections with other structural elements of buildings.
a) Single-layer reinforced concrete exterior wall panels
Such panels are made of lightweight structural heat-insulating concrete on porous aggregates or from autoclaved cellular concrete (Fig. 3.5). On the outside, single-layer panels are covered with a protective and finishing layer of cement mortar 20–25 mm or 50–70 mm thick, and on the inside with a finishing layer 10–15 mm thick, i.e. such panels can be conventionally called “single-layer”. The thickness of the outer protective and finishing layers is prescribed depending on the natural and climatic conditions of the construction area, and they are made from vapor-permeable decorative solutions or concretes or from ordinary solutions with subsequent painting. Finishing the outer facade layer can also be done with ceramic, glass tiles or thin sawn stone tiles or crushed stone materials.
Rice. 3.4. Exterior reinforced concrete one-, two- and three-layer wall panels:
a - single-layer; b - two-layer; c - three-layer; 1 - lightweight structural and heat-insulating concrete; 2 - outer protective and finishing layer; 3 - structural concrete; 4 - effective insulation
Rice. 3.5. Components of cross-sections of external reinforced concrete wall panels: a - with an external protective and finishing layer; b - with outer protective-finishing and inner finishing layers; c - from cellular concrete; d - two-layer with an internal carrier layer; e - three-layer with rigid connections between concrete layers; e - three-layer with flexible connections between the layers; 1 - structural heat-insulating or cellular concrete; 2 - outer protective and finishing layer; 3 - internal finishing layer; 4 - outer and inner carrier layers; 5 - lightweight heat-insulating concrete; 6 - fittings; 7 and 8 - flexible connection elements made of anti-corrosion steel; 9 - effective insulation; δ - the thickness of the insulation layer
Single-layer panels are reinforced along the contour with a welded mesh frame, and above the window openings - with a welded spatial frame. To prevent the opening of cracks in the corners of the openings, cross rods or L-shaped grids are laid outside (Fig. 3.6).
Single-layer panels from autoclaved cellular concrete cannot be made in height for the entire storey wall and walls with linear tape cutting are made from them. The fittings of such panels are protected from corrosion by coating with an anti-corrosion compound.
Rice. 3.6. Scheme of reinforcement of a single-layer lightweight concrete panel of the outer wall:
1 - jumper frame; 2 - lifting loop; 3 - reinforcing cage; 4 - L-shaped reinforcing mesh in the facade layer
Due to the high vapor permeability of lightweight concrete and, in connection with this, the possibility of water vapor condensation inside single-layer panels and its freezing at low outdoor temperatures, it is advisable to use such panels for buildings with low relative humidity of indoor air (no more than 60%). The thickness of single-layer panels is 240–320 mm, but not more than 400 mm.
b) Two-layer reinforced concrete exterior wall panels
Two-layer wall panels consist of an inner bearing layer made of heavy or lightweight structural concrete and an outer insulating layer of structural and heat-insulating lightweight concrete. The thickness of the inner carrier layer is at least 100 mm, and the thickness of the outer insulating layer is determined by the calculation for thermal protection. Outside, two-layer wall panels have a protective and finishing layer of cement mortar 20–25 mm thick with the same finish as in single-layer panels.
Since the internal load-bearing layer of dense concrete in two-layer panels has low vapor permeability, such panels can be used in buildings with high relative humidity of the indoor air. Reinforcement of two-layer wall panels is performed similarly to single-layer panels, i.e., the reinforcement cage is placed in the bearing and insulating concrete layers, but the working reinforcement of the lintels is placed in the bearing concrete layer. The total thickness of two-layer wall panels is not more than 400 mm (Figure 3.7).
c) Three-layer reinforced concrete outer wall panels
Three-layer external wall panels consist of inner and outer layers made of heavy or dense lightweight structural concrete, between which an insulating layer of effective heat-insulating material is laid. The thickness of the insulating layer is determined by the calculation for thermal protection, and the thicknesses of the inner and outer concrete layers depend on the design of the wall panel and the magnitude of the perceived loads.
The inner layer of the panels is reinforced with a spatial frame, and the outer layer is reinforced with a reinforcing mesh. Depending on the design, three-layer wall panels come with flexible or rigid connections between the inner and outer concrete layers (Fig. 3.5 and 3.8). Flexible connections are metal rods in the form of vertical suspensions and horizontal struts connecting the reinforcing cage of the inner layer and the reinforcing mesh of the outer layer of the wall panel, i.e. they are fixed by welding or tied to the spatial reinforcing cage of the inner layer and the reinforcing mesh of the outer layer. Metal rods of flexible connections are made of corrosion-resistant steel or they have an anti-corrosion coating in the insulation zone.
Flexible links ensure independent operation of the concrete layers of the wall panel and exclude thermal forces between the layers. The outer layer in panels with flexible connections performs enclosing functions and its thickness must be at least 50 mm. The thickness of the inner layer in three-layer panels with flexible connections in load-bearing and self-supporting wall panels is at least 80 mm, and in non-bearing panels - at least 65 mm.
Fig 3.7. Two-layer concrete panel of the outer wall: 1 and 2 - embedded parts for fixing heating radiators; 3 - lifting loops; 4 - reinforcing cage; 5 - inner carrier layer; 6 - outer protective and finishing layer; 7 - drain; 8 - window sill; 9 - lightweight concrete heat-insulating layer; H- floor height; AT– panel length; h– panel thickness; δ – thickness of the heat-insulating layer
In three-layer wall panels with rigid links, the inner and outer concrete layers are connected using vertical and horizontal reinforced concrete ribs. Rigid links ensure the joint static work of the concrete layers of the wall panels and protect the connecting reinforcing bars from corrosion. Connecting reinforcing bars are placed in concrete bracing ribs and they are attached by welding or tied to the reinforcing cage of the inner layer and the reinforcing mesh of the outer layer.
The disadvantage of rigid connections in the outer wall panels is through heat-conducting inclusions formed by the ribs, which can lead to condensation on the inner surface of the walls. To reduce the effect of thermal conductivity of the ribs on the temperature of the inner surface of the walls, they are made with a thickness of no more than 40 mm and preferably from lightweight concrete, and the inner concrete layer is thickened to 80–120 mm. The thickness of the outer layer is at least 50 mm. Exterior finishing of three-layer wall panels is carried out in the same way as one- and two-layer ones. In all panels of external walls, embedded parts for fastening to other structural elements are placed in the carrier layer.
Rice. 3.8. Three-layer concrete panels of external walls and connections of their concrete layers:
a – arrangement of flexible links; b - the same rigid connections: 1 - suspension; 2 - spacer; 3 - brace; 4 - rib made of concrete of the outer layers; 5 - light concrete rib; 6 - inner concrete layer; 7 - outer concrete layer; 8 - reinforcing cage of the inner layer; 9 - reinforcing mesh of the outer layer; 10 - rib reinforcement; 11 - effective insulation
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