PRECAST CONCRETE - vikon-group.ruvikon-group.ru/data/files/downloads/wall_panels_application_eng.pdf · The group of companies VikON [email protected] External wall panels Airtightness

application and production of wall panelsPRECAST CONCRETE

The group of companies VikON www.vikon-group.ru [email protected]

External wall panels

Finishing

Basic requirements and joints for designing and manufacturing of external wall panels

Feasibility study of housing with application of wall panels

Wall panels manufacturing systems

The group of companies VikONwww.vikon-group.ru [email protected]


External wall panels – SW panels

«Sandwich» structure

Precast concrete wall panels have undergone con-siderable changes concerning production tech-nologies and architectural quality. These products consist of internal and external concrete slabs with insulation barrier made from mineral cotton wool or cellular polystyrene. The external concrete slab with or without post treatment is a face wall. Slabs are connected by means of acid-proof hinges, preventing displacements caused by an external slab, mainly, because of temperature differences. The internal slab usually has a thickness of 120-150mm; however these dimensions can be modi-fied for construction of high-rise buildings. insula-tion layer usually makes 100-200mm, depending on its functions. The thickness of external layer can vary, depending on an external layer of the fa-cade. Usually it makes 80mm.

Application

SW panels are used in various types of construc-tion, such as residential houses, offices, hotels, schools, public health establishments and commer-cial pavilions.

One of the reasons of such wide application of SW panels is that it meets most of the technical re-quirements established in relation to housing. it is a matter of such aspects, as bearing structure and constancy relative to airtightness, thermal insula-tion, water resistance, fasade design and industrial efficiency. Besides, level of factory readiness is also very high. After installation only internal painting and external connection are required.

That approach allows necessary level of airtight-ness and water resistance. Efficiency of all con-struction site also improves.

80...200

100, 120, 140, 150 mm

80 B 80 ... 180

A=270...410

Heat insulation

Internal layer

External layer

Single wall panel



Airtightness and water resistance

Build-in internal slab of SW panel forms an airtight layer on the face side. in the window frame sealant is used to forming a joint with the internal slab.

Thus, due to monolith action, the SW panel without additional expenses gains constructive airtightness. it also means that hermetic seal-ing will not deteriorate in due course. Thus, it is guaranteed, that there are no damages be-cause of the over humidity or fungi, and it saves expenses.

Concrete slabs possess rather high resistance to diffusion, interfering, thus, the moisture of wa-ter steam. High resistance means that only small water amount is absorbed into concrete. in this connection, in our climatological conditions the walls dry up quickly during winter time when the high pressure gradient of steam inside and outside takes place. As for a new wall, it can contain some moisture amount. Water evapo-rates rather easily through the internal slab and insulation. During cold seasons moisture can drop on the external slab. The external slab is constantly ventilated for drying, and the steam condensate on inside of the external slab evap-orates through or close to a horizontal joint.

Thermal insulation

For buildings which get warm up to the tempera-ture over 18°C degrees, the thermal protection lay-er usually makes 150-180mm. in the present-day buildings cold bridges are very insignificant.

The frame round the windows usually requires a small deepening for the internal plate, which be-come thicker at the cost of thermal insulation. As a result the cold bridge is formed, which depends on depth and desired position of a frame relative to the facade. When frame’s depth is 105mm the thickness of insulation usually makes about 60mm. At present the standard frames by depth of 170mm are used. Thus, occurrence of cold bridges is re-duced to the minimum. Windows are fastened by means of standard frame screws into the internal plate.

Sandwich panels are so solid that by means of bearer made of stainless steel, attached to the in-ternal plate it is possible to mount directly balcony structures. in this case the balcony is installed on the external slab of the panel. Cold bridges are formed inside the panel; however their influence is limited, since they are formed by isolated areas, and the thermal conductivity factor of stainless steel is twice less than the ordinary. insulation properties of the panels at the above-stated thickness of in-sulating layer and minimum cold bridges, holding the thickness of a wall at tolerance level.


Heat storage

Heavy structures keep warmly considerably better, rather than light-weight. For example, the ordinary concrete wall of a residential building keeps heat eight times more than plaster on a wooden frame. in two-room apartment concrete accumulates or gives approx. 12 kW/hour on each degree of tempera-ture rise or fall. Heat gain received from the sun, the equipment, people etc., it is profitably maintained, allowing energy to collect and be allocated within the limits of the 24 hour periods. The indispensable condition of correct use of the accumulated warmth in a building is the conscious control over heating and ventilation. in this case reduction of useful ca-pacity of heating system is possible. The radiators sizes can be considerably reduced, and in certain cases with preservation of the same level of comfort its utilization can be completely refused. Decrease in demanded capacity means application of low-

temperature systems for heating with high quality energy (exergy). Reduction of supplied power for heating and/or cooling enables reduction of power inputs in connection with absorption and emission of superfluous heat of heavy mass of the wall.

As a whole, such properties as airtightness and wa-ter resistance, thermal insulation and heat storage, establish good conditions for development of pas-sive buildings with a concrete frame.

Sound

The external sandwich panels are used mainly in the presence of redundant transport noise. Combina-tions in a wall panel of good standard windows and insulation are provided with conformity of acoustic classification for unprotected places with high levels of transport noise.


INSIDE

INSIDE

INSIDE

INSIDE

OUTSIDE

OUTSIDE

50dB 80dB 30dB

regular wall

regular wall

regular wall

concrete element

concrete element

concrete element



Facades

The visible front layer of the sandwich panel pro-poses variety of alternatives in application of the given method in different urban conditions.

The surface can be made of:

› concrete without the subsequent treatment with a surface, faced to the mould during production process. Concrete can have various pigments. in addition to it, depending on structure of the mould, a various appearance can be cast on the surface.

- concrete without post treatment with a surface outside from the mould. The surface then threat-en to processing with use of various methods, as for example, polishing or cladding;

- painted structure where the paint is cladded

into the fine or coarse texture. The colour granu-lar layer can be smoothed down;

- smooth concrete having various pigments;

- cladding in natural stone at factory;

- constructed in brickwork, polished marble or granite;

- various materials such as wood and glass can be applied to the external slab of panel on a construction site;

- thick plaster on a construction site for a special external slab with seams deficiency.

Facade elements form seams. Spaces between fasade elements are usually filled with paste for seam sealing.


Finishing


Finishing


Finishing



WALL ELEMENT

Common data and application area

1) three-layer thermo-insulated external wall elements, i.e. sandwich panels (hereinafter re-ferred to as SW panels), the bearing interior layer of which is fasten to non-bearing exterior layer by stainless steel anchor;2) single wall panels

Wall elements are subdivided into the following types:

1) load-bearing walls;2) non-bearing walls;3) bearing stiffening walls.

The approximate thickness of wall elements are 80..410mm.

The maximum overall dimensions of wall elements are 4000x11000mm and maximum weight is 10 tons. in order to avoid possible formation of cracks in the exterior layer caused by concrete shrink-age or temperature changes it is recommended to avoid designing of wall elements over 6m long or divide the exterior layer into smaller sections by false seams.

Wall elements are mainly used for the construc-tion of housing but also non-residential buildings. When using precast wall elements the rate of con-struction increases considerably, whereas it is pos-sible to manufacture the exterior wall elements of the building with an adequate heat retention, which is very important in terms of energy savings. Also, the building fasade with external elements made of SW panels doesn’t require any supplementary finishing.

it is also possible to install electric and communica-tion channels already at the factory.

The determining factors at the selections of the thickness of interior wall elements are sound insu-lation, fire resistance, and structural requirements, in some cases also load-bearing capacity. The most important requirement for SW panels is thermal transmittance.

Wall elements are usually reinforced by:

1) Bearing internal layer of sandwich panels is reinforced by welding mesh in two layers; 2) Non-bearing external layer is reinforced by welding mesh in one layer;3) Along perimeter of the panel and openings are reinforced by bars.

Wall panels reinforcement is also depends on whether both concrete layers are bearing.

Wall elements specifications

Table 1.Single non-bearing wall panels specifications

Table 2.Single bearing wall panels specifications

Table 3.Sandwich wall panels heat conduction



Materials

The following materials are used for the manufac-ture of wall elements:

1) normal concrete with aggregate class B20/25 for interior layer (specific density 25,0 kN/m3);

2) normal or special concrete with aggregate class B30/35 for external layer (specific density 25 kN/m3;

3) non-stressed rebar is used for reinforcement.

imflammable fiber-glass and mineral fiber are used for thermal insulation of the SW panels, which are supplied with ventilation channels in order to avoid the condensation of moisture inside the building. Basement wall elements are usually insulated with polystyrene foam.

Production and surface treatment

Generally wall panels are casted on previously heated tilting tables with opening sides or on cast-ing pallets round the carousel production line. Wood timber and plywood with different formwork systems are used as a shuttering.

Freshly-poured concrete is compacted by high-frequency vibration. By the time of dismantling the shuttering 50% of concrete compressive strength is achieved. Back side of wall elements is formed on a smooth casting plate. Visible face of precast con-crete wall is made manually by hand float, steel rubbing or any other floating equipment.

Concrete wall panels surface finishing:

1) exposed concrete surface

a) exposed aggregate surface;

b) fine exposed aggregate surface;

2) brushed surface;

3) crushed surface;

4) rolled surface.

By using different color crushed stones various color shades can be achieved on exposed concrete surface.

Transport and storage

Wall elements can be lifted and transported strictly vertically only using special lifting devices. Rack-type shelves are used to store the panels.

Attention*: it is not allowed to lean SW panels against bearing external layer.

Quality

Wall panels quality is secured by designing meth-ods and factory production control. Factory pro-duction controls comprises regular control of all current machinery and equipment, incoming ma-terials inspection, functional production process monitoring as well as finished products testing.

Production and building tolerance

Normal type of wall dimensional accuracy is ap-plied to:

- external wall panels;

- internal wall panels always.

Particular type of wall dimensional accuracy is ap-plied when appearance of a building makes indi-vidual high demands.

Table 1. Production and construction tolerance for SW and internal wall panels



Picture 1. Connection joint of two SW panels

Picture 2.Angle joint of SW panel

Picture 3. Connection joint of internal wall panels and ceiling slab

Picture 4.Connection joint of internal wall panels and ceiling slabs

Picture 5. Angle joint of two SW panels and internal wall panel

Picture 6. Connection joint of two SW panels and internal wall panel



Progress data of precast concrete frame erection with application of external wall panels (SW panel) as a case study of a custodial institution construction in Saint-Peters-burg (August 2008).

Progress data of precast concrete frame erection with application of external wall panels (SW panel) as a case study of an apartment house construction in Тоsno, Leningrad region (March 2009).

Cost of 1m2 during 01/03/2009 – 220 EURO

Cost of 1m2 during 01/09/2008 – 221 EURO

Apartment house

Apartment house

Apartment house

Custodial institution

# Description Total price, EUROFrame area, m2 7 593,84

1 Floor slabs 237 975,00

2 In-situ area 33 549,00

3 Steel 25 745,00

4 Staircases 24 480,00

5 Ventilating blocks 36 600,00

6 Embedded items 40 460,00

7 Double-wall panels H = 330mm 280 476,00

8 Single-wall panels H = 180mm 35 630,00

9 Single-wall panels H = 100mm 13 388,00 Total: 728 303,00

10 Other expenses 65 000,00Total: 793 303,00

11 Transport service 7% 55 531,00

12 Cost of contractor service (frame erection) 398 677,00

13 Project cost 41 766,00Total cost: 1 289 277,00

# Description Total price, EUROFrame area, m2 6 498,5

1 Main frame elements 460 235,00

2 In-situ area 19 937,00

3 Mineral wool board 6 150,00

4 Fine-aggregate concrete 49 225,00

5 Steel 68 063,00

6 Stiffening diaphragm 18 801,00

7 Staircases 18 294,00

8 Ventilating blocks 33 540,00

9 Hoistways 47 526,00

10 Walling 224 900,00

11 Sealing of panel joints 11 550,00Total: 497 986,00

12 Other expenses 10 000,00Total: 507 986,00

13 Transport service 5% 25 399,00

14 Cost of contractor service (frame erection) 388 593,00

13 Project cost 17 500,00Total cost: 939 478,00



Facades



Summary list on erection of 3-storey apartment house with total area 1180 m2

*Note:

Cost of contractor services on house assembly and designing makes approx. 90 000.00 US dollars. Cost of precast concrete products and other mate-rials is defined by the Customer taking into account the local construction market prices.


Wall panels production systems

Carousel production system

This system is recommended for average and large-scale production. Total capacity - 500-1000m2/per day. The main advantage - high level of auto-mation. The main disadvantage – high cost invest-ments. Carousel system offers many advantages relative to other production systems in the field of manpower utilization, expendable materials and quantity of precast products.

Production process is based on carousel longitu-dinal and cross-section conveyors working non-stop, effecting an interlocked sequencing, and the pallets are displaced on installation synchronously from one station to another along production line. At every station various production stages are car-ried out. Product quality control is coordinated and monitored by computer system.

Using a carousel production system it becomes

simple to manufacture wall panels, working in two shifts a day, in conditions with down noise level.

The useful production floor area varies from 85 to 110 х 24m, being based on wall panels sizes, quantity and quality of product surface post treat-ment.



Long line production system

This system is recommended for average and small-scale production. Total capacity - 150-600m2/per day. The most rational system as for the cost entry investments level and time to achieve a quick pay-back.

The system consists of a painted welded steel struc-ture with a polished smooth mould surface with opening sides. Demoulding of products is carried out by inсlining of all system by means of hydraulic jacks. This system allows manufacture easily wall panels of various width or to adjust sides at one width of the panel and it is rationally use all width of the mould surface.

The concrete spreader is controlled by an operator and casts granulated concrete mix into the mould. A pouring system batches the concrete mix uni-formly within the required product dimensions and at the necessary thickness, provides high quality, without noise due to its direct vibration.

Production area sizes are shown at the drawing aside 120x24m.

The useful production floor area varies from 50 to 150m.

A 50m long production line is enough for 150m2/ per day production output.

For 600m2/per day production output it is essen-tial to have at the very last two 100m long produc-tion lines.



Wall panels production on tilting tables

This system is recommended for average and small-scale production. Total capacity - 50-350m2/per day. The main advantages: low cost of the equip-ment. Do not require foundations and can be in-stalled directly on the plane surface. Can be com-pounded in all-in-one long production line up to 50m.


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PRECAST CONCRETE - vikon-group.ruvikon-group.ru/data/files/downloads/wall_panels_application_eng.pdf · The group of companies VikON [email protected] External wall panels Airtightness