WO1997028322A1

WO1997028322A1 - Precast lightweight concrete housing construction system

Info

Publication number: WO1997028322A1
Application number: PCT/SI1997/000002
Authority: WO
Inventors: Ante Mihanovic
Original assignee: Damjanic, Frano
Priority date: 1996-02-02
Filing date: 1997-01-17
Publication date: 1997-08-07
Also published as: AU1460297A; HRP960052A2; HRP960052B1; SI9720003A; BA97261A

Abstract

The precast lightweight concrete system for housing construction is based on the principle of the rapid construction of small and medium houses with precast wall and ceiling elements made of lightweight concrete. Efficient precasting principles and finishings for the facades and ceiling are used. The system consists of: ceiling/roof beams (2), cornice edge block (4), roof supporter block (5), ridge block (6), eaves supporter block (7), columns and cornices (10), basic wall block (11 and 12), ceiling and wall filler block (13), wall edge block (14) and wall corner block (15), where all these elements make a geometrically compatible system. Single elements or parts of the system can be used separately from the whole system and can be combined with other precast even monolithic masonry systems. A great number of different construction methods are possible due to the simple form of the elements. Therefore, architects and engineers have greater, creative freedom in housing design.

Description

PRECAST LIGHTWEIGHT CONCRETE HOUSING CONSTRUCTION SYSTEM

Technical field

The technical field is very well defined according to IPC subgroups E 04 B 1/00 and E 04 B 2/00 which contain general structures such as walls, ceilings, floors; roofs and single elements.

Technical problem

This precast lightweight concrete housing construction system solves the following problems: quick and rational building, partial or complete precasting and a high level of rough work finishing. The adaptability of the system to different forms of small and medium houses by using a few types of precast elements contributes to rationality and has wide applicability.

State of the art

A general review of masonry structures shows that precast technology based on small precast elements has been known for a long time. In addition to the classical stone blocks and concrete and clay block technology, lightweight concrete block technology was developed at the end of the 19 century. At the beginning of the 20 th century (1907) The British Museum was built using lightweight concrete technology based on clinker concrete. In the mid 1930s, aerated concrete was introduced into Europe mainly in Sweden. After War World II the production and application of lightweight elements made of expanded clay, expanded shale, foamed slag, and pumice, expanded becoming lighter and automatically achieving better insulation properties especially the temperature insulation property. At the same time, compressive strength was similar or a bit lower than for normal weight concrete. Expanded polystyrene lightweight concrete, as a special type of lightweight concrete, was introduced into Germany in 1951. Ytong (Europe) and Leca (Germany) and the systems based on expanded clay such as Aglite and Gravelite (USA, UK), Solite (Canada) and Liapor (Sweden) are technical systems which solve the given techical problem in a similar way. The most similar solutions to this innovation are given by Ytong's ceiling system and Leca's wall masonry system. Ytong's ceiling structure is designed as a precast plate 60 cm wide, 10-30 cm thick with a span up to 6.5 m. The lightweight concrete plate is made of the Ytong material with a density ranging from 450 kg/m3 to 600 kg/m3, which is reinforced by welded wire fabric in the tensile zone and partly in the compressive zone. Reinforcement is protected against corrosion by a special protective coating. The plates are placed by a small crane. The concrete roof of Heathrow Airport, England, is an example of this system ( See Short A, W. Kinniburgh, Lightweight concrete, third edition. Applied Science Publishers Ltd., 1978).

Wall masonry structures in the Leca technology are solved by lightweight blocks. The wall block has a circular openings which form vertical and horizontal channels. Column and cornice reinforcement is placed in channels and filled by concrete or mortar. One method of fastening is presented by the patent paper DE4414540-A1 with priority 93At-001042.

Lightweight concrete as structural and isolation material is incorporated in the technical codes of all developed countries. A special treatment of these structures is proposed by "Eurocode 2: Design of concrete structures - Part 1 -4; General rules - Lightweight aggregate concrete with closed structures, ENV 1992-1-4:1994".

Essence of the innovation

Essence of the innovation is the application of the principle of high level reinforcing, which includes the principle of complete reinforcing of precast lightweight concrete elements in housing construction.

The priciple of complete reinforcing of lightweight concrete is applied to ceiling and roof beams. In this way compressive stress, tensile stress and shear stress are carried out by reinforcement. Thus the lightweight concrete becomes a secondary structural material which ensures protection against corrosion, temperature insulation, fire resistance and humidity protection. Efficient wall reinforement is realized by placing a sufficient number of reinforced columns and cornices in a new way.

Lightweight concrete is of low density which implies a reduction of the dead load and, hence, less reinforcement and execellent insulation and protective properties. This precast system insures quick, efficient and low cost assembly. Precast small elements have been used in the construction industry but this system offers a wider application since the same elements and types of cross sections can be used for ceilings, roofs, walls and floors structures. In addition to the efficient level of finishing of rough work, it also offers an efficient level o1 facade finishing.

Description of diawings

This new precast lightweight concrete system is shown in the drawings. The drawings show one of the possible ways of the system application and do not limit the patent claims.

Drawing 1 shows an axonometric part of house designed by the presented system,

Drawing 2 presents cross section throughout precast ceiling,

Drawing 3 presents longitudinal section of ceiling beam including its reinforcement,

Drawing 4 presents cornice edge block,

Drawing 5 presents roof supporting block,

Drawing 6 presents construction of ridge and ridge block,

Drawing 7 presents eaves block,

Drawing 8 shows wall layout and its reinforcement,

Drawing 9 shows cross section of wall and its reinforcement elements,

Drawing 10 presents one of the possible types of reinforcement for columns and cornices,

Drawing 11 shows the form of the basic wall block,

Drawing 12 shows cross section of basic wall block and facade finishing ,

Drawing 13 presents the form of filler block compatible with basic wall block and with ceiling beam, Drawing 14 presents the form of the wall edge block, Drawing 15 presents the form of the wall corner block, Drawing 16 presents a possible way of forming the door or window lintel.

Detailed description of the patent realization

The new system of precast lightweight concrete housing construction as shown on Drawing 1 , consists of: ceiling/roof beams (2), cornice edge blocks (4), roof supporter blocks (5), ridge block (6), eaves supporter block (7), columns and cornices (10), basic wall blocks (11) and (12), ceiling and wall filler blocks (13), wall edge block (14) and wall corner block (15).

Precast ceiling and ceiling/roof beams (2) are presented in Drawings 2 and 3. The beam has either I or H type cross section and is made of lightweight concrete with a recommended density ranging from 250 kg/m^o 1200 kg/m³, with a compressive strength of more than 0.1 MPa. The length, the height, rib depth and fiansh depth of the beam (2) are chosen according to structural and insulation calculations. The recommended beam (2) span ranges from 3-12 m, the recommended beam height ranges from 0.12-0.35 m and the recommended rib and fiansh thicknesses are from 0.02 - 0.07 m.

The ceiling beam (2) consists of: reinforcement of the lower zone (2.1), reinforcement of the upper zone (2.2), shear reinforcement (2.3), fiansh reinforcement (2.4) (which is not obligatory), efficient ceiling finishing (2.5), adequate various liquid fillers (2.6), and anchoring reinforcement (2.7) of ceiling in the cornice, ( not obligatory).

Reinforcement is spliced and connected by welding and, if necessary, protected against corrosion by coating. The beam is partially bored at the top and bottom (2.8) to ensure space for placing perpendicular reinforcement ties, which are not obligatory. The upper (2.2) and lower reinforcement (2.3) which contain one or more reinforcing bars, form together with the rib reinforcement an internal truss of V, X or N type, where the rib reinforcement can be applied to at least one vertical plane.

The cornice edge block (4) which is shown in Drawing 4 as one of ϊhe possible types, is used as a lost element of the cornice ceiling structure. Its geometrical form is conditioned by the ceiling height and dimensions of the wall block. The height of cornice edge block coincides with the height of the ceiling beam, and the length coincides with the length of the basic wall block. Its width is designed so as to ensure maximum volume of the ceiling cornice concrete body. The feet of cornice edge block (4.1) which are not obligatory, insure better stabilization. The facade finishing of the cornice edge block (4.2), is identical to the basic wall block (11.1).

The roof supporting block (5) which is shown in Drawing 5 in the axonometric position, as one of the possible forms, is used to support the roof beam and is, at the same time lost form of roof cornice. The feet of the roof supporting block serve as bearings for roof beams and is the lower side of the roof cornice. The height of supporting block is up to 150% of the height of basic wall block. The length and width of the roof supporting block correspond to the dimensions of the basic wall block. The facade finishing of the roof supporting block (5.1 ), is identical to the basic wall block (11.1).

The ridge block (6) which is shown in Drawing 6, as one of the possible types, is used to connect the roof beams in the ridge. Its position to the roof beams can be fixed with the help of lateral wings (6.1). The row of ridge blocks hold the form for placing the ridge cornice (6.3).

The eaves supporting block (7) which is shown in Drawing 7, as one of the possible types, is used as an inserted element at the top of the wall which has eaves formed by roof beams. Its consists of a body (7), small wings (7.1) and anchors (7.2) in the cornice and anchors into the roof filler. Parts of the lower fiansh of the roof beam, which will be placed in the eaves supporting block, must be cut off.

One of the possible ways of wall constructions is shown in the layout to Drawing 8, and in the cross section in Drawing 9, and the column and cornice reinforcements in Drawing 10. The corner column reinforcements (10.1) are placed first followed by other column reinforcements (10.2) (Drawing 10). Then the first row of wall blocks are placed (11 ), (12). Their lower side is filled with half of the block filler (13) or an adequate cornice, which was previously cast (Drawing 9). Afterwards other rows are placed up to the level of the first cornice (10.3). Block filler (13) should be placed between rows of wall blocks. The upper sides of the wall blocks are coated by glue or mortar. Then wall edge blocks (14), corner wall blocks (15) and cornice reinforcements (10.2) should be placed. Afterwards column reinforcements which do not start from the foundations should be placed. After this phase, columns and cornices should be filled with mortar.

Lateral walls are connected to the main walls by half columns (10.4) (Drawing 8) and, if necessary, by horizontal ties through the wall block (10.5). The number of stories as well as number and position of columns and cornices are adapted to local conditions such as soil bearing capacity and earthquake and wind loads. Four - storey buildings are recommended in strong wind zones if there are no earthquakes, and two - storey buildings in strong earthquake zones.

One of the possible ways of ceiling and flat roof castings is shown in the Drawing 2. The ceiling beams (2) are placed on the leveled walls before placing cornice edge blocks. Afterwards ceiling fillers (13) are introduced, and if necessary, lateral anchors (2.8) can be also introduced. Then comes cornice edge blocks (4) and cornice reinforcement and, if necessary, longitudinal anchors (2.7) can be placed. Finally the ceiling and cornices are filled by special type of mortar or lightweight concrete.

The casting of sloped roofs is as follows: roof supporting blocks (5) and/or eaves supporting blocks (7) should be placed first, then a simple scaffold for supporting roof beams in the lateral direction must be prepared, subsequently a pair of roof beams (2) should be placed and connected by a ridge block (6). The following pair of roof beams are placed and if necessary roof filler (13) should be introduced, which must be done before placing the ridge block. Finally, the ridge cornice reinforcement is placed, and if necessary, anchors can be placed (2.6), and the roof structure is completed by filling it with special type of mortar. The ridge cornice (6.3) should be of lightweight concrete.

The ceiling or roof beams are precast in special metals or timber forms. If its reinforcement is protected against corrosion coating should be previously applied. The beam is cast in the reverse position, so the final layer of the lower side (2.5) can be placed. The basic wall block, cornice edge block, wall edge block and wall corner block are cast in special metal forms. The ceiling and roof block filler (13) is either made in special metal forms if it is made from lightweight concrete, or is cut out of expanded polystyrene blocks.

One of the possible types of lightweight concrete can be expanded polystyrene lightweight concrete. The ingredients and corresponding mixtures of expanded polystyrene lightweight concrete are shown in the following table.

INGREDIE EXPANDED ADMIX POLYPRO NTS CEMEN SAND WATER POLYSTYRENE TURE PYLENES

T (kg/ma) (l/ma) + (kg/ma) FIBBER (kg/ma) AERATED AIR or (kg/ms)

SIGN (l/ma) (l/ma)

EPSC-10 400-450 400-350 170-200 525 4 -

EPSC-8 350-450 250-150 170-200 600 5 -

EPSC-6 300-400 100-0 140-160 705 6 -

EPSCM-10 400-450 400-300 170-200 525 4 1-4

EPSCM-8 350-450 200-100 170-200 600 5 1-4

(table 1) The essential structural elements of this innovatory system, ceiling and roof beam or similar elements made of expanded polystyrene lightweight concrete if they are exposed to any kind of fire action must have a density greater than 800 kg/m³.

Manufacturing and application

The manufacture and application of this innovation system is evident. The system is applicable to new methods of housing construction, which is based on precast single elements.

Claims

PATENT CLAIMS

1.) Precast lightweight concrete system for housing construction shown in Drawing 1 , characterized by the compatible system of elements: ceiling/roof beam (2), cornice edge block (4), roof supporter block (5), ridge block (6), eaves supporter block (7), columns and cornices (10), basic wall block (11) and (12), ceiling and wall filler block (13), wall edge block (14) and wall corner block (15).

2.) Precast lightweight concrete ceiling/roof beam (2) according to claim 1 , the length, the height, rib thickness and fiansh thickness which are defined according to structural and insulation calculations is characterized by the I and H cross section type, made of reinforce and lightweight concrete with the following properties: density from 250 kg/m³ -1500 kg/m³, compressive strength higher than 0.1 MPa.

3.) Precast lightweight concrete ceiling/roof beam (2) according to claims 1-2, characterized by the lower zone reinforcement (2.1), upper zone reinforcement (2.2), shear reinforcement (2.3), fiansh reinforcement (2.4), which is not obligatory, efficient ceiling finishing (2.5), adequate various liquid fillers (2.6), anchoring reinforcement (2.7) of ceiling in the cornice, which is not obligatory.

4.) Precast lightweight concrete ceiling/roof beam (2) according to claims 1-3, where reinforcement is spliced and connected by welding and, if necessary, protected against corrosion by coatings, characterized by occasional openings at the top and bottom (2.8) ensuring space for the build up of perpendicular reinforcement ties, which are not obligatory, upper reinforcement (2.2) and lower reinforcement (2.3) which contain one or more reinforcement bars, where together with the rib reinforcement forms an internal truss of V, X or N type, where the rib reinforcement can be applied to at least one vertical plane. 5.) The basic wall block according to claim 1 , characterized by the H form of the cross section made of lightweight concrete of density ranging from 250 kg/m³- 1500 kg/m³ and compressive strength higher than 0.

5 MPa, insures filling with wall filler block (13).

6.) The basic wall block according to claim 5, characterized by the opening in the middle of the body (11.2), notches on the edges (11.3), and, if necessary, facade finishing (11.1), and covering the upper sides of block ribs with glue or mortar during construction.

7.)The ceiling or/and wall filler block according to claim 1 , characterized by the fact that it fills in the spacees between ceiling and roof beams (2) or/and between the basic wall blocks (11) in such a way so that the openings (11.2) and (11.3) are eft uncovred.

8.) The ceiling or/and wall filler block according to claims 1 and 7, characterized by the body made of super light material like expanded polystyrene, polyurethane or lightweight concrete with density lower than 900 kg/m³.