FLOOR STRUCTURE

Abstract: The invention describes a technology to build floors that can span over large bays at low cost. The floor contains steel case profiles (1) that are self-supporting in the construction state and is in the service state a composite structure with a capacity to bear great loads, even running loads. The floor allows for extensive installation without the need for a false ceiling, it has a smooth and ready-painted underside and a smooth top surface, ready to finish by possible wearing surfaces (9). The floor is suitable for sleeper walls, intermediate floors and roofs, and even for decks with traffic.

Description: FLOOR STRUCTURE Technical Field, State of the Art A building, used as an office, industrial plant, or occasionally as a residential building, is generally made of in situ poured concrete or is alternatively constructed with a frame of columns and beams or wall slabs made of concrete or steel or sometimes timber The beams and/or the wall slabs bear in turn floor elements with additional jointing, reinforcement, and top casting or flow filling The elements are painted or covered by a false ceiling in order to obtain space for installations and improved sound comfort The most common type of floor element is the cellular floor unit, which can span over large bays at reasonable cost However, the weight of the units requires an expensive crane for the assembling, especially where the out-reach of the jib has to be great The in situ poured concrete frame is more time-consuming to build, is not economically capable of large spans, requires scaffolding and pulling down of the form-work, and involves extensive costs for cleaning and filling etc The in situ pouring, however, forms a rigid frame, which easily can be adapted to various requirements for installations and cantilevering floors and can be given good sound and fire protection properties In North America corrugated sheet is often used as dead mould for a poured concrete layer The free span is even smaller than for an ordinary in situ poured structure, and the system requires a beam grid, an additional false ceiling e t c As an other opportunity the sheet could be propped by ledgers, which is a nuisance especially where propping is required several storeys down the building The same situation applies to dead mould made of concrete, so-called filiform floor units A few years ago efforts were made to use case profiled steel sheet units filled with concrete These units needed also propping that left visible intrusions after the pulling down of the ledgers In order to save reinforcement 2 and to use the sheet as reinforcement in the finished structure the corrugated sheet is often shaped with irregularities, which at static loading clamp to the concrete and produce composite action between the sheet and the concrete. In most cases a false ceiling is required with these types of structures. During recent times also light floors have been developed, made of thin-walled steel joists in combination with plaster board, particle board or similar sheets in one or more layers at top and bottom. In order to obtain acceptable sound insulation these floors also contain mineral wool arranged in various ways. Today these floors can only span about 4.5 m, but tests with spans up to 7 m is under way. What these floors have in common is that they require a great amount of work and that there is a need for accuracy in execution of the work in order to avoid leaks. The load bearing capacity of all the above mentioned types of floors, except for the in situ poured structure, is restricted to static loading of the type and magnitude that is common in offices and residential buildings without large concentrated loads. In most cases a false ceiling is needed for the installations and to provide an acceptable environment. The aim and most important characteristics of the invention The aim of the invention is to provide an overall solution to the actual problem without said disadvantages. The invention is a further development of the technology described in SE, C2, 501 583 for bridges and similar structures, where steel case profiles, with at the top closely spaced cuts for reinforcement bars, by mechanical contact to the reinforcement bars perform in composite action with concrete poured in- and onto the profiles. Since space is left for a sufficient number of fasteners through the bottom of the case profile into the load bearing beam there is a possibility to obtain composite action with the beam, which increases its stiffness and load bearing capacity. With the invention the shape is further developed for buildings. Here is thin plate in the thickness range 1 to 3 mm used, which may be produced as plate strip on 3 coils with finished coating at low cost. Since composite action is obtained by mechanical contact at the cuts at the top of the case profile the concrete in the bottom of the case may be substituted by a light porous and sound insulating material such as haydite, aerated concrete or mineral wool. Since the cost for such a material is only a fraction of that of concrete, and since the floor is not intended for as great concentrated loads as those on a bridge, the case profile may be shaped deeper than in the above mentioned patent and be furnished with one or more grooves when needed to prevent local buckling. Where large covered widths and thin plate are used transverse embossments may be used for part of the lower flange in order to improve walking comfort. Since the dead load is small the case profile may span over 12 m without propping at only 1.5 mm plate thickness and about 300 mm total floor thickness. In the service state the lower flange acts as tensile reinforcement, the webs of the case profile as shear reinforcement, the reinforcement bars as shear connectors, and the concrete as compression zone. Since the lower flange is larger than the top flanges of the case profile but smaller than the concrete compression zone the floor can bear a considerably greater load than in the construction state. The load bearing capacity at supports may be increased by locally pouring concrete all the way down to the bottom of the case profile, and continuity moments at intermediate supports may be carried by additional top reinforcement in the direction of the case profile. By a small increase in the thickness of the concrete slab the floor manages to bear also running loads from traffic, which makes it suitable for parking decks and other decks. With the use of watertight concrete a waterproof deck is obtained, which already contains heat insulation and a diffusion barrier. A possible additional leakage barrier or a water-repellent preserver, open to diffusion, e.g. a silan gel treatment is easy to apply from the outside. The smooth painted underside of the case profile requires no false ceiling. Installations may easily be located in the light filling material and connections may be arranged through the concrete slab or the case profile. The sound insulating 4 properties may be further improved by perforation of the lower flange of the case profile as in an acoustic board. The fire insulation of the case profile is good due to the fact that its top is cased in the cast concrete and its bottom is painted by a fire-retarding paint. By filling the bottom of the case profile with a thin layer of a material with good thermal capacity, such as a layer of concrete grout or plaster, it is sufficient with a single treatment of fire-retarding paint. As an alternative the underside of the case profile could always be covered with some board and painted. The floor could preferably be used on sleeper walls. Since all the included material is resistant to humidity the ventilation of the foundation may be reduced. The interior filling material is also heat insulating. Water-conducted under-floor heating may easily be placed in those cuts of the case profiles where reinforcement is not located. Where the shear load capacity is sufficient the webs of the case profile may also be perforated. All these factors reduce the energy consumption of the building. When pouring the concrete light insulation products not in the shape of board, such as haydite, may have a tendency to float up. In order to prevent this behaviour the surface may be stabilised by concrete grout or covered by a net, a mat or a board. It may be foil-lined in order to reflect heat back to the building. The floor is very easy to assemble, even as simply constructed that it may be used for self-construction. All included components are so light that they may be installed by hand without big jibs. Case profiles equipped by sealing strips may be shot-fastened to the support. Installations may be put into the case profiles. Insulation boards may be pre-installed in the bottom of the case profiles, or haydite may be poured or blown into it. Reinforcement is placed into the cuts and the concrete is poured by concrete pump and finished. 5 List of illustrations Figure 1 shows in cross section through the case profiles a floor construction. Figure 2 shows in longitudinal section a floor supported by a steel frame at an exterior wall. Figure 3 shows in longitudinal section a floor supported by a timber or light gage steel structure at an exterior wall. Figure 4 shows in longitudinal section a floor supported by a sleeper wall. Figure 5 shows in longitudinal section a floor used as a roof. Figure 6 shows in longitudinal section a floor at an intermediate support. Description of applications A floor in cross section may look like figure 1. The bottom of the floor (1) consists of case profiles made of galvanised and paint coated steel sheet. The case profile may be painted by fire-retarding paint. At bottom of the case profile is a heat absorbent material (2 ), which is covered by a light sound- and heat insulating spacer material (3). In some of the cuts in the case profiles are reinforcement bars (4). The top flange of the case profile and the reinforcement are cased in a concrete casting (5). The gap between the case profiles is sealed by a sealing tape (6) or by pre-set sealing strips (8) located in groves (7) used to prevent local buckling. On top of the floor may any surface layer (9) be put, such as linoleum, an impact sound reduction mat, parquet, additional sealing, clinker e t c. 6 Figures 2, 3 and 4 show longitudinal sections of the floor supported by a steel frame (11), a timber- or light gage steel structure (12) or sleeper walls (13). In cuts without reinforcement (4) floor heating pipes (10) may be located. In figure 5 is shown a construction used as a roof with a coping (14) and with a concrete termination (15). In figure 6 is shown a construction at an intermediate support as an underlying beam (16). The concrete (17) is cast all the way down to the bottom flange of the case profile in order to stabilise the web of the case profile and to form a compression zone for the supporting moment. Reinforcement (18) is put to bear that part of the moment tension force which is not carried by the top flange of the case profile. Without restrictions, a few suggestions concerning material and dimensions should also be mentioned. The case profile (1 ) is made of black, galvanised or aluminium-galvanised coiled plate strip that may be painted, or of stainless steel in the thickness range 1 to 3 mm. The cuts in the case profiles are punched. The case profile is roll formed, which allows for excess height, or edge pressed. The case profiles are 100 to 300 mm deep and 300 to 600 mm wide. The spacer material consists of haydite or mineral wool or glass wool or a combination of these with particular densities in order to obtain the best sound performance.

Claims: 7 Claims 1. Floor structure with, in the construction state, self-supporting case profiles (1), with substantially plane single bottom flanges, from each flange edge upwards extending webs with top flanges extending inwards towards each other, the top flanges terminated by upwards extending stiffening parts with closely spaced cuts for reinforcement bars (4), characterised in that said case profiles in the service state mechanically, via the cuts, perform in composite action with a concrete slab (5) supported by a combination of different porous and light materials (3, 2), in order to produce good sound insulation, the top flanges and the reinforcement (4) being cased within the concrete slab in such a way that the bottom flange acts as a tension zone, the webs of the case profile act as shear reinforcement, the reinforcement bars act as shear connectors and the concrete slab (5) acts as compression zone. 2. Floor structure according to claim 1 , characterised in that the bottom of the case profile is in contact with a heat absorbent material layer (2) and that the underside is painted by a layer of heat retarding paint. 3. Floor structure according to any of the claims 1 to 2, characterised in that the width of the bottom flange is greater than the aggregate widths of the top flanges. 4. Floor structure according to any of the former claims, characterised in that the case profiles are roll formed from pre-painted steel sheet. 5. Floor structure according to any of the former claims, characterised in that heating pipes (10) are located in some of the cuts in the case profiles. 6. Floor structure according to any of the former claims, characterised in that the steel case profiles contain installations for electricity, water, sewage, heating or ventilation. 8 7. Floor structure according to any of the former claims, characterised in that sealing of the gap between the case profiles (1) is made by a sealing strip (8) connected to a grove (7) in the web of the case profile. 8. Floor structure according to any of the former claims, characterised in that the case profiles (1) at intermediate supports (16) are filled with concrete (17) to its full depth in order to stabilise the web of the case profile and that the floor contains top reinforcement (18) in the direction of the case profile. AMENDED CLAIMS [received by the International Bureau on 01 September 1999 (01.09.99); original claims 1 and 2 amended and renumbered as claim 1 ; remaining claims unchanged but renumbered as claims 2-7 (2 pages)] 1. Floor structure with, in the construction state, self-supporting case profiles (1 ), with substantially plane single bottom flanges, from each flange edge upwards extending webs with top flanges extending inwards towards each other, the top fianges terminated by upwards extending stiffening parts with closely spaced cuts for reinforcement bars (4), characterised in that said case profiles in the service state mechanically, via the cuts, perform in composite action with a concrete slab (5) supported by a combination of different porous and light materials (3, 2), in order to produce good sound insulation, the top flanges and the reinforcement (4) being cased within the concrete slab in such a way that the bottom flange acts as a tension zone, the webs of the case profile act as shear reinforcement, the reinforcement bars act as shear connectors and the concrete slab (5) acts as compression zone, and that the bottom of the case profile is in contact with a heat absorbent material layer (2) and that the underside is painted by a layer of heat retarding paint. 2. Floor structure according to claim 1 , characterised in that the width of the bottom flange is greater than the aggregate widths of the top flanges. 3. Floor structure according to any of the former claims, characterised in that the case profiles are roll formed from pre-painted steel sheet. 4. Floor structure according to any of the former claims, characterised in that heating pipes (10) are located in some of the cuts in the case profiles. 5. Floor structure according to any of the former claims, characterised in that the steel case profiles contain installations for electricity, water, sewage, heating or ventilation. 6. Floor structure according to any of the former claims, characterised in that sealing of the gap between the case profiles (1 ) is made by a sealing strip (8) connected to a grove (7) in the web of the case profile. 7. Floor structure according to any of the former claims, characterised in that the case profiles (1) at intermediate supports (16) are filled with concrete (17) to its full depth in order to stabilise the web of the case profile and that the floor contains top reinforcement (18) in the direction of the case profile.

Inventors: GRANSTROEM ANDERS, SVENSSON NILS-GUSTAV, GRANSTROEM, ANDERS, SVENSSON, NILS-GUSTAV
Applicants: GRANSTROEM ANDERS, SVENSSON NILS GUSTAV, GRANSTROEM, ANDERS, SVENSSON, NILS-GUSTAV
Application year: 1999
Main classification: E04B5
IPC codes: E04B5