WO1998040573A1

WO1998040573A1 - Device for detachably connecting four prefabricated building units included in a building

Info

Publication number: WO1998040573A1
Application number: PCT/SE1998/000420
Authority: WO
Inventors: Stig Olofsson
Original assignee: Concrete Volumes Sweden Ab
Priority date: 1997-03-10
Filing date: 1998-03-10
Publication date: 1998-09-17
Also published as: AU6428598A; SE9700843D0; SE508852C2; SE9700843L

Abstract

The invention relates to a device for detachably connecting four prefabricated building units included in a building (1, 2, 3, 4), a first pair of said units (3, 4) being located on top of a second pair of units (1, 2) with a horizontal border zone (11) between upper and lower units and a vertical border zone (12) between collateral units. Each one of the two upper units (3, 4) has at least one male member (8) projecting from a bottom surface, said male member being adapted to penetrate into a seat (9) in an upper side of each underlying unit (1, 2). In the horizontal border zone (11) a connecting element (10, 10') is provided that intersects the vertical border zone (12) and includes separated openings (13, 13') for receiving said male members (8). In each seat a hardened cast compound (15; 15', 15') is applied, the individual male member (8) being anchored in said cast compound (15; 15', 15').

Description

DEVICE FOR DETACHABLY CONNECTING FOUR PREFABRICATED BUILDING UNITS INCLUDED IN A BUILDING

Technical Field of the Invention This invention relates to a device for detachably connecting four pref bricated building units included in a building, a first pair of said units being located on top of a second pair of units with a horizontal border zone between upper and lower units and a vertical border zone between col- lateral units, at least one connecting element being provided in the horizontal border zone between upper and lower units, said connecting element intersecting the vertical border zone so as to interconnect the collateral building units.

Background of the Invention and Prior Art

Prefabricated building units that call for internal connection in a finished building may consist of separate room units that each is composed of a ceiling panel, a floor panel and four wall panels extending between said panels . In order to form an integrated multi-storey building such room units are mounted on one hand side by side and on the other hand on top of each other. Buildings erected in such a way are more commonly used when setting up societies associated with activities of temporary or limited duration type. An essential benefit of this type of buildings is that the separate room units may be finished and even completely equipped already in the factory, said units then being mounted in situ in a quick and effective way. Furthermore the buildings may de disassembled after completed activity at the location in question and then re-erected at another location.

A problem in connection with previously known multi-storey buildings of this type is the cross connections that are required to safely maintain the separate room units assembled in a horizontal direction. These connections are subjected to basically contradictory requirements. On one hand the connections must carry high tension and pressure loads rspectively that act in a horizontal direction between separate collateral room units and on the other hand allow a quick, flexible and simple separation of the separate room units from each other in connection with a possible disassembling of the building. In previously known buildings welded steel structures have been used for this purpose, often in the shape of sheets. However, such structures have to be cut up, e.g. by an abrasive wheel. This work is difficult and time consuming, primarily due to the poor accessibility of the connecting structures.

Objects and Features of the Invention

The present invention aims at overcoming the above men- tioned problems and simplify the connection of room or building units of the type intended to cooperate both vertically and horizontally in a building. Thus, a primary object of the invention is to provide a connecting device that on one hand guarantees a resistant cross connection between collateral building units in an erected building and on the other hand makes it possible to disassemble the units without demanding mechanical, destructive tooling. The connecting device according to the invention should thus allow disassembling of the building by simply lifting each upper building unit from an underlying unit. Another object is to provide a connecting device that is structurally simple and consequently may be manufactured and used at a low cost. In a certain aspect the invention aims to provide a connecting device especially adapted to be used in buildings erected on ground susceptible to earthquakes.

According to the invention at least the primary object is achieved by the features stated in the characterizing portion of claim 1. Preferred embodiments are further defined in the dependent claims.

Further Elucidation of Prior Art

By SE 9203001-4 it is previously known to vertically interconnect room units located on top of each other by means of male members that project from the bottom side of the indi- vidual room units, said male members being anchored in a cast compound in seats that open upwards in the upper side of each underlying room unit. In this case, however, the sole function of the male members is to make it possible to use thin ceiling or floor panels in the room units and not to interconnect room units located side by side. The horizontal connections between collateral room units of this known type of buildings are taken care of by means of welded steel structures of the type mentioned in the preamble of this description. US 4 299 065 discloses a building technique using a number of units in the form of metal sheet shells which are laterally interconnected by means of horizontal connecting elements, concrete being moulded in vertical gaps between the shells. In this case the finished building is, however, not at all intended to be disassembled.

Brief Description of the Appended Drawings

In the drawings: Figure 1 is a schematic perspective view illustrating three out of four building units that are to be connected with each other in accordance with the invention, Figure 2 is a horizontal section through portions of two building units that are horizontally interconnected by a device according to the invention, Figure 3 is a section A-A in figure 2 showing the connecting device according to figure 2 in an intersecting point between four interconnected building units, Figure 4 is a section B-B in figure 2,

Figure 5 is a horizontal section corresponding to figure 2 showing an alternative embodiment of the invention,

Figure 6 is a section C-C in figure 5 corresponding to fig^¬ ure 3, and Figure 7 is a cross-section D-D in figure 5.

Detailed Description of Preferred Embodiments of the Invention

Figure 1 illustrates three out of four room units intended to be connected with each other in accordance with the invention. The three units shown in figure 1 are designated by reference numerals 1, 2 and 3, while the fourth unit is designated 4 in figure 3. In the disclosed example each room unit includes a floor panel 5, a ceiling panel 6 and four wall panels 7, 7A These panels together form essentially par- allelepipedical, box-like units that on one hand are located side by side in single floor levels and on the other hand on top of each other in separate floor levels in the building to be erected. In connection with figure 1 it should be briefly mentioned that the individual room unit at its bottom side has a number, more precisely four, male-like projections or male members 8, that are adapted to cooperate with a corresponding number of upwardly open seats 9 at the upper side of the individual unit. In order to horizontally interconnect collateral room units connecting elements 10 are provided, the function and cooperation of said elements with the male members 8 and the seats 9 respectively being described in detail by means of two alternative embodiments illustrated in figures 2-4 and figures 5-7.

Reference is now made to figures 2-4 that show a first embodiment of the invention. In figure 3 is shown how the four room units 1-4 are assembled in a condition where the units 3, 4 are provided on top of the units 1, 2 and - like the units 1, 2 - brought together close to each other. By this arrangement a horizontal border zone 11 is formed between the units 1, 2 located at a lower floor level and the units 3, 4 located at an upper floor level. Between the collateral units 1, 2 and 3, 4 respectively there is also a vertical border zone designated 12. In the exemplified embodiment each room unit is fabricated of concrete.

In the erected building the connecting elements 10 are each provided in the horizontal border zone 11 between different floor levels, said elements 10 intersecting or bridging the vertical border zone 12. In the disclosed example the connecting element 10 consists of a single, oblong plate having through holes 13 in the area of its opposite ends, said holes 13 forming openings for receiving the male member that projects from the bottom side of each upper room unit. The individual seat 9 for each male member consists of an upwardly opening recess in the ceiling panel 6 of the individual room unit. In practice, this seat preferably has a frusto-conical shape and is fabricated by applying a filling body in the mould cavity that defines the shape of the ceiling panel.

In practice, the panel 10 may be fabricated from conventional steel and have a thickness in the range of 10-20 mm (e.g. 15 mm) and a width in the range of 150-200 mm. In a cho- sen embodiment where the panel thickness is 15 mm and the width 180 mm, the hole 13 may have a diameter of about 100 mm. The male member 8 is preferably a cylindrical steel dowel having a sheet metal collar 14 welded thereto. This collar sepa- rates an upper portion 8 ' , that together with the collar is fully moulded into the floor panel 5, from a lower portion 8" that projects from the bottom side of the floor panel 5.

In seat 9 there is a hardened cast compound 15 securing the projecting portion 8" of the dowel. In practice, this cast compound may consist of concrete, mortar or another compound that is capable of hardening after casting.

In figures 2 and 3 it is clearly shown how the individual hole 13 in the connecting plate 10 has a significantly larger diameter or cross-sectional area than the dowel 8. This means that an endless, gap-like space 16 is defined between the outside of the dowel and the edge face that defines the hole. Not only the actual seat 9, in the upper side of the ceiling panel 6, is filled with said cast compound 15, but also the endless gap space 16. The portion of the cast com- pound or body 15 that is located in the gap space thus forms a portion projecting from the upper side of the ceiling panel 6, the connecting plate 10 being secured relative to said portion at the same to as the dowel 8 is anchored by being moulded into the cast body 15. Thanks to the fact that the hole 13 has a comparatively large diameter and the plate 10 is relatively thick (e.g. 15 mm), the upper, projecting portion of the cast body 15 may be subjected to high tension or pressure loads without resulting in an excessively high hole edge pressure. In practice, the connection according to the invention is realized in the following manner. In a first step the two room units 1, 2 are mounted close to each other, and then the connecting plate 10 is applied on top of the ceiling panels of the units, the holes 13 being centred above the seats 9. Thereafter a proper amount of fresh cast compound is applied in the seats 9 and the two upper room units 3, 4 are lowered and brought to rest against the upper sides of the lower units. By doing so the lower portions of the dowels 8 penetrate into the seats and bring the cast compound to fill out not only the actual seats but also the gap space 16. In prac- tice, the gap space 16 may have a volume that corresponds to the volume of the portion of the dowel 8 that in a finally assembled state projects below the level of the upper surface of the ceiling panel. This means that the separate seat may initially be filled with cast compound up to the level of said upper surface and then the compound displaced by the dowel in a precise way fills out the gap space in question. When the compound, after a certain curing time, has hardened the same forms a rigid body relative to which both the dowel 8 and the plate 10 are secured in a state where horizontal movements, between the room units in the different floor levels, are prevented to an essential degree. If a need should arise to disassemble the erected building the described connection does not prevent vertical movements between the upper and the lower room units. Thus, each upper room unit may, without significant resistance, be removed from the associated lower unit by simply being lifted from said lastmentioned unit. Certainly, the dowel is adhered in the associated cast body, but the lifting forces required to overcome said resistance are negli- gibly small in comparison with the horizontal pressure or tension forces that the connection according to the invention can withstand.

Reference is now made to figures 5-7 which illustrates an embodiment of the connecting device according to the inven- tion that is especially suitable for buildings in earthquake areas. In this case the connecting element 10' is composed of two oblong part plates 17, 18 that each in the area of their opposite ends has cups 19, 20 that preferably have rotary symmetrical shape. More specifically, the two cups are made with a frusto-conical shape. The separate cup 19 included in the upper part plate 17 has a smaller diameter or width than the corresponding cup 20 of the lower part plate. By this arrangement an annular space 21 is defined between the outside of cup 19 and the inside of cup 20. In practice, the two part plates 17, 18 may each be thinner than the plate 10 described in connection with the embodiment according to figures 2-4. For instance, the plates may consist of sheet metal having a thickness in the range of 3-7 mm, preferably about 5 mm. The cups 19, 20 may be designed by pressing and then welded in connection to holes in the part plates. The upper open portion of the inner cup 19 forms an opening 13' for the male member. The male member 8 may also in this embodiment consist of a cylindrical dowel of the type previously described. In the annular space 21 a viscous or plastic compound of suitable type is introduced. This compound is not adapted to harden, but should continue to maintain its plasticity in order to allow the cups 19, 20 to move horizontally relative to each other without being obstructed, to a larger degree, by the" filling compound. The external, lower cup 20 is on the other hand anchored in a compound 15' , suitable for casting, e.g. concrete or mortar, that has hardened after curing. In an analogous way the dowel 8 is anchored in a cast compound 15", hardened by curing, that has been applied in the upper cup 19. In practice, a friction reducing means may preferably be used in the border surface between the part plates 17, 18 to facilitate relative gliding movements between said plates. For instance, the surfaces of the plates facing each other may be coated with polytetrafluoro ethylene or the like. In a normal condition the described connecting device may carry high tensile and pressure loads in the horizontal direction without movements of the room units relative to each other. If the building would temporarily be subjected to extreme shakings or shocks, e.g. as a result of earthquake phenomena, the cooperation between the lower and upper cups on one hand and the plastic compound on the other hand allow a certain, flexible movement between the units. In such a way it is guaranteed that the building may be subjected to extraordinary side or cross forces without generating breaking damages in the area of the connecting devices.

In practice, the connecting devices according to the invention are used in all border zones between the lower and upper floor levels of the building. On the contrary the lower parts of the room units in the lowest floor level may be secured to the foundation structure in a different way. Also the roof structure above the upper floor level may be connected to the lower room units in another arbitrary way.

Although the invention has been exemplified above only in connection with room units of the type shown in figure 1 it may also be applied for internally connecting other arbitrary building units or elements, e.g. panels for the facade.

Claims

1. Device for detachably connecting four prefabricated building units (1, 2, 3, 4) included in a building, a first pair of said units (3, 4) being located on top of a second pair of units (1, 2) with a horizontal border zone (11) between upper and lower units and a vertical border zone (12) between collateral units, at least one connecting element (10, 10') being provided in the horizontal border zone (11) between upper and lower units, said connecting element (10, 10') intersecting the vertical border zone (12) so as to interconnect the collateral building units (1, 2 and 3, 4), c h a r a c t e r i z e d in that each one of the two upper units (3, 4) has at least one male member (8) which projects from a bottom surface thereof and is adapted to penetrate into a wider, upwardly opening seat (9) in an upper side of each underlying unit (1, 2), and to extend through one of two spaced-apart openings (13, 13') in the connecting element (10, 10'), and that each seat contains a hardened cast compound (15; 15', 15") in which the individual male member is anchored, the individual opening (13, 13') in the connecting element (10, 10') having a larger cross-sectional area than the male member (8) in order to form, between the outside of the male member and the portions of the element confining the opening, an endless, gap-like space (16, 16') which is filled out by said cast compound.

2. Device according to claim 1, c h a r a c t e r i z e d in that the connecting element (10') is composed of two oblong part plates (17, 18) having cups (19, 20) in the area of their opposite ends, the cups being associated with an upper part plate (17) having less width than the cups (20) being included in the lower part plate (18), whereby an annular space is confined between pairs of cooperating cups, said space containing a viscous filling compound (21) , and that hardened cast compounds (15', 15") are applied on one hand in a space between the outside of each separate cup (20) and the inside of the associated seat (9) and on the other hand in a space between the inside of the upper cup (19) and the outside of the male member (8) .

3. Device according to claim 2, c h a r a c t e r i z e d in that said cups (19, 20) are of frusto-conical shape.

4. Device according to anyone of the preceding claims, c h a r a c t e r i z e d in that the male member consists of a cylindrical dowel (8) having a collar (14) secured thereto, said collar (14) separating a lower projecting portion (8") from an upper portion (8') that is anchored in the lower por- tion of an associated building unit.