Lightweight composite building construction

Claim 2

A lightweight composite structure, comprising at least one main composite joist consisting of two external parallel disposed sheaths, each sheath comprising a central web and two flanges constituting projecting retaining devices, and arranged face to face in such a manner that their retaining devices are directed towards one another, a plurality of first stiffening bridge means comprising means disposed internally of the sheaths interconnecting the sheaths and functioning as symmetrical struts for the sheaths and spacing them so the sheaths define between each pair of mutually opposite retaining devices a longitudinal slot of constant width, the plurality of first bridge means being spaced from one another in the longitudinal direction of the joist and frictionally engaging the sheaths for selective positioning thereof in spaced positions in said longitudinal direction, said bridge means defining two longitudinal housings between the external sheaths, one housing being positioned to the rear of each slot, in such a way that each housing is freely accessible through the slot from outside the said main joist, each first bridge means constituting means for providing a squaring-connection between two main joists.

Claim 3

A structure in accordance with claim 1, comprising in combination with at least one main joist, a secondary composite joist, parallel and complementary to the main joist, the secondary joist consisting of two parallel disposed external profiled sections, arranged face to face and each having a substantially flat central web substantially co-planar with the plane of the web of an external sheath of the main joist and two marginal retaining flanges defining a gap there between opposite said profiled sections being at least equal to the width of the slot, a plurality of second bridge means, spaced from one another in the longitudinal direction of the secondary joist and functioning as symmetrical struts for the said profiled sections, said second bridge means each comprising a central web having two flexible symmetrical longitudinal returns which grip extremities of the marginal retaining flanges of the two external profiled sections, the webs of the second bridge means extending longitudinally into one of the two housings of the main joist, the flanges of the external profiled sections being gripped between two mutually opposed retaining devices of the main joist, and each second bridge means also constituting means for forming a squaring connection between the joists.

Claim 4

A structure according to claim 2, wherein at least one of the first bridge means of the main joist consists of two lateral grippers constructed in the form of longitudinal C-shaped cross section profiled units each comprising an uninterrupted or perforated web with a flange at each end, the said grippers, on the one hand, being aranged in such a manner that the flanges on one web extend in a direction opposite to the flanges on the other web, while on the other hand the webs are joined by a quadrangular, solid or tubular enclosure, the said one first bridge means thus defining, inside of its two lateral grippers, a C-shaped cross section longitudinal housing.

Claim 5

A structure in accordance with claim 3, wherein said web comprises intrados and in which at least one of the first bridge means of a main joist comprises two symmetrical longitudinal castellated cross-section profiled units, each comprising a central web parallel to the webs of the external sheaths and two marginal flanges bearing against the intrados of the web of one of the two external sheaths, the said marginal flanges being each prolonged by a return bearing against one projecting retaining device of the external sheath, the width of the central web of each castellated profiled unit being at least equal to the gap between the two marginal flanges of said castellated profiled unit, the said two castellated profiled units also being joined to each other in such a manner that at least parts of their respective webs are situated opposite to each other and that they define longitudinal C-shaped cross-section housings.

Claim 6

A structure in accordance with claim 4, wherein the two castellated profiled units connecting the two external sheaths of a main joist are joined by a connection piece of which the central web bears against at least part of the web of each castellated profiled unit and is prolonged by at least four longitudinal returns, enabling two castellated profiled units to be joined to each other, the external surface of the web of each castellated profiled unit associated with an external sheath being situated in the plane passing through that point of the projecting retaining device of the said external sheath which is nearest to the longitudinal plane of symmetry of the main joist, in such a manner that the thickness of the said connection piece is equal to the width of the said slot.

Claim 7

A structure in accordance with claim 5, wherein the external surface of the web of each castellated profilled unit has at least one protuberance facing a corresponding protuberance on the other web, the sum of the heights of the two opposed protuberances being equal to the width of the said slot.

Claim 8

A structure in accordance with claim 6, wherein at least one of its corners comprises two orthogonal disposed main joists connected together by a ''''square'''' or angle piece, each of the two branches of the latter being locked between and in contact with the webs of the two castellated profiled units respectively of the first and of the second main joist, while that part of the second orthogonal branch of the said ''''square'''' or angle piece which passes through the said slot provided between the projecting retaining devices of the external sheaths of the second orthogonal main joist is of a thickness equal to the said slot, in such a manner as to provide between the said main joists a connection of the ''''squaring or lateral'''' type as hereinbefore defined.

Claim 9

A structure according to claim 7, wherein one of the two branches of the ''''square'''' or angle piece has perforations congruent with the protuberances on the castellated profiled units connecting the external sheaths of the main joists.

Claim 10

A structure in accordance with claim 8, wherein at least one of the transversal or longitudinal sides of the ''''square'''' or angle piece comprises means, which are constructed, for example, in the form of hooked teeth for securing the said ''''square'''' or angle piece in each of the main joists which it connects orthogonally, the said teeth interacting with and passing through perforations in the central web of the castellated profiled units and in the web of the connecting pieces, and locking means, which are constructed, for example, in the form of clips positioned opposite the internal surface of the central web of the castellated profiled units, thus locking the said teeth and preventing them from working loose and leaving the castellated profiled unit within which they are enclosed.

Claim 11

A structure in accordance with claim 9, wherein at least one of its corners comprises two orthogonal main joists connected together by the ''''perpendicular'''' system hereinbefore defined, i.e., a first main joist in which the bridge means used for the ''''squaring'''' connection is formed by two castellated profiled units fixed back to back, and a second main joist, from the end of which at least one tooth extends, prolonging the branch of an Angle piece locked between the webs of the two castellated profiled units of the said second main joist, while that castellated profiled unit of the first main joist which is remote from the second main joist extends beyond the end of the said first main joist by a length equal to the distance separating the webs of the two external sheaths of the second main joist, in such a manner that the web of the said castellated profiled unit extending beyond it is traversed by the said tooth, and means for locking the said tooth being provided opposite the internal face of the central web of the extending castellated profiled unit.

Claim 12

A structure in accordance with claim 10, wherein at least one of its corners comprises two orthogonal main joists, interconnected by the ''''squaring'''' system as hereinbefore defined, the central gap between the webs of the two castellated profiled units of the first main joist being accurately calibrated in such a manner that the second branch of the angle piece locked in the second main joist is slid into position between the said castellated profiled units of the first main joist in such a way that at the same time the intermediate flanges of the external sheaths of the second main joist are in close contact with the end cross section of the two castellated profiled units of the said first joist, in order to prevent the angle piece from bending at its most fragile part.

Claim 13

A structure in accordance with claim 11, wherein at least one joist comprises an L-shaped, T-shaped or X-shaped gripper, of which each branch consists of two arms of U-shaped cross section profile, which are face to face and symmetrical, each of the said arms having a configuration identical with that of the longitudinal cavity defined between the central part of the castellated profiled unit and the intrados of the central part of the web of the external sheath associated with the said castellated profiled unit, each arm of each branch of the said gripper being introduced into one of the said cavities, in such a way as to provide, between at least two main joists, an orthogonal connection of the ''''perpendicular'''' type or else a unidirectional prolongation.

Claim 14

A structure in accordance with claim 12, wherein the central web of at least one of the second bridge means of a secondary joist, associated with and complementary to a first main joist, is provided over at least a part of its length with locking means capable of passing through the longitudinal space provided between two mutually opposite projecting retaining devices of a further second main joist orthogonal to the main and secondary joists already mentioned, while the external sheaths of the further second main joist are situated in the plane of the sheaths and of the external profiled units respectively of the said first main joist and of the secondary joist, while at least one of the two external sheaths or at least one of the first bridge means of the second main joist also comprises devices for locking the said means.

Claim 15

A structure in accordance with claim 13, wherein at least one main joist is provided, on at least one of the ends of at least one of the two external sheaths of the said joist, with a finishing cap, for functional and aesthetic purposes, and made of metal or plastic, and covering the four non-sheathed surfaces of the extremity of the said main joist, the said cap consisting of a profiled part with a straight section identical to that of an external sheath of the said main joist and comprising, in particular, longitudinal retaining flanges and similar to the projections of the said main joist, in such a way that the removal of the said cap allows access to locking means in the said main joist, to enable accessories or a second main joist to be attached thereto.