BEAM OR GIRDER FOR BUILDING CONSTRUCTION AND A BUILDING UNIT INCLUDING SAID BEAM OR GIRDER, AND A METHOD OF MANUFACTURING THE BEAM OR GIRDER

Abstract: A beam or girder (1) for building construction comprises a base profile (3-5), mainly for tensile loads and an upper covering plate (2) of a mainly for compressive loads suitable material, which is considerably stiffer in all directions than the plate of the base profile (3-5), said covering plate (2) being rigidly and moment transmittingly (resistant to bending moments) connected directly to the base profile via a glue layer, so that the covering plate (2) and the base profile (3-5) form a static cooperating supporting unit. Since the covering plate (2) has the same width as the base profile (3-5) and along both its longitudinal sides flush with the sides of the base profile, and that the rigid connection between the covering plate and the base profile also comprises securing elements extending fully or partly through the covering plate (2), there is hereby achieved a form stable, comprehensively applicable beam or girder of low weight and a high strength, and a predetermined curvature in the longitudinal direction of the beam is easy to adapt to the application conditions during its manufacture.

Description: BEAM OR GIRDER FOR BUILDING CONSTRUCTION AND A BUILDING UNIT INCLUDING SAID BEAM OR GIRDER, AND A METHOD OF MANUFACTURING THE BEAM OR GIRDER. The present invention relates to a beam or girder for building construction and of the kind mentioned in the introductory part of claim 1. Such beams of steel, aluminium or plastic are known from the building industry, and a drawback by said known beams are, e.g. by use as horizontal supporting longitudinal girders, that a considerable part of their wall thickness is involved in carrying the weight of the girders themselves in order to keep the deflexion of the girders below a given value at a given span. From the specification and drawing of DE published patent application No. 2,520,255 is known a light building element constructed by structural elements or structural members in which roofing plates and channel configurated base members form an integrated unit, such as for roofing elements each consisting of at least one open base profile glued directly onto an upper covering plate forming the covering as well as the loading absorber, and whereby the covering plate is wider than the base profile and along both the longitudi¬ nal sides thereof extends outside the base profile. This implies that each covering plate has a freely protruding, unsupported side part getting a certain deflexion by loading of the covering plate. Said deflexion exposes the joint between neighbouring covering plates to great material loads and renders it practically impossible in and below the joint to obtain reasonable diffusion resistance with known means. This is a drawback being very serious by roofing structures. It is the purpose of the present invention to provide a beam or girder which, if used for reinforcing structural plates, may eliminate said drawbacks, and which is also suitable as an independent unit for use as horizontal longitudinal girder, separately or built in in ceiling or roofing constructions, and for use as column per se or for building in in vertical wall constructions, particularly where a good heat isolation and diffusion resistance is desired. This is achieved by a beam or girder according to the invention, said beam being characteristic by the items set forth in the characterizing clause of claim 1. Thereby is separately achieved a light beam construction with a high supporting ability by use as horizontal or inclined girder in relation to the weight of the beam itself. Seeing that each beam per se is a finished unit, they might by simple means and before their mounting on a roofing or floor construction plate for forming a building element be provided with a predetermined curvature in their longitudinal directon, so that the roof or the floor in mounted and loaded condition e.g. becomes totally planar. Furthermore, seeing that the beam of this invention has no protruding side edges for the covering plate, the beam may be arranged at the outer plate side edges of the building element to be reinforced by means of beams of this invention, whereby the deflexion of said side edges become as small as possible during loading, and consequently a lasting diffusion resistance in the joining between two neighbouring building elements is achieved and secured by common tightening means. The rigid edge joining thereby achieved between neighbouring building elements becomes able to transfer high bending moments, and the supporting ability of the building elements locally in the joinings or at the longitudinal edges becomes high. When the beam is used in heat and sound isolating floor, ceiling and roofing elements where isolating material, such as mineral wool, is arranged inside the beams and between the beams, a high heat isolating ability and a good sound isolation is achieved at the joints of the elements, partly because the base profile material of the beam is relatively thin and therefore is conducting heat and sound relatively poorly, and partly because the beams in the joints can be arranged directly abutting the beams of neighbouring elements. By a material which is mainly suitable for compres- sive loadings is to be understood a material being better suited for compressive loads than for tensile loads. As examples thereof may be mentioned massive veneered or laminated wood, cement bound or adhesive bound chip board, cell plast or wood core plywood. By a material mainly suitable for tensile loadings is to be understood a material being better suited for absorbing tensile loads than compres¬ sive loads. As examples may be mentioned relatively thin sheet or plate material of metal, such as iron, steel, brass and aluminium, and steel and/or fiber reinforced concrete, plastic or wood. None of said materials has, however, a Young's modulus below 5800 MPa, a bending strength below 49 MPa, a tensile strength below 49 MPa and a compressive strength below 19.6 MPa in the temperature area -40 to +50 degrees C. An embodiment of a beam according to claim 2 may preferably have a further, mainly for compressive loads suitable plate being firmly secured over the total length of the beam to that part of the beam located most distant from the covering plate closing the beam. Thereby is provided a more universally applicable beam, seeing that it is suitable for applications as a heavy loaded longitudinal girder, e.g. as cantilever beam, and as a column or a vertical longitudi¬ nal girder. The present invention also relates to a building unit according to claim 4, wherein the beam according to the invention is used, and where two or more beams are arranged as longitudinal girders in the building unit, which might be a roofing element, a ceiling element, a wall element or a floor element, said building unit having two of the beams arranged at each longitudinal side edges of the building unit, where they form the longitudinal sides of the building unit. Thereby is achieved that the building units may absorp forces or loads in the plane of the building element and loads from the facades, more secure or safe element joints, seeing that the beams of the elements at the side edges may be secured directly to each other. Furthermore may the elements at the joinings easily by known means be made diffusion resistant and/or may absorp extra loading from e.g. tubing, lighting equipment etc. below the element joinings and possible extra loadings from roofing units or installa- tions arranged on a roof above the element joinings or from heavy objects, such as shelves arranged on a floor above the element joinings. Said arrangement of the beams in the elements furthermore implies that arbitrary distances or openings for staircases, lifts, skylights etc. are possible between the beams forming the strong supporting side edges of neighbouring elements. Furthermore, relatively larger recesses in the elements themselves and between the beams can be performed at given element dimensions 1) for skylights, chimneys, roof caps etc. in roof elements, 2) for chimneys, staircases, lifts and dropping pits in ceiling or floor elements, and 3) for doors, hatches and windows in wall elements, where such relatively high loadings for the building units are absorbed directly by the beams. This would not have been possible if the covering plates of the beams were wider than the base profile of the beam, or if the building units did not have a beam far out at its longitudi¬ nal edge. Furthermore is achieved that the elements with their beams arranged at their side edges can be assembled resistant to bending moments directly at their side edges, that the elements being completely alike at both side edges, so that they can be rotated 180 degrees about an axis perpendicular to the element during the mounting, which again means that fewer element types may be necessary for a given building, particularly if the building elements of the invention have box shaped beams at their longitudinal sides, and that a greater freedom of choice is obtained during the mounting. Furthermore is achieved that the vapour seal of the element can be hidden in the longitudinal sides of the element, so that said vapour seal cannot be damaged during transportation and mounting of the building element. Furthermore, the invention relates to a method according to the introductory clause of claim 6 for manufac- turing a longitudinal closed beam or girder according to the invention for building purposes, and the method is charac¬ terized by the items set forth in the characterizing clause of said claim. Thereby it becomes possible not only to manufacture rectilinear beams, but also upwardly and down¬ wardly curved beams, seeing that the curvature is decided by the longitudinal curvature of the base profile, before its covering plate is secured thereto. The invention will now be described in more detail in connection with some embodiments and with reference to the drawing in which fig. 1 shows two known beams having uniform wall thickness, fig. 2 a beam according to the invention, fig. 3 in perspective and partly in section an end embodiment of a building unit according to the invention, fig. 4 a cross section through an embodiment of a building unit according to the invention, corresponding to the one shown in fig. 3, fig. 5 another embodiment of a building unit according to the invention and intended for a vapour barrierless roof, fig. 6 a cross section through a longidutinal joint between two building units according to the invention, fig. 7 a section through an end joint between two building elements according to the invention above a supporting girder, figs. 8-10 cross sections through embodiments for beams according to the invention, figs. 11-14 cross sections through beams according to the invention with an extra compressive load resistant plate at the inside of the beams, figs. 15-18 embodiments for the beam according to the invention with an extra compressive load resistant plate at the outside of the beams, fig. 19 a cross section through a further embodiment for the beam according to the invention, and fig. 20 a cross section through a beam with two mutually secured base profiles for fire protectional purposes. Fig. 1 shows two known beams, socalled box girders, with square cross section and rectangular cross section, respectively, and of a uniform wall thickness. Fig. 2 shows a beam 1 accordig to the invention, where one of the plane sides 2, 3, 4, 5 of the beam consists of a covering plate 2 of a mainly for compressive load suitable and resistant material of a thickness of 1,5-115, preferably 32 times greater than the thickness of the abutting sides 3, 5 of the beam 1. The covering plate 2 e.g. may be made of 22 mm thick waterproof plywood, and the base profile plate 3, 4, 5 may be a 0.7 mm thick galvanized steel profile, the height of which varies according to its span or other conditions, under which the beam is to be used. The remaining sides 3, 4, 5 of the beam 1 being performed in one unit as a base profile consist of a mainly for tensile load suitable and resistant material as further defined in the introductory clause of the specification, and the mainly for compressive load suitable covering plate 2 is secured directly edge flushing and resistant to bending moments to the two longitudinal adhesive surfaces 6, 7 of the profile unit 3, 4, 5, said surfaces as shown may be performed as edge flaps or flanges 6, 7. The securing means are chosen in dependence on which materials are to be assembled, and said securing means include a adhesive assembly and, for further reinforcement thereof, a screw assembly, bolt assembly, nail assembly or the like. Thereby is provided a beam having a low weight and a large supporting ability and without having any protruding side edges, and which beam can be manufactured at low costs. The supporting ability may be further increased by arranging bulkheads 10 inside the beam 1 with predetermined spaces as indicated in fig. 3. Each bulkhead 10 is e.g. secured perpendicularly to at least three of the inner walls of the beam, e.g. on the inner sides of the sides 3, 4 and 5. Fig. 3 shows a building unit or module 12 in which the beam 1 according to the invention is used, and beams 1 are arranged as longitudinal girders in the building unit 12, which may be a roof element as shown, a ceiling element, a wall element or a floor element. Fig. 3 shows furthermore that one of the beams 1 is arranged at each longitudinal side edges of the building element 12. The roof building unit shown in fig. 3 may e.g. at its upper side have a 16 mm thick waterproof plywood board 14 which is or will be covered by roofing foil or roofing felt. Said plywood plate 14 is directly secured to the three shown longitudinal closed beams 1 by glueing and nails or screws, and directly below the beams 1 may be arranged a vapour seal 15, e.g. of PVC foil or of the material being known as hygrodiode, dampcourse or vapour seal. Below the vapour seal may be arranged a heat isolating ceiling covering 16 of e.g. mineral wool or wood¬ wool building slabs, and said ceiling covering 16 is secured and protected at the longitudinal side edges of the element 12 by corner steel 17 secured to the beams 1. Between the beams 1 may be arranged a mineral wool isolation 18, and a mineral wool isolation not shown may be arranged inside the beams themselves. Fig. 4 shows a section perpendicularly to the longitudinal direction of the building unit in fig. 3. As will be seen, there is enough room between the beams 1 for large throughgoing openings in the building unit without the supporting ability of the element thereby being considerably reduced. Fig. 5 shows a roofing element with the beams 1 in another arrangement. Here an isolating ceiling covering 16 is placed between the beams 1, and the vapour seal 15 is arranged above the beams 1 and the ceiling covering 16, but below the plywood board 14. The ceiling covering 16 which along with the vapour seal 15 is secured e.g. by glueing to the plate 14, is made e.g. of isolating plates with a high cohesive force and being known as isolation plates from Dow Danmark A/S in the STYROFOAM®-programme of said company. Upon the plywood board 14 is arranged a socalled outer isolation 20 which is vapour proof, heat proof and weather proof. Fig. 6 shows a longitudinal assembly between the longitudinal sides of two building units 12. Here is used a locking slab 22 above the joint between the elements and a diffusion resistant and heat isolating sealing band 23 between the two abutting beams 1 of the two neighbouring elements. Since the width of the construction plate 14 is less than the width of the building unit 12 with a value corresponding to the width of the locking slab 22 for the mutual locking of the neighbouring building elements, a further advantage of the beam according to the invention is achieved, due to its location along the longitudinal sides of the building unit, seeing that the element width e.g. can be made 2,5% wider than the present standard width of 244 cm by the same material consumption and fewer working operations. This is due to the fact that construction plates of standard width may be used, which width in Denmark are 244 cm as delivery measure, whereby the building units can obtain the convenient width of 250 cm and the locking slabs get a width of 6 cm. Fig. 7 shows an end assembly or joint between the ends of two elements 12 above a supporting girder 25, which support the units 12 on the beams 1 of the elements at their ends immediately below the reinforcing end bulkheads 10. Also by this assembly is used a locking slab 27. Figs. 8-19 show some embodiments of the beam accor- ding to the invention which all have been provided with a covering plate 2 and with abutting base profile sides 3 and 5 of less thickness. Some of the beams, viz. the ones shown on Figs. 11-18, have a further, mainly for compressive load suitable and resistant reinforcing plate 8 firmly secured over the full length of the beam to that part of the beam being most distant from the covering plate 2. Said extra reinforcing plate 8 may as shown in figs. 11-14 be arranged inside upon the beam 1 or as shown in Fig. 15-18 be arranged outside upon the beam 1. Such beams as shown in Figs. 11-18 are particularly suitable for use as girders in form of cantilevers or as wall supporting beams and columns. In an .embodiment of the invention not shown, the base profile side 4 may be a planar steel plate, which plate resistant to bending moments is secured to the sides 3 and 5 which may be U-formed so that short U-profile sides form the edge flanges 6, 7 of the base profile and the edge flanges for securing to the sides 3 and 5 of the steel plate 4 by riveting, welding or the like. As examples of the relation between the wall thicknesses in the plate 2 and the plate of the base profile 3-5 can be mentioned following values in millimeters: 45:30, 40:21, 15:5, 20:5, 25:5, 35:5, 22:2, 24:2, 15:1, 20:1, 25:1, 20:0,7, 22:0,7, 32:1, 40:1, 100:2, 35:0,7, 60:1, 42:0,7, 50:0,7, 80:1, 90:1, 100:1, 70:0,7, 105:1, 80:0,7, 115:1. The proportionals selected depends on the expected loadings for the beam, on the materials used and securing methods used and of the available standardized material thicknesses. Fig. 19 shows an embodiment of the beam 1, when it is expected to be exposed to particularly high tensile loadings in the base profile sides 3 and 5, or where the sides 3 and 5 are manufactured in thicker material, such as fiber reinforced plastic. Fig. 20 shows an embodiment of a beam according to the invention, whereby a better fire resistance as well as a greater strength is achieved, so that the duration of the higher fire resistance is increased. In the outermost base profile 3, 4, 5 and at a distance therefrom there is inserted an inner base profile 30. In the space 31 between the two base profiles is arranged a heat isolating material 32, 33, of which at least the upper material 33 is nail proof and glued to the upper end parts of both profiles. The upper surface 34 of the upper material 33 is flush with the upper end edges of the two profiles 3-5, 30 and form a securing, abutting and glueing surface for the covering plate 2. A construction plate 14 is secured to the middle of the covering plate 2, said construction plate 14 here is made of a steel plate with intermediate reinforcing ribs.

Claims: P a t e n t C l a i m s : 1. Beam or girder for building construction and of a polygo¬ nal, geometric shape, such as box shape, trapezoidal shape or triangular shape, wherein the beam (1) comprises a base profile (3-5) of a mainly for tensile loads suitable material and an upper covering plate (2), the base profile of a mianly for compression loads suitable material consisting of a upwardly open U or V shaped metal profile (3-5 or 3 and 5) of a sheet or thin plate material with adhesive surfaces (6, 7) being upwardly and inwardly directed on the upper side of the profile, and the upper covering plate (2) e.g. consisting of plywood which is considerably stiffer in all directions than the plate of the base profile (3-5), said covering plate (2) being firmly connected directly and resistant to bending moments onto the base profile via a glue layer on the total surface of the adhesive surfaces of the base profile, so that the covering plate (2) and the base profile (3-5) form a static cooperating supporting unit, c h a r a c t e r i z e d in that the covering plate (2) has the same width as the base profile (3-5) and along both longitudinal sides flushes with the sides of the base profile, and that the rigid connection between the covering plate and the base profile also comprises securing elements, such as screws, nails, rivets or the like elements extending fully or partly through the covering plate (2). 2. Beam according to claim 1, c h a r a c t e r i z e d in that a further, mainly for compressive load resistance suitable plate (8) is rigidly secured over the total length of the beam (1) to that part of the base profile being most distant from the covering plate (2). 3. Beam according to claim 1, c h a r a c t e r i z e d in that a further U or V shaped base profile (30) is arranged inside and at a distance to the first U or V profile (3-5 or 3 and 5), that the space (31) between the profiles in the bottom and a part of the sides is filled with a heat isola¬ ting material (32), while the space (31) between the upper side parts of the profiles is filled with a nail proof heat isolating material (33), which is glued to both side parts of the profiles, and the upper surface (34) of which is secured to the covering plate (2). 4. Building unit, wherein the beam according to claim 1, 2 or 3 has been used, and wherein two or more beams are arranged as longitudinal girders in the building unit, such as a roofing member, a ceiling member, a wall member or a floor member, c h a r a c t e r i z e d in that two of the beams (1) is arranged along and at the longitudinal side edges of the building unit (12), where they form the longitudinal sides of the building unit. 5. Building unit according to claim 4, where two or more beams are secured to a building board or construction plate (14) for the reinforcing thereof, c h a r a c t e r i z ed in that the width of the construction plate (14) is less than the width of the building unit (12) with a value correspon- ding to the width of a locking slab (22) for mutual locking of neighbouring building units. 6. Method for the manufacture of a beam (1) for building construction according to claims 1, 2 or 3, wherein a two- or three sided base profile (3-5, 30) being open to one side is formed by a thin, mainly for tensile loads suitable plate, and wherein bulkhead plates (10) are arranged, preferably into beams (1) having long spans, said bulkhead plates having predetermined spaces in the longitudinal direction of the beam (1) and being perpendicular to the inner sides of the base profile (3-5, 30) not yet closed, c h a r a c t e r i z e d in that the longitudinal open side of the base profile (3-5, 30) is then closed by securing a covering plate (2) to its two adhesive surfaces (6, 7, 30) in a way resistant to bending moments, said covering plate (2) being of a mainly for compressive loads suitable material and having a width of same measure as the width of the open base profile. 7. Method according to claim 6, wherein the base profile is trilateral, c h a r a c t e r i z e d in that a longitudinal V-profile (35) is arranged in the inner of the base profile (3-5, 30), the flap edges of the V-profile (35) being supported in the lower two corners of the U-profile, and the bottom of the V-profile meet the middle of the covering plate (2) when it is secured to the base profile (3-5, 30).

Inventors: SVENSSON PEEHR MATHIAS OERNFEL, SVENSSON, PEEHR, MATHIAS, OERNFELDT
Applicants: SVENSSON PEEHR MATHIAS OERNFEL, SVENSSON, PEEHR, MATHIAS, OERNFELDT
Application year: 1992
Main classification: E04C3
IPC codes: E04B5, E04C3