EP1099805B1

EP1099805B1 - Structural support

Info

Publication number: EP1099805B1
Application number: EP20000309896
Authority: EP
Inventors: Roy John Burns
Original assignee: Voestalpine Metsec PLC
Current assignee: Voestalpine Metsec PLC
Priority date: 1999-11-09
Filing date: 2000-11-07
Publication date: 2004-06-09
Anticipated expiration: 2020-11-07
Also published as: GB9926415D0; EP1099805A1

Description

This invention relates to a structural support assembly particularly for supporting an existing roof structure.
It has been recognised that certain roof structures assembled from reinforced concrete panels have, over a number of years, suffered a gradual deformation in which the panels have sagged between their points of support. It is an object of the present invention to facilitate the provision of a structural support assembly in conjunction with such a roof to provide additional support for the panels, the structural support assembly being carried by the original existing roof support structure.
A particularly well known form of roof structure includes elongate, parallel, I-beams spanning load bearing walls of the building and providing the primary support structure for the roof panels. Very frequently the I-beams are formed, in order to save weight and metal, with apertures equidistantly spaced along the web of the I-beam. Such an arrangement is disclosed in DE-A-2 314-373. It is a particular object of the present invention to provide a structural support assembly which can be anchored to the existing I-beams without requiring in situ drilling or other machining of the I-beams, while providing a flexible means of support for additional, subsidiary, beams.
In accordance with the present invention there is provided a structural support assembly comprising a first clamp having a first jaw member arranged to engage one face of the web of an I-beam, a second jaw member arranged to engage the opposite face of the I-beam and securing means joining the first and second jaw members and extending, in use, through an existing aperture of the I-beam, the jaw members being shaped to span said aperture of the web of the I-beam; a second, similar clamp the securing means of which extends through the same, or an adjacent aperture of the I-beam; and an elongate angle member extending parallel to the I-beam and secured to said first jaws of said first and second clamps such that one limb of the angle member is, in use, substantially horizontal so as to be able to form a support ledge for one end of a subsidiary, roof supporting beam of the assembly in use.
Preferably said angle member is secured to said first and second clamps by the securing means securing the first and second jaws of each clamp together.
In accordance with the further aspect of the present invention there is provided a method of supporting a structural support assembly from an apertured I-beam comprising positioning a first jaw member of a first clamp against one face of the web of the I-beam, positioning a second jaw member of the first clamp against the opposite face of the I-beam, using securing means joining the first and second jaw members to clamp the jaw members against opposite faces of the I-beam, the jaw members being shaped to span an aperture in the web of the I-beam, securing a second similar clamp in the same way through the same, or an adjacent aperture of the I-beam, and, securing an elongate angle member to said first and second clamps with the angle member extending parallel to the I-beam, whereby the angle member can form a support ledge for one end of a subsidiary, roof supporting beam of the structural support assembly.
Preferably the method includes securing said angle member to said first and second clamps by means of the securing means securing the first jaw member of each clamp to the second jaw member of that clamp.
Preferably the same operation of said securing means clamps said jaw members to said web and said angle member to said clamps.
Desirably said jaw members of said clamps are positioned at right angles to the length of the I-beam.
Preferably said jaw members abut the upwardly presented face of the lower flange of the I-beam.
One example of the invention is illustrated in the accompanying drawings wherein:-
Figure 1 is a diagrammatic plan view of part of a structural support for a concrete panel roof,
Figure 2 is a diagrammatic perspective view of part of a lattice beam for use in the structural support of Figure 1,
Figure 3 is a diagrammatic side elevational view of a subsidiary beam support structure clamped to an existing I-beam,
Figure 4 is a diagrammatic sectional view, to an enlarged scale, on the line 4-4 of Figure 3,
Figure 5 is a view in the direction of arrow A in Figure 3 illustrating a pair of subsidiary beams supported from a main I-beam,
Figures 6,7 and 8 are diagrammatic views respectively of additional features of the support structure of Figure 1, and
Figure 9 is a view similar to Figure 5 of a modification.
Referring to the drawings, beams 11 are existing conventional hot rolled steel I-beams the web 12 of which is formed with apertures 13, generally of diamond shape, and equidistantly spaced along its length. Such beams are well known. In Figure 1 the beams 11 are shown parallel to one another and span load bearing walls of the building, the load bearing walls being parallel to one another and at right angles to the length of the beams. It is to be understood that this is a simplistic view of a building roof construction, and there may be other I-beams 11 running at right angles to the I-beams shown in Figure 1 and supported by columns or other vertical structural elements in the building. The main beams 11 constitute the primary support structure for the roof construction. A known problem exists where the roof construction consists of a plurality of precast, reinforced concrete panels spanning adjacent main I-beams 11. It is recognised that over a period of years the central regions of certain forms of concrete panels may sag downwardly between the main beams 11 prejudicing the structural integrity of the roof. It has been proposed to build a cradle of lattice beams 14 carried from the main beams 11 and the vertical structural supports of the building so that the cradle of lattice beams can provide a supporting structure intermediate the beams 11 to accept the load of the deforming concrete panels.
In Figure 1 individual lattice beams spanning main beams 11 are denoted by the reference numeral 14, while lattice beams spanning the lattice beams 14 are denoted by the reference numeral 15. Each of the lattice beams 14, 15 is in the form of upper and lower elongate outwardly flanged channels 16, 17 spaced apart by a zig-zag arrangement of stretchers 18 welded to the base walls of the upper and lower channels 16, 17. As can be seen in Figure 2 the upper channel member 16 is longer than the lower channel member 17 so as to protrude at both ends of the lattice beam beyond the channel member 17. Additional pairs of stretchers 19 join the ends of the lower channel member 17 to the upper channel member 16, the stretchers 19 being welded to the flanges of the channel members 16, 17 rather than to the base walls as is the case with the stretchers 18.
Clearly it is extremely desirable to be able to construct the cradle of lattice beams 14, 15 with minimum disruption to the existing structure of the building. Naturally drilling or other cutting or shaping of the main beams 11 is extremely undesirable in view of their location in the roof space of the building, and Figures 3, 4 and 5 illustrate a convenient way of supporting the lattice beams 14 from the main beams 11.
Figure 3 clearly shows the spaced, generally diamond-shaped apertures 13 in the vertical web 12 of the I-beams 11. First and second clamps 21, 21a are secured to the web 12 at adjacent apertures 13. Each clamp 21, 21a includes front and rear jaws engaging opposite faces of the web 12 respectively, and spanning the respective aperture 13. The front and rear jaws 22, 23 of the clamp 21 are identical, and each consists of a length of rectangular-section channel. Each of the jaws 22, 23 is cold rolled in galvanised mild steel, and the jaws are each arranged with their open face presented to the web 12. The length of each jaw 22, 23 is such that the jaw can fit vertically between the upper and lower flanges of the beam 11, being long enough to span the vertical dimension of the respective aperture 13. Although not shown in Figure 3, it is desirable that the jaws 22, 23 have their low ends seated on the upper face of the lower flange of the beam 11. The base webs of the channels defining the jaws 22, 23 are apertured to receive elongate fixing bolts 24 which extend through the jaws 22, 23 and the respective aperture 13, and which are tightened to clamp the jaws 22, 23 against opposite faces of the web 12.
It will be recognised that the channel sections defining the jaws of the clamps 21, 21a are parallel, and are vertically orientated in use. In order to provide a support for an end of one or more lattice beams 14 there is provided an elongate mild steel angle 25 which is disposed horizontally, and spans the base webs of the front jaws 22 of the clamps 21, 21a. The angle member 25 is also cold rolled from galvanised mild steel, and comprises a pair of limbs disposed at right angles to one another. The vertically oriented limb of the angle member 25 is secured to the jaws 22 of the clamps 21, 21a by the upper fixing bolts 24 of the clamps which are extended to pass through the limb of the angle member 25 and thus clamp the angle member 25 to the jaws 22 at the same time as clamping the jaws 22, 23 to the web 12. It will be recognised that the other limb of the angle member 25 is thus generally horizontally disposed parallel to, but below, the plane of the upper flange of the beam 11. The horizontal flange 25a of the angle member 25 thus constitutes a horizontal ledge upon which one end of the upper channel 16 of a lattice beam 14 can be seated.
Any convenient arrangement can be provided for clamping the end of the upper channel 16 of the lattice beam 14 to the angle member 25, and conveniently a hooked screw clamping device 26 of the kind known as a "LINDAPTER" is utilised.
Figure 5 illustrates that angle members 25 can be secured by the bolts 24 to both front and rear jaws 22, 23 of the clamps 21, 21a so that beams 14 can be supported at right angles to, and on opposite sides of the beam 11. Shims or other packing members can be interposed between the members 25 and the beams 14 if necessary to adjust the height and/or inclination of the beams 14.
Figure 6 illustrates one end of the beam 14 supported on an angle member 25 as described above, with the opposite end of the beam 14 supported at a load bearing wall of the building. Figure 7 shows the load bearing wall end of the beam 14 in more detail. It can be seen in Figure 7 that the load bearing wall 30 (in this case a cast concrete wall) is formed with a horizontally extending pocket 31 the lower wall 32 of which defines a horizontal ledge. A plurality of vertically orientated bolts 33 were cast into the wall 30 when the wall was constructed, the threaded ends of the bolts projecting upwardly through the ledge 32 into the pocket 31. The pre-existing bolts 33 are arranged in adjacent pairs, and each pair of bolts is used to secure a right angle cleat 34 to the ledge 32, shims or other packing pieces 35 being interposed between the horizontal flange of the cleat 34 and the ledge 32 if necessary to adjust the height of the cleat.
The vertical flange of each cleat 34 extends downwardly parallel with the face of the wall 30 and has a channel, or angle member 36 bolted thereto. The channel or angle member will span two or more cleats 34 in a manner similar to the angle member 25 associated with the beam 11. The angle member or channel 36 has a horizontal upper face providing a seating surface for the upper channel member 16 of the lattice beam 14. Again shims or packing pieces 35 can be interposed between the upper face of the channel or angle member 35 and the channel member 16 of the beam 14. The end of the channel member 16 can be secured to the angle member 35 in any convenient manner, for example using a " LINDAPTER" as described in relation to the opposite end of the beam 14.
Figures 6 and 8 illustrate how lattice beams 15, substantially identical in design to the lattice beams 14 can be supported from the lattice beams 14 so as to span adjacent lattice beams 14.
Each opposite end face of each upper channel member of a beam 15 has a right angle cleat 37 welded thereto. The cleat is simply a short length of right-angled cold rolled mild steel which has its vertically extending flange welded to the vertical end face of the channel member 16 of the beam 15. The cleat 37 is so positioned that the upper face of the horizontally extending flange of the cleat is generally flush with the top surfaces of the outwardly extending flanges of the channel member 16, and the beams 15 are formed so that their length, excluding the protruding portions of the cleats 37 at opposite ends, is equal to the spacing between parallel beams 14. Thus a beam 15 can simply be placed between parallel beams 14 so that the horizontal flanges of the cleats 37 engage the upper faces of the channel members 16 of the beams 14 whereby the beams 15 are carried by the beams 14.
In use, a cradle of beams 14, 15 is constructed beneath the concrete roof panels, supported by the existing roof support structure. Elongate inflatable elements are then interposed between the upper faces of the horizontal flanges of the beams 14, 15 and the underside of the concrete panels, and the elements are then inflated to fill the gap between the cradle of beams 14, 15 and the panels such that the cradle, and ultimately the original support structure including the supporting walls 30 and the beams 11, accepts the load of the concrete panels. Thereafter grout is introduced into the gap between the upper surfaces of the flanges of the beams 14, 15 and the underside of the panels so that after the grout solidifies it transfers the load of the panels to the supporting cradle.
Figure 9 illustrates a modification of the arrangement illustrated in Figure 5 in which the jaws 22, 23 of the clamps 21, 21a are formed from plane, rigid strip metal, rather than from channel sections as illustrated in Figure 5.
The use of channel sections to form the jaws 22, 23 results in the or each angle member 25 being spaced by the height of the channel from the web 12 of the beam 11. In some applications the height of the channel section jaws can prove problematic owing to the proximity of surfaces such as pipework or ducts 38 to the web 12 of the beam 11. Figure 9 illustrates that the jaws 22, 23 can be formed from plane, rigid metal strip such that the angle members 25 are spaced from the web 12 by the thickness of the strip and thus accommodate pre-existing surface pipes or ducts 38 already in close proximity to the web 12 of the beam 11.
In Figure 5 the ends of the upper channels 16 of the lattice beams 14 are shown to overlap the angle members 25 and to be clamped thereto by clamping devices 26. Figure 9 illustrates that the ends of the lattice beams 14 can be provided with right angle cleats 37 as described in relation to the beams 15, the cleats 37 overlying the angle members 25 and being clamped thereto by clamping devices 26.
The planar jaws 22, 23 of Figure 9 are secured to the web 12 by bolts 24 passing through the preformed aperture of the web 12 in the manner described above.

Claims

A structural support assembly for supporting an existing roof structure from an existing I-beam, said structural support assembly comprising a first clamp (21) having a first jaw member (22) arranged to engage one face of the web (12) of the I-beam (11), a second jaw member (23) arranged to engage the opposite face of the web (12) of the I-beam, and, securing means (24) joining the first and second jaw members (22, 23) and extending, in use, through an existing aperture (13) in the web of the I-beam, the jaw members (22, 23) being shaped to span said aperture (13) of the web (12) of the I-beam (11), a second similar clamp (21a) the securing means of which extends through the same, or an adjacent, aperture of the I-beam, characterised by an elongate angle member (25) extending parallel to the I-beam and secured to the first jaws (22) of the first and second clamps (21, 21a) such that one limb (25a) of the angle member (25) is substantially horizontal in use so as to be able to form a support ledge for one end of a subsidiary, roof supporting beam of the structural support assembly in use.
A structural support assembly as claimed in Claim 1 characterised in that said angle member (25) is secured to said first and second clamps (21, 21a) by the securing means securing the first and second jaws of each clamp together.
A method of supporting a structural support assembly from an apertured I-beam said method comprising positioning a first jaw member (22) of a first clamp (21) against one face of the web (12) of the I-beam (11), positioning a second jaw member (23) of the first clamp (21) against the opposite face of the web (12) of the I-beam (11), using securing means (24) joining the first and second jaw members (22, 23) to clamp the jaw members against opposite faces of the I-beam, the jaw members (22, 23) being shaped to span an aperture (13) in the web (12) of the I-beam (11), securing a second similar clamp (21a) in the same way through the same, or an adjacent, aperture of the I-beam, characterised by securing an elongate angle member (25) to the first and second clamps (21, 21a) with the angle member extending parallel to the I-beam whereby the angle member (25) can form a support ledge (25a) for one end of a subsidiary, roof supporting beam of the structural support assembly.
A method as claimed in Claim 3 characterised in that said angle member (25) is secured to said first and second clamps (21, 21a) by means of the securing means securing the first jaw member of each clamp to the second jaw member of that clamp.
A method as claimed in Claim 3 or Claim 4 characterised in that said securing means clamps said jaw members to said web and clamps said angle member (25) to said clamps (21, 21a).
A method as claimed in any one of preceding Claims 3 to 5 characterised in that said jaw members of said clamps (21, 21a) are positioned at right angles to the length of the I-beam (11).
A method as claimed in Claim 6 characterised in that said jaw members abut the upwardly presented face of the lower flange of the I-beam (11).