GB2090901A - Floor formwork - Google Patents

Abstract

Apparatus utilized in the pouring of concrete floors includes:- (a) a pair of spaced and braced substantially rectangular interconnectable modular truss- sections connected together to form a structural unit, each said section at least including (i) a pair of upper and lower longitudinally extending chords (1, 2), (ii) at least a pair of longitudinally spaced vertically extending connectors (4) serving to connect and space said chords (1, 2) apart, (iii) at least one vertically extending load-bearing member (3), intermediate said pair of vertical connectors (4), secured to the side faces of said chords (1, 2) and also serving to connect and space said chords (1, 2) apart; and (iv) at least one diagonally extending member (5) connected to said pair of chords (1, 2) and located between a said vertical connector (4) and said load-bearing member (3), said diagonal member (5) also serving to space chords (1, 2) apart; (b) a plurality of screw-jacks (10) located below said load-bearing members (3) to support said sections in their operative position and capable of pivotal movement when required; and (c) a plurality of beam members (11) detachably secured to the upper portion of said sections and extending at least from side to side thereof. <IMAGE>

Description

SPECIFICATION Truss shoring system and apparatus therefor This invention relates to a truss shoring method arid an apparatus therefor utilized in the pouring of concrete floors. Such systems and apparatus are already known and the latter basically consist of various braced structural members supporting wooden panels on to which the concrete is poured, such arrangements being termed structural units which, after the floor has set, are removed or "flown" to a higher position in the building being erected. However one disadvantage with these known arrangements has been among others, that the provisions for "rolling" the units out from under a poured and set floor to a position for "flying" have not, for one reason or another, proved to be too satisfactory.Another disadvantage has been that the integers of such units have not been too easily interchangeable so that quite large stocks of integers have had to be maintained. Hence, it is the object of the present invention to overcome the above disadvantages by providing a more universal system and apparatus directed to the pouring of concrete for the particular purpose just described.

According to one broad aspect therefore, the present invention relates to apparatus utilized in the pouring of concrete floors, said apparatus including (a) a pair of spaced and braced substantially rectangular interconnectable modular truss-sections connected together to form a structural unit, each said section at least including (i) a pair of upper and lower longitudinally extending chords, (ii) at least a pair of longitudinally spaced vertically extending connectors serving to connect and space said chords apart, (iii) at least one vertically extending load-bearing member, intermediate said pair of vertical connectors, secured to the side faces of said chords and also serving to connect and space said chords apart; and (iv) at least one diagonally extending member connected to said pair of chords and located between a said vertical connector and said load-bearing member, said diagonal member also serving to space said chords apart; (b) a plurality of screw-jacks located below said load-bearing members to support said section in their operative position and capable of pivotal movement when required; and (c) a plurality of beam members detachable secured to the upper portions of said sections and extending at least from side to side thereof.

According to another broad aspect, the present invention relates to a method of assembling a structural unit employed in the pouring of concrete floors, said method including the steps of (a) connecting at least a pair of substantially rectangular interchangeable modular trusssections together in transverse spaced relation to form a structural unit, each said section at least including (i) a pair of upper and lower longitudinally extending chords, (ii) at least a pair of longitudinally spaced vertically extending connectors serving to connect and space said chords apart, (iii) at least one vertically extending.

load-bearing member, intermediate said pair of vertical connectors, secured to the sides faces of said chords and also serving to connect and space said chords apart; and (iv) at least one diagonally extending member connected to said pair of chords and located between a said vertical connector and said load-bearing member, said diagonal member also serving to space said chords apart; (b) locating a plurality of screw-jacks below said load-bearing members to support said sections in their operative position and capable of pivotal movement when required; (c) detachably securing a plurality of beam members secured to the upper portions of said sections so as to extend at least from side to side thereof; and (d) detachably securing a plurality of panels to said beams so as to receive poured concrete thereon.

The invention is illustrated, by way of example and diagrammatically, in the accompanying drawings, in which: Figure 1 is a side view of a basic modular trusssection; Figure 1 c is a cross-section through the upper chord of a modular truss-section taken on the line 1 c-1 c of Figure 2; Figure 2 is a side view of another modular truss-section; Figure 3 is a side view of an end-piece; Figure 4 is a part end view of an assembled modular truss-section; Figure 5 is a front elevation of an adjustable jack; Figure 6 is a side elevation thereof; Figures 7 and 8 show the jack in its operative and inoperative positions; Figure 9 is an end view of one type of beam member showing a wooden insert in situ; Figures 10 to 1 2 are end views of alternative forms of beam members;; Figure 13 is a plan view of the operative surface of a first type of clamp member that can be utilized in the invention; Figure 14 is a side elevation of the entire first form of clamp; Figure 1 5 is a plan view similar to Figure 13 but of a second form of clamp member; Figure 16 is a side elevation of the second form of clamp;.

Figure 1 7 is a perspective view of the second form of clamp; Figure 1 8 is a perspective view of a third form of clamp; Figure 19 is a similar view of Figure 18 but showing the relationship of the clamp to a pair of superposed profiled structural members; Figure 20 is an elevation of an extension leg; Figure 21 is a side elevation of leg-connecting means; Figure 22 is an end view of two forms of modular truss-sections; Figure 23 is an elevation of a connecting sleeve; Figure 24 is a front elevation of an adjustable clamp with the jaws in a closed position; Figure 25 is a plan view of Figure 24; Figure 26 is a rear elevation of Figure 24; Figure 27 is a plan view of the clamp but showing the jaws in open position; Figure 28 is a further plan view of the clamp in situ;; Figure 29 is a diagrammatic view showing a clamp in situ on a modular truss system; Figures 30 and 31 are perspective views of two forms of splicing or connecting plates; Figure 32 is a side view of an alternate modular truss-section; Figure 33 is a side view of a spandrel extension; Figure 34 is a front view of a part of Figure 33; Figure 35 is a plan view of a part of Figure 33; both Figures 34 and 35 being to a larger scale than Figure 33; Figure 36 is a diagrammatic view of three extensions in situ with two modular truss units; Figures 37 and 38 are side views of alternative forms of fence posts to which a safety fence may be anchored; Figures 39 and 40 ere, respectively, a side and end elevation of an adjustable ceiling roller; Figure 41 is a side elevation of a modular truss unit but showing a celing roller in situ; Figure 42 is a diagrammatic view of a modular unit with ceiling roller and showing a phase in the "rolling" and "flying" operations of the unit; Figure 43 is a plan view of a roll-out stand but with certain integers omitted for clarity; Figure 44 is a rear view of the roll-out stand omitting some integers but including others; Figure 45 is a side elevation of Figure 44; Figure 46 is a front elevation of roller and its support;; Figure 47 is a side elevation of Figure 46; Figure 48 is a plan view of Figure 46; Figure 49 is a perspective view of the roll-out stand with the roller and its support in situ; Figure 50 is a perspective view of the roller and its support; Figure 51 is a side elevation of a bracket suitable for use with a pivot dolly; Figures 52 and 53 are, respectively, a front elevation and a plan view of the bracket shown in Figure 51; Figure 54 is a diagrammatic sketch of the socalled pivot dolly; Figure 55 is a diagrammatic view of the end of a truss-section showing the bracket and dolly in situ; and Figure 56 is a diagrammatic view of the end of a truss-section showing the dolly in situ and applied to an extension leg; Figure 57 is a perspective view of a complete modular truss unit with a spandrel extension; and Figure 58 is a view similar to Figure 57 but omitting the spandrel extension.

Prior to discussing the invention in total, the various components forming the invention will be described in detail in the first place.

Modular Truss-Sections Referring to the drawings and in particular to Figures 1-4, the invention includes a pair of substantially rectangular interconnectable modular truss-sections each of which consist of vertically disposed pairs of upper and lower longitudinally extending truss chords 1,2 each of hollow box-like cross-section spaced apart and connected by load-bearing members 3 also of hollow box-like cross-section extending vertically on the outer sides of said chords, 1, 2 and longitudinally spaced tubular connectors 4 extending vertically between said chords, each said member 3 being intermediate a pair of connectors 5. Diagonally extending members 5 also connect the chords together, at least one of said members 5 being located between each adjacent pair of members 3 and connectors 4.

Cross-braces 6 also transversely connect the diagonal members 5 of one truss-section with those of the opposite truss-section through connection studs 7 carried by the members 5 and, if desired, also connect them together in a horizontal plane through connection studs 8 projecting upwardly from the lower chord 2. The upper chord 1 is, as will be seen from Figure 1 c, provided with a pair of side flanges 9 projecting from either side of its upper horizontal surface.

If desired, the end of each modular trusssection may be provided with an end-piece such as that shown in Figure 3 and, as will be appreciated, the truss-sections of each modular unit are connected in end-to-end (or longitudinal) relation by means of splice plates (Figures 30 and 31) bolted to the upper and lower chords 1,2 of a pair of end-to-end abutting truss sections.

Screw-Jacks The invention also includes the use of special screw-jacks which will now be described in detail with reference to Figures 5-8 of the accompanying drawings.

Referring to Figures 5-8 of the drawings, the load-bearing adjustable screw-jack includes an internally bored housing indicated generally at 10 formed of cast aluminum, said housing having a pair of spaced cheeks 11 r (see Figure 6) integrally connected at their lower end to a main body portion 12 and, intermediate the latter and their upper end, by a pair of transverse saddle members 13. The main body portion 12 contains said bore in which a cooperating threaded jackscrew 1 4 is axially movable. The upper end of the jackscrew is provided with a captive limiting ring 1 5 and the lower end of said jackscrew is secured to a loadbearing member or base-plate 16. It will be appreciated that said ring 1 5 and base-plate 1 6 together form means on the jackscrew to limit the amount of axial movement of said jackscrew in either axial direction thereof.

Disposed about, and in threaded connection with, the jackscrew 14 is a cast ductile iron locknut, indicated generally at 17, provided with a pair of diametrically opposed finger-wings 1 8 to facilitate its adjustment on the jackscrew, as well as with a diametrically opposed pair of drainage slots 19 which permit rain to exit from the unit.

The lower end of the main body portion 12 converges towards its central longitudinal axis so that the compressive forces of the load supported by the adjustable jack are directed and channeled towards the central longitudinal axis of the jackscrew for the maximum efficiency of the device.

The adjustable jack is provided with a pin 20 connected to one of the cheeks 11' by means of a chain 21, said jack being capable of pivotal connection to any suitable supporting member such as, for example, a said load-bearing member 3 or to be located under an extension thereof of the truss system, through the intermediary of a pivot pin 22 passing through holes 23 formed in the upper end of the cheeks 11', said pin also passing through the member 3 or extension leg and being detachably held in place by nuts 24.

The cheeks are also provided with a first set of holes 25 and ears 26 in which holes 27 are bored.

In practice, pin 20 is passed through holes 25 and the member 3 when the adjustable jack is in operative position (see Figure 6). However, when it is desired to swing the jack from operative to inoperative position (see Figure 7), pin 20 is removed from holes 25 and the jack pivoted upwardly about pivot pin 22 until the ear 26 lies behind the member 3, whereupon the pin 20 is inserted in said holes 27 to maintain the jack in its operative position.

The lower end of the main body 12, as well as tapering towards the central longitudinal axis, is also stepped as at 28 so as to be accommodated within the adjacent upper central surface of the locknut 1 7. By the same token, the upper end of said main body is of larger diameter than the central bore adapted to receive the jackscrew 1 4 in order the form a seating 29 for the limiting ring 1 5 when said jackscrew is in its lowermost position.

Beam Members The invention also includes the use of various types of beam members such as, for example, those shown in Figures 9-12 of the accompanying drawings although the said beams may also be of the type described and claimed in British Patent No. 1,501,783 published on February 22nd, 1978.

Referring then to Figures 9-12 of the drawings, and in particular to Figure 9, the beam member 11 shown therein consists of an elongated channel member presenting an upper chord, indicated generally at A, a lower chord indicated generally at B and chord connecting means or web (indicated generally at C) intermediate said chords A and B.

The upper chord defines a channel indicated generally at D which is substantially U-shaped in cross-section and which is formed by a pair of opposed side walls 30 connected by a bottom wall 31. The upper end of each side wall terminates in an outwardly extending flange 32 extending normal thereto.

The lower chord B is defined by a pair of lower flanges 33 parallel with, but spaced from, the flanges 32.

The beam includes a slot 34 of substantially T-shaped cross-section located in the general area of the junction of the web C and the lower chord B and which slot is adapted slidably to receive a bolt-head 35 of a slidable clamp (not shown) which does not form any part of this invention but which can, in known manner, clamp a beam to another and adjacent structural member.

The free end of the each flange 32, 33 terminates in a stub flange, indicated generally at 36, profiled by a pair of spaced surfaces 37, 38 portions of which at least extend substantially normal to the longitudinal axis of the web C and which surfaces terminate in a pair of converging surfaces 39, 40 so as to present each stub flange 36 with a substantially conical cross-section.

An insert 41 (which can be of wood) is forced into the channel D and detachably secured therein by any suitable means such as nails (not shown).

Plywood panels P or dimensioned lumber are then laid on the inserts and nailed thereto so as to support the poured concrete.

In the form of invention shown in Figure 10, it will be seen that the surfaces 37 of the stub flanges 36 are much sharper than those shown in the arrangement of Figure 9. In other words, they are much closer to extending at 900 to their associated flanges 32 and 33. Other than that small difference, the second alternative form of the invention is the same at that described above and illustrated in Figure 9.

In the arrangement shown in Figure 11, the beam member omits the T-shaped slot 34 but the thickness of the web C increases, at 42, towards the lower chord B in the general area of the junction of the web and said lower chord.

The arrangement shown in Figure 12 is similar to that in Figure 11 except that the stub flanges are of the type shown in Figure 10.

In all cases, the structural members are of extruded aluminum and the angle between the converging surfaces 39 and 40 is within the range of 800 to 1000 and preferably 900.

From the above description, it will be appreciated that the particular shape of the stub flanges 36 are such that they will resist damage caused by rough handling or abuse and permit the fastening of two identically flanged members to each other by means of a suitable and complementary friction clamp (to be described hereinafter).

The said flanges 36 also provide gripping surfaces for positive connection and a ready means for the self-centering action of the complementary friction clamp, as well as being completely visible for safety inspections.

Clamps The invention also employs various types of clamps as will now be described.

Referring to the drawings and to Figures 1 3 and 14, the first form of clamp that can be employed in the invention is of two-piece construction the first of which includes a clamp member having inner and outer faces 43, 44 with a threaded portion 45 extending from the inner face. The inner face 43 of the member is provided with a pair of slots the first indicated generally at 46 which (and as will be seen from Figure 14) is of substantially square cross-section and constituted by a pair of opposed surfaces 47, 48 each extending substantially normal to the longitudinal axis of the threaded portion 45 and connected together by a surface 49 which is normal thereto, surface 47 being of lesser depth than surface 48.

The second slot, indicated generally at 50, is constituted by a pair of opposed surfaces 51, 52 (extending substantially normal to the longitudinal axis of shank 45) which are connected together by a pair of converging surfaces 53, 54 whereby said slot 50 is of substantially conical cross-section, surface 53 being shorter (when viewed in crosssection) than surface 54. The angle between said surfaces 53 and 54 is within the range of 800 to 100" and is preferably 900.

Cooperating means (taking the form of a butterfly nut 55 and washer 55' on the threaded portion 45) is also provided.

In operation, and depending upon the particular cross-section of the stub flange of the beam member, the clamp is adjusted on said member whereby the stub flange will be located in the appropriate and complementary slot 46 or 50 and the nut 55 then tightened on the threaded portion 45.

In the second form of clamp, the threaded portion takes the form of a headed, threaded steel bolt 45 (see Figure 16) which passes through a bore 56 (see Figure 1 5) formed in the clamp member. The clamp member is provided with a third slot, indicated generally at 57, which is intermediate and parallel with slots 46 and 50 and co-extensive with the central transverse axis of bore 56.

Hence, the entire assembly includes said steel bolt 45 on which the clamp member is initially slidably mounted, said bolt being provided with a relatively small transverse hole (not shown). In assembling the clamp, once the member has been mounted on bolt 45 so that the outer face 44 is in engagement with the head of the bolt and the third slot 57 is in alignment with the small transverse slot in the bolt, a pin 58 is inserted in said slot and through said hole in bolt 45, said pin thereby positively inhibiting the clamp member from movement and securing it on the bolt.The butterfly nut 55 or any other suitable nut is then screwed on the lower end of bolt 45 so as to entrap the stub flange of the profiled structural member (be it that of the upper-truss chord 1 or that of a beam) between it and the clamp and so as to accommodate a said stub flange, said flanges having the same profiles as either slot 46 or slot 50.

Referring now to Figures 1 8 and 1 9 of the drawings, the third form of clamp includes a pair of members A' and B' which complement one another, including inner and outer faces 43, 44 with an unthreaded bore (not shown but similar to bore 56) extending therethrough. The inner face 43 of each member is provided with the three slots 46, 50 and 57 described above in connection with the second form of clamp.

The entire third assembly includes a bolt 45 on which the first and second clamp members A', B' are initially slidably mounted, said bolt again being provided with a relatively small transverse hole (not shown). In assembling the clamp, once member A' has been mounted on bolt 45 so that the outer face 44 is in engagement with the head of the bolt and the third slot 57 is in alignment with the small transverse slot in the bolt, pin 58 is inserted in said slot and through said hole in bolt 45, said pin thereby positively inhibiting the first clamp member A' from movement and securing in on the bolt. The second clamp member B' is then mounted on bolt 45 whereby its inner face 43 will be opposed to the inner face 43 of clamp member A'.A nut 55 is then screwed on to the free end of bolt 4-5 so as to retain the integers in operative relationship to one another where member B' is slidably and swivelly mounted on the bolt 45. The nut and threaded portion 45 are of steel whereas the clamp members are of aluminum.

In operation, and as shown in Figure 19, either one of each pair of slots 46 or 50 (depending on the profile of the stub flanges of the structural member M) accommodates a stub flange of an adjacent structural member and which flange has substantially the same profile as that of its accommodating slot. A portion of the upper chord or the beam (as the case may be) is accommodated between the inner face 43 of the pair of clamping members A' and B' and is retained in such position by the interacting relationship of the bolt and nut urging the clamping members together.

Construction Thus Far Depending upon the required truss length, mutually opposed pairs of modular truss sections are connected together in spaced-apart relation by the said cross-braces 6 and diagonally extending members 5 and the beam members 11 are then laid in spaced, transverse relation thereto with the clamps securing the stub flanges of the beams to the side flanges 9 of the upper longitudinally extending chords 1.

The plywood panels P are then detachably secured to the wooden inserts 41 of the beams by nails in order to receive the poured concrete.

Extension Legs Should the height of the modular truss-unit be insufficient, primary extension legs 58 of substantially box-like cross-section (Figure 20) can be inserted in the lower ends of the vertical load-bearing members 3 and maintained at the required height by means of open-ended U-bolts 59 (see Figure 21) passing through holes (not shown) provided in the lower ends of the loadbearing members 3 and holes 60 spaced throughout the length of said legs 58. A stirrup bar 61 extending across each U-bolt 59 serves to define a hand-grip and also serves as a limiting stop to prevent said bolts 59 from being overinserted into the cooperating and aligned holes in the legs 58. The screwjacks 10 can, if the extension legs 58 are employed, then be positioned below the lower ends of the primary extension legs 58 in order to support the latter.

The right hand side of Figure 22 illustrates this arrangement.

Should the height of the modular truss unit still be insufficient, connecting sleeves 60' (Figure 23) of substantially box-like cross-section are slidden on to the lower ends of the primary extension legs 58 and the upper ends of secondary extension legs 61' also of substantially box-like crosssection (Figure 22) are slidden into the opposite ends of said sleeves 60 which are then bolted to each pair of primary and secondary legs 58, 61 extending in aligned vertical relationship.

Vertically spaced pairs of hingeable clamps 62 (left-hand side of Figure 22) are secured to each vertically aligned pair of legs 58, 61.

Hingeable Clamps The clamps 62 will now be described with reference to Figures 24-29 of the accompanying drawings.

The clamps 62 utilized for the bracing of the legs 58 and 61' must be of a design such that they can readily be applied to said legs as well as permitting quick and easy connection of secondary cross-braces 6'.

Each clamp 62 includes a pair of members 63, 64 pivoted together at 65 and each having threaded means 66 projecting therefrom. In operation, the members 63, 64 are pivoted away from one another (see Figure 27) so as to permit the clamp to embrace an extension leg 58 or 61' and to be tightened thereon. Aperatured ends of transverse and longitudinal cross-braces 6' (Figure 29) are then secured to the clamps 62 by the threaded means 66. The screwjacks 10 can then be mounted to the lower ends of the secondary extension legs 61.

Longitudinal Connection Longitudinally aligned modular truss-sections are connected together by means of pairs of the upper and lower splice plates 67 shown in Figure 30.

Drop-Splice Plates In cases where the underside of the floor to be poured is non-planar, longitudinally aligned modular truss-sections of different heights must be employed. However, in this case, whereas the lower chords 2 are longitudinally aligned, the upper chords 1 are not, so that angled or dropsplice plates 68 (Figure 31) must be employed to connect said aligned sections together and such an arrangement of truss-sections is shown in side view in Figure 32.

Spandrel Extension Often as not, it is required to provide the outer perimeter of a floor with a depending spandrel which is of greater depth than the average depth of the floor, or, alternatively, with one or more depending beams also of greater depth than that of the floor. Hence, special staging is required and by experience, it has been found that the present invention provides this long felt want quickly and in a manner which the required number of integers are kept at a minimum and with very little labour required to erect such an extension. Moreover, as the modular truss units are "flown", after the poured floor has set, to a higher location, it is extremely advantageous to arrange for the extension to form part of such a unit whereby it, too, may be simultaneously flown without dismantling and further "set-up".Refcrence should now be made to Figures 33-36 of the accompanying drawings.

The extension, indicated generally at E, projects from one end of the modular truss unit and includes pairs of vertically disposed upper and lower chords 68, 69 spaced apart by vertical side members 70 each of the latter being disposed between a pair of diagonal side braces 71.

Preferably, the overall length of each lower chord 69 is less than that of the upper chords, 68 and the upper surface of the latter is provided with side flanges 9' (see Figure 34).

The inner ends of the upper and lower chords 68, 69 of hollow box-like cross-section (see Figure 34) are provided with pairs of side plates 72 welded at one end thereof, to the sides of vertical end connectors 73.

Each pair of plates 72 is adapted to embrace an associated vertically extending and bored connector 74 of hollow box-like cross-section and provided with horizontally extending stub extensions 75. Bolts 76 are adapted detachably and adjustably to secure the side plates 72 to the connectors 74 and the extensions 75 are adapted to project into the upper and lower primary chords 1,2 of the modular truss unit. The extensions 75 are retained in situ within the chords 1, 2 by bolts (not shown) passing through holes 77 (Figure 35) in the extensions and corresponding holes (also not shown) formed in the sides of said upper and lower chords 1, 2.

It will thus be apparent that the spandrel extension E is vertically adjustable on the connectors 74 so that its upper horizontal surface can be varied in relation to the upper horizontal surface of the adjacent and connected modular truss unit.

A plurality of cross-beams 11 such as, for example, those described and claimed in British Patent No. 1,501,783 published February 22nd, 1978 or that shown in Canadian Patent No. 1 ,045,348 or those shown in Figures 9-12 herewith (all of which beams include wooden inserts to which the plywood panels P can be nailed) are placed in spaced relation to one another and extend from one upper chord 68 of the spandrel extension to the other in order to support the staging required to pour the spandrel S. Obviously, the free portion of the plywood panels P (to the left as viewed in Figure 33) forms a walkway W which will support a number of workmen and the ancillary equipment required in the pouring of a spandrel S which projects and depends from the outer perimeter of the floor F and which is of greater depth than the latter.

The extension E is also capable of bearing vertically extending fence posts which serve to carry a safety fence as will be described hereinafter. Moreover, and if desired, the lower chords 69 may carry detachable or integral hingeable vertical supports 78 and the lower ends of the latter may be supported by any suitable and vertically adjustable jack means.

Referring now to Figure 36, it will be seen that the invention can also be applied to a pair of spaced and longitudinally aligned modular trusses in order that a pair of mutually disposed spandrels S can be poured at the ends of a floor and a further extension, via a filler panel FP may also connect the pairs of units together in order that a central and depending beam can be poured.

Safety Fence Obviously, and for safety purposes, a safety fence must be provided in order to prevent workers from falling. This can be achieved in two ways. The first is to provide fence post brackets 78' (see Figure 37) of box-like cross-section secured to extensions 79 which are adapted to be placed alongside the outer ends of the upper chords and bolted thereto. The brackets 78' are adapted to receive and support vertical timber posts 80 to which horizontal timber rails 81 are attached and which extend from at least one side of a truss-unit to the other. The second alternative, is to provide vertical steel posts 82 (Figure 38) which, at their lower ends, are hingeably connected to extensions 83 capable of being slidden into the outer ends of the upper chords and bolted thereto.Each post 82 carries at least a pair of vertically spaced hoops 84 to which a preformed mesh safety fence 85 (see Figures 57 and 58) can be detachably secured, such a type of fence being described and illustrated in Canadian patent No. 906,324 which issued on August 1 sot.

1 972.

Ceiling Roller Assembly After the floor has been poured, and the concrete set, it is then necessary to remove the unit from beneath the poured and set floor and to "fly" it to a higher location by a crane in order that a further floor may be poured upon it. Before "flying" however, the unit must be "rolled" outwardly so that it projects a predetermined distance beyond the perimeter of the floor so that the crane can be connected to it. However, before "rolling" can occur, the height of the unit must be reduced. This is done in various ways, i.e. through the use of hydraulic or mechanical jacks, cranes, etc.

It is possible, of course, that the particular shape of the building will require the utilization of the ceiling roller assemblies 86 as will now be described. The use of such assemblies ensures that the poured and set floor immediately above the modular unit will not be damaged during a rolling operation and, moreover, will permit the modular unit to be rolled out, without tipping, beyond its fulcrum point due to the surface engagement between the ceiling rollers 88 and the underside of said poured and set floor.

Reference should now be made to Figures 39-42 of the accompanying drawings.

It will be seen that the assembly 86 includes a vertically adjustable support 87 the upper end of which carries a roller 88, the support 87 being mounted in a holder 89 having an ear 90 capable of insertion in the open end of a top chord 1 of the truss-unit. The support 87, and hence the roller 88, is maintained 7t the desired height by means of a bolt 91, passing through corresponding holes formed in said support and the holder 89. The holder 89 is maintained within the end of the associated upper chord 1 by means of a bolt 92.

Before "rolling" can occur, however, the modular unit supporting the poured and set floor must be lowered on to suitable dollies or floor rollers (to be described hereinafter) so that the ears 92 of the ceiling roller assemblies can be inserted into the open end of the associated upper chords 1 whereupon the supports 87 are vertically adjusted in their holders 89 so as to bring the rollers 88 into surface engagement with the underside of the poured and set floor. The inner end of the unit is then secured to any suitable location by means of what is known in the trade as tie-back or safety lines.

The unit is then pushed outwardly from the building past its fulcrum-point where all four slings (Figure 42) are placed around the upper chords 1 and connected to the crane 94 during a one-step crane operation rather than the previously required two-step crane operation. The unit is then rolled out fully by the crane and "flown" upwardly to a higher location.

Roll-Out Stand As has been stated above, after the floor has been poured and the concrete set, it is then necessary to remove the unit from beneath the poured and set floor and to "fly" it to a higher location by a crane in order that a further floor may be poured upon it. Before "flying" however, the unit must be "rolled" outwardly so that it projects a predetermined distance beyond the perimeter of the floor so that a crane can be connected to it. However, before "rolling" can occur, the height of the unit has to be reduced.

This is done in various ways, through the use of hydraulic or mechanical jacks or other means as will now be described.

In the first instance, the screwjacks 10 and the extension legs 48 must either be removed or pivoted out of the operative position but, as will be appreciated, this cannot be done until the unit is adequately supported by temporary means such as hydraulic or mechanical jacks, etc. which will lower the complete truss panel onto prepositioned roll-out stands or floor rollers which will now be described in detail with reference to Figures 43 to 50 of the drawings The stand, indicated generally at 95 includes a base frame 96 provided, on one side thereof, with a pair of handles 97 and on the opposite side with a mutually opposed pair of wheels 98 which are so arranged that when the stand is in operative position they will not be in frictional contact with the supporting surface.The base frame 96 serves to support a vertically extending central post 99 of hollow box-like section one side of which is provided with a horizontal movable locking lug 100. Angulated cross-straps 101 extend upwardly from the corners of the frame 96 to the post 99 to as to brace the latter. An extension 102, provided with a plurality of vertically spaced holes 103 in one of its side faces, is arranged so as to be vertically adjustable within the post 99 and maintained at the required height by the lug 100 entering a selected one of said holes 1 03. The upper end of the extension 102 has a horizontal plate 104 three side edges of which are each provided with a turned-over detent 1 05.

A roller 106 and its support plate 107, although shown in Figure 42, is shown in greater detail in Figures 46-48 where, as will be seen, the plate 107 is provided with pairs of holes 108, 109 of different diameters and a handle 110.

Hence, and for a "rolling-out" operaton, and after the winch cables 93 have been secured to the upper chord 1 of the truss unit and the inner end of the latter has been secured to any suitable location, a plurality of roll-out stands 95 are wheeled into position beneath a lower chord 2 by an operator grasping the handles 97 and tilting the stand so that the wheels 98 will be brought into contact with the supporting surface. Prior to this, however, the roller support plate 107 will have been slidden on to plate 104 and retained in place by reason of the detents 105 overlying and gripping said support plate 107.

The extension 102 is then raised and locked at the desired height by the locking lug 100. When lowering the truss panel by hydraulic or mechanical jacks, etc. the periphery of the roller 106 is brought into engagement with the underside of the lower chord 2 and the latter will then be accommodated between a pair of spaced cheeks 111 located at either end of said roller 106. This is shown in Figure 36.

The jacks 10 and extension legs 58 having been removed completely or pivoted to their nonoperative position thereby allow the unit to be pushed or"rolled" outwardly from the building until it approximately reaches its fulcrum point, where the slings 93 are placed around the upper chords 1 and connected to the cable 94 of the crane whereupon said unit is "rolled" fully outwardly where the crane can fly the unit upwardly to a higher location.

If the distance between a previously poured floor and that just poured above it is such as to preclude the use of the roll-out stands 95, the rollers 106 and support plates 107 can be removed from the said stands and placed on the floor beneath the lower chords 2 so that the latter will eventually be supported by said rollers 106 as is shown in Figure 42 to permit "rolling".

Inasmuch as the holes 108,109 in the support plate are of different diameters, a safety feature has been provided which ensures that the plate 54 will always be secured in its correct operative position.

From the above description it will be appreciated that not only can a roller 106 operate in conjunction with an associated roller stand 95 but it can also be separated therefrom and employed independently.

Pivot Dolly From time to time, and due to various factors such as, for example, obstructions, it is required to move the modular truss unit in a horizontal plane but other than in a straight longitudinal axis as just described. Accordingly, the present invention envisages the use of what can be termed a "pivot dolly".

In other words, it is sometimes required for a truss unit to be moved sideways or transversely in a horizontal plane, prior to a "rolling-out" operation, owing to e.g. a projection depending from the underside of the upper (and recently poured and set floor) and this is achieved through the pivot dolly and/or bracket about to be described.

Referring then to Figures 51-53 of the drawings, a support bracket, indicated generally at 112 and of hollow box-like section is provided.

The upper end of the vertically extending main body section 11 3 is provided with a pair of spaced upper cheeks 114 adapted, when in situ to embrace a tubular connector 4 and to be detachably secured in this operative position by means of nut and bolt means 11 5 which tightens the cheeks to the connector 4. The lower end of the main body section 11 6 of bracket 11 5 is provided with a lower support plate 11 7 provided with a front stop 11 8.

The so-called pivot dolly is indicated generally at 11 9 in Figures 54-56 and has a wheeled carriage provided with a primary handle 120, a threaded vertically adjustable support column 121 having an upper end 122 of substantially square cross-section, and a secondary handle 123.

Assuming that the truss-sections do not employ an extension leg 58 and it is desired to move a section transverse to its length, a plurality of support brackets 112 would be detachably secured (by the clamping action of the cheeks 114), to associated connectors 4 as is shown in Figure 55 where, it will be noted, the underside of the lower chord 2, will rest upon the lower support plate 1 1 7 and be inhibited from transverse movement by the main body section 11 3 in one direction and the stop 11 8.

Pivot dollies 109 would then be moved into place so that, upon threaded adjustment, the upper end 122 of each column 121 would enter the lower end of an associated bracket 112 whereby the lower edge of the main body section 11 3 of the bracket would be supported by the collar 124 or base of the upper end of the column 121.

Once the screwjacks 10 have been pivoted whereby the weight of the truss sections is borne by the dolly, it is possible to move the said truss sections in any direction in a longitudinal plane.

In the case where extension legs 58 form part of the truss unit, the support brackets 112 are not used when it is desired to move said unit. In such a case, the main weight of the unit is borne by another type of dolly, known as a high-rise dolly (not forming part of this invention) so that the screwjacks 10 supporting the extension legs 58 can be removed entirely. Removal of the jacks 10 enables the open lower ends of the extension leg 58 to be revealed so as to receive the upper end of a pivot dolly 119 as is shown in Figure 56 whereby the truss unit can be moved in any direction in a horizontal plane.

Method As has already been stated, the "rolling-out" is slightly different, depending upon whether the screwjacks 10 are pivotally mounted to the lower ends of the load-bearing members 3, or support the lower ends of the primary extension legs 58, or support the lower ends of the secondary extension legs 61 and whether the three types of unit just described are provided with one or more spandrel extensions E.Accordingly, the sequential steps of the rolling-out and flying procedure comprise:- (i) Unit without extension legs (a) placing at least two hydraulic dollies of any suitable low-rise type (not shown) beneath the lower chords 2 of the modular unit and supporting the latter thereon; (b) securing the inner end of the unit to any suitable location by means of cables (not shown) and known in the trade as tie-back or safety lines in order to ensure that the unit is not rolled outwardly too far; (c) slackening the jacks 10 (pivotally mounted to the lower ends of the load-bearing members 3), pivoting them upwardly and thereafter securing them in their non-operative position as described above; (d) placing at least four rollers 106, two either side, under the lower chords 2;; (e) causing the hydraulic jacks to lower the modular unit until it is supported on said rollers 106; and (assuming that the ceiling roller assemblies 86 are not utilized) (f) pushing the unit outwardly from the building until it approximately reaches its fulcrum-point where the slings 93 are placed around the upper chords 1 and connected to the cable 94 of a crane whereupon said unit is pushed (or "rolled") fully outwardly where the crane will "fly" the unit upwardly to a higher location.

It is possible, of course, that the particular shape of the building will require the utilization of the ceiling roller assemblies 46 as will now be described. The use of such assemblies ensures that the poured and set floor immediately above the modular unit will not be damaged during a rolling operation and, moreover, will permit the modular unit to be rolled out, without tipping, beyond its fulcrum point due to the surface engagement between the ceiling rollers 88 and the underside of said poured and set floor. If the use of the assemblies 86 is required, then an additional step (e') will be required i.e.

(e') inserting each ear 90 of each assembly 86 into the open inner end of each upper chord 1.

(ii) Unit with primary extension legs (a) placing at least two hydraulic jacks of any suitable high-rise type beneath the lower chords 2 of the modular unit and supporting the latter thereon; (b) placing at least four roll-out stands 95 under the lower chords 2 at a pre-determined locations and at pre-set elevations; (c) slackening the jacks 10 supporting the primary extension legs 58 and removing and securing them in any suitable location on the modular truss unit; (d) removing the U-bolts 59 connecting the primary extension legs 58 to the load-bearing members 3 and pushing the legs 58 upwardly until they are contained within the mernbers 3 when said bolts 59 are re-inserted to retain said legs 58 in their inoperative position;; (e) if the type of dolly 95 is not employed, placing at least four floor rollers 106 (Fig. 50), two either side, under the lower chords 2; (f) causing the hydraulic jacks to lower the modular unit until it is supported on said rollers 106; (g) if the ceiling roller assemblies 86 are employed, inserting the ears 90 of said assemblies into the open inner end of each upper chord 1; (h) securing the inner end of the unit to any suitable location by means of a tie-back or safety line; and (i) pushing the unt outwardly and flying it in accordance with step (f) of method (1) described above.

It will be appreciated that step (b) of method (ii) will not be required if floor rollers 106 of the type shown in Figure 50 are employed because the lower chords 2 will be sitting on the rollers 106 thus enabling the unit to be rolled outwardly on said floor rollers, the use of which depends upon the height between the two adjacent floors and any possible obstructions in the roll-out path.

Quite obviously, by making use of said step (b) a distinct saving in manpower time is achieved.

(iii) Unit with both primary and secondary extension legs The height between the two adjacent floors dictates whether primary extension legs 58, each having at least one secondary extension leg 61', are used. However, when such legs are used, the height is too great for the utilization of the highrise hydraulic jacks so that the lowering procedure is different i.e. the modular unit is supported from above through the intermediary of winches located on the floor above and cooperating cables passing through holes formed in said floor and fastened to the truss unit. The holes are constituted by sleeves around which the concrete of the upper of the two floors is poured during a pouring operation and the winches are placed in position on said upper floor when the latter has set.The lowering procedure would then include the following steps: (a) securing the winch cables to the upper chord 1 of the modular truss unit; (b) removing the pivot jacks 10 supporting the lower ends of the secondary extension legs 61 ' and securing said jacks 10 to the truss unit; (c) removing the cross-braces 6', clamps 62, sleeves 60 and secondary extension legs 61'; (d) removing the U-bolts 59 connecting the primary extension legs 58 to the members 3 and pushing said legs upwardly until they are contained within said members 3 when said bolts 59 are reinserted to retain the legs 58 in their inoperative position; (e) either placing roll-out stands under the lower chords 2 of the unit or the floor rollers 106 (Fig. 50) on the floor under said chords;; (f) lowering said modular unit, by means of the winches, down on to said roll-out stands 95 or the said floor rollers 106; (g) inserting the ceiling roller assemblies 86 (if required) into the open inner ends of the upper chords 1 of the truss unit; (h) securing the inner end of the unit to any suitable location by means of tie-backs or safety lines; (i) disconnecting the winch cables from the truss unit; and (j) pushing the unit outwardly and flying it in accordance with step (f) of method (i) described above.

If, due to a projection depending from the underside of the upper floor, it is required to move a truss unit sideways or transversely in a horizontal plane prior to a rolling-out operation, this can be achieved by the use of the dolly 11 9 shown in Figure 54 and the positioning of such a dolly depends upon whether primary extension legs 58 are used or not.

Assuming that primary extension legs 58 are not employed and it is required to move the trussunit sideways, the support brackets 11 2 are detachably secured to the tubular connectors 4 with the support plates 61 located beneath the lower chords 2, whereby after the jacks 10 have been pivoted upwardly and secured in their nonoperative position, the pivot dollies 11 9 can be positioned beneath the brackets 11 2 and vertically adjusted until their upper ends 1 22 are accommodated within the open lower ends of said brackets 11 2. Thus, as the wheeled dollies 11 9 are moved, the truss unit will follow due to being supported by said dollies.

Alternatively, and assuming the primary extension legs 58 are employed and have been slidden upwardly and secured within the loadbearing members 3, the dollies 119 can be positioned beneath the open ends of said legs 58 and vertically adjusted until their upper ends 11 2 are accommodated within said open ends ancl thereby support the modular truss unit for sideways movement.

Finally, it is to be noted from the drawings that the diagonal members 5, of each associated pair thereof, extend downwardly towards one another and to their point of connection with the lower chord 2, either from adjacent the upper end of a vertical load bearing member 3 or from an adjacent upper end of a tubular connector 4. This means that the modular truss unit can be supported at the points of intersection of said members 3 and connectors 4 with the lower chord 2, as well as at the points of intersection of the diagonals 5 with said chord 2, said points preferably being 2'-6" apart. This is distinctly advantageous over known prior art where the load-bearing members are spaced 5'-0" and 10'-0" apart and the diagonals meet at their point of connection with one another as well as their intersection with the upper chord.This is distinctly advantageous because of the whip and play of the prior art units during "rolling" operations due to the great distance between the lower connection points and particularly when such a unit assumes the position such as that of the instant invention in Fig. 42.

The present invention is also advantageous in that in the arrangement shown and described above, the substantially rectangular truss sections permit the modular truss units formed thereby to be spliced together at their extremities whereas, in at least one known arrangement, the units are spliced together at mid-span because the sections are substantially parallelogram shaped due to the chords being of different lengths.

Moreover, as the load-bearing members 3 of the present invention are box-like cross-section, as opposed to known art, where they are of I-beam construction, the unit is much stronger and has a greater rigidity.

Claims (47)

1. Apparatus utilized in the pouring of concrete floors, said apparatus including: (a) a pair of spaced and braced substantially rectangular interconnectable modular trusssections connected together to form a structural unit, each said section at least including (i) a pair of upper and lower longitudinally extending chords (1, 2), (ii) at least a pair of longitudinally spaced vertically extending connectors (4) serving to connect and space said chords (1, 2) apart, (iii) at least one vertically extending loadbearing member (3), intermediate said pair of vertical connectors (4), secured to the side faces of said chords (1,2) and also serving to connect and space said chords (1, 2) apart; and (iv) at least one diagonally extending member (5) connected to said pair of chords (1,2) and located between a said vertical connector (4) and said load-bearing member (3), said diagonal member (5) also serving to space chords (1,2) apart; (b) a plurality of screwjacks (10) located below said load-bearing members (3) to support said sections in their operative position and capable of pivotal movement when required; and (c) a plurality of beam members (11) detachably secured to the upper portion of said sections and extending at least from side to side thereof.

2. Apparatus according to Claim 1 including a pair of diagonal members (5) between a said vertical connector (4) and said load-bearing member (3).

3. Apparatus according to Claim 2 wherein each said load-bearing member (3) is hollow and is of substantially box-like cross-section.

4. Apparatus according to Claim 3 including a detachable extension leg (58) of substantially boxlike cross-section slidably mounted in said loadbearing member (3).

5. Apparatus according to Claim 3 wherein each said screwjack (10) is pivotally mounted on an associated said load-bearing member (3) adjacent its lower end, and is capable of being pivoted out of its normal operative position below said load-bearing member (3) and locked in an inoperative position.

6. Apparatus according to Claim 5 wherein each said screwjack (10) has an internally bored housing; a cooperating threaded jackscrew (14) axially movable in said bore; a load-bearing plate (1 6) on the end of said jackscrew (10) remote from said housing; a locknut (17) in threaded engagement with said jackscrew (14) and adapted to cooperate with a selected end of said housing thereby to lock said jackscrew (10) in a desired axial relationship with said housing; said housing, adjacent said selected end, converging towards its central longitudinal axis so as to direct and channel the compressive forces of said load towards the central longitudinal axis of said jackscrew (10).

7. Apparatus according to Claim 6 wherein the end of said housing remote from said selected end includes means (22, 24) whereby said jack (10) can be pivotally mounted to a said load bearing member (3) and means (20) for locking said jack (1) to said member (3) when in operative position.

8. Apparatus according to Claim 7 wherein said locking means (20) is also capable of locking said jack (1 0) in its inoperative position.

9. Apparatus according to Claim 8 wherein said housing includes a pair of cheek members (11') interconnected adjacent one end thereof by a main body portion which converges from said one end of said cheek members (11') towards the central longitudinal axis of said housing.

10. Apparatus according to Claim 9 wherein said cheek members (11') are interconnected by a pair of transverse saddle members (13) adjacent said main portion.

11. Apparatus according to Claim 10 wherein said load-bearing plate is constituted by a baseplate (16) secured to said remote end of the jackscrew (10), a threaded locating ring (15) being fast on said opposite end of the jackscrew, said plate (16) and said ring (15) limiting the amount of movement of said jackscrew (10) in either axial direction thereof.

12. Apparatus according to Claim 11 wherein said locknut (17) is provided with a pair of diametrically opposed drainage slots (19) and a pair of diametrically opposed finger-wings (18) to facilitate adjustment of said locknut (17).

1 3. Apparatus according to Claim 12 wherein said means for locking said jack to said supporting member includes a pair of apertures (25) formed in said cheek members (11') and a cooperating locking pin (20) for slidable movement in said apertures (25).

14. Apparatus according to Claim 13 wherein said housing is of cast aluminum, said jackscrew (14) and baseplate (16) are of structural steel, and said locknut (17) is of cast ductile iron.

1 5. Apparatus according to any of the preceding claims wherein said beam members (11) each consist of an extruded, elongated channel member presenting an upper chord (A), a lower chord (B), and chord connecting means (C) intermediate said chords, said upper chord (A) defining a channel (D) substantially U-shaped in cross-section adapted to permit the introduction of a removable insert (41) therein, said channel having a pair of opposed side walls (3) connected by a bottom wall (31), the free end of each said side wall (30) terminating in an outwardly extending flange (32) normal thereto; said chord connecting means (C) comprising a central web extending between said upper and lower chords (A, B); said lower chord (B) being defined by a pair of flanges (33) parallel with, and spaced from, the first-mentioned flanges (32); the free end of each said flange (32, 33) terminating in a stub flange (36) profiled by a pair of spaced surfaces, portions (37,38) of which at least extend substantially normal to the longitudinal axis of said web and which terminate in a pair of converging surfaces (39, 49) so as to present each said stub flange (36) with a cross-section which is substantially conical in cross-section.

1 6. Apparatus according to Claim 1 5 wherein each beam member (11) includes a slot (34) of substantially T-shaped cross-section located in the general area of the junction of the web (C) and the lower chord (B), said slot (34) being adapted slidably to receive the head of a bolt (35) associated with a slidable clamp.

1 7. Apparatus according to Claim 1 5 wherein the thickness of said web (C) increases towards the lower chord (B) in the general area (42) of the junction of the web (C) with said lower chord (B).

1 8. Apparatus according to Claims 1 5-1 7 wherein the angle between the said pair of converging surfaces (37, 38) is within the range of 800 to 1000.

1 9. Apparatus according to Claim 1 8 wherein said angle is 900.

20. Apparatus according to Claims 1 5-19 wherein each said beam (11) is formed from extruded aluminum.

21. Apparatus according to any of the preceding claims including a clamp capable of being detachably fastened to a profiled structural member, said clamp including a threaded portion (45), at least a first clamp member (A') fast on said threaded portion (45), and means (55) cooperating with said threaded portion (45) to urge said first member (A') into its clamping relationship with a complementary portion of said profiled member, said clamp member having at least a first slot (46) of substantially square crosssection, and a second slot (50) of substantially conical cross-section; said slots (46, 50) being adapted to accommodate a stub flange (9, 36) of said structural member and which flange has substantially the same profile as that of its accommodating slot.

22. Apparatus according to Claim 21 including a second member (B') slidably and swivelly mounted on said threaded portion (45) and retained thereon by said cooperating means (55), said second member (B') having slots (46, 50) complementing those in said first member (A') and opposed thereto; a selected one of each pair of said complementary slots (46, 50) accommodating a said stub flange (9, 36) a further portion of said structural member being accommodated between both of said clamping members (A', B') and being retained in such position by the interacting relationship of the threaded portion (45) and said cooperating means (55) urging said clamping members (A', B') towards one another.

23. Apparatus according to Claims 21 or 22 wherein each first slot (46) is constituted by a pair of opposed surfaces (47, 48) each extending substantially parallel to the longitudinal axis of said threaded portion and connected, at one end thereof, by a surface (49) which is normal thereto, one (47) of said pair of opposed surfaces being of lesser depth than the other (48).

24. Apparatus according to Claim 23 wherein each second slot (50) is constituted by a pair of opposed surfaces (51, 52) each extending substantially parallel to the longitudinal axis of said threaded means and connected together, at one end thereof, by a pair of converging surfaces (53, 54) whereby a slot (50) of substantially conical cross-section is presented, one (54) of said converging surfaces being longer than the other.

25. Apparatus according to Claim 24 wherein the angle between said pair of converging surfaces (53, 54) is within the range of 800 to 100 .

26. Apparatus according to Claim 25 wherein said angle is 90".

27. Apparatus according to Claim 26 including at least one hole in said threaded portion (45) transverse to said longitudinal axis, a third slot (57) in at least said first member (A') intermediate said first (46) and second (50) slots and parallel therewith, and a detachable pin (58) located in said third slot (57) and passing through said threaded means (45) detachably to secure said first (A') member to said threaded means (45).

28. Apparatus according to Claim 27 wherein the cooperating means is a nut (55) and wherein the latter and said threaded portion (45) are steel.

29. Apparatus according to Claim 28 wherein said clamp members (A', B') are formed from aluminum.

30. Apparatus according to any of Claims 4-29 including an adjustable clamp (62) for use with said extension legs (58), said clamp having a pair of hingedly connected members (63, 64) adpated to embrace a primary said extension leg (58) and to be detachably clamped thereto, each said hinged member (63, 64) having threaded means (66) adapted to receive the apertured end of an associated bracing member (6') which is detachably secured thereto, certain of said bracing members (6') connecting adjacent pairs of said primary extension legs (58) together.

31. Apparatus according to Claim 30 including secondary extension legs (61') each of substantially box-like cross-section, certain of said bracing members (C') connecting adjacent pairs of said primary extension legs (58) together, and others of said bracing members (6') connecting opposite pairs of said secondary extension legs (61') together.

32. Apparatus according to any of the preceding claims including an extension (E) projecting from at least one end of said structural unit and including pairs of vertically disposed upper and lower truss chords (68, 69), each said pair being spaced apart and connected together by at least a pair of vertically extending side connectors (70, 73); and means (72, 74, 76) for attaching said extension (E) to said one end of the unit, the uppermost horizontal surfaces of said upper chords (68) being lower than the uppermost horizontal surfaces of said unit and being adapted to support a walkway (W) and permitting a spandrel to be poured, said spandrel having a greater depth than the depth of said concrete floor.

33. Apparatus according to Claim 32 wherein said attachment means include a pair of side connectors (74) each adjustably and detachably secured to adjacent ends of said upper and lower longitudinally extending chords (68, 69) said extension (E) being detachably secured to said side connectors (74) whereby the distance between said walkway (W) and the upper horizontal surface of said upper and lower longitudinally extending chords (1, 2) can be varied.

34. Apparatus according to Claim 32 wherein at least the ends of said upper and lower longitudinally extending chords (1,2) are of hollow box-like cross-section and said attachment means includes pairs of side plates (72) secured to, and extending from, an end of the truss chords (66, 69) of said extension (E). said side plates (72) being detachably and adjustably secured to said pair of side connectors (74); and upper and lower horizontally extending stub extensions (75) on the ends of said connectors (74) capable of being slidden into the adjacent and hollow ends of said upper and lower longitudinally extending chords (1, 2) and to be detachably secured therein.

35. Apparatus according to either Claims 33 or 34 wherein the length of the upper truss chord (68) of said extension (E) is greater than the length of the lower truss chord (69) thereof and said chords are additionally connected together by a pair of diagonal side struts (71).

36. Apparatus according to Claim 35 wherein the outer end of said extension (E) is adapted detachably to support a plurality of fence posts (82) of a safety fence (85).

37. Apparatus according to Claim 33 wherein said extension (E) interconnects the ends of a pair of adjacent and aligned truss units.

38. An extension according to Claim 37 including supports (78) adjustably and detachably secured to the lower truss chords (69) of said extension (E) to support the latter.

39. Apparatus according to any of the preceding claims including at least a pair of vertically adjustable ceiling rollers (85) each projecting from an associated holder (89) capable of insertion into an open end of an associated said upper longitudinally extending chord (1) and detachable securement therein, said rollers (85) being capable of surface engagement with the underside of a poured and set floor above said sections.

40. Apparatus according to Claim 39 wherein each said roller (85) is mounted on the upper end of a support (87) which is adjustable within an associated said holder (89).

41. Apparatus according to any of the preceding claims including a roll-out stand (95) having a roller (106) mounted on a vertically adjustable member (102), said roller (106) being adapted to support an associated said lower longitudinally extending chord (2) thereon, and means (98) on said stand (95) for moving the latter, and hence said modular truss section in a defined path of horizontal travel.

42. Apparatus according to Claim 14 wherein said means include a pair of wheels (98) which, when said stand is in operative position, are not in frictional contact with a surface supporting said stand, and at least one handle (97) for tipping the stand (95) to bring said wheels (98) into contact with said surface and to wheel said stand (95) to its said operative position.

43. Apparatus according to Claim 42 wherein said vertically adjustable member (102) is provided with means (105) detachably to retain said roller(106) thereon.

44. Apparatus according to Claim 43 wherein the roller (106) is provided with a pair of mutually opposed side cheeks (1 11) bracketing said lower chord (2).

45. A method of assembling a structural unit employed in the pouring of concrete floors, said method including the steps of: (a) connecting at least a pair of substantially rectangular interconnectable modular trusssections together in transverse spaced relation to form a structural unit, each said section at least including (i) a pair of upper and lower longitudinally extending chords, (ii) at least a pair of longitudinally spaced vertically extending connectors serving to connect and space said chords apart, (iii) at least one vertically extending load-bearing member, intermediate said pair of vertical connectors, secured to the side faces of said chords, and also serving to connect and space said chords apart; and (iv) at least one diagonally extending member connected to said pair of chords and located between a said vertical connector and said load-bearing member, said diagonal member also serving to space said chords apart; (b) locating a plurality of screw-jacks below said load-bearing members to support said sections in their operative position and capable of pivotal movement when required; (c) detachably securing a plurality of beam members to the upper portions of said sections so as to extend at least from side to side thereof; and (d) detachably securing a plurality of panels to said beams so as to receive poured concrete thereon.

46. Apparatus for use in the pouring of concrete floors substantiaily as hereinbefore described with reference to and as shown in the accompanying drawings.

47. A method of assembling a structural unit employed in the pouring of concrete floors substantially as hereinbefore described with reference to the accompanying drawings.