Abstract:
An extruded metal structural component has a hollow generally rectangular section with the sides of the rectangular section adapted to interlock and engage with other structural components of the same cross section. The generally rectangular section includes on one side a shallow “U” shaped channel and the opposite side includes a projecting portion for mating receipt in the “U” shaped channel of a second structural component. The structural component includes a downwardly extending securing flange for engaging and securing connecting members when two such structural components form the top and bottom chord of a structural beam.

Description:
FIELD OF THE INVENTION 
   The present application relates to truss systems used in the construction industry, and in particular, relates to a column hung truss system for forming of concrete floors. 
   BACKGROUND OF THE INVENTION 
   Flying form trusses are used to form concrete floors in multi-story structures. Some flying form truss systems transmit the poured concrete load directly to the floor slabs below and in fast construction cycles, the concrete floor below may not be fully cured. For this reason, reshoring of the lower concrete floor may be necessary to transmit the loads to a slab which is fully cured. Reshoring takes additional time and also limits the access to some lower levels which are effectively cured. 
   To overcome the above problems, it is known to use column mounted flying form truss systems designed to transfer the concrete load to the columns as opposed to the lower floors. Column mounted truss systems allow full access to the lower floors and the follow-up trades can be working on any floors which have been previously poured. With this arrangement, the construction cycle can be reduced. 
   Column mounted flying truss systems are most commonly used with flat slab construction but can accommodate shallow internal beams and spandrel beams. Any projection from the slab soffit increases the stripping distance the support jacks must lower the truss to allow removal. 
   Flying form systems typically use two large I-beams which run parallel to the building support columns with the I-beams being supported by shoring jacks secured to the columns. The shoring jacks are adjustable in height and typically have a roller associated therewith to allow lowering of the I-beams and sliding of the truss out of the formed bay. These I-beams have a series of transverse beams secured to and extending perpendicular to the I-beams. A series of runner beams which typically support a plywood deck are secured and extend perpendicular to the transverse beams. 
   The construction design of the building in combination with the expertise of the contractor typically determine whether a column hung truss system or a shoring frame truss system will be used. Column hung truss systems are often used for condominium and hotel construction, particularly when a short construction schedule is needed. 
   The transverse beams are of a length which is primarily determined by the width of the bays used in the building. The bay width is the distance between the columns. Surprisingly the bay width of different buildings varies substantially and thus different lengths of transverse beams are required. It is known to use composite transverse beams formed using U-shaped channel sections placed in back to back relationship and secured in an overlapping adjustable manner. Typically mechanical fasteners are used to secure the channels to form the appropriate length of transverse beams. It is desirable to produce relatively stiff transverse beams such that the spacing between the beams can be large, thereby reducing the number of transverse beams required and reduce the weight of the system. It is desirable that the overall weight of the flying truss be reduced to ease the movement thereof and to accommodate the crane capacity used for the building construction. 
   The present invention provides improvements to the transverse beams and improvements to truss systems used in concrete forming. 
   SUMMARY OF THE INVENTION 
   An extruded elongate metal component according to the present invention comprises in cross section, a hollow section having a top securing section first and second opposed side securing sections and a bottom securing section. The top securing section includes a recessed bolt slot extending the length of the structural component. The side sections have complimentary shapes with the first side securing section including a recess extending the length of the structural component, the second side securing section includes a projecting section sized for snug receipt in the recess of first side section. The bottom securing section includes at least one downwardly projecting securing flange extending the length of the structural component. 
   According to an aspect of the invention, the extruded elongate structural component is an extruded aluminum alloy component. 
   In a further aspect of the invention, the hollow section of the structural component is of a generally rectangular cross section. 
   In yet a further aspect of the invention, each side section has a series of holes extending therethrough and aligned with the holes through the other side section. 
   In yet a further aspect of the invention, the at least one downwardly projecting securing flange is two downwardly projecting securing flanges disposed in parallel relationship either side of the center line of the bottom section. 
   In yet a further aspect of the invention, the securing flanges include a series of securing holes passing therethrough and spaced in the length of the structural component. 
   In yet a further aspect of the invention, the recess in the first side section is a shallow U-shaped section which dominates the first side section and the projecting section of the side section includes opposed upper and lower shoulders for engaging sides of the shallow U-shaped section. 
   An assembled structural beam, according to the present invention, comprises a top chord and a bottom chord which are mechanically connected by a series of diagonal connecting members. The top chord includes on an upper surface, a longitudinally extending bolt slot. The bottom chord includes on a bottom surface, a longitudinally extending bolt slot. Each of the top chord and the bottom chord have two opposed side surfaces with a shallow channel recess in one side extending the length of the chord, and a complementary projection on the opposite side extending the length of the chord and sized for receipt in the shallow channel recess. Each of the top chord and the bottom chord are extruded components and include a securing flange which cooperates with the diagonal connecting members to secure the top chord to the bottom chord. 
   In an aspect of the structural beam, vertical connecting members are included. 
   In a preferred aspect of the invention, the top chord and the bottom chord of the assembled structural beam are of the same cross section. 
   In yet a further aspect of the invention, the top chord includes a hollow cavity extending the length thereof. 
   In yet a further aspect of the invention, the chords and the diagonal connecting members are extruded aluminum alloy components. 
   In yet a further aspect of the invention, the diagonal connecting members are secured to the chords using mechanical fasteners. 
   In yet a further aspect of the invention, the top chord includes on an upper surface a longitudinally extending bolt slot and the bottom chord includes on a bottom surface, a longitudinally extending bolt slot. 
   The present invention is also directed to a header beam which is adjustable in length. The header beam comprises two beam sections secured one to the other in an overlapping manner. Each beam section is an assembled structure having a cop chord, a bottom chord and a series of connecting members secured thereto between. The top chord and the bottom chord of the beams include interfitting surfaces which maintain longitudinal alignment of the beam sections relative to each other. The beam sections further include a series of holes in the top chord and bottom chords and a plurality of structural fasteners passing through aligned holes in the chords which in combination with the interfitting surfaces, mechanically secure the beam sections. 
   An adjustable in length header beam according to an aspect of the invention, as each of the beam sections being of the same cross section. 
   In yet a further aspect of the invention, the top chord and the bottom chord are of the same cross section. 
   In a further aspect of the invention, the chords are formed by extrusion and each chord has an extending member at one side and a corresponding receiving channel on the opposite side thereof. 
   In yet a further aspect of the invention, the header beam is stackable with like header beams with the interfitting surfaces engaging to partially maintain the stack of beams. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention are shown in the drawings, wherein: 
       FIG. 1  is a perspective view of the column hung flying truss; 
       FIG. 2  is a side view of the column hung truss; 
       FIG. 3  is a partial perspective view of the column mounted jack; 
       FIG. 4  is a perspective view of a beam section; 
       FIG. 5  is an exploded perspective view of part of a beam section; 
       FIG. 6  is a partial perspective view of a beam section supporting a runner beam; 
       FIG. 7  is a side view of two beam sections secured together; 
       FIG. 8  is a partial perspective view showing the securement of the beam sections; 
       FIG. 9  is a sectional view showing two secured beam sections; 
       FIG. 10  shows details of the column jack; 
       FIG. 11  shows details of a support bracket used to secure the beam sections; 
       FIG. 12  is a side view of a secured transverse beam; 
       FIG. 13  shows details of a secured beam section to the support bracket; 
       FIG. 14  shows two trusses at a support column; 
       FIG. 15  shows further details of the column hung jack. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  schematically shows a bay of a building having the flying truss mounted to the columns in preparation for pouring of a concrete floor. The flying truss  2  has two main beams  4  which extend between columns  12  of the building and are supported by the columns by column mounted jacks  9  mechanically secured to the columns. The bay  11  of the building is generally the space between the columns  12 . The main beams  4  have connected to them, a series of transverse beams  6  which are of a composite structure. These transverse beams are generally perpendicular to the main beams  4 . A series of runner beams  8  are attached to the upper surface of the transverse beams  6  and support the plywood deck  14 . Once the reinforced concrete floor  10  has been poured and partially cured, such that it can support its own weight, the flying truss may be lowered on the column jacks  9  and moved out of the bay in preparation for locating between the columns for pouring of the next floor or an adjacent bay. 
     FIG. 2  shows the various elements of the flying truss  2  supported within the bay  11  of the building. 
     FIG. 3  shows various details of the column mounted jack  9 , the main beams  4  and the transverse beams  6 . As shown, the transverse beams  6  are of a composite design and are of a depth which extends below the main beams  4 . The increased depth provides greater stiffness and allows further separation of the transverse beams. The spacing between transverse beams  6  will depend on the concrete load, however, this spacing is typically 64 to 108 inches. This spacing is approximately double the spacing necessary if standard bar joist beams are used to carry the same load. The distance between the aluminum alloy runner beams  8  is 16 to 19 inches depending upon the plywood and the thickness of concrete to be poured. 
   As shown in  FIG. 3 , the runner beams  8  are preferably of an I-beam section with a center channel for receiving a nailer strip. In this way, the plywood deck  14  may be secured by screws or nails to the nailer strip located in the runner beams. 
     FIG. 7  shows details of the composite transverse beam  6 . The composite transverse beam is made of two beam sections  44  and  46  which are mechanically secured by a series of bolt and nut combinations  48 , at the overlapping ends of the two beams. Both the bottom chord and the top chord are mechanically secured using a series of holes in the chord members as generally shown in FIG.  9 . 
   One beam section  44  is shown in FIG.  4 . This beam section includes a top chord  20 , a bottom chord  22  and a series of diagonal bracing members  24  and a series of vertical members  26 . Members  24  and  26  are mechanically secured to the top and bottom chords. Each of the chords is of the same structure and has a series of holes  22  extending in the length of the chords. These holes pass directly through the chords and are used to mechanically fasten two sections, one to the other. 
   A top chord  20  is shown in  FIG. 6 , and has a generally rectangular shaped enclosure  30 , having a top portion  32 , opposed side portions  34  and  36 , and a bottom portion  38 . The top portion  32  includes a longitudinally extending bolt slot  50  used to mechanically fasten the runner beams  8  to the transverse beams  6 . The side portion  34  includes an outwardly extending elongate rail  52  which is sized for receipt in the U-shaped receiving channel  54  in the opposite side  36 . The bottom portion  38  includes downwardly projecting securing flanges  40  and  42  centered either side of the center line of the chord and uses to mechanically secure the diagonal and vertical connecting members  24  and  26 . As shown in  FIG. 5 , the securing flanges  40  and  42  have a series of holes  43  at various points in the length of the chord and is used to fasten the connecting members by means of bolts  45 . 
   The flanges  40  and  42  are positioned inwardly of the sides  34  and  36  with the entire mechanical connection of the connecting members  24  and  26  located in a non interference position when two sections are secured, one to the other, as shown in  FIGS. 7 ,  8  and  9 . The side portions of the enclosure  30  are designed to mate and form a mechanical connection opposing racking of the sections when a load is carried by the transverse beam  6 . The projecting rail  52  of one beam section  44  is received in the adjacent receiving slot  54  of the other chord member. Bolts  48  pass through the holes and mechanically secure one beam section to the other beam section to form the transverse beam structure  6 . The length of the transverse beam  6  may be varied by releasing of the mechanical fasteners  48  and moving the sections one to the other until the desired length is achieved. In this way, the transverse beams  6  can be adjusted in length to accommodate different bay widths. This composite structure also allows for salvaging of components if certain portions of the transverse beam are damaged. 
   As can be seen, the top and bottom chords are of the identical section and merely reversed in orientation. If damage occurs to either the top chord or the bottom chord, a new chord member can be inserted. It can further be appreciated that damage may have occur to only part of the chord and a portion of the chord may be salvaged for another application. 
   FIG.  11  and  FIG. 12  shows details of the bracket  100  used to secure the transverse beams  6  to the main beams  4 . The bracket  100  is mechanically secured to the web  3  of the main beam by a nut and bolt connection which passes through the web and passes through holes in the bracket. The transverse beams are mechanically secured to the brackets using the series of holes in the top chord and appropriate holes provided in the bracket  100 . A further brace can extend from the bracket to the bottom chord to increase the stability. Furthermore, the bottom chord members of the parallel spaced transverse beams  6  can be tied one to the other using the bolt slot provided in the bottom chord member to provide bracing. This increases the stiffness and stability of the system. 
   As shown in  FIG. 12 , the transverse beams  6  are secured to the main beams  4  at a position below the top of the main beams  4 . The transverse beams  6  are designed to support the extruded aluminum runner beams  8  which have an overall height of approximately six and one half inches. The upper surface of each runner beam  8  is three and one half inches above the top of the main beams  4 . In this way, a series of wooden four-by-fours  110  can be positioned on the main beams  4  and across the main beams  4  to surround the column  12  and provide a support surface for the plywood deck  14  adjacent the column. In this way, the packing around the columns for supporting the concrete floor adjacent the column is relatively simple and straightforward. This aspect is clearly shown in FIG.  14 . 
   The transverse beams  6  are of a design such that the beam sections cooperate with one another along the top and bottom chords to oppose racking of the sections when the beams are loaded. The beam sections are mechanically secured one to the other and allow for ready adjustment in length of the transverse beams. As can be appreciated, for a given building structure, the bay width is essentially constant and therefore, the truss can be used for forming of the bay floor and then repositioned for forming of the floor thereabove. In many cases, the bay sizes will be somewhat standardized and there will be no requirement to vary the length of the transverse beams. In some cases due to the particular building design, the bay width may be somewhat unusual and thus, the transverse beams can be adjusted in length, to allow formation of the truss of appropriate width. 
   Details of the column hung jack assemblies are shown in  FIG. 15. A  U-shaped saddle member  120  includes a column engaging plate  122  having two outwardly extending arms  124  and  126 . The column engaging plate  122  is mechanically secured to the column using any of the series of holes  128 . These holes allow for aligned or offset bolts. The adjustable jack  130  is received between the arms  124  and  126  and has an overlapping top slide plate  132 . The jack has a securing flange  134  which cooperates with releasable pins  136  to locate the jack at one of three positions shown in FIG.  15 . Each position is shown by one of the pair of vertically aligned locking pin ports  138 . The jack assembly includes a screw member  140  which can be adjusted by means of the bolt adjustment  142  for raising and lowering of the support plate  144 . The support plate  144  engages the lower flange of one of the main beams  4 . To allow movement of the truss out of the bay, the jack is adjusted to drop the main beams onto the support rollers  146  and thereafter, the truss may be moved out of the bay and raised to the next level. The column hung jack assembly of  FIG. 15  allows for minor variation in the spacing of the columns and allows for effective transfer of the loads through the jack to the columns  12 . 
   It is preferred that the composite structural beams  44  and  46  be made of an extruded aluminum alloy components or similar lightweight high strength component. The top chord and the bottom chord are of the identical structure and the diagonal connecting members and the vertical members are tube members with relatively thick sidewalls which have the holes for connecting of the member to the chords and thinner end walls. 
   The transverse beams  6  can be spaced along the main beams  4  anywhere from 64 inches to 108 inches apart. The actual separation of the transverse beams  6  will be determined by the thickness and weight of the slab being poured. 
   The flying form truss, due to the large size thereof, is assembled onsite and is dismantled once the building is complete. The individual components are transported to and from the site and between jobs are stored in a construction yard. The transverse composite beams can be stacked sideways, one on top of the other, and interfit to maintain the stack. This stacking is particularly convenient with the individual beam sections. The projecting, elongate rail  52  is received in a U-shaped receiving channel of an adjacent beam section. This stabilizes the stack and is helpful in transportation and storage. 
   Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by those skilled in the art, that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.