Roof truss assembly

A wooden truss member including a vertically disposed column section and an upwardly pitched roof beam section angularly disposed from the top of the column section to form a corner therebetween, each section including a hollow frame that is covered by side panels. The two sections are joined at the corner by means of an elongated flange. Plywood panels are used to cover each of the section frames and are arranged so that the grain of each panel runs along the length of the frame section. Special corner panels are mounted between the sections to enclose the corner region therebetween. The grain of the corner panels is arranged to run perpendicular to the corner flanges.

BACKGROUND OF THE INVENTION 
This invention relates to a wooden roof truss and, in particular, to a 
wooden roof truss having a box frame construction in which readily 
available standard size lumber and plywood sheeting is utilized. 
Johnson, in U.S. Pat. No. 3,346,999, discloses a wooden roof truss having a 
box frame construction. The truss is made up of three main sections 
including a vertical column section that is joined to a roof beam section 
by means of an elongated splice section. The splice section is placed at 
the same pitch angle as the roof beam and, in assembly, forms an extension 
of the roof beam. Each of the three sections contain spaced apart chords 
that form the end walls of the section and enclosing sheeting which forms 
the sidewalls of each section. Internal ribs are used to join the chords 
and thus provide additional strength to the structure. The column section 
of the truss contains a knee joint having a cylindrical compression block 
situated at the inside of the joint from which a series of studs radiate. 
Although the joint is relatively strong, most of the stress produced by 
loads are taken up by the elongated splice section, and in particular, by 
the joints between the adjacent column and roof beam sections. If the 
splice is not securely joined to the other two sections, high localized 
stress can build up in this critical region which can lead to failure of 
the truss. 
It should be further noted that the three sections of the Johnson truss are 
co-joined at the time of erection by means of bolts. In this particular 
design, where the splice section is hung between the roof beam and column 
sections, the bolts are forced to carry at least a portion of the truss 
loading. The bolts therefore represent a weak link in the overall 
structure and thus limit the load carrying capacity of the frame. It 
should be further noted that the bolts can be easily bent or otherwise 
deformed if the frame twists or turns as it is being lifted into place at 
the time of erection. 
Underhill, in U.S. Pat. No. 4,483,117, discloses a three part 
pre-fabricated truss that contains a top or peak section and two identical 
side sections which are nailed or bolted together in assembly. The 
sections are fabricated from wooden studs. The entire assembly is thus 
only as strong as the weakest stud section. Although the truss can be 
fabricated easily from standard size pieces of lumber, the overall span of 
the truss is limited as is its load carrying capacity. 
Geffe, in U.S. Pat. No. 4,228,631, and Hunt et al., in U.S. Pat. No. 
3,861,109, both describe composite wooden joists or beams which are 
suitable for supporting flooring or the like. Neither of these patents, 
however, are involved with roof trusses and it would not be possible to 
construct a roof truss using the teachings contained within these two 
patents. 
SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to provide a roof truss 
having a vertical column section and a pitched roof beam section that are 
prefabricated at the factory and then brought together at the time of 
erection to form a composite structure whereby induced loads are not 
permitted to become localized within specific areas of the structure. 
A further object of the present invention is to provide a composite roof 
truss made of wood that can be accurately prefabricated within a factory 
using standard size lumber and sheeting. 
Yet another object of the present invention is to provide a wooden roof 
truss member having a box frame construction that does not require bolts 
or other types of mechanical fasteners to resist induced loads and 
stresses. 
Another object of the present invention is to provide a prefabricated roof 
truss that can be manufactured in two separate sections within a factory 
under close tolerances using adhesive to close the component joints. 
These and other objects of the present invention are attained by means of a 
wooden truss member that includes two factory made sections that are 
joined together at an erection site to create a composite structure 
capable of withstanding high external loads. Each section includes a 
box-like frame that is closed by plywood sheets. An elongated flange is 
located at the corner joint between the sections which provides for 
additional strength in the critical corner region.

DESCRIPTION OF THE INVENTION 
Referring now to the drawings, there is shown in FIGS. 1-3 a partially 
erected building 10 containing a truss assembly embodying the teachings of 
the present invention. The building is specifically designed to store 
particulate material, such as salt or sand of the type generally spread 
over icy road surfaces during the winter months to melt the ice and thus 
reduce driving risks. It should become apparent from the description below 
that the building, however, may be used for other purposes. The building 
includes a series of spaced apart raised concrete pilasters 11--11 that 
are poured into cored holes formed in the ground. In this embodiment of 
the invention the pilasters are erected in a rectangular pattern which 
defines the perimeter of the building. The top surface of the pilasters 
are all raised to the same elevation so that they lie in a common plane. A 
barrier wall 13 is placed inside the pilasters and is raised from ground 
level to the same elevation as the pilasters. The wall is formed of 
pressure treated beams 15--15 that are stacked one upon the other as 
illustrated in FIG. 3. A tongue and groove joint 12 is furnished between 
the abutting beams to strengthen the wall. Galvanized metal inserts 16--16 
having dovetails that are anchored in each of the pilasters and are 
arranged to pass through the joints between adjacent timbers. The terminal 
end of each insert is bent into parallel alignment with the inner face of 
the wall and is nailed to a timber to hold the wall in place and provide 
additional strength. 
The wooden beams forming the barrier wall may be replaced with beams made 
of concrete or any other similar construction that have a high enough 
strength to protect the pilasters from equipment that might be operating 
in the building. In addition, the beams should also be able to withstand 
deterioration when materials such as salt or wet sand is piled 
thereagainst. To this end, the wooden beams are pressure treated to 
prevent the wood from rotting when contacted by salt and/or water. 
A roof truss member designated 20 is seated in an upright position upon 
each of the raised concrete pilasters in the side rows. Each truss member 
includes a vertically disposed column section 21 and an upwardly pitched 
roof beam section 22 which, as will be explained in greater detail below, 
is connected to the top of the column section to form a knee joint like 
corner depicted generally at 19 (FIG. 2). The pilasters are arranged as 
shown in FIGS. 1 and 2 in spaced alignment along the opposing side walls 
of the building. The truss members mounted upon opposing side wall 
pilasters are arranged to come together in abutting contact at their 
crowns with the crowns describing the peak 18 of the roof. As can be 
readily seen in FIG. 1, the present construction eliminates the need for 
horizontal beams, purlin joists, or the like that are typically employed 
in more conventional structures for joining the truss members in assembly. 
The entire area inside the building is thus free from the floor level to 
the roof level of any structural element that might impede the maneuvering 
of heavy or bulky equipment operating inside the building. 
Although not shown, an enlarged doorway is formed in either the front or 
rear wall of the building so that heavy equipment can conveniently enter 
and leave the building. Where the building is used to store road salt or 
sand, a dump truck or the like can enter the building through the enlarged 
door opening, raise the dump body to discharge its load, and without fear 
of encountering any structural members, exit the building with the dump 
body still in an elevated or partially elevated position. Accordingly, the 
need for fixed conveyors and special material handling equipment is 
eliminated. The danger of a truck or the like striking a structural 
building element as it is being maneuvered inside the building is also 
greatly reduced, and the loading and unloading can be carried out rapidly 
and efficiently. 
As illustrated in FIG. 3, the column section of each truss member is 
securely anchored by anchor bolts to the top of a supporting pilaster by 
means of opposing angle plates 24 and 25. The raised arms f the plates are 
connected to the base of the column section by means of through bolts 26. 
A series of J-shaped anchor bolts 28 are cast into the top section of the 
pilaster as shown. The raised portion of each bolt is arranged to pass 
through an enlarged hole (not shown) formed in the base legs of the angle 
plates, and a nut 27 is threaded onto the bolt and tightened against the 
base leg thus securing the truss member in an upright position. 
Each of the two sections making up the truss member contains a hollow 
box-like frame that is assembled as by gluing together standard size 
pieces of lumber. These pieces of lumber can be either 2.times.4 members 
or 2.times.8 members which are cut to any desired length. The side walls 
of the frames are closed in final assembly by means of plywood cover 
panels 65--65. The two sections of the truss are prefabricated under 
closely controlled tolerances at the factory and are shipped to the 
building site for final assembly. All joints between the various wooden 
components are accurately cut and closed at the factory using suitable 
high strength bonding material. As a result, each truss section leaving 
the factory, although made of wood, represents a unitized structure 
capable of withstanding extremely high external loads. 
Turning now to FIG. 4, there is shown a frame assembly 30 of the column 
section 21. As noted, all frame members are cut from standard size pieces 
of lumber having the same cross sectional dimensions. The frame includes a 
vertically disposed outer chord 31 which consists of two studs glued in 
face-to-face contact along their respective lengths. The studs are mounted 
edgewise in the frame with the chord forming the outside wall 32 of the 
column. 
The inside wall of the column is similarly formed by inner chord 33 made up 
of two studs glued in face-to-face relationship. The inner chord which 
forms the inside wall 34 of the column, is spaced apart from the outer 
chord and is set at an angle so that the width of the column increases 
uniformly from the base 35 of the column toward the top of the column. The 
base of the column is a thick wooden plate generally referenced 35 that is 
made up of a series of wooden blocks that are glued together in a stacked 
configuration. The plate is perpendicularly aligned in regard to the 
vertically disposed inner chord. The plate is thick enough so that the 
through bolts 26 holding the column to the anchoring angle irons will pass 
therethrough. A series of horizontally disposed internal ribs 37--37 are 
mounted between the two chords and provide additional strength to the 
column. The rib thickness is increased in any region where the side wall 
cover panels will be joined in abutting contact as for example, at joints 
38--38 (FIG. 6). These multiple ribbed members shall be referred to herein 
as "splices" and are depicted in FIG. 4 by the reference number 39. In 
this case, the splices are formed by gluing three ribs together in 
face-to-face contact. 
The top portion of the column section includes a bottom corner subsection 
40 that extends upwardly from a double splice 41 to the top portion of the 
column. The bottom corner subsection includes an elongated flange 42 that 
forms the upper wall of the column section. The flange is inclined 
downwardly from the outer chord and extends inwardly beyond the inner 
chord of the column. A brace member 43 is secured at one end to the 
extended portion of the flange and at the other end to the inner chord at 
a point adjacent to the previously noted double splice 41. A web 44 is 
connected between the inside corner formed between the brace member and 
the flange and the inner chord of the column section to provide added 
rigidity and stiffness to the bottom corner subsection. In this particular 
construction, the flange member is again fabricated by gluing top studs 
together in a face-to-face configuration. The brace and web members, 
however, are fabricated from single studs because of different load 
bearing considerations. 
FIG. 5 shows the frame 48 of the pitched roof beam section of the truss 
member. Here again, the frame components are accurately cut in the factory 
to close tolerances and are glued together prior to shipment to provide a 
unitized high-strength assembly. The roof beam frame 48 includes an outer 
chord 49 that forms the outside wall 46 of the section and a spaced apart 
inner chord 50 that forms the inside wall 47 of the section. The inner 
chord is inclined so that the width of the roof beam section increases 
uniformly from the upper ends 51 towards its lower end. A vertically 
disposed crown member 52 consisting of two glued together studs is 
situated at the terminal end of the beam, the purpose of which will be 
described in greater detail below. 
The roof beam section of the column also includes a top corner subsection 
54 that encompasses the lower end of the roof beam section. The top corner 
subsection 54 includes an elongated flange 56 that extends inwardly at an 
angle from the upper chord 49 to a point beyond the lower chord. The beam 
flange 56 is coextensive in length with the column flange member 42. The 
two flange members are brought together in final assembly to form an 
elongated corner connection 53 illustrated in FIG. 7. The corner 
subsection of the roof beam further includes a brace member 57 and a web 
58 that are bonded to the roof beam. 
As further illustrated in FIG. 5, the inner and outer chords of the roof 
beam section are extra strength members that are formed by gluing together 
studs in face-to-face contact. Ribs 60--60 are mounted at intervals 
between the chords as well as a plurality of triple thickness splices 
61--61 in those regions where the side wall sheeting 65--65 (FIG. 6) forms 
a joint 38. In addition, longitudinal splices 62 and 63 are provided along 
the inside of the chords behind joints formed along the chords. A double 
splice 65 is also provided which defines the inner boundary of the top 
corner subsection 54. In this section, all ribs are mounted perpendicular 
to the upper chord 49. 
The column and beam sections are partially enclosed at the factory by 
gluing plywood cover panels 65--65 over the two section frames. As noted, 
all joints between panels occur over a splice so that the end portions of 
the panels can be securely glued to the frame. The two corner subsections 
40 and 54, however, remain uncovered until such time as the two sections 
are joined together at the erection site. At the time of final assembly, 
the two elongated flange members 42 and 56 are aligned in abutting contact 
as shown in FIG. 6 and the flanges are then bolted tightly together to 
securely attach the roof beam section to the column section. When the two 
sections are assembled, the brace members 43 and 57 are brought into 
coplanar alignment to form an elongated bracket that helps to support the 
angled roof beam upon the column. 
The elongated connection 53 (FIG. 6) between the column and the roof beam 
occurs along a line of maximum moment and therefore the elongated flange 
members and the brace members and not the bolt carry the entire load in 
this corner region. 
A metal tension plate is connected over the outside of the corner 69 formed 
between the two sections. The plate is secured in place by nailing, 
lagging or wood screwing it to the adjacent outer chords of the column and 
roof sections. Holes 73--73 are provided in the strap in correct 
quantities and sizes to provide adequate shear connectors for the tension 
in this member. The tension in this member is determined by span, height, 
dead load, snow load and wind load and must be calculated to meet existing 
conditions of the location of the building. 
After the column has been joined to the roof section, the two adjacent 
corner subsections are closed by gluing a corner panel 75 over the corner 
on either side of the assembled truss member. The grain of the cover 
panels is arranged so that it runs generally perpendicular to the 
elongated flange members. The remaining cover panels are arranged so that 
the grain of the panels run lengthwise along the sections. By so aligning 
the panels, and securely gluing them to the section frames, the panels 
serve to unitize the entire structure and provide a maximum amount of 
strength to the truss. 
Prior to hoisting a truss member into place upon a support pilaster, the 
truss member is attached at the crown to a companion truss as shown in 
FIG. 9. The opposing crown members are aligned in abutting contact as 
shown using a single bolt 80 that is passed through the adjacent crown 
members and locked in place using nut 81. Access ports 82--82 are provided 
in the adjacent roof beam panels to permit insertion and tightening of the 
bolts. A crown plate 85 is placed over the crown joint formed by the 
abutting roof beam sections and is fastened to the sections using screws, 
nails or the like. The crown plate helps keep the crown joint tightly 
closed, however, because of the construction of the truss member, it is 
not required to resist any external loading. 
Leger strips 86 (FIG. 10) are bonded to the opposing side walls of the roof 
beam section a predetermined distance from the top surface 87 of the roof 
beam section. Similar legers 88--88 (FIG. 2) are also bonded to the 
opposing side walls of each column section. The legers provide additional 
strength to the sections and also furnish seats upon which sheeting is 
attached. 
As illustrated in FIG. 10 the sheeting consists of individual units 90--90 
that include an elongated sheet 91 of plywood, pressed fiber board or the 
like. A series of joists 92 are glued to the back of each sheet that are 
arranged to rest in assembly upon the leger strips carried by adjacent 
truss members. Adjacent sheets 91--91 are further adapted to pass over the 
top of the truss members and form a tight joint 93 that extends along the 
length of the outer chord of the covered section. Again, the joints 
between the sheeting units and the contacted truss surfaces can be closed 
by gluing to provide a tight weather resistant closure. 
While this invention has been explained with reference to the structure 
disclosed herein, it is not confined to the details set forth and this 
application is intended to cover any modifications and changes as may come 
within the scope of the following claims.