Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1 MODULAR SCAFFOLDING SYSTEM
2 TECHNICAL FIELD
3 [0001] The following relates generally to modular scaffolding systems,
and more particularly to
4 scaffolding systems comprising modular truss sections.
BACKGROUND
6 [0002] Scaffolding refers to a temporary structure used to support a work
crew and some building
7 materials during a construction project.
8 [0003] Scaffolding structures generally comprise several vertical posts
(commonly referred to as
9 "standards") spaced apart longitudinally by truss sections, and spaced
apart laterally by other
members (commonly referred to as "bearers"). Each of the truss sections and
bearers are joined
11 to the vertical posts by clamps or other fixing mechanisms. Scaffolding
structures are often topped
12 with a series of beams which may be covered by a deck (often made of
plywood planks) for
13 permitting movement thereupon by members of the work crew or placement
of equipment.
14 [0004] Scaffolding is most commonly assembled from a series of pre-
constructed parts having
desired dimensions for the particular use. Truss sections of scaffolding
systems, particularly when
16 used as part of the span of a structure providing a temporary bridge or
suspended walkway, are
17 commonly sized to be about 14' long, though may also be fabricated to
various other lengths, for
18 example 17', 21' or 28'.
19 [0005] Manipulation of such truss sections is burdensome. The truss
sections are long, heavy,
and hard to work with. Transportation of the sections is also costly.
Moreover, on a construction
21 site, because the longer sections cannot fit into elevators, they often
have to be hoisted upward
22 as a construction project ascends its successive stages.
23 [0006] Modular scaffolding systems are known. Most include geometrically
complex, easily
24 broken attachment pieces for connecting parts in order to achieve
modularity. Often such
attachment pieces comprise brackets for encircling the ends of horizontal
members of, for
26 example, the truss sections.
27 [0007] A simpler, versatile, easy to use modular scaffolding system is
needed.
28 DESCRIPTION OF THE DRAWINGS
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1 [0008] A greater understanding of the embodiments will be had with
reference to the Figures, in
2 which:
3 [0009] Fig. 1 shows an embodiment of the modular scaffolding system
comprising two truss
4 sections;
[0010] Fig. 2 shows a view of a single truss section, a connector and an
optional support;
6 [0011] Fig. 3A shows the connection between an example truss section and
a post;
7 [0012] Fig. 3B shows an embodiment of the optional support;
8 [0013] Fig. 4 shows a method of assembling the modular scaffolding
system;
9 [0014] Fig. 5 shows the modular scaffolding system in use as part of a
scaffold structure;
[0015] Fig. 6 shows possible dimensions of the modular scaffolding system;
11 [0016] Fig. 7 shows an experimental setup for testing the modular
scaffolding system;
12 [0017] Fig. 8 shows the modular scaffolding system under load testing;
13 [0018] Fig. 9 further shows the modular scaffolding system under load
testing; and
14 [0019] Fig. 10 shows different combinations of scaffolding sections.
DETAILED DESCRIPTION
16 [0020] For simplicity and clarity of illustration, where considered
appropriate, reference numerals
17 may be repeated among the Figures to indicate corresponding or analogous
elements. In addition,
18 numerous specific details are set forth in order to provide a thorough
understanding of the
19 embodiments described herein. However, it will be understood by those of
ordinary skill in the art
that the embodiments described herein may be practised without these specific
details. In other
21 instances, well-known methods, procedures and components have not been
described in detail
22 so as not to obscure the embodiments described herein. Also, the
description is not to be
23 considered as limiting the scope of the embodiments described herein.
24 [0021] Various terms used throughout the present description may be read
and understood as
follows, unless the context indicates otherwise: "or" as used throughout is
inclusive, as though
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1 written "and/or"; singular articles and pronouns as used throughout
include their plural forms, and
2 vice versa; similarly, gendered pronouns include their counterpart
pronouns so that pronouns
3 should not be understood as limiting anything described herein to use,
implementation,
4 performance, etc. by a single gender; "exemplary" should be understood as
"illustrative" or
"exemplifying" and not necessarily as "preferred" over other embodiments.
Further definitions for
6 terms may be set out herein; these may apply to prior and subsequent
instances of those terms,
7 as will be understood from a reading of the present description.
8 [0022] As set out above, an improved modular scaffolding system is
needed, particularly to
9 enable easy manipulation of truss sections to various lengths for use in
scaffolding bridges and
suspended walkways.
11 [0023] Various embodiments are described herein relating to scaffolding
systems where truss
12 sections can be assembled together with connectors to achieve length
modularity. To assemble
13 the truss sections, a pair of connectors are positioned within openings
defined in the horizontal
14 runners of each truss section, such that the connectors extend between
successive assembled
sections, and the connectors are each further fixed to the sections with one
or more fasteners.
16 Additionally, each truss section has a vertical member extending between
the horizontal runners
17 proximal the connectors in order to enable acceptable vertical loading
characteristics.
18 [0024] With the scaffolding systems described herein, manipulation,
assembly and disassembly
19 of various lengths of truss sections is facilitated. Erection of
scaffolding systems having different
lengths to fit the needs of different construction jobs is thereby
streamlined. Surprisingly, the
21 systems have been found to have similar strength to resist vertical
loading in some configurations
22 as if the assembled truss sections were integrally formed.
23 [0025] Various embodiments of the modular scaffolding system will now be
described with
24 reference to the drawings.
[0026] Referring to Figs. 1 to 2, shown therein is a modular scaffolding
system 100 comprising a
26 first truss section 102, a second truss section 104, and a pair of
connectors 118. As will be
27 appreciated from the following, additional truss sections can be added
to achieve different desired
28 lengths (referred to as the "span" of the truss sections).
29 [0027] The first truss section 102 comprises at least two vertical
members 116, at least two
horizontal runner members 110 (referred to as "runners") spaced apart by the
vertical members
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1 and one or more diagonal braces 112 (providing the 'truss' construction).
The diagonal braces
2 may be disposed at various angles with respect to the runners, for
example 55 degrees. At a first
3 end 109 of the first truss section, it is attached by a known attachment
mechanism 106 to a vertical
4 post 108 (a "standard"), for example of a scaffolding tower. The
attachment mechanism may
comprise a clamp, though other attachment mechanisms are known to those of
skill in the art. At
6 a second end 111, each horizontal runner is shaped to define an elongate
opening 124 for
7 receiving a portion of an elongate connector pin 118 (best shown in Fig.
2). Throughout the
8 description, the end of a runner proximal a connector is referred to as a
"connection end", shown
9 as element 111 for truss section 102, or 111' for truss section 104.
[0028] The second truss section 104 has fundamentally the same construction as
the first truss
11 section, though the disposition of its defined openings and the
attachment mechanism connecting
12 it to the illustrated vertical post are each shown to be horizontally
flipped compared to the first
13 truss section, and the second truss section is shown to be shorter
longitudinally than the first truss
14 section. It will be appreciated from the following that each truss
section may be connected to a
vertical post at one end and define openings for receiving a connector pin at
the other, or may
16 define openings at both ends (and thus have two connection ends),
depending on the positioning
17 of the truss section in the respective scaffolding system. For example,
a truss section positioned
18 between two other truss sections will define openings for receiving
connectors at each end.
19 [0029] It should be appreciated that the scaffolding system 100 forms
one panel of a scaffold
structure. To form a complete scaffold structure by making use of the
scaffolding system 100, the
21 vertical posts 108 may be joined with additional truss sections,
tangential members ("bearers"),
22 and ultimately indirectly connected to several other vertical posts.
Further, once assembled,
23 beams and a deck may be added atop the scaffold to permit movement of
work men above.
24 Referring to Fig. 3A, shown there is an illustration of an example truss
section 102" with runners
110" and vertical member 116" connected to a post 108" with clamp 106", the
section is shown to
26 have a height of 500mm.
27 [0030] To assemble the first truss section 102 and the second truss
section 104 in order to
28 achieve modularity, a connector 118 is positioned within, and extends
between, the elongated
29 openings 124 of each runner of the truss sections (best shown in Fig.
1). Each connector 118 is
further fastened to the two truss sections in which it is positioned (best
shown in Fig. 2). For
31 connection between successive truss sections to be possible with the
described system, each
32 truss section must thus have elongate openings at each end where it is
desired to be assembled
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1 with another truss section, such openings of successive sections being
opposed during assembly
2 to fully receive the connector.
3 [0031] To enable fastening of the connectors to the truss sections, in a
particular embodiment
4 illustrated in Fig. 2, each connector defines four apertures 120, and a
pair of apertures 122 are
defined proximal the connection end of each runner to coincide with the
apertures of the connector
6 when the truss sections and connector are positioned for assembly. A
suitable fastener 131 can
7 then be passed through the aligned apertures to complete the assembly. A
bolt and a nut has
8 been found to provide a suitable fastener 131. Other types of fasteners
are contemplated.
9 [0032] In other embodiments comprising similar fasteners, more or less
apertures may be
defined. For example, the connector may define two apertures, and a single
aperture may in that
11 instance be defined at the connection end of each runner. However,
assuming each respective
12 fastener is of the same strength, generally having more than one
fastener is advantageous as it
13 distributes shear stress between more than a single fastener, reducing
the risk if a fastener
14 shears, and eliminating the existence of a single point of failure.
[0033] In order to bear any vertical downward force upon the truss sections
(i.e. along the
16 direction of the vertical member, at least one vertical member 116 is
disposed proximal the
17 connection end of each truss section, extending between the runners.
Though the vertical
18 members 116 and 116' are shown to be spaced a short distance from the
connection ends of the
19 runners, it may be optimal for the vertical member to be positioned
substantially adjacent the
connection end of the runners to improve loading characteristics.
21 [0034] In embodiments where two apertures are provided at the connection
end of each runner
22 for receiving fasteners, preferably the apertures are spaced about the
proximal vertical member
23 (see member 116' illustrated in Fig. 2), helping to evenly distribute
forces about the fasteners 131.
24 In embodiments where a single fastener is provided at each connection
end, it may be positioned
to be aligned with the proximal vertical member.
26 [0035] Referring now to the construction of the truss sections, the
members are all preferably
27 made of steel, aluminum or a composite scaffolding material (which may
include glass or nylon
28 fiber). The connector is preferably made of a solid piece of material,
preferably a metal, such as
29 steel or a material having similar strength characteristics for the
relevant type of loading. As is
common in the scaffolding industry, the runner members and vertical members
may have a
31 tubular construction, though other shapes are possible. The elongate
openings may thus
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1 comprise part of the tubular shape rather than a separate defined
geometry. This eliminates the
2 need to adapt the connection end of the runners to form a particular
shape of opening, rather than
3 utilizing the pre-existing tubular shape in common use today. However
other shapes of the
4 elongate openings and connector are contemplated. Particularly, the
elongate opening may have
a square or rectangular profile. In the rectangular case, the vertical
direction may define the length
6 of the rectangular profile. In each case, the connector preferably has a
complementary shape
7 profile to the openings, and the openings must extend long enough into
the runners to receive the
8 connector (by neighbouring truss sections) when assembled.
9 [0036] Optionally, a support 126 may be added to the scaffolding system
if loads are expected to
be high. Once two truss sections are assembled, the support 126 may be
positioned below the
11 truss sections to extend therebetween, and be attached thereto for extra
support (as best shown
12 in Fig. 5). As the truss sections are loaded, they experience some
downward deflection along
13 their span, which may be most pronounced around the bottom connector.
During loading, it has
14 been found the point of failure is thus commonly the bottom connector
(and its fasteners). The
attachment of the support 126 below the bottom connector, can provide some
extra support to
16 minimize deflection and reduce the risk of failure. The support may
comprise a member 130,
17 which may be tubular or rectangular, and fasteners 128, such as bolt
clamps, for attaching the
18 support to the truss sections. Fig. 3B shows an example support 126',
comprising a bolt clamp
19 128' and a member 130' having a rectangular profile for positioning and
attachment below a
bottom truss section of the modular scaffolding system as described above. The
illustrated
21 member has a length of 15".
22 [0037] Referring to Fig. 4, a method 200 is shown for assembling truss
sections of the modular
23 scaffolding system. At block 202, connectors are partially inserted into
the openings 124 of the
24 runners of a first truss section. At block 204, a second truss section
is then positioned such that
its openings oppose the openings of the first truss section, and the second
truss section is
26 manipulated to be adjacent the first truss section, such that the
openings of the second truss
27 section receive the remaining portion of the connectors previously
received by the first truss
28 section, and the connectors thereby extend between the truss sections.
At block 206, each
29 connector is fastened to the truss sections by means of one or more
fasteners. At block 208, to
enhance the load bearing characteristics of the truss sections, a support 126
may be fastened to
31 extend between to the truss sections below the bottom connector. Once
the truss sections are
32 coupled, at block 210, the truss section may be used as a panel of a
scaffold structure, for
33 example by being joined to the vertical posts of the structure.
Optionally, the first truss section
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1 can be connected to the vertical post of the scaffold before assembly
with the second truss
2 section.
3 [0038] Referring to Fig. 5, shown therein is a scaffolding system 301 in
use to provide a scaffold
4 structure. The scaffolding system 301 comprises three truss sections 308,
310, 312, joined
together by connectors, with supports 126. Truss sections 308 and 312 are
respectively joined to
6 the posts of scaffold towers 302, 304. Further, a cross-bracing member
314 (also referred to as
7 "ledger") is shown to be attached between the scaffold towers,
longitudinally stabilizing the towers,
8 and minimizing shear stresses on the fasteners of the connectors.
9 [0039] Possible dimensions of the various elements will now be described
with particular
reference to Fig. 6. In the background, it has been described that truss
sections are commonly
11 made to specific lengths, which may be too large to be easily
manipulated (e.g. 21'). The above
12 described embodiments of the scaffolding system achieve modularity
because truss sections of
13 varying lengths can be attached together to arrive at spans having a
desired length. Particularly,
14 short truss sections - which are easily manipulated - can be combined to
arrive at longer spans
of useful lengths. Fig. 6, at elements 602 and 604 illustrates possible
combinations of truss
16 sections to arrive at commonly used lengths. Element 602 comprises two
truss sections 15246
17 measuring 7 feet (2130mm, as indicated), and a section 15245 measuring 3
feet (920mm), to
18 arrive at a section measuring 17'. Element 604 comprises two sections
15246 and a section
19 15247, each measuring 7', to arrive at a section measuring 21' (6390mm).
Each of the various
members may be tubular and have a diameter of 48.3mm.
21 [0040] Fig. 6 also shows at element 15249 that a possible length of the
connector for spans
22 having the dimensions in Fig. 6 is 15 3/4" (400mm), with a diameter of
40.3 mm.
23 [0041] Referring now to Figs. 7 to 9, exemplary experimental results
conducted by the Applicant
24 will now be described.
[0042] Referring to Fig. 7, shown therein is an illustration of the
experimental configuration of the
26 truss system to achieve the experimental results. Four 7' truss sections
706, 708, 710, 712 were
27 joined by connectors and coupled at the ends thereof to posts of
scaffolding towers 704, 714. The
28 truss sections were the same as parts 15246 and 15247 shown in Fig. 6.
29 [0043] Loads were then successively added, as shown at P1, P2, P3, P4
until failure. The
maximum load applied to the configuration was 35,271.6 lb (156.9 kN)
representing 82.15 lb per
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1 square foot (3.93 kN/m2) loading or 157.46 pounds per linear foot (2.3
kN/m) of truss with a Factor
2 of Safety of 4:1. The towers 704 and 714 were 3'10" (1.17m) square towers
erected at each end
3 of the setup, with the 28 foot modular trusses mounted between the
towers. Each of the towers
4 704, 714 was loaded with ballast to ensure that unwanted deflection would
not occur due to
deformation of the towers. Ledgers and screwjacks were set on the floor
between the towers to
6 correctly position the towers. Ledgers (i.e. cross-brace 702) were
attached to the bottom chords
7 of the trusses to provide lateral bracing to ensure that the trusses
would not twist under load.
8 [0044] Loading was carried out by setting racks of equipment onto a
plywood platform supported
9 by aluminum beams mounted across the trusses. Deflection (A) at the
center of the trusses was
noted as each rack was placed onto the platform. The load was gradually
increased until failure.
11 It is noteworthy that the tested configuration was found to only be
about 10% weaker to vertical
12 uniform distributed load ('UDL") than a comparable construction
including truss sections integrally
13 joined.
14 [0045] Referring to Figs. 8 to 9, Element 802 shows the initial setup.
Element 804 shows
positioning of a first rack at P2 of Fig. 7. Element 806 shows addition of a
second rack at P3.
16 Element 808 shows a deflection measurement by laser. Element 810 shows
addition of a fifth
17 rack at P2. Element 812 shows addition of a sixth rack at P3. Element
812 shows addition of a
18 seventh rack at P1. Element 814 shows addition of an 8th rack at P4.
Element 816 shows addition
19 of a final load, causing collapse.
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1 [0046] Table 1 shows results of a first load test.
2 Table 1
P1 P2 P3 P4 IP A IA Comments
(LB) (LB) (LB) (LB) (LB) (IN) (IN)
0 0 0 0 0 26 3/16 0 No
apparent distress
0 4000 4000 25 3/4 7/16 No
apparent distress
0 4000 4000 8000 25
3/16 15/16 No apparent distress
0 4000 4000 4000 12000 25 1/16 1 1/16 End towers apparently
require more bracing
3
4 [0047] Table 2 shows results of a second test after checking that
standards (i.e. vertical posts)
were vertical, and installing ledgers (i.e. cross-bracing) on three sides,
ensuring that the now four
6 ledgers are leveled in place, and leaving the front open for loading.
7
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1 Table 2
P1 P2 P3 P4 IP A IA Comments
(LB) (LB) (LB) (LB) (LB) (IN) (IN)
0 0 0 0 0 25 3/8 0 No apparent distress
0 4000 0 0 4000 24 7/8 1/2 No apparent distress
0 4000 4000 0 8000 247/16 15/16 No
apparent distress
4000 4000 4000 0 12000 24 1/4 11/8 Not
enough space for 4th
rack ¨ use shorter ledgers
4000 4000 4000 3000 15000 24 1 3/8 No apparent distress
4000 8000 8000 3000 23000 23 2 3/8 No apparent distress
4000 8000 8000 7000 27000 22 1/8 3.25 No apparent distress
7000 8000 8000 7000 30000 21 5/16 4 1/16 No apparent distress
8650 8000 8000 8650 33300 --
Insufficient height to add
another rack. Add pallets
of counterweights - collapse
2
3 [0048] Table 3 shows a review of the loading results with the test
configuration.
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1 Table 3
2 Base Load:
QTY UNITS DESCRIPTION UNIT WEIGHT TOTAL CUMULATIVE
6 Sheets 4x8x3/4 plywood 2.2 psf 422.4 422.4
21 Al. Beams 6 ft 4 plf 504.0 926.4
6 Ledgers - 7 ft 105.6 1032
12 Clamps Swivel Bolt 3.3 39.6 1071.6
3
4 Supported Load:
QTY UNITS DESCRIPTION UNIT WEIGHT TOTAL CUMULATIVE
6 Racks 7 ft Ledgers 4000 24000 24000
2 Racks 5'2 Ledgers 3000 6000 30000
2 Pallets 50 lb Counterweight 1650 3300 33300
8 Each Racks 100 800
34100
2 Each Pallets 50 100 34200
6 Total Load just prior to failure = 34200+1071.6 = 35271.6#
7 Square foot loading = 35271.64(46/12)x281= 328.6
8 Safe Working Load = 328.6/4 = 82.15 psf
9 Per Truss = 41 psf
11 Total Linear Load: 35271.6/28 = 1259.7 pounds per linear foot (2
trusses)
12 Safe Working Load: 1259.7/4 = 314.925/2 ¨ say 157 pounds per linear foot
per truss
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1 [0049] Referring to Fig. 10, shown therein are parts 1001, 1002, 1003,
1004, 1005 comprising
2 different combinations of truss sections. Table 4 shows loading
characteristics for the parts.
3 Table 4
Part Length Allowable Setup No. of Equal
Allowable
Number Uniform Load Loads Spacing
Load (P)
M FT KN/M LB/FT M FT KN LB
1001 4.27 14 4.6 315 1 1 2.13 7
9.8 2200
1002 5.18 17 3.8 259 2 1 2.59 8.5 9.8
2200
1003 6.40 21 3.1 210 3 2 2.13 7 7.3
1650
1004 7.32 24 2.6 180 4 1 3.66 12
9.6 2160
1005 8.53 28 2.3 158 5 3 2.13 7
4.9 1100
4
[0050] Although the foregoing has been described with reference to certain
specific
6 embodiments, various modifications thereto will be apparent to those
skilled in the art without
7 departing from the spirit and scope of the invention as outlined in the
appended claims.
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