CA1062684A - Portal frame for trench box stack - Google Patents

Abstract

Abstract of the Disclosure A portal frame attached to the open end of a trench box structure and assembling and rigidifying the stacked plural boxes forming the smooth wall sides of the consequent trench box whereby side sections or panels of trench boxes are stackably adjustable as to depth of trench served and the portal span provides maximum clearance for the pipe and inclu-ding thrust plates in the portal frame for transmitting thrust from the boxes and into the portal frame.

Description

The present invention is directed to a new and improved trench box portal frame. The frame i5 secured to plural sides or sections of trench box in stacked edge-wise relation so as to provide adequate rigidity in the enlarged trench box and so as to provide an adjustment of the box in respect to height. This greatly extends the utility of trench box sides and allows the portal frame to be easily knocked down and transported in manageable pieces. In addition, the present struct~re maximizes work clearance for pipe being wor~ed on by the box.
This is a division of copending Canadian Patent Application Serial No. 285,632, filed August 29, 1977.
The principal object of the present invention is to achieve rigidification in plural stacked side sections so that the height of the box can be adjusted to the desired workinq depth and so that a maximum of working clearance ;
is provided at or adjacent to the pipe or work which the trench box straddles.
Still another object is to provide a knock-down transportable construction so that monster boxes can be shipped flat as components instead of requiring the transport of large and unwieldy construction.
Another object is to provide strength in the portal-frame boxes which is enhanced under use conditions.

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According to one aspect of the present invention there is provided a portal frame for securing trench boxes in plural stacked relation, the frame including a pair of vertical structural column elements in spaced-apart relation, each having a pair of spaced-apart flanges with plural pierced openings and a connecting web. A plurality of thrust pads each having an opening therethrough and secured fixedly - -to the web and to the flanges at selected intervals over the sb/~
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length of the columns in register with selected of the pierced openings in the flanges. A truss-like structural arch is connected between the innermost of the flanges of the columns and have fastener openings therethrough in registry with the pierced openings in the flanges.
Fastener means extends through the openings and the thrust pads and sandwiching plural panels of the trenc.h boxes between the flanges in stacked aligned relation.

, According to another aspect of the invention~
;~ 10 there is provided a pair of spaced-apart H-section structural columns with the truss-like structural arch being connected to the innermost of the flanges of the H-, . .
columns and spanning the columns. The plurality of thrust plates are provided on the flanges of the columns at selected of the connections, the truss-like arch to the inner flanges of the H-columns and the plates secured to the H-columns :`1 J at the web and adjacent inner flange thereof. Fasteners are provided through the flanges at the connections and passing through the selected connections and the thrust 2Q plates and through the trench boxes so that the trench ~,, boxes are secured between the flanges of the H-columns and the trench boxes are stress buttressed against the H-columns ;: ~
through the thrust plates.

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- la -sb/~ -` 106Z684 The Prior Art ~. .
Trench boxes are relatively well known and some of the first of such structures were used in wood constructions where a frame construction was built in the trench and shored with vertical lagging in prevention of cave-ins.and the intru-sion of debris. Metal boxes followed, as exemplifiea in the United States Letters Patents to J. M. Rosa et al 2,777,294;
to A. R. S. Morrice 3,641,773; to E. Torti 3,089,310, 3,543,522, 3,473,336: to H. Jost et al 3,541,799; and to J. Krings 3,869,867. Such devices used spreaders to separate the side support plates and included, in some instances, smooth sides, reinforcement, and a variety of fastening means. None propose or suggest the combining of plural sides for stacking and reinforcing portal structure acting to rigidify and strengthen the trench box construction while maximizing the working space.
s, In the DraWings 1 ;
Figure 1 is a perspective view of a portal framed trench box in accord with the present invention and viewed from the ~ . .!
o~en or portal end.
Figure 2 is a front elevation view from the portal end of the trench box seen in the Figure 1.
Figure 3 is a rear elevation view from the end of the trench box of Figure 1 opposite the portal frame end.
Figure 4 is a side elevation view of the trench box of Figures 1-3 and revealing the portal frame in structural ~`1 support of stacked trench box sides at selected height.
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Figure 5 is a top plan view of the structure seen in Figure 4 and showing pipe extending rearwardly of the portal and indicating the accommodation of large diameter pipe or working face.
Figure 6 is a cross-section taken on line 6-6 of Figure

2 and indicating the isolation and journalling procedures for .~ . .
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fasteners extending through the box structure in prevention .of water intrusion between the inner and outer skins of trench ~
box sides. -Figure 7 is a somewhat schematic perspective view of the portal frame and trench box of the present invention in illus-tration of the knock-down aspects of the invention for ease of assembly, handling, disassembly and transport.
j General Description In general, the portal frame comprises a pair of spaced- -apart upright structural section elements such as a pair of H-beams. The wide flanges of the structural section provide gripping means for the ends of plural stacked trench box sides I and at the top the flanges provide simultaneous attachment to ;~ a portal arch-cap which spans the gap between the upright H-beams and attaches to the uppermost of the trench box panels to provide structural stability thereto and all vertical stress components are carried into the high strength vertical H-beams and thence into the stacked plural boxes and through the shoeæ
or skids into the earth of the trench. The portal cap is a truss-like arch and comprises a central web in the form of a rectilinear arch and is stiffened by wide peripheral flanges and-intermediate flange braces in the manner of a truss designed ~;
to carry vertical and torsional loading while assembling the trench box sides and maintaining the proper orientation of the ;
;1,~ upright H-beams în respect to the stacked trench boxes. The vertical ends of the arch extend to interconnect the panel sec-tions and are of a width substantially equal to the inner width flange of the columns or uprights. Lateral diagonal bracing is provided without intrusion on the open work space formed by the portal and extends to connect to the uppermost ,~ of the trench box panels in each side.
At the end of the trench box opposite the portal frame , : :

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is a tubular cross bracing and spacing gage. The tubular cross bracing is socket connected to the trench box sides or walls and the ~ate span is bolted in place beneath the cross bracing. The height of the trench box is established by the number and height size of trench box sides used and this allows ~
;~ the contractor to utilize the trench box sizes for other uses ;
than with the portal frame.
In assembly the selected trench box number of panels to form the sides are fastened at their portal ends to the portal frame and the cross bracing and cross gating is secured at the ; opposite end. The tubular cross bracing is pinned at sockets for easy assembly and disassembly and provides excellent spacing retention for final bolting of the stacked box sides , to the portal frame and cross gating. Those bolts which pass ; through the box sides enter tubular sleeved passageways so as i to prevent the intrusion of water into the box sections. ~his keeps weight and corrosion at a minimum. These same connections, using dismountable fasteners such as bolts, nuts and thrust washers, allow adjustment to manufacturing tolerances at j 2~ assembly. The boxes are metal having substantially smooth inner and outer skins welded to an integral structural frame CQre with upper, lower and intermediate box sections and verti-cal stretchers. The flat knock-down characteristics wil~ be `
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; readily appreciated as the description proceeds and the boxes '1 ,,~, :, and frames are provided in aluminum and steel and the chisel edged skids or running shoes are primarily preferred in steel ;~ having good abrasion resistance. ;~ -~
Specific Description Referring with specific reference to the drawings and ~` ;
~ ~3~ with first reference to the Figure 1 thereof, a portal frame ::3 11 iS illustrated ~hich retains plural trench box sides or panels 12, 13 and 14 in stacked vertical relation and forming -~

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~ 1062684 the spaced-apart composite walls 15 and 16 of a super trench box 17 of selected composite height. When not thus assembled, the trench box sides 12, 13 and 14 may be used by contractors in smaller trench box structures without the portal frame 11.
As can be seen, the portal frame 11 comprises a pair of spaced- - -apart upright or vertical structural columns in the form of ;H-beams 18 held in parallel relation by the portal cap or arch piece 19. As will be seen, the arch or portal cap 19 is con-nected through the box sides and through the wide inner flanges 20 and 20' of the uprights 18. The perimeter flange 21 of the cap 19 is a~out equal in width to the ~langes 20 and 20' of the uprights 18 and may be preassembled and attached to the uprights on the outboard end thereby facilitating attachment . ., to al~gned box and assembled sides 12, 13 and 14 or other ;, selected height combinations. The shoe or skid edges 22 of ~ I . .
the box panels 12 and 14, for example, may face upwardly or downwardly in reference to the ground served and where the I shoe 22 is included on the panel 14 it is preferably faced ~l~ upwardly as shown. ~t ;~ 20 Thus, two lines of bolts on the portal frame 11 are established and distributed as required to provide the adequate bracing and strength in resistance to crushing and torsional ; . .
loading. The outer line of bolts 23 passes through the inner flanges 20' of the H-beam sections and secures the cap 19 to the vertical support elements 18 at the flange interphases.
~i The inner line of bolts 24 pass through the flanges 20 and 20' `i~i and through the inner and outer skins 15 and 16 of the trench ~ box sides 12, 13 and 14. As will be seen, this inner line of .,,.. ~ .
bolts 24, in passing through the sides 15 and 16 at the ends thereof are protected so that Water and debris cannot intrude the structure and increase the weight and corrosion of the trench box 17.

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In Figure 2 the trench box 17 with portal frame 11 is ~ -shown resting in a trench 25 dug into the earth 26 as shown.
The trench box 17 is seen to accommodate a large diameter pipe 27 (phantom line) so that the trench box 17 can be skidded along straddling the pipe 27 and providing ample clearance ~ for work on the pipe within the box and without endangering `~ the pipe 27 or workers. Tubular cross bracing 28 and 29 is visible as installed at the end of the trench box 17 opposite the portal end. As will be seen, these are pinned to cylin-drical stubs projecting inwardly from the skins 15 of the box panels 12, 13 and 14. The cross bracing 29 includes diagonal struts 30 providing torsional bracing. The cross gate 31, sometimes designated as a dirt plate and acting as a spreader, . provides lower separator support between the sides of the trench box 17 and is secured thereto by suitable angles 32 and bolts 33.
In Figure 3 the tubular cross bracing 28 and 29 and the -cross gating 31 and tubular top bar 34 are visible. The pins 35 are seen which provide simple removable connection of the tubular members 28, 29 and 34 to the plural stacked sides or !~ panels 12 and 14 which establish the height of the trench box ~
'~ 17. A pair of splice plates 36 connect the ends of the two ~;
i adjacent stacked sides 14 and 12 by bolting thereto and in facilitation of assembly and erection.
In Figure 4 the portal frame 11 is seen in profile at one end of the multi-tiered trench box 17 made up of trench box sides or panels 12 and 14. In hidden edge lines the skeletal inner structure of the sides 12 and 14 are revealed and comprise a box section top rail 37 or equivalent and box section bottom rail 38 or equivalent with intermediate box sections or stringers 39 in intervals depending for internal ` strength on the height size of the particular side 12 or 14 mjp~

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-` 106Z684 and with vertical structural members 40 as channels or box - sections intermediate the top and bottom rails at spaced intervals as shown. The panels 12, 13 and 14 and their skele-; tal inner support structure are welded together so that the strength of the panels is a composite of the elements (skin and skeletal support) in each panel. The depending skid or ~-raîl shoe 22 is shown extending beneath the side 12. A
structural box section or post 41 is provided vertically at each end of the sides 12 and 14. The stubs 42 are visible in hidden edge line and reinforced by the plates 43 and form the connecting ends for the tubular cross bracing 28, 29 and 34.
As previously related, the structural core is encapsulated on both sides by the attachment of skins 15 and 16 of sheet ; material welded in place. The Figure 5 best illustrates the ability of the trench box 17, made possible by the portal frame 11, to straddle the large diameter pipe 27 (shown here as bell and spigot) by virtue of the high arch and excellent ~ox stabilizing support made possible by the cap structure 19 ;~
secured to the uprights 18 and in turn secured to the arch 2Q ends of the panels or sides 14 and 12 in stacked relation.
The inner and outer bolt lines 23 and 24 are best understoo~
I from this diagram and the spacing and bolt pattern is a matter of selection to provide maximum strength and stability together with ease of fabrication and preassembly of the portal frame 11.
Reinforcing corner braces 50 are shown diagonally and detachably fastened to the arched portal frame 11 and the uppe~ box panels 14 on the inside thereof as shown. Thrust distributing plates 51 at interphase between the panels 14 are employed and the reinforcing structural element 50 is shown as , . d 30 an H or I structural section. A similar thrust plate 52 is applied to the arch structure of cap 19. As constructed, the braces 5Q do not interfere with the arch dimension of the cap . , .

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19 in accommodation of large diameter pipe 27. From the Figure 5 the operation and usage of the trench box 17 can be best appreciated. A trench of adequate depth is dug and the box 17 is dropped into or erected and dragged into position in the trench and provides a shoring or barrier against collapse of the trench walls and the intrusion of mud slides and debris. Pipe is dropped into the space sheltered by the box and is attached to the next preceding section of pipe 27'.
Then the box 17 is advanced toward the left of the Figure 5 into newly opened trench and the shelter of the box 17 is then available for additional sections. The pipe 27 passes out from under the arch 19 as shown. In general, as the diameter of the pipe 27 increases, the length of the pipe sections is relatively reduced so that, depending on the length of box 17 I and pipe sections, several connections can be made. The high arch made possible by the present structure and the adjustment of height by using composite panels 12, 13 and 14 to suit the .1 .
. deFth of trench is a substantial advance in trenching endeavours.

;~ The Figure 6 best illustrates the type of journalling and ~0 isolation used in fastening the sides or panels 12, 13 and 14 to the vertical or upright portal frame members 18. A tube , ' or sleeve 53 is passed through the end box section 41 of the ~anel 14, as shown, and the tube 53 is fillet welded as illus-trated to the skins lS and 16. Mating openings 54 are provided in selected spaced relation along the connecting flanges 55 and these are backed on the inner side by thrust pads 56 and 57, as shown, and the pads 56 and 57 are welded in registering position as the openings 54 thè thicker thrust pad 57 extends ` to contact the web portion of the columns 18 and is welded to the web portion of the columns 18. By use of U-shaped shims ~ 58, final alignment and snugness is established when the bolt ;ij 59 on the inner bolt line is passed through the adjacent ,, mjp/

`; ~06Z684 perimeter flange 21 of the arch-cap 19 and the entire struc-ture is tightened by bolting using nuts and thrust washers in accord with good practice. As will be seen, preliminarily -in the assembly of trench box 17, the shorter bolts 60 with associated nuts and washers are used to secure the arch-cap 19 to the uprights 18. Plural of the tubular sleeve connections in the tubes 53 are provided in accord with trans-lation of stress and in situations in which the connection passes through the box panels 12, 13 and 14 thus eliminating any leaking into the interior of the panels 12, 13 and 14 and in providing assembly tolerance with good bearing strength.
The welding of thrust pad 57 to the web portion of the columns , 18 txansmits vertical and transverse stress from the sandwiched 1~ panels 12 and 14 into the web portion of the columns 18 as is clearly appreciated from the Figure 6.
Assembly and disassembly of boxes 17 can best be under-1, stood by reference to the exploded Figure 7. The portal frame 11 is formed by joining the arch or cap element 19 to the , upright H-beams 18 usîng the outside bolts 60 which pass through the inner facing flanges of the upright members 18 and through th~ ad~acent flanges of the cap 19 where the flanges 21 inter-se ag~inst the uprights 18. The plural panel sections such . as 12 and 14 are placed in stacked relation as shown and are assembled in spaced aligned relation by the attachment of the ~ spreaders 28, 29 and 34 pinned on the stubs 42 and cross ;~3~ braced by the struts 30. Not seen in Figure 7 the splice plates ;~
or straps 36 are secured across the adjacent panel 12 and 14 and the cross gate 31 is bolted between the flanges of the mounting angles 32. This orients one end of the trench box `! 30 17 and pXe~ares the assembla~e for attachment at the portal ~ end to the portal frame 11. This is easily achieved since ;' the verticals 18, with openings for the long bolts 59, receive . :j , - ' '~
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the panels 12 and 14 between the flanges and the long bolts 59 are passed through the flanges and panels 14 and 12 and , the perimeter flange 23 of the arch or cap 19 and at the lowermost bolts 59 beneath the cap 19 the bolts 59 sandwich the panel 12 between the flanges as previously described.
The diagonal bracing 50 achieves a further stabilization against torsional loading.
As will be appreciated, the assembly procedures can be reversed and the consequent disassembly frees the panels 12, 13 and 14 (or whatever height combination sought) for separate use in trench boxes without the portal frame and for use in ''~
shallower and narrower trenches, for example. The inter-mediate panels are preferred to have flush rails top and bottom ', but the top and bottom panels should or may include the shoe or sliding rail 22. As shown in Figures 1 and 2 inversion of the '' upper panel orients the rail 22 upwardly so that the line between panels 12 and 14 is a flush line.
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he potential stacking intervals for height are estab-;, lished by the material limits and the limits of the ground in , 20 ~,hi,ch the trench is formed. Bolt spacing intervals and size of fasteners are a matter of-selection depending upon materials nd particular size and weight of members.
In operation, the trench boxes 17 in cooperation with the portal rame 11 can be shipped in a knock-down condition and the panel sections find use in trench box structures other th~n those described herein. Those skilled in the art will, ap~reciate that variances in width of box is adjusted by chang-~; ing to a shorter cap 19 equating the span with adjustment of -, ,;,, the spacer elements 28,~29, 34 and 31. Where these structures ,,,! ha,ve been used the~ ~aVe been acclaimed as substantially extend-ing the range of use and in facilitating disassembly and storage ',' between jobs. ,, .. .. . ..

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Having thus described my invention and in particular the ~ principal modifications thereof, those skilled in the art will ~ ~ .
perceive other modifications, improvements, and changes and ~
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such modifications, improvements and changes are intended to be included herein limited only by the scope of my hereinafter appended claims.

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Claims

I Claim:

A portal frame for securing trench boxes in plural stacked relation comprising:
a pair of vertical structural column elements in spaced-apart relation each having a pair of spaced-apart flanges with plural pierced openings and a connecting web;
a plurality of thrust pads each having an opening therethrough and secured fixedly to said web and to said flanges at selected intervals over the length of said columns in register with selected of said pierced openings in said flanges;
a truss-like structural arch connected between the innermost of the flanges of said columns and having fastener openings therethrough in registry with said pierced openings in said flanges; and fastener means through said openings and said thrust pads and sandwiching plural panels of said trench boxes between said flanges in stacked aligned relation.

A portal frame for securing trench boxes in plural stacked relation comprising:
a pair of spaced-apart H-section structural columns;
a truss-like structural arch connected to the innermost of the flanges of said H-columns and spanning said columns;
a plurality of thrust plates on the flanges of said columns and at selected of the connections, said truss-like arch to said inner flanges of said H-columns and said plates secured to said H-columns at the web and adjacent inner flange thereof;
fasteners through said flanges at said connections and passing through said selected connections and thrust plates and through said trench boxes whereby said trench boxes are secured between said flanges of said H-columns and said trench boxes are stress buttressed against the H-columns through said thrust plates.