Note: Descriptions are shown in the official language in which they were submitted.
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This invention camprises a concrete tank of
improved s~ructure which i6 easy to assemble on-site from
precast concrete units. More specifically, this invention
relates to prestressed concrete tanks wherein the concrete
core wall is comprised of elongated precast concrete panels
having an outer facing of steel sheet. Even more specîficall~,
this invention relates to a novel and economical method for
connecting adjacent precast concrete panels to form an
integrated assembly having reliable, water tight joints.
Concrete tanks have heretofore been erected from
the ground up at the work site., This method of operation is
inefficient beca~se work is subjected to de~ays due to weather
unavailabilityof materials or labor, ~tc. Efforts have there-
fore been made to bring to the work site, precast concrete
units which can be fabricated at convenient times and places
and typically indoors.
The precast panels typically include a sheet metal
sheathing which is permanently bonded to one face of a precast
concrete panel. The sheathing presents a plurality o~
parallel, longitudinal channels which form a site upon which
mortar may be projected to form an outer coating or wall on
the erected panels. Typically, these precast units are formed
of hydraulic concrete deposited upon a sheet steel diaphragm
in which the parallel, longitudinal channels have alread~y been
formed, the panels being of a length in accordance with the
height of the contemplated tank.
~ hile the advent of precast concrete panels has
simplified the on-site erection of prestressed concrete tanks,
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problems have been encountered in connecting and sealing
the precast units to one another. U.S. Patent No. 3,280,525>
to Crowley suggests a technique for connecting and sealing
precast panels to one another wherein a half channel is
formed on both edges of each precast panel so that adjacent
panels present one full channel which can be locked in place
by the insertion of metal key plate having a cross section
similar to that of the channels but just slightly smaller in
size so as to fit snuggly when driven in place.
The primary object of this invention is to provide
a simpler, more economical and more reliable method and pre-
cast panel configuration so that precast concrete panels
having channels may be more efficiently connected to one
another in the erection of a precast concrete tank.
, It is also an object of this invention to avoid
the expense of providing and handling separate cover plates
as are used in U.S. P~tent No. 3,280,525.
It is also a very important object of this invention
to reduce the number of seals in the joinery between the
adjacent concrete panels so that the chance of leakage from
within the tank is reduced and the amount o sealant and the
work necessary to apply that sealant is also reduced.
These and other objects of this invention are
achieved in a prestressed concrete tank having a core wall
comprising elongated panels of precast concrete having on
their outer faces, a sheet of sheet metal presenting parallel,
longitudinal, undercut channels. The panels also include two
lateral, sheet metal flanges which extend parallel with the
elongated sides of the panels and laterally outwardly
therefrom. The panels are assembled in spaced, side-by-side
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relationship such that the sheet metal flanges on adjacent
panels overlap one another. The overlapping flanges are then
fastened to one another, preferably with sheet metal screws
and an elastomeric compound is used to seal the join~. The
advantages of the instant invention are ~ha~ the steel skin
over the filler joints is part of the steel skin on the panels
and a separate cover plate is not required. Moreover, when the
concrete panels are erectedJ the joint cover is automatically
in place except for sealing and this eliminates the problem of
handling a separate cover plate. Also,there is only one joint
line to seal with elastomeric compound versus two joint lines
in the tank configuration of U.S. Patent No. 3,28Q,525 and thus
the amo~nt of elastomeric material and labor that is required
is reduced by about one half. The invention reduces the chance
o~f leakage from the tank considerably.
The foregoing invention is highly satisfactory in
eliminating expensive cover plates, reducing the joinery and
reducing the likelihood of leakage. ~owever, it has now been
found that by providing the sheet metal diaphragm with seamed
joints set within the precast concrete, the resulting pre-
stressed tank is even more reliable and satisfactory.
It is a further object of the present invention to
provide an improved precast concrete panel which further
reduces the likelihood of leakage from the tank.
It is a further object of the present invention t~
provide an improved means of securing the steel metal sheet
to the precast concrete of the panel.
It is also an object of the present invention to
provide an improved means for preventing the sheet metal
diaphragim from peeling away from the precast concrete a~ the
edge of each panel.
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These and other objects of this invention are
achieved in a panel, having on its outer surface a plurality
of elongated sheets of sheet metal. At least one of the
sheets of sheet metal has parallel longitudinal undercut
channels and each sheet has at least one lip which extends
from the interior side of the sheet metal sheet into the
precast concrete. The lips of adjacent sheets are fastened
together to form a joint in ~he precast concrete. The
advantages of such a construction are that, in addition to
the securing effect achieved by the undercut channels in the
sheet metal, the joint is firmly anchored in the precast
concrete thus securing the sheet metal to the precast concrete.
At the edge of the panel, the joint anchored in the precast
concrete prevents the sheet metal rom peeling away from the
precast concrete. This minimizes the tendency of the sheet
metal diaphragm to peel away from the edge of the panel and
thereby improves the joint between adjacent panels and
minimizes leaks in the tanks at positions where adjacent
panels are connected. At positions interior to the edge ~f
the panels, the joint locks the sheets together and fixedly
secures them to the precast concrete.
Furthermore, it has now been found that the
above-mentioned seaming technique is not only useful in
seaming metal sheets together in the formation of precast
concrete panels but is also useful in seaming adjacent
panels together thus producing a prestressed tank which is
even more reliable and economical.
It is an object of the invention to eliminate the
use of sealant in ioining the adjacent precast concrete
panels together.
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It is also an object of the invention to allow
formation of panels and tanks using a single seaming device
thus reducing costs and complexity.
It is also an important object of this invention
to create a tighter, more waterproof seam between adjacent
panels thus reducing the chance of leakage from within the
tank.
Likewise, it is an object of the invention to
provide a reliable seam between adjacent panels which does
not require the penetration of the sheet metal with sheet
metal screws.
These and other objects of the invention are
achieved in a prestressed concrete tank having a core wall
comprising elongated panels of precast concrete having on
their outer faces a sheet of sheet metal presenting parallel t
.
longitudinal, undercut channels. The panels include lateral
sheet metal flanges which extend parallel to the elongated
sides o the panels and laterally outward therefro~. The
flanges have a ~lange lip on the outermost edge o~ the flange.
The lip extends outwardly from the tank in a direction
substantially perpendicular to the panel. The panels are
assembled in spaced, side-by-side relationship such that
the flange lips of adjacent panels are spaced from one
another. A sheet metal splice member having a channel shape
is interposed in the space between the flange lips oX ~he
adiacent panels. The splice member has upstanding sides
which abut the lips of the adjacent panels. The upstanding
side and the flange lip adjacent to it are seamed together
in a tight fold, thus locking the adjacent panels together.
The advantage of this technique is that it creates
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tighter, more wate~proof seam between adjacent panels without
penetr~ting the sheet metal diaphragm with sheet metal screws or
other fasteners. Furthermore, such a joint eliminates the use
of sealants in joining adjacent paneIs.
More particularly, there i5 provided:
An improved prestressed concrete tank having a core
wall comprising elongated panels of precast concrete assembled
in spaced, side-by-side relationship, each of said panels having
on a face a sheet of sheet metal presenting parallel longitud-
inal undercut channels and a lateral, sheet metal flange extend-
ing parallel with the elongated sides of said panels and later-
ally outwardly therefrom, said sheet metal flange having a lip
on the outermost edge of said flange which extends from the tank
in a direction substantially perpendicular to the panel, said
flange lips of adjacent panels being spaced from one another; a
sheet metal, channel shaped splice member interposed in said
space between the flange lips of adjacent panels, said splice
member having upstanding sides which abut the flange lips of
adjacent panels and said flange lip and abutting upstanding side
being seamed together in a tight fold, thereby locking adjacent
precast concrete panels together with a watertight seam.
There is also provided:
An improved prestressed concrete tank having a core
wall comprising elongated panels of precast concrete assembled
in spaced, side-by-side relationship, each of said panels having
on a face a sheet of sheet metal presenting parallel longitudinal
undercut channels and a lateral sheet metal flange extending
parallel with the elongated sides of said panels and laterally
outwardly therefrom, said sheet metal flange having a lip on the
outermost edge of said flange which extends from the tank in a
direction substantially perpendicular to the panel, said flange
lips of adjacent paneIs being aligned adjacent to and abutting
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each other and said flange lips being seamed together in a tight
fold thereby locking adjacent precast panels together in a water-
tight seam.
There is also provided~
A method for forming prestressed concrete tanks com-
prising the steps of aligning elongated precast concrete panels
side by side, said concrete panels having a sheet metal flang~
which extends parallel with the elongated sides of the panels
and laterally outwardly therefrom said sheet metal flange having
a flange lip extending from said tank in a direction substantial-
ly perpendicular to the panel and being adjacent to and abutting
the flange lip of the adjacent panel; seaming the adjacent
flange lip together in a tight fold; and depositing concrete in
the space formed between the outwardly extending flanges and
precast concrete of adjacent panels.
There is further provided:
An improved prestressed concrete tank having a core
wall comprising elongated panels of precast concrete assembled
in spaced, side-by-side relationship, each of said panels having
on its outer face a sheet of sheet metal presenting parallel
longitudinal undercut channels and a lateral, sheet metal flange
extending parallel with the elongated sides of said panels and
laterally outwardly therefrom, said sheet metal flange having a
lip on the outermost edge of said flange which extends outwardly
from the tank in a direction substantially perpendicular to the
panel, said flange lips of adjacent panels being spaced from one
another; a sheet metal, channel shaped splice member interposed
in said space between the flange lips of adjacent panels, said
splice member having upstanding sides which abut the flange lips
of adjacent panels and said flange lip and abutting upstanding
side being seamed together in a tight fold, thereby locking ad-
jacent precast concrete panels together with a watertight seam.
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There is also provided;
A method of forming paneIs for use in prestressed
concrete tanks comprising the steps of: laying a plurality of
elongated metal sheets of steel in side-by-side relationship,
each of said sheets having an interior and exterior side, at
least one of said sheets having parallel longitudinal undercut
channels and each sheet having a lip extending inwardly at each
elongated edge thereof, the lips on adjacent sheets abutting one
another; laying sheet metal flanges parallel to and adjacent the
two elongated sides of the plurality of elongated metal sheets,
each of said flanges having a lip extending inwardly and abut-
ting a lip on the adjacent sheet of sheet metal; seaming the
abutting lips of said sheets of sheet metal and sheets of sheet
metal and flanges, respectively, in a continuous tight fold; and
depositing concrete on the interior side of said sheet, the said
continuous tight folds extending into the deposited concrete and
serving to anchor the sheet metal sheets and flanges therein.
The invention is more fully described in the accompanying
drawings, in which:
FIG. 1 is a cross sectional plan view of portions of the
concrete tank of this invention showing the assembled panels;
and
FIG. 2 is an elevation view along lines 2-2 of FIG l; and
FIG. 3 is a further cross sectional plan view of a com-
pleted tank according to the invention.
FIG. 4 is a cross sectional plan view of portions of the
concrete tank of this invention showing the assembled panels and
the seamed joints.
FIG. 5 is a cross sectional plan view of a pair of ad-
jacent sheet metal sheets and the lips provided thereon prior to
seaming.
FIG. 6 is a cross sectional plan view of a preferred
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embodiment of a pair of adjacent sheet metal sheets and the lips
provided thereon prior to seaming.
FIG. 7 is a cross sectional plan view of a pair of ad-
jacent sheet metal sheets showing a seamed joint according to
the present invention.
FIG. 8 is a cross sectional plan view of a pair of ad-
jacent sheet metal sheets showing a preferred seamed joint
according to the present invention.
FIG. 9 is a cross sectional plan view of a portion of the
concrete tank showing the splice member interposed
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between the flange lips of the adjacent panels prior to
seaming.
FIG. 10 is a cross sectional plan view o a
portion of the concrete tank showing the improved means
for locking adjacent panels together.
In Figure 1, reference 10 refers generally to a
concrete core wall formed from two precast concrete panels
12 and 14~ Each of panels 12 and 14 has an outer face of
sheet metal 16 which presents a plurality of paralle~l>
longitudinal undercut channels 18. The steel sheet 16 on
each of panels 12 and 14 extends past the edge of the panel
to form a flange 20 on panel 12 and a flange 22 on panel 14.
These flanges extend parallel w,ith the vertical sides of
panels 12 and 14 and extend laterally outwardly therefrom.
Panels 12 and 14 are separated by space 24.
With reference to Figure 2, flanges 20 and 22 on
panels 12 and 14, respectively, overlap one another and are
fastened to one another by means of sheet metal screws 26.
The joint is filled with an elastomeric material 28 and the
entire joint between panels 12 and 14 is filled with filler
concrete 30. The elastomeric materials which are used to
seal the joint may be any of those known for this purpose
including silicone rubbers, polysulfides and the like.
After the core wall is erected as described, an
intermediate wall 32 of cement is ormed on the ~uter steel
facing of the panels. Pneumatically proiected mortar is
used to form an outer coating or wall which tightly seals
in the parallel, lon~itudinal, undercut channels 18 in the
sheet metal facing of the panels. After the intermediate
wall 32 is formed the tank may be prestress~d by wires 34
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and the wires are covered with a further cementitious
covering 36.
Figure 4 is essentially the same as Figure 1
except that the seamed joints 11 have been added at interior
portions of each panel and at the panel edges. Each panel 12
and 14 is made up of more than one metal sheet. The sheets
16a, 16c and 16e contain parallel, longitudinal undercut
channels 18. The edge of panel 12 is provided with sheet 16b
and the edge of panel 14 is provided with sheet 16d, neither
of which have undercut channels. The lateral extensions of
sheet 16b and 16d form flanges 20 and 22, respectively. The
adjacent sides of sheet metal are provided with lips-which
have been seamed together to form a joint 11, which is
anchored in the precast concrete.
The joint may be formed by using the seaming
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machine disclosed and described in U.S. Patent No. 3,120,828.
More specifically, the machine presently being used to form
the seams is the ~OOF RUNNEP~ machine which is available
from the Butler Research Co., Kansas City, Mo. Referring
to,Figures 4 and 5, the metal sheets 16a and 16c are
provided with upstanding lips 15 and 17 which are in abutting
side-by-side relationship. Likewise, in order to form the
joint at the edge of the panel 12, the metal sheets 16a and
16b are provided with upstanding lips 15 and 17 arranged in
abutting side-by-side relationship. Preferably the sheets
to be joined by seaming are laid flat upon a ~or~ surface
with the lips extending upwardly.
The seaming device is placed at one end of the
upstanding lips 15 and 17 and the carriage is moved along
the lips. A series of rolls and counterrolls cause lip 15
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to be folded over or together with and over lip 17 seaming
the two adiacent sheets together into a folded joint 13 as
shown in Figure 7. A second pass of the seaming machine
causes the folded joint 13 tv be ~olded again into the
joint 11 as shown in Figure ~. After the joint ll is formed
the panel is completed by depositing hydraulic concrete upon
the sheet metal. .The concrete covers the joint ll thereby
locking the sheet into the concrete.
Referring to Figure 6, a preferred lip form is
- shown. The preferred lip form includes a male lip 21 and
female lip 19 which are prerolled by conventional methods.
The male lip 21 is formed by turning back the metal. The
female lip 19 is turned over the male lip 21 to form an
inverted V with an angle of approximately 30C. The
advantage of this preferr~d lip form is that a single pass
..
of the seaming machine will result in the formation of the
doubly folded joint shown in Figure 8.
Figures 9 and 10 are essentially the same as
Figure 4 except that the improved method of joining the
precast panels is illustrated.
Referring to Figures ~ and 10, the flanges 20
and 22 are provided with flan~e lips 23 and 29~ respectively,
which extend outwardly from the tank in a direction
substantially perpendicular to the panel. The panels 12 and
14 are erected such that there is a space between them. A
channel shaped splice member 16f is interposed in the space
between the panels 12 and 14. The splice member 16f is sheet
metal and has two upstanding sides 25 and 27. Side 25 abuts
flange lip 23 and side 27 abuts flange 29. Using the
ROOF RUNNERT machine in the same manner described above for
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the formation of joints 11, except that it is used to
vertically seam the adjacent erected panels, tightly
fol~d seams 31 are formed. The entire space hetween
panels 12 and 14 is filled ~ith filler concrete 30.
Another embodiment of the invention comprises
aligning panels 12 and 1~ so that flange lips 23 and 29
are side-by-side and abutting in a manner analogous to
Figures 5 or 6 and forming a single seam to join the
adjacent precast panels.
The majority of the time the placement of the sheet
metal diaphragm is on the outside surface of the struct-lre.
However, there are times, pi-lmarily due to job site condition~;,
exterior connections or inability to brace inwardl~, where the
sheet rnetal diaphragm is placed on the inside surface of ~he
stmcture. lhis is accommcdated by reversing the dircction
of the curvature in the panel beds. All other aspects of the
description re.main identical but, on the interic)r surface except
for the horizontal prestressing which remains on the exterior of
the structure.
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