U.S. patent application number 11/800611 was filed with the patent office on 2008-11-13 for foundation for modular structures.
Invention is credited to Jeff Brown-Miller, Gerald T. Larson, Bruce H. Middleswart.
Application Number | 20080276555 11/800611 |
Document ID | / |
Family ID | 39968267 |
Filed Date | 2008-11-13 |
United States Patent
Application |
20080276555 |
Kind Code |
A1 |
Larson; Gerald T. ; et
al. |
November 13, 2008 |
Foundation for modular structures
Abstract
An improvement for building perimeter-wall foundations is
created by attaching galvanized-steel corrugated panels to an
in-place structure. The freely hanging bottom edges of the panels,
which have continuous deformation specific to the enhancement of
bearing and anchorage within concrete, are cast in-situ with
footing concrete, so becoming a cast-in-place perimeter-wall
foundation, capable of residential-scale bearing and shear
loadings. A load bearing pier support is included for load bearing
supporting large or multi-unit modular structures.
Inventors: |
Larson; Gerald T.; (Phoenix,
AZ) ; Middleswart; Bruce H.; (Phoenix, AZ) ;
Brown-Miller; Jeff; (Phoenix, AZ) |
Correspondence
Address: |
The Halvorson Law Firm
Suite 130, 1757 E. Baseline Rd.
Gilbert
AZ
85233
US
|
Family ID: |
39968267 |
Appl. No.: |
11/800611 |
Filed: |
May 7, 2007 |
Current U.S.
Class: |
52/293.1 |
Current CPC
Class: |
E02D 27/30 20130101;
E02D 27/02 20130101; E04B 1/34352 20130101 |
Class at
Publication: |
52/293.1 |
International
Class: |
E02D 27/00 20060101
E02D027/00 |
Claims
1. An improved method of constructing a foundation wall for a
modular building, comprising the steps: providing an elongate
physical guide means along a line at a predetermined height above
ground at which the top of said foundation wall is desired to
exist, said foundation wall to extend downward between said
elongate physical guide means and the earth, preparing the surface
of the earth beneath said elongate physical guide means for
foundation support to achieve predetermined foundation design
loads, including lateral loads, shear loads, uplift loads and
bearing loads, forming a plurality of corrugated structural panels,
wherein each panel includes a lower portion having footing
engagement means formed integrally in said panel, and wherein each
panel is formed to be a predetermined height required at its
location between said elongate physical guide means and said
prepared earth, and said footing engagement means is cut or formed
to achieve said foundation design loads, attaching to said elongate
physical guide means in a manner so as to hang between it and said
prepared surface of the earth along three sides of said elongate
physical guide means, said plurality of structural panels, each of
which said structural panels is of a suitable thickness and
strength to support a corresponding part of a building above, each
of which said structural panels so extends toward earth, in a
substantial plane where said foundation wall is desired; providing
at least one internal permanent load supporting piers along
internal load bearing sections of the elongate physical guide
means, wherein each internal permanent load supporting piers
comprises a cap plate with at least one securing apertures, a base
plate having concrete anchors formed onto said base plate and a
central pier that spans between the cap plate and the base plate,
and wherein each internal permanent load supporting pier is at a
predetermined height required at its location between said elongate
physical guide means and said prepared earth, and said base plate
with concrete anchors is cut or formed to achieve said foundation
design loads; thereafter placing a flowable hardenable building
material about the lower portion of each of the attached plurality
of said structural panels and internal permanent load supporting
piers to form a footing therefore along three sides of the elongate
physical guide means, and making each said panel and internal
permanent load supporting piers become supported in the flowable
hardenable building material to achieve said design loads, and
serve as three sides of said foundation wall for said building;
decoupling any frame or other support from the bottom of the
elongate physical guide means and removing through the fourth,
un-paneled side of the foundation; forming a second plurality of
corrugated structural panels, wherein each panel includes a lower
portion having footing engagement means formed integrally in said
panel, and wherein each panel is formed to be a predetermined
height required at its location between said elongate physical
guide means and said prepared earth, and said footing engagement
means is cut or formed to achieve said foundation design loads,
attaching to said elongate physical guide means along the fourth
side in a manner so as to hang between it and said prepared surface
of the earth of said elongate physical guide means, said second
plurality of structural panels, each of which said structural
panels is of a suitable thickness and strength to support a
corresponding part of a building above, each of which said
structural panels so extends toward earth, in a substantial plane
where said foundation wall is desired, and thereafter placing a
flowable hardenable building material about the lower portion of
each of the attached second plurality of said structural panels and
internal permanent load supporting piers to form a footing
therefore along the fourth side of the elongate physical guide
means, and making each said panel become supported in the flowable
hardenable building material to achieve said design loads, and
serve as the fourth side of said foundation wall for said
building.
2. The method according to claim 1 wherein said at least one
internal permanent load supporting piers comprises a central pier
having a cap plate with at least one securing apertures located at
one end and a base plate located at the opposite end, attached on
an undersurface of the base plate and projecting outward from the
central pier are at least one concrete anchor.
3. The method according to claim 2 wherein said at least one
internal permanent load supporting piers further comprises a pier
height adjustment mechanism.
4. The method according to claim 3 wherein said height adjustment
mechanism is a spilt in the central pier thereby providing two
nesting pipes, an internal pipe and an external pipe, and a series
of radial stop apertures sets that are sized to accept at least one
stop.
Description
FIELD OF THE INVENTION
[0001] The present invention concerns improved methods and devices
for construction of permanent perimeter foundations and anchorage
therefore, especially for pre-situated structures, such as mobile
homes and modular housing. Specifically, the present invention
particularly concerns an improved method using pre-hung corrugated
steel wall panels that is cast-in-place with footing concrete thus
creating a structural foundation wall. The relevant components and
methods allowing this new method are also disclosed.
DESCRIPTION OF PRIOR ART
General Background
[0002] Conventionally, perimeter foundation walls are built from
the bottom up. After a site is prepared, the geometry for that
foundation is typically created by careful measurement and the
setting-up of strings which each define a face of the foundation.
Then the foundation walls are built as close as practical to these
string lines, while attention is paid to level and plumb, et
cetera.
[0003] A procedure such as this is typically followed for a
perimeter foundation of a prefabricated modular structure, which
must subsequently be positioned upon that foundation. Unless a
crane of suitable capacity is available, setting the modular
unit(s) upon the finished foundation involves a difficult process
of sliding, adjusting, lowering, fitting, blocking, and attaching.
Quite often the foundation will have enough deviation in accuracy
to cause problem with fit of the modular unit(s).
[0004] The use of corrugated panels, by themselves, as bearing
walls is a practice known to be utilized in light steel building
construction to a limited degree. Corrugated steel sheet-piles are
common in earth-work as temporary or permanent load-bearing and
retaining walls.
SPECIFIC PRIOR ART
[0005] U.S. Pat. No. 3,820,295, by M. Folley, June 1974, discloses
the use of corrugated steel foundation walls cast into concrete, as
part of a system for constructing a corrugated panel building.
Inverted "T" sections of corrugated panels are set into a trench,
then partially cast into concrete, and finally remain as foundation
walls. These panel "T" assemblies are built of perpendicular
(horizontal) panel elements attached along the bottom edge of the
wall (vertical) panel elements with continuous gusset elements each
side, by welding upon each flute of each corrugated element to each
flange of both continuous gussets. Multiple holes are also placed
in the gussets and the horizontal corrugated panels, apparently to
help allow some flow of the concrete throughout the assemblage.
[0006] The "T" panels disclosed cause considerable and unnecessary
manufacturing expense and storage difficulties, while presenting an
obstruction to the placement of concrete within the confines of a
trench. The continuous "T" element causes difficulty in the
required pre-support of the panels by adding extra weight,
requiring extraordinarily accurate or over-sized footing trenches,
and especially because the horizontal plane presence will catch the
concrete being placed so creating a devastatingly high load upon
the temporary support to the panels.
[0007] It could be assumed that the intended general construction
sequence is conventional, but no disclosure is given for a method
of pre-situating the panels. This aspect of that invention's
foundation is the most important because the panels would have to
be cast in place exactly, straightly, and precisely where required
to be of any use for the continuing construction of the building
above, which is of pre-fabricated elements. In addition, the
complications of the "T" base require that the pre-support also
remain perfectly in place while under the very high loads of
concrete placement. No adjustment or tolerance of significance
would be possible after the panels are cast in-situ.
[0008] The Folley patent emphasis is on the unique construction
above the foundation walls. Based upon the disclosure given, that
foundation method appears to have not succeeded in construction
practice, let alone provide cost efficiency.
[0009] U.S. Pat. No. 6,076,320, by M. Butler, June 2000, the
disclosure of which is hereby fully incorporated by reference,
discloses a perimeter wall foundation that is created by attaching
galvanized-steel corrugated panels to an in-place structure. The
freely having bottom edges of the panels, which have continuous
deformation specific to the enhancement of bearing and anchorage
within concrete, are cast in-situ with footing concrete, so
becoming a cast-in-place perimeter-wall foundation, capable of
residential-scale bearing and shear loadings.
[0010] However, there is still a need for improvements
cast-in-place foundations for use in multi-unit modular buildings
and off-frame prefabricated modular housing.
SUMMARY OF THE INVENTION
[0011] The present invention involves an improved manner of
constructing a perimeter-wall foundation for multi-unit modular
housing and off-frame prefabricated modular housing.
[0012] Prefabricated Modular Structures
[0013] For the case of a pre-fabricated/modular structure, such as
a mobile home, the unit(s) is set upon its own internal piers by
conventional methods, such as utilizing stacked concrete blocks
upon treated-wood or concrete pads. Additional, permanent internal
piers are placed at structural load bearing points, especially for
multi-unit modular buildings. Then any number of
variously-selected-height corrugated panels may be hung from the
perimeter or interior of the unit(s) and so dangling partially into
a trench, contiguously attached, along a location where is desired
a foundation wall. The action of gravity keeps the panels vertical,
then in-situ concrete is placed into the trench, flowing about the
specially deformed lower edge of the panels and permanent internal
piers. The panels and internal permanent piers are adjusted more
finely to vertical before the concrete hardens, so creating a true
foundation wall having superior anchorage to the concrete footing,
with a minimum of effort and cost.
[0014] Site-Built Structures
[0015] For the case of a site-built structure, a linear element is
pre-situated along a location of perimeter or interior line of
support. The element can be initially supported by conventional
means such as wood stakes, or by any suitable proprietary method.
The element can be removable, or be a stay-in-place member such as
a rim-joist. The method of casting-in-place the foundation wall
panels is essentially identical to above, as is the result.
[0016] Thermal Isolation
[0017] For foundations of metal buildings in cold climates, this
invention contemplates improvement of the thermal isolation in
connection of the metal foundation-wall to the metal
building-structure, whereby heat transmission from the metal
structure to its foundation interface is minimized.
[0018] A common practice in metal building construction is to wrap
exterior walls externally with a layer of insulating foam, and
economic factors often dictate sheathing that foam with a
stucco-cement product. This invention provides apparati and method
for allowing this same cost-effective foam-wrap and sheathing
method to occur on the foundation walls, while providing a barrier
preventing capillary transportation up those wall layers, and where
that barrier is also a screed (thickness-guide) for placement of
that stucco-cement.
[0019] System for Variable Sites
[0020] For all embodiments of this invention, variable building
heights and sloping sites can both be addressed by creating a
system of panels of discrete standardized lengths, so that a panel
length can be selected from this system which will suit the needs
of varied foundation height at according to particular location, as
the concrete footing can accommodate the resulting relative
differences of adjacent-stepped panel extension into footing
trenches. This standardization of lengths allows manufacture of a
limited number of distinct parts to serve all foundation wall
cases, within the height limits of that panel strength. To greatly
facilitate the determination of panel lengths and quantities,
especially for sloping sites, software is utilized which accepts
building geometry and relative grade heights as input, and then
provides panel location and quantity by length, as output.
[0021] Labor Savings and Improvement
[0022] This is a perimeter foundation that can be built without
any: geometry definition, concrete forming, form stripping,
foundation pony-wall framing nor sheathing. Besides missing all of
these steps, the method improves: accuracy (by
geometry-duplication), foundation anchorage to concrete-footings,
strength and longevity (over conventional wood-framed ponywalls
that rot and become eaten by insects), ventilation options, and
thermal performance.
[0023] The present invention offers distinct improvement apparati
for supporting load bearing points of modular buildings, especially
multi-unit modular buildings.
[0024] In summary, this foundation offers improved structure for
less cost.
[0025] Specific Objects and Advantages
[0026] More specific objects and advantages of this invention
include the following:
[0027] Provide an improved method allowing construction of the
lowest cost permanent, continuous, perimeter foundation and
permanent internal pier for a multi-unit prefabricated modular
structure or the like. This method allows construction of
foundation walls which provide lateral strength and uplift
anchorage that is superior to any other presently available
proprietary method of founding modular structures.
[0028] Provide an internal pier unit that is used in supporting
load bearing points of a multi-unit prefabricated modular building
system.
[0029] Provide the lowest cost method whereby three sides of the
pre-hung foundation are poured and set, followed by removal of any
off-frame frameworks being removed, followed by the fourth side of
the pre-hung foundation poured and set. Finally, grade backfilling
can occur about the perimeter of a structure that is at or above
grade. This allows installation of a modular structure to
inexpensively be of a low-profile set, while diverting surface
water from the structure.
[0030] Provide a combination structural-wall/permanent internal
pier structure and visually-appealing-screen foundation panel that
can be installed before any footing concrete is placed, thus
avoiding any need to fit panels to planes dimensionally confined by
previous concrete placement, and also providing superior anchorage
of the panels to concrete.
[0031] Provide a single, simple, quickly-installed component that
can provide load bearing support thus providing permanent internal
support of load bearing points, where the footing for the load
bearing component is pour after the load bearing component is
attached to the housing unit.
[0032] The novel features that are considered characteristic of the
invention are set forth with particularity in the appended claims.
The invention itself, however, both as to its structure and its
operation together with the additional object and advantages
thereof will best be understood from the following description of
the preferred embodiment of the present invention when read in
conjunction with the accompanying drawings. Unless specifically
noted, it is intended that the words and phrases in the
specification and claims be given the ordinary and accustomed
meaning to those of ordinary skill in the applicable art or arts.
If any other meaning is intended, the specification will
specifically state that a special meaning is being applied to a
word or phrase. Likewise, the use of the words "function" or
"means" in the Description of Preferred Embodiments is not intended
to indicate a desire to invoke the special provision of 35 U.S.C.
.sctn.112, paragraph 6 to define the invention. To the contrary, if
the provisions of 35 U.S.C. .sctn. 112, paragraph 6, are sought to
be invoked to define the invention(s), the claims will specifically
state the phrases "means for" or "step for" and a function, without
also reciting in such phrases any structure, material, or act in
support of the function. Even when the claims recite a "means for"
or "step for" performing a function, if they also recite any
structure, material or acts in support of that means of step, then
the intention is not to invoke the provisions of 35 U.S.C.
.sctn.112, paragraph 6. Moreover, even if the provisions of 35
U.S.C. .sctn.112, paragraph 6, are invoked to define the
inventions, it is intended that the inventions not be limited only
to the specific structure, material or acts that are described in
the preferred embodiments, but in addition, include any and all
structures, materials or acts that perform the claimed function,
along with any and all known or later-developed equivalent
structures, materials or acts for performing the claimed
function.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 Foundation Panels Ready for Concrete (Prior Art).
[0034] FIG. 2 Foundation Panel Connection to Steel Structure (Prior
Art).
[0035] FIG. 2A Foundation Panel Connection to Steel Structure
Directly (Prior Art).
[0036] FIG. 2B Foundation Panel Cap Connection to Wood Structure
(Prior Art).
[0037] FIG. 2C Foundation Panel Cap/Strip Connection to Wood
Structure (Prior Art).
[0038] FIG. 3 Footing with Concrete and Backfill in Place (Prior
Art).
[0039] FIG. 4 Top-Screened Foundation Panels Ready For Concrete
(Prior Art).
[0040] FIG. 5 Foundation Panel Connection to Wood Modular Structure
(Prior Art).
[0041] FIG. 6 Footing with Concrete in Place, Tab Anchors (Prior
Art).
[0042] FIG. 7 Cut-away View of Installed Foundation Wall Panel
(Prior Art).
[0043] FIG. 8 Section at Panel/Structure Interface (Prior Art).
[0044] FIG. 9 Section at Panel/Footing Interface (Prior Art).
[0045] FIG. 10 Illustrates the initial placement of a multi-modular
building at the placement site.
[0046] FIG. 11 Illustrates the placement of the first module of the
multi-modular building and the initial trenching required by the
present invention to support the join between the two modules.
[0047] FIG. 12 Illustrates the initial trenching required for
support of the join between the two building modules.
[0048] FIG. 13 Illustrates the removal of the first transport truck
and the additional trenching required for support of the periphery
of the first building module.
[0049] FIG. 14 Illustrates the placement of the second building
module of the multi-modular building.
[0050] FIG. 15 Illustrates the removal of the second transport
truck and the additional trenching required for support of the
periphery of the second building module.
[0051] FIG. 16 Illustrates the placement of the internal permanent
piers according to the present invention.
[0052] FIG. 17 Illustrates the placement of the peripheral support
panels.
[0053] FIG. 18 Illustrates the concrete pour for the footer of the
peripheral panes and the internal support piers.
[0054] FIG. 19 Illustrates the removal of the building module
frames and the placement of the last side of panels (with footing
poured).
[0055] FIG. 20 Illustrates a perspective view of the preferred
internal support pier according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0056] Commencing in the drawings FIG. 1 a view of a foundation
panel assembly 11 is shown from the interior of the foundation
perimeter. The supported modular structure is removed for
clarity.
[0057] Foundation panel assembly 11 is primarily made up of a
corrugated foundation panel 12, with some type of component for
attachment of panel 12 to a pre-situated element, such as a
pre-attached perimeter channel 14 shown here. In this case the
attachment component consists of a shear strip 13, which can either
be continuous or of segmental lengths according to installation
needs. For pre-attachment of strip 13 to panel 12, strip should be
of lengths corresponding to panel widths. Break locations in
segmental strips need not align directly with panel breaks, as
overlap of the elements can be beneficial. These elements are
described in detail below.
[0058] Panel 12 is a common galvanized steel corrugated decking
panel such as those commonly used for roof decking or floor decking
in building construction. The particular panel shown is a roof
decking ("B-deck") panel such as is made by any of the commercial
decking manufacturers (Verco, BHP, etc), having a 38 mm (1.5'')
corrugation depth, with corrugation pattern repeating at 152 mm
(6''), and is typically made in 914 mm (36'') panel widths. It is
not essential that this particular choice of decking be used. It is
commonly available at a very competitive price due to large
existing markets, and this panel serves the typical structural
needs of most perimeter foundations, and it has benefit to use as a
ventilated foundation wall in its pattern of corrugation.
[0059] In use as decking, these panels are conventionally oriented
horizontally, as utilized to support an in-situ concrete slab roof.
The "B"-deck panel has an alternating series of relatively narrow
("bottom") and wide ("top") flutes designed for the purposes of
optimizing deck concrete usage. This alternating pattern can be
utilized to advantage as a foundation wall by either maximizing
potential flute-ventilation area (described below for FIG. 4) in
"bottom-out" orientation, or by maximizing surface support to a
covering layer in "top-out" orientation.
[0060] FIG. 1 shows panel 12 orientated vertically, with flutes
vertical, and with the "bottom" (from the perspective of
conventional use as decking material) to the exterior. That is, the
less-wide flutes are to the exterior, and the more-wide flutes are
to the interior. Where panels are left physically exposed to the
exterior, this "bottom-out" orientation also offers the advantage
of avoiding any panel seam edges to the exterior, as in
conventional decking manufacture they are turned toward the deck
"top", which in this case is the interior (crawl-space).
[0061] Lengths (heights) of panel 12 are those to suit given
projects, grades, and specific location along the perimeter. As the
bottom edge of panel 12 is to be cast in concrete, the exact
location of that edge can vary. Thus panels can be of standardized
incremental (stepped) lengths to suit any specific grades
(heights), as described in the invention summary above.
[0062] Most any corrugated panel design which is adequate for the
imposed loads, will serve the purpose of this perimeter foundation
structural wall panel, without the presence of any other foundation
wall structure such as ponywall framing, if the flutes are oriented
vertically as shown. For example, corrugated panels of symmetrical
sinusoidal wave pattern can also be utilized perfectly well as
foundation panels in the manner shown here. Also, the panels can be
of any material and design (uncorrugated) so long as foundation
structural requirements are satisfied. The material chosen as
structurally cost-effective for our product development is ASTM
A446 Grade A (hot-dip-galvanized coil-sheet-steel), where the yield
strength is at least 225 MPa (33 KSI). Most of the manufacturers of
"B-deck" typically provide it with a yield strength of 258 MPa (38
KSI). A galvanizing of the standard "G-90" zinc weight, as opposed
to the more common "G-60", is preferred for the materials of panel
assembly 11 installed in damp environments.
[0063] For modular housing units imposing significant gravity loads
as well as lateral loads, steel panel 12 is typically of a
thickness of 1.10 mm (18 gage) or as thick as 1.44 mm (16 gage)
material. For manufactured homes built to the Department of Housing
and Urban Development Code (HUD Code) commonly referred to as
"mobile homes", which are primarily supported along the interior
chassis, panel 12 at the perimeter would then be subject primarily
to lateral loads with only relatively minor gravity loads, or
possibly roof snow loads. It could then be as light as about 0.720
mm (22 gage), depending upon specific lateral load, any soil
retaining forces, snow loads, and geometry factors.
[0064] Panel assembly (and connection components) 11 exterior
surfaces are best protected, in addition to the galvanizing, by an
application of roofing tar (room temperature or hot), or water
emulsified coal tar, or the like. The tar can be field applied, or
the panels can be factory coated. An immediately placed, subsequent
covering of sand, can provide inexpensive texture finish as it
binds into the tar. The combination of these two provide long term
protection of the panel combined with an aesthetically pleasing, UV
resistant, foundation wall finish. Any color of paint can of course
be applied over. Alternatively, any compatible texture/paint
product can be applied over the cured tar.
[0065] Panel 12 is best made in incremental heights (lengths) for
reasons described below, starting with a practical minimum height
of very roughly 300 mm (12''). Individual panel width is not
crucial, it can be an industry standard for roof decking panels
such as that of 900 mm (36''), thus providing the benefits of
conformity with presently available material.
[0066] Analysis of the structural properties and buckling strength
of this type of decking can be quite complex, considering the
combination of loadings as: a bearing wall, a beam element from
out-of-plane loads such as those by retained earth, and in-plane
shear loads. Decking panel testing performed at West Virginia
University for combined wall-bearing parallel to the flutes and
out-of-plane loadings, have shown that the specimen follow theory
closely enough to confirm validity of structural formulae developed
by the American Iron and Steel Institute (AISI) which have been
adopted by the model building codes. The shear force within the
limits of building-code-approved decking shear-strength tables can
be safely superimposed, as the shear-action within these limits
contributes very little to overall element stress for panels of
this type. The 1.14 mm (18 gage) "B-deck" panels have a
code-allowed shear-strength (while under maximum flexure) of
approximately 1400 Kg force per running meter (1000 PLF), which is
about four times that of common plywood shear panels that are
conventionally placed upon conventional wood-framed foundation
ponywalls.
[0067] Presently the structural safety of for this new use of these
panels has been justified by extensive calculation based upon the
AISI formulae. The strength of the panel connection and the
concrete footing itself is justified by similar calculation based
upon known properties of concrete. A simple calculation for the
bearing strength of the panel at the footing follows. It is
included to show that the panel with the simple deformation pattern
disclosed is adequate for residential scale bearing loads without
the need for some sort of an attached horizontal element such as
Folley's "T" described in "Prior Art" above.
[0068] FIGS. 1 and 6 show that panel 12 has a series of a tab 46
which are created by two cuts made from the bottom of panel 12, and
at diverging directions so that each tab has two tapered sides.
Before the placement of concrete, tab 46 should be bent
out-of-plane with panel 12 by at least very roughly about
5.degree., but preferably about 45 to 90.degree., for reasons
discussed below. The divergence of the cuts creating the taper of
tab 46 allows panels to stack after tabs are bent. More
importantly, the divergence of the tab cuts provides a remaining
flute foot 48 with two of a flute foot anchor 50 where each anchor
50 has an edge with the reverse of this same taper. This resulting
reverse taper of each anchor 50 provides excellent withdrawal
strength for each cast-in-concrete flute foot 48. Our development
has shown that a 5.degree. taper on these cuts serves well for both
anchorage and panel nesting, but this angle can vary considerably
for both purposes.
[0069] The series of tab 46 provides support to bottom extent of
panel 12 for downward vertical loads. Considering that in this
loading condition, a resulting compression zone of concrete can be
considered to have an upper boundary, each side of the loading
element, sloping at 45.degree. downward. Thus tab 46 best serves
bearing purposes when bent at least 45.degree. so as to remain at
the top of this compression zone, but when bent over 90.degree. tab
46 would impart a lateral component contributing to a possible
longitudinal the cracking of the concrete. Given that in-situ
concrete is can be considered to be of at least 13.6 MPa (2000 PSI)
design strength, each approximately 38 mm.times.80 mm tab can bear
about 800 Kg force (1800 lb), if only 20% of the bearing area is
considered effective (that nearest the panel plane). This equates
to 2650 Kg force per running Meter of perimeter (3600 PLF).
Soil/footing design loading is typically a third of that for
residential construction, so this panel deformation pattern is
clearly adequate for residential-scale bearing-wall loads.
[0070] Continuing in the drawings FIGS. 1 and 3, alternatively,
panel 12' connection to subsequently placed in-situ concrete can be
enhanced with a series of a large aperture 40, in lieu of the
series of tabs and feet described above. Aperture 40 must be of
adequate dimension and repetition to allow the bond of concrete to
occur across panel plane, thus providing a stronger anchorage to
footing. Round holes are best of a diameter that is nearly half
that of their spacing, in order to provide adequate concrete bond.
This frictional attachment to the concrete footing is considerable
(and is ignored in the informal loading calculation above).
[0071] Simple-cut-edge panels (FIG. 4) can be shown to have
adequate bearing and uplift strength in the concrete footings in
many situations.
[0072] A length of reinforcing bar 42 can be secured adjacently to
panel 12' with a wire tie 38, or the like. Tie 38 can be secured
around a flute via apertures 40. For panel 12, rebar can also tie
to flute foot 48 via the diverging cuts discussed above. Again,
this divergence helps, in this case by keeping tie 38 from slipping
off foot 48.
[0073] The shear connections between adjacent panels can be the
conventional steel-decking male-female seam connections, and so are
not shown here. It is worth noting that conventional welded
connections are best avoided here in that corrosion would be
promoted at those locations. Also, foundation-wall panel
access/orientation circumstances can make conventional
"button-punching" of the male-female seams more difficult than it
is for the conventional (horizontal) configuration of the decking.
Alternatively, common panel male-female seam connections can be
simply inserted, but left uncrimped, where shear-loading
requirements will allow. An optimal shear interconnection for
foundation-wall utilization of the panels is that made by use of an
appropriate adhesive placed along the male-female seam connections.
This adhesive can be most any common "construction adhesive"
compound, or an urethane type adhesive-caulk, or like compound
which adheres to sheet steel. This type of panel interconnection
can seal one or both panel edges (ungalvanized) from potential
atmospheric corrosion, and can prevent possible moisture intrusion
through the foundation wall at the panel seams.
[0074] Panels can of course simply be overlapped, and just fastened
together if necessary, such as is commonly done with
sinusoidal-pattern corrugated-roofing material. To accommodate this
type of panel lap, pre-attached connector strip 13 must of course
be appropriately shorter than the panel 12 to which it is
connected.
[0075] Continuing in the drawings, FIGS. 1 and 2, panel 11 connects
along a line of perimeter 26. Perimeter 26 can be the outer
perimeter surface of any pre-situated object, such as: a modular
structure (built per Model Building Codes), mobile home (HUD Code),
proprietary pre-situated floor grid (such as the present inventor's
U.S. Pat. No. 5,564,235), or any other object that physically
defines the geometry of a building perimeter, where that geometry
can be exploited directly to physically define the perimeter of a
supporting foundation. Element 26 can be a single board, positioned
as would be a first form-board in the construction of conventional
foundation wall forms, with the difference here being that this
board is the only one necessary to situate, and it can subsequently
be left-in-place to become a permanent floor-framing-member such as
a rim-joist.
[0076] Shear strip 13 is a galvanized steel strip of about 1.44 mm
(16 gage) or the like that serves the purpose of attaching panel 12
to a pre-attached perimeter channel 14. The profile of channel 14
can vary considerably from that shown here, while the same concept
of attachment of panels remains. Where a lower flange 23 of channel
is less wide than panel 12 is thick, ventilation into the
crawl-space is possible through the tops of the panel flutes, and
so a continuous screen can be inserted between panel 12 and flange
23 at panel installation, if desired, similar to the screen
arrangement (shown in FIGS. 4 and 5). If ventilation is required
where flange 23 is wider than panel 12 is thick, appropriate
description follows below (for FIGS. 4 and 5).
[0077] Bottom flange 23 can also be considered the bottom of any
like perimeter element. It can be the bottom edge of a wood nailer
that is often found at the perimeter of wood-framed mobile home
undersides, or the bottom edge of the rim-joist described
above.
[0078] Continuing in the drawings FIG. 2A, shear strip 13 or the
like can be avoided if a perimeter channel 14' or the like, with a
simple vertical flange, is utilized at pre-situated structure
perimeter 26. Channel 14' can be field installed to a typical
modular structure in lieu of strip 13, or it could be factory
installed by a modular manufacturer in lieu of channel 14 or nailer
28 in anticipation of this foundation installation.
[0079] Continuing in the drawings FIG. 2B, an example of a cap
channel 54 is shown. Cap 54 is typically of about 1.44 mm (16 gage)
thickness galvanized steel. It can be factory connected to flutes
each side of panel 12, and so would be of a length slightly less
than each panel. Cap provides bearing surface area for wood
structures, and a means of attachment from below.
[0080] FIG. 2C shows a slightly more involved cap/strip channel 56,
which is otherwise like cap 54. This is one version of the many
possibilities for simple folded steel members that connect panels
to building structures while providing bearing, shear transfer, and
uplift load requirements.
[0081] Continuing in drawings FIGS. 4, 5, and 6, a panel assembly
11' with continuous top ventilation built-in, is shown.
[0082] A pre-attached (factory attached) perimeter wood nailer 28,
which is common to most wood-constructed modular-structures, is
shown above a vented foundation panel assembly 11'. Any
pre-situated member can substitute for nailer 28 for this
embodiment of panel installation. Assembly 11' includes a
screened-shear-strip-assembly 30 along the interface between panel
12 and member 28.
[0083] Screened assembly 30 is of a bearing channel 32, a shear
strip 13', and a screen 34. Assembly 30 can be field-attached or
factory-attached to panel 12. For any pre-attachment, any length of
assembly 30 must be less than panel 12, for convenience of
installation. Bearing channel 32 is a cold-formed galvanized-steel
section or the like. It provides a bearing surface for nailer 28
and creates a space, approximately 18 mm (3/4'') high, between
nailer and top of panel 12, allowing ventilation to occur via the
vertically oriented flutes of panel 12. A continuous vent slot is
so created, which would otherwise be choked off by presence of
nailer 28.
[0084] Bearing channel 32 upper flange can be made wider than the
bottom flange, so that flute-ventilation area is decreased less by
the channel presence, while bearing area presented to nailer 28 is
increased. If an asymmetrical channel design is chosen, the effects
of resulting eccentricity must be considered in the design of
connections to panel 12 and to nailer 28.
[0085] A screen 34 can be utilized to prevent vermin access to a
crawl space foundation via the vents created by the flutes in panel
12. Screen 34 can be galvanized or plastic. A heavily galvanized
version has an advantage in that the presence of the extra zinc
will create a field of corrosion protection for the cut edge of
panel 12, although this edge is best protected with at least a
spray-coating of zinc-rich paint anyway. Screen 34 is best attached
to strip 13' by placing it between strip 13' and channel 32, as
strip is factory attached to channel with a series of a rivet 20,
or metal-deformity press-connections such as the "Tog-L-Loc"
patented metal joining system, registered trademark of the BTM
corporation of Marysville, Mich. Any other appropriate factory-made
connections can of course be considered, for this or other panel
assembly attachments.
[0086] Screened assembly typically comes in convenient lengths for
field installation of panels 12, and can be a length corresponding
to each panel width, aligning with panel seams, and with
appropriate end clearances, so that each panel assembly 11' can be
installed as a unit, contiguously. Alternatively, assembly 11'
segment joints can stagger, that is, strip 13 joints can exist
offset of panel 12 seams, while channel 32 joints align with panel
12 seams. This allows benefit of shear strip 13 overlap while
avoiding detriment of bearing channel 32 extension, which if
present, must be considered to have to be inserted between the
previous panel top and member 28. Irregularities of member 28 and
the previous-adjacent panel installation make this insertion
potentially impossible.
[0087] Screen 34 can have a hem 36 that provides linearity and
weight, thus keeping screen consistently close enough to flute ends
to serve its purpose. Alternatively, screen can have a fold, and
this fold can have an upward bend of very approximately 12 mm high
which serves to hold up any sagging plastic vapor barrier which may
be factory-installed underneath a manufactured home, thus
preventing potential blockage to perimeter vent area.
[0088] Continuing in the drawings FIG. 7, a view of perimeter
foundation panel assembly 11', of an embodiment designed thermal
efficiency, is shown from the exterior.
[0089] This panel assembly 11' is of corrugated foundation panel
12, as described for FIG. 1, with a special strip connector
assembly 15 attached along the top edge. This panel 12 orientation
differs from that of previous figures in that the decking panel 12
is shown "top" side out (from the perspective of the use as decking
material). This orientation simply offers more flat steel surface
for the support of surface coverings, as could be utilized to
optimize thermal performance. This orientation is not critical, nor
is the use of this particular type of panel, as described for FIG.
1. The point is that many variations in panel configuration will
serve the purposes of the cast-in-place structural panel and its
thermally efficient embodiments.
[0090] With present material technology, panel 12 is structurally
most cost-efficient if of (heat conducting) steel, thus avoidance
of thermal bridging at strip 15 is certainly warranted for metal
buildings to prevent heat loss in cold climates. For wood
structures, the thermal isolation features at the foundation panel
11 connection are probably not necessary, but the thermal
insulation from the exterior to the crawl-space, and the labor
minimization and other design efficiencies of this system still
pertain.
[0091] FIG. 7 and FIG. 8
[0092] Panel 11' is shown attached to a metal perimeter member 21
of a pre-situated metal structure. The perimeter member 21 shown
here specifically is a light gage, approximately 1.44 mm (16 gage)
thick, steel channel or "track" section that is at the periphery of
a pre-situated floor grid system. This perimeter member 21 can vary
considerably. A field floor-framing member 29 is covered with a
flooring panel 31. Some type of a wall framing 33 typically
attaches along the perimeter.
[0093] In an ideally thermally efficient embodiment, panels are
sheathed with a rigid insulating foam 25, such as polystyrene bead
or isocyanate or any other suitable type, which subsequently is
covered with something such as a stucco layer 64 for weather and
moisture protection. For foundation-walls below-grade at wet sites,
foam 25' can appropriately be sub-grade quality, such as closed
cell urethane, extruded polystyrene, or the like. This type of a
foam and stucco-product finish of course provides optimum
protection and insulation for the foundation wall. It is
cost-effective to stucco-sheath here if a stucco type covering is
to be applied over the structure exterior anyway. Foam is
conventionally installed in this manner over the exterior of metal
framing in cold climates. Stucco lath wire and its attachment to
thin steel is a contemporary practice, the only variation here is
that foundation wall stucco lath is attached to panel 12 rather
than to wall studs as above. This conventional stucco wire
attachment is not part of this invention, and is not shown here for
clarity.
[0094] Alternatively, the insulated panels can be of contemporary
structural-insulated-wall-panels manufactured with outer
laminations of metal and with expanded foam inside. These panels
are commonly made with relatively minor surface fluting or even
flat.
[0095] Of course where a crawl space is thermally insulated from
the exterior, venting should be omitted or at least controlled.
Minimal vent openings which are automatically controlled to close
during cold temperatures is a conventional construction technology
which is beneficial to the present foundation designs. The presence
of a vapor barrier 70 on grade (FIG. 9) is generally a necessary
element to any thermally-controlled crawl-space design.
[0096] If foundation wall is to have other finishes, or no finish
or insulation at all, is given to panel 11, then thermal isolation
at panel connection to structure above becomes more important in
cold climates.
[0097] Panel 11 is best made in incremental heights (lengths) and
is connected as described above for FIG. 1.
[0098] Strip connector assembly 15 can vary in construction. The
embodiment shown in FIG. 7 and FIG. 8 is made up of four primary
elements: the shear strip 13, a bearing channel 20, a thermal
isolator strip 27, and a screed/waterstop 19.
[0099] Strip 13 is of 1.44 mm (16 gage) galvanized steel such as
type ASTM A446 with a yield strength of 340 MPa (50 ksi), or the
like, depending upon specific load and force considerations
discussed further below. Strip 13 must be of a width that spans any
distance between panel 12 and flange 23 and allows overlap with
panel 12 minimally sufficient for the connection of a (field or
factory installed) fastener 16, and overlap at perimeter 21
minimally sufficient for the connection of a field fastener 18.
Each of these distances should be approximately a minimum of 12 mm
(0.5'') for the practical considerations of making connections.
[0100] Bearing channel 20 is appropriately of 1.44 (16 gage) or
1.81 mm (14 gage) thickness galvanized steel of similar quality to
the other like components, but again thickness and strength
requirements will vary according to geometry and loads, discussed
further below. Bearing channel vertical face 39 is of a dimension
necessary to create a space below perimeter 21 for rigid insulating
foam 25. Foam is of a thickness necessary for underfloor insulation
for given circumstances, with or without any batt insulation
between floor framing members (With underfloor foam 25, thermal
conductance through metal framing members is not significant). Face
39 does have a maximum practical height that will vary considerably
according to loads. A height of approximately 25 mm to 40 mm (1''
to 1.5'') suits underfloor foam insulation requirements and is
generally structurally feasible.
[0101] Ledger flange 37 is of a minimum practical dimension that
allows suitable bearing of structure above. This minimum dimension
is roughly 10 mm (3/8''), depending upon size and weight of
structure above, as well as the choice of material for isolating
strip, due to its variations in bearing capacity, cost, and thermal
efficiency. The practical considerations of this dimension, and
that of the overlapping fastening edge of strip 13, are those
related to the field installation of the panels under imperfect
site conditions by potentially hasty workers.
[0102] A cover flange 41 is dimensioned to bear upon the top edge
of panel 12 of given manufacture. Lip 43 acts to support the inside
surface of panel directly, from out-of-plane loads, such as soil
backfill 52. This reduces fastener 16 prying and tension force
criteria at panel somewhat and deformation to panel 12 of a given
weight from given loads, allowing lighter weight panel selection.
These out-of-plane loads cause significant shear force to fastener
18, due to cantilever geometry of assembly 15. Thus panel assembly
11 fastener installation, quantity of fasteners, and bearing strip
strength, must take out-of-plane loads into account. Lip 43 does
not reduce tension force at fasteners 16, connecting strip 13 to
bearing channel 20, thus the criteria for amount and location of
fasteners 16 that connect strip 13 to bearing channel 20 depend
upon this out-of-plane loading. Two horizontal rows of this
fastener would be justified for a given height of channel 20, the
amount of out-of-plane load, and bearing channel thickness, et
cetera.
[0103] A more detailed discussion of the structural considerations
of these connections and of the vertical column aspect of strip 15
follows below in the description of an insulating plastic
connecting strip of FIG. 10D. These somewhat subtle structural
considerations are more significant for a relatively expensive
insulating plastic material structural element, than they are for
relatively inexpensive and stronger steel structural elements.
[0104] The combined contact area to structure perimeter 21 of both
strip 13 and ledge 37 must be minimized to reduce the surface area
that must be thermally isolated, thus minimizing both conductive
and radiant heat exchange for a given expenditure in relatively
expensive isolator material.
[0105] Isolator strip 27 can be one of many materials, each having
some tradeoff with regard to cost and efficiency. The actual
isolating material is not part of this invention. The present
invention discloses a structural foundation wall connection design
that minimizes contact area with a metal structure, thus giving the
opportunity to cost effectively use relatively more expensive
materials as isolators. It is anticipated that many technological
breakthroughs in the field of thermal isolators are impending, and
that widespread commercial availability of highly efficient such
materials will soon follow. Heat loss is proportional to this
contact area, for any type of insulating material, so this
invention has improvement in use with more common, less efficient
isolators.
[0106] For situations where the supported structure does not impose
tremendous concentrated bearing loads at any point along the
perimeter, isolating strip 27 can be of an adhesive foam strip, or
possibly two strips for ease of installation, one along ledge 37
and one along strip 13. Isolating strip 27 can be of relatively
high density (50 shore A) closed cell vinyl foam such as 3M.TM.
4500 series foam tape which has minimal water absorption
properties. This is a relatively economical isolator. It has a
conductivity (u) of 0.043 W/m*K, which is about one thousandth the
conductivity of steel at 46 W/m*K, and so it presents a virtual
"brick wall" to conductive heat loss through the steel structure. A
thickness of 3 mm (0.125'') presents an R value of 0.41
ft.sup.2*F*h/Btu, which is low compared to fiberglass batt
insulation of a few inches thick, but the area presenting heat loss
is very small. Where this juncture is within a perimeter-insulated
controlled-vented crawl space, the temperature difference between
the steel elements is rarely going to exceed about 20.degree.
Fahrenheit, so the heat loss is less than is for a 230 mm (9'')
wide strip of R20 insulated exterior wall assembly at a 40.degree.
Fahrenheit temperature difference. Thus the total heat loss through
the foundation can be shown to be relatively minimal, even
utilizing low-cost isolators.
[0107] Controlled-vented crawl spaces are typically minimally
vented with heat-sensitive shuttered vents that remain closed
during cold periods to avoid heat loss. This type of vent can be
utilized with this crawl space foundation, by making an appropriate
vent installation at a penetration in panel 12 where necessary.
[0108] The nature of structure perimeter 21 and panel 11 interface
is such that concentrated loads are spread out over long lengths of
perimeter, so that a fairly compressible isolating strip 27 can be
utilized at ledge 37 typically, without concern about effects of
isolator "bottoming out" from concentrated loads. Each field
fastener 18 would typically be capable of roughly 1 kN of shear
through vertical face of isolator 27, and thus can generally be
expected accommodate the gravity loads in shear. The
compressibility, or stiffness, of isolator should be such that it
will start to take up relatively large downward loads well before
fastener 18 connections start to fail, considering that some amount
shear-slip will occur at the fasteners 16 connecting into ductile
steel through the thickness of a soft isolator.
[0109] Presently available firm-hardness isolator materials
include: polyvinyl such as contemporary vinyl windows and vinyl
stucco-screeds are made of; "tire inner-tube rubber" or the like;
silicone-treated ceramic fabric tape (such as 3M.TM. Nextel.TM. 312
fabric of Alumina-Boria-Silica); and silicone-treated fiberglass
tape, about 3 mm (0.125'') thick. Because the isolator can get wet
during construction, and will frequently be at the dew point in
damp climates, water-absorbing materials must be avoided. The
silicone-treated ceramics and fiberglass fabrics are more costly
for a given amount of thermal isolation and insulation, but they
allow far higher bearing force without detrimental compression.
[0110] Screed/waterstop 19 is of non-heat-conductive material that
can provide enough structure to withstand the stucco-type finish
process while remaining adequately true to act as a screed.
Polyvinyl (such as UV-resistant rigid reinforced PVC extrusion)
sections are commonly utilized for stucco screeding presently; and,
either that or a pultruded UV-resistant glass-fiber-reinforced
polyester-resin section will work here as well. Screed 19 also
serves as a waterstop that breaks capillary and hygroscopic
moisture transportation within either foam 25' or stucco, and along
foam-to-stucco interface. Capillary transportation will not occur
as greatly at foam-to-panel interface, because panel 12 contact
with foam 25' is intermittent. However, setting screed 19 in caulk
or tape at panel 12 surface will terminate any upward capillary
action at the foam-to-panel interface, which may still be present
at screed height.
[0111] Screed 19 has a fastening lip 58 that is kept in place by
the factory connection of strip 13 to panel 12 and so serves to
thermally isolate panel from strip 13. A horizontal flange 60 is of
a width matching combined foam and stucco thickness, as its outer
edge physically defines the stucco surface plane. An optional
return flange 62 is of a width that returns back to outer surface
of foam 25', to hold top edge of that foam in place, thus aiding
installation. Return 62 also acts as a keeper for a spline/barrier
72, which is of similar material as screed 19, but sufficiently
slender to fit within screed return. Spline is preferably less than
about 1.5 mm thick, but this depends upon inside radius of
horizontal flange 60 to return 62 "bend". Spline 72 serves to keep
each screed 19 aligned to the adjacent other at panel 11 joints.
Spline 72 substitute-performs screed 19 waterstop function at panel
joints, and so preferably is of a width that fits fairly snugly to
panel outer flute face.
[0112] Screed 19 can be field-installed, as can the entire
insulating assemblage, to improve panel nesting and space
requirements until installed.
[0113] The heat loss via conduction through the metal fasteners
located along either edge of strip 13, while difficult to
calculate, will certainly contribute significantly to the amount of
heat transfer through isolator 27. A solution to this loss is to
replace the composite-element strip 15 with an element consisting
solely of insulating-structural material, as is discussed below for
FIGS. 10B through 10D.
[0114] FIG. 7 and FIG. 9
[0115] The bottom of panel 11' has a deformation pattern along its
bottom as described for FIG. 1.
[0116] A subsequently-placed backfilled-soil-material 52 is shown
at the exterior side of the foundation wall (FIG. 9), for the site
drainage, aesthetics, and thermal insulation to the footing.
Subsequently placed polyethylene vapor barrier 70 is show over the
soil at the inside of foundation wall to limit moisture vapor
introduction from earth to the interior of a controlled vented, or
unvented underfloor foundation space. Barrier 70 is sealed along
edges with sand, or the like. Neither backfill 52 nor barrier 70
are necessary elements of this invention (although many building
jurisdictions require the vapor barrier for a controlled-vented
crawl space).
[0117] A length of reinforcing bar 42 can be secured adjacently to
panel 11 with a wire tie, or the like, about top of foot 48. Tie
wire not shown here for clarity.
[0118] FIGS. 10A through 10D show other embodiments of thermally
isolating strip connector assembly 15 and the like. Features
differing to the preceding are discussed.
[0119] FIG. 10A
[0120] The modified strip connector assembly 15' is for
applications where a stucco finish is not being used, and so has no
screed 19 (FIG. 8). Strip assembly 15' does have a thermal isolator
bearing strip 74 at panel 12 to bearing strip 20 interface.
Isolator 74 can be of identical material that isolator 27 is of,
except that isolator 74 location at the cut ends of panel 12 is a
consideration for tear resistance. The row of fastener 16 can be
made strong enough to transfer all of gravity perimeter 21 gravity
load to panel 12, if necessary. If panel 12 is not to be covered
with foam or even cladding, then isolator 74 serves to seal bearing
channel 20 to panel 12 joint from infiltration where necessary.
Also, isolator 74 becomes that much more necessary in addition to
isolator 27, due to greater temperature differences at this
interface without the insulation or even cladding over panel
12.
[0121] FIG. 10B
[0122] Where a recess for supporting foam is not necessary or
desired, a strip connector assembly 86 without foam space is
appropriate. Assembly 86 consists of: shear strip 13' (which is of
a lessor width due to the lack of a foam space); a thermal isolator
strip 76 that matches strip 13'; and a thermal isolator bearing
strip 74' that matches panel 12 pattern thickness.
[0123] Isolator 76 can pre-adhere to strip 13' for convenience.
Bearing isolator 74' has further concern about localized stress and
tears than isolator 74, due to specific floor framing members
potentially pressing flange 23 downward at particular locations. In
addition, isolator 74' is acting alone without the benefit of the
foam space and isolator 27 above. For these two reasons, isolator
74' should be more substantial than isolator 74, and in most cases
cannot be of solely a soft foam type product. Isolator 74' is
suitably of a solid polyvinyl material of least 3 mm (0.125'')
thick, or the like. A hard rubber product will seal off air
infiltration at the top of panel flutes.
[0124] FIG. 10C
[0125] To effectively eliminate heat conduction from the row of
fasteners 18 to the row of fastener 16, a strip connector of
insulating material 80 is utilized. Strip connector 80 replaces
both strip 13' and isolator 76 with a structural vertical strip
element 82, and it replaces bearing strip 74' with an integral
thermal isolator bearing strip 84. Strip element 82 and bearing
isolator 84 do not have to be integral as shown, but can be each of
separate extrusions and of different materials. If integral,
isolator 84 is physically kept in place at the top of panel 12
before panel installation. Integral connector 80 is appropriately
of high quality RPVC extrusion, or of construction-structural
quality glass-fiber-reinforced plastic pultrusion such as
Extren.RTM. by Ryerson Steel Inc. of Chicago, Ill. In either case,
connector 80 must be of a high enough connection strength to
satisfy requirements of fastener 16 and fastener 18 for given
prescribed lateral loading conditions, et cetera. Vertical strip
element 82 must be capable of resisting the greater of either
prescribed or actual uplift forces at structure perimeter 21. For
this reasons and that of a potential prying action resulting from
backfill loads (described more fully below), strip 82 typically
cannot be of a solely unidirectionally-reinforced plastic, such as
"fiberglass" battens are typically made of.
[0126] FIG. 10D
[0127] The best performing thermal isolator is one entirely of
insulating material that also creates an insulating space that can
be filled with foam. A strip connector of insulating material 88
with a foam space is consists of entirely integral elements of the
same extrusion. Strip connector 88 is also best of material such as
high quality RPVC or GRP as described just above. Because these
materials are expensive compared to steel, and connector strip 88
is relatively substantial in configuration, careful structural
analysis of it is justified to minimize sectional area and
therefore cost. As well as providing adequate fastener connection
strength as described above, it must have adequate flexural
strength, perpendicular to its longitudinal axis, to accommodate
forces described below. Reinforcement within plastic section thus
cannot be solely unidirectional, as a following discussion treats
more thoroughly.
[0128] Elements of strip connector 88 at the connection to
structure above are a vertical fastening flange 92 and a horizontal
bearing flange 94.
[0129] Due to out of plane, primarily inward, loads to panel from
soil backfill, et cetera, strip connector 88 tends to be rotated
inwardly about the bottom of perimeter 21. This causes fastening
flange 92 to experience a downward force promoting tear out type
failure at any fastener 18 location, thus a solely unidirectionally
reinforced plastic, such as "fiberglass battens" are typically made
of, would be structurally inadequate for fastening flange 92, any
possible uplift forces on structure perimeter 21
notwithstanding.
[0130] This rotational force on strip connector 88 causes downward
force to bearing flange 94, the fulcrum of the rotational action.
This bearing pressure is in addition to, and conceivably exceeds,
gravity loads. Thus bearing flange 94 must be designed as a short
cantilever for this combined loading criteria.
[0131] Insulating strip connector 88 connects to panel 12 with
fasteners 16 at a vertical fastening flange 93, and also bears on
panel 12 at a horizontal bearing/closure flange 96. Both fastening
flange 93 and closure flange 96 must consider much of the same
structural requirements discussed above for fastening flange 92 and
bearing flange 94 respectively, except that inwardly-applied
out-of-plane loads from backfill do not increase these forces.
These loads would cause prying action at the connections made with
fastener 16 without the presence of a closure lip 98. Entire
cantilever distance of closure flange 96 should not be considered
in determining bending force at its root because panel 12 can
easily take all load at its outer face, and so flange stress-relief
strain is acceptable.
[0132] The main body of connector strip 88 is a vertical structural
web 90. Web 90 must be capable of withstanding flexural forces
described above, combined with vertical-axial and flexural forces
from eccentrically imposed gravity loads from structure perimeter
21 and flange 23. Thus web 90 can be thought of as a column
stabilized from collapse by virtue of its "fixed-end" moment
connections. The upper fixed moment connection is good only for
inwardly-imposed out-of-plane loads to panel 12, unless bearing
flange 94 is fastened to structure flange 23.
[0133] An optional integral-screed/waterstop flange 95 would be of
a projecting dimension as required in description of
screed/waterstop horizontal flange 80 (FIG. 8). Integral waterstop
flange 95 would be tend to be more substantial than an element such
as flange 80 because it is part of a structural extrusion, and so
alignment of flange 95 outer edge at panel 11 joints is less of a
concern. Spline/Barrier 72 (FIG. 10D) is not required for
alignment, but something like it (but external), or caulk, may
still be required to seal waterstop 95 at the joints for wet
sites.
[0134] Screed/waterstop flange 95 can have a return flange such as
flange 62 as does screed/waterstop 19 (FIG. 8), for the same
purposes. Or, screed/waterstop 19 can be substituted for flange 95.
Flange 95 can of course be included on connector 80 (FIG. 10C).
[0135] Operation
[0136] FIGS. 11 through 19
[0137] An improvement necessary for supporting large or multi-unit
modular structures are internal permanent load supporting piers
110. The internal permanent piers 110 comprise a central pier 115,
which is preferably a standard pipe, having a cap plate 120 with at
least one securing apertures 121, preferably four, located at one
end 111 and a base plate 125 located at the opposite end 112.
Attached on an undersurface 126 of the base plate 125 and
projecting outward from the central pier 115 are at least one
concrete anchor 130, preferably four concrete anchors. This
embodiment is a fixed length pier where the central pier 115 has no
length variability.
[0138] In another preferred embodiment, there is height
adjustability of the internal permanent piers 110. Accordingly
there is a pier height adjustment mechanism 140. In one embodiment,
the pier height adjustment mechanism 140 is provided by splitting
the central pier 115 into two nesting pipes, an internal pipe 115'
and an external pipe 115''. Located in the internal pipe 115' are a
series of radial stop aperture sets 116 which are sized to accept
at least one stop 117. Thus, by placing at stop 117 into any one of
the set of radial stop apertures 116 one is able to adjust the
height of the internal permanent piers 110 to any reasonable height
desired.
[0139] The internal permanent load supporting piers 110 are
preplaced under modular building floor joists at points of load in
large or multi-unit modular structures. These internal permanent
piers 110 are attached to the floor joists via bolts (not shown)
that are driven through the securing apertures 121 located in the
cap plate 120 and into the building frame or floor joists. The at
least one concrete anchors 130 are placed into a trench that is
predug under the building load location. Concrete is then poured
into the trench and allowed to cure, thereby providing support
along the internal load line(s).
[0140] This foundation method varies according to conditions of
support during and after modular-structure or floor-member
installation. The foundation panel necessary strength and thickness
will change according to types and amounts of superimposed loads,
and will change to a lesser degree according to panel height for
given loads. Also, the internal permanent pier necessary strength
and central pier thickness and diameter will change according to
types and amounts of superimposed loads, and will change to a less
degree according to central pier height for given loads.
[0141] To determine the necessary length for each panel and
internal permanent pier in order to create a structural-foundation
kit, one must have site grade information (as trenched), and know
the height at which the structure will be set. A simple floor plan
with dimensions down to grade at certain intervals, building
corners and at breaks in grade, will suffice. Panel and pier
lengths should be such that they clear the bottom of the trench by
at least about 100 mm (4'') to allow footing in-situ concrete
placement from only the outside. A minimum clearance of 150 mm
(6'') makes concrete placement from the outside only easier.
[0142] Mobile home (HUD code home) permanent installations can of
course be made without a foundation perimeter of genuine structure,
where State-approved moment-resisting-pier and/or cable-anchoring
systems are utilized at the chassis beams. These systems do not
meet the model building codes (such as for site-built structures)
however, as does the present invention.
[0143] A perimeter-structure of the present invention, which is
only partially about the perimeter, would be acceptable
structurally in most situations in lieu of internal lateral/uplift
support systems, according to typical criteria of State-approvals.
Panels set only or mostly at locations where backfill is desired
anyway, and/or where required structurally, is a viable
cost-optimized foundation design. A continuous structural-paneled
perimeter is generally preferred, however, for reasons of: allowing
backfill grading, keeping out surface water and rain, heat loss
control, fire safety, visual screen, allowing low-profile sets, and
satisfying model building codes, et cetera.
[0144] Mobile homes generally support most or all of their weight
via interior supports, which can be simple-supports, such as
concrete-block or steel-tripod pier supports, at the chassis beams.
Thus the structural-perimeter panels of the present invention can
usually be relatively thinner and weaker than that required for
normal site-built bearing walls. In general the mobile home panels
are preferably installed after all permanent interior
simple-supports have been completed, in other words, the mobile
home is set first. Keeping in mind that sequence can vary, this
method would typically be as follows:
[0145] Prepare site as required for interior and perimeter
footings. Temporary interior supports, interior permanent piers and
footing design can be of any conventional of proprietary means, and
simple support is sufficient. Trenching for the paneled perimeter
and permanent piers can be imprecise, so that layout effort is
easy. Interior and perimeter trenches can conceivably be omitted
altogether if the soil conditions and prevalent codes allow, and
the concrete is made sufficiently stiff, but an interior and
perimeter trench for the footing makes the best foundation.
[0146] Place interior pads, if in-situ concrete is to be utilized
for them.
[0147] Set mobile home section(s) in place by conventional
trailering methods, and onto usual interior simple-supports by
conventional methods. If the interior pads are soil-contact
treated-wood, then they are set concurrently with the piers.
[0148] Make utility connections, if preferable to do so now.
[0149] Hang the foundation panels, all around the perimeter, or as
required by structural design. For the case where each panel
assembly 11 or 11' (of FIG. 1, 4, or 7) has the top strip 13, 30,
or 15 pre-attached, the panel assemblies will attach directly about
the perimeter nailer 28 (FIG. 4), or its equivalent. Typically
screws or small lag screws would be set through prepunched holes in
the top strip into the vertical face of nailer 28.
[0150] Panel installation begins at a strategic location, keeping
in mind that panels are installed in adjacent-contiguous sequence,
as each with a male seam-flange interlocks to the previous-adjacent
female seam (per conventional decking seam geometry). As explained
in the description section above, the male-female seam
shear-attachment is most easily accomplished with an adhesive. When
installed continuously about the unit, the last panel must usually
be cut to fit up to the edge of the first panel, and can then be
attached to it by any manner. When the panel attachment is not
continuous, terminal edges of panel can be reinforced with a
channel-column element. For access-door openings, a single panel
(with a top of cap 54, FIG. 2B) can be set below the pre-situated
structure enough to create the opening.
[0151] Building corners can be followed by simply vertically
saw-kerfing enough of a panel to bend at the corner location, and
cutting out enough of the top strip to allow the bend. Thus the
panels simply wrap around the corner and keep going. Alternatively,
the panels can be cut altogether and started again at the corner,
but a corner-reinforcing element should be added for this
practice.
[0152] It is possible that panels could be width-dimensioned to
suit particular buildings, so corner elements would accept each
adjacent panel coming into a corner, and so field cutting of the
panels could be avoided altogether.
[0153] Place rebar. A course of rebar is attached to panels, and
can be utilized for straightening the panels to a true plane (much
as the building itself does along the top) if necessary. The bar
can be wire-tied to the flute feet 48, or it can be set upon the
tab anchors 46 and tied where necessary. For the purposes of truing
panels, the rebar is best of about 16 mm (5/8'') diameter.
[0154] Another course of rebar can also be set on spacer-blocks in
the trenches, but this is not necessary to this design.
[0155] Place perimeter footing concrete, very preferably with a
pump. The concrete is most easily placed from the outside when a
plastisizing agent is added, adjusting the mix to create a standard
truncated-cone concrete slump-test at about 7'' (180 mm). Panels
are checked for plumb, and adjusted, if necessary, while the
concrete is still fluid.
[0156] Install any vents, if required over what may be built into
panels. These vent openings can be cut into the panels, or the vent
openings can be installed at the perimeter (floor framing) above
the panels.
[0157] Apply a protective finish to the exterior of panels, if
desired. At locations of penetrations or cuts exposing ungalvanized
edges of the panels, a zinc-rich paint can first be applied, and
any recesses resulting from the cuts be caulked flush. The adjacent
panel seams exposed to the exterior can be caulked, before or after
any tar treatment. Then one can apply a texture finish or
insulation and/or a cement-stucco, if desired.
[0158] Adjust site grades and backfill against panels as
appropriate.
[0159] Non-HUD code Modular homes differ from HUD mobile homes in
that they do not have a trailer-chassis built it. So generally a
significant portion of the structure weight must be supported along
the perimeter, and this weight must of course be considered in
panel top configuration and in panel thickness. Interior supports
(if any), perimeter panels, and concrete are optimally placed
concurrently while modular units are on temporary supports. This
could also be a two phased, interior to exterior, operation. The
single-concrete-placement method would typically be as follows:
[0160] (a) Prepare site per 1 above. Interior footings may not be
present or necessary. [0161] (b) Set modular unit(s) in place.
Support to level and true, and preferably at locations that do not
interfere with permanent support locations. [0162] (c) While units
are on temporary supports, install any interior supports to unit if
the hang-before-concrete-placement variety. [0163] (d) Make utility
connections, if preferable to do so now. [0164] (e) Hang panels per
above, considering how the panel design for this structure would
affect the installation. [0165] (f) Place rebar per above. [0166]
(g) Place footing concrete for interior and perimeter per above.
Panels are checked for plumb, and adjusted, if necessary, while the
concrete is still fluid. [0167] (h) Install any interior supports
that are the install-after-concrete-placement variety. [0168] (i)
Remove temporary supports. [0169] (j) Install any vents per above.
[0170] (k) Finish panels per above. [0171] (l) Backfill grades per
above.
[0172] Note that because panel attachment goes very quickly, it is
preferably closed-in simultaneously with, or after, any interior
concrete placement, for either mobile or modular structures. This
allows better access to the interior work, and tighter scheduling
possibilities. Removal of temporary support is aided by creating
larger-than-normal crawl space access opening(s) or by not
enclosing the entire perimeter with panels, if desired. Normal
minimum building code required crawl space access openings will
generally allow removal of temporary supporting elements,
however.
[0173] For site-built structures the panels attach to a
pre-situated (by any method) linear member such as a conventional
wood rim-joist, or they can attach to a pre-situated
planar-floor-assembly of any type. Where these attachments allow
easy access to each side of the panels for concrete placement, any
need to use concrete plastisizer is avoided, and it is more
practical to place the concrete without a pump, if desired. The
steps to take for installing panels of this embodiment are easily
determined from the description above.
[0174] This invention is independent of the method of geometry
definition for the structure or element that is holding the panels
in place. It is simply one that effectively exploits that geometry
presence for the construction of a foundation. Thus, the geometry
defining structure can be any object capable of being physically
pre-supported in its finished position, and benefits by having a
permanent foundation.
[0175] While most of the disclosure continuously mentions
"perimeter" in association with these foundation wall panels, they
can be used identically, or in different embodiments, as interior
foundation walls.
[0176] The design of these apparati and methods is made to be as
generally applicable as possible. This described method is possible
with an assortment of existing products put to new types of use.
For example, a panel of most any corrugation pattern will be able
to: make the same type of top connections; utilize the same
benefits of the diverging cuts along the bottom edge; and provide
ventilation via the flutes, if desired.
[0177] In so far as breadth of applications, here is yet another
example: These panels provide the most efficient means of placing a
retrofit perimeter foundation beneath an older home (which was
originally built upon now-inadequate piers). With the use of these
panels, the home does not have to be lifted up and set back down.
Concrete forms do not have to be set and stripped (or block-work is
omitted), so avoiding all that difficult work that must be done
with great difficulty in a cramped crawl space. Ponywalls do not
have to be built (and made to fit into tight, irregular spaces),
and then shear-sheathed.
[0178] With this new method of retrofit, the perimeter posts and
piers are shifted clear of the panel location (as must be done
anyway), then the panels are then simply attached and cast in
concrete, etc.
[0179] Of course the variations in panel connection and in
pre-situated member type can vary considerably from the operation
described herein, given the permutations resulting from various
panel embodiments and applications, all utilizing the same basic
principles and methods presented. Although the description above
contains many specificities, these should not be construed as
limiting the scope of the invention, but merely as providing
illustration of the preferred embodiments. The specifics shown
merely depict illustration of a few of the possible configurations
that utilize these cost-effective foundation panels beneficially.
Variations and adaptations of this new foundation construction
method will suggest themselves to a practitioner of the
construction method and material arts. For example, the deformation
pattern examples shown here can easily be varied considerably, or
omitted altogether where load conditions allow.
[0180] It must be stressed that the present invention is
independent of the physical guide, which is required to be
pre-situated for the attachment and collocation of these structural
panels. A few examples of that guide are given, but it can be just
about anything structurally capable.
[0181] The preferred embodiment of the invention is described above
in the Drawings and Description of Preferred Embodiments. While
these descriptions directly describe the above embodiments, it is
understood that those skilled in the art may conceive modifications
and/or variations to the specific embodiments shown and described
herein. Any such modifications or variations that fall within the
purview of this description are intended to be included therein as
well. Unless specifically noted, it is the intention of the
inventor that the words and phrases in the specification and claims
be given the ordinary and accustomed meanings to those of ordinary
skill in the applicable art(s). The foregoing description of a
preferred embodiment and best mode of the invention known to the
applicant at the time of filing the application has been presented
and is intended for the purposes of illustration and description.
It is not intended to be exhaustive or to limit the invention to
the precise form disclosed, and many modifications and variations
are possible in the light of the above teachings. The embodiment
was chosen and described in order to best explain the principles of
the invention and its practical application and to enable others
skilled in the art to best utilize the invention in various
embodiments and with various modifications as are suited to the
particular use contemplated.
* * * * *