U.S. patent application number 13/537872 was filed with the patent office on 2013-08-08 for floatable constructions.
The applicant listed for this patent is Carl Richard Nelson. Invention is credited to Carl Richard Nelson.
Application Number | 20130199113 13/537872 |
Document ID | / |
Family ID | 45896572 |
Filed Date | 2013-08-08 |
United States Patent
Application |
20130199113 |
Kind Code |
A1 |
Nelson; Carl Richard |
August 8, 2013 |
Floatable Constructions
Abstract
A plurality of floatable constructions are provided, the
constructions including a floating base for a building, the base
having at least one buoyant basement unit defining a basement
level, and a reinforced concrete transfer platform atop the
basement unit. The basement level can provide habitable or
functional space for the building, and the transfer platform has at
least one access opening giving access to the basement level which
is enhanced by windows for light and ventilation. Methods and means
of tying modular components of the structures together, and
materials suitable for manufacturing such ties, are also
provided.
Inventors: |
Nelson; Carl Richard;
(Reading, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nelson; Carl Richard |
Reading |
|
GB |
|
|
Family ID: |
45896572 |
Appl. No.: |
13/537872 |
Filed: |
June 29, 2012 |
Current U.S.
Class: |
52/169.1 ;
52/741.15 |
Current CPC
Class: |
B63B 2035/4426 20130101;
Y02A 30/00 20180101; E04H 9/145 20130101; E02D 27/06 20130101; B63B
35/44 20130101; Y02A 50/00 20180101 |
Class at
Publication: |
52/169.1 ;
52/741.15 |
International
Class: |
B63B 35/44 20060101
B63B035/44; E04H 9/14 20060101 E04H009/14 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 2, 2012 |
GB |
1201877.6 |
Claims
1. A construction for supporting a building, comprising: a pit
excavated below ground level; a buoyant basement unit within the
pit, comprising an upper load-bearing surface for supporting a
building; and guide means for substantially preventing lateral
movement of the basement unit and allowing vertical movement of the
basement unit, wherein: the pit is larger in plan view than the
basement unit so that when the basement unit is not floating a
recess surrounds the basement unit within the pit; and the
construction comprises an external floor extending substantially
across the recess.
2. The construction of claim 1, wherein the external floor is
formed integrally with the basement unit.
3. The construction of claim 1, wherein when the basement unit is
not floating the external floor is flush with ground level.
4. The construction of claim 1, wherein when the basement unit is
not floating the gap between the external floor and the edge of the
pit is not more than 75 mm.
5. The construction of claim 4, wherein a grill extends across the
gap.
6. The construction of claim 1, wherein the external floor
comprises a buoyant material encased in concrete.
7. The construction of claim 6, wherein the buoyant material is
polystyrene.
8. The construction of claim 1, wherein the external floor forms a
walkway surrounding a majority of the basement unit.
9. The construction of claim 1, wherein the buoyant basement unit
provides at least one habitable room.
10. The construction of claim 1, wherein the basement unit extends
above the external floor.
11. The construction of claim 1, wherein the basement unit has
windows above the external floor for light and/or ventilation.
12. The construction of claim 1, wherein the basement unit is
formed from fibre reinforced concrete.
13. The construction of claim 1, wherein the basement unit
comprises outer walls and a floor, which together with the upper
load-bearing surface form a continuous structure.
14. The construction of claim 1, wherein the basement unit further
comprises internal walls forming therein a plurality of habitable
rooms.
15. The construction of claim 1, wherein: the basement unit
comprises outer walls and a floor; and the upper load-bearing
surface comprises a transfer platform supported by the outer
walls.
16. The construction of claim 1, wherein the upper load-bearing
surface comprises reinforced concrete encapsulating an array of
voids.
17. The construction of claim 1, wherein the upper load-bearing
surface is fire resistant.
18. The construction of claim 1, wherein the pit is supported by a
plurality of sheet piles.
19. The construction of claim 1, wherein the pit is supported by
walls formed of a plurality of bricks.
20. The construction of claim 1, wherein the floor of the pit is
formed of concrete.
21. The construction of claim 1, wherein the guide means comprise
piles extending into the floor of the pit and sliders or rollers
fixed to the basement unit.
22. The construction of claim 21, wherein the piles are hollow and
act as a conduit for heat extracted from the ground.
23. The construction of claim 1, further comprising on the upper
load-bearing surface a building having a plurality of rooms.
24. The construction of claim 1, further comprising a bridge
arranged to movably extend from the ground to the building or the
external floor over a range of heights of the basement unit.
25. The construction of claim 1, further comprising a barrier
extending downwardly from the distal edge of the external floor,
the barrier arranged to allow the passage of water
therethrough.
26. A method of providing a construction that can float, comprising
the steps of: excavating a pit below ground level; locating a
buoyant basement unit within the pit; providing guide means to
substantially prevent lateral movement of the basement unit; and
providing an external floor extending substantially across the
recess, wherein the pit is larger in plan view than the basement
unit so that when the basement unit is not floating a recess
surrounds the basement unit within the pit.
27. The method of claim 26, wherein the external floor is formed
integrally with the basement unit.
28. The method of claim 26, wherein when the basement unit is not
floating the external floor is flush with ground level.
29. The method of claim 26, wherein when the basement unit is not
floating the gap between the external floor and the edge of the pit
is not more than 75 mm.
30. The method of claim 26, further comprising providing a grill
extending across the gap.
31. The method of claim 26, further comprising encasing a buoyant
material in concrete to form the external floor.
32. The method of claim 31, wherein the buoyant material is
polystyrene.
33. The method of claim 26, wherein the external floor forms a
walkway surrounding a majority of the basement unit.
34. The method of claim 26, wherein the buoyant basement unit
provides at least one habitable room.
35. The method of claim 26, wherein the basement unit extends above
the external floor.
36. The method of claim 26, wherein the basement unit has windows
above the external floor for light and/or ventilation.
37. The method of claim 26, further comprising forming the basement
unit from fibre reinforced concrete.
38. The method of claim 26, wherein the basement unit comprises
outer walls and a floor, which together with the upper load-bearing
surface form a continuous structure.
39. The method of claim 26, wherein the basement unit further
comprises internal walls forming therein a plurality of habitable
rooms.
40. The method of claim 26, wherein: the basement unit comprises
outer walls and a floor and the method further comprises supporting
a transfer platform upon the outer walls.
41. The method of claim 26, wherein the upper load-bearing surface
comprises reinforced concrete encapsulating an array of voids.
42. The method of claim 26, wherein the upper load-bearing surface
is fire resistant.
43. The method of claim 26, further comprising providing a
plurality of sheet piles to support the walls of the pit.
44. The method of claim 26, further comprising providing a
plurality of bricks to support the walls of the pit.
45. The method of claim 26, further comprising forming a layer of
concrete to provide the floor of the pit.
46. The method of claim 26, wherein the guide means comprise piles
extending into the floor of the pit and sliders or rollers fixed to
the basement unit.
47. The method of claim 26, wherein the piles are hollow and act as
a conduit for heat extracted from the ground.
48. The method of claim 26, wherein the basement unit comprises an
upper load-bearing surface on which a building having a plurality
of rooms is provided.
49. The method of claim 26, further comprising providing a bridge
arranged to movably extend from the ground to the building or the
external floor over a range of heights of the basement unit.
50. The method of claim 26, further comprising providing a barrier
extending downwardly from the distal edge of the external floor,
the barrier arranged to allow the passage of water
therethrough.
51. A construction for supporting a structure, comprising: a pit
excavated below ground level; a buoyant basement unit within the
pit, comprising an upper load-bearing surface for supporting a
structure, wherein: the basement unit is arranged to move between a
non-floating position in which the basement unit is supported by a
floor of the pit, and a floating position in which the basement
unit is supported by a threshold amount of water within the
pit.
52. The construction of claim 51, wherein the threshold amount of
water is less than an amount of water required to fill the pit.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Pursuant to 35 U.S.C. 119(a), the instant application claims
priority to prior United Kingdom application number GB 1201877.6,
filed Feb. 2, 2012.
FIELD OF THE INVENTION
[0002] The present invention relates to constructions that are
normally at rest on the ground or some form of solid support, but
can float during periods of flooding. In particular, but not
exclusively, the invention relates to constructions having a
buoyant basement structure which support conventional
buildings.
BACKGROUND OF THE INVENTION
[0003] In modern urban environments, the development and
construction of large buildings for residential, commercial,
leisure or industrial use can often be beset with problems.
[0004] For example, a site in UK may have been previously
developed, but with a change of legislation the land may now be
classified as within a flood zone, e.g. Planning Policy Statement
25 (PPS 25) & the Development and Flood Risk Practice Guide
dated June 2008. PPS25 is part of the holistic approach to managing
risk set out in the Government's strategy for flood and coastal
erosion management, Making Space for Water (Defra, 2005).
[0005] Flooding can cause substantial damage to property and
threaten human life, as the floods of 2007 in the UK showed. Such
damage is a consequence of previous decisions about location and
nature of settlement and land use.
[0006] Floating or floatable buildings, which are not based on
vessels, are known. For example, U.S. Pat. No. 6,199,502 describes
the use of connectable concrete flotation modules with polystyrene
cores to create a floating pontoon on which structures can be
supported. The flotation modules are designed to be transportable
by land vehicles, so that a large number of modules are required to
create a floating platform of modest size, and the weight that can
be supported by the platform is limited.
[0007] U.S. Pat. No. 5,647,693 describes a floatable building
having a watertight concrete basement of unitary construction which
provides buoyancy in the event that the site of the building is
flooded. As in a conventional building with a basement, the walls
of the basement structure support the floor joists and walls of the
building above. This limits design freedom and compromises access
to the basement. The basement is constructed at the site of the
building, and remains in place after construction until floodwater
raises the building.
SUMMARY OF THE INVENTION
[0008] According to a first aspect of the invention, there is
provided a construction defined by claim 1.
[0009] According to a second aspect of the invention, there is
provided a method of constructing a structure that can float
defined by claim 26.
[0010] According to a third aspect of the invention, there is
provided a construction defined by claim 51.
[0011] Such a construction preferably comprises a floating base for
a building, the base having at least one buoyant basement unit
defining a basement level, and a reinforced concrete transfer
platform atop the basement unit. The basement level can provide
habitable or functional space for the building, and the transfer
platform has at least one access opening giving access to the
basement level which is enhanced by windows for light and
ventilation.
[0012] The basement unit may be manufactured from 300 mm micro
fibre reinforced concrete. On the top of the wall sections ties may
be cast in to connect the walls to the transfer platform. In
embodiments in which the transfer platform is made of concrete, the
walls may comprise a plurality of ties, each tie extending partly
within the transfer platform. In such an embodiment, the ties may
be connected to the reinforcement of the transfer platform.
[0013] Preferably, the ties extend from the basement unit into the
transfer platform, so as to securely connect the transfer platform
to the basement unit. The ties may, for example, be cast into the
basement unit during construction of said unit, or may be bolted or
otherwise affixed to the basement unit.
[0014] Optionally, the ties may extend from the transfer platform
into the basement unit. In this case, the ties may be inserted into
holes drilled in one or more basement units, and the ties may be
retained in the holes by adhesive filler, such as a resin grout or
mortar.
[0015] Preferably, where a part of a tie extends within a basement
unit, that part of the tie is approximately 400 mm to 750 mm in
length. Preferably, the ties comprise reinforcing bars.
[0016] Preferably, additional starter bar ties may be cast into the
concrete wall sections to provide a means of attachment to a
walkway discussed in detail below.
[0017] The ties may, for example, be cast into the basement unit
during construction of said unit, or may be bolted or otherwise
affixed to the basement unit.
[0018] Preferably, the starter bar ties comprise reinforcing
bars.
[0019] The transfer platform preferably comprises a lightweight
reinforced concrete slab. For example, the transfer slab may
include an array of voids, optionally formed by an array of void
formers. Alternatively, the transfer platform may be formed of a
plurality of wooden joists, which are preferably secured to the
walls of the basement unit by galvanized straps. In this way, the
mass of the floating basement unit can be kept to a minimum, and
the centre of gravity can be low in the base so as to provide
stability to the base.
[0020] The upper surface of the transfer platform may include a
layer of tiles or timber floorboards to form a finished floor.
[0021] The construction comprises guide means for preventing
horizontal movement of the basement unit. The guide means may
comprise locating means which are fixed relative to the ground and
engagement means arranged to engage with the locating means. The
engagement means may, for example, comprise rollers arranged in
rolling contact with the locating means, or sliders arranged in
sliding contact with the locating means.
[0022] The locating means may comprise either timber or steel piles
set into the ground. Advantageously, steel hollow piles could house
apparatus for extracting heat from the ground for supply to the
building, such as ground source heating apparatus.
[0023] The basement units are preferably micro-fibre reinforced
concrete which, advantageously, is approximately 300 mm thick.
However, it is conceivable that the basement units could be formed
of other materials, such as steel.
[0024] Sheet steel piling (preferably corrugated) may form the
walls of the excavated pit.
[0025] A depth of 500 mm of water in the pit is preferably
sufficient to lift the basement unit through displacement
pressure.
[0026] Advantageously, the basement unit can provide a load-bearing
platform to support the weight of a superstructure thereon.
[0027] In preferred embodiments, the construction comprises a
floating basement unit in accordance with the first aspect of the
invention, and a superstructure upon the basement unit. A transfer
platform provides a load-bearing surface to distribute the weight
of the superstructure across the basement unit.
[0028] The basement unit having the transfer platform provides a
mechanically uniform platform upon which a superstructure of
substantially any design and construction can be built. In some
embodiments, the transfer platform may provide a driveway upon
which vehicles may be parked. The weight of the superstructure is
distributed across the base via the transfer platform, so there is
no need for correspondence between the position of the load-bearing
parts of the superstructure and the position of features within the
basement structure. Thus, the present invention offers a flexible
and adaptable way of constructing floating buildings.
[0029] As well as providing support for the superstructure, the
transfer platform can act as a fire barrier. Thus, if fire were to
break out in the basement level, unlike an open-framed load bearing
structure, the transfer platform would act to slow passage of fire
up into the superstructure. Consequently, the basement level can be
arranged to house plant for the building, such as equipment
associated with electricity generation, metering or distribution,
gas supply, water treatment, waste processing and so on.
DESCRIPTION OF THE DRAWINGS
[0030] The present invention will now be described, by way of
example only, with reference to the accompanying drawings, in
which:
[0031] FIG. 1 shows a cross-sectional view of a construction
forming a preferred embodiment of the present invention;
[0032] FIG. 2 shows a plan view of the construction of FIG. 1;
[0033] FIG. 3 shows a cross-sectional view of a walkway of the
construction of FIG. 1;
[0034] FIGS. 4a and 4b show the construction of FIG. 1 in two
positions;
[0035] FIG. 5 shows a cross-sectional view of a construction
forming a preferred embodiment of the invention in a first
position;
[0036] FIG. 6 shows a cross-sectional view of the construction of
FIG. 5 in a second position;
[0037] FIG. 7 shows a footbridge extending from ground level to a
superstructure in a preferred embodiment of a construction;
[0038] FIG. 8 shows a plan view of the construction of FIG. 7;
[0039] FIG. 9 shows a plan view of a locating pile; and
[0040] FIG. 10 shows a detailed cross-section of a transfer
platform.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0041] FIG. 1 shows a first embodiment of a construction
comprising: a pit 100; a buoyant basement unit 22; and a
superstructure 20 built upon the basement unit 22.
[0042] Preferably, the basement unit 22 comprises a floor and
external walls and one or more internal walls to define rooms in
the basement level. Optionally, the floor is generally rectangular
in plan, so that the rooms may be generally cuboidal.
[0043] Preferably, an external floor 33 extends from the basement
unit 22. Preferably, the external floor 33 is formed integrally
with the basement unit 22. The external floor 33 may be polystyrene
encased concrete, and can therefore act as an additional float.
Optionally, the external floor 33 substantially surrounds the top
of the basement. Thus, the external floor 33 can provide a walkway
to ensure that nobody can fall into the excavated pit in which the
basement unit 22 is located. Preferably, there is a gap of no more
than 75 mm between the edge of the external floor 33 and the pit
100 when the basement unit 22 is not floating. This can allow flood
water to cascade down into the pit 100.
[0044] The pit 100 is formed by digging below ground level 23 to a
depth sufficient to accommodate the majority of the buoyant
basement unit 22. The size of the pit 100 is greater than the size
of the basement unit so that a recess 24 will surround the basement
unit 22 when it is not floating. Preferably, the recess 24 will
have a width (i.e. the distance between the basement unit 22 and
the walls of the pit 100) of between 75 mm and 100 mm.
[0045] The pit 100 is preferably formed by excavating below ground
level 23, for example, in a flood plain area 23.
[0046] The buoyant basement unit 22 comprises outer walls 26 and a
floor. It can provide a floating base upon which the superstructure
20 is built or placed.
[0047] The basement unit 22 may comprise a transfer platform 25
which spans the entire basement unit 22. The transfer platform 25
may comprise a single unitary transfer slab, or a plurality of
joists (e.g. timber joists).
[0048] When a plurality of joists form the transfer platform 25,
these may abut each other to form a substantially continuous floor.
Alternatively, the joists may be provided with an additional
surface mounted thereon, such as a plurality of abutting floor
boards, to form a substantially continuous floor.
[0049] The bottom face of the transfer platform 25 rests upon and
is attached to the tops of the outer walls 26 of the basement unit
22. In this way, the transfer platform 25 may close the open top of
the basement unit 22.
[0050] The basement unit 22 may be a habitable space comprising one
or more rooms separated by internal walls. For the comfort of the
user, one or more windows 27 may be provided to provide light
and/or ventilation. Preferably, the depth of the pit 100 is chosen
such that the lower extent of the window(s) 27 is at ground level
when the basement unit 22 is not floating. In which case, the
basement unit may extend above the external floor by between 0.8 m
and 1 m.
[0051] The basement unit 22 may be formed of concrete in which is
cast reinforcing bars 44 (as can be seen in FIG. 3). Preferably,
the basement unit 22 is formed of fibre-reinforced concrete.
[0052] When a single unitary transfer platform 25 is used, this is
preferably formed as a lightweight reinforced concrete slab, for
example of the type marketed as BubbleDeck.RTM.. The slab 25
contains a plurality of voids, preferably defined by void formers
in the form of hollow plastic spheres, arrayed within a lattice of
reinforcing bars. The reinforcing bars and voids are set within a
concrete matrix.
[0053] The transfer platform 25 is preferably permanently attached
to the basement unit 22. The connections between the basement unit
22 and the transfer platform 25 may consist of reinforcing bars 44
which extend upwardly from the outer walls 26 of the basement unit
22 and into the transfer platform 25 (as can be seen in FIG.
3).
[0054] Furthermore, the transfer platform 25 may be formed of
concrete cast directly onto the top faces of the basement units 22
to form the connections. In this way, the transfer platform 25 and
the basement units 22 can be considered as a continuous reinforced
concrete basement structure.
[0055] The basement structure 22, and hence the building, may be
constrained from lateral movement by a number of locating piles 28.
Preferably, each locating pile 28 consists of a 300 mm steel column
pile, which is driven into the ground adjacent the basement
structure 22. At least one locating pile 28 is provided adjacent at
least two of the outer sides 26 of the basement structure 22.
[0056] Pile guides are attached to the outer surface of the
basement structure 22, just above the water line. Each pile guide
28 may comprise one or more rubberised rollers (not shown) mounted
on a galvanized steel frame. The frame of each pile guide extends
around one of the locating piles 28, and the rollers bear upon the
outer surface of the associated pile 28. In this way, the basement
structure 22, and the superstructure can rise or fall to
accommodate changes in the water level. However, lateral or
side-to-side motion of the basement structure 22 is prevented so
that the building remains in the desired position above its normal
resting place.
[0057] Within the basement structure 22, windows 27 can be position
at the top of the walls above ground level 23.
[0058] The basement unit 22 may be located on one or more
(preferably two) concrete spreader bars 31 which preferably have a
rectangular cross-section (preferably 500 mm deep.times.300 mm
wide) and a length sufficient to extend across the majority of the
basement unit 22.
[0059] These may be located on top of vertically oriented 300 mm
diameter piles 32, which are driven into the ground in the
conventional manner. The depth of these piles 32 may vary depending
on the weight of the structure.
[0060] Alternatively, a blinding layer of concrete 41 may be
provided on the ground.
[0061] In which case, the spreader bars 31 could be replaced small
blocks cast into the binding layer 41.
[0062] The spreader bars 31 or blocks (preferably formed of
concrete) can allow flood water to trickle underneath the basement
unit 22 to prevent a vacuum forming between the floor of the
basement unit 22 and the surface on which it rests.
[0063] The side walls 102 of the excavation can be kept in the
vertical position by the use of steel sheet piling 21 or by the use
of other materials such as pre-cast concrete planks or engineering
brickwork.
[0064] FIG. 3 shows a section of the external floor 33 around the
basement unit 22. Preferably, the external floor 33 comprises
fabric reinforcement 35 encased in concrete. The external floor 33
is preferably joined to the basement unit 22. This may be achieved
by the addition of splice reinforcing bars 34, which are attached
to the reinforcing bars 44 of the outer walls 26.
[0065] Most preferably, the external floor 33 encapsulates buoyant
float material 36, such as polystyrene, to thereby increase the
buoyancy of the basement unit 22.
[0066] In cross-section, the external floor 33 may be tapered from
its upper surface, which can provide a walkway.
[0067] The external floor 33 is preferably attached to the basement
unit 22 so that its upper surface is at ground level 23 to provide
a cover over the pit 100. The cover preferably does not necessarily
entirely close the pit 100 and there may be a gap around its
periphery to allow water to fill the pit 100. Additionally a grill
such as a metal grating can be placed over the remaining gaps
between the pit 100 and the external floor 33 for safety.
Preferably, the gap is not more than 75 mm.
[0068] The external floor 33 may continuously surround the basement
unit 22 or may be formed of one or more discrete sections separated
by gaps. In either case, the external floor covers a portion of the
recess 24 when the basement unit 22 is not floating.
[0069] Preferably, the upper surface of the external floor 33 is
flush with ground level 23.
[0070] The external floor 33 may be an integral part of the
basement unit 22.
[0071] The superstructure 20 can be pre-fabricated or manufactured
on the basement unit 22.
[0072] Renewable energy sources can be positioned on the roof of
the superstructure 20, such as solar photovoltaic panels and wind
turbines.
[0073] Whilst the description above has been directed to the use of
a single buoyant basement unit 22, the inventors have envisaged the
use of multiple buoyant basement units 22, connected together to
form a single floating structure. Preferably, the multiple basement
units 22 would have a single transfer platform 25 affixed thereon
and may together be substantially surrounded by an external floor
33.
[0074] It will be appreciated that the access ramps and other
connections between the ground and the basement unit 22, external
floor 33 and/or superstructure 20 are arranged to accommodate the
rising and falling motion of the building.
[0075] The superstructure is preferably a building having a
plurality of rooms (for example a house).
[0076] As can be seen from FIGS. 4a and 4b, when constructed as set
out above, the buoyant basement unit 22 may be movable between a
position in which it rests upon the floor of the pit (either
directly, or via supports 31) to a position in which it floats upon
a sufficient volume of water. The minimum volume of water suitable
for initial displacement of the mass of the basement unit 22 and
the superstructure 20 preferably corresponds to a depth in the
range of 0.5 m to 1 m within the recess 24.
[0077] As shown in FIG. 5, a second embodiment of a construction
may include access to the pit 100 via a manhole 40 (preferably, a
600 mm.times.600 mm manhole with a replaceable cover). A metal
ladder 41 between the floor of the pit 100 and the manhole 40 may
be provided. This allow for maintenance and the clearance of any
silt or debris which may accumulate in the pit 100.
[0078] Optionally, in either embodiment, a fence or handrail 60 is
attached around the walkway.
[0079] Preferably, a barrier 61 extends down into the pit 100 from
the basement unit 22 or, more preferably, from the outer edge of
the external floor 33. This may be secured in place by one or more
brackets 62 attached to the sheet piles 21.
[0080] Optionally, the barrier 61 may extend past the external
floor 33 to form the fence or hand rail 60.
[0081] FIG. 6 depicts the construction in a raised position when
the water level 50 has risen above ground level 23. In this
position, the barrier 61 can prevent debris from entering the pit
100.
[0082] The barrier 61 may be arranged to prevent the passage of
debris therethrough but allow the passage of water. The barrier 61
is preferably formed of a mesh or an apertured sheet. Preferably,
reinforcement is provided to maintain the shape of the barrier
61.
[0083] FIG. 7 shows an optional footbridge 70 extending from ground
level 23 around the pit 100 to the superstructure 20.
Alternatively, the footbridge 70 may span from ground level 23 to
the basement structure 22, or to the external floor 33.
[0084] Small metal ramps 73 may be provided at either end of the
footbridge 73 ensure ease of access for wheelchairs.
[0085] Optionally, a drive way may be provided to allow access for
vehicles to the basement unit 22 when it is not floating.
[0086] The footbridge 70 is free to pivot at either end to
compensate for movement of the construction. Preferably, at least
one end of the footbridge 70 is free to move laterally relative to
the ground 23 and/or the construction, to compensate for large
displacements of the construction. In preferred embodiments the end
of the footbridge 70 at the construction is free to pivot while the
other end of the footbridge 70 rests on rollers.
[0087] Preferably, the pivot at the construction end of the
footbridge 70 is mounted on the external floor 33, the transfer
platform 25, or the basement unit 22.
[0088] As can be seen from the plan view of FIG. 8, a driveway 74
for a vehicle may also be provided to span the pit 100. This would
have the same general construction as that set out above for the
footbridge 70.
[0089] A garage or porch 76 can be constructed adjacent to the
superstructure 20 for sheltering a vehicle and/or providing an area
for bin storage.
[0090] FIG. 9 shows a plan view of a preferable arrangement of
locating pile 28. As shown in the figure, the locating pile 28
stands outside the basement unit 22 and passes through an opening
in the external floor 33. At least one roller 80 is provided to
maintain the position of the locating pile 28 relative to the
opening. Preferably, a pair of rollers 80 are provided to retain
the locating pile 28 therebetween.
[0091] As shown in FIG. 9, the locating pile 28 may be an I-beam,
which provides channels in which rollers 80 may be provided.
[0092] Preferably, the rollers 80 comprise Teflon.
[0093] Optionally, the rollers 80 are attached to a metal bracket
83, which is attached to the external floor 33 using bolts 81.
[0094] FIG. 10 shows a detailed cross-section of the transfer
platform 25 to the wall of a preferred superstructure 20. In this
figure, the transfer platform 25 comprises a plurality of timber
joists 87, upon which a surface 86 (preferably formed of medium
density fibreboard) is provided. Surface 86 provides a continuous
surface on which a floor finish 85, such as floor boards or
carpeting, may be laid.
[0095] The joists 87 may abut or be spaced apart. When the joists
87 are spaced apart, an insulating material is preferably provided
therebetween.
[0096] Preferably a layer is provided upon the transfer platform 25
of a breather membrane (such as Tyvek DuPont.RTM. Airguard.RTM.
Control). Thus, an air and vapour tight base may be provided.
[0097] In preferred embodiments, the breathable membrane may extend
up a at least a portion of the walls of the superstructure 20.
[0098] The wall of the superstructure 20 may be formed of timber 83
on which a surface of acrylic render 86 is provided. A layer of
vapour check barrier and a layer of fibre board may be provided on
the inner surface.
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