U.S. patent application number 12/437092 was filed with the patent office on 2010-11-11 for method for building wind turbine tower.
Invention is credited to George L. Southworth.
Application Number | 20100281818 12/437092 |
Document ID | / |
Family ID | 43050839 |
Filed Date | 2010-11-11 |
United States Patent
Application |
20100281818 |
Kind Code |
A1 |
Southworth; George L. |
November 11, 2010 |
METHOD FOR BUILDING WIND TURBINE TOWER
Abstract
A method for erecting a tower includes the steps of providing a
first pre-cast section of concrete and positioning it atop a
foundation. A radially-inwardly extending ledge is attached to an
interior wall of the first pre-cast section and a plurality of
jacks is positioned below the ledge in circumferentially spaced
apart relation to one another. The ledge and the first pre-cast
section are raised to a first height by operating jacks in an
ascending mode. A second pre-cast section is positioned beneath the
first pre-cast section after the first pre-cast section has been
lifted to the first height. The first pre-cast section is lowered
onto the second pre-cast section by operating the jacks in a
descending mode or the second pre-cast section is lifted by
operating the jacks in ascending mode. An assembly building that
surrounds a base of the tower protects workers from inclement
weather.
Inventors: |
Southworth; George L.;
(Tampa, FL) |
Correspondence
Address: |
SMITH HOPEN, PA
180 PINE AVENUE NORTH
OLDSMAR
FL
34677
US
|
Family ID: |
43050839 |
Appl. No.: |
12/437092 |
Filed: |
May 7, 2009 |
Current U.S.
Class: |
52/745.17 |
Current CPC
Class: |
E02D 35/00 20130101;
E02D 27/42 20130101; E04H 12/34 20130101; F05B 2240/912 20130101;
E02D 27/425 20130101 |
Class at
Publication: |
52/745.17 |
International
Class: |
E04G 21/14 20060101
E04G021/14; E04B 1/19 20060101 E04B001/19 |
Claims
1. A method for erecting a tower formed of multiple sections,
comprising the steps of: providing a foundation for supporting said
tower; providing a first section and positioning said first section
atop said foundation; securing at least one radially-inwardly
extending ledge member to an interior wall of said first section;
positioning a jack means below said at least one radially-inwardly
extending ledge member; lifting said at least one radially-inwardly
extending ledge member and hence said first section to a first
predetermined height by operating said jack means in an ascending
mode; and positioning a second section beneath said first section
after said first section has been lifted to said first
predetermined height, said first predetermined height being
substantially equal to a height of said second section and a
predetermined clearance space.
2. The method of claim 1, further comprising the steps of: lowering
said first section onto said second section by operating said first
plurality of jack means in a descending mode.
3. The method of claim 2, further comprising the steps of: securing
a trailing end of said first section to a leading end of said
second section.
4. The method of claim 3, further comprising the steps of: securing
at least one radially-inwardly extending ledge member to an
interior wall of said second section; positioning said first
plurality of jack means below each of said at least one
radially-inwardly extending ledge member so that the jack means of
said first plurality of jack means are circumferentially spaced
apart from one another; lifting said at least one radially-inwardly
extending ledge member and hence said second section to said first
predetermined height by operating said first plurality of jack
means in an ascending mode; and positioning a third section beneath
said second section after said second section has been lifted to
said first predetermined height.
5. The method of claim 1, further comprising the steps of: forming
a trench having a predetermined extent in said foundation;
providing a cart adapted to shuttle along said extent between an
outer end and an inner end of said trench; said cart adapted to
carry a sub-section of a section from said outer end of said trench
toward said inner end so that said sub-section does not contact a
top surface of said foundation when said sub-section is in
transport; said cart adapted to lower said subsection so that said
sub-section is supported by said foundation and not said cart when
said sub-section is delivered by said cart to a position from which
said sub-section is to be elevated.
6. The method of claim 5, further comprising the steps of: said
cart having a platform that is raised when said cart carries said
sub-section to said position from which said sub-section is to be
elevated; said platform of said cart being lowered below a plane
defined by said top surface of said foundation after said cart
delivers said sub-section to said position from which said
sub-section is to be elevated.
7. The method of claim 1, further comprising the steps of: forming
a cavity in said foundation; positioning a vertically-movable
platform in said cavity, said platform having a fully retracted
position where a top surface of said platform is flush with a top
surface of said foundation; lifting said second section into
abutting relation with said first section by elevating said
platform; connecting said first and second sections to one another
while said platform is elevated; and lowering said platform after
said step of connecting said first and second sections to one
another is accomplished.
8. The method of claim 1, further comprising the steps of: forming
a plurality of cavities in said foundation; providing a second
plurality of jack means; positioning a jack means of said second
plurality of jack means into at least some of the cavities of said
plurality of cavities; lifting said second section into abutting
relation to said first section by operating said second plurality
of jack means in an ascending mode.
9. The method of claim 8, further comprising the steps of: securing
a trailing end of said first section to a leading end of said
second section.
10. The method of claim 9, further comprising the steps of:
securing a radially-inwardly extending ledge member to an interior
wall of said second section; positioning said first plurality of
jack means below said radially-inwardly extending ledge member so
that the jack means of said first plurality of jack means are
circumferentially spaced apart from one another; lifting said
radially-inwardly extending ledge member and hence said second
section to said first predetermined height by operating said second
plurality of jack means in an ascending mode; and positioning a
third section beneath said second section after said second section
has been lifted to said first predetermined height.
11. The method of claim 1, further comprising the steps of:
providing said first plurality of jack means in the form of
climbing jacks having steel poles; arranging said circumferentially
spaced apart climbing jacks in equidistantly spaced relation to one
another; positioning a first brace member between at least two
opposed steel poles.
12. The method of claim 11, further comprising the steps of:
positioning said first brace member at a predetermined height
within the hollow interior of said first section so that said brace
member does not interfere with movements of workers within said
hollow interior of said second section when said first section is
elevated to a height sufficient to provide clearance for said
second section.
13. A method for erecting a tower, comprising the steps of:
providing a foundation for supporting said tower; providing a first
section and positioning said first section atop said foundation;
lifting said first section to a first predetermined height;
providing a vehicle adapted to carry a second section from a remote
location onto said foundation and aligning said second section with
said first section; mounting a plurality of jack means in said
vehicle; lifting said second section into abutting relation to said
first section by operating said jack means in an ascending mode;
securing said first and second sections to one another; and
lowering said jack means after said first and second sections are
secured to one another.
14. A method for erecting a tower, comprising the steps of:
providing a foundation for supporting said tower; providing a
plurality of cavities in said foundation; positioning a jack means
in at least one of said cavities so that a lifting surface of said
jack means is substantially flush with a top surface of said
foundation when said jack means is fully retracted; providing a
first section and positioning said first section atop said
foundation; lifting said first section to a first predetermined
height; providing a vehicle adapted to carry a second section from
a remote location onto said foundation and aligning said second
section with said first section; forming at least one opening in
said vehicle such that said at least one opening is aligned with
said at least one jack means when said second section is aligned
with said first section; lifting said second section into abutting
relation to said first section by operating said jack means in an
ascending mode; securing said first and second sections to one
another; and fully retracting said jack means after said first and
second sections have been secured to one another.
15. A method for erecting a tower of multiple sections, comprising
the steps of: providing a foundation for supporting said tower;
positioning a lift plug atop said foundation; assembling a first
section of said tower around said lift plug; lifting said lift plug
and hence said first section to a first elevation, said first
elevation being substantially equal to a vertical distance equal to
a height of a section of said tower and a clearance distance;
positioning a second section directly below said first section;
lifting said second section into abutting relation to said first
section; and securing a leading end of said second section to a
trailing end of said first section.
16. A method for erecting a tower that includes multiple sections,
comprising the steps of: providing a foundation for supporting said
tower; positioning a lift plug atop said foundation; assembling a
first section of said tower around said lift plug; lifting said
lift plug and hence said first section to a first predetermined
height, said first predetermined height being substantially equal
to a vertical distance equal to a height of a section of said tower
and a clearance distance; positioning a second section directly
below said first section; bringing said first and second sections
into abutting relation to one another; and securing a leading end
of said second section to a trailing end of said first section.
17. The method of claim 16, further comprising the steps of:
bringing said first and second sections into abutting relation to
one another by lowering said first section onto said second
section.
18. The method of claim 17, further comprising the steps of:
bringing said first and second sections into abutting relation to
one another by lifting said second section into abutting relation
to said first section.
19. The method of claim 1, further comprising the steps of:
erecting an assembly building that surrounds a base of said tower
to protect workers from inclement weather; providing an opening in
a roof of said assembly building to accommodate erection of said
tower.
20. The method of claim 1, further comprising the steps of:
embedding respective first ends of a plurality of vertically
oriented rebars in said second section so that respective second
ends of said rebars extend from a top horizontal end wall of said
second section; and forming a plurality of mating sockets in a
horizontal bottom end wall of said first section so that said
respective second ends of said vertically oriented rebars are
received within said respective sockets when said first section
surmounts said second section.
21. The method of claim 1, further comprising the steps of:
embedding respective first ends of a plurality of vertically
oriented rebars in said first section so that respective second
ends of said rebars extend from a bottom horizontal end wall of
said first section; and forming a plurality of mating sockets in a
horizontal top end wall of said second section so that said
respective second ends of said vertically oriented rebars are
received within said respective sockets when said first section
surmounts said second section.
22. The method of claim 1, further comprising the steps of:
positioning a turbine in surmounting relation to said first section
prior to the step of lifting said first section to said first
predetermined height.
23. The method of claim 1, further comprising the step of: forming
at least one of the sections of said tower of concrete.
24. The method of claim 1, further comprising the step of: forming
at least one of the sections of said tower of pre-cast
concrete.
25. The method of claim 1, further comprising the step of: forming
at least one of the sections of said tower of a non-cementitious
material.
26. The method of claim 1, further comprising the step of: forming
at least one of the sections of said tower of steel.
Description
FIELD OF THE INVENTION
[0001] This invention relates, generally, to methods for erecting
tall structures. More particularly, it relates to a method for
building a tower that supports a wind turbine.
DESCRIPTION OF THE PRIOR ART
[0002] Wind turbines are very heavy and they operate best at high
elevations. They are usually mounted atop steel or concrete towers
that are not stayed by guy wires. Both types of towers are
typically built from the ground up.
[0003] One problem with conventional building techniques is that
workers must expose themselves to greater and greater heights as
tower construction progresses. This problem is exacerbated if the
work has to be performed in inclement weather.
[0004] Many sites that are ideal for wind turbine farms are in
northern climes where winds are strong and temperatures are low for
much of the year. When conditions deteriorate to unacceptable
levels, work on such towers in the field must be stopped.
Construction companies spend the winter months shipping in parts,
materials, supplies, and making plans for the construction season.
A burst of construction activity than takes place when the weather
warms until the work is forced indoors again.
[0005] Conventional wind turbine towers are typically constructed
from the ground up. The turbine must therefore be lifted to a great
height and attached to the top of the tower as the last step in the
tower-construction process. Due to the extreme weight of a wind
turbine nacelle, the lifting must be performed under very low wind
conditions. Accordingly, lengthy delays can be experienced at the
very end of the tower-building process.
[0006] There is a need, then, for an improved construction method
for such towers. The improved method would not expose workers to
dangerous heights nor would it expose workers to inclement weather.
The improved method would also enable towers to be built throughout
the year with no winter, poor weather, or high-winds
interruptions.
[0007] There is a need as well for a tower construction method that
includes mounting the turbine to the top section of the tower while
the top section is at ground level so that the turbine-lifting and
securing process can be performed at any time of the year and
without waiting for very low wind conditions.
[0008] However, in view of the prior art taken as a whole at the
time the present invention was made, it was not obvious to those of
ordinary skill how the identified needs could be fulfilled.
SUMMARY OF THE INVENTION
[0009] The long-standing but heretofore unfulfilled need for an
improved method for erecting wind turbine towers is now met by a
new, useful, and non-obvious invention.
[0010] The inventive method for erecting a tower includes the steps
of providing a first pre-cast section of concrete having a
generally tubular construction and positioning the first pre-cast
section at ground level on a previously constructed foundation
capable of supporting great weights such as twenty-five hundred
tons. The first pre-cast section may be a monolithic section having
a hollow, cylindrical shape or a hollow, tapered cylindrical shape
where its diameter at its lower end exceeds its diameter at its
upper end. The first pre-cast section may also be formed of
independently formed arcuate parts that collectively form a
pre-cast section when assembled and secured to one another.
[0011] The longitudinal axis of the pre-cast section is normal to
the weight-bearing foundation. A radially-inwardly extending ledge
member, or "haunch," is detachably secured to an interior wall of
the first pre-cast section and at least one jack is positioned
below the radially-inwardly extending haunch in circumferentially
spaced apart relation to one another if more than one (1) jack is
employed so that operating the jacks in an ascending mode raises
the ledge member and therefore the first pre-cast section.
[0012] A second pre-cast section of concrete is positioned directly
below the first pre-cast section after the first pre-cast section
is lifted to a first predetermined height. In a first embodiment,
the first pre-cast section is then lowered onto the second pre-cast
section by operating the jacks in a descending mode.
[0013] In a second embodiment, the jacks maintain the first section
at its first predetermined height and hydraulic or other suitable
means are used to lift the second pre-cast section into engagement
with the elevated first pre-cast section. This avoids the
surrendering of elevation and the subsequent re-gaining of said
elevation required by the first embodiment, i.e., the second
embodiments avoids operating the jacks in the descending mode when
the jacks are under load.
[0014] The hydraulic means of the second embodiment includes a
plurality of hydraulic cylinders positioned below a platform that
is vertically movable in relation to the weight-bearing foundation.
When fully retracted, the platform is disposed in a cavity formed
in the foundation and the top surface of the platform is flush with
the top surface of the foundation. The distance over which such
hydraulic cylinders must operate is substantially equal to a
clearance distance between the bottom or trailing end of the first
pre-cast concrete section and the top or leading end of the second
pre-cast concrete section that is positioned beneath the first
section when said first section has been elevated to its first
predetermined height. When fully extended, the platform lifts the
second section so that the clearance space is closed, i.e., so that
the top of the second section abuts the bottom of the first
section. The platform remains elevated until the first and second
sections have been secured to one another. It then returns to its
fully retracted position of repose and its cycle is repeated for
each individual pre-cast section until the tower is completed.
[0015] In the first embodiment, the jacks are lowered to their
initial, lowermost position after the first section has been
lowered onto the second section and said sections have been secured
to one another. All materials that need to cure are substantially
cured before any further lifting is performed.
[0016] In the second embodiment, the jacks are lowered to their
initial, lowermost position while the hydraulic cylinders continue
to support the platform in its elevated position and hence the
first and second sections in their respective elevated positions.
The haunches are then placed onto the second section and the jacks
are lifted to support said haunches and hence said first and second
sections. The hydraulic cylinders are then retracted back into
their position of repose, thereby returning the platform to its
fully retracted position where its top surface is flush with the
top surface of the weight-bearing foundation. The cavity that
receives the platform has the same depth as the height dimension of
the platform so that when the platform is in its fully retracted
position of repose, it is flush with the foundation.
[0017] In a third embodiment, the movable platform is eliminated.
Instead, a plurality of jacks are positioned in cavities formed in
the foundation The jacks are aligned with the pre-cast concrete
sections and lift them directly as needed to close the clearance
space between an elevated pre-cast section and the pre-cast section
disposed directly below it on the foundation.
[0018] In a fourth embodiment, the pre-cast sections are off-loaded
at the assembly building from a railroad car onto a wheeled cart
and the wheeled cart or other such vehicle positions the pre-cast
section directly below an elevated section. For example, in an
embodiment where a pre-cast section has three (3) parts that are
assembled to create the section, then three (3) carts would be
employed.
[0019] In a first variation of the fourth embodiment, each cart is
equipped with jacks to lift its load upwardly until the lower
pre-cast section abuts the elevated one, i.e., until the clearance
space is eliminated.
[0020] In a second variation of the fourth embodiment, jacks in the
foundation lift the load from the carts.
[0021] In all embodiments, the radially-inwardly extending haunches
may be detached from the first pre-cast section and attached to the
second pre-cast section after the first and second sections are
disposed in abutting end-to-end relation to one another and after
said first and second sections have been joined together at said
abutting ends. However, the haunches may also be provided with
clearance spaces through which the jacks may travel so that the
haunches need not be detached. The jacks are then operated in their
ascending mode to lift the first and second pre-cast sections to a
predetermined height sufficient to enable insertion of a third
pre-cast section below the second pre-cast section, in the first
embodiment, the jacks are again operated in their descending mode
to lower the first and second pre-cast sections in surmounting
relation to the third section. In the second embodiment, the
hydraulic cylinders are again operated to lift the platform so that
the top or leading end of the third section enters into abutting
relation to the bottom or trailing end of the second section.
[0022] The tower is completed by repeating the same steps for as
many sections of pre-cast concrete as needed. The jacks are
preferably equidistantly spaced apart from one another so that they
share a common load. They are operated slowly in both their
ascending and descending modes and they are operated so that each
jack performs lifting and lowering at a rate in common with the
other jacks.
[0023] The climbing jacks may or may not be used in a fifth
embodiment. A frusto-conical lift plug having the same shape and
size as the hollow interior of the top section of the tower is
snugly inserted into said hollow interior of said top section of
the tower when said top section is at ground level. As in the first
two embodiments, the wind turbine is preferably placed into
surmounting relation to the first section before said first section
is elevated. However, it is within the scope of this invention that
the nacelle not be lifted into its operable position until the
tower is completed. The lift plug and hence the first section with
the turbine there atop are hydraulically lifted to a first
elevation as in the first two embodiments to provide clearance for
the second section. After the second section is in place directly
under said elevated first section, the elevated first section may
be lowered as in the first embodiment or the second section may be
lifted into mating engagement with the first, elevated section as
disclosed in connection with the second, third, or fourth
embodiments. The two sections are interconnected in the same way as
in the first two embodiments. That procedure is repeated until the
tower is completed.
[0024] Guy wires are preferably used during construction of the
tower. They are preferably mounted on computer-controlled reels so
that they remain taught at all times, whether the tower is rising
or descending as in the first embodiment or rising only as in the
other embodiments.
[0025] The novel method also includes the steps of erecting an
assembly building that surrounds a base of the tower to protect
workers, parts, equipment, and materials from inclement weather and
temperature extremes. An opening in a roof of the assembly building
is provided to accommodate erection of the tower and closure means
for said opening may be provided. The assembly building provides a
controlled environment not just for worker comfort but also so that
multiple materials may be used even if outdoor conditions would
prevent their use. For example, welding is problematic in extreme
cold, as is concrete pouring and curing. With a controlled
environment within the confines of the assembly building, many
routine construction procedures that are interrupted by inclement
weather can continue without interruption throughout the year.
[0026] The assembly building also has utility in enhancing the
stability of the tower in the same way that a boss helps stabilize
an upstanding post. The assembly building has further utility in
connection with the deployment of guy wires.
[0027] Construction details include the step of embedding
respective first ends of a plurality of vertically oriented rebars
in the second pre-cast section so that respective second ends of
said rebars extend from a top or leading horizontal end wall of the
second pre-cast section. A plurality of mating sockets is formed in
a horizontal bottom or trailing end wall of the first pre-cast
section so that the respective second ends of the vertically
oriented rebars are received within the respective sockets when the
first pre-cast section surmounts the second pre-cast section. The
first section of the tower is the only section that does not
require rebars protruding from its top horizontal end wall unless
such rebars are useful in securing a turbine to said top horizontal
end wall. The final, bottom section of the tower is the only tower
section that does not require sockets formed in its bottom or
trailing horizontal end wall.
[0028] The connecting structure just disclosed could also be
reversed, i.e., the rebars could extend downwardly from the upper
section and the rebar-receiving sockets could be formed in the
lower section. The invention is not limited to any particular
connection. The abutting ends of contiguous sections could be
welded, bolted, or otherwise connected to one another.
Post-tensioned connections could also be used.
[0029] For towers that are relatively short in height, each
pre-cast section can be formed in tubular form, i.e., as a
monolithic unit, with each section except the top section having
upwardly extending rebars protruding from its horizontal top end
wall and each section except the bottom section having sockets
formed in its horizontal bottom end wall.
[0030] For larger towers, some or all of the pre-cast sections may
be too large to transport to the construction site if manufactured
in tubular, monolithic form. It may be practical, however, to
manufacture two (2) pre-cast sections, each of which forms a
semicircle, and to transport such semicircular sections to the
construction site. Very tall towers may require three (3) or more
pre-cast sections to make one (1) tubular section when the three
(3) or more sections are assembled together. Short towers can also
be manufactured in easily-transportable sub-sections that are
assembled at a construction site into the generally tubular form of
a tower section.
[0031] When a tubular pre-cast section is to be assembled from two
(2) or more arcuate sub-sections, the sub-sections are joined to
one another much like the tubular sections are joined to one
another when vertically stacked. More particularly, a first
vertical edge of each arcuate sub-section is provided with at least
one rebar having a first end embedded within the pre-cast arcuate
sub-section so that a second end protrudes in a horizontal plane
from said vertical edge. A second vertical edge of each arcuate
sub-section is provided with at least one horizontally disposed
mating socket for accommodating a rebar projecting from a
contiguous sub-section. All rebar/socket connections, whether on
the top and bottom horizontal end walls or on the vertical side
walls of a pre-cast section, are filled with grout, epoxy, or the
like after the rebars and sockets are fully coupled to one another
and the grout or epoxy is allowed to substantially cure before a
pre-cast tubular section is lifted to make room for the next
pre-cast section. The parts may also be joined together by welding,
various mechanical couplings, and so on. This invention is not
limited to any particular fastening or coupling means.
[0032] Alternatively, the sub-sections may be bolted or welded to
one another along their abutting vertical edges, or by other
suitable connections, such as post-tensioned connections, just as
the abutting horizontal ends of the respective sections may be
joined to one another.
[0033] The preferred jacks used in the first two embodiments are
climbing jacks of the type that climb steel poles. Each steel pole
is positioned radially inwardly of the radially-inwardly extending
ledge or haunch member that is attached to each pre-cast section.
The steel poles are braced with reinforcing poles or other bracing
means that may be positioned radially inwardly of the steel poles
in parallel or other supporting relation thereto. The reinforcing
poles are braced with horizontally disposed braces that
interconnect opposed reinforcing poles. The braces are positioned
at a predetermined height so that they do not interfere with
movement of workers within the hollow interior of the pre-cast
section that is at ground level.
[0034] Although this disclosure is primarily based upon an
all-concrete tower, it is important to note that not every section
need be formed of concrete. For example, the weight of the tower
can be reduced by making one or more sections out of a
non-cementitous material such as steel. The first section of the
tower, i.e., the one surmounted by the nacelle, could be formed of
steel, for example. The second section could also be formed of
steel, and so on. Any percentage of the tower may be formed of
materials other than concrete. It is therefore understood that this
invention is not limited in scope to all-concrete towers.
[0035] An important object of this invention is to enable
construction of tall wind turbine towers, or towers for other
purposes, without requiring construction workers to climb to unsafe
heights.
[0036] Another important object is to disclose a construction
procedure whereby a turbine weighing three hundred fifty to five
hundred tons or more is elevated to the top of a tower while the
top section of the tower is supported by a ground level foundation
so that the heavy weight is erected at an elevation where wind is
not as large a factor as when lifting a turbine to the top of a
conventional tower after the tower has reached its maximum
height.
[0037] Another important object is to enable construction workers
to erect a tall tower while the workers and parts, equipment,
materials and the like are protected from inclement weather and
temperature extremes by an assembly building.
[0038] An object closely related to the preceding object is to
provide a construction method that can follow a predetermined
schedule without regard to weather conditions so that such towers
can be installed on a dependable time schedule.
[0039] Another object is to provide a tower made from concrete or
other suitable materials so that the tower is very stable and can
resist high winds.
[0040] Yet another object is to provide a tower made from modular
parts so that the modular parts can be made on or off site in a
controlled manufacturing environment and transported to a
construction site for assembly in a controlled manufacturing
environment.
[0041] Another important object is to employ guy wires to stabilize
the tower as its height increases.
[0042] An object closely related to the foregoing object is to
provide guy wires that are mounted on computer-controlled reels so
that the guy wires remain taut during all phases of the
construction process, including upward and downward travel of the
pre-cast sections if the first embodiment is used and including
upward travel only if the other embodiments are used.
[0043] These and other important objects, advantages, and features
of the invention will become clear as this description
proceeds.
[0044] The invention accordingly comprises the features of
construction, combination of elements, and arrangement of parts
that will be exemplified in the description set forth hereinafter
and the scope of the invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0045] For a fuller understanding of the nature and objects of the
invention, reference should be made to the following detailed
description, taken in connection with the accompanying drawings, in
which:
[0046] FIG. 1A is a side elevational view of the novel assembly
shop and a tower near the beginning of the construction
process;
[0047] FIG. 1B is a side elevational view of the novel assembly
shop and the tower after completion of about a fourth of the
construction process;
[0048] FIG. 1C is a top plan view of the structures depicted in
FIGS. 1A and 1B;
[0049] FIG. 1D is a side elevational view of the novel assembly
shop and the tower after completion of about half of the
construction process;
[0050] FIG. 1E is a side elevational view of the novel assembly
shop and the tower after completion of about three-fourths of the
construction process;
[0051] FIG. 1F is a side elevational view of the novel assembly
shop and a tower after completion of the construction process;
[0052] FIG. 2A is a top plan view of three (3) pre-cast concrete
parts having a common height and a common curvature prior to their
attachment to one another;
[0053] FIG. 2B is a top plan view like that of FIG. 2A, depicting
said three (3) pre-cast concrete parts in their assembled
configuration;
[0054] FIG. 3A is a perspective view of a pre-cast concrete
section, depicting a radially-inwardly extending ledge or haunch
detachably secured thereto;
[0055] FIG. 3B is an exploded perspective view of the pre-cast
concrete section depicted in FIG. 3A;
[0056] FIG. 4A is a sectional view depicting a climbing jack
disposed beneath a ledge or haunch prior to lifting of a first
pre-cast concrete section;
[0057] FIG. 4B is a sectional view depicting the first pre-cast
section when lifted about half way to its maximum elevation;
[0058] FIG. 4C is a sectional view depicting the first pre-cast
concrete section in its fully elevated position;
[0059] FIG. 4D is a sectional view depicting a second pre-cast
concrete section that has been placed into position beneath the
first pre-cast concrete section and depicting the clearance space
between the trailing end of the top section and the leading end of
the bottom section;
[0060] FIG. 4E is a sectional view depicting the first pre-cast
concrete section when it has been lowered into surmounting relation
to the second pre-cast concrete section;
[0061] FIG. 5A is a sectional view in five (5) animations depicting
the use of a cart in a trench to carry the sub-sections from a
delivery station to the assembly station;
[0062] FIG. 5B is the second view of said five views;
[0063] FIG. 5C is the third view of said five views;
[0064] FIG. 5D is the fourth view of said five views;
[0065] FIG. 5E is the fifth view of said five views;
[0066] FIG. 6A is a side elevational sectional view of the second
embodiment depicting the first tower section in its first elevated
position and depicting the clearance space between the trailing end
of the top section and the leading end of the bottom section and
depicting the platform of the second embodiment in its fully
retracted position;
[0067] FIG. 6B is a side elevational sectional view depicting the
second tower section positioned in abutting relation to said first
tower section and depicting the platform in its fully elevated
position;
[0068] FIG. 6C is a side elevational sectional view like that of
FIG. 5B but depicting the installation of the haunches when the
climbing jacks are returned to their respective lowermost
positions;
[0069] FIG. 6D is a side elevational sectional view depicting the
climbing jacks at their respective uppermost positions to provide
clearance for the next pre-cast section to be moved into position
under the elevated section;
[0070] FIG. 7A is the first side elevational view of an animation
of four views depicting the lifting of a sub-section into abutting
relation to a previously elevated section to close a clearance gap
between the two sections;
[0071] FIG. 7B is the second view in said animation;
[0072] FIG. 7C is the third view in said animation;
[0073] FIG. 7D is the fourth view in said animation;
[0074] FIG. 8A is the first side elevational view of an animation
of three views depicting use of a cart in lifting a sub-section
into abutting relation to a previously elevated sub-section to
close a clearance gap between the two sections;
[0075] FIG. 8B is the second view in said animation;
[0076] FIG. 8C is the third view in said animation;
[0077] FIG. 9A is the first side elevational view of an animation
of three views depicting the use of a cart in lifting a sub-section
into abutting relation to a previously elevated section to close a
clearance gap between the two sections;
[0078] FIG. 9B is the second view in said animation;
[0079] FIG. 9C is the third view in said animation;
[0080] FIG. 10A is a perspective view of a wheeled vehicle carrying
no load and positioned near the position of the wheeled vehicle
depicted in FIG. 9A;
[0081] FIG. 10B is a perspective view of a wheeled vehicle carrying
no load and positioned near the position of the wheeled vehicle
depicted in FIGS. 9B and 9C;
[0082] FIG. 10C is a perspective view of a wheeled vehicle carrying
a load and positioned near the position of the wheeled vehicle
depicted in FIG. 9A;
[0083] FIG. 11 is a top plan view depicting the braces that support
the steel poles of the climbing jacks;
[0084] FIG. 12A is the first side elevational, diagrammatic view in
a series of seven views that animate the steps of a third
embodiment, up to the assembly of the first three sections of the
novel tower;
[0085] FIG. 12B is the second view in said series of seven
views;
[0086] FIG. 12C is the third view in said series;
[0087] FIG. 12D is the fourth view in said series;
[0088] FIG. 12E is the fifth view in said series;
[0089] FIG. 12F is the sixth view in said series;
[0090] FIG. 12G is the seventh view in said series;
[0091] FIG. 13 is a cross-sectional view taken along line 13-13 in
FIG. 12G;
[0092] FIG. 14 is a side elevational view of a completed third
embodiment tower prior to retraction of the lift plug;
[0093] FIG. 15 is a diagrammatic view depicting subterranean access
into the hollow interior of the tower; and
[0094] FIG. 16 is a perspective view of a completed tower with a
nacelle wind turbine in surmounting relation to the tower.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0095] Referring now to FIGS. 1A-F, it will there be seen that an
illustrative embodiment of the invention is denoted as a whole by
the reference numeral 10.
[0096] Structure 10 includes wind turbine 12 that surmounts first
section 14a of tower 14. The first section, and any other section,
may be made of pre-cast concrete, concrete prepared at the site, or
a non-cementitious material such as steel. Assembly building 16 at
the base of the tower protects the workers, parts, materials,
supplies and equipment used to erect the tower from the elements
and temperature extremes during construction. It can be taken down
and moved to a new construction site when the work is completed or
it can be left in place to provide shelter. Guy wires 18a, 18b are
conventional and radiate outwardly in at least three directions as
depicted in the plan view of FIG. 1C. This invention includes a
novel method for guy wire usage as the tower is erected as best
indicated by the arrows in FIGS. 1D and 1E. More particularly,
since the guy wires must remain taut as the tower sections are
elevated, the unreeling of the guy wires from their respective
reels must be coordinated with the lifting motion of the jacks. In
the first embodiment, where the tower is lowered a small distance
with each new section, the reeling in of the guy wires must be
coordinated with the lowering motion. The coordination of reeling
guy wires in or out at a rate to match the lifting or lowering rate
of the jacks is preferably computer-controlled.
[0097] The blades connected to wind turbine 12 are not depicted to
simplify the drawing. The blades and turbine 12 are not a part of
the invention per se.
[0098] Tower 14 is formed of multiple sections which are referred
to primarily as pre-cast concrete sections for convenience, with
the understanding that the invention is not limited to pre-cast
concrete sections as aforesaid. In the depicted example, the
sections are denoted 14a-h. This invention is not limited to any
particular number, size or shape of sections. For example, the
pre-cast sections could form a generally triangular structure in
horizontal cross-section where three (3) straight sides of a
triangle are interconnected by arcuate corners or where three (3)
arcuate sides of a triangle include straight sections at each
end.
[0099] Tower 14 is hollow and each section is therefore generally
tubular in configuration in a preferred embodiment of the
invention. The tower is preferably tapered to have a diameter that
gradually reduces with height. Each pre-cast section therefore has
a diameter at its top or leading end that is less than its diameter
at its lowermost or trailing end. Towers that are not tapered are
also within the scope of this invention. However, if a tower has a
uniform diameter from top to bottom, the turbine that surmounts the
tower must be cantilevered to a greater extent than is required
with a tapered tower because the blades must not strike the tower.
The increased overhang of the turbine relative to its support as
required by an untapered tower increases the stresses on the
structure. Moreover, an untapered tower could be much heavier than
a tapered tower.
[0100] FIGS. 2A and 2B are top plan views depicting how each
section 14 is assembled inside building 16. In this particular
embodiment, three (3) railroad tracks 11a, 11b, and 11c are
positioned in equidistantly, circumferentially spaced relation to
one another so that first section 14a may be assembled from three
(3) arcuate sub-sections 1, 2, 3, each of which is small and light
enough to be transported over public highways or railways to the
construction site. Depending upon the application, the sub-sections
could be reduced to only two (2) semicircular parts or the number
of sub-sections could be greater than three (3). A pre-cast
concrete section having a diameter sufficiently small so as not to
require assembly is also within the scope of this invention. For
example, the top section of a tower may have a diameter
sufficiently small to avoid any need for making said top section in
sub-sections, and the same may be true for other highly elevated
sections.
[0101] As depicted in FIG. 2A, a first vertical end wall of each
arcuate part has recess or socket 19a formed therein and a second
vertical end wall has rebar 19b formed therein. The confronting
rebars and recesses thus mate with one another when sub-sections 1,
2, and 3 are displaced radially inwardly from their respective FIG.
2A positions to their respective FIG. 2B positions. Grout or other
bonding material is then introduced into each recess and allowed to
cure to create a solid joint. In this way, each pre-cast section of
tower 14 when fully assembled has a structural integrity
substantially similar to what it would be if the section were
integrally formed. The tower is never lifted nor lowered until all
connections are completely finished and all materials that need to
cure have been cured to the required strength. The
climate-controlled assembly building facilitates the making of all
connections and the curing of all materials because said
connections and curing processes are made within said building.
[0102] Section 14a, the section at the top of the tower, is the
first section assembled. Turbine 12 is placed atop said section by
any suitable means, including a conventional crane, after the grout
has cured. This is an important feature of the invention because it
eliminates the dangerous and difficult prior art practice of
lifting the turbine to the top of the tower as the final step in
the tower construction process.
[0103] As depicted in FIGS. 3A and 3B, each arcuate pre-cast
sub-section includes a pair of radially-inwardly extending ledges
or haunches 15. Each haunch 15 may be formed of pre-cast concrete,
steel, or other strong material. For reasons that will become clear
as this disclosure continues, each haunch may be integrally formed
with its pre-cast sub-section or it may be detachably secured to
its associated sub-section. When the haunches are to be detachably
secured, a bore or socket, denoted 15a is formed in each pre-cast
sub-section on their respective radially inwardly facing surfaces
as depicted in FIG. 3B and a corresponding number of plugs in the
form of protruding rebars, collectively denoted 15b, are formed in
the respective radially outwardly facing surfaces of each haunch as
also depicted in FIG. 3B. The haunches are much lighter in weight
than the sub-sections to which they are attached so the plugs are
inserted into the sockets by any feasible means. No grout is added
in applications where the plugs are disengaged from their
associated sockets after each section lifting operation is
performed. The climbing jacks are returned to their respective
lowermost positions after each sub-section is lifted to a height
that allows a subsequent sub-section to be positioned beneath it.
Where the haunches are integrally formed with their respective
pre-cast concrete sections, a passageway is formed in them so that
the climbing jacks may pass through such passageway, thereby
eliminating the need to remove the haunches after each lift.
[0104] Referring now to FIGS. 4A-4E, it will be understood in
connection with those Figs. that a conventional crane, such as a
traveling crane, is preferably used to lift the nacelle to the top
of the first pre-cast concrete section at the beginning of the
construction process. However, placing the nacelle atop a completed
tower near the end of the construction process is also within the
scope of this invention.
[0105] As best understood in connection with FIGS. 4A-E and FIGS.
5A-E, each climbing jack 20 requires a vertical steel pole 22 to
climb. Each jack includes a first pair of upper opposed plates and
a second pair of lower opposed plates; said first and second pairs
of opposed plates are vertically spaced apart from one another.
When the upper plates converge toward one another to engage the
steel pole, the lower plates diverge away from one another so as
not to engage said steel pole. When the upper plates tightly engage
the steel pole, the vertical distance between the upper opposed
plates and the lower opposed plate is reduced, i.e., the lower
opposed plates travel upwardly under hydraulic power to a point on
the steel pole directly under the upper opposed plates. The lower
plates then tightly engage the steel pole. After the steel pole is
fully engaged by the lower plates, the upper plates release their
grip on the steel pole and the upper plates are raised under
hydraulic power until they are a predetermined distance above the
lower plates. Upon reaching said predetermined distance, the upper
plates again engage the steel pole. After said upper plates have
fully engaged the steel pole, the lower plates release their grip
on said steel pole and the above-recited steps are repeated. The
tower is lifted when the upper plates are raised; they engage the
bottom surface of their respective haunches.
[0106] The climbing jacks and their associated steel poles are
positioned radially inwardly of the pre-cast concrete sub-sections.
When each climbing jack is in its fully lowered position, as
depicted in FIG. 4A, uppermost end 20a of each climbing jack is at
an elevation slightly lower than an underside of each haunch or
ledge 15. Climbing jacks 20 are hydraulically powered and operate
in synchronization with each other and with the guy cables so that
each pre-cast concrete section is held level as it is lifted. When
section 14a (turbine 12 being omitted to simplify the drawing)
attains a height greater than the combined height of section 14b of
tower 14 and the needed clearance space, the sub-sections of
section 14b, of which there are three in this particular example,
are brought together and secured to one another in the manner
recited above. The climbing jacks then climb down their respective
steel poles at a common rate of descent, gently lowering the
turbine atop said assembled section 14a. The climbing jacks
continue climbing down their respective steel poles until they
reach their respective initial position of repose as depicted in
FIG. 4A as aforesaid.
[0107] More particularly, FIG. 4B depicts section 14a after it has
been lifted a short distance and FIG. 4C depicts section 14a after
it has been lifted to a height sufficient to receive section 14b
beneath it. FIG. 4D depicts section 14b after it has been moved
into position beneath said section 14a and FIG. 4E depicts section
14a after it has been lowered into surmounting relation to section
14b.
[0108] Each pre-cast sub-section 1, 2, 3 has a plurality of rebars,
collectively denoted 13a, extending from its uppermost horizontal
end wall and a corresponding number of rebar-receiving sockets,
collectively denoted 13b, formed in its lowermost horizontal end
wall.
[0109] After section 14a has been lifted and section 14b moved into
place beneath it, and after said section 14a has been lowered into
surmounting relation to said section 14b as aforesaid,
radially-extending haunches 15 are then detachably secured to their
respective arcuate sub-sections 1, 2, 3. The radially innermost
edge of each haunch when connected to its associated arcuate part,
is radially outwardly of each steel pole 22. The lifting surface of
each climbing jack is positioned below its associated haunch. Thus,
as climbing jacks 20 ascend their associated steel poles 22 at a
common rate of ascent, their associated haunches 15 and hence
sub-sections 1, 2, and 3 are thereby lifted.
[0110] The climbing jacks are operated until the bottom or trailing
of section 14a is positioned above the floor of building 16 by a
distance equal to the height of section 14b, including the height
of rebars 13a projecting upwardly therefrom, and a further
preselected clearance distance to ensure that said bottom of
section 14a will not interfere with the interlocking of
sub-sections 1, 2, and 3 of section 14b when said section 14b is
assembled in the same manner as section 14a. When section 14b is
fully assembled and the grout or other bonding material around the
rebars has substantially cured, the climbing jacks are lowered so
that rebars 13a projecting upwardly from section 14b enter into
their associated sockets 13b formed in the bottom end wall of
section 14a as section 14a is lowered into overlying relation to
section 14b.
[0111] Haunches 15 are then removed from section 14a and said
haunches are lowered so that they can be detachably secured to
section 14b.
[0112] This process is repeated for the remaining sections. Only
one (1) set of ledges or haunches is needed.
[0113] However, if haunches 15 are formed integrally with their
respective pre-cast sections, the climbing jacks travel through a
clearance space or passageway formed in the haunches to enable the
climbing jacks to descend without being blocked by the
haunches.
[0114] FIGS. 4A-E do not depict a means for bringing second section
14b from its FIG. 4C position to its FIG. 4D position.
Theoretically, if friction forces are not too high, the
sub-sections resting atop the support surface could simply be
pushed or pulled by any means until they converge with one another
and line up underneath elevated first sub-section 14a.
[0115] FIGS. 5A-5E depict an embodiment where the support surface
of the tower is a thick concrete pad or platform 32. A trench or
ditch 32a is formed in concrete platform 32 and a cart, preferably
supported by railroad tracks, is adapted to travel in said ditch.
Each cart 17a includes a platform 30 that can be hydraulically
lifted and lowered. A pre-cast sub-section of the tower is taken
from a railroad car and deposited atop platform 30 when platform 30
is slightly elevated as depicted in FIG. 5A. The depth of the ditch
or trench and the height of the cart are predetermined so that when
the cart travels away from the railroad car to the position of FIG.
5B, the bottom edge of the pre-cast section will clear the top
surface of platform 32 by a short distance. This moves the
sub-section to its FIG. 5B position without sliding said
sub-section atop platform 32. When cart 17a attains its FIG. 5B
position, platform 30 is hydraulically lowered until the
sub-section is supported by platform 32. This removes the load from
platform 30 of cart 17a and enables the cart to return on its
tracks to the station where it receives its next load. Cart 17a
therefore never carries more than the weight of one sub-section and
platform 32 carries the load of the tower as it is lowered to make
each connection between the sub-sections.
[0116] FIGS. 6A-D depict a second embodiment of the invention. This
embodiment eliminates the need to lower the tower to join the
horizontal trailing wall of an upper section to the horizontal
leading wall of its contiguous lower section.
[0117] As depicted in FIG. 6A, hydraulic cylinders 30 are mounted
in thick concrete foundation 32 that overlies ground 34. Concrete
platform 36 is mounted within a cavity formed in foundation 32 so
that the top surface of said platform is flush with the top surface
of foundation 32 when platform 36 is in its fully retracted
position as depicted in FIG. 6A. In FIG. 6A, first section 14a has
been elevated by the climbing jacks and second section 14b has been
positioned directly below said first section. Accordingly, there is
a clearance space between the bottom of section 14a and the top of
section 14b.
[0118] Activation of a hydraulic motor or motors causes cylinders
30 to rise upwardly to lift platform 36 and second section 14b to
their respective positions depicted in FIG. 6B. This closes the
clearance space and sections 14a and 14b are then connected to one
another by the various connections means disclosed above, or any
other suitable connection means. With the full weight of the tower
supported by hydraulically-lifted platform 36, a control signal
sent to the climbing jacks enables them to climb downwardly from
their respective elevated FIG. 6A positions to their respective
lowered FIG. 6B positions.
[0119] Haunches 15 are then installed onto section 14b as depicted
in FIG. 6C and another control signal again activates the climbing
jacks to lift pre-cast section 14b a distance to enable the next
pre-cast section or sub-sections to be positioned under it as
depicted in FIG. 6D. With the full weight of the tower bearing upon
the climbing jacks, platform retracts 36 to its initial position of
repose, flush with foundation 32, to enable said next pre-cast
section or sub-sections to be moved into place as depicted in said
FIG. 6D.
[0120] Due to the weight of the tower, it is desirable to reinforce
each steel pole 22. As depicted in FIGS. 5A-E and FIG. 6A-D, one
way of doing that is to position a second reinforcing steel pole 23
radially inwardly of each climbing jack steel pole 22 and to
interconnect said poles to one another at vertically spaced
intervals as at 25. Plural braces, denoted 27a-d, are then
positioned in horizontally-disposed, bracing relation to opposed
steel poles 23 as depicted. Braces 27a are positioned about seven
feet (7') above the floor of building 16 so as not to interfere
with movement of workers in the building. At least one additional
set of braces may also be provided above the first set of
braces.
[0121] FIGS. 7A-D depict a third embodiment where movable platform
36 is eliminated. Hydraulic jacks 30 are positioned within cavities
30a formed within concrete foundation 32 so that their respective
lifting surfaces are flush with the top surface of foundation 32
when the jacks are fully retracted as depicted in FIGS. 7A and 7D.
As depicted in FIG. 7B, a pre-cast section is lifted by a distance
sufficient to close the clearance gap between the bottom edge of an
elevated pre-cast concrete section and a top edge of a pre-cast
section supported by said foundation. After the upper edge of the
lower section has been bonded or otherwise coupled to the lower
edge of the upper section, jacks 30 are then retracted and the
process continues as before. FIG. 7C depicts the attachment of a
haunch while a jack means 30 is extended but the jacks may also be
employed in haunch-less embodiments.
[0122] FIGS. 8A-C depict a fourth embodiment. Each pre-cast section
or sub-section is transferred from a railroad car or other delivery
vehicle to a wheeled cart 17a or other suitable vehicle and the
cart or carts travel a short distance from the delivery vehicle to
the tower erection site as depicted in FIG. 8A. Carts 17a are
preferably self-propelled but may be pushed or pulled. Each cart
17a travels to a position where the concrete section or sub-section
it carries is aligned directly below the elevated section as
depicted in FIG. 8B. Hydraulic jacks 30 are built-in to each cart
and when activated lift the section or sub-section upwardly into
abutting relation to the elevated section as depicted in FIG.
8C.
[0123] FIGS. 9A-C depict a variation of the fourth embodiment.
Instead of jacks 30 being built-into the carts, said jacks 30 are
mounted in concrete foundation 32, just as in the third embodiment.
They extend through openings formed in cart 17a and lift the load
as needed, holding the section or sub-section in place until the
lifted section is secured to the elevated section.
[0124] FIG. 10A depicts a cart 17a in a position similar to the
position of FIG. 9A, but when carrying no load. FIG. 10B depicts a
cart 17a in a position similar to the position of FIGS. 9B and 9C,
but when carrying no load. FIG. 10C depicts a cart 17a in a
position similar to the position of FIG. 9A, and when carrying a
load.
[0125] The carts could be much wider than the carts that are
depicted so as to provide a more stable support for the concrete
sections or subsections. Moreover, additional jacks could be
provided in flanking relation to the depicted jacks, whether or not
the carts are provided in a wider form.
[0126] FIG. 11 is a top plan view depicting six (6) climbing jacks
20 and therefore six (6) steel poles 22, six (6) reinforcing steel
poles 23 and three (3) sets of diametrically extending braces 27.
The number and spacing of said jacks and poles is changed for
differing applications, it being understood that the number of
jacks and associated steel poles may increase as the height and
weigh of the pre-cast concrete tower increases.
[0127] The lifting of section 14a to accommodate section 14b
therebeneath lifts the bottom end wall of said section 14a above
the roof of building 16, or nearly so, depending upon the selected
height of building 16 and the overall height of section 14b. Due to
the relatively short extent of the combined heights of sections 14a
and 14b, guy wires may not be required as depicted to help secure
said section 14a against swaying. However, guy wires will be
required as the tower increases in height.
[0128] A fifth embodiment is depicted in FIGS. 12A-G, 13 and 14.
Wind turbine 12 and assembly building 16 are deleted from these
Figs. to simplify them.
[0129] As depicted in FIG. 12A, frusto-conical lift plug 40 having
the same shape and size as the hollow interior of top section 14a
of the tower is centered on platform 36 and the sub-sections of
section 14a are installed around it and secured to one another.
Accordingly, lift plug 40 is snugly received within the hollow
interior of top section 14a when said top section is at ground
level. The turbine is not depicted to simplify the drawing but said
turbine is lifted and deposited atop section 14a after said first
section has been assembled but before said first section is
elevated.
[0130] Lift plug 40 and hence first section 14a with the turbine
thereatop are hydraulically lifted to a first elevation as in the
first two embodiments to provide clearance for second section 14b
as best understood in connection with FIG. 11B. Hydraulic shaft 42
is centered within the interior of lift plug 40 and is driven
upwardly by a hydraulic motor, not depicted. Platform 36 remains in
its fully retracted position as depicted in FIG. 11B or said
platform is eliminated as in the third and fourth embodiments.
[0131] Hydraulic shaft 42 could be provided in relatively short
sections so that it would not need to extend downwardly into the
earth as drawn. A new section of shaft could be positioned directly
under an elevated shaft by a revolving mechanism such as provided
in revolver-type pistols, for example. The revolving mechanism
would rotate atop concrete foundation 32 and its chambers would be
re-loaded as needed. The ends of the shaft sections would be
coupled together by any suitable means to collectively form shaft
42. Such short sections could also be positioned in alignment with
main shaft 42 and connected thereto in many ordinary ways. They
could be carried into position by carts, they could be slid atop
foundation 32 while in an upright configuration, they could be
rolled to the center of the structure and then stood up to enter
into alignment with the main shaft, and so on.
[0132] In FIG. 12C, the sub-sections of second section 14b have
been displaced radially inwardly into their assembled configuration
directly below elevated section 14a. The elevation of first tower
section 14a is such that a clearance space is provided between
sections 14a and 14b, just as in the first two embodiments.
[0133] After second section 14b is in place directly under said
elevated first section 14a, foundation 36 is raised by hydraulic
cylinders 30 as in the second embodiment and as depicted in FIG.
12D to lift second section 14b into mating engagement with first
section 14a and the two sections are interconnected in the same way
as in the first two embodiments. Said elevation of second section
14b eliminates the clearance space depicted in FIG. 12C.
[0134] Hydraulic cylinders 30 then retract and platform 36 is
lowered to its position of repose as depicted in FIG. 12E.
[0135] As depicted in FIG. 11F, hydraulic cylinder or shaft 42 is
then extended further so that second section 14b attains an
elevation sufficient to move the sub-sections of tower section 14c
into position directly below section 14b.
[0136] Hydraulic cylinders 30 then lift section 14c into mating
engagement with section 14b by elevating platform 36 as depicted in
FIG. 12G.
[0137] The procedure depicted in FIGS. 12A-G is repeated until the
tower is completed. Lift plug 40 is retracted from the hollow
interior of first section 14a and lowered into overlying relation
to platform 36 to conclude tower construction.
[0138] FIG. 13 is a transverse sectional view of section 14b as
indicated in FIG. 12G.
[0139] FIG. 15 diagrammatically depicts subterranean tunnel 44 that
provides ingress and egress into and out of the hollow interior of
tower 14. Where a center shaft such as hydraulic cylinder 42 is
used, the entrance to the tunnel would not be centered in the
building as depicted. A centered entrance is suitable for the
embodiments that employ climbing jacks.
[0140] A completed tower having eight (8) sections, each made of
three (3) sub-sections, surmounted by nacelle 12, is depicted in
FIG. 16.
[0141] Building 16 protects all participants in the
tower-construction project from inclement weather, and the novel
method eliminates the need for any worker to be exposed to heights.
This enables tower construction to continue unabated in inclement
weather. The use of guy wires also enables tower construction to
continue even in relatively high wind conditions. Building 16 also
provides a temperature-controlled environment that enables the
making of connections that include grout, epoxy, or other
temperature-sensitive materials. These features enable a tower to
be raised much faster than a tower built by conventional from
bottom to top methods. The use of pre-cast concrete sections and
the novel from top to bottom method speeds the process even more,
thereby significantly reducing labor and other costs associated
with building pre-cast towers.
[0142] The use of multiple climbing jacks that are reinforced as
disclosed herein enables the building of pre-cast concrete towers
that may exceed three hundred feet in height and which may have
weights in excess of two thousand (2000) tons. The lift plug
embodiment can do the same but it is disclosed primarily to
indicate that the invention is not limited to the use of climbing
jacks.
[0143] It will thus be seen that the objects set forth above, and
those made apparent from the foregoing description, are efficiently
attained and since certain changes may be made in the above
construction without departing from the scope of the invention, it
is intended that all matters contained in the foregoing description
or shown in the accompanying drawings shall be interpreted as
illustrative and not in a limiting sense.
[0144] It is also to be understood that the following claims are
intended to cover all of the generic and specific features of the
invention herein described, and all statements of the scope of the
invention that, as a matter of language, might be said to fall
therebetween.
* * * * *