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This invention relates to buildings. More particularly, this invention
relates to buildings of the type wherein a supporting tower is erected
first and floors are subsequently built at the base of the tower and
hoisted and fastened to the tower sides at their intended elevation to
complete the building.
SUMMARY OF THE PRIOR ART
It has been known to erect a supporting central tower or core and fabricate
around the base of the tower or core the floors of the building.
Subsequently, these floors of the building are raised -- the top floor
being raised first, and the bottom floor being raised last -- and
thereafter fastened to the tower.
In the past, such central towers have included their own floors with
openings to the peripheral floors. Thus the peripheral floors, when raised
and fastened, have to come into precise registry with the floors and
openings of the tower.
Moreover, the peripheral floors as fastened about the tower have heretofore
not contributed to the structural strength of the tower. Rather, they have
relied on the tower as an independent vertical structural member to
provide the full strength for the ultimate support of the building.
Further, the openings in the floor at the tower have constituted an
interruption in what would otherwise be the normal path for the placement
of floor stiffening and reinforcing horizontal and longitudinal beams. As
a result, expensive and elaborate paired and longitudinally extending
beams on either side of the tower -- preferably of steel -- have been
required by the prior art.
SUMMARY OF THE INVENTION
At least one hollow core tower (preferably of a rectangular construction)
is constructed from a foundation to a preselected floor supporting height.
The tower is preferably joined at the top and slotted vertically along at
least one sidewall from the base of the tower to a partial height of the
tower. Preferably the tower is slotted along opposed sidewalls to form
opposed C-shaped sections confronting one another at the slots. After at
least the lowest and ground adjacent portion of the tower is constructed,
floors are built about the tower at or near ground level. The floors
include a section extending into or across the tower at the slot or slots
which preferably includes a cantilevered or spanning horizontal floor
strengthening beam. Typically, the floors are constructed and stacked one
on another at their ground level with the bottom floor built first and
lowest, and the top floor or roof built last and highest at the top of the
ground supported stack. Floors with curtain walls preferably attached at
ground level are successively raised and fastened to the tower with the
top floor raised and fastened first, and the lower floor raised and
fastened last. With one or more of the floors in place, each floor at or
near its section adjacent the tower is fastened to the tower sides to
cross brace the tower at the slot. The floor section intimately surrounds
the tower and locks the opposed tower sections against outward deflecting
or dynamic movement. A bridge across the tower at each floor
simultaneously forms an interior lobby floor having on either side
building service shafts, such as those required for elevators, fire stairs
and conduits.
OBJECTS AND ADVANTAGES OF THE INVENTION
An object of this invention is to construct at ground level both a building
floor and a tower floor. According to this aspect, a hollow core tower is
provided with at least one vertically disposed slot extending from the
base of the tower to the supported height of a floor. The floor, as it is
constructed around the base of the tower, extends into and defines
interiorly of the tower at least a substantial portion of the tower floor.
When the peripheral floor is raised and fastened, the interior floor of
the tower is also raised and fastened providing simultaneously a floor
peripheral to the tower as well as a floor interior of the tower.
An advantage of this aspect of the invention is that the finished structure
of the central tower and the finished structure of the floor are the only
structures necessary to effect construction of the building. Supported
forms or supported partial braces to either the floor or the tower are not
required during construction.
A further advantage of this aspect of the invention is that registry of a
separate tower floor with a separate peripheral floor is not required.
A further object of this invention is to disclose a tower which has a
peripheral floor surrounding the tower with a section of the peripheral
floor bridging across the tower to support the tower floor. According to
this aspect of the invention at least one hollow core tower is slotted
preferably at opposed sidewalls from the base of the tower to at least the
floor supporting height of the tower. The peripheral floor is constructed
to extend into and span the tower at the slots. When the peripheral floor
is raised and fastened, the spanning floor is likewise raised and fastened
to provide a peripheral floor and tower floor simultaneously.
An advantage of this aspect of the invention is that the floor contributes
to the overall strength of the tower. Specifically, the floor as it is
fastened to the tower sidewalls cross braces the tower sidewalls at their
point of juxtaposition to the slot. Thus, as the floors are raised and
fastened, the tower is cross braced by the fastened floor.
Additionally, the peripheral floor surrounds the tower section which is
divided by the paired slots. Movement of one tower section away from the
other tower section under either static or dynamic loading is prevented. A
unitary self-bracing building structure results as the floors are fastened
in place.
A further advantage of the spanning floor at the tower is that the floor
extends in a natural building hallway disposition. Thus, where paired
towers are provided with slots opening along a common longitudinal axis of
a building, these aligned slots can define the natural path for a central
hallway in the building.
Yet another advantage of this aspect of the building is that the floors, as
bridging the tower, tend to naturally divide the tower to define within
the tower the necessary shafting for building services. For example, fire
stair shafts, elevator shafts, piping shafts and the like are all
naturally defined by the floor as it spans the slotted tower.
A further object of this invention is to provide in a peripheral floor a
natural path for a longitudinal floor stiffening and reinforcing beam.
According to this aspect of the invention, when the central tower is
constructed with opposed slots, a path for a floor stiffening beam
extending longitudinally of the floor and through the tower at the slot is
defined. By the expedient of placing the beam in the peripheral floor
along an axis coincident with the axis of the slot and raising and
fastening the floor to the tower, an improved floor construction results.
An advantage of this aspect of the invention is that the floor reinforcing
(consisting of a beam spanning the tower at the slot) is complementary to
the tower reinforcing (the fastening of the tower adjacent the slot to the
raised floor). Thus, the beam spanning the tower at the building top
serves the dual function of stiffening the floor as well as tying the
tower sections adjacent the slot one to another.
Another aspect of this invention is that the central beam of the floor is
defined overlying the hallway of underlying complementary floors. Since
heating, ventilating and air condition systems are commonly routed away
from hallways, a beam overlying a hallway can readily complement heating,
ventilating and air conditioning designs.
A further aspect of this invention is that a building constructed
symmetrically about its supporting towers results. High resistance to
dynamic building loadings is possible.
Other objects, features and advantages of this invention will become more
apparent after referring to the following specification and attached
drawings in which:
FIG. 1 is a perspective view of the building of the present invention in an
intermediate stage of construction with the floor slabs constructed but
not yet raised;
FIG. 2 is a plan view of one of the floor slabs of the present invention
illustrating the core towers in section;
FIG. 3 is a cross sectional view taken along lines 3--3 of FIG. 1;
FIG. 4 is a view similar to that of FIG. 3 with the beams in place and
illustrating one floor slab in phantom at its raised position;
FIG. 5 is a fragmentary side elevation view of the installation of a
curtain wall on one of the floor slabs;
FIG. 6 is a side elevation of one of the floor slabs containing a curtain
wall raised to its elevated position; and
FIG. 7 is a cross sectional view taken along lines 7--7 of FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An intermediate stage of construction of the building of the present
invention is illustrated in FIG. 1. At this stage, a pair of core towers
10, 12 has been constructed preferably by conventional reinforced concrete
slip forming techniques. A stack of reinforced concrete floor slabs 15-20
has been constructed at and around the base of the respective towers.
These floors 15-20 are formed with the lowest floor formed first and the
upper floor formed last. It should be noted that each floor as formed
serves as a support for the mold of an immediately overlying floor when it
is formed.
As depicted in the broken away portion of tower 12, each tower comprises a
pair of opposed C-shaped sections 22, 23, preferably joined at the top by
tower roof 24. Each C-shaped section 22, 23 is comprised of three
contiguous sidewalls which meet at right angles so that the two C-shaped
sections in combination have a generally rectangular configuration. Slots
25, 26 are defined at opposite sides of core tower 12 and separate
C-shaped segments 22, 23 of the tower. Corresponding slots 27 are formed
in core tower 10, which is here shown identical to core tower 12. Slots 27
extend upwardly from adjacent the base of the core tower to the point at
which the two C-shaped sections forming the tower are joined.
As illustrated by FIGS. 1 and 2, each floor slab, such as slab 15, has a
major portion 30 which surrounds core towers 10, 12. In addition,
secondary portions 32 contiguous to major portion 30 pass through the
slots separating the confronting C-shaped segments of core towers 10, 12
to bridge the slots. It is preferred that secondary portions 32 span the
spatial interval between the tower sidewalls which define the slots. As a
result, floor slab 15 surrounds core towers 10, 12, bridges the core of
the tower, and occupies the spatial interval between the tower walls which
define the slots.
As is evident from viewing FIGS. 1, 2 and 3, each floor slab such as 15 has
a plurality of folds formed therein, these folds forming upwardly exposed
concavities. A central fold 34 traverses the length of floor slab 15
including its secondary portions 32. Central fold 34 comprises a depressed
planar portion 36 and upwardly inclined side portions 37, 38 contiguous to
the rest of the floor slab. A peripheral fold 40 is formed around the
border of floor slab 15 and includes a depressed portion 41 and an
inclined portion 42 connecting the depressed portion with the remainder of
the floor slab.
Transverse folds 44 are formed on the opposite sides of the respective core
towers 10, 12 and are connected by folds 45. Each fold 44, 45 includes a
depressed portion 46 and an inclined side 47 joining the depressed portion
to the remainder of the floor slab. As will be illustrated in more detail
hereinafter, folds 34, 40, 44 and 45 provide beam paths for reinforcing
and stiffening the floor slab.
As described above, a plurality of floor slabs 15-20 are formed, one on top
of the other, at the base of core towers 10, 12. To avoid the necessity of
providing spacers between the floors, these floor slabs are dimensioned to
"nest" at the base of the core towers, as illustrated in FIG. 3. By
"nesting" it is meant that the lower surface of each floor slab is
conformed to the upper surface of the underlying floor slab so that no
spaces or gaps exist between the floors when they are stacked on top of
each other.
In order that the floors nest when they are stacked one on top of another,
it is essential that the vertical dimension of each floor slab is
maintained constant. This constant vertical dimension must be maintained
not only along the horizontal portions of the floor slab, but along the
inclined portions of the fold as well.
The true thickness of each inclined portion of the floor slabs, such as
inclined sidewalls 37, 38 of central fold 34, is equal to the vertical
thickness of the sidewall times the cosine of the fold angle from the
major planar surface of the floor slab. It will be appreciated that if the
angle of the fold is too large, insufficient thickness of the floor slab
will occur at the folds. On the other hand, if the angle of the fold is
too small, insufficient beam action of the folded plate construction will
result. It is preferred that the fold angle of the inclined portions of
the folds be approximately 45.degree.. However, it is anticipated that the
fold angle may vary from a low of 30.degree. to a high of 60.degree. and
still achieve the objects of the present invention.
The primary advantage of having the floor slabs designed so that they
"nest" is that each floor slab can serve as an underlying form for pouring
of the next uppermost slab. The floor slabs can be formed one by one, and
after each floor slab is allowed to cure, it provides the underlying form
for pouring the next overlying floor slab, greatly reducing the time and
expense of forming the floors. It is apparent that if the floors do not
"nest", i.e. gaps are provided between the various parts of the floor
slabs, forms or spacers would have to be inserted on each floor slab so
that the next overlying floor slab can be poured, greatly complicating the
process of forming the floor slabs at the base of the core towers.
It should be understood that it is an adaptation of the present invention
to form the floor slabs one at a time at the base of the core towers and
elevate that floor slab to its raised position prior to pouring the next
floor slab.
When the first floor slab 15 is to be raised to its elevated position, a
stiffening beam 50 is inserted in the central fold 34 running the length
of the slab. Also, stiffening beams 52, 53 are placed in the folds 40 at
the border of the floor slab. Corresponding beams are placed in the
remaining folds in the slab. As illustrated in FIG. 4, such stiffening
beams in the preferred embodiment of the present invention comprise
reinforced concrete members. The stiffening beams can be poured in place
concrete, precast concrete, or partially precast and partially poured in
place. It is apparent that other stiffening members such as steel I-beams
could also be used in the beam paths.
The uppermost floor slab 15 containing stiffening beams such as 50, 52 and
53 is elevated to its preselected raised position as illustrated in
phantom at 15. In its raised position, floor slab 15 is connected to the
sidewalls of the core towers such as core tower 10 on opposite sides of
the slots by a plurality of bolts 60 as illustrated in more detail in FIG.
7. Each bolt 60 projects through the inclined portion 47 of fold 44 in
floor slab 15, through a medial portion of a precast stiffening member 62
inserted in the fold and through the sidewall of core tower 10.
Complementary to each bolt 60 a cylindrical indentation 64 is formed in the
inner surface of core tower 10, and a steel plate 66 is placed within the
groove and conformed thereto. One surface 68 of steel plate 66 is parallel
to the inclined portion 47 of fold 44.
Each series of bolts in each of the beams passes normally through the
portion 68 of plate 66 and fold 47 in slab 15. A steel plate 70 is welded
or otherwise engaged with one end of bolt 60 to secure it to floor slab
15, and the other end of bolt 60 is threadably engaged with nut 72 so that
the bolt acts as a tension member to provide vertical support to floor
slab 15. To further support the floor slab, grout 74 can be inserted
between the floor slab 15, precast beam 62 and the sidewall of core tower
10.
It should be understood that three components of floor support are provided
by the plurality of bolts 60 to each beam in each floor slab such as floor
slab 15. First, the bolt provides a vertical component of support which
prevents the floor from falling along the path it has been raised.
Secondly, the bolt includes a horizontal component of support which
presses the floor at its edge into the tower sidewalls. Thus, both the
floor and the edge of the precast stiffening member 62 are compressed
against the tower sidewalls at a concrete to concrete interface. This
compression of the concrete to concrete interface together with the high
static coefficient of concrete on concrete provides an additional force to
support the floor.
Finally, it will be noted that the floors span outwardly -- usually in a
cantilevered fashion -- from the edges of the tower sidewall. This
cantilevering of the floor edges further compresses the floor at the tower
sidewall against the tower sidewall. A further compression with a further
static resistance of floor movement relative to the tower results.
The uppermost slab such as 15 forms the roof of the building structure when
it is raised to its elevated position. After floor slab 15 has been raised
to its elevated position, stiffening beams are inserted in the folds of
the next uppermost floor slab 16, as illustrated in FIG. 5. After
insertion of the stiffening beams in slab 16, a curtain wall 80 can be
erected on floor slab 16. Floor slab 16 is thereafter raised to its
preselected elevated position as illustrated in FIG. 6 so that the upper
edge of curtain wall 80 mates with the lower surface of floor slab 15.
Stiffening beams are then added to the next uppermost floor slab 17 and a
curtain wall 81 installed thereon. Floor slab 17 is thus ready to be
raised into position, and stiffening beams and the curtain wall can
thereafter be added to floor slab 18. The process is repeated until an
entire building has been formed and all of the floor slabs are raised into
their preselected elevated positions.
When each of the floor slabs has been raised into position, the floor slabs
with their associated stiffening beams define not only the floors of the
structure external to the core towers, but also lobby floors spanning the
width of the towers themselves. Unimpeded shafts are provided on each side
of the lobby floors within the core towers for the installation of
elevator shafts, fire stair shafts, service shafts and the like.
The secondary portions of the floor slabs which span the slots in the core
towers not only provide lobby floors, but also provide a path for a floor
stiffening and reinforcing beam centrally located along the longitudinal
axis of the building. Because of the central beam path, the central
corridor of the building will have a depressed ceiling. Moreover, the
ceiling at the borders will also be depressed because of folds 40.
However, intermediate portions of the ceiling will be raised to allow for
the convenient installation of heating, ventilation and airconditioning
conduits emanating from the core tower. No intermediate stiffening beams
are provided which would interfere with the placement of such conduits.
The only position where such a conduit cannot be conveniently placed is
along the center beam stiffener, but a central corridor is ordinarily
located at this position, which corridor need not be heated or ventilated.
It is apparent that as the floor flabs are raised and fastened in position,
structural loads will be imposed on the core towers so that they will tend
to deflect inwardly or outwardly at the slots formed therein. However,
each floor slab is attached to the sidewalls of the core towers on each
side of the slot to resist such buckling and provide structural stiffness
to the core towers. When all of the core towers have been raised into
position, such structural stiffening will be provided along the entire
height of the respective towers.
While a preferred embodiment of the present invention has been illustrated
in detail, it is apparent that modifications and adaptations of that
embodiment could occur to those skilled in the art. For example, it is not
essential that two core towers be used, but rather one, three or any
number of such towers may be employed. Furthermore, it may be desirable to
form only a single slot in a core tower, and also it may be desirable to
have secondary portions of the floor slab which do not fully span the core
tower. However, it is to be expressly understood that such modifications
and adaptations are within the spirit and scope of the present invention,
as set forth in the following claims.
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