Note: Descriptions are shown in the official language in which they were submitted.
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S P E C I F I C A T I O N
TITLE OF TIIE INVENTION
Prefabricated PC Shelter Structure
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a snowbreak or
windbreak shelter to be laid and erected on a road or
railway and, more particularly, to an arched, pre-
stressed concrete (which will be abbreviated as cus-
tomary to "PC") shelter structure, a pair of unit half
plates for forming an arched unit together to construct
the arched shelter structure when a plurality of pairs
are fastened together side by side, and a process for
prefabricating the paired unit half plates together.
Description of the Prior art
In the prior art, a shelter made of steel is laid
and erected in the field. This execution of construc-
tion is troubled by an extension of term and an in-
crease in cost and has to blockade the traffic over a
long period of time. In addition, the shelter requires
a very heavy expenditure for its maintenance, manage-
ment and repairs because it is made of steel and will
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heavily corrode.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a
light-weight prefabricated PC shelter structure which
can be laid and erected in the field for a short term
so that it will hardly blockade the traffic.
Another object of the present invention is to
provide a strong shelter structure which is reinforced
as a whole by a number of PC steel bars.
Still another object of the present invention is
to provide a shelter structure which is made firm
against an external force by using the PC steel bars
effectively.
A further object of the present invention is to
provide a prefabricated PC shelter structure which uses
a number of generally arched units to fit the windings,
undulations and grades of a road.
A further object of the present invention is to
provide a prefabricated PC shelter structure which is
vbidless and excellent in strength and appearance.
A further object of the present invention is to
provide a pair of unit half plates for forming an
arched unit together to construct the PC arched shelter
structure when a plurality of pairs are fastened to-
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gether side by side.
A further object of the present invention is toprovide a process for prefabricating the paired unit
half plates together.
According to a feature of the present invention,
there is provided a generally arched, prefabricated PC
shelter structure comprising: a plurality of pairs of
unit half plates prefabricated of highly strong con-
crete, any paired two of said unit half plates being
peripherally curved to form a generally arched unit
together when they are assembled to have their tops
abutting against each other; peripherally fastening
means for peripherally fastening the abutting tops of
said paired two unit half plates together to form said
generally arched unit; transversely fastening means for
transversely fastening a plurality of generally arched
units, which are arranged side by side, together to
construct a generally arched PC shelter structure; and
anchor means for anchoring the legs of said paired two
unit half plates to foundations.
According to another feature of the present
invention, there is provided a pair of unit half plates
prefabricated of highly strong concrete and curved
peripherally to form a generally arched unit together,
when they are fastened at their tops abutting against
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each other, thereby to construct a generally arched PC
shelter structure when a plura]ity of generally arched
units are arranged side by side and fastened trans-
versely together.
According to still another feature of the present
invention, there is provided a process for prefabrica-
ting together a pair of unit half plates of highly
strong concrete, which are curved peripherally to form
a generally arched unit together, when they are fas-
tened at their tops abutting against each other, there-
by to construct a generally arched PC shelter structure
when a plurality of generally arched units are arranged
side by side and fastened transversely together, com-
prising the steps of: (a) pumping highly strong con-
crete into an arching form, which is assembled from a
top form frame, a bottom form frame and side form
frames to have both an internal space for forming said
generally arched unit and a plurality of placing ports
arranged peripherally on said top form frame at a
predetermined interval and opened into said internal
space, through the lowermost one of said placing ports
at one side substantially up to the level of said
lowermost placing port; (b) covering said lowermost
placing port; (c) pumping said concrete into said
arching form through the next one of said placing ports
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substantially up to the level of said next placing
port; (d) covering said next placing port; (e) re-
peating the pumping step (c) and the subsequent
covering step (d) at said one side except for the top
placing port; (f) repeating the steps (a) to (e) con-
secutively for the other side of said arching form; (y)
positioning a top form plate at the peripheral center
of said top placing port; and (h) pumping said concrete
into said arching form through said top placing port.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the
present invention will become apparent from the fol-
lowing description taken in connection with four em-
bodiments thereof with reference to the accompanying
drawings, in which:
Fig. 1 is a front elevation showing the whole
structure of an arched PC shelter structure according
to a first embodiment of the present invention;
Fig. 2 is a top plan view showing a portion of the
PC shelter structure of Fig. 1;
Fig. 3 is an enlarged longitudinal section showing
a portion of a unit half plate of the PC shelter struc-
ture of Figs. 1 and 2;
- Fig. 4 is similar to Fig. 1 but shows a second
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embodiment of the present invention;
Fig. 5 is similar to Fig. 2 but shows the PC
shelter structure of Fig. 4;
Fig. 6 a longitudinally sectional front elevation
showing an arching form for prefabricating the unit
half plates in a pair by a process according to a third
embodiment of the present invention;
Fig. 7 is an enlarged transversely sectional side
elevation of the arching form of Fig. 6;
Fig. 8 is a side elevation showing the case in
which four arching forms of Figs. 6 and 7 are arranged
side by side in the longitudinal direction of the
resultant PC shelter structure;
Fig. 9 is similar to Fig. 6 but schematically
shows the arching form which is being placed with
concrete by the process of Figs. 6 to 8;
Fig. 10 is an enlarged longitudinal section
showing a portion of the arching form of Figs. 6 to 8;
Fig. 11 is similar to Figs. 1 and 4 but shows an
arched PC shelter structure according to a fourth em-
bodiment of the present invention;
Fig. 12 is similar to Figs. 2 and 5 but shows the
PC shelter structure of Fig. 11; and
Fig. 13 is an enlarged longitudinal sec-tion
showing a portion oE the PC shelter structure of Figs.
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11 and 12.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in the
following in connection with the embodiments thereof
with reference to the accompanying drawings.
According to a first embodiment of the present
invention, as shown Figs. 1 to 3, a number of PC unit
half plates 3 are prefabricated at a factory. Each of
these unit half plates 3 is formed of highly strong
concrete 1 and tensed by unbonded PC steel bars 2. The
unit half plate 3 may be formed on its outer face with
peripheral (or longitudinal) ribs 4, which extend all
over the length in a curving direction, and on its
inner and outer faces with a number of planes 5a to
form together with the pairing half plate 3 a generally
arched multiplanar unit 5 which has an arched portion
of a polygonal section in the curving or longitudinal
direction. In each of the ribs 4, there is buried the
unbonded PC steel bar 2 which is tensed by a post-
tension and fastened at its two ends by means of not-
shown nuts. The unit half plate 3 is further formed on
its outer face with a plurality of transverse ribs 6
which extend all over the width in a transverse direc-
tion perpendicular to the curving direction. Each of
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these transverse ribs 6 is formed with a duct 7.
In the field, a desired number of the unit hal~
plates 3 thus prefabricated are temporarily assembled
to abut against one another in the curving longitudinal
direction and in the transverse directions. The unit
half plates 3 in each pair are fastened at their upper
ends or tops to each other in their curving longitudi-
nal direction by means of a peripheral fastener 3 such
as a combination of a bolt and a nut. The unit half
plates 3 of the desired number adjoining side by side
are fixed in their transverse direction, i.e., in the
longitudinal direction of the resultant arched PC shel-
ter structure by threading a desired number of trans-
versely fastening PC steel bars 9 into the individual
ducts 7 and by fastening the steel bars 9. Here, these
steel bars 9 to be suitably used may be either unbonded
PC ones which are coated with asphalt or tar so that
they may not be wetted with the concrete or post-
tension PC ones which use sheaths. On the other hand,
the unit half plate 3 may be made of fiber-reinEorced
high strong concrete. The unit half plate 3 has its
lower end (or leg) 10 is positioned on a support
mounted on a foundation 11 and is hinged to the founda-
tion 11 by means of anchor bolts. In an alternative,
the unit half plate 3 may be equipped at its abutting
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top with an elastic member and formed at its leg with a
hinge structure by burying in the foundation 11 a
concrete hinge preformed in the unit half plate 3.
Thus, a light-weight prefabricated PC shelter
structure can be easily laid and erected in the field
without substantially blockading the traffic. This
prefabricated PC shelter structure can be made firm
because it is monolithically constructed of the nu-
merous PC steel bars 2 and 9 in the curving longitudi-
nal and transverse directions of the unit half plates
3. Since the ribs 4 and 6 are formed on the outer
face, moreover, their PC steel bars 2 and 9 can be
effective to provide a shelter structure which is firm
against an external force. Since the unit 5 construc-
ted of the paired unit half plates 3 has a multiplanar
section, furthermore, it is possible to form concrete
into a unit half plate 3 which has an arch half suited
for the windings, undulations and grades of the road.
Turning to Figs. 4 and 5, a second embodiment of
the present invention will be described by denoting the
same portions as those of Figs. 1 to 3 at the common
reference numerals. In this embodiment, each pair of
PC unit half plates 3A, which are to be fastened to-
gether by the transversely fastening PC steel bars 9
into the arched shelter structure, have not the multi-
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planar section, as in the foregoing embodiment, but agenerally continuously curving section. Each unit half
plate 3A is arranged with at least one aperture 12, in
which there is fitted a transparent or semitransparent
face plate 13 of a synthetic resin from the outer or
inner face through a not-shown suitable member to pro-
vide a natural lighting window.
Here, the unit half plate 3A may also be formed on
either its inner face or its inner and outer faces with
ribs 4 and 6 to be arranged with the PC steel bars 2
and 9. Moreover, the generally arched unit may have
their two ends or legs 10 fixed rigidly in the field to
not-numbered posts which are also prefabricated at the
factory.
Turning now to Figs. 6 to 10, there is shown a
process for prefabricating the unit half plates 3 and
3A of Figs. 1 to 5 in accordance with a third embodi-
ment of the present invention. An arching form 21 is
constructed by assembling a top form frame 22, a bottom
form frame 23 and side form frames 24 by not-shown
fastening means. The top form frame 22 is formed with
two rows of, for example, peripheral rib forming por-
tions 25, each of which in turn is formed with seven-
teen placing ports 26 at an equal interval. Reference
numeral 27 denotes an erection structure for supporting
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the arching form 21 thus constructed. As in the prior
art, the concrete is stored in the not-numbered tank of
a concrete pump car 28. In a place near the factory or
field, as shown in Fig. 9, the placing pipe 29 of the
concrete pump car 28 is at first connected to the
lowermost placing port 26 of one side of the arching
form 21 to pump the concrete 30 via the placing pipe 29
into the arching form 21 up to the level of the lower-
most placing port 26 by the action of the concrete
pump. Then, the placing pipe 29 is disconnected from
the lowermost placing port 26, and this placing port 26
is sealed with a not-shown cover. In this state, the
concrete 30 is pumped into the arching form 21 up to
the level of a next placing port 26. Thus, the con-
crete 30 is placed into one side of the arching form 21
consecutively from lower to higher placing ports 26.
After this, the concrete 30 is likewise placed into the
other side of the arching form 21. Finally, the con-
crete 30 is further placed into the highest or top
placing port 26. Here, a top form plate 31 is posi-
tioned at the peripheral center of the top placing port
26 so that the generally arched unit may be divided
into two half plates 3 (of the first embodiment) or 3A
(of the second embodimen-t). The positioning of the top
form plate 31 may be conducted either before or imme-
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diately after the placing of the concrete 30 into thetop form plate 31. It should also be noted that suita-
ble inserts 32 (for the ducts 7 of Figs. 2 and 4) and
not-shown suitable inserts (for the peripheral fas-
teners 8) are positioned in advance in the arching form
21. Meanwhile, the compaction of the concrete is car-
ried out in t1me to the pumping action of the concrete
pump car 28 by means of a high-frequency vibrator for
vibrating the arching form 21.
Thus, in the process of this third embodiment, the
placing pipe 29 of the concrete pump car 28 is connec-
ted to the several placing ports 26 one af-ter another.
These placing ports 26 are formed in the top form frame
22 of the arching form 21 to pump and place the con-
crete 30 sequentially from the bottom to the top of the
arching form 21. As better seen from Fig. 10, there-
fore, the space of the single placing action is re-
stricted to a small one between the two adjacent
placing ports 26 with a small head. This causes the
air to move up sequentially upward, thus preventing it
from being left confined in the concrete 30 and this
concrete 30 itself from segregating. Since, moreover,
the concrete pump car 28 has its placing pipe 29 con-
nected to the placing ports 26 one after another to
sequentially pump the concrete 30 directly into the
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arching form 21 by its concrete pump, it can complete
the concrete placing of the arching frame 21 within a
short period of time. Thus, it is possible to con-
struct an arched PC shelter structure which is voidless
and excellent in strength and appearance.
On the other hand, the number and interval of the
placing ports 26 may be appropriately selected. In
short, the arching form 21 may be equipped with the
placing ports 26 in its right and left sides and its
top to place the concrete 30 sequentially from its
bottom to the top. In Figs. 6 to 8, moreover, the
placing ports 26 are formed in the rib forming portions
25 of the top form frame 22 but may be formed between
the portions 25. In short, it is sufficient that the
placing ports 26 are formed in the top form frame 22.
Still moreover, the rib forming portions 25 of the top
form frame may be omitted but may be formed in the
bottom form frame 23. On the other hand, the arched
shelter structure can fit all the shapes including the
arched multiplanar one. As described above, the
placing ports 26 may be used in the order from the
right and left side ones to top one, and this order can
be appropriately selected within the exemplified range.
On the other hand, the placing pipe 29 to be used with
the concrete pump car 28 may employ suitable means of
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piping or boom type. Suitable means may be selected
for connecting the placing pipe 29 to one oE the
placing ports 26. These placing ports 26 need not be
formed with the projecting mouths, as shown. By the
process thus far described, it is possible to prefabri-
cate pairs of excellent PC unit half plates for the
arched PC shelter structure.
According to a fourth embodiment of the present
invention, as shown in ~igs. 11 to 13, a number of unit
half plates 41 are prefabricated of highly strong con-
crete at a factory. These unit half plates 41 are
paired and assembled together in the field to form
generally arched units 42. These arched units 42 are
then assembled in abutting states and fastened in the
longitudinal direction of the resultant arched PC shel~
ter structure by means of a plurality of fastening PC
steel bars 43, e.g., unbonded PC steel bars which are
arranged at a predetermined interval. Moreover, each
of the unit half plates 41 has its outer face formed
with peripheral or longitudinal ribs 44 and transverse
ribs 44a and its inner face 45 curving generally conti-
nuously. The aforementioned PC steel bars 43 extend
through the transverse ribs 44a. Here, these PC steel
bars 43 are exemplified by the prestressed concrete
steel bars or the unbonded PC steel bars which are
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covered with asphalt or tar so that they may not be
wetted with the concrete, but may be the post-tension
PC steel bars using sheaths. On the other hand, the
unit half plate 41 may be prefabricated of highly
strong concrete reinforced with fibers. Moreover, the
paired unit half plates 41 have their lower ends or
legs 46 hinged to foundations 47 by means of supports
and anchor bolts and their abutting top ends 48 fas-
tened by means of a peripheral fastener 49 such as a
combination of a bolt and a nut. Incidentally, the
unit half plate 41 is arranged therein with at least
one aperture 50, in which there is fitted a transparent
or semitransparent face plate 51 from the outer or
inner face through suitable means such as a retaining
or fitting member to form a natural lighting window 52.
Reference numeral 53 appearing in Fig. 13 denotes a
side flange which is formed to extend from the inner
face of the transversely abutting portion of each unit
half plate 41 thereby to cover the abutting portion.
In the fourth embodiment described above, the unit
half plates 41 are prefabricated in pairs of the highly
strong concrete to form the generally arched units 42,
which are then assembled in the longitudinal direction
of the desired arched PC shelter structure to have
their unit half plates 41 fastened by means of the
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transversely fastening PC steel bars 43. Moreover, the
unit half plate 41 has its outer face formed with the
crossing ribs 44 and 44a extending in the curving and
transverse directions and its inner face curving gener-
ally continuously. As a result, the light-weight
arched PC shelter structure can be easily laid and
erected in the field without substantially blockading
the traffic to reduce the costs for its maintenance and
repairs. Since, moreover, the numerous unit half
plates 41 can be fastened by the transverse PC steel
bars 43, the arched PC shelter structure to be con-
structed can be made firm. Furthermore, the inner face
of the shelter structure is the continuously curving
face 45 so that it can present a fine view, and the
natural lighting windows 52 can present a well-lighted
space in the arched shelter structure. In addition,
fhe ribs 44 and 44a are formed on the outer face to
facilitate the mounting and fastening of the transverse
PC steel bars 43.
The present invention should not be limited to the
four embodiments thus far described but can be modified
in various manners within the gist of itself.
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