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The construction method of the Simple
and Continuous P.S.C beam by Up-Down method |
x Characteristic
1. The explanation of method
¡ßThe construction method of the Simple P.S.C
beam(composite bridge)by Up-Down method
(Patent
a public notice Number. 10-1999-04582)
In
this method, after setting the girder, raises the middle
point of girder by the temporary support.
And then, come down after installing slab, introduce
the 2nd compressive force into the
lower part of girder.
¡ßThe
construction method of the multiple continuous P.S.C beam(composite
bridge) by Up-Down method
(A
Patent Number. 10-283603-0000, Patent a public
notice Number. 10-2000-054500)
(The
new method No.270 appointed by MOCT[Ministry of Construction&
Transportation])
There
are no controls about the negative moment which is occurred
on the inner support among the
successive bridge methods which have been constructing.
Therefore there are lots of cracks on the slab concrete.
It deteriorates the strength
and durability of the structure. Especially in the case of PSC beam bridges, We build
the beam, which has built in the shape of a simple
beam, the successful shape of cross beams and slabs.
As time goes on, the re-shearing
of moment caused by creep and dry shrinkage bridge in getting bigger. Finally, those cracks give
the structure hurtful effects.
In shorts, the movement of the structure seems to be
a simple beam or is similar
to it, it produces both a huge amount of moment in the
place where positive moment
occurs. It also produces deflection as well as vibration.
Therefore, it gives a very bad effect on utility and
durability. This method
is that. Simply place PSC beams which have made in the
factory or field, then connect
it perfectly using the method which we noticed you.
After that, through Up-Down
of the outer end-point, introduce the 2nd compressive
force into the lower part of PSC beam and the compressive stress corresponding
to the tensile stress after compositing into the slab
concrete of inner support. This
method is applied to build a new PSC beam(composite bridge) and improve the capacity.
This method can be prevent the slab cracks and
breakdown which have been considered on the inner support
of the existing PSC continuous
bridge. As so, making the decrement of support less
than the increment, it has a
effect which introduce the compressive stress in addition
on the place where positive moment occurs. In case of
3 span continuous, make both end-supports come down and
raise.
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¡¡
The construction method of the
Simple and Continuous P.S.C beam by Up-Down method |
 New method
1. Simple bridge
After
placing the girder, raises the middle point of girder by
the temporary support and constructing the slab, come
down it.
placing the
girder & assembling the reinforcing rod of
slab
¡¡ |
setting the
temporary support & raising the girder
¡¡ |
concreting
the slab & curing
¡¡ |
eliminating
the temporary support & coming down the
girder
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The construction method of the
Simple and Continuous P.S.C beam by Up-Down method |
manufacture method
2. continuos bridge
placing
the girder, connecting PSC beams and
arranging the reinforcing rod of slab
¡¡ |
concreting
and curing the slab in the occurring area of
positive moment
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coming down the outer
end-point(introducing the 2nd compressive
force into the lower part of beam)
¡¡ |
concreting and curing the
slab in the occurring area of negative
moment
¡¡ |
raising the
outer end-point
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The construction method of the
Simple and Continuous P.S.C beam by Up-Down method |
Effcets
1. The reducing section of Continuous
P.S.C beam and the effect of span extension by Up-Down
method
Comparing application of Up-Down
method and the reducing section of girder obtained by
the continuity of girders, the effect of span extension
with a exiting
¡¡
Division
¡¡ |
A |
B |
H |
L |
H |
L |
a standard(the standard
diagram of KOREA HIGHWAY CORPORATION)
¡¡
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1.75 |
25 |
30 |
¡¡ |
application
to
Up-Down
method |
2 span continuity
¡¡
|
estimation |
1.3 |
32 |
1.5 |
38 |
difference |
25.7 % Down |
28% Up |
25% down |
26.7% Up |
3 span continuity
¡¡
|
estimation |
1.3 |
36 |
1.52 |
41 |
difference |
25.7% down |
44% up |
24% down |
36.7% up |
-Design live load is DB24 or DL24
-A is
the case that PSC beam length on a standard
diagram of KOREA HIGHWAY CORPORATION is 24m
and B is the case that PSC beam length on a
standard diagram of KOREA HIGHWAY CORPORATION is
30m.
-The effect of Height reduction is
based on same span to a standard diagram of
KOREA HIGHWAY CORPORATION.
-The effect of
span extension is based on same section to a
standard diagram of KOREA HIGHWAY
CORPORATION.
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The construction method of the
Simple and Continuous P.S.C beam by Up-Down method |
The effect of span
extension
1. simple bridge
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The construction method of the
Simple and Continuous P.S.C beam by Up-Down method |
2 span continuous
bean
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The construction method of the
Simple and Continuous P.S.C beam by Up-Down method |
3 span continuous
beam
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The construction method of the
Simple and Continuous P.S.C beam by Up-Down method |
The effect of
Height reduction
(when span was maintained uniformly
and height was minimized)
1. simply bridge
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The construction method of the
Simple and Continuous P.S.C beam by Up-Down method |
2 span continuous
beam
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The construction method of the
Simple and Continuous P.S.C beam by Up-Down method |
3 span continuous
beam
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The construction method of the
Simple and Continuous P.S.C beam by Up-Down method |
The effect of
reduction section
(when span was maintained uniformly
and section was minimized)
1. simple bridge, 2,3 span
continuous bridge
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The construction method of the Simple
and Continuous P.S.C beam by Up-Down method |
How to connect inner
support
The most important things to
connect to make PSC Beam continuous longitudinally is that
how to control the bending tensile stress of the upper and
the bending compressive stress of lower part which occur
by dead and live load.
1. A method
To prevent the
bending tensile stress which occurs upper part of continuous
support, you should connect directly two beams with a
chemical anchor which applied to upper flange concrete of PSC Beam. In case of compressive stress which occured the
lower part of girder can be connected easily with using the
connection member(Figure a, b). On the Figure a, b, the
concrete projecting part is used to connect between two
girder easily, not to get a merit in movement.
(
Fig. a )
( Fig. b)
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The construction method of the Simple
and Continuous P.S.C beam by Up-Down method |
B method
The other method to connect inner support is
that you should connect the extra-reinforcing rod in the
upper flange of PSC Beam to cope with the bending tensile
stress which can occur on the continuous support of upper
girder. You can also put a horizontal connection member
to connect those two girder to improve the possibility of
connection to cope with those problems.
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The construction method of the Simple
and Continuous P.S.C beam by Up-Down method |
The construction
method of the Simple P.S.C beam by Up-Down method
This method is that. In case of the simple
composite construction-process, one end treats with
the fixed end and another end treats with the moving.
Introducing the slab concrete of the negative moment
area in the fixed and the lower flange of the positive
moment into the compressive stress by making the
moving go up and down. because of distributing the moment on the abutment in
the fixed which has the possibility to occur the large
moment in this method, reduce the stress of beam to
external force. Therefore, you expect the reduction
effect which about 20% in the girder-height and span
and the extension effect. It can reduce the number of
the extension joint and the lower shoe by getting the
parapet wall of the abutment which treat with the
fixed and the slab concrete to concrete in a unity. Therefore it has a great effect in a way of
maintenance and management. And because of the
statically indeterminate system, it has a great effect
of the energy distributed and owing to that, you also
obtain a great earthquake resisting ability.
 
After placing simply the PSC Beam in
between abutments, connect the shoe part(1) of abutment
and PSC Beam(2) for making the one end to the fixed.
After that, bury the H shape steel in the shoe part(1)
and weld the connection plate for connecting the lower
flange of PSC Beam above H shape steel. Subsequently,
weld the plate which was buried in lower flange
concrete of PSC Beam in a perfect connection. Where,
you have already pulled out the reinforcing bar from
the shoe part(1) of abutment, parapet wall(7) and PSC
Beam and concrete the upper slab with the shoe
part(1), parapet wall(7) and PSC Beam together. So, it
can play a role of a perfect fixed support.
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The construction method of the Simple
and Continuous P.S.C beam by Up-Down method |
Rahmen shape simple span
PSC composit beam by up and down.
Rahmen shape simple span PSC composit beam |
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After PSC
beam si simplicity deferment, A state of one end
fixed and another end descent. |
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A state of
setting floor-plate concrete at entire a section |
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After curing
floor-plate concrete, A state of import compress
stress at floor-plate concrete by rising
movement hinge |
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