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The construction method of continuous preflex bridge
with a lighting up-down support
A basic concept is to devisionally
manufacture preflex beams according to span , in order to continue
preflex composite beams, that is, when preplex composite beams are
designed, the area of positive moment is similarly manufactured
with simple preflex composite beam. But in the area of negative
moment, a inner support is lifted up and bottom slab is placed,
later a inner support is lifted down. this purpose is to introduce
compressive stress in order to cancel a tensive stress by
a dead and live load.
The merits of this method follow;
It has no expansion joint. This
method is economical.Because a material, self-load and construction
time can be reduced.
Fig. 1 Structural diagram
of 2 spans simple preplex bridge |
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Fig. 2 Structural diagram
of 2 spans continuous preplex bridge |
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Construction method of 2 spans continuous preflex composite
beam
Step1
Placing beams |
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Step 2
Loading of preflexion |
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Step 3
Placing concrete at lower
flange and unloading |
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Step 4
Movement of a second support |
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Step 5
The lifting up a connected
support |
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Step 6
The placing concrete of bottom
and web at inner support |
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Step 7
The lifting down a connected
support |
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Step 8
The placing concrete of bottom
and web at positive moment area and of lower flange
at negative moment area |
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Step 9
Paving a bridge with asphalt |
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Construction method of 3 spans continuous preflex
composite beam
Step 1
Placing beams |
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Step 2
Loading of preflexion |
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Step 3
Placing concrete at lower
flange and unloading |
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Step 4
Movement of a second support |
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Step 5
The lifting up a connected
first support |
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Step 6
The placing concrete of bottom
and web at inner first support |
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Step 7
The lifting down a connected
first support |
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Step 8
The lifting up a connected
second support |
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Step 9
The placing concrete of bottom
and web at inner second support |
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Step 10
The lifting down a connected
second support |
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Step 11
The placing concrete at all
of positive moment areas |
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Step 12
Paving a bridge with asphalt |
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