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8/4/2019 Deck Slab Concreting- Aug 2011
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DECK SLAB POURING SEQUENCE
Sequence of deck slab concreting shall follow as per drawing no: CS/S-12. Rev 2. and the
purpose is to minimize upward deflections in previously placed spans.
For continuous steel bridges with span lengths greater than 200 feet. The deck placementsequence guidelines are below:
1. Positive moment spans shall be poured prior to pouring negative moment area;2. Construction joints at each point of dead load contraflexure point shall be shown in the
deck placement plan;
3. Longer span between points of contraflexure shall be placed before shorter adjacent span.4. Positive moment pours in adjacent spans shall be separated by 72 hours;
In order to minimize the shrinkage of the deck, the selective of low shrinkage concrete mix and
concreting time had been limited; only allow the concreting work at evening time with the lower
temperature. It is to prevent the aggressive loss of water through evaporation process during thehot day.
The following figure illustrates the deck placement sequence for the Batukawa Bridge .
It consist 8 spans with total length of 292m. The total of 15 pouring required for the whole
bridge.
PREPARATION BEFORE CONCRETING
M+ M+M+M+M+M+M+M+ M-M-M-M-M-M- M-
Abutment
A
Abutment
B
1324 5768 9111012 1314 15
Sealing gap using between formwork and
girders
Cleaning the formwork before concreting
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CHECKING BEFORE CONCRETING WORK
Inspection for formwork-
Formwork support and tie rodFormwork dimension
Gap for formwork checked and sealed
Cleanliness of formworkDepth of concreting
Inspection for Reinforcement bar-Size and spacing of rebar checkLapping
Concrete cover/ spacers block checkFinal concrete level marked
Deflection
monitoring rod
Finish level marking
(bottom red tape)
650mm
Sufficient lapping >
600mm
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Sufficient bottom cover and side cover
Expansion joint checked
- Left construction joint at deck slab for future expansion joint installation
Construction joint location checked (As per drawing)
Constructionjoints
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M&E conduit / Pipe / opening installation and checked.
Installation of anchor bolt for hand rail
Drainage outlet for runoff water
Deflection monitoring rod, reserved recess for 30mm cover. The re-bar shall cut off after
monitoring and patch back with cement mortar as cover of deck slab.
Protection of bolt
tread during
concreting
Proper
sealed
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CONCRETING WORKS FOR DECK SLAB
Slump test for pump mix 125 25mm sufficient workability to flow.
Cube prepared 6 nos per set (3 nos for 7days and 3 nos for 28 days), total of 3 set for 65m
during the 1st pouring. Minimum required 20m per set.
120mm
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CURING FOR DECK SLAB
Cover with plastic sheet after toweling the concrete surface.
Spraying water to prevent aggressive evaporation during day time.
Apply curing
compound sika
Antisol-A
Apply curingcompoundCover withplastic sheet
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CONSTRUCTION JOINTS PREPARATION
Apply retarder at the formwork of the construction joint.
Roughened the surface next day using wire brush to expose aggregates before 2nd
casting.
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Concreting works for parapet handrail and concrete kerb
Concreting works for 3rd
pour deck slab at 19th
Aug 2011.
Checking depth of concrete deck , cover and spacer block Sealed the gap between formwork and steel girders with sponge
Road Kerb .
Parapet
handrail
Tie Rod
Formwork
support
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Sufficient vibrate at the edge and construction joint area.
Checked and marked finish level
of deck before concreting
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FOOTPATH CONCRETE COVER
Steel frame for footpath 1 Layer of BMC A5 laid Concreting of footpath concrete cover