deck slab concreting- aug 2011

8/4/2019 Deck Slab Concreting- Aug 2011

1/11

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


2/11

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


3/11

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


4/11

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


5/11

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


6/11

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


7/11

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.


8/11


9/11

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


10/11

Sufficient vibrate at the edge and construction joint area.

Checked and marked finish level

of deck before concreting


11/11

FOOTPATH CONCRETE COVER

Steel frame for footpath 1 Layer of BMC A5 laid Concreting of footpath concrete cover

deck slab concreting- aug 2011

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