## Integral bridge deck pour sequence explanation

## Integral bridge deck pour sequence explanation

(OP)

Hi there,

I have been involved with the design of a integral bridge structure that comprises a main steel box girder with a composite deck supporting the carriageway. I am trying to better understand the proposed deck pour sequence.

The pour sequence splits the integral diaphragm pours from the deck pour. Is there a reason this is done separately instead of pouring the integral diaphragm and pier deck at the same time e.g. P1 deck and diaphragm together? See attached image.

I guess another general question would be, why are positive moments commonly poured separately to the negative moments? Is this strictly to reduce shrinkage cracks or are there other reasons? If so what would they be?

I have been involved with the design of a integral bridge structure that comprises a main steel box girder with a composite deck supporting the carriageway. I am trying to better understand the proposed deck pour sequence.

The pour sequence splits the integral diaphragm pours from the deck pour. Is there a reason this is done separately instead of pouring the integral diaphragm and pier deck at the same time e.g. P1 deck and diaphragm together? See attached image.

I guess another general question would be, why are positive moments commonly poured separately to the negative moments? Is this strictly to reduce shrinkage cracks or are there other reasons? If so what would they be?

## RE: Integral bridge deck pour sequence explanation

Positive moment areas are typically poured first. If the negative area is placed first there's a chance it could crack when the positive area deflects. A continuous bridge deck can be placed in one continuous operation if the volume isn't too large (< 360 CY) and set retarders are used.

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## RE: Integral bridge deck pour sequence explanation

## RE: Integral bridge deck pour sequence explanation

www.PeirceEngineering.com

## RE: Integral bridge deck pour sequence explanation