What Kind Of Deck is this?

[roadman65]

https://goo.gl/maps/v8Lmz84YMLkGPjJn7
Noticed that it's got steel mixed in with the concrete. 

If it's the same deck NYC uses on the Manhattan, Brooklyn, and Williamsburg Bridges it was bad traction in the former days of snow tires as my dad's car used to slide driving across those bridges when he had snow tires on his wheels.

[Big John]

Steel grid with concrete fill.

[jeffandnicole]

And it'll be meeting the wrecking ball soon, as NJDOT is getting ready to replace the overpass.

[SectorZ]

https://goo.gl/maps/USbcw6oJ5FzcAjYj9

Something similar on MA 125 in Haverhill MA.

[roadman65]

Steel grid with concrete fill.

What purpose does it serve?

[formulanone]

Steel grid with concrete fill.

What purpose does it serve?

Spanning a body of water so traffic does not sink, it seems.

[wriddle082]

Steel grid with concrete fill.

What purpose does it serve?

If I were to guess, maybe for traction to help with slowing down?  I remember the original Russell-Ironton Bridge over the Ohio River having a deck like this, or at least partially like this, and it had sharp curves at each end.  I wanna say the deck was like this at the two ends and steel grid only on the main spans.

[triplemultiplex]

I figure that's usually an interim fix to make an old steel deck bridge less noisy.  Fill in the gaps in the grating with concrete and it shuts up the vooooom of tires on the open steel grate.

[Dirt Roads]

https://goo.gl/maps/v8Lmz84YMLkGPjJn7
Noticed that it's got steel mixed in with the concrete. 

If it's the same deck NYC uses on the Manhattan, Brooklyn, and Williamsburg Bridges it was bad traction in the former days of snow tires as my dad's car used to slide driving across those bridges when he had snow tires on his wheels.

Steel grid with concrete fill.

Steel grids with lightweight concrete fill is still used primarily as a bridge deck replacement strategy.  On long bridge spans, contractors can remove and replace a short section of the deck running surface and replace it with the new steel grid deck system the same night.  This allows all lanes of the bridge to be returned to service for the next rush hour.  It is my impression that in the past, the same general type of steel grid deck system was also used for economical reasons (given a certain ratio between the linear price of steel versus the volumetric price of concrete).

If I were to guess, maybe for traction to help with slowing down?  I remember the original Russell-Ironton Bridge over the Ohio River having a deck like this, or at least partially like this, and it had sharp curves at each end.  I wanna say the deck was like this at the two ends and steel grid only on the main spans.

I figure that's usually an interim fix to make an old steel deck bridge less noisy.  Fill in the gaps in the grating with concrete and it shuts up the vooooom of tires on the open steel grate.

I've never heard of any of the "singing bridges" being retrofitted (or modified) as such, but the only reason that it couldn't be done is a math problem.  If the bridge superstructure is structurally sufficient to handle the extra weight and forces, the deck can be modified to keep the concrete from falling through.  But in the case of a "singing bridge", part of this new bridge deck would actually be "hanging" from the superstructure (rather than being supported by the superstructure).

[Bitmapped]

For fully-filled steel decks, from what I've read, I think it's mostly an ease-of-installation issue. You can have the decks ready to go and drop them into place versus having to set up forms and wait for the concrete to cure with a conventional deck.

For partially-filled decks, there can be a significant reduction in dead weight which can be a major consideration on older structures. I've seen where they filled in cells in tire paths for improved traction. In the case of the bridge over the New River at Thurmond, WV, some cells in the shared vehicle/pedestrian portion were also filled in during a recent rehab to make it easier for pedestrians to cross the bridge.