North Washington St Bridge

Jahvon09

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It will be interesting to see just where these will be put in the water! They've hatched from their cocoons. :giggle:
 
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mass88

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How does concrete stand up in water? Is there a special mix they use for these sorts of applications? Or a special coating they use on the bases?
 

Charlie_mta

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How does concrete stand up in water? Is there a special mix they use for these sorts of applications? Or a special coating they use on the bases?
Based on the above photo it looks like they built cofferdams around the concrete footing locations before they placed any concrete. The cofferdams are the sheet piling that keeps the water out of the area that the concrete is poured in,
 

North Shore

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How does concrete stand up in water? Is there a special mix they use for these sorts of applications? Or a special coating they use on the bases?
Concrete by nature is porous. Water, in turn helps hydrate the cement in the mixture and turns it concrete. The main concern with water is corrosion of the rebar. I would imagine that the rebar used was epoxy coated and cut edges were touched up before concrete was placed in the forms.

Admixtures may have also been specified for the concrete mix to further prevent corrosion, as well as spalling from freeze/thaw cycles and saltwater intrusion.
 

Patrick Winn

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Based on the above photo it looks like they built cofferdams around the concrete footing locations before they placed any concrete. The cofferdams are the sheet piling that keeps the water out of the area that the concrete is poured in,
I find it interesting that there is one set of concrete footings by the north end side of the bridge that looks like it’s perpendicular to the bridge itself. Can’t imagine why.
 

bigpicture7

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I find it interesting that there is one set of concrete footings by the north end side of the bridge that looks like it’s perpendicular to the bridge itself. Can’t imagine why.
Not sure specifically what you're referring to, but note that there is a pedestrian walkway bridge that will run underneath the main bridge on the Boston side, between Lovejoy wharf and the North End. You could have been noticing footings for that. Below is a screengrab from a video MassDOT posted on traffic flow that shows the pedestrian walkway.

NorthWash1.png
 
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ceo

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That bridge was originally built a few years ago; it connects to the 2-way cycletrack on Atlantic Ave. It was temporarily removed for the duration of this project.
 

Patrick Winn

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Not sure specifically what you're referring to, but note that there is a pedestrian walkway bridge that will run underneath the main bridge on the Boston side, between Lovejoy wharf and the North End. You could have been noticing footings for that. Below is a screengrab from a video MassDOT posted on traffic flow that shows the pedestrian walkway.

View attachment 14555
In retrospect I think I just saw something that was staged there. But I'm glad you posted. Didn't know about this underpass and I'm glad to see it. There's something similar on the Charlestown side. If only we could do something to fix how awful the Chelsea st and Causeway st. intersections are. I'd love a footbridge over no. washington somewhere.
 

AmericanFolkLegend

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The V-piers are getting a horizontal topping pier. If you look closely at the last picture above you can see the plate washers that pull the V-piers snug with the topping pier. They must have post-tensioned them.
 

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