Francis Scott Key Bridge (I-695) complete collapse after large ship hits it

[jeffandnicole]

I know we're primarily a road-based community and "omg replace all the roads with rail" people can get silly, but I honestly don't think it's a terrible idea to have some rail space on a new bridge. This new one will likely be used for 50-75 years, so not a bad idea to build in future expandability for something like a rail line in that area.

Mainline RR grades are rarely above 1%. Anything over 2% is pretty extreme. Clearance under the old bridge was 185', and it's likely the new one will be a bit higher. Seems an approach of 3-4 miles on each side would be necessary, which would run from about MD-10 to about the existing railroad near MD-151.

If faulty, someone please correct my math or assumptions.

The clearance should be about the same.  In order to get to this bridge, ships would need to go under the Chesapeake Bay Bridges (186 feet) or thru the Chesapeake-Delaware Canal (a few bridges offer 135 feet of clearance).  Since it's unlikely Delaware has any plans to knock down both Chesapeake Bay Bridges or build a tunnel here, there's no reason to offer more than 186 feet of clearance.

They would be silly to constrain themselves for the future by only building to the existing limitation of other bridges which are significantly older. They have the opportunity to build the next bridge to last 75-100 years. I would absolutely think they'll go with a higher clearance to anticipate a Bay Bridge replacement in the next 20-30 years. And perhaps, if they indeed build this one taller, it could encourage MDOT to look into a replacement with higher limits sooner than later. "Hey, the Port is ready to handle the next upgrade in size of ships and this is the only thing holding that back" would be an argument that could be had if they rebuild Key to be 200-220+ ft clearance.

They've obtained bay bridge addition or replacement proposals already to relieve congestion. Some proposals call for a bridge/tunnel, but not all. I haven't seen anything regarding a  greater clearance height if theres no tunnel involved.

[PColumbus73]

Since this is an emergency replacement, are they only bidding or allowing for an 'in-kind' structure?

[jeffandnicole]

Since this is an emergency replacement, are they only bidding or allowing for an 'in-kind' structure?

No.  The new structure will be a different bridge design than the old structure, and at least one media report mentioned the existing piers on either side will be demolished. 

[davewiecking]

All you wanted to know about the Key Bridge rebuild.
https://www.baltimoresun.com/2024/07/18/key-bridge-rebuild-q-and-a/

[jeffandnicole]

All you wanted to know about the Key Bridge rebuild.
https://www.baltimoresun.com/2024/07/18/key-bridge-rebuild-q-and-a/

Didn't care for this answer: "Also factoring into the calculus is the lifetime of the Bay Bridge. It only has about 15 or 20 more years of life,"

It certainly had more than 15/20 years of life. Not sure what info they used for this. And the question was related to building dolphin barriers a few decades ago, not the day after it was hit. Even if its lifespan was coming to an end, there are numerous ways to repair the bridge and lengthen that timeline. Large bridges like this frequently are reconstructed for this purpose.

Also, if its lifespan were to end in 15 or 20 years, they would already need to be talking replacement. There are years of planning, engineering, design, right of way and other pre-construction activity that would need to be done first. and the actual construction would be about 3 - 4 years, at minimum, at a normal pace.

[epzik8]

In a perfect world, there would be no toll increases resulting from this in the Baltimore tunnels.

[Rothman]

All you wanted to know about the Key Bridge rebuild.
https://www.baltimoresun.com/2024/07/18/key-bridge-rebuild-q-and-a/

Didn't care for this answer: "Also factoring into the calculus is the lifetime of the Bay Bridge. It only has about 15 or 20 more years of life,"

It certainly had more than 15/20 years of life. Not sure what info they used for this. And the question was related to building dolphin barriers a few decades ago, not the day after it was hit. Even if its lifespan was coming to an end, there are numerous ways to repair the bridge and lengthen that timeline. Large bridges like this frequently are reconstructed for this purpose.

Also, if its lifespan were to end in 15 or 20 years, they would already need to be talking replacement. There are years of planning, engineering, design, right of way and other pre-construction activity that would need to be done first. and the actual construction would be about 3 - 4 years, at minimum, at a normal pace.

3-4 years from scoping to construction on a project the size of the the Key Bridge is pretty optimistic.

Then again, the Gov. Mario M. Cuomo Bridge was done pretty darned quickly, all things considered...

[jeffandnicole]

All you wanted to know about the Key Bridge rebuild.
https://www.baltimoresun.com/2024/07/18/key-bridge-rebuild-q-and-a/

Didn't care for this answer: "Also factoring into the calculus is the lifetime of the Bay Bridge. It only has about 15 or 20 more years of life,"

It certainly had more than 15/20 years of life. Not sure what info they used for this. And the question was related to building dolphin barriers a few decades ago, not the day after it was hit. Even if its lifespan was coming to an end, there are numerous ways to repair the bridge and lengthen that timeline. Large bridges like this frequently are reconstructed for this purpose.

Also, if its lifespan were to end in 15 or 20 years, they would already need to be talking replacement. There are years of planning, engineering, design, right of way and other pre-construction activity that would need to be done first. and the actual construction would be about 3 - 4 years, at minimum, at a normal pace.

3-4 years from scoping to construction on a project the size of the the Key Bridge is pretty optimistic.

Then again, the Gov. Mario M. Cuomo Bridge was done pretty darned quickly, all things considered...

No, no. I said after all the prelim stuff is done, *then* it's 3 - 4 years for construction!

[PColumbus73]

Aren't the Tappan Zee and Goethals essentially the same design? Guess that copy-pasting bridge designs doesn't save that much time.

[Henry]

Aren't the Tappan Zee and Goethals essentially the same design? Guess that copy-pasting bridge designs doesn't save that much time.

While I'm not familiar with New York, I'm inclined to say that they are both the same design, as they're twin spans that look exactly alike. But the big difference is that the new Key Bridge will be a single span, as it was the lightest traveled of the three Baltimore harbor crossings, and until some sort of industry explosion happens in its surrounding areas, it will be once again that way.

[bwana39]

Aren't the Tappan Zee and Goethals essentially the same design? Guess that copy-pasting bridge designs doesn't save that much time.

Design work is NEVER cut and paste any more. The level of microengineering details is burdensome and expensive. While you do use the same design standards, the sheets are each done seemingly from scratch.

[jeffandnicole]

Aren't the Tappan Zee and Goethals essentially the same design? Guess that copy-pasting bridge designs doesn't save that much time.

Design work is NEVER cut and paste any more. The level of microengineering details is burdensome and expensive. While you do use the same design standards, the sheets are each done seemingly from scratch.

I've seen people think traffic lights are a standard kit they take out of a box.

While many can be built alike, they all need to be constructed specifically for each location based on minor details present at similar intersections, especially sidewalk ramps, lane and shoulder widths and underground utilities.

[Big John]

Kiewit awarded contract for design build: https://www.cbsnews.com/baltimore/news/mdta-board-approves-key-bridge-rebuild-contract/

[epzik8]

Kiewit awarded contract for design build: https://www.cbsnews.com/baltimore/news/mdta-board-approves-key-bridge-rebuild-contract/

Progress...

[jeffandnicole]

Kiewit awarded contract for design build: https://www.cbsnews.com/baltimore/news/mdta-board-approves-key-bridge-rebuild-contract/

The project is set to begin in 2025, and the replacement bridge is expected to be complete by Fall 2028. Kiewit estimates rebuilding the bridge will cost about $1.2 billion, which is less than the initial projection of $1.7 billion, but a more accurate cost projection will be made halfway through phase one.

Well I think I can see how they won the bid. 

4 years later...oops...it's over $2 Billion.  Blame X, Y, and Z.

[Henry]

So we finally know who will build the new Key Bridge, which means that demolition of the old bridge's remains should begin any minute now.

[jmacswimmer]

Also buried in the announcement is a confirmation that the Broening Highway turnaround will now remain toll-free until the rebuild is completed (it was being re-evaluated month-by-month up until this point).

https://mdta.maryland.gov/blog-category/mdta-news-releases/mdta-board-approves-progressive-design-build-contract-francis

[PColumbus73]

I'm looking forward to what the new bridge will look like.

[The Ghostbuster]

I hope the new bridge is six lanes (three in each direction) with breakdown shoulders on both sides.

[jeffandnicole]

I hope the new bridge is six lanes (three in each direction) with breakdown shoulders on both sides.

I get we want to reach for the stars, but that design - 10 lanes wide total, would be a bridge 2.5 times wider than the previous bridge of 4 lanes.

And there's a considerable distance on both sides of the Key Bridge location which remain 4 lanes total, including the Curtis Creek Drawbridges to the south and several bridges to the north.

There doesn't seem to be any reason why the bridge needs to be 3 lanes wide per direction when the roadway will remain 2 lanes wide per direction on either side of the bridge.

[Sonic99]

I hope the new bridge is six lanes (three in each direction) with breakdown shoulders on both sides.

I get we want to reach for the stars, but that design - 10 lanes wide total, would be a bridge 2.5 times wider than the previous bridge of 4 lanes.

And there's a considerable distance on both sides of the Key Bridge location which remain 4 lanes total, including the Curtis Creek Drawbridges to the south and several bridges to the north.

There doesn't seem to be any reason why the bridge needs to be 3 lanes wide per direction when the roadway will remain 2 lanes wide per direction on either side of the bridge.

My contention would be that it should be built for way further down the road than any of us can envision. The new bridge should hopefully be 60-70+ years lifetime. I'd build in future expandability. Don't have to actually use it in full configuration, but it's a hell of a lot easier in the next 10-15 years to add lanes to the surrounding freeway than it is to underbuild this bridge and then have it be the restriction for a full expansion later on.

[TheOneKEA]

I hope the new bridge is six lanes (three in each direction) with breakdown shoulders on both sides.

I get we want to reach for the stars, but that design - 10 lanes wide total, would be a bridge 2.5 times wider than the previous bridge of 4 lanes.

And there's a considerable distance on both sides of the Key Bridge location which remain 4 lanes total, including the Curtis Creek Drawbridges to the south and several bridges to the north.

There doesn't seem to be any reason why the bridge needs to be 3 lanes wide per direction when the roadway will remain 2 lanes wide per direction on either side of the bridge.

My contention would be that it should be built for way further down the road than any of us can envision. The new bridge should hopefully be 60-70+ years lifetime. I'd build in future expandability. Don't have to actually use it in full configuration, but it's a hell of a lot easier in the next 10-15 years to add lanes to the surrounding freeway than it is to underbuild this bridge and then have it be the restriction for a full expansion later on.

Agreed, and I would also argue that serious consideration for breakdown shoulders is also needed for access by emergency vehicles, especially since this is the designated hazmat crossing of the Patapsco River.

If the areas around the bridge approaches were more residential, I would argue for consideration of a segregated pedestrian facility that would be able to carry foot traffic and bicycles. The industrial nature of the area precludes such a facility from being considered, though, and the MdTA's refusal to provide such a facility on the Nice Bridge is proof of their lack of interest in such a thing.

[epzik8]

There doesn't seem to be any reason why the bridge needs to be 3 lanes wide per direction when the roadway will remain 2 lanes wide per direction on either side of the bridge.

Plus, there's a trend nowadays called cost-cutting.

[PColumbus73]

I think other people here mentioned that AADTs on the bridge indicated that 4 lanes were sufficient, so I think rebuilding the bridge as 4 lanes with shoulders should be more than enough.

If traffic volumes increase later on, a parallel bridge can be built and then alternate bridge replacements every 50 years or so if they show signs of failing.

[jeffandnicole]

If the bridge is built with 2 lanes and a full size right shoulder, then that shoulder becomes the 3rd lane if needed years down the road. 

That's how many bridges have been built over the years where an inkling of an expansion could possibly be needed.