RZehr wrote: ↑Wed Mar 27, 2024 1:18 pm
I’ll guess that they throw up a temporary bridge within 8 months. And then a new permanent one will take longer than…I’ll guess 4 years.
I'm not an engineer and therefore not an expert on any of this. But I'm not imagining how they could put up a temporary bridge for a span this wide.
Temporary bridges would make sense for a small river or something where you can just drop a truss in place until you get a better bridge made. But this is a 1.5 mile span. Seems like it would be just as much work to build a temporary bridge as a permanent one.
The question in my mind is whether they re-use the existing support pylons for the old bridge, or build new ones and move the new bridge to a different spot along side the old one. I would expect that they will probably have to build all new pylons because the one that was hit by the ship will obviously be damaged. And the others are all 50 years old and concrete has a finite life span in salt water. So if you are going to spend billions putting in new bridge decks and trusses, you are going to want it to be sitting on support structures that will have the same life span as the rest of the bridge.
If they are going to move the new bridge then there is no reason why they can't start with the construction on the new one immediately, even before the old one gets cleared away.
If the Corps of Engineers can build a floating harbor practically overnight (see Gaza thread), surely they can handle a temporary bridge. Reportedly they have 1100 specialists working on this already.
Whether or not they build an entirely new bridge as a replacement, they will temporarily restore the existing one, and in far less time since only the six collapsed spans need to be replaced, not the entire 1.6 miles. The support that was directly hit will need major reconstruction, but probably only minor repairs to the rest of the supports. The spans themselves can be partially fabricated off-site, perhaps even using the original design.
Floating bridges are used in the Seattle area and elsewhere in Puget Sound where glacial carved lakes and fjords are too deep for traditional pylons. For example, many parts of Puget Sound are over 600 ft deep compared to say about 21 feet average depth for the Chesapeake Bay.
But they are not fast to build unlike a floating harbor because they have to account for currents, tides, and such. So they take massive concrete floats and anchor them to the sea floor and then install roadways on top. The floating bridges in Seattle took multiple years to complete.
Last edited by Ken on Wed Mar 27, 2024 5:33 pm, edited 1 time in total.
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A fool can throw out more questions than a wise man can answer. -RZehr
I'm not an engineer and therefore not an expert on any of this. But I'm not imagining how they could put up a temporary bridge for a span this wide.
Temporary bridges would make sense for a small river or something where you can just drop a truss in place until you get a better bridge made. But this is a 1.5 mile span. Seems like it would be just as much work to build a temporary bridge as a permanent one.
The question in my mind is whether they re-use the existing support pylons for the old bridge, or build new ones and move the new bridge to a different spot along side the old one. I would expect that they will probably have to build all new pylons because the one that was hit by the ship will obviously be damaged. And the others are all 50 years old and concrete has a finite life span in salt water. So if you are going to spend billions putting in new bridge decks and trusses, you are going to want it to be sitting on support structures that will have the same life span as the rest of the bridge.
If they are going to move the new bridge then there is no reason why they can't start with the construction on the new one immediately, even before the old one gets cleared away.
If the Corps of Engineers can build a floating harbor practically overnight (see Gaza thread), surely they can handle a temporary bridge. Reportedly they have 1100 specialists working on this already.
Whether or not they build an entirely new bridge as a replacement, they will temporarily restore the existing one, and in far less time since only the six collapsed spans need to be replaced, not the entire 1.6 miles. The support that was directly hit will need major reconstruction, but probably only minor repairs to the rest of the supports. The spans themselves can be partially fabricated off-site, perhaps even using the original design.
Floating bridges are used in the Seattle area and elsewhere in Puget Sound where glacial carved lakes and fjords are too deep for traditional pylons. For example, many parts of Puget Sound are over 600 ft deep compared to say about 21 feet average depth for the Chesapeake Bay.
But they are not fast to build unlike a floating harbor because they have to account for currents, tides, and such. So they take massive concrete floats and anchor them to the sea floor and then install roadways on top. The floating bridges in Seattle took multiple years to complete.
I think the area could handle an extended closure of I-695 better than an extended closure of Dundalk and Seagirt Marine Terminals.
A certain poster has assured me that all young people and other vibrant individuals required to run an economy want to live in cities like Baltimore so they can just stay there and be self sufficient, since out in the hinterlands nobody wants to live and farming/agriculture has no future. Plus cars are bad anyway right? People can switch from driving cars to bicycles and walking. Baltimore has lots of walkable neighbourhoods.
They can also get around by train and deliver freight by train, since that’s better than the evil truck spewing CO2 emissions, right? The Key bridge had no rail lines, despite Biden’s memories that he went across it on a train many times.
Josh wrote: ↑Wed Mar 27, 2024 6:05 pm
Reroute truck traffic to I-81 and I-270/70/76.
A certain poster has assured me that all young people and other vibrant individuals required to run an economy want to live in cities like Baltimore so they can just stay there and be self sufficient, since out in the hinterlands nobody wants to live and farming/agriculture has no future. Plus cars are bad anyway right? People can switch from driving cars to bicycles and walking. Baltimore has lots of walkable neighbourhoods.
They can also get around by train and deliver freight by train, since that’s better than the evil truck spewing CO2 emissions, right? The Key bridge had no rail lines, despite Biden’s memories that he went across it on a train many times.
So your take is why bother even rebuilding the bridge?
That's one take I guess.
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A fool can throw out more questions than a wise man can answer. -RZehr
Recently I was looking at pictures of infrastructure repair after WW2 and I noticed they rebuilt bridges of identical design back on the same abutments and piers. I never see this today, the new bridges are built along side the old which are left to natural decay.
I'm not an engineer and therefore not an expert on any of this. But I'm not imagining how they could put up a temporary bridge for a span this wide.
Temporary bridges would make sense for a small river or something where you can just drop a truss in place until you get a better bridge made. But this is a 1.5 mile span. Seems like it would be just as much work to build a temporary bridge as a permanent one.
The question in my mind is whether they re-use the existing support pylons for the old bridge, or build new ones and move the new bridge to a different spot along side the old one. I would expect that they will probably have to build all new pylons because the one that was hit by the ship will obviously be damaged. And the others are all 50 years old and concrete has a finite life span in salt water. So if you are going to spend billions putting in new bridge decks and trusses, you are going to want it to be sitting on support structures that will have the same life span as the rest of the bridge.
If they are going to move the new bridge then there is no reason why they can't start with the construction on the new one immediately, even before the old one gets cleared away.
If the Corps of Engineers can build a floating harbor practically overnight (see Gaza thread), surely they can handle a temporary bridge. Reportedly they have 1100 specialists working on this already.
Whether or not they build an entirely new bridge as a replacement, they will temporarily restore the existing one, and in far less time since only the six collapsed spans need to be replaced, not the entire 1.6 miles. The support that was directly hit will need major reconstruction, but probably only minor repairs to the rest of the supports. The spans themselves can be partially fabricated off-site, perhaps even using the original design.
Floating bridges are used in the Seattle area and elsewhere in Puget Sound where glacial carved lakes and fjords are too deep for traditional pylons. For example, many parts of Puget Sound are over 600 ft deep compared to say about 21 feet average depth for the Chesapeake Bay.
But they are not fast to build unlike a floating harbor because they have to account for currents, tides, and such. So they take massive concrete floats and anchor them to the sea floor and then install roadways on top. The floating bridges in Seattle took multiple years to complete.
The Patapsco River is not Lake Washington. Currents can be really strong here due to the force of tides. There is an additional complication of Fort Carroll, so you can only use one side if you want a parallel. There is some talk down here about a tunnel. Whatever it is, the top end beltway is seizing up with the truck traffic. You can't even go through the tunnels with a single, sealed propane cylinder. I expect that sooner to later you will see a bridge, how long is anyone's guess.
A crane arrives tonight. Job 1 is to free the ship, which is actually grounded as well as stuck under the wreckage of the bridge. In short, a mess.
Some the containers that were breached contain hazardous materials, so they are getting them involved. Politicians are squabbling, as they do. My new prediction of a replacement bridge-Not in my lifetime.
Josh wrote: ↑Wed Mar 27, 2024 6:05 pm
Reroute truck traffic to I-81 and I-270/70/76.
A certain poster has assured me that all young people and other vibrant individuals required to run an economy want to live in cities like Baltimore so they can just stay there and be self sufficient, since out in the hinterlands nobody wants to live and farming/agriculture has no future. Plus cars are bad anyway right? People can switch from driving cars to bicycles and walking. Baltimore has lots of walkable neighbourhoods.
They can also get around by train and deliver freight by train, since that’s better than the evil truck spewing CO2 emissions, right? The Key bridge had no rail lines, despite Biden’s memories that he went across it on a train many times.
You tuning into our illustrious Mayor? Election is in may, you know.
Judas Maccabeus wrote: ↑Thu Mar 28, 2024 9:09 pmPoliticians are squabbling, as they do. My new prediction of a replacement bridge-Not in my lifetime.
I say Amen to this guy's recommendation.
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The old woodcutter spoke again. “It is impossible to talk with you. You always draw conclusions. Life is so vast, yet you judge all of life with one page or one word. You see only a fragment. Unless you know the whole story, how can you judge?"
