It does look reasonable to have such a buffer. But any preventive measure will have limits as what and how serious an impact it can deal with.
In this case the ship this massive is something that is carrying ridiculous inertia, and its highly unlikely even a buffer could stop such an impact.
I think at some point you are better off solving these issues with more regulation(smaller ships)? Instead of treating this as a engineering problem.
The recent grounding of a large container ship in Baltimore's harbor channel demonstrates that a sufficiently massive berm will stop any ship. What's needed is the will to do something about low-probability but catastrophic events (though large-ship collisions, groundings and fortuitously harmless steering failures are frequent enough that this should not have been dismissed as a low-probability event.)
https://www.cnn.com/2022/03/16/business/evergreen-container-...
In this case, the nearby towers supporting transmission lines across the channel seem to be better-protected against ship collisions than the piers of the bridge.
Secondly, I believe riprap would be preferred to compacted soil (though compacted soil did a pretty good job stopping the Ever Given three years ago.)
Thirdly (and rendering the above moot), what's been done around the replacement Sunshine Skyway bridge in Tampa bay (mentioned in other posts here) shows that protection is, in fact, practical.
In view of these considerations, I'm not even going to check if, for example, xoa considered the energy absorbed by the ship (Update: in fairness, I did take a look at what xoa wrote, and I see that it is you who has introduced the figure of 1000 J/M^3.)
For an introduction to a serious engineering approach to this problem, look here:
https://onlinelibrary.wiley.com/doi/epdf/10.1002/stco.200910...
That said, the dolphin-bulwarks around the Tampa Skyway are interesting. I've sailed through similar and not known their purpose other than to observe that local waterfowl like to line up at them ahead of tidal shifts to catch the fish as they're encouraged by the currents through them.
You guys are doing amateur engineering. Firstly we don't even know what happened here yet. Secondly we don't know the nature of the problem we'd have to solve in protecting any span that would have been at that position. (How deep is the water? How far down to bedrock? Geological nature of the soil? etc etc etc)
It seems almost impossible for us as humans to just give the professionals some time and space to work so we can see what happened. I get that. I even engage in it at times. But you guys are stating things with certainty and almost indignation? Come on fellas.
Just say your peace and admit it's just a wild ass guess that's likely to be wrong in the end like the rest of our comments.
ETA: Thank you bmelton for owning that.
You're right that it's amateur. This isn't remotely what I do. To your point though, I don't have that much confidence that the Skyway bulwarks would do -- I'm sure they're more than adequate in preventing strikes from my 40' sailboat. Probably much more than that. My gut tells me they are inadequate to stop the momentum of 100k tonnes at speed, but if they did SOMEthing, perhaps that would be enough to differentiate between bridge damage and bridge collapse. I can't find any details on how it's reinforced, with what, or how deeply those reinforcements are buried, so this too is wild speculation... but I wonder if it isn't somewhat security theater. My wife is already scared of bridges, and we're Marylanders who frequent that bridge and the (much longer) bay bridge -- putting something down there to calm her nerves enough that she isn't panicking for the duration of every crossing is almost certainly worthwhile, but doesn't leave the nerds much to ponder.
Measuring a satellite image in Google Maps [1] tells me the bridge's central span is more than 300 meters.
I Googled the distances before the post but apparently got the wrong value. Danke!
e.g. https://www.japantimes.co.jp/uploads/imported_images/uploads...
In general I share your sentiment society could do more to insure itself against lower-probability catastrophes. But overbuilding every bridge would probably cost more than rebuilding the occasional one that's taken out when an unusual event like this occurs. Maybe in a different environment that would make sense, like a warzone (although I think even then there's more tendency to rely on redundant infrastructure and mobile, power-at-a-point defense).
https://en.wikipedia.org/wiki/Sunshine_Skyway_Bridge#/media/...
Given how the Skyway collapse is burned into the local consciousness, I suspect some of the benefit comes from their visibility.
I truly don't know how the dolphins would fair against a massive ship strike but I can imagine them doing their job.
(ship passing): https://pbs.twimg.com/media/FPgQhy2X0AE8yw1.jpg
I don’t think that is likely? My intuition is that in order to stay seaworthy ships are constructed with more integrity than that.
I don’t have any hard evidence though, just that I have looked at many ship collision/allision aftermath photos and what you describe is not a failure mode I have seen so far.
but only on per-pillar per-direction and with quite a bit of distance between it and the pillar
one some pictures you can see that the ship barley missed one of them due to the angle it was going at
And while I'm not quite sure what it is for the bridge had concrete pillars orthogonal in front of the pillars (this picture shows them well, to be clear I do NOT mean the power line isles: https://www.upi.com/News_Photos/view/upi/7191ba50f17c5a68307...). They would have stopped the ship if it would have went orthogonal to the bridge (i.e. if they mistook where the pillar where in a otherwise normal situation). Through not sure if that was the purpose of them.
But I guess I thought that maybe there was... typically some kind of earthen buffer around the pillar to prevent such an impact?
That's probably impractical too, I guess.
I guess I just didn't realize ~$1bn bridges were one fluky ship accident away from total collapse at any given time. I think maybe I prefer my previous state of ignorance, to be quite honest....