How Hot is Ukraine Gonna Get?

[chuckdyke]

Something new on Twitter.

 

[FancyCat]

I have seen comments noting that Ukraine continues to overstep Russian red lines, with seemingly little pushback. Even if the bridge reopens without a issue, aside from all the symbolism and other effects mentioned, it leaves the Russian state walking away from prior comments on red lines. Note very little word by Putin and co warning of nuclear retaliation or other escalation for attacking the bridge. If it was a true red line, warnings would be louder. 

A victory still for Ukraine even if their goal had been to destroy Russian logistics, the red line has again shifted, if the bridge is attacked and destroyed in the future, Russian use of escalation is weakened, both Ukraine and the west will be encouraged by this to keep pushing Russia. 

I want to bring up the sentiments of this thread, in how Ukraine has managed to bit by bit, shift our thinking in how Ukraine will operate, what Ukraine's capabilities are, as well as how Russia has lost initiative in the sentiments of the thread, and reflect that in the same manner as how time and Ukraine is changing how we think, the world is having the same done to it, where the Russian reality is ending and the Ukrainian reality is coming into focus. 

I recall stances like suggesting Ukraine would be better served refraining from attacking Crimea, or the Crimean bridge, either for escalation reasons, for operational reasons, it would be better to utilize resources closer to the front, etc. In the same way, I recall worry about Ukraine targeting inside Russia, targeting Russian infrastructure, thinking of wider offensives, the list goes on, as time has gone on, Ukraine is step by step illustrating its ability and resolve, and is not only shifting Russia's red lines, but our own perception of Ukraine and Russia.

The reason why I bring this up, (considering its pretty obvious, our thinking of Ukraine is framed by what Ukraine does), is to emphasize a clear positive movement in favor of Ukraine obtaining "total victory", of Ukraine moving both operationally in a military sense, as well as mentally, to prep the world for a day where Ukraine takes over Crimea. 

I know, maybe I am just wrong. what does a car bomb (or missile. or underwater SOF team. or....boat) compare to invading a island? this car bomb could have cut the only supply line to Crimea. this supply line should not have had this occur, and its viability as a loss in the future has just skyrocketed. this should not have happened, Russia should be able to protect this vital line, and Ukraine's ability to target it, i think one could stay most of us considered impossible a few months ago. Just like Saki. Just like two offensive actions occurring simultaneously. Or a massive long term psyop to turn Kherson into a trap. 

With each succeeding action Ukraine undertakes to undermine Crimea's defenses, Russia is losing more and more of the red line, and the mental fear that it represents, that Russia needs to enforce if it wants to prevent the line being tested via the liberation of the island. 

[FancyCat]

21 minutes ago, chuckdyke said:

Something new on Twitter.

 

Western and Russian opposition journalists have noted nothing out of the ordinary in Moscow, its probably some sort of psyop, probably western focused to emphasize Russian loss of control. 

[Battlefront.com]

4 minutes ago, chrisl said:

The twin towers was a much more complicated structural setup and they survived the collisions just fine.  The heat of the fire weakened the columns and then too many columns started failing to support the floors above them and it collapsed in a domino effect because even full strength floors couldn't support the mass of floors above them piling up.

Sure, I was not trying to make a detailed comparison.  My point is that non-engineers might not know what they are looking at when it comes to catastrophic failures and draw incorrect conclusions.  In the case of the Kerch bridge there's an obvious failure and not necessarily an obvious cause of it.  Instead of presuming some cause we don't have evidence for, it seems to me more prudent to presume the evidence we do have fully explains things.  It's just that we don't know what the explanation is.

An example of this was seen when talking about the Saki hits.  People were saying that the berms around the planes would have protected them from indirect explosive effects so they came up with theories of Ukrainian SOF running around with bags of explosives, drones, and other things that there was no evidence to support.  Instead, the likely cause of the damage to the aircraft was falling debris from the explosions we know happened and/or some other cause.

Specific to Kerch it should be presumed that the single explosion we know of explains everything.  Even the stuff we don't see an immediate and obvious layman's explanation for.  Subs, second detonations, etc. that we have no evidence for should be kept out of the discussion.

4 minutes ago, chrisl said:

The Kerch bridge is a much more straightforward structure - it's a lot like a Hot Wheels track, with segments defined by the longitudinal beams and a relatively thin web of steel and asphalt tying them together.  Each segment is resting across multiple piers and mostly held in place by gravity with some flexible constraints to keep it from cracking due to thermal expansion/contraction and wind.  The two decks don't appear to be really tied together - they rest separately on their piers, which are pretty solid (though susceptible to earthquakes and ice), isolated by the bearings that accommodate the expansion/contraction.  So very little of the force that went into the outer deck was transmitted to the inner deck through the structure, and it's just the pressure from the shock wave that did moderate damage to the deck and railing.  

Yup, that sounds perfectly reasonable.  Or put more simply... we have one known explosive event and two different results, therefore a reason for the difference exists.  It's probably some physics that an engineer could verify, not a dolphin with a frick'n laser beam on its head.

4 minutes ago, chrisl said:

The catch is that there's probably latent damage to at least the nearest bearings on the inner deck.  It got enough force to dent and crease it near the point of explosion, so some of that would have been transmitted.  It's now one of those roads that you take in a small car because you to make a trip and have no choice, but if they drive a bunch of heavy trucks loaded with tanks and ammo over it, it could have cracks that propagate and fail catastrophically.  Especially since it's in a saltwater environment and suffers things like winter and ice.  Water is terrible stuff, especially if it can freeze and thaw (which I'm sure you have more experience than you want with).

For sure.  Latent damage should be presumed and therefor corrective measures taken to get the bridge back into specifications.  This is not necessarily something Russia will do because it's highly disruptive and takes a great deal of time.

4 minutes ago, chrisl said:

The rail bridge is also suspect - it took the pressure wave broadside because it wasn't shadowed, so there could be some hidden cracks started (or expanded if they were already there).  On top of that it had many hours of burning fuel on the steel in multiple spots.  That's going to change the steel properties there, and if they just run trains at full speed over it like nothing happened, they could get a surprise later.

If they don't do something to reinforce the steel in the sections that got bathed in burning fuel, I think we can safely bet there will be a failure there sooner rather than later.  Steel doesn't like to be subjected to concentrated, prolonged heat measured in hundreds of degrees centigrade (I saw one range of burning diesel at between 900c and 1200c depending on environmental factors).

Steve

[FancyCat]

Saki airbase. The bridge bombing. the potential loss of Crimea. A big reason why Putin may not have wanted to mobilize, that we see clearly now, despite all the propaganda, the red lines, the rhetoric, the Russian people don't want to fight in Ukraine, and as much as the RU nats are frothing at the mouth right now, the Russian people, the good majority don't care about retaining the Donbas, or denazificating Ukraine (certainly not enough to die, and if death by a bullet is not worth it, neither is nuclear warfare), and I doubt enlistment or conscription is going to tick up due to this bridge bombing, so I'm going to suggest that Crimea will largely turn out the same, Russians won't care enough to die for Crimea, and one of the central tenets of the red line on Crimea, is that the loss of Crimea represents a threat to the Russian nation and people and that will motivate them to declare "full war" or nuclear weapons use" or etc. 

That is looking brittle. Maybe a threat to Putin's rule and life. (tho i doubt that as well)

 

Edited October 9, 2022 by FancyCat

[dan/california]

12 minutes ago, FancyCat said:

I have seen comments noting that Ukraine continues to overstep Russian red lines, with seemingly little pushback. Even if the bridge reopens without a issue, aside from all the symbolism and other effects mentioned, it leaves the Russian state walking away from prior comments on red lines. Note very little word by Putin and co warning of nuclear retaliation or other escalation for attacking the bridge. If it was a true red line, warnings would be louder. 

A victory still for Ukraine even if their goal had been to destroy Russian logistics, the red line has again shifted, if the bridge is attacked and destroyed in the future, Russian use of escalation is weakened, both Ukraine and the west will be encouraged by this to keep pushing Russia. 

I want to bring up the sentiments of this thread, in how Ukraine has managed to bit by bit, shift our thinking in how Ukraine will operate, what Ukraine's capabilities are, as well as how Russia has lost initiative in the sentiments of the thread, and reflect that in the same manner as how time and Ukraine is changing how we think, the world is having the same done to it, where the Russian reality is ending and the Ukrainian reality is coming into focus. 

I recall stances like suggesting Ukraine would be better served refraining from attacking Crimea, or the Crimean bridge, either for escalation reasons, for operational reasons, it would be better to utilize resources closer to the front, etc. In the same way, I recall worry about Ukraine targeting inside Russia, targeting Russian infrastructure, thinking of wider offensives, the list goes on, as time has gone on, Ukraine is step by step illustrating its ability and resolve, and is not only shifting Russia's red lines, but our own perception of Ukraine and Russia.

The reason why I bring this up, (considering its pretty obvious, our thinking of Ukraine is framed by what Ukraine does), is to emphasize a clear positive movement in favor of Ukraine obtaining "total victory", of Ukraine moving both operationally in a military sense, as well as mentally, to prep the world for a day where Ukraine takes over Crimea. 

I know, maybe I am just wrong. what does a car bomb (or missile. or underwater SOF team. or....boat) compare to invading a island? this car bomb could have cut the only supply line to Crimea. this supply line should not have had this occur, and its viability as a loss in the future has just skyrocketed. this should not have happened, Russia should be able to protect this vital line, and Ukraine's ability to target it, i think one could stay most of us considered impossible a few months ago. Just like Saki. Just like two offensive actions occurring simultaneously. Or a massive long term psyop to turn Kherson into a trap. 

With each succeeding action Ukraine undertakes to undermine Crimea's defenses, Russia is losing more and more of the red line, and the mental fear that it represents, that Russia needs to enforce if it wants to prevent the line being tested via the liberation of the island. 

Ukraine has spent the last two weeks crossing every red line it could find in order to keep them from becoming accepted assumptions. The attack on the Kherson pocket, the Kerch bridge, and the air base in Russia were all designed to break red lines before the they could become set assumptions in the diplomatic discourse. I am as sure as I can reasonably be with only open source information that they did this very intentionally to retain the freedom of action they need to win this war. 

i suspect they hit the Kerch bridge before they had as many munitions as they would like for just this reason. Although it is also possible they just wanted to see how the bridge reacted to one or two missiles before used they used five or ten more of something they may not have very many of. A new attack in a week or less would indicate the latter, if it is a month or moreI really think it is the former.

 

[Battlefront.com]

30 minutes ago, FancyCat said:

I recall stances like suggesting Ukraine would be better served refraining from attacking Crimea, or the Crimean bridge, either for escalation reasons, for operational reasons, it would be better to utilize resources closer to the front, etc. In the same way, I recall worry about Ukraine targeting inside Russia, targeting Russian infrastructure, thinking of wider offensives, the list goes on, as time has gone on, Ukraine is step by step illustrating its ability and resolve, and is not only shifting Russia's red lines, but our own perception of Ukraine and Russia.

The reason why I bring this up, (considering its pretty obvious, our thinking of Ukraine is framed by what Ukraine does), is to emphasize a clear positive movement in favor of Ukraine obtaining "total victory", of Ukraine moving both operationally in a military sense, as well as mentally, to prep the world for a day where Ukraine takes over Crimea. 

This misses the point.  Putin, or his even worse successors, likely have some sort of red line.  Blowing up the Grand Kremlin Palace, for example.  The thing is we don't know where that line is or what the response will be when it is crossed.  Those of us (me included) that think Ukraine needs to take possible red lines into account when it plans its actions isn't defeatist, it's smart.  Very smart.  The trick of it is to correctly guess where the line is and then stop just short of crossing it.

The other point missed here is that surrounding conditions for X attack may matter.  The concept of "boiling the frog" is all about moving things along incrementally and complicating the other side's decisions about what is and isn't a red line and what should or shouldn't be the response.  Public opinion, capacity to respond, stakes for not responding, etc. probably change over time.  What might have been a clear red line crossing 6 months ago, accompanied by a massive response, might not illicit much of anything today because of this.  Ukraine and NATO have been doing an excellent job of incrementally making Russia's life worse. 

Lastly, it seems dumb to force an issue that could cross a red line when the issue can be resolved some other way.  Especially when there are more immediate things to concentrate on.  Collapsing Russia's military and/or political system will produce all kinds of new opportunities.  Therefore, don't invest anything into invading Crimea or even the rest of Donetsk, instead put it towards collapsing Russia's ability to keep the war going.  Hitting the Kerch bridge is about logistics first, PR damage second, and invading Crimea not at all (at least in the near future) so that is in keeping with this concept.

30 minutes ago, FancyCat said:

I know, maybe I am just wrong. what does a car bomb (or missile. or underwater SOF team. or....boat) compare to invading a island?

Russia still has 100% of Crimean land under its control.  Even a complete collapse of the bridge still means 100% control of Crimean land.  The same is true for the attacks against targets in Belgorod; Russia has lost 0% of its territory.  Even minor cross border incursions by ground forces are in the same category because nobody believes Ukraine is going to strike out to take and hold Belgorod with ground forces.

As soon as Ukraine's regular military force attempts to cross into Crimea, the assumption will be that they intend on keeping whatever they capture.  That's an entirely different concept for Russia to deal with.

30 minutes ago, FancyCat said:

With each succeeding action Ukraine undertakes to undermine Crimea's defenses, Russia is losing more and more of the red line, and the mental fear that it represents, that Russia needs to enforce if it wants to prevent the line being tested via the liberation of the island. 

Sure, and that's the result of a slow and steady strategy.

Steve

[FancyCat]

3 minutes ago, Battlefront.com said:

This misses the point.  Putin, or his even worse successors, likely have some sort of red line.  Blowing up the Grand Kremlin Palace, for example.  The thing is we don't know where that line is or what the response will be when it is crossed.  Those of us (me included) that think Ukraine needs to take possible red lines into account when it plans its actions isn't defeatist, it's smart. 

If I implied in "referencing the past" was to point out a past stances that became incorrect, my apologies I wasn't and did not intend that, and I don't think there is anything wrong in what was considered in the past. It was only to marvel at how Ukraine has done well (what you just stated, I agree with all of it entirely), how Russia's aura has dimmed, and ponder about how the course of the war will go with this trend.

 

[dan/california]

27 minutes ago, Battlefront.com said:

Russia still has 100% of Crimean land under its control.  Even a complete collapse of the bridge still means 100% control of Crimean land.  The same is true for the attacks against targets in Belgorod.  Even minor cross border incursions by ground forces are in the same category because nobody believes Ukraine is going to strike out to take and hold Belgorod with ground forces.

As soon as Ukraine's regular military force attempts to cross into Crimea, the assumption will be that they intend on keeping whatever they capture.  That's an entirely different concept for Russia to deal with.

Except that Crimea is completely unviable in even the medium term without the bridge, and the Crimean canal to supply water, On current form Russia will be evicted from in Nova Khahovka, where the canal originates, by Christmas. They might not be there next week. And by not viable I mean an economic millstone chained to Russias neck that it couldn't carry before this war, much less after it. And while I realize I am about to make a legalistic argument about an issue that is going to be settled by force of arms, the annexation of the four Oblasts completely obliterated the idea that Crimea is special, at least on paper.

Edit: And if Putin's back up plan was treaty that gives him Crimea, and a guaranteed water supply he should have avoided committing an endless list or warcrimes and atrocities that makes any deal with him whatsoever political suicide in Ukraine. Not convincing the whole world that every word he speaks is a lie would have been helpful with that, too.

Edited October 9, 2022 by dan/california

[JonS]

1 hour ago, chrisl said:

Especially since it's in a saltwater environment

It's a pretty new bridge though (4 years old? 5?), so I wouldn't expect to much pre-exisiting corrosion or damage. On the other hand, that spot on all three spans is probably going to suffer accelerated degradation from now on. Not fast enough to cause a corrosion failure this year - or next - but it'll certainly have lost a decent chunk of it's expected lifespan.

[LongLeftFlank]

2 hours ago, FancyCat said:

I have seen comments noting that Ukraine continues to overstep Russian red lines, with seemingly little pushback. Even if the bridge reopens without a issue, aside from all the symbolism and other effects mentioned, it leaves the Russian state walking away from prior comments on red lines. Note very little word by Putin and co warning of nuclear retaliation or other escalation for attacking the bridge. If it was a true red line, warnings would be louder. 

A victory still for Ukraine even if their goal had been to destroy Russian logistics, the red line has again shifted, if the bridge is attacked and destroyed in the future, Russian use of escalation is weakened, both Ukraine and the west will be encouraged by this to keep pushing Russia. 

I want to bring up the sentiments of this thread, in how Ukraine has managed to bit by bit, shift our thinking in how Ukraine will operate, what Ukraine's capabilities are, as well as how Russia has lost initiative in the sentiments of the thread, and reflect that in the same manner as how time and Ukraine is changing how we think, the world is having the same done to it, where the Russian reality is ending and the Ukrainian reality is coming into focus. 

I recall stances like suggesting Ukraine would be better served refraining from attacking Crimea, or the Crimean bridge, either for escalation reasons, for operational reasons, it would be better to utilize resources closer to the front, etc. In the same way, I recall worry about Ukraine targeting inside Russia, targeting Russian infrastructure, thinking of wider offensives, the list goes on, as time has gone on, Ukraine is step by step illustrating its ability and resolve, and is not only shifting Russia's red lines, but our own perception of Ukraine and Russia.

The reason why I bring this up, (considering its pretty obvious, our thinking of Ukraine is framed by what Ukraine does), is to emphasize a clear positive movement in favor of Ukraine obtaining "total victory", of Ukraine moving both operationally in a military sense, as well as mentally, to prep the world for a day where Ukraine takes over Crimea. 

I know, maybe I am just wrong. what does a car bomb (or missile. or underwater SOF team. or....boat) compare to invading a island? this car bomb could have cut the only supply line to Crimea. this supply line should not have had this occur, and its viability as a loss in the future has just skyrocketed. this should not have happened, Russia should be able to protect this vital line, and Ukraine's ability to target it, i think one could stay most of us considered impossible a few months ago. Just like Saki. Just like two offensive actions occurring simultaneously. Or a massive long term psyop to turn Kherson into a trap. 

With each succeeding action Ukraine undertakes to undermine Crimea's defenses, Russia is losing more and more of the red line, and the mental fear that it represents, that Russia needs to enforce if it wants to prevent the line being tested via the liberation of the island. 

Exactly!  This is vastly better analysis than Kofman's anxious 'oh, don't provoke the Russians or they'll get *really angry*' hand-wringing.

...Like the kids who once bullied him, they're totally inside his head. They own him. Meanwhile the Ukies are inside Moscow's, more every week, totally undercutting the bully's sense of superiority. And eventually, he starts avoiding them, seeking easier prey.

...I don't always agree with you on here mate, but I sense playing cards with you would get quite expens ive.

[duplicate quote bubble, I can't get rid of it so gonna repurpose it, it isn't an actual FC quote....]

2 hours ago, FancyCat said:

(using this spare quote bubble)

 

Edited October 9, 2022 by LongLeftFlank

[Zeleban]

Footage of the destruction of the BMP. Surprisingly, they held out for a long time under fire.

[TOG]

5 hours ago, chrisl said:

That road is probably pretty floppy when you're driving it with the kind of energy a point explosion of a truck bomb (or bigass missile, for Steve) would put in. It's going to both ripple longitudinally and have twisting modes.  It could walk/bounce itself off to the side a little and then tumble to get the amount of offset that's there.  It also looks like the longitudinal beams sit on small pier blocks on top of the big piers, so it would be tipping off those to one side and could have had enough momentum to tumble as much as it did.

We can see the explosion happened at the span of one of bridge segment - there are scorch Marks and blown out railings on the inner pane of Road bridge around that place. Explosive downward force snapped the bridge pane at the span, and that resulted in snapping the span on two adjanced support (the bridge seems to be a series of continuous beams - probably four spans each). The fallen span in the back (the one further away) was probably pulled from support longitudally by the span that fell under the explosion. The same applies to the span on the other end of continuous beam (next to exploded one). 

As for slipping to the side - when the pane broke in the exploded span and next span was pulled from the suport, it broke and bent upwards on the support between those two fallen spans, no longer lying on two bearings. I thing it does not need big additional side force to slip to the side. The both fallen spans probably touch the bottom of the sea and the upward part on top of the support started to fall to the side but got hanged on outside bearing.

[MikeyD]

Someone, probably on this thread ages go, quipped that anyone can build a bridge that stays up but only an engineer can build a bridge that barely stays up. 

Edited October 9, 2022 by MikeyD

[Zeleban]

14 minutes ago, MikeyD said:

Someone, probably on this thread ages go, quipped that anyone can build a bridge that stays up but only an engineer can build a bridge that barely stays up. 

By the way, Russian propagandists claimed that this bridge was able to withstand a nuclear strike.

[Tenses]

12 minutes ago, Zeleban said:

By the way, Russian propagandists claimed that this bridge was able to withstand a nuclear strike.

Yeah, just like their T-14 Armata 

[LongLeftFlank]

On 4/23/2022 at 5:31 AM, Combatintman said:

Dovhenke is certainly useful if you want to motor down the main road into Slovyansk but indirectly.  It sits in dead ground to that road so direct fires onto it are not possible but I see this as either an operation to secure the flanks for anything rolling down the road by denying a safe haven for shoot and scoot ATGM equipped parties or potentially using a covered approach to get into the wooded feature east of the village which does offer LOS onto the road.  That then serves as a jumping off point to clear the woods SE and east.

This area of ground leapt out at me early on when I was doing the terrain analysis as either a potential Named Area of Interest (NAI) or a Target Area of Interest (TAI).  It is not a bad Engagement Area (EA) and sits between a battalion and company-sized defensive position.  If resources permit, the Ukrainians could bottle that road up comfortably with a battalion (see diagrams) and if resources are tighter, it is possibly doable with a company, particularly if supported by a reasonably swept up obstacle plan with some gunnery on priority call.  My instinct for the latter option would be to position the company where the southernmost company astride the road is located in the battalion laydown.

 

ChrisO has just published a lengthy thread on the crucial battles for Dovhenke, the stubborn 'cork in the bottle' that from Apr - Aug stymied all Russian attempts to advance from Izium and take Sloviansk-Kramatorsk from the north.

With no major rivers and (seemingly) good tank country, this direction was Russia's best chance to secure the northern Donbass and perhaps Dnepro as well, before the Western long range guns and HIMARS came in strength and altered the game. 

Dovhenke should definitely be the subject of a future CM campaign series!

@Combatintman's synthesis from April. Dovhenke is that green patch just to the west of arrow AA2, about a quarter way along.

P.S.  It has its own Wikipedia entry now.

Edited October 9, 2022 by LongLeftFlank

[Kinophile]

Before I moved into film I was an architect.  One early lesson in structure in Uni for me was that the basic physical mechanics you see in a simple tabletop scale model of wood,, glue & card are very similar to the actual structural reactions in RL. 

In First year We modeled various structures,  incl bridges and subjected them to various dynamic forces and loads.  The earthquake tests were really fun, Esp on tall structures. We did tests where we deliberately failed parts of lollipop stick towers at upper levels,, then watched multiple floors pancake down, accelerating as they went. No fire,  no explosions, just simple sheer for e cutting through the structural connections, piling impact on impact, overwhelming the lower structure. 

Then A few days into my second year, I'm in the Student hall watching the Twin Towers pancake down in the exact same manner. I heard many people around me being shocked why the flattening of the towers was happening so fast,  but I intuitively understood,  even then in the middle of that horror. Nothing special about me,  just that those early modelling classes were critical learning moments in understanding why certain visuals of catastrophic failure look the way they do, and can be misconstrued from simple lack of exposure to physical realities. 

Relevant to the bridge here,  another a-ha moment for me was learning that a massive,  hundred+ ton steel&concrete span can literally bounce meters vertically -  just like a wood plank across two supports will flex and bounce off those supports.  The physics doesn't change,  just the scale. 

Something for me still doesn't ring true about a truck bomb. @chrisls note about the span probably bouncing/rippling and flexing enough to sheer/pop off its pins to the supports does make sense and correlates with my learning and prior experience.

To go back to Steve's note about missing information that will clarify,  Quality of construction and the inherent trade offs in any design are critical to understanding structural failure, and why the bridge failed in the manner it has,  exposed to the forces that it was.

We have a lot of info,  but there's something still missing. 

 

[dan/california]

19 minutes ago, Kinophile said:

Before I moved into film I was an architect.  One early lesson in structure in Uni for me was that the basic physical mechanics you see in a simple tabletop scale model of wood,, glue & card are very similar to the actual structural reactions in RL. 

In First year We modeled various structures,  incl bridges and subjected them to various dynamic forces and loads.  The earthquake tests were really fun, Esp on tall structures. We did tests where we deliberately failed parts of lollipop stick towers at upper levels,, then watched multiple floors pancake down, accelerating as they went. No fire,  no explosions, just simple sheer for e cutting through the structural connections, piling impact on impact, overwhelming the lower structure. 

Then A few days into my second year, I'm in the Student hall watching the Twin Towers pancake down in the exact same manner. I heard many people around me being shocked why the flattening of the towers was happening so fast,  but I intuitively understood,  even then in the middle of that horror. Nothing special about me,  just that those early modelling classes were critical learning moments in understanding why certain visuals of catastrophic failure look the way they do, and can be misconstrued from simple lack of exposure to physical realities. 

Relevant to the bridge here,  another a-ha moment for me was learning that a massive,  hundred+ ton steel&concrete span can literally bounce meters vertically -  just like a wood plank across two supports will flex and bounce off those supports.  The physics doesn't change,  just the scale. 

Something for me still doesn't ring true about a truck bomb. @chrisls note about the span probably bouncing/rippling and flexing enough to sheer/pop off its pins to the supports does make sense and correlates with my learning and prior experience.

To go back to Steve's note about missing information that will clarify,  Quality of construction and the inherent trade offs in any design are critical to understanding structural failure, and why the bridge failed in the manner it has,  exposed to the forces that it was.

We have a lot of info,  but there's something still missing. 

 

The Russians know what knocked it down. They probably knew in fours hours. The Ukrainians know exactly what they did it with. If was a missile(s) there will be another strike soon. If it was a special ops operation, probably not. Putin will probaly only shoot a few people for the first truck bomb, indeed it sounds like they are going to scapegoat some people whether or not there was actually a truck bomb. But if there is a second, for that first, REAL truck bomb the entire guard force would be headed to front line with Mosin Nagants with orders to charge thru a minefield, at a minimum.

[chrisl]

I've just been mentally factoring in that it's unlikely to built to anything like the standards I'm used to seeing in SoCal.  Probably designed with lower factors of safety than we'd see here, underconstrained against earthquake motion, and then contractors skimping on parts and materials, particularly in spots that don't normally have loads on them but are intended to accommodate conditions that are possible during the bridge's lifetime, but rare enough that it won't just fall on its own.  A big bomb on the road deck is one of those conditions that's outside the design space, but maybe would have been partly mitigated by good seismic design.

[chrisl]

3 minutes ago, dan/california said:

The Russians know what knocked it down. They probably knew in fours hours. The Ukrainians know exactly what they did it with. If was a missile(s) there will be another strike soon. If it was a special ops operation, probably not. Putin will probaly only shoot a few people for the first truck bomb, indeed it sounds like they are going to scapegoat some people whether or not there was actually a truck bomb. But if there is a second, for that first, REAL truck bomb the entire guard force would be headed to front line with Mosin Nagants with orders to charge thru a minefield, at a minimum.

And if they think it's a truck bomb, the inspections they'll have to do for rail and truck cargo to avoid a second one will be like TSA checkpoints from hell.

[dan/california]

4 minutes ago, chrisl said:

I've just been mentally factoring in that it's unlikely to built to anything like the standards I'm used to seeing in SoCal.  Probably designed with lower factors of safety than we'd see here, underconstrained against earthquake motion, and then contractors skimping on parts and materials, particularly in spots that don't normally have loads on them but are intended to accommodate conditions that are possible during the bridge's lifetime, but rare enough that it won't just fall on its own.  A big bomb on the road deck is one of those conditions that's outside the design space, but maybe would have been partly mitigated by good seismic design.

It isn't terribly relevant to the war but I think we have excellent evidence the bridge would not do well in even a medium sized earthquake. Unless we happened to get one right there, which would pretty much be god picking a side.

[Haiduk]

Second mass missile strike on Zaporizhzhia for last two days. During theese strikes dozens private and modular building destroyed and damaged. 29 citizens killed. more than 70 wounded and probably this is not final result. Reportedly in first strike Russians use S-300 missiles, which hard to intercept, in the second time about sozen missiles were launched from jets (Kh-59 or even Kh-22) 

 

 

Edited October 9, 2022 by Haiduk

[LongLeftFlank]

1 hour ago, dan/california said:

It isn't terribly relevant to the war but I think we have excellent evidence the bridge would not do well in even a medium sized earthquake. Unless we happened to get one right there, which would pretty much be god picking a side.

If Gawd won't do the smiting, do your own....

Can some kind of bunker buster or daisy cutter be delivered to the foot of one of those piers (any pier will do actually, doesn't have to be these)?

Bielefeld Viaduct after Barnes Wallis' 'Grand Slam' earthquake bombs came to visit....

Also, the Russkis have been tossing around thermobaric rounds like candy in this war. Maybe aim a few along the roadway and see what the lateral overpressures do to the RR bridge and those nice tall (and possibly mob-substandard) piers....

Edited October 9, 2022 by LongLeftFlank

[Beleg85]

40 minutes ago, Haiduk said:

Second mass missile strike on Zaporizhzhia for last two days. During theese strikes dozens private and modular building destroyed and damaged. 29 citizens killed. more than 70 wounded and probably this is not final result. Reportedly in first strike Russians use S-300 missiles, which hard to intercept, in the second time about sozen missiles were launched from jets (Kh-59 or even Kh-22) 

Russians are habitually targeting civilians Zaporizhzhia now just like they did with Kharkiv. They also constantly try to attack Odessa for some reason. It is troubling we get accustomed to such events of mass casualties; at the start of the war it would be in all news.

Here is interesting short thread about Surovikin (in pl, but autotranslate works well):

To sum up: new (first?) general commander on Ukrainian front is civilians killer who personally (!) shed blood in Moscow in 1991, corrupted officer who allowed diedovshchina to spread in his units, rather unsuccessfull commander and - interesting fact- another friend of Don Don Kadyrov. The last one is only thing that make him different from crowd of Russian high officer corps.

Edited October 9, 2022 by Beleg85