I am a civil engineer with experience in concrete design.

[flashman13]

While the video quality isn't the best, I have been studying a fairly decent one of the railroad bridge in profile. There is a place where there was a very hot fire directly over one of the piers right at the joint of two bridge sections. I think, emphasizing less than great images, there appears to be structural damage at that point with some displacement downward. That bridge is concrete (cheaper than steel - go figure) made up of multiple longitudinal sections. Even if only the outer member is damaged, the bridge is compromised. At best they made a quickie inspection. I would not sign off on its usability without some serious testing.

In another video, a second set of pictures looking up at another pier, clearly shows, over a substantial area, that the outer layers of concrete has peeled off exposing the entire rebar grid. That's not a good sign. High heats can severely compromise concrete. Some of the earlier pictures show entire areas of the bridge ringed with flames. I would definitely advise that trains proceed very slowly over that entire damaged area.

Also, in another video, looking down the center line of the remaining road span, you can see that the outer edge of the structure has a large inward buckle. Depending whether other adjacent members are also buckled, that could be a sign of sever damage. More importantly, it appears that the bridge deck from which the picture was take has displaced vertically downward along its full width. I could be wrong here. Again the quality isn't great. But if there is that sort of significant displacement there is very serious damage which will significantly limit the usability of that span.

All in all, the bridges received significant damage. Someone got an extremely large bang for their buck. I don't believe a word of the truck bomb explosion theory. My guess is that it was a broadside hit from an anti-ship missile fired from a small boat. We already know the Ukrainians are very resourceful.

[Irish_Dem]

1. Yes the source of the bomb aligns with my thoughts as well.

Truck bombs are not the Ukrainian style.

They like to use missiles. And yes from a small boat, evading all Russian
defensive protections would be their style as well.

Thank you for the run down on the engineering end of things.
I was clueless about that piece.

How long would you estimate it would take the Russians to re-build?
Of course, battle conditions may not allow repair at this point.

[flashman13]

14. Unfortunately the Russians went el cheapo!

If the bridge was steel and not concrete it could be safely jury-rigged fairly quickly, days or maybe weeks with the Russians, with steel gusset plates and lots of bolts similar to what they did on the broken I40 bridge at Memphis. Concrete is a whole other story. It all depends on approach. I'm guessing that multiple members are cracked and severely weakened. The only real fix is replacement. Were the Russians smart enough to stockpile generic concrete sections for emergency repairs? If so, again depending on Russian capabilities, a couple of weeks. My guess is the top of the one pier is fairly damaged. I think a steel cap could be fashioned right on top of the pier in order to distribute the load. However, there would be some periods when trains could not cross. How long can the Russians stand that? They might be able to go to the quick fix. IF the bottom is shallow, I think they could jury-rig up temporary piers under the various damaged bridge members in order to shore them up. During WWII Russian sappers would already be building square wooden cribs up under the bridge. They would have had it done in a few days.

[Irish_Dem]

25. Yikes, replacement not repair. And they most likely don't have the materials necessary.

To answer the stockpile of concrete question:

It is not a question of Russian smarts.

It is a question of Russian corruption. No one is using a stockpile, so it gets stolen and sold.
But we don't even know if they went to the trouble of making a cement stockpile.

But they could temporarily rig something up to make the bridge operational?

And shore up the bridge defense system in the meantime.

Thank you for your answer and welcome to DU.

[Bernardo de La Paz]

2. I've seen video show cars driving through, but says there is a limit of 10 per half hour

Seem to be a single lane.

My guess is that they will run it for show for a little while and then shut it down for a few days to rebuild that section.

[COL Mustard]

12. Aaaand.....

Howjs like to be one of them drivers????????

[Bernardo de La Paz]

3. There is speculation it was a boat drone; consistent with roadway section lack of damage

It is claimed video shows the prow of a boat underneath before the explosion, but I think it is just a wave. However, lack of video evidence does not rule out a boat drone.

The three or four panels of road (two sections) don't show much down-force blast damage. But being deposited in the water mostly unbroken would be consistent with being lifted off of their pylons by an up-force blast.

It would take only one hot piece of metal shrapnel to set off a fuel tanker rail car.

I am sure simulations are being run in multiple locations worldwide as we type.

[flashman13]

8. I don't think it was a boat drone.

The explosion pattern is not consistent with an explosion from below. The impact had to be horizontal and virtually at the top of the side of the destroyed bridge section in such a way that the exploding shrapnel could have cleared the deck and flown upwards and side wards toward the rail bridge and train cars. A truly spectacular shot with perfect timing on the train. I really believe that the attack was fired manually by a live observer in a boat standing off some distance.

[PortTack]

11. The Ukrainians manufacturer the Neptune missile, the missile used to sink the Moskva

[Lithos]

22. You do not need a person on premise to do this

A drone and a good unmanned "torpedo" boat (I am forcing a historical analogy - I realize it's not correct, but gives the idea) could accomplish the timing portion. A small unmanned Kayak boat obtained from existing US Naval stores washed up outside Sevastopol end of September. Makes me wonder what else they would/could have gotten.

But I think it is more likely that it was either a plane launched Harpoon missile and/or Ukraine Navy SEALS who mined the bridge and used a drone to time when to set it off.

[Lochloosa]

4. Have you seen this video?

[flashman13]

5. I have seen the video.

The length of the view is very foreshortened. The explosion occurs between the forward truck and the car. There seems to a hint that the explosion originates on the right side.

[dembotoz]

6. The times reports a 15 car train has crossed the bridge

so at least limited reopening i guess.

hope the crew of the first train got paid lots.

wonder how long before they get reckless and try full service.

safety is not high on putins list

[Lithos]

23. Metal fatigue can take time

So, the open question is - how many times and at what load?

[NullTuples]

24. "I would not sign off on its usability without some serious testing"

Perhaps Putin's Generals decide to test in production, so to speak...

[erronis]

7. Most of our major highways are extremely vulnerable to well-timed rockets fired at fuel trucks.

While this blast seemed to originate below the road surface in the video, it may have come from a lower level road. However the video seems to show a violent blast near the surface, not from below.

It doesn't take much to disable a huge amount of traffic. Fuel carriers when hit by an incendiary round could easily take out a large section of roadway for many days. I've been in Wash DC and witnessed several major disruptions - not caused by enemy actions. Just imagine...

The capabilities of the US supplied shoulder-launched weapons used in UKR can be used everywhere in the world.

[flashman13]

9. It was an hell of an explosion.

In my opinion, only for what its worth; but to create such damage with a single shot would be consistent with an anti-ship missile. If you note, a large number of tankers all show significant side damage. The shrapnel fanned out over a large area.

[sir pball]

27. Fuel trucks don't explode, they just burn.

Sure, you get a giant theatrical fireball of flaming gas, but there's no actual detonation with a damaging shock wave (unless the truck us empty and you get a fuel-air explosion, but that would be very random). The resultant fire can absolutely weaken or destroy the bridge, see 9/11, but it's not like the movies where a tanker truck of gas is the equivalent of a MOAB.

I don't think this was even a missile, they only carry a few hundred pounds of explosive - in my armchair estimate it was at least a thousand pounds of boom. Maybe not a truck bomb, but definitely more than a couple of rockets.

[AllyCat]

10. I've watched that video over and over.

That explosion came from under the bridge. I suspect it was timed for low traffic flow and a train hauling flammable material was next to it.

You are right: the Ukrainians are very resourceful.

[Qutzupalotl]

13. The sparks pattern after the explosion is consistent with a hit from the side or below

rather than a truck bomb. So I think you're right. Thanks for sharing your expertise.

[moondust]

15. Would Russia have more video?

These days wouldn't it be negligent to build a $3.6 billion bridge and not mount some security cameras to keep an eye on it? I mean, way back in February when the war started it occurred to me that Pooty's big bridge would make an easy target, and at that time I didn't even know it was being used as a supply route. Of course Russian propagandists could modify any camera footage and blame whomever.

[Shipwack]

31. Was money -allocated- for cameras? Probably yes.

Was that money actually spent -for- cameras?

[Gore1FL]

16. Thanks!

I was, frankly, shocked they cleared the railroad bridge of the train so quickly (unless they just pushed everything over the side). I am finding it hard to believe that maintenance-of-way crews could have the track in working order this fast.

I hope they keep hitting it.

[MLAA]

17. Thank you for the post. Always interesting to hear from subject matter experts on DU.

[PortTack]

18. Yes it is good to hear from an expert..thx flashman!

[DallasNE]

19. Likewise

I never once believed the truck bomb theory, just like the careless smoker claim 2-3 months ago. A truck bomb would have caused a different kind of damage. And there would have been scorch marks visible. Plus, a truck bomb would have blown off both guard rails where the bomb exploded. Lastly, it would seem to me that the train was pretty far away to to ignite the tank cars. My quibble would be that 2 missiles were used.

[DallasNE]

20. Likewise

I never once believed the truck bomb theory, just like the careless smoker claim 2-3 months ago. A truck bomb would have caused a different kind of damage. And there would have been scorch marks visible. Plus, a truck bomb would have blown off both guard rails where the bomb exploded. Lastly, it would seem to me that the train was pretty far away to to ignite the tank cars. My quibble would be that 2 missiles were used.

[Lithos]

21. First "job" was as a Mech Eng doing structural design (cranes, etc.)

Not quite up to the same expertise you have on this subject. But agree with what you are seeing. For myself, what gets me is the heat on the rails. Thermal expansion is such a huge problem in building tracks that lots of thought go into the design. Even bending caused by normal seasonal expansion can and does severely weaken other components (ties, etc.) and leads to track and train failures. I would not trust any of portion of the track for some distance before and after where the fire was until it gets replaced.

As for what caused it - was thinking of things other than a truck bomb or a HIMAR. Air-launched Harpoon, an unmanned Boat (one just washed up outside of Sevastopol a few weeks ago), or good old-fashioned ordnance laid by Ukraine SEALS seem a better answer.

[sir pball]

26. The R-360 Neptune Ukranian anti-ship missile only has a 330-lb warhead.

That's the same size as a Maverick missile and a single one of those will not take out a bridge. This boom was a *lot* more than 300lbs of explosive. I'm not saying it was a truck bomb, but it was definitely more than a missile – closer to a Mk83 1000-pound bomb, if not a Mk84 2000-lb (which is what we used to take out bridges in Vietnam).

[flashman13]

28. While a 300 lbs explosive is realatively small I wouldn't rule it out.

Everything I see suggests it was a horizontal attack which is not the signature of a vertical launch missile attack. It could have been a cruise missile, but I have seen no reports that the Ukes have them. We know they have anti-ship missiles, they have used them very effectively and they are very adept at modifying existing systems. I do think it would have taken a very large explosion to do that much damage in an open air detonation such as vertical missile. The derbies pattern would also look different. In that situation I would almost expect it to have blasted a few rail cars right off of the bridge. Also a vertical shot would have required extreme accuracy while a horizontal shot provides a much easier target. Having said that all that, I still think it was the perfect shot. It could have been a purely luck shot or very well aimed. What I see is a horizontal missile hitting the road bridge on the outside very near the top of the span with the initial explosion taking down the outside span (the bridge structurally does not look that substantial, similar to a ship side) and fiery debris and shrapnel exploding upward and forward cleanly missing the inner road bridge and spraying multiple rail cars, also of thin construction, puncturing multiple holes which burst into flames. The concussive force would probably be sufficient to cause some displacement of the inner road bridge.

The anti-ship missile is pure speculation on my part. I feel comfortable with that theory, but I admit it could have been some other device. I do stand by my horizontal attack theory.

[NNadir]

29. Thanks... n/t.

[Sneederbunk]

30. Remember the Smart Bombs? Doesn't Ukraine have an air force?

[honest.abe]

32. I agree with your comments. Looks like a missile from the right side.

From the videos you can see alot smoke and flashes from the right side which then rapidly pushed across to the other side and also appeared to extend up to the train rail area which probably ignited the fuel cars in the train.

[blue-wave]

33. I agree it was a missle

The Russians are claiming a truck bomb traveled a long circuitous route through many countries to get to the bridge. And some mainstream media repeats the Russian propaganda verbatim.

There is a missile that can be fired from HIMARS with a range of 190 miles. If the Ukrainians are in possession of this missile, it's possible to fire from some corners of free Ukraine. Although a missile mounted on a boat or ship is more plausible.

[orangecrush]

36. A wake up call for Putrid

Perhaps Ukraine giving a demonstration of some new goodies we sent them that he didn't know about, and a giant "FUCK YOU" response to Poot's nuclear threats.

[The_Casual_Observer]

34. Most likely it won't be the last time. Adding more security isn't going to

To help if rockets are used. Checkmate.

[orangecrush]

35. We're going to build a bridge

It will be a beautiful bridge, the best bridge in the world

Fuck your bridge.