<story><title>Baltimore&apos;s Key Bridge struck by cargo ship, collapses</title><url>https://www.wbaltv.com/article/baltimore-bridge-collapse-key-bridge/60303975</url></story><parent_chain><item><author>xoa</author><text>Just to put some numbers on this:&lt;p&gt;The MV Dali (IMO#9697428) is a little over 95000 GT, or ballpark-ish probably around 114000 tons loaded (and it seems to have been loaded, which would make sense on departure). If it was going even 5kn (2.6 m&amp;#x2F;s) that&amp;#x27;d be about 300 million newton-seconds, or about 3.3 times the momentum of a large jumbo jet like a 747 shortly at cruising speed (around 560 mph). It&amp;#x27;d still have the same momentum as said jet if it was going just 1.5kn. The ship of course is enormously more stoutly built and the force is going to be transmitted far more directly into whatever it hits vs into explosions driving mass elsewhere.&lt;p&gt;I&amp;#x27;ve read that both on water and in space for that matter enormously massive objects moving very slowly messes with human perception and &amp;quot;common sense&amp;quot;, it &amp;quot;feels like&amp;quot; something moving along smoothly and slowly should be stoppable or come to a stop. Enormous momentum and forces can be terrifying things.</text></item><item><author>dathinab</author><text>At least in the links with the video now you can see that the container ship directly hits one of the two main (and in the central area only) pillars completely collapsing it.&lt;p&gt;No matter(1) the engineering there is no pretty much way to not lose the whole large middle area and left area leading to the destroyed pillar in that situation.&lt;p&gt;Such a collapse crates so much force (tension vibrations etc.) so that the collapse of the section right of the right pillar is not unreasonable.&lt;p&gt;The only question is if the impact should have made the pillar collapse.&lt;p&gt;But a loaded container ship is ... absurdly massive I mean they are like multiple  high raise building (but not sky scrapers) standing squished together side by side. So the force it can apply is huge and if cargo moving in it there will be force applied to whatever it crashes into even after the initial impact.&lt;p&gt;And looking at the waves caused by impact with the base it was at least 8m high I think (depending on the container ship). So that wasn&amp;#x27;t a &amp;quot;slow moving&amp;quot; impact. And even slow moving impacts with container ships can tear apart a solid jetty.&lt;p&gt;So while the US has issues with infrastructure maintenance idk. if anything but building a many pillar bridge would have made any difference. And building a many pillar bridge might not be very viable depending on the under water landscape and water use under the main area.&lt;p&gt;EDIT: Looking at pictures with daylight where you can try to estimate the high of the ship using containers I would say the waves where handwavingly 4 containers high so ~9.5m and it also looks like the ship might have embedded half of the pillars fundament into&amp;#x2F;under itself (but it&amp;#x27;s a bit hard to tell to the angle of the picture). I think if that&amp;#x27;s the case probably the huge majority of bridge pillars of past and presence would have collapsed.</text></item><item><author>TaylorAlexander</author><text>Somehow I find it surprising how completely the bridge collapsed after the damage. I understand that a container ship collision is serious, but you could imagine a scenarios where the bridge slumps or buckles but doesn’t just disintegrate like that. It’s surprising that ships capable of doing this damage were probably regularly driving past it, and its safety as a thoroughfare depended entirely on those collisions not happening.&lt;p&gt;Does anyone know if modern construction standards would require more stability after a ship collision, or is this still how we build bridges?</text></item></parent_chain><comment><author>litenboll</author><text>I had a summer job once, filling trains with sugar. They weighed about 15kkg per wagon (usually 5-10 wagons per train IIRC).&lt;p&gt;One time the pulling cart broke down and we had to switch it for another, but when we took it off the rails we forgot about the &amp;quot;shoe&amp;quot; that is supposed to go between the rail and one of the wheels so it can&amp;#x27;t move downhill (it was like 1degree of slope so barely recognizable as a slope).&lt;p&gt;It started moving extremely slowly, and all of us except one tried to hold back the force of the train, which of course was imossible and dangerous. The one who did not try to push it very quickly found the &amp;quot;shoe&amp;quot; and put in place. Initially it did not seem to help at all, the train just continued moving at the same pace, tearing up asphalt with the shoe. It finally came to a stop after about 3-5m(?) which takes a fair bit of time with such low speed, and felt like forever given the situation.&lt;p&gt;The train tracks headed out into an open road, so it could have been so much worse if it were not for the only person thinking clearly in the situation (he was one of the more experienced in our group).</text></comment>
<story><title>Baltimore&apos;s Key Bridge struck by cargo ship, collapses</title><url>https://www.wbaltv.com/article/baltimore-bridge-collapse-key-bridge/60303975</url></story><parent_chain><item><author>xoa</author><text>Just to put some numbers on this:&lt;p&gt;The MV Dali (IMO#9697428) is a little over 95000 GT, or ballpark-ish probably around 114000 tons loaded (and it seems to have been loaded, which would make sense on departure). If it was going even 5kn (2.6 m&amp;#x2F;s) that&amp;#x27;d be about 300 million newton-seconds, or about 3.3 times the momentum of a large jumbo jet like a 747 shortly at cruising speed (around 560 mph). It&amp;#x27;d still have the same momentum as said jet if it was going just 1.5kn. The ship of course is enormously more stoutly built and the force is going to be transmitted far more directly into whatever it hits vs into explosions driving mass elsewhere.&lt;p&gt;I&amp;#x27;ve read that both on water and in space for that matter enormously massive objects moving very slowly messes with human perception and &amp;quot;common sense&amp;quot;, it &amp;quot;feels like&amp;quot; something moving along smoothly and slowly should be stoppable or come to a stop. Enormous momentum and forces can be terrifying things.</text></item><item><author>dathinab</author><text>At least in the links with the video now you can see that the container ship directly hits one of the two main (and in the central area only) pillars completely collapsing it.&lt;p&gt;No matter(1) the engineering there is no pretty much way to not lose the whole large middle area and left area leading to the destroyed pillar in that situation.&lt;p&gt;Such a collapse crates so much force (tension vibrations etc.) so that the collapse of the section right of the right pillar is not unreasonable.&lt;p&gt;The only question is if the impact should have made the pillar collapse.&lt;p&gt;But a loaded container ship is ... absurdly massive I mean they are like multiple  high raise building (but not sky scrapers) standing squished together side by side. So the force it can apply is huge and if cargo moving in it there will be force applied to whatever it crashes into even after the initial impact.&lt;p&gt;And looking at the waves caused by impact with the base it was at least 8m high I think (depending on the container ship). So that wasn&amp;#x27;t a &amp;quot;slow moving&amp;quot; impact. And even slow moving impacts with container ships can tear apart a solid jetty.&lt;p&gt;So while the US has issues with infrastructure maintenance idk. if anything but building a many pillar bridge would have made any difference. And building a many pillar bridge might not be very viable depending on the under water landscape and water use under the main area.&lt;p&gt;EDIT: Looking at pictures with daylight where you can try to estimate the high of the ship using containers I would say the waves where handwavingly 4 containers high so ~9.5m and it also looks like the ship might have embedded half of the pillars fundament into&amp;#x2F;under itself (but it&amp;#x27;s a bit hard to tell to the angle of the picture). I think if that&amp;#x27;s the case probably the huge majority of bridge pillars of past and presence would have collapsed.</text></item><item><author>TaylorAlexander</author><text>Somehow I find it surprising how completely the bridge collapsed after the damage. I understand that a container ship collision is serious, but you could imagine a scenarios where the bridge slumps or buckles but doesn’t just disintegrate like that. It’s surprising that ships capable of doing this damage were probably regularly driving past it, and its safety as a thoroughfare depended entirely on those collisions not happening.&lt;p&gt;Does anyone know if modern construction standards would require more stability after a ship collision, or is this still how we build bridges?</text></item></parent_chain><comment><author>KineticLensman</author><text>&amp;gt; enormously massive objects moving very slowly messes with human perception and &amp;quot;common sense&amp;quot;&lt;p&gt;Yes, hence warnings to amateur boat users (e.g. on a canal boat) not to try to stop a collision with the bank using your arms or legs.&lt;p&gt;[Edit] Boats can also do things that are unintuitive if you are used to driving a car. E.g. turning round the centre of gravity when you steer rather than following the front wheels.</text></comment>