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From: "Carlos E.R." <robin_listas@es.invalid>
Newsgroups: sci.electronics.design
Subject: Re: Full video of ship hitting and destroying the Francis Scott Key
 bridge in Baltimore
Date: Sun, 31 Mar 2024 23:19:04 +0200
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On 2024-03-31 01:47, bud-- wrote:
> On 3/30/2024 12:05 PM, Carlos E. R. wrote:
>> On 2024-03-29 16:21, bud-- wrote:
>>> On 3/29/2024 5:18 AM, Martin Brown wrote:
>>>> On 29/03/2024 06:06, UFO wrote:
>>>>>
>>>>> Out of all the hours it sailed in operation, maintenance checks 
>>>>> were all fine
>>>>> then out of the blue not 1 but 3 power failures, and not out in the 
>>>>> middle of the ocean
>>>>> from harms way...just close enough to a bridge and hit the weakest 
>>>>> spot. What a
>>>>> "fluke"
>>>>
>>>> Hardly. Murphy's law can apply IRL. Dirty fuel seems quite plausible.
>>>>
>>>> The bridge was *designed* to fail catastrophically if anything hit 
>>>> one of its main supports which is unforgivable on a bridge that is 
>>>> over a waterway leading to one of the busiest Atlantic ports in 
>>>> America.
>>>
>>> Bridges would not similarly fail when you take out a pier for a major 
>>> span?
>>
>> On some bridges, only the spans directly supported by that pier fall, 
>> not all.
>>
> 
> So main span falls and on the other side of the pier that did not fail 
> the approach stays intact? Falling main span does not affect pier?

Depends on the design.

I can not tell you what they do, only that I read or heard comments from 
"experts" saying so.

> 
>>>
>>>>
>>>> Most big bridges in first world countries have buffer islands and 
>>>> underwater structures to deflect and/or slow a large vessel to 
>>>> prevent them from impacting any of the key support structures near a 
>>>> live shipping channel. The ship may ground and be damaged and the 
>>>> bridge shaken by that impact but that should be about the limit of 
>>>> what can happen to a properly designed bridge in these circumstances.
>>>
>>> The United States Secretary of Transportation (Buttigieg) has said he 
>>> doesn't know of any bridge that could withstand a similar hit. Hard 
>>> to imagine how you could protect from the energy in such a massive ship.
>>
>> With a massive island, but that reduces the passage for ships, which 
>> then have more chances to crashing into it, and impairs traffic.
>>
> 
> So island is anchored and constructed so a hit from a massive container 
> ship won't destroy it or tip it (how far down does it go)?. And has to 
> be bigger than how far into the island the ship penetrates plus how far 
> the bow sticks out plus how far the bow dents in? Plus the pier can 
> survive the shock (like earthquake proof)? Where does the energy go?

Heat, and metal crushing :-)

Yeah, the island has to be massive, which is a problem for traffic.

> 
> Requiring tugs to accompany large ships may be more practical. One may 
> assume that wasn't required here. Bow thrusters probably make 
> maneuvering ships in a harbor without a tug practical.

Yep.

-- 
Cheers, Carlos.