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- Oct 25, 2021
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Okay.
At least 7 dead after a ferry landing dock gangway collapses at Sapelo Island, Georgia
- Thread starter y_p_w
- Start date
Swimming education and access may not have been available, when they were younger, to those who perished.
Also, there is swimming, and then there is being a older person swimming after completely unexpectedly you drop ~10 feet into apparently turbid water with a strong current, and possibly being injured by the fall.... Tragic and I am curious as to the actual failure.
Exactly…
You try to swim against even a 1 mph wind after current will tire a average swimming person… Fairly quickly.
You try to swim against a 4-5 mph water current… you will die EASILY. In my area College Creek near the Parkway people die trying to swim to a nearby sand bar. Problem is that water is hauling ass and they get tired fast and go under. A very sharp curve in the creek where the parkway crosses it comes and straightens out with incredible water speed. And if you are doing that on an out going tide on top of that. . Exceptionally dangerous then.
I saw Powatan Creek when I was fishing a few months ago after heavy rains… Another tidal creek that flows out into the James River. And let me tell you that debris was FLYING by my location that afternoon. Out going tide too. If the I had tried to swim across that 60 to 70 foot creek I would have been in massive trouble.
Some more. Originally I said 20 on the gangway, it was probably more. It was 20 who fell into the water. There was video of it around the time of the collapse and there were quite a few people trying to hold on to the railing.
I've been on a variety of ferries. Usually there's dock and I don't think I've ever been on a gangway this long. Most gangways I've been on are shorter ones that are rotated into place. I'd also been on one ferry in Asia where they didn't seem to have a whole lot of worries about safety as I actually needed to jump slightly over a slight gap between the dock and the ferry without a short gangway.
DNR Commissioner Walter Rabon said Sunday that “catastrophic failure” caused the collapse. An estimated 20 people fell into the water and as many as 40 could have been on the gangway at the time.
However, the agency later reported that an engineering firm had concluded the structure should have been capable of safely supporting the equivalent of 320 evenly distributed individuals averaging 200 pounds in weight.
Based on the size and specifications of the gangway, Fritz calculated that it should have had the capacity to hold 240 people at that weight "without even including any additional safety factors.”
“Any reasonable gangway operation would (be required) to have at least one full passenger load on the gangway or two boatloads if boarding and deboarding are not strictly separated,” added Fritz, whose research focuses on the impact of natural disasters including hurricanes, tsunamis, earthquakes and landslides.
I've been on a variety of ferries. Usually there's dock and I don't think I've ever been on a gangway this long. Most gangways I've been on are shorter ones that are rotated into place. I'd also been on one ferry in Asia where they didn't seem to have a whole lot of worries about safety as I actually needed to jump slightly over a slight gap between the dock and the ferry without a short gangway.
Well that’s good to know. ….i guess?
There were 13 or more survivors in this accident. I’ll say fellow swimmers I assume.
I spent some time as a forensic engineer so I usually read about these types of disasters out of curiosity.
Based on some reading and investigation I’ve done based on photos it appears that the cause may be due to a 60ft section of this pre-engineered span simply being welded to another pre-engineered 20ft section for the 80ft span and it may have failed at the weld location. Possibly a welding failure and/or modifications to a pre-engineered design it was never designed for. You can’t take a 60ft span and just weld another 20ft span onto it. The top chords and other structural elements need to be designed for the increased span and stresses. The minute they (specutively) welded on another 20ft section that engineers design calculations went out the window.
I see this all too often in my field - who needs an engineer to design or review this!? They’ll just increase cost and “overbuild it.” I can do it cheaper!
https://www.eng-tips.com/viewthread.cfm?qid=523612
Based on some reading and investigation I’ve done based on photos it appears that the cause may be due to a 60ft section of this pre-engineered span simply being welded to another pre-engineered 20ft section for the 80ft span and it may have failed at the weld location. Possibly a welding failure and/or modifications to a pre-engineered design it was never designed for. You can’t take a 60ft span and just weld another 20ft span onto it. The top chords and other structural elements need to be designed for the increased span and stresses. The minute they (specutively) welded on another 20ft section that engineers design calculations went out the window.
I see this all too often in my field - who needs an engineer to design or review this!? They’ll just increase cost and “overbuild it.” I can do it cheaper!
https://www.eng-tips.com/viewthread.cfm?qid=523612
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