SteveR wrote:
And yet the ship stopped right on the spot of impact. If things were as dire as you insist, why didn't it just keep moving THROUGH the bridge onto the other side of it? Solid rock has a way of stopping even the stoutest of vessels.
Going by aerial photos posted of the scene, it appears the Dali moved forward about the width of the four lane bridge after making contact. That is how much force was still being applied by that mass at about a fast jogging speed/slow running speed. What kind of barrier should be erected so that there is no chance of bridge damage from a heavy mass of that kind at a higher speed?
The mass of the below water bridge structure was able to catch that.......
maybe. The draft, or draught if you prefer, of the Dali is reported at 49+ feet. It's reported the bottom where much of the bridge wreckage is lying, is around 50 feet.
Over there, out to the side of the main channel, outside the bouy markers, is the keel of that ship on the bottom, in shallower water? Did that also exert stopping force against its forward movement, so that the underwater bridge structure did not bear all the pressure that could have been applied, had the bottom been much, much deeper than the draft depth of the vessel?
Is the ship in contact with the bottom now, helping to keep it stable where it is?
All questions that hopefully can be answered in public reports as the investigation moves forward.
My points:
•• this was a very high mass, low speed incident, and is it yet known that the ground, bottom of the harbor, did not have any part in stopping the forward movement of that ship?
•• how much mass/size/rigidity of bumper/pylon/dolphin/barrier/protector is going to be required to ensure there will never be any instance in which any impact will be too much for the capability of the baririer.
•• where do engineers, regulators, financiers, builders, upset public, finally agree to draw the line that there is enough barrier to prevent any remote possibility of ever having anything break through, ride over, disintegrate into multiple battering rams and pummel the bridge support from different moment force points and still wreck the bridge support, instead of holding together in one single, slow ram as happened this time?
•• How far out from the bridge support should the outside edge of the barrier be located, so that any large, massive vessel whose farthest forward upper edge is many yards forward of its hull at waterline, has less than zero chance of ever contacting the bridge support, in any scale of disaster?