Note | the whole assembly seems to be mostly held together by the ships parked in the drydock - the friction of the keel on the floating devices seems to be the main force that holds the assembly togehter …
In the case of a street on the water the plate on top will definitly create a by far better and stronger connection… so things will be on the “safe side”
The fact that this dock (uss Artisan) had 10 segments A-J and they could be installed and handled seperatly indicates that the connection between those segments was "very weak "
and certainly not “structural” nor was there any connection between the segments below the water surface.
So the principle of "underpinning with no big deal structural connection - let go 40 m bridging - has historic precedents that worked very well …
AFDB were needed to repair battleships, aircraft carriers, cruisers, and large auxiliary ships. AFDB-1 Artisan had 10 sections (A to J) for a total lift of 100,000 tons and was 1,000 feet long with all 10 sections installed…
So in the underpin the street design we repeate what was done in ww2 ship repair adding safety by connecting the rebar … and adding service life by doing that in concrete.
We do certainly not touched “never tested engineering” territory with that, and will not have to “reinvent the wheel” either.
Doing what “has been done before” and “add safety to the baseline” is certainly good engineering.
Obviously those engineers that came before did not include the postulate of 40m bridging into their design…
They counted with “uniform bouyancy support” instead as something that goes into the base equation of “tough enough”
The allied forces had duzends of those modular drydocks and no accident of segments being moved from their position during the docking process was reported -
I would postulate the “underpin with boyancy force and friction” works very well in marine practice. I would not have sleepless nights over it.
If you think it trough, the calculation of a land street, where you have no calculable buoyancy force, and need to work with “clay soil that creeps out under your street” all the time, seems to be “much more nightmarish” in comparsion.
What we know by now is, that what the ocean brings up on forces against such a construction, will be “well and safe” negociated by bouyancy and friction allone…
Needless to say that those docks where installed in the US hurricane zone, and a couple of them for sure must have met hurricanes ( no total loss was reported ).
Although that is stuff as you do it in wartime engineering not in civil engineering…
Fact is | they did it | and the data are in | and the data looks favorable…