Post by D A Stocks
"While the double-decker insert is in place, elements of the
bridge that need repair, including the decking, would be lifted
away using the temporary bridge as a works platform and
transported by barges to an off-site facility for safe repair
Doesn't say if other river traffic would be allowed to resume at the
same time as cars.
See also: https://www.bbc.co.uk/news/uk-england-london-55086118