The (17 years older: 1964 Vs 1981) Forth Road Bridge had a replacement built (partially to give a capacity boost as well, but cable issues pressed the matter) and then closed for 6 months while they fixed before it reopened for non-motorised traffic / local buses - a much lighter load than before (its monthly traffic used to be it's daily traffic)
The Humber Bridge at least doesn't have the strain of about thrice the traffic it was designed for. It gets about 120,000 a week (the new Forth Bridge gets 2/3rds of that a day)