I used to live nearby and bicycled across this bridge for more than 20 years.
The bridge was extensively rebuilt in 1986 or 1987, closed to traffic from early spring till about September.
The arched approaches were torn down to the arches themselves and new material used to restore the roadway, and the bascule mechanism refitted with a new motor.
After the rebuilding, at first it would take about 30 minutes for the bridge to open and close, it was explained that a temporary low power motor was being used.
Then a few weeks later it was again able to open and close in about 1 minute.
Considering how much effort was spent, I find it hard to believe it is now considered structurally deficient, unless it refers to the central bascule span which didn't seem to have any significant work done on it at the time (except for replacement of the motor)