This is the so called "swinging bridge" or "pontoon bridge" which only opens when seagoing vessels pass through.
It used to take car traffic however since early 70's it is only for pedestrians.
Only one exception in February, the day the carnival parade has to get through.
The moment the bridge opens then some ferries come into action.
This "pontoon bridge" is well maintained as it is taken out of commission every 10 years for a full blast and repaint at the dockyard.
The new Anna bridge has been put into place whcich shortens the connection between Punda and Otrabanda, but you can still drive around the bay.
p.s. various other threads mention Curacao.