Thanks for the comments,
I remember the disaster during it's construction, when an out of control tug-boat hit one of the pylons and caused a span to fall, with workers inside
I was unaware of that accident, as I have been living in Melbourne only 4 years. In any case, from what I read on the internet, the collapse of a section of the bridge during its construction was due to a combination of design & construction issues, unless there was another incident related to a tug-boat, for which I haven't found references.
Regards