Can choose submajors such as structures (large things like the harbour bridge), Enviromental (with more focus on the effects that the structure will have on the enviroment), Water (which is obviously about water), and Construction (also obvious). At least at UTS these are the major ones.
Will most likely work in areas with construction of buildings.
Mechanical Engineers:
Deal with dynamic objects. (Moving).
Will need some electronics work as most systems are controlled by electronics now.
Will need a greater level of dedication to maths. (Not saying it is overly hard, that you need to be able to put in the effort to understand it.)
Can move on into areas such as transport, and biomedical (as those things require precision movement).