Thanks for your reply Lasse.
See images of radial cables in the skp model below.


The design you linked to shows the cables attached not to the columns, but to bowed vertical beams which are attached to the columns. Following your engineers' logic that cables are an inherently efficient means of bracing a structure (although I'm not aware of any suspended structure on this scale which is suited to a moving foundation, i.e. ship or oil platform), it would seem that the material savings allowed by the use of cables are then spent on the extra bowed vertical beams. If I had the choice I would take the material costs from the extra vertical beams and the cables and spend it on rigid connections between the trusses and columns, thereby freeing up almost all the space above the trusses for development.
Unfortunately it's extremely difficult to even begin designing (even a sketch design) when the underlying structure is according to your engineers both a) very well thought through and therefore a coherent structure in which every element is dependant on another, but also b) large elements of the structure can apparently be moved around to suit planning. I understand (in spite of the comprehensive engineer's report) that the whole idea is fairly conceptual, but a moving target is very hard to hit.
@unknownuser said:
"Putting the legs at the corners results in a larger span, that is, more cantilevering, and thus requires a bigger truss which wastes materials. Right now, the largest span is 200', which means the furthest cantilevering is 100'. If spars were at the corners there would be a 400' span and thus 200' cantilevering.
I follow the logic of reducing the span of the trusses, but surely this is at the expense of stability? As I said, I'm no marine engineer, but the same principle applies at sea as on land: the farther apart the legs/supports are the lower the centre of gravity and the more stable the structure. Besides, in the current structure the trusses aren't cantilevered- they're suspended from the columns via the cables. In section the platform is effectively a suspension bridge, but AFAIK suspended structures rely on an extremely stable foundation whereas cantilevered structures are better suited to less stable conditions.
Sorry for banging on about this, I'm just intrigued about the many ways in which this structure strays from standard engineering practice.
We proposed an art gallery, communal studios, performance spaces which would be built 4 storeys up, spanning between several buildings effectively roofing a large loading bay, but which could only be accessed via multiple private apartments on the 4th floor to which it was connected. High Bullsh*t, and purely theoretical I know, but the idea was to blur private space, public space and communal space and also to explore the legal boundaries of the relative liberty we are afforded in our own homes (smoking, nudity, building regulations, etc) compared to that allowed in public spaces and buildings.... and no, we did not get naked for the presentation.



