Looks like this may have been a hinged structure (in the center), possibly on rollers at the ends. Just guessing.
May not have had enough torsional strength in the tube frame assembly to keep the rollers on track in case one got hung up. Just a guess here though. Time will tell.
The structure must certainly have been overloaded. If the structural roof members like trusses are in alluminium, then overloading of the roof must have given cause to brittle failure(which is the normal strength characteristics of non ferric members) a colapse which always happens without the strucure going through the elastic/plastic phase of failure( which is usually the warning phase).
Teddy
Acqua Ingegneria-Pisa
A skylight is not weightless(even air is not weightless) as such a structure that is not well supported must fail, be it for reasion of material, craftmanship or design mistake all but point to the same thing-overloading of the supporting structure.
Teddy
Selfweight is a easily calculated quantity and can not be categorized as overload. Wind can produce uplift but the interior air pressure due to wind can be either a positive or negative component, again calculated by standard methods. Overloads connotes loads not envisioned in the original design. That is why I would say the failure is either material defect, workmanship error or design mistake.
Well it depends on you definition of overloading. But as much as I know, your definition does not go the way long. Overloading could be as result of anything, including the loading from wind etc. The much that we can do is to make informed estimates of loads that are imposed on structures. we can never get the exact thing right, but we always try to err on the right side, for if not, why do we after getting the right!!!? weight, still apply the safety factors?
Teddy
