Always unnerving to see a building failure like this, it's a chilling reminder of stakes at hand and the kind of responsibility that we all bear in construction industry.
Public will think that the engineer is at fault and engineers will think that the builders/contractors are at fault - it's the way of the land. I am interested to see what the outcome of the inevitable investigation will be. Does anybody know who the engineer is? My rough googling didn't get me anywhere...
CMFEU rep on the news was raging about quality of materials and other popular stuff but given that it's a steel structure my money would be on underdesigned connections or connections that weren't fabricated/built properly.
Well from the video at the top of the linked report, the roof seems to be being held up by five rather weedy looking trusses, two of which have snapped.
Difficult to see past structural failure of the trusses, but that amount of glass must weigh tonnes
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
Glazed roofs are spooky and I always find myself triple-checking thickness of glazing panes, it's exactly the kind of thing that can get bumped up in thickness by a couple of millimetres (for thermal efficiency or something) and end up having an enormous effect on the structure.
Looks like a site weld telescopic spigot for a truss chord? I’m guessing designed as fpbw but probably welded like a seal weld because it wasn’t properly detailed with a bevel and 1:1 weld detail etc etc
Wild speculation ofcourse but would explain a sudden failure
Is the truss framing of steel or aluminum? If of aluminum, unless I am mistaken, field welding would have substantially lowered the strength of the material at the weld and would have needed to be accounted for in the design.
A news article quotes a construction worker quoting 80mm of sag in the truss. News Article As the span in the architectural drawings is approx. 24m, that is a span/L ratio of approx 300. The Australian steel code AS4100 appendix b is span/250. Without knowing what was the pre-camber, or at which stage of construction this deflection was measured, its hard to suggest this as a cause for concern.
You can make an argument based on tables like that one that 80mm L/300 is acceptable deflection, but realistically it’s no way acceptable under dead load alone. You’ll likely hear complaints if a 24m beam is sagging that much.
Whether it has anything to do with the collapse is another question altogether.
I've done a lot of glazing design & engineering. Sometimes, I will try to reach out to the project structural engineer to coordinate. I can count on one hand the structural engineers over the years who have returned my call and take things seriously without me having to absolutely hound them.
Structural engineers, please return the phone calls from the secondary structural designers.
