I'm with jayrod, double tees typically have very short bearing lengths; I would not be surprised if the spandrel beam was pushed outward and the remaining bearing length was insufficient.
Ian Riley, PE, SE
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
We have a report of a similar failure in a precast parking garage in the US frequently. Why don't the precasters insist on tying these things together?
hokie66, because it's a race to the bottom (cost) for these garages and too many other structures. If they tie them together, it might cost .0001% more.
Do they know that the first spandrel moving outward was the initial failure mechanism? Could a double-T stem failure impacting the spandrel beam caused additional secondary failures. Including the next bay over?
I agree with Jed on pre-cast parking garages. To me, most of them are glorified lincoln logs stacked into their final configuration.
Coincidentally, my company was contacted the same day this happened to help design some emergency shoring for a precast parking garage in the Southeast US. Apparently the double tee stems had walked off the bearing pads and cracks had initiated at the re-entrant corner of the dapped end. They are also discussing launching and investigation of 40+ more similar structures to evaluate how widespread this problem is.
30 years later a Google search on
"Cave on Foods" brings up this Wiki article;
Wiki said:
Station Square collapse
From Wikipedia, the free encyclopedia
The Station Square collapse, also known as the Save-On-Foods collapse, was a major structural failure of a new supermarket and parking facility in Burnaby, British Columbia, Canada. On April 23, 1988, within minutes of the grand opening of a new Save-On-Foods store, a 6,400 square foot portion of the roof collapsed sending the rooftop parking deck and 20 automobiles crashing into the produce section below. There were no fatalities and 21 people were treated in hospital.[1] In the years following the collapse, recommendations from a commission of inquiry resulted in significant changes to the practice of architecture and engineering throughout British Columbia.
