Having worked in Montreal several years ago, specializing in the rehabilitation of reinforced concrete structures, including parking garages, it is quite possible that chloride penetration, corrosion of the rebar and resulting delamination of the concrete may have contributed to the collapse. Might not be the only contributing factor, won't know until investigation is complete. It is a tough environment with the amount of salt used on the roads in winter.
I have seen several parking garages in various cities across the country where extensive 'potholes' in the concrete (delaminations) had been covered over by the maintenance crews with an asphalt topping to provide a smooth driving surface .... without repairing the concrete!!
The 10km on the columns would refer to the speed limit in the garage ... 10 kilometers/hour.