Wood shafts are pretty common in this type of construction. Owner's think they are saving money by selecting wood instead of concrete block or steel reinforced concrete but in the end they are way more of a pain in the ass to put together.
They likely have the ramp down into the parkade at that location where the crane is off the back lane. For this one, 1 level of parkade will provide the minimum number of spots required.
Best guess they are stacking trailers there on top of that steel frame, since there is no way they would be able to put trailers on 17th or 5th or the the lane. For sure they would have a parkade under this building.