This is definitely formwork and not scaffold, but close enough for the headline I suppose. Very tragic indeed. Its hard to tell how this is setup in the link originally posted, the picture below is a bit clearer. Looks like beams running beside the columns and shearwall, which cantilever out past the slab edge and support the aluminum trusses spanning parallel with the slab edge. It appears the beam along side the shear wall failed - either the beam itself or its supports.
