An adjustable platform assembly for supporting workers and supplies about an elevated work site, the platform assembly being movably supported on an articulable support, the platform comprising a stationary rear bridging panel arrangement having an elongated side platform member comprising a floor and railing assembly at each end thereof, wherein each elongated side platform member floor and railing assembly is independently movable on support members forwardly, rearwardly, transversely and angularly with respect to the bridging panel arrangement, to change the platform assembly back and forth between a generally “H” shape to a generally “U” shape, or any skewed combination thereof, as required.