Demolition is making steady progress at 550 Washington Street in Hudson Square, the site of Google’s newest 1.3-million-square-foot building. Workers continue to dismantle part of the steel superstructure of St. John’s Terminal, which directly overlooks the Hudson River. Designed by COOKFOX Architects and developed by Oxford Properties, the new facility will join two other nearby buildings at 315 Hudson Street and 345 Hudson Street to form a 1.7-million-square-foot “Googleplex.”