Dome

Detail, triangular (or diagrid) framing pattern of structural steel; The six-story base of the headquarters building was commissioned by the founder, William Randolph Hearst, and awarded to the architect Joseph Urban. The building was completed in 1928 at a cost of $2 million and contained 40,000 square feet (3,700 m2). The original cast stone facade has been preserved in the new design as a designated Landmark site. The base was intended for a skyscraper, never built because of the Great Depression. The new tower addition was completed nearly eighty years later, and 2,000 Hearst employees moved in on June 26, 2006. The uncommon triangular framing pattern (also known as a diagrid) required 9,500 metric tons (10,480 tons) of structural steel, reportedly about 20% less than a conventional steel frame. Source: Wikipedia; http://en.wikipedia.org/wiki/Main_Page (accessed 9/6/2015)