LOS ANGELES — Kilroy Realty Corporation (KRC)has purchased Columbia Square, a historic Hollywood media campus, and Tribeca West, a West Los Angeles entertainment-oriented office property, for a total of $138 million. Columbia Square sold for $65 million, while the acquisition of Tribeca West is expected to close early in the fourth quarter for $73 million. Tribeca West is a 151,000-square-foot, three-story office campus that is currently 96 percent leased.The Columbia Square acquisition included a 96,000-square-foot campus that contained three historic office buildings. It was the former home of the CBS network’s Los Angeles radio and television operations. The 4.7-acre site is fully entitled for an office, retail and multifamily mixed-use project under a 15-year development agreement. KRC is planning a multi-phase redevelopment and development that would upgrade its existing office buildings and add 550,000 square feet of office, retail and residential space to the campus. The $300-million project is scheduled to begin in mid-2013. Phase I is expected to be complete in 2015.