Henry Hart Rice, a real-estate broker who was instrumental in many major developments and won awards for his innovative deals, died in March 1992 at his Manhattan home. He was 80 years old. Mr. Rice, whose primary residence was in Katonah, N.Y., was chairman of James Felt Realty Services in Manhattan, where he worked for 39 years. Among his best-known transactions were helping to devise the complex real-estate finances that saved Carnegie Hall from demolition and assembling the land for the planned community of Reston, Va. Mr. Rice was born in Manhattan. He did not attend college and started work at the age of 15 in the clipping library of The New York Times. Eventually he entered the real-estate business as leasing broker and manager at Hanford & Henderson in 1932, then became a vice president of Butler & Baldwin in 1936. After the WWII he became a broker at Van Dam Mordecai, then at J. Clarence Davis Realty. His first wife, the former Grace Hecker Rice, died in 1974. He is survived by his second wife, the former Margaret (Peggy) Schwarz; a daughter, Dr. Eve Rice of Bedford, N.Y.; a son, Edward, of Reston, Va.; a stepson, Edwin Stern of Manhattan; three stepdaughters, Maggie Terris of Watertown, Mass., Mary Grossman of Manhattan and Suzy Kunhardt of Chappaqua, N.Y.; four grandchildren and 13 stepgrandchildren.