The D.C. Zoning commission has given final approval to the creation of a new zone intended to encourage the construction of hotels and apartment buildings along a stretch of Massachusetts Avenue NW bordering downtown Washington.

The commission voted unanimously Thursday to create the zone along both sides of the thoroughfare from Union Station Plaza almost to 14th Street NW, including an area adjoining the new $100-million convention center being built south of New York Avenue and west of Ninth Street NW.

Within the area, construction of buildings contaning specified amounts of hotels and residential space will be permitted up to a 130-foot height instead of the current 90-foot limit. Most of the specific area currently is designated for apartments and office buildings.

Without the new zone, city planning officials said economic trends would dictate that the area be developed chiefly for office buildings. Many residents protested, saying the area should be rezoned strictly for residences. r

Responding in part of official comments from the National Capital Planning Commission, the zoning body voted to limit to 90 feet high the front portions of buildings facing Mount Vernon Square, the site of the old D.C. Public Library at Seventh Street and Massachusetts Avenue NW. Rear portions of the buildings, more than 30 feet from the front wall, may rise to whatever height the law otherwise allows -- a maximum of 130 feet.

The new zoning category will take effect when the commission's official order is published in the D.C. Register, probably in several weeks.