The Alexandria City Council will soon consider zoning changes that for the first time would allow high-rise apartment buildings in Cameron Valley and could doom the controversial Fairchild commerical complex near National Airport.

Next month, the council is expected to receive the first proposed industrial zoning changes in 29 years, which would bring city ordinances into keeping with the mixture of residential and commerical uses now favored in most parts of the city.

One result of the changes would be that buildings as tall as 15 stories could be built along the Beltway in Cameron Valley, according to city officials.

"The zoning laws as they now stand are geared for a heavy industrial city," said planning director Engin Artemel. "Alexandria never developed that way. Most of our areas have some commerical sections and residential sections.

With industrial use, a landowner can build a factory or commerical office. With the more limited commerical use, landowners can build offices or hotels, but cannon build factories for heavy industry. Zoning regulations generally dictate the type of development permitted in an area.

The land that would be affected by the proposed changes rims the eastern and southern edges of the city and is surrounded by increasingly valuable residential property.

Under the proposed changes, 15-story apartment buildings would be permitted along the Beltway, near the future Eisenhower Avenue Metro station. Currently, residential structures are not permitted there. City officials hope the change would help increase the number of rental units in the city, which officials say are now in short supply.

At the northern end of the city, the proposed changes would permit only heavy industrial buildings near the Potomac railroad yards east of Rte. 1. This would block plans by developer Charles Fairchild to build his often delayed office complex, Potomac Center, near the railroad tracks, since the proposed change would not allow offices there.

City officials have opposed the Fairchild development in the past, claiming it is too massive. Fairchild has said it would be an economic boon to the area.

City officials deny the zoning changes were consciously designed to prevent construction of the Fairchild complex, although they acknowledge it would have that effect. Fairchild's project has been delayed for years, partly because of a conflict with the National Park Service over whether the complex would have direct access to George Washington Memorial Parkway, owned by the Park Service.

Planners say the proposed zoning changes would encourage development and increase population density in comparatively unused areas, taking some of the pressure off established areas such as Old Town.