By rezoning a tiny parcel of land, the Fairfax County Board of Supervisors this week cleared the way for construction of a $75 million office park facing the Dulles Toll Road near near Tysons Corner.

After more than 18 months of negotiations involving developers, residents and county officials, construction will begin within 30 days on Tysons-Dulles office park, according to Alan I. Kay, one of the three developers now involved in the project.

When first proposed, plans called for construction of three 12-story buildings on 15 acres at the intersection of the Dulles Toll Road and Springhill Road.

Developers cut the plan in half and now will build three six-story buildings totaling almost 500,000 square feet. The complex will be built around a central plaza and will front on the Dulles Toll Road.

Kay, the John G. Georgelas & Sons development company and the Milton Co. will develop the project.

The current plan calls for construction under the existing industrial zoning classification, which covered all but a quarter-acre of the 15-acre site. This week the Board of Supervisors voted to rezone that quarter-acre from residential to industrial uses.

"We are going to build what we can by right in the industrial status," said Tom Georgelas, a spokesman for the John Georgelas firm.

The development partners have changed during the long wait to get the project approved. Robert Bass, one of the Fort Worth-based Bass brothers, once was involved in the project but sold his interest to Rozansky & Kay Construction several months ago. Last week Rozansky & Kay announced its dissolution at the end of this year after 26 years in the development and construction business.

Kay said this week he would be developing the Tysons-Dulles project as Alan I. Kay rather than as Rozansky & Kay. Also involved in the development with Georgelas and Kay is Milton Schneiderman, head of the Milton Co.

Developers backed away from their original plans for three 12-story towers after residents of nearby subdivisions objected to the height and density of that proposal. Odrick's Corner, one of Fairax County's oldest black neighborhoods, is close by and would be drastically affected by the project, area residents complained.

In addition to the changes in developers and size of the project, the project has changed architects. The final design was done by the Washington-based architectural firm of Weihe, Black, Jeffries, Strassman & Dove.

The three buildings containing approximately 165,000 square feet each will be built "around a central plaza," and "each building will have its own atrium," said architect George Dove.

"The central plaza faces the Dulles Toll Road. Trees surrrounding a nearby Vepco power station will remain and a very expensive landscaping plan" is part of the total package, Dove said.

Milton Co. and John Georgelas Co. are considering moving their headquarters to the project, Tom Georgelas said.

He added that Kay would build two of the three buildings. The third would be developed by Georgelas and the Milton Co. Georgelas said he expects construction to begin simultaneously on two of the three buildings. According to Kay, that will be within 30 days.

The site is considered a prime Tysons Corner location by commercial brokers because of its frontage on the Dulles corridor. If work proceeds as scheduled, it will be the first new commercial office park to open in the Tysons area fronting on the toll road. Adjacent to the site are low-rise warehouse buildings. Southwest of the site along the Dulles Toll Road at the Leesburg Pike exit is the 23-story Sheraton Hotel now under construction.

The rezoning ends months of community concern about the future of the site, but it does not end their concern over transportation problems in the area. The McLean Citizens Association sought to delay county action on the project to get developers to concede to make additional traffic improvements, but their efforts were unsuccessful. Developers have promised to make major improvements to Springhill Road and Tyco Road.

George Lilly, chairman of the County Planning Commission, said he supported the project even though there were "transportation issues which are apparently not going to be resolved in connection with this application, but may have to be dealt with in some fashion later on."

Lilly said during planning commission hearings that the rezoning "is a very small remaining piece that is in effect a consolidation of other properties. This brings the smaller piece in line" with the zoning on adjacent property, he said.

"The property's location makes it a natural gateway to Tysons Corner from the north and from the Dulles Acess road," according to Martin Walsh, project attorney.