Tysons Corner Center, trying to freshen up its 20-year-old look, yesterday unveiled a $100 million plan for a face-lift that calls for two new major stores and at least 60 new specialty shops.

To accommodate the expected increase in traffic in an area that is already recognized as having some of the most severe congestion problems in Northern Virginia, Tysons said it will build four multi-tiered parking lots, complete a road that now circles part of the center and pay for half of the cost of a bridge over Rte. 123 to link traffic to the West Park Office complex and the Tysons II shopping center now under construction.

Adding details to plans that have leaked out during the past month, Tysons officials said they planned to spend about twice as much as they had earlier disclosed for the road and mall improvements. The remodeling plans include adding a lower level to the mall (replacing the current truck and storage tunnel), cutting through the existing mall floor to create a two-story atrium and installing a raised, sky-lit roof to bring more light into the center.

The expansion -- which center officials hope will double the number of shoppers at Tysons -- may begin as early as this week with excavation for the first parking lot. When completed in the fall of 1988, the remodeling is expected to increase the sales space from 1.3 million square feet to about 1.8 million square feet. On-site parking places would climb from 5,300 to 9,000 -- about 2,000 more places than the center said it planned to build in its earlier announcements.

"Our first priority is to address the traffic circulation and parking problems," said Geoffrey M. Donoghue, vice president of development for the center.

Within hours of Tysons' announcement, however, Fairfax County's top transportation official expressed deep concern about the additional traffic that would be generated by the mall's expansion. "The last thing we need out there is more stores and more traffic," said Shiva K. Pant.

However, Pant noted that because of prior zoning decisions, the county has few options in limiting development at the Tysons Corner Center. But he said that county officials will invoke what powers they do have in the way of building-permit applications to ensure that needed road improvements are done. "We don't have much control over it. All we can do is make the best of a bad situation."

Tysons officials said they hoped the renovation would attract more fashion-oriented retailers.

Donoghue said the center has had discussions with the leather-goods chain Gucci, the Italian designer Pucci, English boutique Laura Ashley, Alcott & Andrews women's retailer and Carson Pirie Scott, a Chicago retailer that is interested in opening a just-developed specialty store for male and female corporate executives. Discussions have also been held with the home-furnishings store Crate & Barrel.

These would be in addition to the two new department stores, one of which would be the first East Coast store for the successful West Coast retailer, Nordstrom's. Garfinckel's, which currently has a small 23,000-square-foot unit in Tysons, is weighing expanding its unit there by being the second new anchor, with an 80,000-square-foot store.

If Garfinckel's decides against the move, Donoghue said a Neiman-Marcus store was a possibility three to five years from now.

Meanwhile, the existing stores will undergo massive renovation programs, with The Hecht Co. expanding its 234,000-square-foot store by 15,000 square feet.

Adding the individual store costs to the renovation, the face-lift will cost about $175 million, Donoghue said.

The face-lift comes at a time when Tysons II has just begun construction, with plans for at least two major department stores: Bamberger's and Saks Fifth Avenue. But Donoghue said that Tysons Center would have renovated even without Tysons II.

"The center was bought recently with the idea of redevelopment" by Lehndorff Tysons Joint Venture, which primarily represents pension funds in the United States. Tysons ". . . needs updating and a fresh new approach," Donoghue said. "It's been around for 20 years."

Tysons' expansion should add about $80 million in tax revenues and about 2,500 new jobs.