Stanford Shopping Center will enjoy a shopping spree of its own over the next two years, spending millions of dollars to bring 20 to 30 small shops, a handful of restaurants and new outdoor gathering spaces, officials said Thursday at an architectural unveiling ceremony.

Almost 60 years old, the upscale center will undergo two distinct but complementary projects designed by San Francisco firm BAR Architects. The first project involves a renovation of the shopping center's common areas, with a focus on expanding walkways and gathering places. The second involves the addition of the shops and restaurants, which will sit in the footprint of the existing Bloomingdale's building.

"This center is a hub in this community, and as such we place significant focus on providing an incredible experience for each person that visits," said Josh Kalkhorst, the center's property manager. "To that end, we are further committing to the community of Palo Alto, our shoppers and our retailers."

A new open plaza at the west end of the center will represent the most drastic renovation of the common areas. The plaza, which will feature gardens and a stretch of lawn where people can sit, could serve as a venue for special events. Plans also include the addition of an open-air fireplace with surrounding seating to the pavilion near Louis Vuitton. Center representatives said art from local artists will be on display in three designated outdoor locations. "Outdoor living rooms," or outdoor seating areas similar to the one near Louis Vuitton and Macy's, will be built throughout the center.

Renovation of the common areas should begin by the end of this summer and be completed by the holiday season of 2015, according to Kathy Shields, senior vice president of development at Simon Property Group, which owns the center. Hours of operation will remain the same during construction.

"Let me assure you," Shields said Thursday, "that the qualities that already make the center very special – the arboretum feel of the center, the floral arrangements, the seasonal color – all of those qualities will be celebrated and enhanced."

Once Bloomingdale's opens its new building later this year, the center will demolish the old store behind it and begin construction on 100,000 square feet of new stores and restaurants. The group of retailers will be organized into four multi-tenant buildings, center representatives said Thursday. The new stores will be of the ilk of the current variety, with many geared toward high-end fashion, Shields said. The project should be completed by the spring of 2016, just in time for the center's 60th anniversary.

Among those who attended Thursday's ceremony were the owners of Edwards – Everything Travel, formerly Edwards Luggage, who have been tenants for most of the center's history.

"As a local Palo Alto family and one of the original tenants ... we are looking forward to this major improvement," said co-owner Marty Reininger.

John Lee, lead architect from BAR Architects, said the new buildings will reinforce the shopping center's established aesthetic, which draws heavily from outdoor landscaping.

"Its distinctive character is defined more by the wonderful landscape spaces between the buildings than by the architecture itself," Lee said. "Our goal … is to enhance and improve on the special features already existing but also to add new features, an aesthetic that looks toward the future."

Design and construction plans for the new buildings also call for energy-conserving technologies and building materials. Other updates include installing drought-resistant plants and a sustainable irrigation system, which will operate in concert with existing healthy trees and seasonal flora displays.

Representatives described the renovations Thursday as a "multi-million dollar investment," but did not specify the actual cost.

Stanford Shopping Center's transformation began in 2012, with a proposal calling for the demolition of the original Bloomingdale's and the addition of five buildings, including the current stand-alone site of Fleming's Steakhouse.