Positioning itself as a neighborhood green space and cultural gateway, Walker Art Center will add a new glass-walled entrance pavilion, groves of trees and acres of new grass as part of a $75 million project to be announced Tuesday.

“This plan envelops the whole building in a carpet of green,” said Walker director Olga Viso, who led the six year planning effort.

The Walker’s plans are designed to unify a 19-acre cultural “campus,” including the Minneapolis Sculpture Garden, that stands as an anchor and gateway to the theater and arts district that Minneapolis intends to develop along Hennepin Avenue to the Mississippi River.

The centerpiece is a pavilion on Walker’s north side with an expanded cafe and patios on Vineland Place opposite the sculpture garden.

The grassy hill west of the building will remain an open field suitable for popular events like Rock the Garden and the Internet Cat Video Festival, but it will be recontoured and softened with small clumps of trees. A staircase beside the pavilion will provide access to hillside pathways and to a new seasonal entrance to the Walker’s shop and theater.

On the east side, the concrete and granite plazas along Hennepin will be replaced by grassy berms, flowering trees and sidewalks.

Walker officials already have nearly $60 million in hand, including $10 million in public money.

Minneapolis philanthropists Margaret and Angus Wurtele, a Walker board member for more than 40 years, gave $20 million, the largest gift in the center’s history. Other board members and Walker supporters chipped in an additional $29.8 million.

The public money is dedicated to renovation of the 11-acre Minneapolis Sculpture Garden. The state of Minnesota provided $8.5 million in bonding funds; another $1.5 million came from the Mississippi Watershed Management Organization.

The remaining $15.2 million will be raised from private sources as the project unfolds.

The Minneapolis Park and Recreation Board, which owns the sculpture garden’s land, is overseeing the garden renovation. Minneapolis landscape architect Tom Oslund is doing garden plans that the Park Board is expected to approve April 15.

Construction is scheduled to start in September and be completed by fall 2016. The sculpture garden renovation will begin simultaneously, with an expected finish in spring 2017.

As a result, the Walker is looking for an offsite location for next year’s Rock the Garden event.

Neighborhood anchor, city gateway

The new entrance pavilion is the key, strengthening the Walker’s ties to the landscape, neighborhood and especially the sculpture garden. It also attempts to solve significant circulation and access problems in the existing building which is a mash-up of two towers with ambiguous entrances leading to a maze of confusing stairways and concourses.

“What this does is clarify the entrance by placing it front and center,” said architect Joan Soranno of the Minneapolis firm HGA, who designed the pavilion with colleague John Cook.

Their plan deftly reshapes the building by adding glass walls, removing visibility barriers, and straightening architectural kinks. An essay in modernism, it is designed to solve problems not to express the architects’ egos.

“We very consciously said we didn’t want to add a third charm to the charm bracelet,” Soranno said, alluding to their architectural predecessors.

Pavilion and cafe

The one-story pavilion will nestle into the hillside facing the sculpture garden and have a grass roof that can serve as a viewing platform for garden events. A skylight and glass walls will admit light and garden vistas, while a bronze canopy and signage tie the pavilion to the Walker’s 1971 brick-clad tower designed by Edward Larrabee Barnes. It will house an expanded cafe and an interior “art wall” for which the Walker plans to commission new visuals every year.

Visitors arriving via the Walker’s underground parking ramp, as 70 percent do, will enter the pavilion via a wide concourse with views of the sculpture garden, rather than through the narrow windowless corridor that now links the ramp to the current cinema lobby.

The new concourse is one of the renovation’s most expensive features because building it requires moving air shafts, fans, cooling systems, and other mechanical features, some of which date to the Walker’s original 1927 building.

“To blow that path we had to change a lot of infrastructure,” said Cook. “Every time you make a move there’s a land mine.”

The cinema lobby on the ground floor of the Barnes building also will be revamped. A granite-covered ziggurat of outside steps will be removed and replaced by a glass wall and patio on the north. Inside, a stack of benches will be gutted to open the space, enabling visitors to immediately see the stairways to the Walker’s two wings: the Barnes tower on the north and the 2005 Herzog and de Meuron-designed tower on the south.

Landscaping around the Walker building is by Inside Outside, a hotshot Amsterdam firm headed by Petra Blaisse and Jana Crepon, whose credits range from Munich to Beijing. The groves of maple, pine, birch and other trees that they plan to scatter across the hillside visually echo the fan-like arrangement of galleries, lobbies and theater in Herzog and de Meuron’s tower. By replacing the granite plazas with grass on the east and north sides of the complex, they are restoring something of the natural surroundings that originally framed the Barnes tower in 1971.

“We set out to address circulation issues, improve access from the garage, and develop a more dynamic entrance from the Sculpture Garden,” said Viso. “The result is an unprecedented moment, a generational moment that will complete a gateway to the downtown cultural district.”