Minneapolis architect Ralph Rapson lived to 93, long enough to see his two most acclaimed buildings -- the glass-fronted Guthrie Theater on Vineland Place and the pavilion-like Pillsbury House on Lake Minnetonka -- torn down. He didn't live long enough to see his largest, most idealistic and most controversial project -- Cedar Square West -- renovated back to its 1970s-era design.

That's what's about to happen. The 40-year-old high-rise complex on the University of Minnesota's West Bank -- now named Riverside Plaza -- is poised for a $55 million upgrade.

Last month both the Minneapolis Heritage Preservation Commission and the Minnesota State Review Board recommended that the complex be listed on the National Register of Historic Places, though it is not yet 50 years old, the usual cutoff.

The historic designation enables Riverside Plaza's owner, Sherman Associates, to receive sizable state and federal historic tax credits to assist with the project's financing -- and assures that the renovation will receive the scrutiny that a historic property deserves.

Preservationists -- currently attuned to saving buildings of the recent past -- have enthusiastically supported the designation. Others find it shocking. Why would you want to preserve a pile of concrete high-rises that many consider ugly? How could something built in our lifetime be historic?

Let me count the ways.

Visible from the freeways that ring it, what is commonly called Cedar-Riverside is a physical landmark -- a signature on the city skyline. (It's also a nationally known pop culture icon as home to Mary Richards for part of "The Mary Tyler Moore Show.") More important, it is a social and architectural landmark -- a significant and surprisingly intact example of Rapson's Modernist legacy and a monument to an idealistic era when architects, planners and developers thought they could change human behavior.

A Utopian idea

The idea behind Cedar-Riverside was simple, compelling -- and wrong: People of all backgrounds and income would want to live together in a well designed high-density community in the core city. Students and seniors, blacks and whites, suburbanites and urbanites would relish rubbing shoulders in a living place close to the university, downtown, theaters and art centers.

Rapson deeply believed in this vision, and he tutored his clients, developers Keith Heller and Gloria Segal, as he took them to visit new towns nationwide and in Europe.

By 1970, they had assembled an unwieldy team that included environmental planners Lawrence Halprin, who had designed Nicollet Mall, transportation planning firm Barton-Aschman and Heiki von Hertzen, the force behind Finnish new town Tapiola. The plan envisioned 100 acres of modern towers housing 30,000 people, a commercial center and an elevated trolley.

In 1971, the plan gained national credibility and funding when the federal Department of Housing and Urban Development (HUD) designated it its first "New-Town-in-Town," a high-minded program to fund mixed-income redevelopment in cities. (Only one other of the seven New Towns planned -- on Roosevelt Island in New York City -- was built.)

A crack in the vision

Cedar Square West -- Stage One of this plan -- included 15 low- and high-rise buildings with commercial space, parking beneath and 1,300 housing units ranging from subsidized to luxury. Completed in 1973, it was the only stage built.

Soon after the eight-acre complex was completed, the vision began to crack. It was easier to attract residents to the subsidized units than to the luxury units. Blacks tended to rent in Building F. Although subsidized housing could be dispersed among the buildings, to get a mortgage the luxury units had to be grouped in one building, Chase. Other residents resented the sauna and exercise room reserved for the "luxury" tenants.

Cost-cutting meant that three instead of six elevators were installed for the 39-story Mc-Knight Building, the tallest tower, consigning residents to long waits. Water pipes weren't insulated, causing pipes to burst.

Other parts of Rapson's design weren't implemented. To express the mix of people living there, he wanted individual tenants to choose the colors for the concrete panels. Fearful they would be filled with graffiti, the developers nixed that idea. Instead, the design mixed primary-colored highlights of blue, red and white with mostly charcoal-colored panels. Later, to cover up water damage, the panels were painted peach and brown, which gives them a sorry look.

In 1973, neighborhood activists sued HUD for conducting an inadequate environmental assessment report. Plans for any further development were eventually ditched, and in 1985 the project was foreclosed.

By 1988, when Sherman Associates bought the property, the complex was 50 percent occupied and HUD hadn't done maintenance in years, president George Sherman said. At that time, Sherman Associates did $8 million of basic upgrades and added an elevator. Now, 22 years later, major systems -- heating, plumbing, electricity -- desperately need overhauls.

Most of the rehab will be inside the walls -- plumbing, electrical and air-handling systems will be redone. Windows in apartments will be rehabbed and patio doors replaced. Public areas will be refinished and the exterior concrete and stucco repaired. The most visible changes will be softer landscaping -- and the return of the original bright-colored panels.

Riverside Plaza has been controversial, from its origins in the social idealism of the 1960s, through opposition from neighborhood residents seasoned by anti-Vietnam War protests, to today, when some argue the whole place should be torn down.

The project's heady goal of a high-density, mixed-income urban community didn't pan out. The boxy Modernism of the 1970s is largely reviled. But for 40 years the complex has provided affordable housing for thousands of people in a near-downtown location. Largely, those have been immigrants -- first waves of Vietnamese and Hmong, now Somalis and East Africans.

The renovation will improve the living conditions of Riverside Plaza's 4,000 residents. It will also brighten the complex's skyline presence. Ralph Rapson, an idealist and Modernist to the end, would roundly applaud both outcomes.

Linda Mack writes regularly about architecture.