Going head-to-head over ramps

Internationally known architects involved with two competing projects on the Rose Kennedy Greenway yesterday went toe-to-toe over whether tunnel access ramps should -- or could -- be covered.

In a spirited exchange at a meeting of the Mayor's Central Artery Completion Task Force, Daniel Libeskind, who created the master plan for the rebuilding of New York's new World Trade Center complex, and Moshe Safdie, who has designed projects worldwide, from the Peabody Essex Museum in Salem to the soon to open Yad Vashem Holocaust Museum in Jerusalem, sparred and briefly interrupted each other while defending their concepts.

Both dressed in black suits and collarless shirts -- Libeskind's black, Safdie's white -- the two renowned and impassioned architects became animated over a central feature of their proposals for the Surface Artery block between High Street and the Evelyn Moakley Bridge.

Firing the first salvo of the "ramp wars," Libeskind, who has proposed an irregularly shaped, modernistic box structure to house a New Center for Arts and Culture, vigorously defended leaving an onramp and an offramp for the Central Artery tunnel uncovered.

"There is something memorable about the two ramps," Libeskind said, taking a bold position at odds with the assumptions of most observers of park design, who have assumed making them disappear was a major objective of placing a building rather than a park on the block.

"They are part of the archaeology of the site," Libeskind said. "It is important not to impact an underground system so sophisticated, so delicate, that any impact would have a ripple effect on the whole system."

The block up for grabs, known as Parcel 18, lies between the extensive future Wharf District parks and the three blocks near South Station that were assigned years ago to the Massachusetts Horticultural Society.

The project manager for the Libeskind project, proposed by Combined Jewish Philanthropies of Greater Boston and the Jewish Community Centers of Greater Boston, elaborated, saying the complex ventilation system for the Big Dig tunnels is fragile and at its limit in that location. "We think it unwise to hinge a proposal on something that may be feasible but if it is would be extremely expensive and difficult to permit," said Carol Gladstone.

Safdie, who has proposed a radical boat-like structure over a rising strip of parkland for the Boston Museum Project, fairly jumped out of his seat to defend his design. He insisted covering the highway ramps is quite possible.

"We've done the homework. There's extraordinary benefits to covering the ramps," Safdie said. "Any suggestion that leaving them open is more 'sustainable' is nonsense."

"We are not building fantasies," retorted Libeskind, arguing that it would be difficult to design a structure large enough to cover the ramps that would not cast shadows.

"We did," shot back Safdie.

The two personalities brought an unusual emotional level to the bimonthly meetings, which are usually subdued discussions about grassy vs. paved surfaces, trees and shrubs, and the slow progress of Greenway park designs.

The arts and culture proposal and the history museum plan are two of four ideas submitted recently to fill the large block of space between International Place and Rowes Wharf.

The two other proposals, presented to the task force yesterday, are for a Greenway Arts Pavilion that would double as a refuge and drop-off for tour buses, and for a permanent, year-round farmers' market to be known as Boston Public Market.

But the New Center for Arts and Culture, at 63,000 square feet placed between the gaping highway ramps, and the Boston Museum Project, at 163,000 square feet and sprawling over them, are considered the front-runners.

Although the request for proposals issued by the Massachusetts Turnpike Authority and guidelines from the City of Boston do not require that the ramps be covered, a turnpike official said last week that it was desirable.

And yesterday, Fred Yalouris, director of architecture for the Turnpike Authority and the Big Dig, said, "We expect some of the ramps where technically feasible should be covered, and will consider that in evaluating the proposals."

Libeskind, wearing his trademark black Montana cowboy boots and square glasses, said, "Smaller is better" and argued the arts and culture center would be "not an obstacle, not a massive monument" on the Greenway.

Libeskind said he respects Safdie's work. Safdie would not say what he thought of Libeskind's creations, but, speaking of the current project for Boston, he said: "I think it's got serious problems. You can't do this site on the cheap. The ramps have to be dealt with -- otherwise they become barriers."

Turnpike officials said they hope to designate one of the proposals for the site in about six weeks. The arts and culture center could be completed by 2009, the museum by 2011, officials for each project said.

Thomas C. Palmer Jr. can be reached at tpalmer@globe.com.