Several members of the D.C. City Council expressed alarm yesterday at an engineering report finding that beams supporting walkways in the District's new Municipal Center could collapse without warning, while city workers in the building appeared to be going about business as usual.

"I have walked across that structure in question, and I am distressed to find out it is not structurally sound," said council member Frank Smith (D-Ward 1), who represents the area around the Municipal Center at 14th and U streets NW.

Council member Nadine P. Winter (D-Ward 6), who heads the council's Committee on Public Works, voiced "deep concern" about the building's flaws.

Winter "is alarmed about the safety and well-being of government employes and the public that go in and out of the building," said David Watson, Winter's legislative assistant.

Winter has scheduled a meeting tomorrow with Public Works Director John E. Touchstone to discuss the problems, Watson said.

Council member Carol Schwartz (R-At Large) urged Mayor Marion Barry to remove workers from any unsafe areas.

"I would hope the mayor would get public employes out of a building if there is any hint of danger," Schwartz said.

The April 18 engineering report, commissioned by the D.C. Department of Public Works, concluded that repairs made to the beams in 1984 are inadequate and that new, permanent supports must be designed to make the walkways safe.

At the engineering report's recommendation, the District has erected temporary supports to brace the beams for the building's four walkways, on the third through sixth floors.

Disclosure of the findings yesterday left some employes at the building unconcerned, however.

"All my people are here today," said Keith Vance, director of the D.C. Office of Campaign Finance, housed in the Municipal Center.

"The walkways are on the other side" of the building, he added, so if they collapsed it would not affect the campaign finance office portion.

"I figure if it goes, there would be some warning," said a police officer stationed on the first floor of the center.

"No one seems alarmed about it," said Diane Waiters, an employe of the D.C. Office of Personnel, which moved to the building two weeks ago.

Project officials said previously that the Municipal Center's walkways are safe and that, with the temporary braces, the structure has three or four times the support it needs.

The $41.7 million project is already more than a year behind schedule.

Cyril Crandon, acting administrator of design, engineering and construction at the Public Works Department, said yesterday that the structural engineering firm that designed the building, VVKR Inc., should get back to the city in about a week with a design and cost estimates for permanent reinforcements.

Council member Smith said he was sure the problems could be fixed but blamed city officials for "dragging on and on" with repair work that he said should have been done by now.

"I think the government is in for some criticism," Smith said, adding that the project "has not been watched closely enough."