A woman whose husband was killed two years ago while working as a carpentry foreman on the new D.C. Municipal Center settled for $550,000 yesterday in a lawsuit against the construction management firm that supervised the building.

Lawrence Acord, 37, of Forestville was killed July 31, 1984, while working on the ground floor of the structure at 14th and U streets NW when he was struck on the head by a cinder block that fell six stories from a crane.

Patrick M. Regan, attorney for Acord's widow Suzanne, said the settlement was reached with the McLaughlin Construction Management Corp., which has the construction management contract for the nearly completed building, and its parent corporation, Mellon-Stuart Co. The city was not a party to the suit.

A portion of the settlement will be used to establish college trust funds for the Acords' 16-year-old son and 12-year-old daughter. "The tragedy, in our opinion, was easily avoidable if the construction manager and the parent corporation had taken reasonable care to inspect and enforce the safety codes," Regan said after the settlement, which came shortly before the suit was to go to trial in U.S. District Court.

He said pretrial disclosures in the case showed that no McLaughlin personnel, only employes of Mellon-Stuart, were at the construction site at the time of the accident. Attorneys for McLaughlin and Mellon-Stuart could not be reached for comment.