The University of the District of Columbia's vice president for administrative affairs took over yesterday as interim president of the school, replacing Benjamin H. Alexander who submitted his resignation after a stormy term of less than a year.

In a brief statement, Ronald H. Brown, chairman of the UDC trustees, said Claude A. Ford, a 55-year-old architect, would serve in the university's top spot throughout the summer. But Brown said a new "long-term" president is expected to take office before the start of the fall term.

After several weeks of reports that a majority of the UDC board was pressing him to quit, Alexander, 61, announced on Saturday that he planned to resign. He issued a statement yesterday morning that he had reached an agreement with the board to resign "on or before July 31."

However, Brown told a reporter that he and the president had decided that Alexander would leave his office "as fast as possible," and he said that Ford became the interim president yesterday afternoon. Brown said Alexander will be allowed to remain in the UDC president's house until the end of July.

Last night Alexander said he agreed to leave quickly so "the issue would not be kept alive and hurt the university," but he declined further comment. On Saturday, he said he was resigning because he couldn't accomplish his goals of upgrading the university because of "restrictions" imposed by the board and continuing opposition from faculty.

In his statement yesterday, Alexander noted that Mayor Marion Barry recently had announced six new appointments to UDC's 15-member board of trustees, and said, "This would seem to provide an ideal opportunity for me to pursue new career objectives."

Brown would not disclose the terms of the signed agreement between Alexander and the board and declined to say whether Alexander would be paid for the balance of his three-year contract. His salary as president has been $59,500 a year.

Robert L. Green, a dean at Michigan State University and prominent civil rights activist, reportedly was contacted about the job by UDC trustees late last week. Yesterday Green told the Lansing (Mich.) State Journal that officials of "several universities," including UDC, had spoken to him about becoming president. Green said he was "looking closely" at the offers, the newspaper reported.

Several board members said privately that they were upset Alexander had announced his resignation and criticized the board, instead of making a joint statement with Brown about his departure. But none of them would respond publicly to Alexander's criticism.

"I wish him well," Brown remarked. "We're looking to the future. We think it serves no purpose to dwell on the past."

Several board members also said privately that a majority of the trustees reached a "concensus" last month that Alexander should resign or be fired.

Late yesterday, Frank P. Bolden, president of the D.C. Federation of Civic Associations, called on the D.C. City Council to investigate Alexander's departure and the opposition he encountered from the trustees and the Faculty Senate.

"There was not a whole lot going on in the way of education before Alexander came," said Bolden, whose group honored the outgoing president on Saturday as its Father of the Year. "He was trying to change this and apparently the board doesn't want to."

Bolden said the trustees should delay appointing a new permanent president, but Brown said the board intends to move quickly, though no announcement is planned at the group's regular meeting tonight.

Green, the apparent frontrunner for Alexander's job, is dean of urban affairs programs at Michigan State University. From 1973 to last year he served as dean of MSU's College of Urban Development, a small undergraduate program with about 120 students and eight professors. Edward Zabusky, director of the Michigan State news bureau, said the college was abolished because of budget cuts.

Green also served as education director of the Southern Christian Leadership Conference and has been a strong advocate of busing for school desegregation, as a witness and consultant in several major desegregation cases, including Chicago.