NEW YORK, May 2--Columbia University's administration yesterday made three concessions to mounting student-faculty pressure, as all classes remained closed for the third day. Eleven of the University's 13 divisions will suspend classes until Monday.

New York policemen, who had occupied the University since Tuesday, were removed from the campus proper. They remained, however, at all the entrances to the campus, admitting only those with proper identification.

The Board of Trustees appointed a special committee of Board members "to study and recommend changes in the basic structure of the University." They also requested that a similar study be made by the Executive Committee of the Faculty, an ad hoc group of about 500 faculty members who have expressed their disagreement with the proposed student strike.

The Board also announced its "intention that consultants and negotiations with community leaders shall be held before a decision is reached as to whether or not construction of the gymnasium will be resumed."

Strike Planned

The Trustees requested all students and faculty to resume their scholarly activities. "It is expected that the Trustees' declaration will not disuasde the students and faculty now planning to go on strike from carrying it out," The Columbia Daily Spectator reported yesterday.

Support for the proposed strike expanded yesterday to include groups from all political positions. At a meeting late Wednesday night, more than 1300 students voted to form a new Strike Steering Committee keeping the old 11-man steering committee as a nucleus.

Groups wishing to support the strike are receiving one delegate on the new Steering Committee for every seventy people the group represents. The new Steering Committee, which met continuously yesterday afternoon and evening, had about 30 members by late last night.

Moderate Petition

A petition requesting that classes be resumed Monday was circulated yesterday afternoon by a group called "The Moderate Middle." It received approximately 500 signatures. The University includes approximately 17,000 students.

About 200 of Columbia's 700 faculty members have signed a petition of support for the proposed strike. These faculty members informally conducted about 75 "liberated classes" on the lawns and steps of Columbia.

During the day, 25-40 special groups also held meetings. The groups ranged from The Alumnae Committee for Fair Play to Strikers to the Committee for the Defense of Property Rights, which claimed it had sold more than 700 "Stop SDS On Campus" buttons in the last week.

Faculty Committee

Columbia's Faculty Committee on Instruction, which controls the University's academic structure, met in special session yesterday. Their recommendations were not revealed. However, sources indicated the Committee was considering a proposal to allow all students to receive a "pass" for the term's work. Under this procedure, students would not have to take final exams, and the student body effectively would be dismissed until September.