Washington Hospital Center registered nurses voted overwhelmingly yesterday to end their 31-day-old strike against the area's largest private hospital.

The contract the nurses voted 181 to 12 to accept was the same offer their bargaining committee had rejected out of hand last Wednesday. The following day the Hospital Center announced it was "finished negotiating" and said it was seeking to hire permanent replacements for the approximately 250 striking nurses.

"We're ecstatic," said Ann Hartzel, spokeswoman for the District of Columbia Nurses Association, which represents the striking nurses. "They've given in on a lot of things and we've proven a lot of things.

"We've proven a lot of things to ourselves and the Hospital Center and the community. We've proven that we can organize, that we're unified, and much more than anything else, we've built a union and we're going to continue the union," she said.

Ironically, although the nurses main demands involved items affecting nurse autonomy and control of nursing, and money was never an issue, the new contract gives the nurses virtually no more autonomy and control than they had 32 days ago while guaranteeing them the highest wages in the city.

The contract approved by the nurses yesterday gives them a 6 percent raise now, for a starting salary of $13,384 for a nurse with no experience, and a top of $18,917.28, for the most experienced head nurse on a unit.

On June 18 of next year the nurses will receive another 6 percent raise, increasing the starting salary to $14,187 and the top to $20,052.

By comparison, an inexperienced nurse starting work at Georgetown University Medical Center July 1 will earn about $12,480 a year. It is extremely difficult to compare the top categories because of differences in categorization of nurses at the two hospitals. Under the new contract, however, the Hospital Center will be paying more than the other hospitals at the top end as well as the bottom of the scale.

Among the key items the nurses failed to win were:

A union shop. Instead, the Hospital Center agreed that anyone belonging to, or voluntarily joining, the union after July 15 must remain in the union. A Hospital Center contract offer rejected by the union on June 14 would have required that anyone who was a union member as of June 14 would have had to remain in the union.

Permanent day shifts for any nurse with five years or more seniority requesting the assignment. Instead the Hospital Center agreed, as long ago as June 14, to establish a joint nurse-management committee to study the matter and implement a plan of action by Jan. 1.

Seniority based on length of employment at the Hospital Center. The hospital agreed to that as it applies to layoffs, but not as it applies to transfers from one unit to another, or to promotions within units.

The right to arbitration of disputes involving performance ratings. The nurses did, however, win the right to have other grievances arbitrated.

The net effect was, according to Hartzel, that now a nurse "can't take to grievance a bad performance rating but . . . can add things to it and take all of them together to arbitration."

The Hospital Center contended all along that it would never give in on those items because it maintained that they effect patient care.

Center officials argued that allowing a union shop would affect patient care because it would remove from the hands of the hospital's board of trustees at least some of the control over the practice of nursing in the hospital, vesting that control in the hands of the union which has no legal or, the officials contend, moral responsibility to the hospital's patients.

Although the 31-day strike by 60 percent of the hospital's staff nurses did not result in the hospital capitulating to their main demands, the nurses did win union dues check off, an extra holiday, a doubling of life insurance coverage, maternity leave, an increase in educational benefits and a slightly improved sick leave plan.

Hospital Center spokeswoman Jane Snyder said the hospital's board of trustees will vote on the contract Wednesday afternoon. The vote to approve is expected to be pro forma, she said, as the board had already approved of the offer made to the nurses.

Snyder said the nurses will be called back to work as the hospital reopens units closed during the strike. The strike has been a situation "in which nobody really wins," she said. Both the nurses who struck and those who worked, "proved they're care givers. Now they're going to have to prove they're peace makers. That's the next big challenge.