PHILADELPHIA The 18-story city office building at the foot of the Benjamin Franklin Parkway, formerly the headquarters for Bell Telephone Co. of Pennsylvania, will be closed through the weekend as contractors try to repair the building's elevators, damaged by water from a broken pipe.

Mayor Nutter said Wednesday that the 1,900 workers assigned to various departments inside the building should check with their supervisors to see if they should report to alternate work locations for essential services Thursday. The building was already to be closed on Good Friday.

The building houses the Department of Human Services, Law Department, Parks and Recreation, the Planning Commission, the Commerce Department, the Board of Ethics, the Greater Philadelphia Film Office, and other agencies.

A hot-water pipe on the fifth floor broke Tuesday evening, setting off a smoke alarm and "frying" the electronics of all eight elevators as water cascaded down nearby shafts, according to Bridget Collins-Greenwald, the city's public property commissioner.

She said contractors expected to repair the damage Thursday and Friday, and would work through the weekend if necessary so the building could reopen Monday.

Several city agencies, such as the Zoning Board of Adjustment, had scheduled public meetings Wednesday but made arrangements to move them to other city buildings nearby.

Nutter told reporters that the Human Services Department had already put in place contingency plans to continue its essential operations at other sites.

He scoffed at a suggestion that city employees might use the building's stairways to continue working without elevator service, calling it "a disaster in the making" if a fire or other problem necessitated evacuation.