The Olmsted Building, the 14-story high-rise under construction in Arlington's Clarendon area that was damaged by fire in July, is expected to open in late December, only a month behind schedule, an official of the firm that owns it said last week.

Although county fire officials originally estimated $750,000 in damages to the $30 million office and retail building, a spokesman said last week that the figure has been revised to reflect the $350,000 estimate made by the building's owner, the Clarendon Metro Limited Partnership. The building is at Wilson Boulevard and North Highland Street.

William M. Cramer, executive vice president for the partnership, said last week that damage was contained to the top two stories, with most of it occurring at the 13th level, where two-thirds of the floor had to be replaced. Cement for the floor of the 14th story had been scheduled to be poured the morning after the July 25 fire, so only the pillars and steel beams at that level had to be replaced, Cramer said.

Fire officials still have not determined the cause of the spectacular blaze, which broke out shortly before 1 a.m.

Misdemeanor charges have been filed against the two companies involved that day in the building's construction, and against their foremen, because of alleged violations of the state building code that hampered firefighters' efforts to extinguish the blaze.

Firefighters arriving on the scene said they were delayed because an illegally parked dumpster blocked their access to a ground-level water pipe, and because another water pipe inside the building was several stories shorter than required. Firefighters had to hand-carry hoses up the stairs.

The Richmarr Construction Corp. and its foreman, Ronald Wood, could be fined $1,000 apiece on each of those charges if convicted. The Beiro Concrete Co., and its foreman, Dave Harvey, each faces one misdemeanor charge in connection with the allegedly blocked ground pipe.

Jerry K. Emrich, an attorney representing Richmarr and Wood, said his clients will enter pleas of innocence. Waller T. Dudley, the attorney for Beiro and Harvey, said no decision has been made on a plea.