Soon after Fairfax County officials broke ground on a new courthouse in 1979, the problems began: Workers dug holes for the building's concrete support pilings in the wrong places, pile driving equipment operators staged a 21-day strike, and rain temporarily stopped work.

Altogether, more than 250 requests were made by the county or Equitable Construction Company Inc., the prime contractor, to substitute building materials, use additional labor or modify the design of the building. The 23 changes Equitable and the county have agreed upon so far have cost an additional $500,000, said John W. di Zerega, director of the county's office of capital facilities. The possible price of the more than 225 other changes still is undetermined, county officials said.

The costly changes and construction delays that put the project more than a year behind schedule during inflationary times already have resulted in one lawsuit and are expected to bring hundreds of thousands of dollars in other court claims among Fairfax, Equitable and half a dozen subcontractors. The five-story building, which was supposed to open in March 1981, is now expected to open in September or October.

"The possibility exists that lawsuits over this project could go to the million dollar range," said di Zerega. "We have some claims and the contractor has some claims. When it's all over a lot of lawyers around here are going to be very well off."

The disputes over the center, which was originally expected to cost $15.3 million, have caused cautious county officials to hire a team of construction litigation experts from the Washington law firm of Walstad, Kasimer, Tansey and Ittig in anticipation of further claims. Any awards against Fairfax would have to be paid out of the county's general fund, county officials said.

The only suit so far is a $334,523 claim filed by Northern Virginia Steel Corp. against Equitable and Aetna Casualty & Surety Company. Northern Virginia Steel held a $2 million contract with Equitable to perform subcontracting work on the judicial center.

In papers filed in Fairfax Circuit Court on March 31, the steel company said it had expected to finish its work by December 1979. However, Northern Virginia Steel claims it was delayed by Equitable "in completing its performance of labor and furnishing of materials . . . and thereby incurred additional costs and expenses."

An official at Aetna, the firm which insures that work is adequately completed as agreed, downplayed concern about possible litigation and said the pace of construction has not caused any alarm at his company.

"Equitable is no worse than anybody else we've dealt with," said Roger Albardier, manager of the bond department in Aetna's McLean office. "In nine out of 10 construction projects you have some delay . . . Unless there's a pattern of widespread unpaid bills, you don't get excited about it."

"As a taxpayer I don't like these claims," Albardier said. "But I'm afraid that's life. When you get misunderstandings, you get lawyers and lawyers cost money."

"We have turned the building over to the county," said Thomas Maichak, president of Equitable. "None of the construction problems were out of the ordinary."

Located near the 12-story county administration building, the new courthouse in Fairfax City near Rte. 236 and Rte. 123 seems an unlikely target for litigation. Officials close to the project agree that workmanship on the building is sound and its computer technology and security systems state of the art.

J. Richard Tremaine, an assistant county attorney, said legal disputes over the judicial center probably could be avoided if state law did not prohibit the county from resolving claims through binding arbitration.

The problems plaguing the new judicial center also are creating some troubles for Fairfax's Circuit Court judges, who would hear court cases that result. Many of them campaigned in 1977 for a $18.7 million bond referendum to finance the judicial center after complaining that the old courthouse on Chain Bridge Road and Rte. 236 had poor security and was too small to handle the average of 1,300 cases filed each year.

Some judges are not enamored with the prospect of hearing lawsuits over a center they supported. "I personally would have problems with it hearing cases relating to the center ," said one Fairfax Circuit Court judge who asked not to be named. He said judges would probably have to be brought in from elsewhere to handle the suits.

"I'm frankly not surprised by the long time it's taken to complete that building," said retired Fairfax Circuit Court Chief Judge Arthur W. Sinclair, who still hears area cases occasionally. "Public buildings always seem to take a long time to construct . . . This one seemed like it had trouble from the start."