Concrete workers from locals 6A, 18A and 20, including workers on the World Trade Center site and Weill Cornell Medical College research center, returned to work Aug. 4 following a three day strike that began Monday. The unions have agreed to extend their contract, which expired on July 29, to August 16, says Louis Coletti, president, Building Trades Employers’ Association. However, an agreement has not yet been reached on new terms including a proposed 20% wage cut.
 
Separately, independent arbitrator Richard Adelman said on Tuesday that Concrete Workers District Council Local 16, an umbrella union group that also had some walkouts on Aug. 1, was in violation of a no-strike clause on four projects -- Barclays Center in Brooklyn, Madison Square Garden, 2 WTC and a residential tower on West 57th St. Adelman ordered the workers back to these sites on Aug. 3.
 
Calls made to locals 6A, 18A and 20 were not returned by press time. Concrete Workers District Council Local 16 had no comment.