A $23.2 million contract for initial work on a new stadium for the Washington Nationals will go to a joint venture of three firms. The District of Columbia Sports and Entertainment Commission announced Friday its board of directors approved plans to hire the consortium of Clark Construction, Hunt Construction Group and Smoot Construction. The commission said the trio has worked on 15 other ballparks for Major League Baseball. Ten of those had HOK Sport as the architect. HOK is part of a separate architectural joint venture in the Washington stadium.