Aecom Technology Corp. has acquired Tishman Construction Corp. for $245m, in a deal that combines one of the world's largest engineering and design firms with the storied New York-based construction business. The companies have overseen some of the world's largest complex construction projects. Los Angeles-based Aecom is currently working on New York City's new Second Avenue subway and Saadiyat Island, a $30bn development off the coast of Abu Dhabi.