On Friday, Emanuel announced the city was in talks with a joint venture led by multinational engineering and design firm AECOM to design and build the $95 million building. By heralding such an incremental step in the process, he was able to make it clear he plans to move this signature project toward completion before he leaves office in May. And he could help assuage the concerns of his City Council ally, Ald. Emma Mitts, 37th, that the development she believes will be an anchor for her struggling ward won’t get left by the wayside when Emanuel departs.