GRANDAWARDS ACEC 201 8 ENG I NE E R I N G EXCE L L E N C E AWA R DS 150 North Riverside Chicago, Illinois Magnusson Klemencic Associates Seattle, Washington A dazzling example of superstructure design, this new 54-story office building has transformed a previously barren, undeveloped site into a vibrant public complex. To overcome extremely tight site constraints, the project team developed a cutting-edge, blade core design that requires half the support pilings of a comparable building. At 750 feet, the 1.25-million-square-foot tower balances atop a base that is only 39 feet wide. Twelve water tanks at the top of the building contain 700 tons of water to help minimize building sway in strong wind conditions. A precast, prestressed concrete lid atop nearby railroad tracks provides space for a new public park featuring an amphitheater, pedestrian pathways and retail venues. 18 ENGINEERING INC. MAY / JUNE 2018