PRIMARY STRUCTURE, Willis Tower, posted by Mattias Vandenbempt at 06.03.18, filed under: steel, STUDIO: , Location: 233 S Wacker Dr, Chicago, IL 60606, USA, back-button PRIMARY STRUCTURE, Willis Tower, posted by Mattias Vandenbempt at 06.03.18, filed under: steel, STUDIO: , Location: 233 S Wacker Dr, Chicago, IL 60606, USA, back-button
fig 270A,
fig 270B,