Evolution of a tower crane

28-Feb-13 – A few weeks late but on the job every day until Tuesday’s snowstorm in downtown Chicago, the upwardly-mobile tower crane at 111 West Wacker is seen on February 12, 19, 24 and 26. The foundation of the tower crane, viewed from Marina City in the first image, is not going anywhere anytime soon as it is buried in a concrete platform five feet thick. Two steel beams then transfer the load to one of the building’s columns.

The 60-story luxury residential tower should be completed in the spring of 2014. (Photos by Steven Dahlman. Click on images to view larger versions.)