Fort Lewis stacks,
Buildings 3452, 3929 and 9580
Owner: Fort Lewis
ABC member: United Rentals
Taking down four structurally compromised stacks, some as high as 180 feet, in close proximity to both highly combustible materials and functioning buildings required significant project and safety planning, as well as substantial engineering.
The Fort Lewis stacks project started with the collaboration of Nuprecon and engineering experts to design a safe and innovative solution to remove the two rusting steel stacks and two breached concrete stacks. The answer was to use a series of self-supporting crane "track" systems equipped with motorized scaffolding that ran the height of the stacks.
The first two stacks, made of now-rusting steel, were 60 and 120 feet high. Their weakened state eliminated the possibility of lowering them to the ground with a crane. Also, both were sandwiched between 13 gas lines and a 10,000-gallon fuel tank feeding the active facility.
The final two stacks were built of concrete and stood over 180 feet tall. These stacks required an additional vertical support track due to their diameter and height. Also, the volume of material generated during the demolition of the concrete stacks was much higher than the steel stacks, requiring additional safety precautions. Using the stack itself as a debris-shaft, Nuprecon cut and structurally supported a small hole in the base of each shaft, which was in the basement of its host building, for debris load-out.
Nuprecon completed this Department of Defense project without a single safety incident and on budget.