Sigma was the engineer of record, and is presently involved in the conventional demolition of the 26 story McGuire building, located in downtown Seattle, WA. This project involves the demolition of a post-tensioned concrete slab building, including a complex removal scheme, piece-by-piece removals, and use of a tower crane to lower building segments to the ground. Sigma provided engineering of demolition plan as well as tower crane foundation design, and man-lift engineering support.