Sigma provided the analysis and the preparation of the engineered demolition plan for PG&E’s Hunters Point Power Plant in San Francisco, California.  Footage is available on our YouTube Channel.

The power plant was originally constructed circa 1928 at Hunters Point at the edge of the San Francisco Bay.  The original structures were comprised of lightly reinforced concrete buildings, and riveted structural steel frames.  Large scale expansions later included in the construction of heavy rolled steel I-members that supported high pressure steam units adjacent to the original 1928 construction.

Sigma’s services included the preparation of design calculations, demolition procedures, and on-site observation of large scale demolition activities for the demolition of two 120’ tall steel frame steam units, the removal of a 100 tall double steam unit and concrete building enclosure and a 120’ tall steel chimney.

Sigma worked closely with ground crews from LVI Environmental Services to safely prepare and remove large segments of the interior steel members and associated mechanical works.  Sigma also worked with members of Controlled Demolition Inc, (CDI), to develop a removal strategy for the two boiler frame systems, building segment, and chimney section by controlled explosives charges.

All large scale elements were successfully removed using controlled explosive demolition techniques while being located as close as 25 feet away from the environmentally sensitive San Francisco Bay.  These unique demolition techniques resulted in zero splash in the bay and no damage to the active switch yard located only 150 feet from the structures demolition zone.