One Rincon Hill anchors the redeveloping neighborhood of Rincon Hill in San Francisco, California. The all-residential tower is located on a narrow site just eight miles from the San Andreas Fault. In response to being built in this highly seismic region, the project employs a first-of-its-kind structural system, using a nontraditional Performance Seismic Design approach (PSD), the first ever to be approved in California.

This structure features a concrete ductile core wall and four concrete outrigger columns connected by buckling restrained braces. The PSD design eliminated the need for an exterior moment frame which reduced overall cost by 8%, increased individual unit areas, allowed unobstructed views, shortened construction time, opti-mized material quantities, and enhanced performance.

Another first in this project is the tuned liquid-mass damper, the first to be employed in the U.S. Two 54,000-gallon tuned liquid sloshing damper tanks located at the building’s top use the motion of sloshing water to counteract wind accelerations and increase occupant comfort.

Throughout the design development process the structural engineer undertook two different research projects. The first project focused on link beam connections at UCLA (with Charles Pankow Foundation and Webcor Concrete). The other studied post-tensioned slab/wall connections at UC Berkeley. The efforts improved One Rincon Hill’s design, led to a modification of ACI Code 318-08, and will influence future design and construction practices.