California’s tallest residential-only tower and, according to some, the ugliest building in San Francisco has been given a new purpose following the installation last month of 72 accelerographs, or strong motion seismographs, within the building. Through a collaboration between the California Geological Survey, the U.S. Geological Survey, and Madnusson Klemencic Associates, the building’s structural engineers, the 641-foot southern tower of the One Rincon Hill luxury condominium development at the base of the Bay Bridge is now home to the “densest network of seismic monitoring instruments ever installed in an American high-rise,” the San Francisco Chronicle reported. These instruments, located at strategic points throughout 24 floors of the building, will provide “unprecedented” seismic data, which will in turn lead to better building codes and guidelines for structural engineers and future high-rise builders.
Designed by Solomon Cordwell Buenz of Chicago and completed 2009, One Rincon Hill has been a target of architectural debate since before it was completed, but its merits as an earthquake-resistant piece of engineering have never been doubted. While the building resembles an Ionic Breeze air purifier from Sharper Image (the project was originally intended to serve as the company’s headquarters before financial problems befell them in 2005), it is outfitted with cutting-edge engineering, some of which is being used for the first time ever in the United States. Equipped with a ductile concrete core, a steal outrigger column system, buckling restrained braces, and a 54,000-gallon water tank at the top to counter the sway of the wind, One Rincon Hill is prepared to withstand an earthquake of 6.7 or greater. Which is good, since experts predict that there is a 63% chance of a quake of that magnitude occurring in the Bay Area in the next 30 years.
The building’s location, height, and structural integrity together provided for a nearly ideal home for the largest collection of seismic sensors found in any California high-rise. These instruments, housed in small black boxes, are constantly operating, and will measure the buildings movement, both horizontal and vertical, up to a thousandth of an inch. In the case of a significant earthquake of a magnitude of 3 or higher, the data from the sensors will be transmitted immediately to state and federal scientists in Sacramento and Menlo Park to be analyzed. Anthony Shakal, head of the California Geological Survey’s Strong Motion Instrument Program expects the devices will help design safer buildings and hopes to install similar devices on tall buildings and other structures, collecting a wealth of information to assist in preventing future seismic disasters.