If the "Big One" rocks San Francisco, as predicted, at least there could be some lessons learned about high-end earthquake engineering. That's thanks to a monitoring project, launched today, that involved installing seismic monitors on the South Tower of One Rincon Hill. The 641-ft-tall residential tower is of interest to the seismic design community not only because of its height—it's among the tallest residential towers west of the Mississippi—but because it is the tallest building in the U.S. built using performance-based seismic design (PBSD) to meet (or exceed) the prescriptive code. The approach, pioneered in San Francisco by structural engineer Magnusson Klemencic Associates, can provide the opportunity to improve architecture, save on cost and simplify construction compared with a building that follows the standard code.
The monitoring project is a joint effort of the U.S. Geological Survey and the California Geological Survey. The collaboration has resulted in the densest array of seismic instruments in any skyscraper in the U.S., say the two entities. They add that many dams, bridges and low-rise buildings are instrumented but not too many skyscrapers. They hope to change that with more instrumentation projects.
If anyone is curious, data from other instrumented structures, including the Golden Gate Bridge, can be viewed at the website of the Center for Engineeering Strong Motion Data.
Structural engineers are very interested in One Rincon Hill's behavior in an earthquake because there has not been a strong temblor in the U.S. since the introduction of PBSD in the U.S., about a decade ago.
Scientists say that there’s a 63% probability of a damaging earthquake —magnitude 6.7 or greater—in the next 30 years in the Bay Area. So, when the Big One hits, let's hope the data from One Rincon Hill will show proof of concept.