In May 2010 I performed an exercise in do-it-yourself seismic screening of an existing building.
I used 2 methods: FEMA 154 and P25. These methods are both intended for a broad class of users, such as building owners. One term used to describe such methods is “rapid visual screening”. The idea is that people can estimate the likely performance of their building in a major earthquake and then make an informed decision on whether to invest in a professional seismic assessment of the building.
These methods are somewhat difficult to apply, because they require classifications that are not clearly defined. Since performing the exercise, I have not detected any progress in the availability to the public of well-documented, easy-to-apply do-it-yourself seismic screening tools.
I discussed this problem with some engineers at the 2011 PEER Annual Meeting. Some are working on new and better screening methods. One engineer referred me to the ASCE 31 standard for the seismic assessment of existing buildings. Its current version, ASCE 31-03, was published in 2003. It defines 3 “tiers” of seismic assessment. In 2008 it was critically reviewed by 3 engineers, who argued that it has fundamental defects and will be “promoting the expenditures of large sums of money on inappropriate engineering analysis”. Whether it is a worthy method or not, it does not seem to be a method designed for the owners or users of buildings who wish to perform do-it-yourself screenings. For example, let’s assume that I have correctly classified Berkeley Town House’s building as a C2 building. Then the Tier 1 checklist for this building requires me to decide whether the building complies with this criterion: “The stiffness of the lateral-force-resisting system in any story shall not be less than 70 percent of the lateral-force-resisting system stiffness in an adjacent story above or below, or less than 80 percent of the average lateral-force-resisting system stiffness of the three stories above or below for Life Safety and Immediate Occupancy.” Decisions like this can’t be read straight off the building drawings.
Life (for those surviving) after a major earthquake will also depend on the entire region’s response. For those in the Bay Area, one of the talks at the PEER meeting gave a forecast of this. You can watch Janielle Maffei’s talk on “The Coming Bay Area Earthquake—2010 Update” to learn more about the expected damage and the recent efforts to mitigate it in advance.