Updated ground motion spectral matching requirements in the 2015 NEHRP recommended seismic provisions
The Building Seismic Safety Council (BSSC) recently completed a multi-year effort to rewrite Chapter 16 of the ASCE/SEI 7-10 Standard (2010), which governs ground motion selection and modification for new building projects in the United States. This paper provides an overview of new recommended provisions regarding the use of spectral matching of ground motions. Example analyses of three buildings are shown to illustrate the reasoning behind the spectral matching language, and to demonstrate the relative differences in response estimates obtained from scaled versus spectrally matched motions. For these examples, the demands placed on the buildings by spectrally matched motions developed using the recommended provisions were comparable to the demands produced by amplitude scaled motions. The consistent demands produced by the procedures suggest that evaluations of a building design’s acceptability are comparable whether scaled or spectrally matched motions are used. The revised provisions should significantly advance the practice of ground motion selection and modification in the United States and elsewhere, by aligning practice with research outcomes.