Consistent site-response/soil-structure interaction analysis and evaluation

The subject of development of site specific performance-based design motion and its application for soil-structure interaction (SSI) analysis has been discussed in several regulatory guides and standard review plans and other standards including RG 1.208, RG 1.60, SRP 2.5.2, SRP 3.7.1, SRP 3.7.2, ASCE 4-98 and ASCE 43-05 in USA. More recently, the Nuclear Regulatory Commission's Interim Staff Guidance (draft ISG-017, 2008) describes the use of various site-specific ground motions for structural analysis and evaluation. Following this ISG, the industry group formulated an approach for development of the design motion from site-response analysis and its consistent application for SSI analysis. This approach was subsequently accepted by the NRC (ISG-017, March 2010) and is currently used by most applicants for licensing of the new plants. In this paper the details of the methodology commonly known as the “NEI Approach” and used by many applicants is presented and its use for the standard plants are described.