SITE RESPONSE ANALYSES

摘要

The subject of development of site specific performance-based design motion and its application to soil-structure interaction (SSI) analyses has been discussed in a number of guidance documents developed for both the Nuclear Regulatory Commission (USNRC) and Department of Energy (USDOE). NRC's Regulatory Guide 1.208 and upgrade to Sections 2.5.2, 3.7.1, 3.7.2 and 3.7.3 of NRC's Standard Review Plan (NUREG-0800) and DOE Standards (DOE Std 1020-94) have emphasized probabilistic approaches to development of seismic hazard and site response. These procedures are now used to estimate seismic response of critical facilities for design and evaluation purposes. Chapter 2 of the new revision of ASCE 4 attempts to captures all significant changes to the recommended site response analysis procedures with the goal of providing an industry consensus on this process. This paper summarizes the interpretation of the regulations and guides, and the industry agreement on the details of the development and application of the ground motion for SSI analysis. The objective of the recommended methodologies is to maintain consistency from development of the design motion from site response analysis to its application to SSI analysis and evaluation of results. Consistent use of soil property data and input motions developed based on the recommendations in Chapter 2 of ASCE4 for application to SSI analyses described in Chapter 5. Issues currently being emphasized in probabilistic site response analyses include (a) development of Foundation Input Response Spectra (FIRS) to be used as input to deterministic SSI analyses, (b) development of appropriate description of nonlinear soil properties to accommodate the incorporation of nonlinear behavior in the site response evaluation, and (c) consideration of layer-to-layer velocity correlation models in the column realizations