A study on the connection effects of subsurface slabs to exterior walls inthe KNGR seismic analysis

The soil-structure interaction (SSI) analyses are being performed for the K orean next generation reactor (KNGR) design, because the KNGR is developed as a standard nuclear power plant concept enveloping various soil condition s. The SASSI program, which adopts the flexible volume method is used for t he SSI analyses. Since the impedances are computed based on the assumption of a rigid foundation in the KNGR design, the impedances are computed at a single point around the center of the basemat. The base model used in the S SI analyses assumed that the subsurface slabs are free and not connected to the exterior walls. This results in a more flexible structure than reality . This study is performed to address the concern of the potential dynamic e ffect of this modeling assumption on the overall structural response. The s uper-structure model is modified with the subsurface portions of the sticks being laterally rigid, so that the entire subsurface cavity together with the super-structure model acts laterally rigid. For the comparison, the in- structure response spectra using the rigid subsurface model are compared wi th the original spectra without considering the connection effects. (C) 200 1 Elsevier Science B.V. All rights reserved.