Seismic response of electrical cabinets considering primary-secondary structure interaction with contact nonlinearity of anchors

Seismic assessment of safety-related equipment in a Nuclear Power Plant (NPP) is more demanding compared to general structures owing to their role in the safe operation and shutdown of the plant. In-cabinet response spectra (ICRS) is thereby generated to qualify the performance of the sensitive devices installed in a cabinet. This study presents the effect of post-installed anchor interaction on the seismic response of an electrical cabinet to drive the ICRS considering primary-secondary interaction (PSSI). Nonlinear hysteretic shear behavior of the anchor connection and its interaction with the floor was considered. An equivalent numerical model was developed to imitate the nonlinear behavior of the anchor bolt. The numerical behavior of anchor was validated using the recent available experimental results. A parametric study for the coupled and uncoupled condition was also considered. The seismic response manifests the nonlinear interaction of anchor bolt that is significant to be considered. The response amplification in a coupled system with anchors nonlinearity is more significant than the floor response spectra (FRS) method and the fixed boundary condition. Moreover, for tuned and nearly tuned primary-secondary systems under the linear and nonlinear connection is also addressed.核电站（Nuclear Power Plant, NPP）安全相关设备的抗震性能评估相较于一般建筑要求更为严苛，原因在于此类设备关乎核电站的安全运行与停堆。因此需生成柜内响应谱（In-cabinet Response Spectra, ICRS），以验证安装于机柜内的敏感设备的性能表现。本研究聚焦后装锚栓相互作用对电气机柜抗震响应的影响，通过考虑主次结构相互作用（Primary-Secondary Interaction, PSSI）推导柜内响应谱。研究中考虑了锚栓连接的非线性滞回剪切特性及其与楼板的相互作用，建立了等效数值模型以模拟锚栓的非线性力学行为，并通过最新公开的试验结果对锚栓的数值模拟行为进行了验证。此外，本研究还开展了耦合与非耦合工况下的参数化分析。抗震响应分析结果表明，锚栓的非线性相互作用影响显著，必须予以考虑。考虑锚栓非线性的耦合系统中，响应放大效应相较于楼板响应谱（Floor Response Spectra, FRS）方法与固定边界条件更为显著。同时，本研究还针对线性与非线性连接工况下的调谐及近调谐主次结构系统的响应特性展开了探讨。