## 1 Introduction  
The application of base isolation technology can prevent building structures from being affected by moderate-to-severe seismic vibrations, enhancing the seismic margin of structures. It has evolved into a relatively mature technology, achieving significant progress during the 1980s and 1990s [1, 2, 3, 4, 5]. The commendable performance of base-isolated buildings during the 1994 Northridge earthquake and the 1995 Kobe earthquake facilitated the widespread dissemination of base isolation technology [6]. In recent years, nuclear power safety and development have become hot topics worldwide. Nuclear power engineering construction faces increasing challenges, with seismic requirements for nuclear power structures continuously rising. The seismic uncertainty of nuclear power plant sites [7], along with the constraints imposed by internal pipelines and equipment on seismic design, presents numerous limitations. However, new development directions, such as the standardization of nuclear power plant construction [8], are also emerging. Base isolation is a crucial technology for protecting building structures against geological disasters. It is not only widely used in civil buildings [9, 10] but has also been applied in operational nuclear power plants [11, 12, 13, 14, 15]. On one hand, it enables nuclear power plants to possess seismic resistance under different peak ground acceleration conditions without altering the superstructure, relying instead on modifications to the base isolation system, thereby reducing the coupling effects on equipment pipelines and components. On the other hand, it contributes to the standardization of nuclear power plant design. However, the application of base isolation technology in the nuclear field is still limited, especially in safety-related structures like diesel engine buildings. If the diesel engine building within the nuclear island is damaged during an accident, losing its role as an emergency backup power source, it could lead to the inability of reactor to continue cooling, potentially causing an explosion. Subsequent accident recovery efforts would also be hindered by the lack of power supply. Therefore, ensuring the safety of diesel engine buildings under extreme seismic conditions and enhancing the seismic margin of the structure are crucial. Research indicates that base isolation bearings are prone to excessive horizontal displacement under high-intensity seismic motion [16], leading to tensile stress in the bearings and causing overturning effects in the structure. This has become one of the main obstacles limiting the application of isolation technology in high-rise structures. In recent years, numerous scholars have conducted extensive research on the tensile stress in bearings and structural overturning issues [17; 18; 19; 20], proposing various bearing optimization methods. In addition to redesigning isolation bearings to address tensile stress and structural overturning, combining isolation devices with different performance characteristics can also improve the seismic performance of isolated structures. Dampers can provide excellent additional damping [21; 22; 23; 24; 25], and when combined with isolation bearings to form hybrid isolation devices, they complement the shear characteristics of the bearings, significantly enhancing the seismic performance of the isolation system. Through comparative case studies, [PERSON] [26] discovered that employing seismic isolators with a vertical frequency of less than 3 Hz can significantly mitigate the vertical response of nuclear power plant structures. However, when the vertical frequency decreases to 1 Hz, it becomes necessary to install anti-sway devices to control the pronounced sway effect. This finding underscores the superiority of three-dimensional seismic isolation over single-level horizontal seismic isolation, offering valuable insights for the seismic design of nuclear facilities. [PERSON] [27] proposed an isolation device composed of friction pendulum bearings (FPBs) and viscous dampers (VDs).