[en] The aim of this analysis is to reduce the dynamic response of a structure. The seismic isolation solution must take into consideration the specific site ground motion. In this paper will be presented results obtained by applying the seismic isolation method. Based on the obtained results, important conclusions can be outlined: the seismic isolation device has the ability to reduce seismic acceleration of the seismic isolated structure to values that no longer present a danger to people and environment; the seismic isolation solution is limiting devices deformations to safety values for ensuring structural integrity and stability of the entire system; the effective seismic energy dissipation and with no side effects both for the seismic isolated building and for the devices used, and the return to the initial position before earthquake occurence are obtained with acceptable permanent displacement. (authors)

[en] Published in summary form only

[en] In this study, the analysis of the effects on the floor response spectra by the nonlinear behavior of a seismic base isolation system was performed. The nonlinear behavior was defined as the ratio of stiffness and the effect of bi-direction. FRS(The floor response spectra) depends on the characteristics of the seismic base isolation system such as the natural frequency and damping ratio. An evaluation of the seismic isolated structural integrity, using the equivalent stiffness of the seismic base isolation system was satisfied. However, a FRS of seismic isolated structure is greatly changed because of the nonlinear behavior of seismic isolation system. Therefore the generating of FRS for seismic isolated structure, more researches are needed about nonlinear behavior of seismic isolation system. In this study, the analysis of the effects on the floor response spectra by the nonlinear behavior of a seismic base isolation system was performed. The FRS was increased in hi-frequency domain because the influence by the nonlinear behavior of isolation system. In addition, each floor exhibited a more different of responses compared with the equivalent linear model of the seismic isolated structure. The nonlinear behavior of the seismic isolation system was considered, because of a more reliable assessment of integrity about equipment at each floor of seismic isolated structure

[en] SCHENBERG is a resonant-mass gravitational wave detector with a frequency about 3.2 kHz. Its spherical antenna, weighing 1.15 metric ton, is connected to the external world by a system which must attenuate seismic noise. When a gravitational wave passes the antenna vibrates, its motion is monitored by transducers. These parametric transducers uses microwaves carried by coaxial cables that are also connected to the external world, they also carry seismic noise. In this analysis the system was modeled using finite element method. This work shows that the addition of masses along these cables can decrease this noise, so that this noise is below the thermal noise of the detector when operating at 50 mK. (paper)

[en] A Friction Pendulum System (FPS) is a well known seismic isolation system. In the case of FPS, the period of a vibration only depends on a radius of a curvature and the gravitational constant, and it does not depend on the mass. For this reason, the FPS is useful for smaller weight equipment and a liquid storage tank which changes its' liquid level. Kim et al. (2004) studied the seismic isolation effect of small equipment by using a natural rubber bearing (NRB), a high damping rubber bearing (HDRB) and a Friction pendulum system (FPS) by an experimental research. In this study, modified Mokha model for a small FPS system was proposed and it was revealed this model matched the experimental results well

[en] Nonlinear hysteretic behaviors and stiffness changes of a seismic isolator are identified by using a Time Domain System Identification (TDSI) based on the secant stiffness model. A new regularity condition of tangent stiffness used in the current TDSI is proposed instead of that used in the conventional Duhem hysteretic operator. The proposed regularity condition is defined with respect to time while that of Duhem hysteretic operator is defined with respect to displacements and restoring forces. The secant stiffness model for the TDSI is obtained by approximating the tangent stiffness under the proposed regularity condition by the secant stiffness at each time step. A least square method is employed to minimize the difference between the calculated response and measured response for the time domain system identification of the secant stiffness. The regularity condition of the secant stiffness is utilized to alleviate ill-posedness of the TDSI and to yield physically meaningful solutions by means of the regularization technique. An optimal regularization factor determined by Geometric Mean Scheme (GMS) is adopted to yield appropriate regularization effects on the system identification. The validity of the proposed method is presented through two numerical examples

[en] Highlights: • Lists implementations of seismic isolation of nuclear facilities in Europe. • Compiles and distils information on seismic isolation in the modern era. • Identifies recent developments and best practice in seismic protective systems. • Identifies future opportunities and technical needs. - Abstract: Seismic isolation of nuclear power plants is in its infancy, with only a small number of applications worldwide. This outcome is due in part to the construction of only a small number of new build nuclear power plants since base-isolation technology became mainstream in the 1990s, perceived concerns regarding the long-term mechanical properties of isolation bearings, and a lack of guidance, codes and standards related to isolation of safety-related nuclear facilities. This paper charts the history of seismic isolation, identifies the research that led to the first implementation of isolation for buildings and bridges in the modern era, summarizes the first applications of the technology to nuclear facilities, and describes important research and developments, including the writing of nuclear standards, in the past 20 years. Future research and development needs are identified.

[en] In order to examine the operability and the structural integrity of the isolating valve of containment under the seismic and remote load condition, the seismic and remote loading test for the isolating valve was conducted on the 6 m × 6 m seismic table. The multiple-frequency seismic qualification test shall be completed on the axis of X, Y, Z during the seismic test. The acceleration and strain response values of the isolating valve under OBE and SSE level were measured. The maneuverability of the isolating valve on seismic text and after seismic test was verified. Then, the remote load was exerted on the isolating valve, while the valve maintains its inner pressure. The maneuverability of the isolating valve under remote load and self-weight and working load was verified. The seismic and remote load test shows that the isolating valve of containment kept its structural integrity and operability under the seismic and remote load condition. (authors)

[en] The seismic qualification process for systems and components entails seven steps. These steps apply whether the task at hand is the design and qualification of a new system, or the seismic retrofit of an existing system. The seven steps described in the paper are: definition of scope and function; seismic input and concurrent loads; methods of qualification; assessment of interaction; documentation; configuration management; and, periodic inspections

[en] In recent years, seismicity has been increased several times in the Russian Federation. The situation exerts a significant effect on the seismic resistance of existing facilities. It is known that buildings can be reinforced by using various methods among which unconventional seismic protection devices that include seismic isolation and seismic damping hold a special place, being efficiently used not only in newly built buildings, but also in operated ones. Unconventional methods implementation of the seismic resistance increase in operated buildings is shown using specific examples. Rubber-metal supports, dynamic absorber and rubbing friction dampers are used. Recommendations on their specific use to improve buildings seismic resistance are offered. (paper)