SEISMIC PROTECTION OF LIGHT SECONDARY SYSTEMS THROUGH DIFFERENT BASE ISOLATION SYSTEMS (original) (raw)

The objective of the prgent work is to mine advantages and drawbacks of different types of isolation systems, when seismic isolation is used as a protection strategy against damage to internal equipment and contents. The starting point of the study is the big experimental program of table tests on reduced-scale R/C structural models, carried out within the MANSIDE (Memory Alloys for New Seismic Isolation DEvices) project. Seven identical 133-scaled, bstorey frames were tested, including two fixed-base models and four base-isolated models with different isolation systems, namely: (1) rubber isolators, (2) steel-hysteretic system and (3), re-centring SMA (Shape Memory Alloy) system. In this study the internal equipment is regarded as an elastic single degree of freedom, with 2% equivalent viscous damping. Therefore, the capability of fixed-base and base-isolated models with different isolation systems to protect light secondary systems is evaluated by comparing the floor response spectra obtained from the storey accelerations recorded during shaking table tests. Three different PGA's are considered, about 0.15g, 0.39 and 0.59, respectively. All the shaking table tests are also simulated with an accurate numerical mnodel, to validate and better understand the experimental results. It is found that each type of isolation system reduces considerably the seis mic effects on internal equipments in wide frequency regions. However, tuning effects may arise in specific frequency ranges, corresponding to ,the first mode in structures equipped with quasi-elastic (rubber) isolation systems, and to higher modes in structures equipped with elast-plastic (steel) and nonlinear re-centering (SMA) isolation systems

Application of Two Base Isolation Systems for Seismic Protection of Hystorical Structures Shake Table Test Studies

This paper deals with two base isolation techniques for seismic protection of historical monuments. The effectiveness of these techniques was investigated experimentally on reduced scale models of two Byzantine churches located in Macedonia by shake-table testing at the Dynamic Testing Laboratory of the Institute of Earthquake Engineering and Engineering Seismology in Skopje. The first technique involved base isolation by laminated rubber bearings. Such type of base-isolation was applied on a model of St. Nikita church located in the vicinity of the village of Banjani. The test was realized in the year 2000 within the Macedonian-US Scientific and Technological Cooperation. The second technique involved base isolation by the ALSC floating-sliding system. It was applied on a model of St. Nicholas church located near Psacha. The test was realized in 2008 within the PROHITECH project. Both models were built in almost the same scale (1/2.75 and 1/3, respectively). The mass and the dimens...

Comparative analysis of conventional and new seismically isolated structure

Gradjevinski materijali i konstrukcije, 2021

Extensive analytical and experimental research has been done by the authors directed to mitigation of the effects of earthquakes on structures. The research results mainly represent parts of the realized several related international projects. A selected part of the analytical studies directed to comparison between conventional and seismically isolated frame structures is presented in this paper. The responses of the applied newely developed advanced seismic isolation system HC-RMS-GOSEB to the simulated input excitation of three representative earthquakes of intensity 0.50g, have shown that it is very effective for construction of vibro-isolated and seismically resistant buildings, providing activated multistage seismic response and globally optimized seismic energy balance. Its application achieves an increase in the vibration period of the structure, far enough from the dominant period of seismic excitation. The results of the research confirm that this system is a potential solu...

State-of-Art-Review: Latest Advancements in Seismic Isolation of Structures

Civil Engineering and Architecture, 2022

Seismic isolation is effected by providing an interface between the foundations of the building and superstructure which may consist of stories above the ground level by inserting devices. Those are meant to reduce the effect of ground motions generated by an earthquake or/ and wind load. In this process, the period of the whole structure including base isolators is elongated so that ground waves containing large energy contents in the horizontal components of the earthquake may be deflected conveniently. An updated state-of-art review of isolation techniques and the design of isolated buildings is presented in this paper. The research findings in the comprehensive form are extracted out of the large volume of research papers published during the last five decades, where only some limited quality papers are selected for the preparation of this manuscript. The review generally covered papers on the analysis and design of structures with base isolation. Review is not confined to buildings with friction pendulum isolators only, but also includes the study of structural response to some other types of base isolators and dampers to seismic attacks.

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