№4 2019
№4 2019

№4 2019

№4 2019

Content

Taking into Account the Dynamic Properties of the Soil when Calculating the Pile Foundations of Nuclear Facilities under Seismic Effcts

Authors:    Travin Sergei M.   
Rubric:     Theoretical and experimental studies   

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Pile foundations are among the most reliable and proven types of foundations. They used in nuclear power engineering for a variety of impacts, including seismic. At the same time, one of the most diffilt issues is the evaluation of the strength of piles during an earthquake, taking into account the dynamic properties of the base. Currently, there are various approaches to this assessment, the results of which can signifiantly affct the objective condition of the bearing capacity of the piles. In this regard, it is necessary to consider the degree of inflence of various ways of taking into account the dynamic properties of the base on the results of calculating the strength of piles during an earthquake. The study of these issues is devoted to this article.


“Dangerous Directions of Seismic Excitation” and Combination of the Close Modal Responses in Linear Spectral Analysis

Authors:    Tyapin A.G.   
Rubric:     Theoretical and experimental studies   

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This paper continues the discussion on the linear spectral analysis using “dangerous directions of seismic excitation” concept. It is shown that in case all components of seismic excitation have similar response spectra, this “directional” approach, though non-physical, gives similar results to the conventional more physical approach, accounting for the statistical independence of diffrent components. This statement, previously proved for the modal responses with separated frequencies, here is extended for the case of close modal frequencies. If the excitation is diffrent, the “directional” approach leads to the systematic errors. The author once again considers the inertial load vectors in the nodes and studies which of them rotate along with the rotation of the “seismic excitation direction” set up by the analyst, and which of them keep their direction and change only module. Besides, the author notes certain limitation of the implementation of the D’Alambert principle to the quasi-static analysis of the damped systems. It turns out, that this approach, treating inertial loads as quasi-static and neglecting damping in the left-hand parts of the equation, gives reasonable results only for the internal forces, but not displacements, and only for systems either with homogeneous damping, or statically-determined.


Seismic Monitoring of Technogenic Impact on the Territory of Western Siberia

Authors:    Emanov Alexandr F.    Emanov Alexey A.   
Rubric:     Seismic zoning   

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The use of a network of seismological stations allowed us to estimate the level of anthropogenic seismic impact on buildings and structures in Western Siberia. Considered induced seismicity at mining sites. It is shown that the number of manmade earthquakes is growing, and the largest energy has reached a destructive level. An assessment of the level of impact on the region of industrial explosions is given, methods for monitoring the seismic effect of industrial explosions are developed, and measures are proposed to ensure the reduction of the seismic effect of industrial explosions. It is shown that for low-seismic areas it is necessary to carry out the refinement of seismic hazard due to man-made factors.


Seismic Isolation Protection System for the 1081-bed Eskişehir City Hospital in Turkey

Authors:    Huber Peter    Mark Bresler   
Rubric:     Seismic safety and seismic isolation of buildings   

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The Eskişehir City Hospital with four building blocks is located east of Istanbul in a highly seismic zone with up to 0,6g PGA. To avoid any damages to the structure or fatalities and enable absolute continued functionality even after the maximum credible earthquake (MCE) event, it was decided to apply seismic isolation with pendulum isolators. This paper will show the design considerations to limit the base shear within the isolated building blocks for the MCE event down to less than 0,13 W (= seismic weight = DL + 0,3LL) on isolator top level and max. 0,2 W on the upper floor building levels and the realization with suitable seismic pendulum isolators. For these low shear level requirements the isolator performance was adjusted to 3,5s effective period and 26% damping. With the strict quality supervision during the production procedure, with third party prototype testing at EU Center in Pavia and with third party production testing at University Munich, the reliability and durability of the isolators to resist up to five or more MCE events without damages was proven. The approach for this project is unique in a way that absolute no damages to the structure, to the content and the seismic isolators have been acceptable for the MCE event .


Certifiation System of Seismic Isolation Devices in Japan

Authors:    Feng Demin    Liu Wenguang    Miyama Takafumi   
Rubric:     Seismic safety and seismic isolation of buildings   

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In In Japan, the building law has revised to include the seismic isolation technology into the building code in 2000. Notifiation (Kokuji) 2009 and 1446 stand for seismic design code and certifiation system of seismic isolation devices, respectively. All seismic isolation devices must be certifid by Ministry of Land, Infrastructure, Transport and Tourism (MLIT) before using. In 2015, the factory production control (FPC) certifiation system to include inspection at factory was strengthened due to one company’s falsifying FPC test data. Since there is no independent testing laboratory in Japan, all the type and FPC tests are usually conducted by the manufacturer themselves. In 2017, changes of characteristics of seismic isolation devices due to the long-period and longduration ground motions have to be considered in the design in the determined long period areas. It is stipulated in the other code. The certification authorities known as notifid inspection bodies are even opened to private companies now. The devices have been roughly classifid into three kinds: isolators, dampers and restoring bearings. The Japan Society of Seismic Isolation (JSSI) has published a 750 pages catalog in 2009 to include all manufacturers for reference. The information about the certifiation authorities and certified devices can be checked easily vie web pages. This paper will focus on the performance properties of seismic isolation devices required for certifiation. Both type testing and FPC tests will be introduced. The details of lead rubber bearings and viscous fluid dampers are compared with EN15129 for better understanding. The contents of LRB include following categories: Materials, Dimensions, Horizontal capacities, Vertical properties, Horizontal properties, Dependency properties and Creep. The contents of viscous dampers include Materials, Dimensions, Horizontal properties and Dependency properties.


Recent Developments in New Zealand in Seismic Isolation, Energy Dissipation and Vibration Control of Structures (2019)

Authors:    Whittaker David   
Rubric:     Seismic safety and seismic isolation of buildings   

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Recent activity in the implementation of seismic isolation, energy dissipation and vibration control of structures in New Zealand is summarised. Recent severely damaging earthquakes in New Zealand have left many buildings and infrastructure systems inoperable and not repairable, leading to their demolition. Owners and engineers are now seeking systems that will provide more resilient seismic behaviour. Resilient structures will be able to recover operation and function quickly after a major earthquake compared with conventional structural systems. Earthquake protection technologies now being developed and used to make more seismically resilient structures include seismic isolation and energy dissipation systems. These systems can provide better damage control and repairability of structures.The paper summarises recent projects in New Zealand that have incorporated seismic isolation and energy dissipation and other earthquake protection systems such as dissipative brace systems. A draft New Zealand Guideline for the design of seismic isolation systems for buildings was recently published. The Guideline makes recommendations for how engineers should design isolated buildings to meet performance requirements that will often be well in excess of the minimum requirements of the national building code. Details of the design Guideline are summarised and examples of the design displacement and acceleration demands in various main centres of New Zealand are also given.


Experimental Model for Double Concave Sliding Bearings

Authors:    Adzhemyan A.    Benzoni Gianmario    Lomiento Giuseppe   
Rubric:     Seismic safety and seismic isolation of buildings   

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This study deals with the modeling of sliding friction seismic isolation devices. Recent large-scale experimental tests confimed the need for accurate models to account for the friction performance in the ranges of loads, velocity and displacement expected during a seismic excitation. An existing experimental model previously validated for single concave isolators is here extended to double concave sliding isolators. Full-scale mono-directional tests on a set of double concave friction bearings in are used to validate and calibrate the model. The friction model includes three independent functions to account for the effcts of applied vertical load, velocity, and cycling effcts associated to heating. The applicability of the model to the double concave isolators is discussed, in comparison with earlier results of single concave isolators.




Rubric:     Conferences. Symposia. Meetings   

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XIII Russian National Conference on Earthquake Engineering and Seismic Zoning (with International Participation) 16th World Conference on Seismic Isolation, Energy Dissipation and Regulation of Dynamic Characteristics of Structures

Authors:    Bubis A.A.    Smirnova L.N.   
Rubric:     Conferences. Symposia. Meetings   

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