Seismic Effects on Different Structural Members

Civil engineers deal with constructing differing types of structures with guaranteeing safety, sturdiness and utility. Currently days “earthquake “is a natural tragedy that affects the structures with their safety and utility. The quantity of harm that earthquake will cause to structures is rely upon sort of building, sort of soil, Technology used for earthquake resistance, and last however not the smallest amount Location of building. Effects of earthquake area unit mostly counting on sort of soil within which foundation of building is finished as a result of earthquake changes the motion of ground that results the failure foundation. Therefore it's vital to check the behavior of various soils at the time of construction of structures. Earthquake will be resisted by varied technologies utilized in building, one amongst these area unit shear wall. It improves the structural performance of building subjected to lateral forces because of earthquake excitation. Much analysis comes area unit afoot worldwide for development of effective ways for estimating unstable demands for performance-based engineering of buildings.

The experience of detailed probabilistic assessments of possible seismic effects on the territory of North Ossetia-Alania

В настоящее время во многих сейсмоактивных районах Российской Федерации (включая и территорию РСО-Алания) наблюдается определенный дефицит точных и детальных данных о возможных на этих территориях сейсмических воздействиях. Помимо того, что без этих данных не могут решаться многие академические задачи инженерной и общей сейсмологии, они также необходимы для обеспечения должного качества антисейсмического проектирования и прогнозов сейсмического риска, принятия эффективных управленческих решений и других мер защиты населения, объектов инфраструктуры и окружающей среды от возможных здесь сильных землетрясений. Поэтому настоящее исследование, направленное на уменьшение дефицита таких данных в сейсмогеологических условиях РСО-Алания представляется актуальным. Цель исследования. Совершенствованиеметодики и получение на этой основе более точных и детальных вероятностных оценок используемых в инженерно- сейсмологической практике параметров колебаний грунта при землетрясениях, представляющих опасность для территории РСО-Алания. Методы исследования. Работа выполнена с использованием оригинальной вероятностной технологии оценки сейсмической опасности, включающей в себя разработку на основе анализа большого объема экспериментальных данных по инструментальной регистрации и макросейсмическому описанию землетрясений Кавказа и других сейсмоактивных районов мира региональных моделей сильных движений грунта и сейсмичности с последующими расчетами (на основе формулы полной вероятности) результирующих характеристик возможных сейсмических воздействий на исследуемой территории. Результаты.Впервые для изучаемого района с единых методологических позиций получены уточненные вероятностные оценки широкого перечня параметров (макросейсмических интенсивностей, амплитуд, периодов, длительностей, спектров и акселерограмм) колебаний грунта при возможных на данной территории землетрясениях со средними периодами повторяемости 500, 1000, 2500 и 5000 лет, которые в ряде случаев существенно отличаются от действующих нормативов. Например, показано, что на изучаемой территории прогнозируемые амплитуды и спектры ускорений грунта в пределах одной и той же зоны балльности могут существенно (до 100%) различаться в зависимости от периодов повторяемости ожидаемых землетрясений. Вероятные спектры реакции ускорений колебаний грунта, в зависимости от частот спектральных составляющих также могут существенно (до 100%) отличаться от нормативных спектров At present, in many seismically active regions of the Russian Federation (including the territory of North Ossetia-Alania), there is a certain deficit of accurate and detailed data on possible seismic effects on these territories. In addition to the fact that without these data many academic problems of engineering and general seismology cannot be solved, they are also necessary to ensure the proper quality of earthquake-proof design and seismic risk predictions. These data is also necessary to make effective management decisions and other measures to protect the population, infrastructure and the environment from possible strong earthquakes. Therefore, the present study aimed at reducing the deficit of such data in the seismogeological conditions of North Ossetia-Alania is relevant. Aim. Improvement of the methodology and obtaining, on this basis, more accurate and detailed probabilistic estimates of the ground vibration parameters used in engineering and seismological practice during earthquakes, which are dangerous for the territory of the Republic of North Ossetia-Alania. Methods. The work was carried out using an original probabilistic technology for seismic hazard assessment, which includes the development, based on the analysis of a large amount of experimental data on instrumental registration and macroseismic description of earthquakes in the Caucasus and other seismically active regions of the world, regional models of strong ground motion and seismicity with subsequent calculations (based on the formula for complete probabilities) of the resulting characteristics of possible seismic effects on the studied territory. Results. For the first time for the studied territory, from a unified methodological standpoint, refined probabilistic estimates of a wide range of parameters (macroseismic intensities, amplitudes, periods, durations, spectra and accelerograms) of ground vibrations were obtained for possible earthquakes in a given territory with average recurrence periods of 500, 1000, 2500 and 5000 years, which in some cases differ significantly from the current standards. For example, it has been shown that in the considered territory the predicted amplitudes and spectra of ground accelerations within the same magnitude zone can differ significantly (up to 100%) depending on the recurrence periods of expected earthquakes. The probable response spectra of ground vibration accelerations, depending on the frequencies of the spectral components, can also significantly (up to 100%) differ from the standard spectra

CALCULATION FOR THE SEISMIC EFFECTS OF THE MOSQUE BUILDING NAMED AFTER AYMANI KADYROVA IN ARGUN

В статье рассматриваются расчеты на сейсмические воздействия уникального здания. С применением монолитного железобетонного перекрытия в рамном исполнении. А также из стальных конструкций в виде купола, расчеты выполняются программными комплексами «Лира» и «SCAD». The article deals with calculations for seismic effects of unique building in the shape of a globe using a monolithic reinforced concrete floor in frame execution. And also from steel structures in the form of a dome, calculations are performed using software complexes "Lira","SCAD".

Evaluation of the efficient application of «Iskra-T» electronic initiating devices in terms of crushing and seismic action of face blasts

The paper justifies the optimal delay time in non-synchronous fan blasting with the most optimal delay time between the holes being 15 ms. Experiments were conducted to assess the breaking conditions and seismic effects of face blasts in the underground conditions of the Rasvumchorrsky mine using the Iskra-T electronic initiating systems with delay times of 10, 15 and 20 ms. With the delay times of 10 and 15 ms there is no clear segregation of the blast stages and interference of compression waves, created by consecutively blasted charges, takes place, while their joint interaction leads to insignificant increase of the seismic effects on the mine workings. According to the results of ore drawing monitoring, the number of boulders with the above delay times did not exceed 10 pieces for the whole blasted volume for each round. With the delay time of 20 ms a clear segregation of the blast stages was obtained with the minimum number of 7 boulders per blast. In order to ensure acceptable rock mass fragmentation quality and reduce the seismic effect of blasting on the mine workings, as well as to preserve the pilot holes drilled, it is advisable to use reverse initiation with non-synchronized fan blasting with the delay time of 20 ms between the holes.

Seismic rocking effects on a mine tower under induced and natural earthquakes

Recent research in engineering seismology demonstrated that in addition to three translational seismic excitations along x, y and z axes, one should also consider rotational components about these axes when calculating design seismic loads for structures. The objective of this paper is to present the results of a seismic response numerical analysis of a mine tower (also called in the literature a headframe or a pit frame). These structures are used in deep mining on the ground surface to hoist output (e.g. copper ore or coal). The mine towers belong to the tall, slender structures, for which rocking excitations may be important. In the numerical example, a typical steel headframe 64 m high is analysed under two records of simultaneous rocking and horizontal seismic action of an induced mine shock and a natural earthquake. As a result, a complicated interaction of rocking seismic effects with horizontal excitations is observed. The contribution of the rocking component may sometimes reduce the overall seismic response, but in most cases, it substantially increases the seismic response of the analysed headframe. It is concluded that in the analysed case of the 64 m mining tower, the seismic response, including the rocking ground motion effects, may increase up to 31% (for natural earthquake ground motion) or even up to 135% (for mining-induced, rockburst seismic effects). This means that not only in the case of the design of very tall buildings or industrial chimneys but also for specific yet very common structures like mine towers, including the rotational seismic effects may play an important role.

Seismic hazard assessment for the underwater gas pipeline route in the water area of the Nevelskoy Strait

The presence of seismic threat multiplies the environmental hazard, especially for oil and gas production and transport facilities in water areas. Currently, there are no normative maps of general seismic zoning of the water areas of the inland and marginal seas of Russia, especially since there are practically no maps of detailed seismic zoning and seismic microzoning of even individual parts of the water areas. Taking into account the fact that intensive development of offshore oil and gas fields and the Northern Sea Route has begun, the development of such maps becomes a very urgent scientific and practical task. The seismic hazard assessment for the submerged crossing was carried out in 2008. The initial seismic effects were calculated using a probabilistic seismic hazard analysis based on five models of seismic zones and three types of models of attenuation of peak and spectral accelerations. The results of the performed calculations, including deaggregation, have shown that the initial seismicity of the area of the gas pipeline crossing route through the Nevelskoy Strait for a return period of 1,000 years is lower than indicated on the OSR-2016-B map, where the eastern end of the crossing route through the strait is characterized by the initial seismicity equal to 9 points. The soil conditions (seismic microzoning) have been taken into account by three different methods: the seismic rigidity method, the calculation method, and the method considering the thickness of Quaternary deposits. The present studies show that seismic effects vary along the pipeline route from the mainland to Sakhalin Island from 8.4 to 8.9 on the MSK-64 scale for the recurrence period of seismic shaking T = 1,000 years and from 9.3 to 9.7 points for T = 5,000 years.

Main directions of development of the theory of seismic resistance of building and structures

The article discusses the main directions of the development of the theory of seismic resistance of buildings and structures. Various models of the «building-foundation-foundation» system are presented. Much attention is paid to the influence of the foundation on seismic effects and the wave process of earthquakes.