• Earthquakes and Structures
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• 제8권6호
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• pp.1363-1386
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• 2015

The October 23 2011 Van Earthquake is studied from an earthquake engineering point of view. Strong ground motion processing was performed to investigate features of the earthquake source, forward directivity effects during the rupture process as well as local site effects. Strong motion characteristics were investigated in terms of peak ground motion and spectral acceleration values. Directiviy effects were discussed in detail via elastic response spectra and wide band spectograms to see the high frequency energy distributions. Source parameters and slip distribution results of the earthquake which had been proposed by different researchers were summarized. Influence of the source parameters on structural response were shown by comparing elastic response spectra of Muradiye synthetic records which were performed by broadband strong motion simulations of the earthquake. It has been emphasized that characteristics of the earthquake rupture dynamics and their effects on structural design might be investigated from a multidisciplinary point of view. Seismotectonic calculations (e.g., slip pattern, rupture velocity) may be extended relating different engineering parameters (e.g., interstorey drifts, spectral accelerations) across different disciplines while using code based seismic design approaches. Current state of the art building codes still far from fully reflecting earthquake source related parameters into design rules. Some of those deficiencies and recent efforts to overcome these problems were also mentioned. Next generation ground motion prediction equations (GMPEs) may be incorporated with certain site categories for site effects. Likewise in the 2011 Van Earthquake, Reverse/Oblique earthquakes indicate that GMPEs need to be feasible to a wider range of magnitudes and distances in engineering practice. Due to the reverse faulting with large slip and dip angles, vertical displacements along with directivity and fault normal effects might significantly affect the engineering structures. Main reason of excessive damage in the town of Erciş can be attributed to these factors. Such effects should be considered in advance through the establishment of vertical design spectra and effects might be incorporated in the available GMPEs.

• Earthquakes and Structures
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• 제3권2호
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• pp.141-168
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• 2012

The Retrofit Yield Spectrum (RYS) is a new spectrum-based device that relates seismic demand of a retrofitted structure with the fundamental design parameters of the retrofit. This is obtained from superposition of Yield Point Spectra with design charts that summarize in pertinent spectrum-compatible coordinates the attributes of a number of alternative retrofit scenarios. Therefore, once the requirements for upgrading a given structure have been determined, the RYS enable direct insight of the sensitivity of the seismic response of the upgraded structure to the preliminary design decisions made while establishing the retrofit plan. By virtue of their spectrum-based origin, RYS are derived with reference to a single mode of structural vibration; a primary objective is to control the contribution of this mode in the retrofit design so as to produce a desirable distribution of damage at the ultimate limit state by removing soft storey formations and engaging the maximum number of structural members in deformation, in response to the input motion. Calculations are performed with reference to the yield-point, where secant stiffness is proportional to the flexural strength of reinforced concrete members. Derivation and use of the Retrofit Yield Spectra (RYS) refers to the seismic demand expressed either in terms of spectral acceleration, spectral displacement or interstory drift, at yield of the first storey. A reinforced concrete building that has been tested in full scale to a sequence of simulated earthquake excitations is used in the paper as a demonstration case study to examine the effectiveness of the proposed methodology.

• 한국지진공학회논문집
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• 제20권6호
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• pp.413-424
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• 2016

The vertical design spectrum for Korea, which is known to belong to an intra-plate region, is developed from the ground motion records of the earthquakes occurred in Korea and overseas intra-plate regions. From the statistical analysis of the vertical response spectra, a mean plus one standard deviation spectrum in lognormal distribution is obtained. Regression analysis is performed on this curve to determine the shape of spectrum including transition periods. The developed design spectrum is valid for the estimation both spectral acceleration and displacement. The ratio of vertical to horizontal response spectrum for each record is calculated. Statistical analysis of the ratios rendered the vertical to horizontal ratio (V/H ratio). Subsequently the ratio between the peak vertical ground acceleration to the horizontal one is obtained.

• Structural Engineering and Mechanics
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• 제41권6호
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• pp.759-773
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• 2012

The objective of this paper is to present an energy-based method for calculating target displacement of RC structures. The method, which uses the Newmark-Hall pseudo-velocity spectrum, is called the "Pseudo-velocity Spectrum (PSVS) Method". The method is based on the energy balance concept that uses the equality of energy demand and energy capacity of the structure. First, nonlinear static analyses are performed for five, eight and ten-story RC frame structures and pushover curves are obtained. Then the pushover curves are converted to energy capacity diagrams. Seven strong ground motions that were recorded at different soil sites in Turkey are used to obtain the pseudo-acceleration and the pseudo-velocity response spectra. Later, the response spectra are idealised with the Newmark-Hall approximation. Afterwards, energy demands for the RC structures are calculated using the idealised pseudo-velocity spectrum. The displacements, obtained from the energy capacity diagrams that fit to the energy demand values of the RC structures, are accepted as the energy-based performance point of the structures. Consequently, the target displacement values determined from the PSVS Method are checked using the displacement-based successive approach in the Turkish Seismic Design Code. The results show that the target displacements of RC frame structures obtained from the PSVS Method are very close to the values calculated by the approach given in the Turkish Seismic Design Code.

• 한국전산구조공학회논문집
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• 제33권3호
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• pp.159-169
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• 2020

변전소 구조물 내부에 설치되는 전력설비의 내진설계 시 사용되는 변수인 가속도 증폭계수는 미국, 일본과 국내의 변전소 내진설계기준에서 제시되어 있다. 국내 설계기준에 제시된 가속도 증폭계수는 미국, 일본의 설계기준에서 제시된 계수와는 달리 변전소 구조물의 층수가 4층 이상일 경우에는 동적해석을 수행하여 가속도 증폭계수를 구하게 되어 있다. 국내의 변전소 구조물은 대부분 층수가 4~5층이므로 기존의 가속도 증폭계수는 실제 변전소 구조물에 적용하기에 미흡한 상황이다. 국내 변전소 구조물 형식에 적합한 가속도 증폭계수를 제시하기 위하여 대표적인 7가지 구조형식의 변전소 구조물에 대하여 가속도 증폭계수를 평가하였다. 가속도증폭계수는 변전소 구조물에 대하여 원거리 지진과 근거리 지진을 사용하여 내부-구조물 응답스펙트럼을 작성하여 이로부터 평가하였다. 미국, 일본 전력설비 내진설계 기준에 따른 각각의 가속도 증폭계수 α_J, α_A는 근거리 및 원거리 지진을 사용한 동적 해석으로 구한 가속도 증폭계수에 비하여 다소 과대평가하는 경향이 있다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2005년도 공동학술대회 논문집
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• pp.87-92
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• 2005

강진이 발생시 국내 지진동 수준 및 감쇠특성을 간접적으로 유추하기 위하여 2005년 3월 20일 발생한 규모 7.0의 후쿠오카 지진의 감쇠특성을 산정하고 그 결과의 적합성 여부를 알아보았다. 일본 방재과학 기술연구소에 운영중인 시추공 지진관측소 KIK-net 기록의 지반운동(PGA, SA)과 기존에 전력연구원에서 개발한 고리원전 부지에 대한 지반운동 감쇠식의 지반운동(PGA, SA)을 비교해 본 결과 잘 부합되었으며, 이로부터 고리원전 감쇠식이 강진에 대한 지진동을 비교적 적합하게 평가함을 확인할 수 있었다. 또한 시추공 KIK-net 자료의 응답스펙트럼과 일본의 원전 설계스펙트럼인 오사키 스펙트럼을 비교한 결과 후쿠오카 지진의 진동 수준이 낮게 평가되었다. 이는 전 세계에서 발생하는 강진 자료를 이용한 경험적인 응답스펙트럼이라고 할지라도 부지특성에 따라 부합되지 않을 수도 있음을 시사하고 있어 부지고유 응답스펙트럼의 개발이 필요함을 재차 확인하였다.

• 지구물리
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• 제8권3호
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• pp.109-113
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• 2005

강진이 발생시 국내 지진동 수준 및 감쇠특성을 간접적으로 유추하기 위하여 2005년 3월 20일 발생한 규모 7.0의 후쿠오카 지진의 감쇠특성을 산정하고 그 결과의 적합성 여부를 알아보았다. 일본 방재과학 기술연구소에 운영중인 시추공 지진관측소 KIK-net 기록의 지반운동(PGA, SA)과 기존에 전력연구원에서 개발한 고리원전 부지에 대한 지반운동 감쇠식의 지반운동(PGA, SA)을 비교해 본 결과 잘 부합되었으며, 이로부터 고리원전 감쇠식이 강진에 대한 지진동을 비교적 적합하게 평가함을 확인할 수 있었다. 또한 시추공 KIK-net 자료의 응답스펙트럼과 일본의 원전 설계스펙트럼인 오사키 스펙트럼을 비교한 결과 후쿠오카 지진의 진동 수준이 낮게 평가되었다. 이는 전 세계에서 발생하는 강진 자료를 이용한 경험적인 응답스펙트럼이라고 할지라도 부지특성에 따라 부합되지 않을 수도 있음을 시사하고 있어 부지고유 응답스펙트럼의 개발이 필요함을 재차 확인하였다.

• Structural Engineering and Mechanics
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• 제53권5호
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• pp.897-919
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• 2015

In this study, the effects of ground shocks due to explosive loads on the dynamic response of historical masonry bridges are investigated by using the multi-point shock response spectrum method. With this purpose, different charge weights and distances from the charge center are considered for the analyses of a masonry bridge and depending on these parameters frequency-varying shock spectra are determined and applied to each support of the two-span masonry bridge. The net blast induced ground motion consists of air-induced and direct-induced ground motions. Acceleration time histories of blast induced ground motions are obtained depending on a deterministic shape function and a stationary process. Shock response spectrums determined from the ground shock time histories are simulated using BlastGM software. The results obtained from uniform and multi-point response spectrum analyses cases show that significant differences take place between the uniform and multi-point blast-induced ground motions.

• Wind and Structures
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• 제4권1호
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• pp.63-72
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• 2001

This paper presents results of a study on wind loads and wind induced dynamic response of bridge jointed twin-towered buildings. Utilizing the high-frequency force balance technique, the drag and moment coefficients measured in wind tunnel tests, and the maximum acceleration rms values on the top floor of towers, are analyzed to examine the influence of building's plan shapes and of intervals between towers. The alongwind, acrosswind and torsional modal force spectra are investigated for generic bridge jointed twin-towered building models which cover twin squares, twin rhombuses, twin triangles, twin triangles with sharp corners cut off, twin rectangles and individual rectangle with the same outline aspect ratio as the twin rectangles. The analysis of the statistical correlation among three components of the aerodynamic force corroborated that the correlation between acrosswind and torsional forces is significant for bridge jointed twin-towered buildings.

• 한국지진공학회논문집
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• 제3권1호
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• pp.21-28
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• 1999

본 연구의 목적은 한반도 남부 지역에서의 지진동 감쇄식을 개발하는 것이다 활용가능한 계기 지진 자료로부터 지진원 및 지반 매질의 특성을 추정하고 그 값을 입력 요소로써 사용하였다 확률진동이론에 의하여 최대 지반가속도 및 의사 속도 응답스펙트럼을 모사하여 이로부터 최대지반 가속도 및 의사 속도 응답스펙트럼에 대한 감쇄식을 지역규모 및 진원거리의 함수로 개발하였다