• 한국구조물진단유지관리공학회 논문집
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• 제24권5호
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• pp.103-110
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• 2020

최신 내진설계기준 KDS 41 17 00에 비선형동적해석에 사용될 지반운동 선정 및 보정에 관한 절차가 반영되었으나 관련 문헌 부족으로 실무적 차원에서의 적용이 여전히 어려운 실정이다. 본 연구는 비선형동적해석 수행을 위한 지반운동을 선정하고 보정하기 위해 부지응답해석을 수행한 사례를 소개한다. 이에 근거하여, 현행 설계기준에 명기된 부지응답해석 관련 조항을 실무적용 차원에서 검토하였다. 그 결과 암반운동선정에 관한 설계조항이 지나치게 엄격하여 과도한 결과를 초래하는 것으로 나타났다. 이는 가속도 민감 구간을 포함한 관심주기범위를 지닌 저층 구조물일수록 더욱 부각되는 것으로 판단된다. 특히 표면지진파가 기준에 적합한 응답을 보였음에도 불구하고, 해석 전 절차의 암반운동선정과 관련된 조항으로 인해 해석 후 절차와 관계없이 지진파를 다시 선정 및 보정해야만 했다. 또한, 연약지반이거나 해당 지반에 강한 지진이 발생하는 경우에는 지반물성과 적절한 해석 기법을 올바르게 선정하기 위해 더욱 엄격한 조사가 선행되어야 한다고 판단된다. 지반물성과 해석기법에 관한 신뢰도가 조금이라도 문제가 있다면 설계용도로 사용하기에 부적합한 결과를 초래할 수 있기 때문이다.

• 한국강구조학회 논문집
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• 제9권4호통권33호
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• pp.637-647
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• 1997

제1편에서 언급한 바와 같이 기초분리 장치의 사용은 지진의 위험으로부터 구조물의 안전을 유지시키고, 지진 응답 감소에 필요한 비선형 거동은 교체가 용이한 분리장치에 국한 함으로써 구조물의 중요 부재들은 탄성 거동을 확보할 수 있다. 본 연구는 강재 Damper를 사용한 교량의 지진 응답에 대하여 연구하였다. 강재 Damper의 특성에 따른 응답을 분리 장치의 매개 변수 영향 별로 분리하여 검토 함으로써 지진시 거동을 파악하고, 적정한 분리 장치를 선정 할 수 있는 기준과 단순화된 설계 방법을 제시하였다. 제시된 시방서 형식의 설계 방법은 비선형 스펙트럼에 의한 모드 해석법으로, 관성력 또는 기초 분리 장치를 포함한 연결부 및 하부 구조의 높이별 설계력을 비교적 정확하게 평가될 수 있다. 따라서 제시된 설계 방법은 기초 분리된 교량의 기본 또는 최종 설계용으로 사용될 수 있을 것이다. 또한, 설계 방법의 타당성 검증을 위해 bilinear 이력의 강재 Damper를 사용한 P.C 교량에 대해 인공 지진파를 이용한 비선형 시간 이력 해석과 설계 응답 스펙트럼에 의한 탄성 수치 해석을 수행하여 단순 설계 방법과 비교 검토하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.544-547
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• 2003

The purpose of this paper is to develop the straightforward design guidelines of PD/PID speed controller for Industry servo drives with plug and play concept. The controller gains are uniquely determined from the current control loop dynamics, speed loop delay, and mechanical parameters. In order to eliminate the mechanical friction uncertainties, an automatic PD/PI control mode switching algorithm Is introduced using online spectrum analysis of motor torque command. The dynamic performance of the proposed scheme assures a fast tracking response curve with minimal oscillation and settling time over the whole operating conditions. For comprehensive comparison of conventional PI control scheme, extensive test is carried out on actual servo system.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 가을 학술발표회논문집
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• pp.257-264
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• 2000

Nonlinear dynamic time history analysis of a structure with energy dissipation devices is complicated and time consuming. In this regard the nonlinear static analysis is a practical alternative for evaluating the earthquake resisting capacity of a structure. In this study the nonlinear static response of a structure was obtained first, and the equivalent viscous modal damping ratio required to satisfy the performance objective was computed in the capacity spectrum format. Then proper amount of viscous dampers were installed to provide the required damping. Parametric study has been performed for the period of the structure, yield strength, and the stiffness after the first yield. According to the earthquake time history analysis results, the maximum displacement of the model structure with viscous dampers designed in accordance with the proposed method corresponds well with the target displacements that was used in the beginning of the design process.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.479-486
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• 2003

The characteristics of harmonic phase angles and phase angle differences contained in earthquake ground motions such as El Centre 1940 NS, Taft1 1952 NS, Hachinohe 1968 NS and Mexico 1985 are figured, which have been mostly overlooked in contrast with the importance placed on harmonic amplitudes. Recently, performance based design method is used for seismic design and seismic retrofitting, which needs nonlinear response analysis, there must be earthquake ground accelerations which contain the phase angle, the phase angle difference and energy input spectrum characteristics of the zone considered to be constructed building structures. To make clear the importance of phase angle differences, responses of 4 recorded earthquake ground motions, 4-earthquake ground motions normalized by 110 gal and 4 artificial earthquake motions compatible to the seismic building code of Korea are compared.

• 한국해양공학회지
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• 제19권1호
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• pp.26-32
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• 2005

Recent earthquakes, measuring over a magnitude of 5.0, on the eastern coast of Korea, have aroused interest in earthquake analyses and the seismic design of caisson-type breakwaters. Most earthquake analysis methods, such as equivalent static analysis, response spectrum analysis, nonlinear analysis, and capacity analysis, are deterministic and have been used for seismic design and performance evaluation of coastal structures. However, deterministic methods are difficult for reflecting on one of the most important characteristics of earthquakes, i.e. the uncertainty of earthquakes. This paper presents results of probabilistic seismic hazard assessment(PSHA) of an actual caisson-type breakwater, considering uncertainties of earthquake occurrences and soil properties. First, the seismic vulnerability of a structure and the seismic hazard of the site are evaluated, using earthquake sets and a seismic hazard map; then, the seismic risk of the structure is assessed.

• Structural Engineering and Mechanics
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• 제58권6호
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• pp.1045-1075
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• 2016

Shallow footings are one of the most common types of foundations used to support mid-rise buildings in high risk seismic zones. Recent findings have revealed that the dynamic interaction between the soil, foundation, and the superstructure can influence the seismic response of the building during earthquakes. Accordingly, the properties of a foundation can alter the dynamic characteristics (natural frequency and damping) of the soil-foundation-structure system. In this paper the influence that shallow foundations have on the seismic response of a mid-rise moment resisting building is investigated. For this purpose, a fifteen storey moment resisting frame sitting on shallow footings with different sizes was simulated numerically using ABAQUS software. By adopting a direct calculation method, the numerical model can perform a fully nonlinear time history dynamic analysis to realistically simulate the dynamic behaviour of soil, foundation, and structure under seismic excitations. This three-dimensional numerical model accounts for the nonlinear behaviour of the soil medium and structural elements. Infinite boundary conditions were assigned to the numerical model to simulate free field boundaries, and appropriate contact elements capable of modelling sliding and separation between the foundation and soil elements are also considered. The influence of foundation size on the natural frequency of the system and structural response spectrum was also studied. The numerical results for cases of soil-foundation-structure systems with different sized foundations and fixed base conditions (excluding soil-foundation-structure interaction) in terms of lateral deformations, inter-storey drifts, rocking, and shear force distribution of the structure were then compared. Due to natural period lengthening, there was a significant reduction in the base shears when the size of the foundation was reduced. It was concluded that the size of a shallow foundation influences the dynamic characteristics and the seismic response of the building due to interaction between the soil, foundation, and structure, and therefore design engineer should carefully consider these parameters in order to ensure a safe and cost effective seismic design.

• 감성과학
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• 제7권4호
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• pp.51-56
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• 2004

본 연구의 목적은 각각의 색채 자극 하에서의 생리신호를 측정하고자 하였다. 실험에 사용된 색채는 빨강, 노랑, 녹색, 파랑, 보라, 그리고 백색을 사용하였다. 실험은 방음 암실에서 이루어졌으며, 건강한 성인 남, 여 30명을 대상으로 하였다. 생리신호의 측정은 뇌파와 심전도를 측정하였다. 뇌파의 실험결과는 차가운 색 계통의 색채에서 $\alpha$파의 상대 전력비가 증가한 것을 볼 수 있었다. 또한 심전도의 HRV 분석 결과도 차가운 색 계통에서 HF/LF의 비가 증가한 것을 볼 수 있었으며, 이 결과로서 색채 조명이 인체의 감성변화에 영향을 미치는 것을 알 수 있었으며, 이 결과를 활용하여 색채 환경 설계에 도움을 줄 수 있으리라 사료된다.

• Earthquakes and Structures
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• 제11권4호
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• pp.539-561
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• 2016

The rate of occurrence of intraplate earthquake events has been surveyed around the globe to ascertain the average level of intraplate seismic activities on land. Elastic response spectra corresponding to various levels of averaged (uniform) seismicity for a return period of 2475 years have then been derived along with modifying factors that can be used to infer ground motion and spectral response parameters for other return period values. Estimates derived from the assumption of uniform seismicity are intended to identify the minimum level of design seismic hazard in intraplate regions. The probabilistic seismic hazard assessment presented in the paper involved the use of ground motion models that have been developed for regions of different tectonic and crustal classifications. The proposed minimum earthquake loading model is illustrated by the case study of Peninsular Malaysia which has been identified with a minimum effective peak ground acceleration (EPGA) of 0.1 g for a return period of 2475 years, or 0.07 g for a notional return period of 475 years.

• Structural Engineering and Mechanics
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• 제87권4호
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• pp.347-361
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• 2023

This research aims to assess the behavior of reinforced concrete (RC) residential buildings when moment-resisting frames (MRFs) are used as the lateral resisting system. This investigation was conducted using MIDAS Gen v.19.0. Buildings with various plan footprints (Square, Rectangular, Circular, Triangular, and Plus-Shaped), and different heights (15 m, 30 m, 45 m, and 60 m) are investigated. The defined load cases, the equivalent static lateral load pattern, and the response spectrum function were defined as stated by the American Standard (ASCE 7-16), the 1997 Uniform Building Code (UBC97), the Egyptian Code for Loads (ECP-201), and the European Standard (EC8). Extensive comparisons of the results obtained by the different codes (including the story displacement, the story drift, and the base shear) were undertaken; to assess the response of moment-resisting multi-story framed buildings under lateral loads. The results revealed that, for all study cases under consideration, both ECP-201 and EC8 gave smaller base shear, displacement, and drift by one third to one fourth, around one fourth, around one fifth, respectively for both the ELF and RSA methods if compared to ASCE 7-16 and UBC97.