• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.1
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• pp.65-72
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• 2009

‘Korean Highway Bridge Design Code’ provides the spectrum analysis method with response modification factors for the seismic design of typical bridges. However, considering that korean peninsula is classified as moderate seismic regions and domestic circumstances for bridge design and construction are different from other countries, the applicability of this code is not yet proved. Therefore it is required to verify that applying the spectrum analysis method fulfills the no collapse requirement which is set forth as the basic seismic design concept. In this study two typical bridges with T and ${\prod}$ type piers are selected as analysis bridges and seismic designs are carried out by applying the spectrum analysis method with design conditions given for moderate seismic regions. Based on the results obtained through deign procedures, the role of the response modification factors and fulfillment of the no collapse requirement are discussed, from which supplementary provisions for the design code are identified.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.71-74
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• 2011

최근 국제적으로 지진 발생 규모가 증대하고 있으며, 우리나라를 비롯한 많은 나라에서 구조물 및 주요 시설물에 대한 내진설계에 관심이 증대되고 있다. 지진방재는 건물자체의 안전성뿐만 아니라 내부설비 및 소장품에 대한 안전성까지 종합적으로 검토되어야 하며 이를 위한 대책이 필요한 실정이다. 본 연구의 주요목적은 예측 불가한 자연재해인 지진에 대해 일반적인 면진성능을 갖는 기초격리장치로서의 기능을 충실히 수행할 수 있는지를 확인하기 위하여 면진장치를 사용한 구조물의 면진효과를 검증하는 것이다. 또한 설계된 스프링의 탄성계수에 따른 실제 지진 시 응답의 차이를 알아보기 위하여 공진실험 및 진동대 실험을 실시하여 면진테이블 시스템의 면진성능을 평가하였다. 진동대 실험은 미국 "NEBS Requirements"에서 규정하는 요구응답스펙트럼에 상응하는 임의 지진파를 적용하였고 각각 x축과 z축 가진 후, x-y-z 축을 동시에 가진하여 수행하였다. 시험응답스펙트럼(Test Response Spectrum)은 요구응답스펙트럼(RRS)에 포락하도록 시험하여 최대가속도는 x축 방향 가진 시 90%의 감쇠효과가 나타났으며, 3축 방향 가진 시 x축 방향은 58%, y축 방향은 31%의 감쇠효과가 나타났다. 최대상대변위는 설계스트로크 140mm에 대하여 최대 85.54mm의 변위가 발생하여 안정적인 거동을 나타내었다. 본 연구에서 제안한 면진테이블 시스템은 중요 첨단장비 및 문화재 등의 전도 및 파괴를 방지하는 데 효과적일 것으로 판단된다.

• Journal of the Earthquake Engineering Society of Korea
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• v.4 no.1
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• pp.63-76
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• 2000

구조물-지반 상호작용에서 알려진 것처럼 구조물 지진응답은 구조물하부 지반조거에 따라 영향을 받는데 UBC-97을 포함한 여러내진설계규준에서 지반사태 영향을 반영하고 있다 이 연구에서는 기초크기 기초밑 지반깊이, 입력지진 작용점 및 기초 근입깊이 등의 영향을 살펴보고 깊은 지반 위에 세워진 구조물의 평균응답스펙트럼을 UBC-97 탄성응답스펙트럼과 비교하기 위해 구조물-지반 상호작용을 고려한 지진해석을 가상 3차원 유한요소법과 부구조물법을 이용하여 1952년 Taft와 1940년 El Centro 지진기록을 주파수영역에서 수행하였다 연구결과에 의하면 기초크기는 구조물 응답에 별 영향이 없고 기초저면 지반깊이는 구조물체계의 고유주기와 최대가속도를 변경시켰다 또 입력지진의 합리적 작용점은 기초저면이라는 것이 확인되었으며 깊은 지반위에 놓인 기초의 근입은 저주기영역에서 구조물 응답을 상당히 줄어들게 하였다 한편 30m 깊은 지반위에 세워진 구조물의 평균가속도와 UBC-97 가속도를 비교한 결과 UBC-97 탄성응답스펙트럼에 의한 구조물 내진설계가 안전하지 못할 수도 있으므로 UBC-97 지진계수의 할증이 필요하다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.5
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• pp.13-22
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• 2019

In order to evaluate the earthquake damage level of small and medium - sized bridges without earthquake monitoring system, we proposed an algorithm for estimating the seismic force at the target bridge location using the ground acceleration data from the earthquake observatories near the structure. In general, response spectrum analysis, which is the most widely used dynamic analysis method to design and evaluate the structural system numerically is required a response spectrum to determine the dynamic loading. In this study, selection methods of the three closest observatories from the target structure and estimation method of ground response spectrum at arbitrary locations are developed. The proposed method can consider the distance and phase between the target bridge and the seismic station and from the relationship between the acceleration amplitudes and the location of the selected seismic station, the earthquake loading of the target bridge can be determined. The proposed algorithm is estimated to be more conservative than the response spectrum evaluated by actual earthquake data.

• Journal of the KSME
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• v.20 no.5
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• pp.387-391
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• 1980

일반적으로 내진 설계라 함은 지진에 의하여 발생된 지진동이 특정한 구조물에 작용할 때 이 지 진동의 경향하에서도 구조물의 정상적인 기능을 추진할 수 있도록 설계하는 것을 말하는 바, 원자력발전소의 내진설계에 있어서도 원칙적으로는 동일한 개념이나 실시하는 규정이 타구조물에 비하여 훨씬 엄격한 것이 다른 점이라 하겠다. 현재 우리나라의 경우 원자력 발전소는 1기(고리 #1)가 가동중이고 2기(월성 #1, 고리 #2)가 거의 완공단계에 있으며 7기(고리 #3, #4, 월성 #2, 계마 #1, #2, 부구 #1, #2)가 건설작업중인 바 이중 부구의 경우만 프랑스(\ulcorner)에서 건설 예정이고 기타는 모두 미국 및 카나다에서 건설하였거나 건설 예정이므로 따라서 그 설계에 있어서도 제 규정은 대체로 미국것을 준용하고 있는 형편이다. 그러므로 본고에서 는 미국에서 시행되고 있는 방법 또는 규정에 의거하여 내진설계용 입력지진에 대하여 설명하고자 한다. 내진설계에 입력 으로 사용되는 지진을 설계기준지진(design basis earthquake, DBE)이라고 통칭하며 이 지진은 미국 규정에 의하면 응답스펙트럼(response spectrum)으로 정의되게 되어 있으며 또한 이 응답 스펙트럼에 준하는 인공정인 지진의 시간기득(artificial time history)을 작성 또는 선정하여 이를 발전소 구조물의 내진 해석 및 내진 시험 입력으로 사용하게 되어 있다.

• Journal of Korean Association for Spatial Structures
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• v.8 no.1
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• pp.57-67
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• 2008

In general, the response spectrum analysis(RSA) method is wifely used for seismic analysis of building structures, and the time history analysis(THA) is applied for computation of structural vibration caused by equipments, machines and moving loads, etc. However, compared with the RSA method, the THA method is very complex, difficult and time consuming. In this study, the maximum responses for the vertical vibration are calculated conveniently by the RSA method. At first, the process for the RSA in excitation is proposed, and the maximum modal responses are combined by CQC and SRSS methods. Also, the responses obtained by the two modal combination methods are compared to the responses by the THA. And the correlation coefficients for human activities is proposed, and the RSA responses obtained by used to the correlation coefficients are calculated. Finally, results of the proposed method are compared with those of the time history analysis and correlation coefficients should be considered for the RSA of floor structure subjected to group dynamic loads.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.4
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• pp.65-73
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• 2002

It has been recognized that the damage control must become a more explicit design consideration. In an effort to develop design methods based on performance it is clear that the evaluation of the nonlinear response is required. The methods available to the design engineer today are nonlinear time history analyses, monotonic static nonlinear analyses, or equivalent static analyses with simulated nonlinear influences. Some building codes propose the capacity spectrum method based on the nonlinear static analysis(pushover analysis) to determine the earthquake-induced demand given by the structure pushover curve. These procedures are conceptually simple but iterative and time consuming with some errors. This paper presents a nonlinear direct spectrum method(NDSM) to evaluate seismic performance of structures, without iterative computations, given by the structural initial elastic period and yield strength from the pushover analysis, especially for MDF(multi degree of freedom) systems. The purpose of this paper is to investigate the accuracy and confidence of this method from a point of view of various earthquakes and unloading stiffness degradation parameters. The conclusions of this study are as follows; 1) NDSM is considered as practical method because the peak deformations of nonlinear system of MDF by NDSM are almost equal to the results of nonlinear time history analysis(NTHA) for various ground motions. 2) When the results of NDSM are compared with those of NTHA. mean of errors is the smallest in case of post-yielding stiffness factor 0.1, static force by MAD(modal adaptive distribution) and unloading stiffness degradation factor 0.2~0.3.

• Journal of the Korean Geotechnical Society
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• v.36 no.6
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• pp.17-34
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• 2020

In response spectrum analysis of pile-supported structure, an amplified seismic wave should be used as the input ground acceleration through the site-response analysis. However, each design standard uses different input ground acceleration criteria, which leads to confusion in determining the appropriate input ground acceleration. In this study, the ground accelerations were calculated through dynamic centrifuge model test, and the response spectrum analysis was performed using the calculated ground acceleration. Then, the moments derived from the test and analysis were compared, and a method for determining the appropriate input ground acceleration in response spectrum analysis was presented. Comparison of the experimental and simulated results reveals that modeling of the ground using elastic springs allows proper simulation of the natural period of the structure, and the use of a seismic wave that is amplified at the ground surface as the input ground acceleration provided the most accurate results for the response analysis of pile-supported structures in sands.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.2
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• pp.83-93
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• 2004

In this study. the Modified Response Displacement Method(MRDM) for seismic design of underground box-type structures is proposed. Firstly, to investigate the applicability of the conventional RDM, various parametric studies are performed according to buried depth and soil conditions. Results from the conventional RDM are compared with those of time history analysis in terms of the maximum bending moment and relative displacement. The comparison shows that the velocity response spectrum and the determination method of foundation modulus which significantly influence the accuracy of RDM should be modified. Thus, the modified velocity response spectrum and the new determination method of foundation modulus are proposed under consideration of domestic conditions. In order to demonstrate the accuracy and validity of the proposed MRDM numerical analyses are performed according to different parameters such as depth of base rock, height and width of box, buried depth and soil condition. the comparison with the results of the time history analysis verifies the feasibility of the proposed MRDM for the seismic analysis.

• Journal of the Korean Geotechnical Society
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• v.37 no.12
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• pp.57-71
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• 2021

The pile-supported wharf is the port structure in which the upper deck is supported by piles or columns. By installing batter piles in this structure, horizontal load such as earthquake loads can be partially delivered as axial forces. The codes suggests using the response spectrum analysis as a preliminary design method for seismic design of pile-supported wharf, and suggests modeling the piles using virtual fixed points or soil spring methods for this analysis. Recently, several studies have been conducted on pile-supported wharves composed of vertical piles to derive a modeling method that appropriately simulates the dynamic response of structures during response spectrum analysis. However, studies related to the response spectrum analysis of pile-supported wharves with batter piles are insufficient so far. Therefore, this study performed the dynamic centrifuge model test and response spectrum analysis to evaluate the seismic performance according to the modeling method of pile-supported wharves with batter piles. As a result of test and analysis, it is confirmed that modeling using the Terzaghi (1955) constant of horizontal subgrade reaction (n_h) most appropriately simulates the actual response in the case of the pile-supported wharf with batter piles.