• Earthquakes and Structures
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• 제8권1호
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• pp.133-152
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• 2015

This paper investigates the soil effect on seismic behaviour of reinforced concrete (RC) buildings by using the spread plastic hinge model which includes material and geometric nonlinearity of the structural members. Therefore, typical reinforced concrete frame buildings are selected and nonlinear dynamic time history analyses and pushover analyses are performed. Three earthquake acceleration records are selected for nonlinear dynamic time history analyses. These records are adjusted to be compatible with the design spectrum defined in Turkish Seismic Code. Interstory drifts and damages of selected buildings are compared according to local soil classes. Also, capacity curves of these buildings are compared with maximum responses obtained from nonlinear dynamic time history analyses. The results show that, soil class influences the seismic behaviour of reinforced concrete buildings, significantly.

• Structural Engineering and Mechanics
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• 제51권3호
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• pp.447-470
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• 2014

Numerical simulation of the non-linear behavior of (RC) structural walls subjected to severe earthquake ground motions requires a reliable modeling approach that includes important material characteristics and behavioral response features. The objective of this paper is to optimize a simplified method for the assessment of the seismic response and damage development analyses of an RC structural wall building using macro-element model. The first stage of this study investigates effectiveness and ability of the macro-element model in predicting the flexural nonlinear response of the specimen based on previous experimental test results conducted in UCLA. The sensitivity of the predicted wall responses to changes in model parameters is also assessed. The macro-element model is next used to examine the dynamic behavior of the structural wall building-all the way from elastic behavior to global instability, by applying an approximate Incremental Dynamic Analysis (IDA), based on Uncoupled Modal Response History Analysis (UMRHA), setting up nonlinear single degree of freedom systems. Finally, the identification of the global stiffness decrease as a function of a damage variable is carried out by means of this simplified methodology. Responses are compared at various locations on the structural wall by conducting static and dynamic pushover analyses for accurate estimation of seismic performance of the structure using macro-element model. Results obtained with the numerical model for rectangular wall cross sections compare favorably with experimental responses for flexural capacity, stiffness, and deformability. Overall, the model is qualified for safety assessment and design of earthquake resistant structures with structural walls.

• 한국강구조학회 논문집
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• 제23권1호
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• pp.1-12
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• 2011

강구조 접합부 설계에 '전강도 접합' 개념이 도입됨에 따라 비선형 정적 해석의 결과를 이용한 설계가 주목을 받고 있다. 그러나 현재 실무에 적용하기에는 생소한 개념이어서 어려움이 있다. 또한 대부분의 기존 연구가 가상의 고층 구조물에 대한 내용 이어서 실제 대다수 설계가 이루어지는 중 저층 산업용 구조물에 대한 연구는 부족하다. 이에 본 연구에서는 실제 진행 중인 중 저층 산업용 구조물의 비선형 정적 해석을 위한 간단 명료한 하중 패턴을 3차원 해석 모델에 대해 제시하여 해석을 수행하였고, 실무에서의 유용성을 위해 2차원 해석 모델에 대한 보다 간단한 하중 패턴을 제시하였다. 또한 해석 결과를 이용하여 접합부를 설계하는 과정에서 나타날 수 있는 문제점에 대해 비선형 정적 해석에 사용하는 힌지 특성을 간단한 유추를 통해 새롭게 제시하였다. 제시된 하중 패턴은 서로 다른 방법으로 구하였으나 동일한 결과를 보여 상호 신뢰성을 입증하였으며, 제시된 힌지 특성을 적용한 구조물의 해석 결과로부터 합리적인 결과를 얻어 그 타당성을 검증하였다.

• Earthquakes and Structures
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• 제5권6호
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• pp.625-655
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• 2013

This paper investigated the seismic behaviour of an innovated non-ductile precast concrete wall structural system; namely HC Precast System (HCPS). The system comprises load-bearing precast wall panels merely connected only to column at both ends. Such study is needed because there is limited research information available in design codes for such structure particularly in regions having low to moderate seismicity threats. Experimentally calibrated numerical model of the wall system was used to carry out nonlinear pushover analyses with various types of lateral loading patterns. Effects of laterally applied single point load (SPL), uniformly distributed load (UDL), modal distributed load (MDL) and triangular distributed load (TDL) onto global behaviour of HCPS were identified. Discussion was focused on structural performance such as ductility, deformability, and effective stiffness of the wall system. Thus, a new method for engineers to estimate the nonlinear deformation of HCPS through linear analysis was proposed.

• 한국강구조학회 논문집
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• 제22권4호
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• pp.325-334
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• 2010

본 연구에서는 반강접 접합부 배치에 따른 구조물 거동특성을 파악하기 위하여 KBC2005 건축구조설계기준으로 비가새 5층 철골 구조물을 설계하여 모든 접합부를 완전 강접합부과 반강접 접합부로 이상화한 경우 그리고 반강접 접합부를 수직배치 및 수평배치한 경우에 대하여 푸쉬오버 구조해석을 실시하였다. 철골 보 및 기둥의 모멘트-곡률관계는 화이버모델을 이용하여 확인하였으며 반강접 접합부의 모멘트-회전각 관계는 3-매개변수 파워모델을 이용하여 나타내었다. KBC2005 등가정적횡하중을 받는 2차원 구조물에 대한 푸쉬오버 구조해석을 실시하여 지붕충변위, 밑면전단력, 접합부 요구연성도, 소성힌지 발생순서 그리고 초과강도계수, 연성계수, 반응수정계수와 같은 설계계수 등을 확인하였다. 반강접 접합부를 부분적으로 사용하면 모든 접합부에 반강접 접합부를 사용한 골조 보다 큰 강도 및 강성도를 확보 할 수 있었고 모든 접합부에 강접 접합부를 사용한 골조 보다 큰 연성능력을 확보할 수 있었다. 초과강도계수는 기준과 비슷하였지만 반응수정계수는 기준 보다 훨씬 큰 값을 보였다. TSD 접합부는 예제 구조물에서 경제성과 안전성을 확보할 수 있음을 확인할 수 있었다.

• Structural Engineering and Mechanics
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• 제89권5호
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• pp.491-505
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• 2024

This study evaluates the seismic performance of a premodern six story reinforced concrete building typology designed during the communism period of Albania and build throughout the country. During the November 26, 2019 Earthquake in Albania, the most affected reinforced concrete buildings were among the old templates, lacking shear walls and inadequate reinforcement details which suffer from concrete aging. The mathematical model of the selected building is done in the environments of ZeusNL software, developed especially for earthquake engineering applications. The capacity curve of the structure is gained using the conventional static nonlinear analysis. On the other hand, the demand estimation is utilized using one of the recent methods known as Incremental Dynamic Analysis with a set of 18 ground motion records. The limit states in both curves are defined based on the modern guidelines. For the pushover, immediate occupancy (IO), life safety (LS) and collapse prevention (CP) are plotted in the same graph with capacity curve. Furthermore, on each IDA derived, the IO, CP and global instability (GI) are determined. Moreover, the IDA fractiles are generated as suggested by the literature, 16%, 50% (median) and 84%. In addition, the comparative assessment of the IDA median with capacity curve shows good correlation points. Lastly, this study shows the approach of determination of LS in IDA fractiles for further vulnerability assessment based on the local seismic hazard map with 95 and 475 return period.

• 한국산학기술학회논문지
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• 제12권9호
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• pp.4216-4222
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• 2011

본 연구는 조적 끼움벽을 고려하지 않은 기존 학교건물의 비탄성 거동과 조적 끼움벽을 고려한 기존 학교 건물의 거동특성을 비교 검토하였다. 해석 결과와 실험 결과를 비교했을 때 하중-변위 곡선과 소성힌지 분포상태에서 유사함을 확인할 수 있었다. 따라서 조적 끼움벽을 고려한 비선형 정적해석의 유효성을 검증하였다. 골조내부가 전부 조적벽으로 채워진 경우 조적벽체의 영향에 의하여 초기 강성과 강도가 증가하고 항복 전까지는 근사한 거동을 보여주며 항복이후에는 변형이 커질수록 오차가 증가하며, 골조높이의 2/3 높이가 조적벽으로 채워진 경우 초기 강성과 항복강도가 단순골조에 비하여 약간 크게 나타나고 있으며, 조적벽체의 균열이 발생한 이후에는 급격히 강도가 저하되고 있다. 골조높이의 1/3 높이가 조적벽으로 채워진 경우 초기 강성과 항복강도가 단순골조와 비슷하며 항복점은 오히려 단순 골조의 항복점보다 저하되나, 최대강도는 단순 골조와 유사하다. Pushover 해석에 의한 하중-변위 관계곡선과 실제 실험에 의한 하중-변위 관계곡선을 비교해 보면 항복 전까지는 근사한 거동을 보여주며 항복이후에는 변형이 커질수록 오차가 증가하나 실제 구조물에서는 변형의 한계가 존재하므로 해석모델로서 유용하게 사용할 수 있다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 추계 학술발표회논문집
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• pp.205-212
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• 2003

To evaluate the seismic performance of multistory building structures use an equivalent SDOF model. This paper presents a method of converting a MDOF system into an equivalent SDOF model. The principal objective of this investigation is to evaluate appropriateness of converting method through perform nonlinear time history analysis of a multistory building structures and an equivalent SDOF model. The hysteresis rules to be used an equivalent SDOF model is obtained from the pushover analysis. The conclusion of this study is following; A method of converting a MDOF system into an equivalent SDOF model through the nonlinear time history response analysis is valid. The representative lateral displacement of a moment resisting reinforced concrete frames is close to the height of the first modal participation vector $_1$$\beta$｛$_1$u｝=1. It can be found that the hysteresis rule of an equivalent SDOF model have influence on the time history response. Therefore, it is necessary for selecting hysteresis rules to consider hysteresis characteristics of a moment resisting reinforced concrete frames.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 추계 학술발표회논문집
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• pp.231-238
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• 2003

The overstrength factor and the ductility factor are the two important factors that determines response modification factors used in current seismic codes. The objective of this paper is to obtain the overstrength and ductility factors of special concentric braced frames. For this purpose pushover analysis is performed with model structures until the maximum inter-story drift reaches 2.5% of story height. According to the analysis results, the overstrength factors increase as the height of structures decreases and the span length increases. Ductility factors for mid-story structures turns out to be higher than the other structures and span length does not contribute much to ductility factors.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.180-187
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• 1998

In this paper the attention is focused on the modeling of reinforced concrete(R/C) wall structures to check effectiveness and reliability of elasto-plastic analysis. A relatively simple and reliable wall model is investigated, which is suitable to be efficiently incorporated in a practical pushover analysis of R/C wall structural systems. Two types of analogous frames have been examined to the stress analysis of shear walls. One analogous frame is similar to the widely used wide-column model, the second analogous frame also is called truss model which includes vertical edge column and braces. Further studies are needed to apply to nonlinear seismic analysis of building structure with R/C shear walls.