• Title/Summary/Keyword: Seismic code

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Assessment of Code-specified Ground Motion Selection Criteria with Accurate Selection and Scaling Methods - II Seismic Response (구조물 동적해석을 위한 현행 내진설계기준의 입력 지반 운동 선정 조건 타당성 평가 - II 지진응답)

  • Ha, Seong Jin;Han, Sang Whan;Oh, Jang Hyun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.21 no.4
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    • pp.181-188
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    • 2017
  • Current seismic design provisions such as ASCE 7-10 provide criteria for selecting ground motions for conducting response history analysis. This study is the sequel of a companion paper (I - Ground Motion Selection) for assessment of the ASCE 7-10 criteria. To assess of the ASCE 7-10 criteria, nonlinear response history analyses of twelve single degree of freedom (SDF) systems and one multi-degree of freedom (MDF) system are conducted in this study. The results show that the target seismic demands for SDF can be predicted using the mean seismic demands over seven and ten ground motions selected according to the proposed method within an error of 30% and 20%, respectively

The need for upgrading the seismic performance objectives

  • Kutanis, Mustafa;Boru, Elif Orak
    • Earthquakes and Structures
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    • v.7 no.4
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    • pp.401-414
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    • 2014
  • The economic consequences of large earthquakes require a revolutionary change in the seismic performance objective of residential and commercial buildings. The majority of total construction costs consist of non-structural and architectural costs. Therefore, the aim of this research is to upgrade current Life Safety performance objectives and to offset adverse effects on country's economy after an occurrence of large earthquakes. However, such a proposal cannot easily prove the feasibility of cost-benefit analysis in structural design. In this paper, six generic reinforced concrete frames and dual system structures designed based on Turkish Seismic Code were used in cost analysis. The study reveals that load bearing structural systems with Immediate Occupancy performance level in seismic zones can be achieved with negligible costs.

Seismic Response Analysis Considering the Site Effect in Two Dimensional Cases (부지효과를 고려한 2차원 평면상의 지진응답해석)

  • 김민규;임윤묵;김문겸
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2001.09a
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    • pp.83-90
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    • 2001
  • The site effects of local geological conditions on seismic ground motion are performed using 2D numerical method. For the analysis, a numerical method far ground response analysis using FE-BE coupling method is developed. The total system is divided into two parts so called far field and near field. The far field is modeled by boundary element formulation using the multi-layered dynamic fundamental solution that satisfied radiational condition of wave. And this is coupled with near field modeled by finite elements. In order to verify the seismic response analysis, the results are compared with those of commercial code. As a result, it is shown that the developed method can be an efficient numerical method to solve the seismic response analysis of the site effect in 2D problem.

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Fluid Effects on the Core Seismic Behavior of a Liquid Metal Reactor

  • Koo, Gyeong-Hoi;Lee, Jae-Han
    • Journal of Mechanical Science and Technology
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    • v.18 no.12
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    • pp.2125-2136
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    • 2004
  • In this paper, a numerical application algorithm for applying the CFAM (Consistent Fluid Added Mass) matrix for a core seismic analysis is developed and applied to the 7-ducts core system to investigate the fluid effects on the dynamic characteristics and the seismic time history responses. To this end, three cases such as the in-air condition, the in-water condition without the fluid coupling terms, and the in-water condition with the fluid coupling terms are considered in this paper. From modal analysis, the core duct assemblies revealed strongly coupled out-of-phase vibration modes unlike the other cases with the fluid coupling terms considered. From the results of the seismic time history analysis, it was also verified that the fluid coupling terms in the CFAM matrix can significantly affect the impact responses and the seismic displacement responses of the ducts.

Sensitivity analysis of probabilistic seismic behaviour of wood frame buildings

  • Gu, Jianzhong
    • Earthquakes and Structures
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    • v.11 no.1
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    • pp.109-127
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    • 2016
  • This paper examines the contribution of three sources of uncertainties to probabilistic seismic behaviour of wood frame buildings, including ground motions, intensity and seismic mass. This sensitivity analysis is performed using three methods, including the traditional method based on the conditional distributions of ground motions at given intensity measures, a method using the summation of conditional distributions at given ground motion records, and the Monte Carlo simulation. FEMA P-695 ground motions and its scaling methods are used in the analysis. Two archetype buildings are used in the sensitivity analysis, including a two-storey building and a four-storey building. The results of these analyses indicate that using data-fitting techniques to obtain probability distributions may cause some errors. Linear interpolation combined with data-fitting technique may be employed to improve the accuracy of the calculated exceeding probability. The procedures can be used to quantify the risk of wood frame buildings in seismic events and to calibrate seismic design provisions towards design code improvement.

Impact of shear wall design on performance and cost of RC buildings in moderate seismic regions

  • Mahmoud, Sayed;Salman, Alaa
    • Earthquakes and Structures
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    • v.21 no.5
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    • pp.489-503
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    • 2021
  • This research aims to investigate the seismic response of RC shear wall buildings of 5-, 6-, 7-, 8-, 9-, and 10-story designed as conventional and ductile and located in moderate seismic zone in Saudi Arabia in accordance with the seismic provisions of the American code ASCE-7-16. Dynamic analysis is conducted using the developed models in ETABS and the design spectra of the selected zone. The seismic responses of a number of design variations are evaluated in terms of story displacements, drift, shear and moments of both conventional and ductile building models as performance measures and presented comparatively. In addition, pushover analysis is also performed for the lowest and highest building models. Cost estimate of ductile and conventional walls is evaluated and compared to each other in terms of weight of reinforcement bars. In addition, due to the complexity of design and installation of ductile shear walls, sensitivity analysis is performed as well. It is observed that conventional design considerably increases induced seismic responses as well as cost compared to ductile one.

Seismic performance of a wall-frame air traffic control tower

  • Moravej, Hossein;Vafaei, Mohammadreza;Abu Bakar, Suhaimi
    • Earthquakes and Structures
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    • v.10 no.2
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    • pp.463-482
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    • 2016
  • Air Traffic Control (ATC) towers play significant role in the functionality of each airport. In spite of having complex dynamic behavior and major role in mitigating post-earthquake problems, less attention has been paid to the seismic performance of these structures. Herein, seismic response of an existing ATC tower with a wall-frame structural system that has been designed and detailed according to a local building code was evaluated through the framework of performance-based seismic design. Results of this study indicated that the linear static and dynamic analyses used for the design of this tower were incapable of providing a safety margin for the required seismic performance levels especially when the tower was subjected to strong ground motions. It was concluded that, for seismic design of ATC towers practice engineers should refer to a more sophisticated seismic design approach (e.g., performance-based seismic design) which accounts for inelastic behavior of structural components in order to comply with the higher seismic performance objectives of ATC towers.

Seismic applicability of a long-span railway concrete upper-deck arch bridge with CFST rigid skeleton rib

  • Shao, Changjiang;Ju, Jiann-wen Woody;Han, Guoqing;Qian, Yongjiu
    • Structural Engineering and Mechanics
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    • v.61 no.5
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    • pp.645-655
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    • 2017
  • To determine the seismic applicability of a long-span railway concrete upper-deck arch bridge with concrete-filled steel-tube (CFST) rigid skeleton ribs, some fundamental principles and seismic approaches for long-span bridges are investigated to update the design methods in the current Code for Seismic Design of Railway Engineering of China. Ductile and mixed isolation design are investigated respectively to compare the structural seismic performances. The flexural moment and plastic rotation demands and capacities are quantified to assess the seismic status of the ductile components. A kind of triple friction pendulum (TFP) system and lead-plug rubber bearing are applied simultaneously to regularize the structural seismic demands. The numerical analysis shows that the current ductile layout with continuous rigid frame approaching spans should be strengthened to satisfy the demands of rare earthquakes. However, the mixed isolation design embodies excellent seismic performances for the continuous girder approaching span of this railway arch bridge.

An Experimental Study on the Reinforcement of Low-Rise RC Structure for Seismic Performance (저층 RC 건물의 내진성능 보강에 관한 실험적 연구)

  • Kim, Dongbaek;Lee, Byeonghoon;Kwon, Soondong;Lee, Induk
    • Journal of the Society of Disaster Information
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    • v.12 no.2
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    • pp.144-149
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    • 2016
  • Nowaday, most of the low-rise concrete structures which have less than five stories were built before the intensified seismic code was established 2005. According to the fact that our country is not a safety zone ay more, studies are need to reinforce the seismic performance of that structures. The basic frame of low-rise structure are consist of beams and columns with partition walls, therefore that are very weak about secondary wave of earthquake because of the high stiffness. The partition wall are consist of open channel for sunlight or ventilation and intermediate wall. The intermediate walls will enhance the stiffness of columns, but will cause shear failure with short column effects because of the reduced effective depth. But we don't have studies and adequate design code for partition wall effects, therefore some more studies are need for these facts.

Seismic Evaluation for Strainer in the Primary Cooling System (일차 냉각계통 스트레이너에 대한 내진 건전성 평가)

  • 정철섭
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.13 no.3
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    • pp.295-304
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    • 2000
  • To evaluate the structural integrity for the strainer under seismic loading the seismic analysis and design were performed for T-type strainer in accordance with ASME, Section Ⅲ, Class 3(ND). Since there are no specified design requirements for the strainer in ASME Code, the strainer body was analysed according to ND-3500, valve design. Flanged joints connected with PCS piping were designed according to ND-3658.3. And the criteria for the cover flange was governed by the Appendix XI. Both a frequency analysis and an equivalent static seismic analysis of the strainer were carried out using the finite element computer program, ANSYS. The frequency analysis results show the fundamental natural frequency is greater than 33Hz, thus justifying the use of the equivalent static analysis through which membrane and bending stresses are obtained in the critical points near the branch connection area. The results of the seismic evaluation fully satisfied with the structural acceptance criteria of the ASME Code. Accordingly the structural integrity on the strainer body and flanges were proved.

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