• Structural Engineering and Mechanics
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• 제12권6호
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• pp.573-594
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• 2001

A two-level displacement-based design procedure is developed. To obtain the displacement demands, elastic spectra for occasional earthquakes and inelastic spectra for rare earthquakes are used. Minimum global stiffness and strength to be supplied to the structure are based on specified maximum permissible drift limits and on the condition that the structure responds within the elastic range for occasional earthquakes. The performance of the structure may be assessed by an inelastic push-over analysis to the required displacement and the evaluation of damage indices. The approach is applied to the design of a five-story reinforced concrete coupled wall structure located in the most hazardous seismic region of Argentina. The inelastic dynamic response of the structure subjected to real and artificially generated acceleration time histories is also analyzed. Finally, advantages and limitations of the proposed procedure from the conceptual point of view and practical application are discussed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.498-501
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• 2004

A new slab design using secant stiffness, Direct Inelastic Slab Design, was developed. Since basically the proposed design method uses linear analysis, it is convenient and stable in numerical analysis. At the same time, the proposed design method can accurately estimate the inelastic strength and ductility demands of slab because it can analyzes the inelastic behavior of structure using iterative calculations for secant stiffness. In the present study, the procedure of the proposed design method was established, and a computer program incorporating the proposed method was developed. Design examples using the proposed method were presented, and compared with traditional nonlinear analysis, and experiments. The Direct Inelastic Slab Design, as an integrated analysis/design method, can directly address the design strategy intended by the engineer, such as moment strength and ductility limit. As a result, economical and safe design can be achieved.

• Structural Engineering and Mechanics
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• 제48권5호
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• pp.681-695
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• 2013

Performance-based seismic design allows a structure to develop inelastic response during earthquakes. This modern seismic design requires more clearly defined levels of inelastic response. The ultimate deformation of a structure without total collapse (target displacement) is used to obtain the inelastic deformation capacity (inelastic performance). The inelastic performance of a structure indicates its performance under excitation. In this study, a new energy-based method to obtain the target displacement for reinforced concrete frames under cyclic loading is proposed. Concrete structures were analyzed using nonlinear static (pushover) analysis and cyclic loading. Failure of structures under cyclic loading was controlled and the new method was tested to obtain target displacement. In this method, the capacity energy absorption of the structures for both pushover and cyclic analyses were considered to be equal. The results were compared with FEMA-356, which confirmed the accuracy of the proposed method.

• 한국강구조학회 논문집
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• 제17권1호통권74호
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• pp.103-113
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• 2005

본 연구에서는 선행 연구에서 개발된 강구조물에 대한 직접비탄성설계 방법을 설계실무의 활용성을 확대할 수 있도록 개선하였다. 그룹부재에 대한 설계, 불연속적인 단면 성능, 축력에 따른 휨재하능력의 변화, 접합방식에 따른 거동특성, 다중하중조건 및 성능기준 등 강구조물 설계실무의 제한조건을 고려하여 비탄성설계를 수행할 수 있는 방법을 개발하였다. 본 연구에서는 제안된 방법의 해석 및 설계절차를 정립하였고, 이를 적용한 컴퓨터 해석/설계 프로그램을 개발하였다. 전통적인 탄성설계와 제안된 직접비탄성설계법을 사용한 설계결과를 비교하였으며, 기존의 비선형해석프로그램을 이용하여 설계결과를 검증하였다. 비탄성 변형을 고려할 수 있는 제안된 설계법은 전통적인 탄성해석을 사용한 한계상태설계에 비하여 강재량을 절감하고, 구조물의 변형능력을 향상하였다. 제안된 설계방법은 비탄성 거동을 구조물의 설계에 직접 반영할 수 있으므로 설계에 편리하고 각 소성힌지의 변형을 제어함으로써 구조안전성을 확보하고 동시에 변형능력을 최대로 활용하는 설계를 수행할 수 있다.

• Earthquakes and Structures
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• 제15권2호
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• pp.155-164
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• 2018

Design of structures subjected to blast loads are usually carried out through nonlinear inelastic dynamic analysis followed by imposing acceptance criteria specified in design codes. In addition to comprehensive aspects of inelastic dynamic analyses, particularly in analysis and design of structures subjected to transient loads, they inherently suffer from convergence and computational cost problems. In this research, a strategy is proposed for design of steel moment resisting frames under far range blast loads. This strategy is inspired from performance based seismic design concepts, which is here developed to blast design. For this purpose, an algorithm is presented to calculate the capacity modification factors of frame members in order to simplify design of these structures subjected to blast loading. The present method provides a simplified design procedure in which the linear dynamic analysis is preformed, instead of the time-consuming nonlinear dynamic analysis. Nonlinear and linear analyses are accomplished in order to establish this design procedure, and consequently the final design procedure is proposed as a strategy requiring only linear structural analysis, while acceptance criteria of nonlinear analysis is implicitly satisfied.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1991년도 봄 학술발표회 논문집
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• pp.72-78
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• 1991

An improved procedure for earthquake resistant design of multistory building structures is proposed in this study. The effect of gravity load on seismic response of structures is evaluated through nonlinear dynamic analyses of a single story example structure. The presence of gravity load tends to initiate plastic hinge formation in earlier stage of a strong earthquake. However, the effect of gravity load seems to disapper as ground motion is getting stronger. And one of shortcomings in current earthquake resistant codes is overestimation of gravity load effects when earthquake load is applied at the same time so that it may leads to less inelastic deformation or structural damage in upper stories, and inelastic deformation is increased in lower stories. Based on these observation, an improved procedure for earthquake resistant design is derived by reducing the factor for gravity load and inceasing that for seismic load. Structures designed by the proposed design procedure turned out to have increased safety and stability against strong earthquakes.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.971-976
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• 2006

This paper presents a design technique of steel structures subjected to static and dynamic loadings using practical nonlinear inelastic analysis software. The beam-column approach using the stability functions and the plastic hinge concept enables the software to suitably predict second-order effects and inelastic behavior of beam-columns. For dynamic analysis. the incremental from of the equation of motion is solved by the use of a step-by-step numerical integration procedure in which the assumption of constant acceleration over a small time step is employed. The accuracy of the analysis program is validated using the results of ABAQUS program and experimental tests. A user-friendly graphic interface of the software is developed to facilitate the modeling process and result interpretation of the problem. A design example of large span bridge is presented to detail the direct design process using the practical advanced analysis software.

• Steel and Composite Structures
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• 제7권6호
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• pp.421-440
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• 2007

An optimal design method in cooperated with nonlinear inelastic analysis is presented. The proposed nonlinear inelastic method overcomes the difficulties due to incompatibility between the elastic global analysis and the limit state member design in the conventional LRFD method. The genetic algorithm used is a procedure based on Darwinian notions of survival of the fittest, where selection, crossover, and mutation operators are used to look for high performance ones among sections in the database. They are satisfied with the constraint functions and give the lightest weight to the structure. The objective function taken is the total weight of the steel structure and the constraint functions are load-carrying capacity, serviceability, and ductility requirement. Case studies of a planar portal frame, a space two-story frame, and a three-dimensional steel arch bridge are presented.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.145-152
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• 2003

An optimal design method in cooperated with nonlinear inelastic analysis method is presented. The proposed nonlinear inelastic method overcomes the difficulties due to incompatibility between the elastic global analysis and the limit state member design in the conventional LRFD method. The genetic algorithm uses a procedure based on Darwinian notions of survival of the fittest, where selection, crossover, and mutation operators are used among sections in the database to look for high performance ones. They satisfy the constraint functions and give the lightest weight to the structure. The objective function is set to the total weight of the steel structure and the constraint functions are load-carrying capacities, serviceability, and ductility requirement. Case studies of a three-dimensional frame and a three-dimensional steel arch bridge are presented.

• 한국지진공학회논문집
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• 제15권6호
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• pp.45-53
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• 2011

본 연구의 목적은 마찰 감쇠기를 사용한 기존 구조물의 제진보강 설계절차를 제시하는 것이다. 보강된 구조물의 목표 지붕층 변위는 기존 구조물이 급격한 강도의 저감없이 보유내력을 발휘할 수 있는 최대변위를 초과하지 않도록 결정하였다. 보강 구조물의 변위는 비탄성 변위비 제안식을 이용하여 예측하였다. 제안된 방법의 유효성을 검증하기 위하여 80개의 지반운동 데이터를 사용하여 비선형 동적해석을 수행하였다. 해석결과 제안된 방법은 보강 구조물의 지붕층 변위를 정확히 예측할 수 있는 것으로 나타났다.