• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1997년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 1997
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• pp.201-208
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• 1997

In most seismic codes such as the Uniform Building Code(UBC), the response modification factor(or the force reduction factor)is used to reflect the capability of a structure in dissipating energy through inelastic behavior. The response modification factor is assigned according to structural system type. Ductile systems such as special moment-resisting steel frames are assigned larger values of the response modification factor, and are consequently designed for smaller seismic design forces. Therefore, structural damage may occur during a severe earthquake. To ensure safety of the structures, the suitability of the response modification factor used in aseismic design procedures shall be evaluated. The object of this study is to develop a method for the evaluating of the response modification factor. The validity of the evaluating method has been examined for several cases of different structures and different earthquake excitations.

• 한국구조물진단유지관리공학회 논문집
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• 제5권1호
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• pp.169-175
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• 2001

Bridge load rating calculations provide a basis for determining the safe load capacity of bridge. Load rating requires engineering judgement in determining a rating value that is applicable to maintaining the safe use of the bridge and arriving at posting and permit decisions. Load testing is an effective means in calculating the rating value of bridge. In Korea, load carrying capacity of bridge is modified by response modification factor that is determined from comparisons of measured values and analysis results. The response modification factor may be corrupted by vehicle location error that is defined as the gap of test vehicle location between load testing and analysis. In this study, the effects of vehicle location error to structural response and response modification factor are investigated, and a new method for evaluating response modification factor is proposed. The random data analysis shows that the proposed method is less sensitive to vehicle location error than the present method.

• 한국지진공학회논문집
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• 제15권1호
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• pp.39-48
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• 2011

본 연구에서는 복강판-모듈러 시스템과 같이 구조 기준에 명시되지 않은 새로운 시스템의 반응수정계수를 산정하는 절차를 제안하였다. 기본 개념은 구조성능 실험결과를 바탕으로 모델링 된 시스템의 비선형 정적 해석 곡선으로부터 세부 구성요소인 초과강도계수와 연성계수의 도출하고, 단자유도 시스템으로 간주하고 평가된 반응수정계수를 다자유도 동적 거동을 고려한 다자유도 밑면전단 수정계수로 수정하여 시스템의 최종적인 반응수정계수를 결정하는 것이다. 제안한 절차에 따라 이중골조시스템으로 설계된 2층부터 5층까지의 복강판-모듈러 시스템에 대해 평가한 결과, 최종적인 반응수정계수는 5층(층고 4m기준)을 복강판-모듈러 시스템의 적용 가능한 층수의 상한으로 하여 4로 결정하는 것이 타당할 것으로 판단하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.161-166
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• 2002

The modification factor( k-factor) of equivalent damping ratio utilized in the current state-of-the-practice to account for the imperfection of reinforced concrete structures in hysteresis loop is investigated. From this, it is found that the current modification factor does not include the effect of cyclic loading, one of the important characteristic properties of earthquake loading. This could be taken into account by considering the energy absorption efficiency based on the cummulative plastic deformation. From the study, it is suggested that the current approach for the modification factor for the equivalent damping ratio should be reformed.

• Steel and Composite Structures
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• 제14권6호
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• pp.621-636
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• 2013

Response modification factor is one of the seismic design parameters to consider nonlinear performance of building structures during strong earthquake, in conformity with the point that many seismic design codes led to reduce the loads. In the present paper it's tried to evaluate the response modification factors of dual moment resistant frame with buckling restrained braced (BRB). Since, the response modification factor depends on ductility and overstrength; the nonlinear static analysis, nonlinear dynamic analysis and linear dynamic analysis have been done on building models including multi-floors and different brace configurations (chevron V, invert V, diagonal and X bracing). The response modification factor for each of the BRBF dual systems has been determined separately, and the tentative value of 10.47 has been suggested for allowable stress design method. It is also included that the ductility, overstrength and response modification factors for all of the models were decreased when the height of the building was increased.

• Steel and Composite Structures
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• 제11권4호
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• pp.273-290
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• 2011

In current ductility-based earthquake-resistant design, the estimation of design forces continues to be carried out with the application of response modification factors on elastic design spectra. It is well-known that the response modification factor (R) takes into account the force reduction, strength, redundancy, and damping of structural systems. The key components of the response modification factor (R) are force reduction ($R_{\mu}$) and strength ($R_S$) factors. However, the response modification and strength factors for structural systems presented in design codes were based on professional judgment and experiences. A numerical study has been accomplished to evaluate force reduction, strength, and response modification factors for special steel moment resisting frames. A total of 72 prototype steel frames were designed based on the recommendations given in the AISC Seismic Provisions and UBC Codes. Number of stories, soil profiles, seismic zone factors, framing systems, and failure mechanisms were considered as the design parameters that influence the response. The effects of the design parameters on force reduction ($R_{\mu}$), strength ($R_S$), and response modification (R) factors were studied. Based on the analysis results, these factors for special steel moment resisting frames are evaluated.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 2002년도 학술대회지
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• pp.424-455
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• 2002

Diabetes mellitus is reaching epidemic proportions worldwide. The insufficiency of medication to cope with this burden has coincided with a dramatic rise in the prevalence of use of complementary and alternative therapies, especially herbal treatments. This surge in demand presents a challenge to prove the safety and efficacy of these treatments in diabetes. Korean red ginseng (steam treated Panax ginseng C.A. Meyer) is a strong candidate to succeed. It has been shown to possess a multitude of hypoglycemic effects and improve metabolic disturbances related to diabetes in in vitro and animal models. Data in humans is also emerging to support these benefits. Whether these results can be replicated in a rigorous clinical testing program is unclear. We therefore investigated the antidiabetic effects of Korean red ginseng in a series of 2 acute and 1 longterm randomized, double-blinded, placebo-controlled clinical trials. This paper provides the rationale for this program of study, expanding on the problem of diabetes, its management, and the possible role for Korean red ginseng. It then describes the design and expected findings.

• Steel and Composite Structures
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• 제48권3호
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• pp.353-365
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• 2023

Shape memory alloys (SMAs) have emerged as a novel functional material that is being increasingly applied in diverse fields including medical, aeronautical and structural engineering to be used in the active, passive and semi-active structural control devices. This paper is mainly aimed at evaluating the ductility and response modification factor of the steel plate shear wall (SPSW) frames with and without the Ni-Ti shape memory alloys. To this end, different configurations were utilized, in which the walls were used in the first, third, middle, and all stories. The models were numerically analyzed using OpenSees Software. The obtained results indicate that improving the shape memory properties of alloys can greatly enhance the ductility and response modification factor. Furthermore, the model whose first and third stories are equipped with the SMA shear wall was found to be 290% more ductile, with a greater response modification factor compared to the unequipped frame.

• Steel and Composite Structures
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• 제19권6호
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• pp.1449-1466
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• 2015

Mixed structures consist of two parts: a lower part and an upper part. The lower part is usually made of concrete while the upper part is made of steel. Analyzing these structures is complicated and code-based design of them has many associated problems. In this research, the seismic behavior of mixed structures which have reinforced concrete frames and shear walls in their lower storeys and steel frames with bracing in their upper storeys were studied. For this purpose, seventeen structures in three groups of 5, 9 and 15 storey structures with different numbers of concrete and steel storeys were designed. Static pushover analysis, linear dynamic analysis and incremental dynamic analysis (IDA) using 15 earthquake records were performed by OpenSees software. Seismic parameters such as period, response modification factor and ductility factor were then obtained for the mixed (hybrid) structures using more than 4600 nonlinear dynamic analysis and used in the regression analysis for achieving proper formula. Finally, some formulas, effective in designing such structures, are presented for the mentioned parameters. According to the results obtained from this research, the response modification factor values of mixed structures are lower compared to those of steel or concrete ones with the same heights. This fact might be due to the irregularities of stiffness, mass, etc., at different heights of the structure. It should be mentioned that for the first time, the performance and seismic response of such structures were studied against real earthquake accelerations using nonlinear dynamic analysis, andresponse modification factor was obtained by IDA.

• Structural Engineering and Mechanics
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• 제86권2호
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• pp.277-290
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• 2023

A supplementary reinforced concrete wall can be used to improve the seismic behavior of a buckling restrained braced frame as a mixed system. In such a novel system, the total lateral force is resisted by the combination of the RC wall system and the BRBF. There is not enough research on the response modification factor of such a mixed system. This paper investigates the response modification factor, and such relevant factors as ductility reduction factor and over strength factor for a system consisting of reinforced concrete wall and buckling restrained braced frame. To this purpose, nonlinear incremental dynamic analysis as well as static push over analysis are used for 6- to 14-story sample structures. The results show that for mixed considered systems, the mean value of response modification factor varies approximately from 7 to 9.