• Structural Engineering and Mechanics
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• 제1권1호
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• pp.31-46
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• 1993

The motivations of the application of shakedown analysis to the earthquake-resistant design of ductile moment-resisting steel structures are presented. The problems which must be solved with this application are also addressed. The illustrative results from a series of static and time history nonlinear analyses of one-bay three-story steel frame and the related discussions have shown that the incremental collapse may be the critical design criterion in case of earthquake loading. Based on the findings, it was concluded that the inelastic excursion mechanism for alternation load pattern, such as in earthquake, should be the sidesway mechanism of the whole structure for the efficient mobilization of the structural energy dissipating capacity and that the shakedown analysis technique can be used as a tool to ensure this mechanism.

• 한국공간구조학회논문집
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• 제17권4호
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• pp.35-42
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• 2017

This study develops a new hybrid passive energy dissipation device for seismic rehabilitation of an existing structure. The device is composed of a friction damper combined with a steel plate with vertical slits as a hysteretic damper. Analytical model is developed for the device, and the capacity of the hybrid device to satisfy a given target performance is determined based on the ASCE/SEI 7-10 process. The effect of the device is verified by nonlinear dynamic analyses using seven earthquake records. The analysis results show that the dissipated inelastic energy is concentrated on the hybrid damper and the maximum interstory drift of the SMRF with damping system satisfies the requirement of the current code.

• 한국공간구조학회:학술대회논문집
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• 한국공간구조학회 2005년도 춘계학술발표회 및 정기총회 2권1호(통권2호)
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• pp.175-182
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• 2005

The purpose of this study is to investigate experimentally the shear resisting behavior of the reinforced concrete beams strengthened with reinforcement materials(CFRP). Ten specimens were manufactured and tested under static monotonic loading. The main variables in the test were a space of steel reinforcement and direction of CFRP reinforcement. The test result Indicated that the method of CFRP increase significantly the shear strength of a reinforced concrete beam

• 한국공간구조학회:학술대회논문집
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• 한국공간구조학회 2005년도 춘계학술발표회 및 정기총회 2권1호(통권2호)
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• pp.183-190
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• 2005

이 연구의 목적은 CFRP로 보강된 철근콘크리트 보의 전단저항거동을 실험적으로 연구하는데 있다. 6개의 시험체를 제작하여 정적하중을 단조재하 하에 실험하였다. 실험의 주된 변수는 보강재의 좌강간격 및 비(량)을 두어 실험을 실시하였다. 본 연구의 목적은 CFRP-rod를 사용한 매립공법에 의한 전단보강효과를 파악하고자 한다. 이 실험의 결과는 CFRP의 보강된 철근콘크리트 보의 극한 전단강도가 증가하는 것을 나타내고 있다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.98-99
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• 2018

Seismic retrofitting technologies have been paid attention to structural engineers for rehabilitations of existing building structures vulnerable to seismic loading conditions. This paper introduces the traditional strengtheing method applying externally-bonded steel frames to column and beam elements, and compares with the improved scheme using the frames with additional energy dissipation systems. Throughout experimental studies, it was observed that the method can be effective for promoting the seismic performance of seismic force-resisting systems by guaranteeing strong column-weak beam mechanism. Compared to the traditional manner, it was found that the new scheme can be more efficient for confirming capacity design concept, while energy dissipation systems can provide additional damping effects corresponding to lateral deformation which occurs at seismic force-resisting systems exposed to seismic excitations.

• Steel and Composite Structures
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• 제51권5호
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• pp.487-498
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• 2024

Steel moment resisting frames (MRFs) typically have inter-story drift concentrations at lower stories during earthquakes as found from previous research. Hinged walls (HWs) can be used as structural strengthening components to force the MRFs deform uniformly along the building height. However, large moment demands are often observed on HWs and make the design of HWs non-economical. This paper proposes a method to reduce the moment demand on HWs using a ductile connection system between the MRFs and the HWs. The ductile connection system is designed with a yield strength and energy dissipation capacity, for the purpose of limiting the seismic forces transferred to the HWs and dissipating seismic energy. Nonlinear time history analyses were performed using 10 far-filed earthquakes at maximum considered earthquake level. The analysis results show that the proposed ductile connection system can reduce: (1) seismic moment demands in the HWs; (2) floor accelerations; (3) the connection force between HWs and MRFs.

• Steel and Composite Structures
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• 제34권1호
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• pp.107-122
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• 2020

Moment resisting stub columns (MRSCs) have increasingly adopted in special moment-resisting frame (SMF) systems in steel building structures, especially in Asian countries. The MRSCs typically provide a lower deformation capacity compared to shear-panel stub columns, a limited post-yield stiffness, and severe strength degradation as adopting slender webs. A new MRSC design with cored configuration, consisting of a core-segment and two side-segments using different steel grades, has been proposed in the study to improve the demerits mentioned above. Several full-scale components of the cored MRSC were experimentally investigated focusing on the hysteretic performance of plastic hinges at the ends. The effects of the depths of the core-segment and the adopted reduced column section details on the hysteretic behavior of the components were examined. The measured hysteretic responses verified that the cored MRSC enabled to provide early yielding, great ductility and energy dissipation, enhanced post-yield stiffness and limited strength degradation due to local buckling of flanges. A parametric study upon the dimensions of the cored MRSC was then conducted using numerical discrete model validated by the measured responses. Finally, a set of model equations were established based on the results of the parametric analysis to accurately estimate strength backbone curves of the cored MRSCs under increasing-amplitude cyclic loadings.

• 한국지진공학회논문집
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• 제16권4호
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• pp.1-8
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• 2012

국내 철골모멘트골조를 이전 KBC2005 및 현 KBC2009 기준에 따라 설계한 후 비선형동적해석을 이용하여 FEMA355F의 내진성능평가 절차에 따라 성능을 평가하였다. 그 결과 비선형정적 Push-over 해석을 이용한 역량스펙트럼법과 차이가 있었다. 특히 국내 철골모멘트골조는 약패널존을 가지기 때문에 비선형동적해석을 통해서만 보다 정확한 거동을 예측할 수 있었다. 국내 철골모멘트골조는 지반 조건 SB 또는 SC에 위치한다면 층수 및 R값에 관계없이 성능목표를 만족하는 것으로 나타났다. 하지만 지반 조건 SD 또는 SE에 위치한다면 성능목표 만족 여부는 명확하지 않았다. 따라서 KBC2005나 KBC2009 어떤 기준을 사용하더라도 지반 조건이 상대적으로 좋다면 국내 철골모멘트골조는 내진성능을 충분히 확보하고 있다고 볼 수 있다.

• 한국산학기술학회논문지
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• 제15권2호
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• pp.1164-1169
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• 2014

해마다 태풍과 같은 자연재해에 의해 경사지에 설치된 전주의 전도피해가 발생하고 있지만, 현행 전주설계 기준에는 경사지에서의 전도안전율에 대한 기준이 미비하다. 본 연구에서는 설계기준의 기본개념을 적용하여 경사지에서의 지반 저항모멘트를 범용 해석 프로그램 L-Pile Plus13.8로 해석하여 산정하였다. 현 설계기준이 제시하는 보정근입깊이를 적용하더라도 경사지의 지반 저항모멘트는 지반경사각이 클수록 크게 감소하였다. 경사지에 설치된 전주가 평지에 설치된 전주와 같은 정도의 지반 저항모멘트를 갖기 위해서는 현행 경사지 보정근입깊이에 1.5~3배 증가시킬 필요가 있는 것으로 연구되었다.

• Earthquakes and Structures
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• 제12권1호
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• pp.23-34
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• 2017

Composite steel plate deep beam (CDB) is proposed as a lateral resisting member, which is constructed by steel plate and reinforced concrete (RC) panel, and it is connected with building frame through high-strength bolts. To investigate the seismic performance of the CDB, tests of two 1/3 scaled specimens with different length-to-height ratio were carried out under cyclic loads. The failure modes, load-carrying capacity, hysteretic behavior, ductility and energy dissipation were obtained and analyzed. In addition, the nonlinear finite element (FE) models of the specimens were established and verified by the test results. Besides, parametric analyses were performed to study the effect of length-to-height ratio, height-to-thickness ratio, material type and arrangement of RC panel. The experimental and numerical results showed that: the CDBs lost their load-carrying capacity because of the large out-of plane deformation and yield of the tension field formed on the steel plate. By increasing the length-to-height ratio of steel plate, the load-carrying capacity, elastic stiffness, ductility and energy dissipation capacity of the specimens were significantly enhanced. The ultimate loading capacity increased with increasing the length-to-height ratio of steel plate and yield strength of steel plate; and such capacity increased with decreasing of height-to-thickness ratio of steel plate and gap. Finally, a unified formula is proposed to calculate their ultimate loading capacity, and fitting formula on such indexes are provided for designation of the CDB.