• Steel and Composite Structures
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• 제11권1호
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• pp.77-91
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• 2011

This study experimentally evaluated the seismic performance of steel knee braced frame structures with energy dissipation mechanism. A series of cyclic load tests were conducted on the steel moment resisting frames and the proposed knee braced frames. Test results validated that the demand in the beam-to-column connection designs was alleviated by the proposed design method. Test results also showed that the strength and stiffness of the proposed design were effectively enhanced. Comparisons in energy dissipation between the steel moment resisting frames and the steel knee braced frames further justified the applicability of the proposed method.

• 한국구조물진단유지관리공학회 논문집
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• 제9권1호
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• pp.171-180
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• 2005

본 연구에서는 기름이나 가스의 송유관을 지지하기 위하여 일반적으로 사용되는 3층의 Knee brace가 설치된 모멘트저항골조(KBMRF)의 내진성능을 평가하였다. KBMRF의 하중-변위 관계를 관찰하기 위하여 비선형 정적 pushover 해석을 수행하였다. 최대층간변위가 층높이의 1.5%에 도달하였을 때 보와 기둥과 같은 주요 구조부재는 탄성상태를 유지하는 것으로 나타났다. UBC-97의 설계스펙트럼에 부합되도록 조정한 8개의 지진기록을 이용하여 비선형 동적시간이력해석을 수행한 결과에 따르면, 최대층간변위는 구조물 높이의 1.5% 변위한계보다 작았고 기둥은 탄성적으로 거동하였다. 따라서 본 연구에서 고려한 KBMRF 구조물의 내진성능은 내진설계기준에서 규정한 모든 요구사항을 만족하는 것으로 나타났다.

• Steel and Composite Structures
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• 제37권2호
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• pp.175-191
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• 2020

In this article, for the first time, the seismic behavior of elliptic-braced moment resisting frame (ELBRF) is assessed through a laboratory program and numerical analyses of FEM specifically focused on the development of global- and local-type failure mechanisms. The ELBRF as a new lateral braced system, when installed in the middle bay of the frames in the facade of a building, not only causes no problem to the opening space of the facade, but also improves the structural behavior. Quantitative and qualitative investigations were pursued to find out how elliptic braces would affect the failure mechanism of ELBRF structures exposed to seismic action as a nonlinear process. To this aim, an experimental test of a ½ scale single-story single-bay ELBRF specimen under cyclic quasi-static loading was run and the results were compared with those for X-bracing, knee-bracing, K-bracing, and diamond-bracing systems in a story base model. Nonlinear FEM analyses were carried out to evaluate failure mechanism, yield order of components, distribution of plasticity, degradation of structural nonlinear stiffness, distribution of internal forces, and energy dissipation capacity. The test results indicated that the yield of elliptic braces would delay the failure mode of adjacent elliptic columns and thus, help tolerate a significant nonlinear deformation to the point of ultimate failure. Symmetrical behavior, high energy absorption, appropriate stiffness, and high ductility in comparison with the conventional systems are some of the advantages of the proposed system.