• Steel and Composite Structures
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• 제26권5호
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• pp.573-582
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• 2018

This study develops and numerically verifies an innovative seismically resilient bracing system. The proposed self-centering tension-only brace (SC-TOB) is composed of a tensioning system to provide a self-centering response, a frictional device for energy dissipation, and a high-strength steel cable as a bracing element. It is considered to be an improvement over the traditional self-centering braces in terms of lightness, high bearing capacity, load relief, and double-elongation capacity. In this paper, the mechanics of the system are first described. Governing equations deduced from the developed analytical model to predict the behavior of the system are then provided. The results from a finite element validation confirm that the SC-TOB performs as analytically predicted. Key parameters including the activation displacement and load, the self-centering parameter, and equivalent viscous damping are investigated, and their influences on the system behavior are discussed. Finally, a design procedure considering controlled softening behavior is developed and illustrated through a design example.

• Steel and Composite Structures
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• 제21권4호
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• pp.863-882
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• 2016

This study aims to introduce a new bracing system by which even super-wide frames with large openings can be braced. The proposed system, hereafter called Cable-Pulley Brace (CPB), is a tension-only bracing system with a rectilinear configuration. In CPB, a wire rope passes through a rectilinear path around the opening(s) and connects the lower corner of the frame to its opposite upper one. CPB is a secondary load resisting system with a nonlinear-elastic hysteretic behavior due to its initial pre-tension load. As a result, the required energy dissipation would be provided by the MRF itself, and the main intention of using CPB is to contribute to the initial and post-yield stiffness of the whole system. Using a stiffness calibration technique, optimum placement of the CPBs is discussed to yield a uniform displacement demand along the height of the structure. A displacement-based design procedure is proposed by which the MRF with CPB can be designed to achieve a uniform distribution of inter-story drifts with predefined values. Obtained results indicated that CPB leads to significant reductions in maximum and residual deformations of the MRF at the expense of minor increase in the maximum base shear and developed axial force demands in the columns. In the case of a typical 5-story residential building, compared to SMRF system, CPB system reduces maximum amounts of inter-story and residual drifts by 35% and 70%, respectively. Moreover, openings of the frame are not interrupted by the CPB. This is the most appealing feature of the proposed bracing system from architectural point of view.

• 한국강구조학회 논문집
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• 제21권4호
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• pp.375-384
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• 2009

효과적인 횡력저항 시스템중에 하나인 다이아그리드 구조 시스템의 사용이 늘어나고 있다. 하지만 다이아그리드 노드의 바람 및 지진에 대한 구조성능을 해석적으로 평가하는 것은 한계가 있다. 특히 용접특성의 반영이 어려운데, 이 연구에서는 횡하중을 받는 다이아그리드 노드의 구조적 거동을 알아보기 위해 실제부재의 5분의 1로 축소한 모형을 이용해 실험을 수행했다. 주요 부위의 용접방법, 설계상세등 5가지 변수에 대하여 총 네 개의 실험체를 제작했다. 한쪽 가새부재에는 압축력을, 다른 쪽 가새부재에는 인장력을 가하는 반복가력 실험을 수행했다. 실험 결과 주요 파괴 원인은 인장력과 부가모멘트에 의한 파괴와 인장력만에 의한 용접부의 파단으로 나뉜다. 용접방법과 설계상세에 따른 초기강성, 항복강도의 차이는 없었다. 용접방법에 따른 파괴 형상의 차이가 있었으며 설계상세는 에너지 흡수능력에 영향을 미쳤다.