• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 봄 학술발표회논문집
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• pp.317-323
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• 2000

The purpose of this study is to compare the seismic resistant capacity inherent in ductile moment resisting frames using two different joint modeling. The difference between these two models is the capability for considering the panel zone deformation. For this purpose, 5 story steel moment frame is designed in compliance to the Korean seismic design provisions and the steel structure design standard. Nonlinear Static Procedure(NSP) and Nonlinear Dynamic Procedure(NDP) of this structure are carried out using two different joint models. Based on the results of NSP and NDP, the sensitivity of the response to analytical modeling is appraised. Also, it is proposed that for the highrise steel structures, the joint deformation should be accounted properly by the analytical model.

• Steel and Composite Structures
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• 제13권4호
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• pp.397-408
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• 2012

This paper describes the refined 3-D finite element (FE) modeling of composite frames composed of concrete-filled steel tubular (CFST) columns and steel-concrete composite beams based on the test to get a better understanding of the seismic behavior of the steel-concrete composite frames. A number of material nonlinearities and contact nonlinearities, as well as geometry nonlinearities, were taken into account. The elastoplastic behavior, as well as fracture and post-fracture behavior, of the FE models were in good agreement with those of the specimens. Besides, the beam and panel zone deformation of the analysis models fitted well with the corresponding deformation of the specimens. Parametric studies were conducted based on the refined finite elememt (FE) model. The analyzed parameters include slab width, slab thickness, shear connection degree and axial force ratio. The influences of these parameters, together with the presence of transverse beam, on the seismic behavior of the composite frame were studied. And some advices for the corresponding seismic design provisions of composite structures were proposed.

• 국제강구조저널
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• 제18권4호
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• pp.1464-1469
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• 2018

Steel frames with ductile connections have good seismic performance under strong earthquake, they are now popular for high seismic design. In order to simplify the process of numerical analysis of the steel frames with ductile connections, simplified connection models are introduced, two types of springs are placed in the simplified connection model, which can simulate deformation of the panel zone and members. 6-story-3-bay steel frames with ductile connections are simplified and carried out modal analysis, fundamental periods of the frames predicted by finite-element analysis for simplified steel frame models were compared to the results for actual frame models. 2-story steel frame with reduced beam section connections is simplified and carried out pseudo-static analysis, hysteretic curves and skeleton curves of the frame obtained by finite-element analysis for simplified steel frame model are compared to test results. The comparison show that the difference between them is small, it is reliable and effective to predict mechanical properties of the steel frame with ductile connection by finite-element analysis of simplified steel frame model.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.473-478
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• 2003

The purpose of this study is to model the seismic behavior of Welded Unreinforced Flange and Bolted (WUF-B) connections with post-Northridge details and evaluate the system performance of the builidings with WUF-B connections. For this purpose, based on test results, mathematical model of the connections were developed and compared with test results. This connection model take into account both panel zone deformation and connection fractures. Then, SAC Phase II 3 and 9-story buildings were modeled using the connection model developed in this study. From nonlinear static pushover analysis of the buildings, maximum strength, maximum roof drift, and so forth are investigated for the buildings with post-Northridge details. Analysis results were compared with those of buildings with pre-Northridge details and ductile connections with no fractures.

• Steel and Composite Structures
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• 제43권3호
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• pp.327-340
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• 2022

A vast amount of experimental and analytical research has been conducted related to the seismic behavior and performance of concrete filled steel tubular (CFT) columns. This research has resulted in a wealth of information on the component behavior. However, analytical and experimental data for structural systems with CFT columns is limited, and the well-known behavior of steel or concrete structures is assumed valid for designing these systems. This paper presents the development of an analytical model for nonlinear analysis of composite moment resisting frame (CFT-MRF) systems with CFT columns and steel wide-flange (WF) beams under seismic loading. The model integrates component models for steel WF beams, CFT columns, connections between CFT columns and WF beams, and CFT panel zones. These component models account for nonlinear behavior due to steel yielding and local buckling in the beams and columns, concrete cracking and crushing in the columns, and yielding of panel zones and connections. Component tests were used to validate the component models. The model for a CFT-MRF considers second order geometric effects from the gravity load bearing system using a lean-on column. The experimental results from the testing of a four-story CFT-MRF test structure are used as a benchmark to validate the modeling procedure. An analytical model of the test structure was created using the modeling procedure and imposed-displacement analyses were used to reproduce the tests with the analytical model of the test structure. Good agreement was found at the global and local level. The model reproduced reasonably well the story shear-story drift response as well as the column, beam and connection moment-rotation response, but overpredicted the inelastic deformation of the panel zone.

• 한국강구조학회 논문집
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• 제23권4호
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• pp.405-415
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• 2011

건축물의 안전한 내진설계를 위해서는 층간변위비 뿐만 아니라 부재에 요구되는 소성변형을 평가하여야 한다. 본 연구에서는 복잡한 비선형해석 없이 탄성해석을 사용하여 강기둥-약보로 설계된 철골 특수모멘트골조의 보에 요구되는 소성변형을 평가하는 간편한 방법을 개발하였다. 개발한 방법은 탄성해석 결과를 근거로 모멘트 재분배, 기둥 단면치수 및 보 소성힌지 이동, 패널존 변형, 중력하중, 변형경화 거동 등을 고려하여 보의 소성변형각을 직접적으로 예측한다. 또한 가새골조 또는 코어벽 등 횡력 저항구조와 모멘트골조의 상호 작용인 로킹 효과 고려한다. 검증을 위하여 강기둥-약보로 설계된 6층 특수모멘트골조에 제안된 방법을 적용하여 보의 소성변형각을 예측하고, 그 결과를 비선형 해석 결과와 비교하였다. 검증 결과, 제안된 방법은 설계 변수에 따른 보의 소성변형각을 합리적으로 예측하는 것으로 나타났다.

• Steel and Composite Structures
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• 제17권4호
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• pp.471-495
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• 2014

The responses of steel buildings with perimeter moment resisting frames (PMRF) with medium size columns (W14) are estimated and compared with those of buildings with deep columns (W27), which are selected according to two criteria: equivalent resistance and equivalent weight. It is shown that buildings with W27 columns have no problems of lateral torsional, local or shear buckling in panel zone. Whether the response is larger for W14 or W27 columns, depends on the level of deformation, the response parameter and the structural modeling under consideration. Modeling buildings as two-dimensional structures result in an overestimation of the response. For multiple response parameters, the W14 columns produce larger responses for elastic behavior. The axial load on columns may be significantly larger for the buildings with W14 columns. The interstory displacements are always larger for W14 columns, particularly for equivalent weight and plane models, implying that using deep columns helps to reduce interstory displacements. This is particularly important for tall buildings where the design is usually controlled by the drift limit state. The interstory shears in interior gravity frames (GF) are significantly reduced when deep columns are used. This helps to counteract the no conservative effect that results in design practice, when lateral seismic loads are not considered in GF of steel buildings with PMRF. Thus, the behavior of steel buildings with deep columns, in general, may be superior to that of buildings with medium columns, using less weight and representing, therefore, a lower cost.

• 한국강구조학회 논문집
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• 제23권3호
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• pp.261-273
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• 2011

최근에는 건축물의 대형화, 고층화라는 시대적인 흐름과 요구로 인해서 철골 구조의 수요가 급증하고 있다. 일반적인 철골 구조의 해석은 접합부를 강접합과 단순접합으로 가정하여 수행되고 있는데, 강접합(Fixed connection)의 경우에는 절점에 연결된 각 부재의 변형 전 상대적인 각도가 변형 후에도 그대로 유지된다고 가정하므로 접합부가 충분한 강성을 발휘하고 안정성을 확보하도록 패널존 부분에 스티프너로 보강을 한다. 하지만 인건비 상승과 함께 강접 접합부의 제작비가 과도해짐으로 경제성 측면에서 스티프너 보강을 생략한 접합부의 필요성이 증가하고 있다. 반면, 단순접합(Pinned connection)의 경우에는 단순보처럼 거동하여 보와 기둥 사이에 휨모멘트가 전달되지 않는다고 가정한다. 이는 공장제작이 간단하고, 시공이 간편한 장점이 있으나 접합부에서 모멘트를 전달할 수 없어서 구조적인 효율이 떨어지는 단점이 있다. 반강접의 도입은 단면치수 결정의 효율성을 증대하고, 현장에서의 부재조립 용이성, 골조 전체의 안전성 확보 등의 이점이 있어서 외국의 경우, 보-기둥 접합부의 실제적인 거동을 파악하기 위해서 계속적인 노력을 해왔고 그 결과를 규준에 적용하고 있다. 본 논문은 미국 AISC의 LRFD 설계규준을 참고하여 국내 강재를 적용한 반강접의 구조해석을 실시해서 각 강재에 대한 자료은행을 만들 것이고 이상화된 접합부의 구조해석 결과와 비교하여 경제성 측면, 단부 고정계수, 회전강성과 함께 반강접을 고려한 구조물의 설계 방안을 제시 하고자 한다.