• Earthquakes and Structures
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• 제14권3호
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• pp.241-248
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• 2018

To study the mechanical properties of joints in ancient timber buildings in depth, the force mechanism of the through-tenon joints was analyzed, also the theoretical formulas of the moment-rotation angles of the joints with different loosening degrees were deduced. To validate the rationality of the theoretical calculation formulas, six joint models with 1/3.2 scale ratio, including one intact joint and five loosening joints, were fabricated and tested under cyclic loading. The specimens underwent the elastic stage, the plastic stage and the destructive stage, respectively. At the same time, the moment-rotation backbone curves of the tenon joints with different looseness were obtained, and the theoretical calculation results were validated when compared with the experimental results. The results show that the rotational moment and the initial rotational stiffness of the tenon joints increase gradually with the increase of the friction coefficient. The increase of the tenon section height can effectively improve the bearing capacity of the through-tenon joints. As the friction coefficient of the wood and the insertion length of the tension increase, the embedment length goes up, whereas it decreases with the increase of section height. With the increase of the looseness, the bearing capacity of the joint is reduced gradually.

• Steel and Composite Structures
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• 제29권6호
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• pp.717-734
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• 2018

This paper presents the flexural performance of steel beam-to-column joints composed of hollow structural section beams and columns. A finite element (FE) model was developed incorporating geometrical and material nonlinearities to evaluate the behaviour of joints subjected to bending moments. The numerical outcomes were validated with experimental results and compared with EN1993-1-8. The demountability of the structure was discussed based on the tested specimen. A parametric analysis was carried out to investigate the effects of steel yield strength, end-plate thickness, beam thickness, column wall thickness, bolt diameter, number of bolts and location. Consequently, an analytical model was derived based on the component method to predict the moment-rotation relationships for the sub-assemblies with extended end-plates. The accuracy of the proposed model was calibrated by the experimental and numerical results. It is found that the FE model is fairly reliable to predict the initial stiffness and moment capacity of the joints, while EN1993-1-8 overestimates the initial stiffness extensively. The beam-to-column joints are shown to be demountable and reusable with a moment up to 53% of the ultimate moment capacity. The end-plate thickness and column wall thickness have a significant influence on the joint behaviour, and the layout of double bolt-rows in tension is recommended for joints with extended end-plates. The derived analytical model is capable of predicting the moment-rotation relationship of the structure.

• 한국강구조학회 논문집
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• 제19권6호
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• pp.715-723
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• 2007

본 연구에서는 중/저층의 철골모멘트골조를 대상으로 합리적이고 실용적인 변위기반 내진설계절차를 제시하였다. 현행의 내진설계에서는 구조시스템 종별에 따라 경험적이고 획일적으로 규정된 반응수정계수를 토대로 설계가 수행되므로, 접합부가 보유한 회전능력의 적정성 여부를 검증하기가 어렵다. 본 논문에서는 실험적으로 입증된 철골모멘트골조 접합부의 가용 소성회전능력을 주요설계변수로 직접 사용하는 새로운 설계법을 제시하였다. 이 설계방안의 정립을 위해, 우선 지금까지 불분명한 관계로 남아있던 접합부의 가용 소성회전능력과 반응수정계수 사이의 관계를 합리적이고 정량적으로 정의하는 방안을 제시하였다. 이를 토대로 변위에 기반한 단계별 내진설계절차를 제시하고 비선형동적해석에 의해 방안의 타당성을 입증하였다.

• Steel and Composite Structures
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• 제20권3호
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• pp.469-486
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• 2016

Codes EN 1993 and EN 1994 require to take into account actual joint characteristics in the global analysis. In order to implement the semi-rigid connection effects in frame design, knowledge of joint rotation characteristics ($M-{\phi}$ relationship), or at least three basic joint properties, namely the moment resistance $M_R$, the rotational stiffness $S_j$ and rotation capacity, is required. To avoid expensive experimental tests many methods for predicting joint parameters were developed. The paper presents a comprehensive analytical model that has been developed for predicting the moment resistance $M_R$, initial stiffness $S_{j.ini}$ and rotation capacity of the minor axis, composite, semi-rigid joint. This model is based on so-called component method included in EN 1993 and EN 1994. Comparison with experimental test results shows that a quite good agreement was achieved. A computer program POWZ containing proposed procedure were created. Based on the numerical simulation made with the use of this program and applying regression analysis, simplified equations for main joint properties were also developed.

• Structural Engineering and Mechanics
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• 제87권1호
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• pp.19-28
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• 2023

This paper describes the experimental investigation of steel pallet rack beam-to-column connec-tions. Total behavior of moment-rotation (M-φ) curve and the effect of particular characteristics on the behavior of connection were studied and the associated load strain relationship and corre-sponding failure modes are presented. In this respect, an estimation of SPRBCCs moment and rotation are highly recommended in early stages of design and construction. In this study, a new approach based on Support Vector Machines (SVMs) coupled with discrete wavelet transform (DWT) is designed and adapted to estimate SPRBCCs moment and rotation according to four input parameters (column thickness, depth of connector and load, beam depth,). Results of SVM-WAVELET model was compared with genetic programming (GP) and artificial neural networks (ANNs) models. Following the results, SVM-WAVELET algorithm is helpful in order to enhance the accuracy compared to GP and ANN. It was conclusively observed that application of SVM-WAVELET is especially promising as an alternative approach to estimate the SPRBCCs moment and rotation.

• Steel and Composite Structures
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• 제1권4호
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• pp.441-458
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• 2001

We analyzed the experimental and theoretical behavior of a particular type of steel joint designed to connect beam to beam and able to transfer both shear forces and bending moments. This joint is characterized by the use of steel plates and bolts enclosed in the width of the beams. The experimental investigation was carried out characterizing the constituent materials and testing in flexure beams constituted by two portions of beams connected in the middle with the joint proposed. Connections having different characteristics in terms of thickness of plates, number and type of bolts were utilized. Flexure tests allow one to determine the loaddeflection curves of the beam tested and the moment-rotation diagrams of the connections, highlighting the strength and the strain capacity of the joints. The proposed analytical model allows one to determine the moment-rotation relationship of the connections, pointing out the influence of the principal geometrical and mechanic characteristics of single constituents on the full properties of the joint.

• 한국터널지하공간학회 논문집
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• 제23권2호
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• pp.93-106
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• 2021

일반적으로 세그먼트 라이닝 터널은 프리캐스트 콘크리트 세그먼트를 연결하여 하나의 링을 구성하고 터널의 진행방향으로 링을 서로 결합하여 형성한 터널을 말한다. 세그먼트 라이닝의 구조적 특성은 세그먼트 이음부의 거동에 따라 크게 달라지므로 이음부를 적절하게 모델링해야 한다. 지반 하중을 받을 때 세그먼트 이음부는 회전에 저항하는 힌지로 작동하며, 모멘트-회전 관계는 비선형 거동을 보인다. 세그먼트 이음부가 라이닝 거동에 미치는 영향을 파악하기 위해 실제 설계에 통용되는 일본 기준 및 Janssen 모델을 적용하여 세그먼트 이음부의 모멘트-회전 관계를 설정하였다. 또한 이 논문은 지압강도를 기초로 세그먼트 이음부의 회전강성을 결정하는 방법을 제시하였다. 가상의 설계조건에서 기존 모델 및 제시된 방법을 적용해 세그먼트 이음부의 회전을 추정하고 세그먼트 라이닝과 이음부에서 발생하는 단면력을 계산하였다. 세그먼트 이음부의 회전이 증가할수록 이음부의 접촉 면적이 감소하므로 세그먼트 이음부의 지압강도를 확인해야 한다. 이 논문은 세그먼트 이음부의 지압강도를 검토하기 위해 세그먼트 이음부의 회전강성을 결정하고 지압강도를 계산하는 일관된 방법을 제시하였다.

• Structural Engineering and Mechanics
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• 제87권4호
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• pp.391-403
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• 2023

In this study, a new type of self-centering beam-column joint with tapered steel plate links is proposed. Firstly, mechanical property of the basic joint (with the prestressed steel strands only, to provide the self-centering ability) and the combined joint (with both the prestressed steel strands and tapered steel plate links, to provide self-centering and energy dissipation simultaneously) is theoretically analyzed. Then, three joints with different dimensions and combinations of tapered plate links are designed and tested through a series of quasi-static cyclic loading tests. Test results show that a nearly bilinear elastic moment-rotation relationship for the basic joint is obtained. With the addition of tapered steel plate links, typical flag-shape hysteretic curves are obtained, which indicates good self-centering and energy dissipating ability of the combined joint. By installing multiple tapered plate links, stiffness and bearing capacity of the beam-column joint can be enhanced. The theoretical moment-rotation relationships agree well with the test results. A simplified macro model of the proposed joint is developed using OpenSees, which simulates reasonably well its hysteretic behavior.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 가을 학술발표회논문집
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• pp.190-197
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• 2000

A moment-curvature relationship to simulate the behavior of reinforced concrete beam under cyclic loading is introduced. Unlike previous moment-curvature models and the layered section approach, the proposed model takes into consideration the bond-slip effect by using monotonic moment-curvature relationship constructed on the basis of the bond-slip relation and corresponding equilibrium equation at each nodal point. In addition, the use of curved unloading and reloading branches inferred from the stress-strain relation of steel gives more exact numerical result. The advantages of the proposed model, comparing to layered section approach, may be on the reduction in calculation time and memory space in case of its application to large structures. The modification of the moment-curvature relation to reflect the fixed-end rotation and pinching effect is also introduced. Finally, correlation studies between analytical results and experimental studies are conducted to establish the validity of the proposed model.

• 콘크리트학회논문집
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• 제23권6호
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• pp.731-740
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• 2011

KCI 2007, ACI 318-08에 제시된 모멘트재분배 방법은 등분포 중력하중을 받는 연속 휨재에 대하여 검증된 방법이다. 횡하중에 의한 모멘트재분배 및 비탄성 거동은 중력하중과 전혀 다른 메커니즘을 발생된다. 이 연구에서는 기초역학에 근거하여 중력하중과 횡하중을 받는 철근콘크리트 모멘트골조의 보에 발생되는 모멘트재분배와 소성변형의 관계를 정량화하고, 이로부터 보의 소성변형능력에 근거한 모멘트재분배 설계법을 제안하였다. 제안된 모멘트재분배비는 KCI 2007, ACI 318-08 등 기존 설계기준과 마찬가지로 극한한계상태의 단면해석으로 결정되는 철근의 인장변형률로 정의된다. 또한 모멘트재분배비는 경간, 철근비, 단면강성, 변형경화 거동에 의하여 영향을 받는다. 제안된 방법을 사용하여 탄성해석으로 구한 설계모멘트를 재분배시키는 설계 가이드라인 및 예제를 제시하였다.