No description available.

The behaviour of limited subassemblages with flexible beans and semi-rigid beam to column connections was studied using a computer program in which the finite element method was employed in a non-linear analysis which accounts for the presence of semi-rigid connections and the inelastic behaviour of frames. The program accounts for many other factors such as initial imperfections and residual stresses. The theoretical background to the present computer program has been presented along with the program layout. The program was used to simulate some of the experimental results obtained from tests on rigidly and flexibly connected frames with different combinations of beam and column loads. The analytical results were found to compare reasonably well with the experimental results. The program was also used to simulate a series of I-shaped subassemblages that were tested at the University of Sheffield. Comparisons were made between the analytical and experimental results characterized by the maximum loads, load-deflection curves and load- moment curves. Good agreement was obtained between the analytical and the experimental load-deflection curves for all of the cases considered. The general trends of the measured and calculated load- moment curves for most cases were found to be comparable. The recommendations given in B35950 for the design of columns in simple construction were applied to all cases in the last series and were found unconservative in the cases of balanced loading and conservative in the cases of unbalanced loads. A limited parametric study was conducted to study the effects of semi-rigid joints, bean flexibility and type of loading. In this study, an I-shaped subassemblage was analysed for different load types and different types of beam to column connections. A substantial effect was recognized due to the presence of semi-rigid connections whether or not a beam load was applied. Beam flexibility was also seen to affect the carrying capacity of the subassemblage under the action of column load only although this effect was less noticeable than that of the connection flexibility. The presence of beam load was found to result in an unexpected interaction curve which relates the total force in the column to the moment that is transmitted to the column's end. An almost linear relationship with negative gradient seems to exist between the column and beam loads. It is pointed out that all the findings of the present study are based on the range of cases considered in the parametric study but it is suggested that they serve as indicators to the behaviour of any the subassemblage under axial load oniy or axial load combined with beam loads. A few recommendations for future work are presented.

As estruturas tubulares, muitas vezes, têm sua aplicação restrita a construções onde a concepção arquitetônica determina o seu uso, no entanto há algumas vantagens do ponto de vista estrutural que podem justificar a sua aplicação. A reduzida área exposta ao fogo e aos ambientes agressivos, boa resistência a compressão axial com baixa tendência ao desenvolvimento de instabilidades localizadas, são algumas das vantagens da utilização destas estruturas. O objetivo principal deste trabalho é analisar numericamente o comportamento da ligação entre viga de seção I com coluna tubular circular, para tanto são consideradas configurações usuais de ligação com anéis externos transversais e chapa de alma. É ainda objetivo trazer um panorama das estruturas tubulares em geral, com o desenvolvimento histórico das pesquisas, e principalmente estabelecer uma compilação dos procedimentos analíticos de cálculo e classificação apresentados pelas normas Eurocode 3 e ANSI/AISC. A análise numérica foi realizada por meio dos pacotes comerciais TRUEGRID® e ANSYS®, os quais aplicam o método dos elementos finitos. Foram empregados modelos que consideram as características mecânicas do aço, como plastificação e encruamento, e ainda as não-linearidades geométricas e de contato. Os resultados numéricos apresentaram coerência razoável com os modelos analíticos normativos. Foi possível o conhecimento do comportamento M-\'fi\' (momento-rotação) das ligações, bem como a determinação dos parâmetros que caracterizam tal relação, como resistência, rigidez inicial e ductilidade. Os estudos comprovaram a eficácia dos anéis externos na distribuição dos esforços oriundos do engastamento parcial da viga, fazendo com que a coluna não seja comprometida. / The application of tubular structures is usually restricted to constructions on which the architectural conception demands them. However, there are also several structural advantages which justify their usage, such as a) reduced exposed area concerning fire and agressive environments; b) high axial compression resistance; c) high local buckling resistance. The aim of this work is the numerical analysis on the behavior of the I beam-circular hollow column connection, usually constituted by an external ring with single plate. It is presented a general view about the researchers development over the years on tubular structures focusing the compilation of the analytical design procedures and Eurocode 3 and ANSI/AISC classification as well. Finite element method softwares TRUEGRID and ANSYS are used for the numerical analysis in order to consider steel mechanical properties such as yielding, hardening and also geometric and contact nonlinearities. Numerical results present good agreement to codes\' analytical models. Analysis lead to understanding the connection\'s moment-rotation behavior and some of its parameters such as resistance, initial stiffness and ductility. It is shown external rings significantlly improve the semi-rigid connections stress distribution at the columns face.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15367号 / 工博第3246号 / 新制||工||1488(附属図書館) / 27845 / 京都大学大学院工学研究科建築学専攻 / (主査)教授 中島 正愛, 教授 林 康裕, 教授 吹田 啓一郎 / 学位規則第4条第1項該当

Yes / Elliptical Hollow Sections (EHSs) have been utilized in construction recently because of their visual appearance as well as the potential structural efficiency owing to the presence of the two principle axes. However, little information currently exists for the design of beam to elliptical column connections, which is an essential part of a building structure. Thus, to ensure the safe and economic application of EHSs, a new research project has been initiated. Rotation behaviour of simply bolted beam to concrete-filled elliptical steel column connections was investigated experimentally. Various joint types were considered and the benefits of adopting core concrete and stiffeners were highlighted. This paper covers the experimental studies and simulation of the connections using the ABAQUS standard solver. Comparisons of failure modes and moment vs. rotation relationships of the connections between numerical and experimental results were given. Good agreement has been obtained and the developed finite element model was therefore adopted to conduct a preliminary parametric study to explore the effect of critical parameters on the structural behaviour of beam to concrete-filled elliptical column connections.

Yes / This paper investigated the rotation behaviour of simply bolted I-beam to concrete-filled elliptical steel tubular (CFEST) column connections experimentally. Ten different joint assemblies were tested to failure, with a constant axial compressive load applied to the column and upwards concentrated loads at the beam ends. All of the steel tubes were hot-finished and had a cross-sectional aspect ratio of 2. The orientation of the column and the arrangement of the stiffening plates were taken into consideration. Moment versus rotation relationships and failure modes were compared for each joint, highlighting the benefits of using core concrete and stiffeners in these connections.

No description available.

Prior studies indicated that beam-to-column connections of reinforced concrete (RC) moment resisting frame structures experience considerable deformations under earthquake loading and these deformations have a major contribution to story drift of the building. In current analysis and design applications, however, the connection regions are generally modeled as rigid zones and the inelastic behavior of the joint is not taken into account. This assumption gives rise to an underestimation of the story drifts and hence to an improper assessment of the seismic performance of the structure. In order to implement the effect of these regions into the seismic design and analysis of buildings, a model that properly represents the seismic behavior of connection regions needs to be developed. In this study, a parametric model which predicts the joint shear strength versus strain relationship is generated by investigating the several prior experimental studies on RC beam-to-column connections subjected to cyclic loading and establishing an extensive database. Considering previous experimental research and employing statistical correlation method, parameters that significantly influence the joint behavior are determined and these parameters are combined together to form a joint model. This model is then verified by comparing the results obtained from the dynamic earthquake analysis by Perform 3D with the experimental ones. The main contribution of the developed model is taking into account parameters like the effect of eccentricity, column axial load, slab, wide beams and transverse beams on the seismic behavior of the connection region, besides the key parameters such as concrete compressive strength, reinforcement yield strength, joint width and joint transverse reinforcement ratio.

Submitted by Bruna Rodrigues (bruna92rodrigues@yahoo.com.br) on 2016-10-21T11:19:33Z No. of bitstreams: 1 DissRPT.pdf: 4811322 bytes, checksum: 5b9ef88d0970029bb522b0d047896637 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-11-08T18:45:00Z (GMT) No. of bitstreams: 1 DissRPT.pdf: 4811322 bytes, checksum: 5b9ef88d0970029bb522b0d047896637 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-11-08T18:45:06Z (GMT) No. of bitstreams: 1 DissRPT.pdf: 4811322 bytes, checksum: 5b9ef88d0970029bb522b0d047896637 (MD5) / Made available in DSpace on 2016-11-08T18:45:12Z (GMT). No. of bitstreams: 1 DissRPT.pdf: 4811322 bytes, checksum: 5b9ef88d0970029bb522b0d047896637 (MD5) Previous issue date: 2016-06-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / This work presents the development of a numerical model of a composite connection connecting a composite beam to a concrete filled steel tube column using a through plate. The software Ansys® and finite elements methods were used in the numerical analyses and the model was validated by comparison with experimental results. The main guidelines adopted in the choice of finite elements, material properties and constitutive relationships, boundary conditions and restrains and other aspects of numerical modeling are presented and discussed in this work. The validated numerical model was then used in parametric analysis in which was analyzed the influence of geometric and physical parameters as reinforcement ratio of slab, height of I-steel beam, web thickness of I-steel beam, diameter of the bolts, slab thickness, height of the through plate, concrete compressive strength and steel yield strength. The parameters analyzed revealed direct influence on behavior, especially in terms of moment an initial stiffness. Comparative analysis between all parameters allowed comments on the most influential variables and those that present similar behaviors. / Apresenta-se neste trabalho o desenvolvimento de um modelo numérico de ligação mista vigapilar preenchido com chapa passante. Para tanto, utilizou-se o método dos elementos finitos via pacote computacional Ansys®. O modelo numérico foi então validado com base em resultados encontrados na literatura. No presente estudo são apresentadas as principais diretrizes adotadas na escolha dos elementos finitos, propriedades dos materiais e relações constitutivas, condições de contorno e vinculações, carregamentos e outros aspectos referentes à modelagem numérica. O modelo numérico validado foi então utilizado na realização de análises paramétricas nas quais foi analisada a influência de parâmetros geométricos e físicos, como taxa de armadura da laje, altura dos perfis de aço da viga mista, espessura da alma do perfil da viga mista, diâmetro dos parafusos, altura da laje, altura da chapa passante, resistência do concreto e resistência ao escoamento do aço. Os parâmetros analisados revelaram influência direta no comportamento da ligação, principalmente em termos de momento resistente e rigidez inicial. Análises comparativas entre todos os parâmetros permitiram observações sobre as variáveis mais influentes e aquelas que apresentam comportamentos semelhantes.

Prior experimental research clearly reveals that the performance of reinforced concrete frame structures under earthquake loading is closely related to the behavior of beam-to-column connection regions. In order for a reinforced concrete building to have an adequate response under high lateral deformations, beam-to-column connections should be able to preserve their integrity. However, even today beam-to-column connections are assumed to be rigid or elastic, leading to an incorrect estimation of the structural response under earthquake loading. One of the basic reasons for the assumption of rigid joints is the lack of analytical models that adequately represent the seismic behavior of the connection region. In this thesis, an analytical model that realistically represents the beam-to-column connection response is developed, in the light of prior experimental data. The experimental subassemblies used in the generation of the analytical model are later modeled in OpenSees environment in order to verify the accuracy of the model. Throughout the research, utmost attention is paid for the model to be simple enough to be used practically and also to cover a wide range of beam to column connection properties.