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1
Unal, Mehmet. "Analytical Modeling Of Reinforced Concrete Beam-to-column Connections." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612230/index.pdf.
Повний текст джерелаАнотація:
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.
2
Mazzarolo, Enrico. "Analysis and Development of an Innovative Prefabricated Beam-to-Column Joint." Doctoral thesis, Università degli studi di Trento, 2012. https://hdl.handle.net/11572/367656.
Повний текст джерелаАнотація:
The use of pre-fabricated concrete components and their related coupling systems in seismic engineering constitutes a subject of wide and deep interest among researchers, practitioners and manufacturers all over the world, as demonstrated by a large number of studies conducted, among other Countries, especially in Japan, New Zealand and United States since the early ‘80s and, in relatively more recent times, in Italy. A key issue is given by the possibility to apply the typical benefits of the pre-fabrication not only to low rise industrial/commercial structures, but also to multi-storey frames for public and strategic buildings such as schools, hospitals and many others, as well as to high-rise residential premises built in areas characterized by a medium to high seismic intensity. On the basis of what stated above, an original structural system made by prefabricated composite steel truss-concrete beams and centrifuged high-strength concrete columns is presented in the following. Specifically designed joints are provided to couple the different structural components in order to guarantee an overall ease of construction with reduced tolerance problems and self-bearing capacity during temporary erection phases, with a consequent reduction in schedule and costs. The use of high performance concrete for columns allows for a high bearing capacity with limited overall dimensions and the consequent maximization of the commercial or saleable space. The original layout of the system proposed has led to the need to perform an intensive theoretical and experimental research activity. The finite element model of the structural system was calibrated upon both static and cyclic testing evidence carried out on full scale samples built in Italy and tested at the Tongji University-Shanghai, China. On the basis of the data collected, the tuned model was used to carry out further analyses and to deepen the specific knowledge on several further aspects, as specified in the following. Firstly, an estimation of the joint’s strength domain, suitable for everyday’s design was carried out based on a component-approach. Then, a structural optimization on the component used to guarantee hogging and sagging bending moment resistance to the joint, was carried out in order to achieve the minimization of the construction material employed. Furthermore, the estimation of the seismic performance of the joint, based on the evaluation of a purposely defined vulnerability parameter, supplied encouraging results with reference to the applicability of the investigated technology over most of the National territory. Finally an improved layout of the joint, with reference to confined concrete and the related possibility to achieve a suitable seismic response also at edge joints, is presented.
3
Yang, Jie. "Structural behaviour of concrete-filled elliptical column to I-beam connections." Thesis, University of Bradford, 2017. http://hdl.handle.net/10454/16022.
Повний текст джерелаАнотація:
Concrete-filled tubular (CFT) columns have been widely adopted in building structures owing to their superior structural performance, such as enhanced load bearing capacity, compared to hollow tubes. Circular, square and rectangular hollow sections are most commonly used in the past few decades. Elliptical hollow section (EHS) available recently is regarded as a new cross-section for the CFT columns due to its attractive appearance, optional orientation either on major axis or minor axis and improved structural efficiency. The state of the research in terms of elliptical columns, tubular joints between EHSs and connections with CFT columns, etc., are reviewed in this thesis, showing a lack of investigations on EHSs, especially on beam to elliptical column connections which are essential in framed structures. The structural behaviour of elliptical column to I-beam connections under bending is studied in this thesis to fill the research gap. Overall ten specimens with various joint assemblies were tested to failure to highlight the benefits of adopting concrete infill and stiffeners in the columns. A three-dimensional finite element model developed by using ABAQUS software is presented and verified against obtained experimental results, which shows acceptable accuracy and reliability in predicting failure modes of the connections and their moment capacities. Parametric studies were performed to access the main parameters that affecting the bending behaviour of the connections. A simple hand calculation method in terms of ultimate moment capacity is proposed according to experiments conducted for connections with concrete-filled columns.
4
SILVA, RAQUEL ALVES CABRAL. "THEORETICAL AND EXPERIMENTAL ANALYSIS OF A COMPOSITE SEMI-RIGID BEAM-TO-COLUMN JOINT USING PERFOBOND SHEAR CONNECTORS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=27553@1.
Повний текст джерелаАнотація:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Nos projetos de engenharia é comum desconsiderar-se o comportamento semirrígido das ligações, ou seja, as ligações são assumidas com as condições ideais de rigidez. A primeira condição ideal é aquela na qual há transferência total de momento fletor, assumindo-se que não existe rotação relativa entre os elementos ligados, estas ligações são as chamadas rígidas. Na segunda opção, a transferência de momento fletor é desconsiderada e a ligação é definida como rotulada ou simples. Entretanto, sabe-se que a maioria das ligações comporta-se como semirrígida e o problema é que ao se fazer essas simplificações em projeto, dois aspectos podem ser comprometidos: segurança estrutural e custo do projeto. Neste trabalho, uma ligação semirrígida mista é proposta e estudada com o objetivo de obter-se as suas características principais e necessárias para utilizá-la em projeto: curva momento-rotação, rigidez de serviço e momento fletor resistente. Com a ligação mista proposta, busca-se uma nova maneira de transferência de forças na região de momento negativo em uma viga semicontínua. Adotou-se para a transferência dos esforços, entre a laje de concreto e a viga de aço, conectores de cisalhamento do tipo Perfobond Rib. Este conector foi inicialmente utilizado em pontes e depois alguns estudos o viabilizaram para o uso em edificações. Para atingir os objetivos do trabalho, foram realizados dois ensaios em escala real das ligações propostas. Os testes experimentais foram feitos em modelos cruciformes invertidos e realizados no laboratório de estruturas e materiais da PUC-Rio. Os resultados experimentais foram comparados com dois modelos analíticos: o método proposto por Leon et al. em 1996 e o método presente no Anexo R da NBR 8800:2008.
In engineering design it is common to disregard the semi-rigid behavior of connections, i.e., connections are assumed to have the ideal conditions of rigidity. The first ideal condition is the one in which there is full transfer of bending moment, assuming that there is no relative rotation between the connected elements, this connection is defined rigid. In the second option, the transfer of bending moment is disregarded and the connection is defined simple. However, it is known that most connections have a semi-rigid behavior and the problem is that when making these simplifications in design, two aspects can be compromised: structural safety and project cost. In this work, a composite semi-rigid connection is studied in order to obtain its main and necessary features to use it in design: moment-rotation curve, service rigidity and bending moment capacity. With the proposed composite connection, a new way to transfer forces in the negative moment region on a semicontinous beam. Shear connectors like the Perfobond Rib were adopted for the transfer of efforts between the concrete slab and the steel beam. This connector was first used on bridges and since then some studies have made possible its use in buildings, showing its advantages over the more usual connectors. To achieve this work s objectives, two real scale tests of the proposed connections were conducted. Experimental tests were done in inverted cruciform models and carried out in the laboratory of structures and materials at PUC-Rio. Information on these tests was obtained, such as displacements, strains, and cracking of the slab. The experimental results were compared to two analytical models: the method proposed by Leon et al. in 1996 and the present method in Annex R of NBR 8800: 2008.
5
Dissanayake, Udaya Indrajith. "The influence of the composite beam-to-steel column joint on the behaviour of composite beams in frames." Thesis, University of Sheffield, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389752.
Повний текст джерела
6
[Verfasser], Saenboon Amorntipsakul. "Generic Finite Element Model for Mechanically Consistent Scaling of Composite Beam-to-column Joint with Welded Connection / Saenboon Amorntipsakul." Kassel : Universitätsbibliothek Kassel, 2013. http://d-nb.info/1041369263/34.
Повний текст джерела
7
Motamed, Jubin. "Monolithic beam to external column joints in reinforced concrete." Thesis, University of Westminster, 2010. https://westminsterresearch.westminster.ac.uk/item/90727/monolithic-beam-to-external-column-joints-in-reinforced-concrete.
Повний текст джерелаАнотація:
The benefits of high strength concrete (HSC) in the construction of multi-storey buildings are commonly acknowledged. Past researchers have investigated the suitability of design codes for the use of HSC [1]. However, there are concerns about the shear behaviour of HSC beams and BCJ used in the construction of these buildings. HSC beams have equal or less shear resistance compared to normal strength concrete (NSC) beams [2], and the brittleness of HSC material could be unsuitable for BCJ as confinement stirrups may not be as effective as NSC in the column due to a smaller Poisson’s ratio. This research investigates the behaviour of HSC beams, BCJ and transfer beam column joints (TBCJ), and develop appropriate design modifications to improve their shear capacity. HSC beams were strengthened with horizontal web bars (HWB), while TBCJ were strengthened with central vertical bars (CVB). Finite element (FE) models were developed for these structures and the numerical results were compared with those of the published experimental results, concluding that good agreement had been achieved. Beam span/depth (a/d) ratio of 1.5≤a/d ≤3.02 and BCJ of beam to column depth ( db/dc ) ratio of 1.33 ≤ db/dc ≤3.1 were analysed. The FE models were compared with published test results and further ones were developed to carry out various parametric investigations. Struts and ties were mechanically modelled for beams with HWB and for TBCJ with CVB are used to recommend design equation modifications for the design of HSC beams with HWB and TBCJ with CVB. It was found that HWB and CVB are effective in beams and BCJ only with HSC as they have little influence when they were used with NSC. Using HWB in HSC beams and CVB in HSC TBCJ improved the shear capacity of these structures by 130% and 31% respectively. 1 - Regan, P. E., Kennedy -Reid I. L., Pullen, A. D., Smith, D. A. ‘The influence of aggregate type on the shear resistance of reinforced concrete’ – The Structural Engineer. 6 December 2005. p 27-32. 2 - Al-Hussaini, A. Motamed, J. ‘HSC beams with combination of links and horizontal web steel as alternative shear reinforcement’. 6th International Symposium on Utilization of High Strength/High Performance Concrete, Leipzig, June 2002. p 611- 619
8
Rifai, Abdussalam Mahmud. "Behaviour of columns in sub-frames with semi-rigid joints." Thesis, University of Sheffield, 1987. http://etheses.whiterose.ac.uk/3050/.
Повний текст джерелаАнотація:
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.
9
Bernardi, Martina. "Industrial steel storage racks subjected to static and seismic actions: an experimental and numerical study." Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/322402.
Повний текст джерелаАнотація:
Industrial steel storage racks are pre-engineered lightweight structures commonly used to store goods from supermarkets to big warehouses. These systems are framed structures, usually made of cold-formed steel profiles and characterised by non-standard details. Their performance is quite complex and the prediction of their global response is more difficult than for the traditional steel frames. This difficulty is due to the racks’ main features: the use of cold-formed thin-walled steel sections which are sensitive to different buckling modes, the presence of regular perforation patterns on the uprights, the highly non-linear behaviour of joints, the influence of the structural imperfections and the significant frame sensitivity to second order effects. The behaviour of racks becomes even more complex when seismic or accidental events induce significant horizontal forces acting on the structures. The complexity and variability that characterise racks make it difficult to identify general design solutions. Hence, racks design is traditionally carried out by using the “design by testing” approach, which requires the experimental characterisation of the main structural components, of the joints and the sub-assemblies. The complexity of the racks also affects their numerical modelling, which results in complex analyses that must take into account all the aforementioned features. The work presented in this thesis focuses on the study of a typical steel pallet rack, identified as case study. The research aims to contribute to building up a comprehensive knowledge of the response of both the main rack components and of the whole structure. The main rack components were first individually studied. The behaviour of the uprights, of the base-plate joints and of the beam-to-column joints was experimentally investigated. The experimental data were then taken as reference for the calibration of FE models that enabled exploring each component’s performance. These models were then incorporated into the whole rack model. The response of the uprights was first investigated through stub column tests. The non-negligible interaction between axial force and bending moment of the upright response was then experimentally and numerically analysed to define the M-N domains. In addition, the rules provided by different European standards for the design of isolated members subjected to combined axial load and bending moment were considered and critically compared, identifying the main critical issues of the different design approaches. Although the contribution of joints on the rack global response is of paramount importance, to date, the knowledge is quite limited. In particular, the experimental studies of the behaviour of base-plate joints are still rather modest, especially for the cyclic range. Therefore, an experimental campaign on the rack base-plate joints was carried out: three levels of axial load were considered and the response in both the down-aisle and the cross-aisle direction was investigated under monotonic and cyclic loadings. Similarly, the beam-to-column joint was tested both monotonically and cyclically, taking into account its non-symmetric behaviour. Numerical models for both joint types were developed and validated enabling the characterisation of joints in the monotonic and cyclic range. This in-depth knowledge of the response of individual components facilitated the evaluation of the global rack behaviour. As a final stage of the research, full-scale tests of four-level two-bay racks were performed taking advantage of an innovative full-scale testing set-up and, on the basis of the experimental outcomes, the racks’ global behaviour was numerically investigated. Critical standards issues and needs for future research were further identified.
10
Leong, Mun-Foo. "MOMENT-ROTATION CHARACTERISTICS OF BEAM-TO-COLUMN CONNECTIONS." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275028.
Повний текст джерела
11
Elflah, Mohamed A. Hussaen. "Structural behaviour of stainless steel bolted beam to column joints." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8545/.
Повний текст джерелаАнотація:
Initially, two experimental programmes studying the structural behaviour of stainless steel beam-to-open column joints and beam-to-tubular column joints under static loads are reported in detail. The joint configurations tested include flush and extended end plate connections, top and seat cleat connections and top, seat and web cleat connections. The full moment-rotation characteristics are reported in detail. It is observed that the connections displayed excellent ductility, superior than that of equivalent carbon steel connections, and attained loads much higher than the ones predicted by design standards for carbon steel joints. Nonlinear FE models have been developed and validated against the experimental results. The FE models are shown to accurately replicate the experimentally determined, initial stiffness, ultimate resistance, overall moment-rotation response and observed failure modes. In addition, a comprehensive parametric study is conducted. The design rules for stainless steel connections, which are based on the specifications of EN 1993-1-8 for carbon steel joints, are reviewed and are found to be overly conservative in terms of strength and inaccurate in terms of stiffness thus necessitating the development of novel design guidance in line with the observed structural response. Hence, simplified mechanical models in line with the observed response are developed.
12
Islam, Mohammad Aminul. "Constitutive modeling and plastic analysis with application to beam-to-column connections." Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184486.
Повний текст джерелаАнотація:
Analysis and design of connections, such as beam-to-column connections, pose various complexities such as nonlinear behavior of material and geometric condition, irregularities in geometry and boundary condition. The main purpose of these types of connections is to provide adequate structural strength and a sufficiently stiff structure at working loads, and to possess sufficient ductility and strength at overloads such as may occur during a major earthquake. At present the design profession does not have established guidelines for estimating the ultimate moment and shear capacity of these connections. The assumption of linear elastic material behavior of the connections is no longer valid when the elements are stressed beyond the yield stress of the material. For such problems encountered in the design of typical structures, either the closed-form analytical solutions are extremely complex or cannot be obtained at all. Thus, numerical techniques such as finite difference, finite element and boundary integral methods are used. In this study, a finite element program is developed for plastic analysis of connections such as beam-to-column connection using a constitutive law of the material, a three parameter stress-strain relationship, which gives stress explicitly in terms of strain. One hundred and fifteen cases of beam-to-column connections subjected to moment are analysed with the finite element program developed in this study, and the results are compared with the existing approximate solution by yield line theory to propose a simple formula to correlate actual ultimate capacity to the approximate solution.
13
Smallidge, Jeffrey M. "Behavior of bolted beam-to-column T-stub connections under cyclic loading." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/19534.
Повний текст джерела
14
Jiménez, Torres Adrià. "Seismic design of steel beam-to-column joints with reduced beam section using European hotrolled." Doctoral thesis, Universitat Politècnica de Catalunya, 2021. http://hdl.handle.net/10803/673353.
Повний текст джерелаАнотація:
The design rules on Reduced Beam Sections (RBS) are covered in the Eurocodes in EN1998-3 as a possible solution to improve rotation capacity of beams for the retrofit of existing structures. The design rules are very similar to those in AISC358
provisions, although European cross-sections and steel grades are different. Research pieces on RBS in a European environment are few and do not study this matter with an extensive parametric study to assess their behaviour. Moreover, the
design rules in EN1998-3 only show how to design the weakened section of the beam, but they do not provide any additional information on whether further action is needed on the structure for the design of other members such as braces or if special considerations need to be made for connection detailing. The current state of the Eurocodes does not consider the design of
a new structure with RBS, while AISC358 provisions do allow for new RBS designs.
The aim of this PhD thesis is to study the behaviour of the RBS and find the most relevant design parameters affecting its response in a beam-to-column assembly level and to study the benefits of incorporating RBS as a solution for the design of
new structures in seismic areas. In order to fulfill the first goal, a numerical model has been developed in Abaqus in order to assess the behaviour of RBS and to discuss the results obtained from them. Hot-rolled European sections have been studied from the HEA and IPE cross-section families, as well as a built-up slender girder and an American Jumbo section.
Several different cutouts (or trimmed flange widths) are investigated, as well as S235 and S355 steel grades with their cyclic hardening properties. The influence on the column web panel strength is also considered in the parametric study. The
results obtained are then examined to compare degradation ratios, overstrength ratios, lateral-torsional buckling development, dissipated plastic work and plastic damage by means of equivalent plastic strains (PEEQ).
In order to fulfill the second goal, two different studies have been performed to assess the influence of the RBS in a structure subjected to seismic load. The behaviour of a structure provided with RBS is compared to that of a control structure without RBS. The results have been obtained and the differences found have been quantified in order to objectively report the benefits found when adopting RBS
After having studied the behaviour of the RBS both locally (at a beam-to-column level) and globally, the main conclusions have been derived. Also, design recommendations to take into consideration for the design of new RBS are provided in order
to ensure a proper behaviour of the RBS when subjected to seismic loads and to guarantee overall good structural behaviour.Les regles de disseny de les bigues de secció reduïda (RBS) es cobreixen als eurocodis en la norma EN1998-3 com a possible solució per millorar la capacitat de rotació de bigues per a la rehabilitació de les estructures existents. Les normes de disseny són molt similars a les de les disposicions de l'AISC358, tot i que les seccions transversals europees i els graus d'acer són diferents. Les investigacions sobre RBS en un entorn europeu són poques i no estudien aquest tema amb un ampli estudi paramètric per avaluar el seu comportament. A més, les regles de disseny de la norma EN1998-3 només mostren com dissenyar la secció reduïda de la biga, però no proporcionen informació addicional sobre si cal fer més accions a l'estructura per al disseny d'altres elements o si calen altres consideracions especials en el detallat de la connexió. L'estat actual dels eurocodis no contempla el disseny d'una nova estructura amb RBS, mentre que les disposicions AISC358 permeten nous dissenys de RBS. L'objectiu d'aquesta tesi doctoral és estudiar el comportament de les RBS i trobar els paràmetres de disseny més rellevants que afecten la seva resposta a nivell local de biga a columna i estudiar els avantatges d'incorporar RBS com a solució per al disseny de noves estructures en zones sísmiques. Per complir el primer objectiu, s'ha desenvolupat un model numèric amb Abaqus per avaluar el comportament de RBS i discutir els resultats obtinguts d'ells. S'han estudiat seccions europees laminades en calent pertanyents a les famílies de seccions transversals HEA i IPE, així com una biga esvelta armada i una secció Jumbo americana. S'investiguen divers os retalls (o amplades d'ales de biga retallades), així com els graus d’acer S235 i S355 amb les seves propietats d'enduriment cíclic. La influència de la resistència relativa de la zona de l'anima de la columna també es considera en l’estudi paramètric. A continuació, s'examinen els resultats obtinguts per comparar les ràtios de degradació, les ratios de sobrerresistència, el desenvolupament de vinclament lateral-torsional, l'energia dissipada per deformació plàstica i el dany plàstic mitjançant deformacions plàstiques equivalents (PEEQ). Per tal de complir el segon objectiu, s'han dut a terme dos estudis diferents per avaluar la influència de la RBS en una estructura sotmesa a càrrega sísmica. El comportament d'una estructura proveïda de RBS es compara amb el d'una estructura de control sense RBS. S'han obtingut els resultats i s'han quantificat les diferències trobades per tal d'informar objectivament dels beneficis trobats en adoptar RBS. Després d'haver estudiat el comportament de la RBS tant a nivell local (a nivell de biga a columna) com a nivell global, s'han extret les principals conclusions. A més, es proporcionen recomanacions de disseny a tenir en compte per al disseny de nous RBS per tal de garantir un comportament correcte de l'RBS quan està sotmès a càrregues sísmiques i per garantir un bon comportament estructural en general.
Enginyeria de la construcció
15
Tristão, Gustavo Alves. "Análise teórica e experimental de ligações viga mista-pilar de extremidade com cantoneiras de assento e alma." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-28092006-101125/.
Повний текст джерелаАнотація:
Este trabalho apresenta um estudo numérico e experimental do comportamento estrutural das ligações viga mista-pilar com cantoneiras de assento e alma. No estudo teórico foi desenvolvido, com base nos EUROCODES 3 e 4, um procedimento para avaliação do comportamento das ligações mistas com cantoneiras de alma e assento e com chapa de topo. O trabalho de investigação experimental, abrangendo modelos submetidos a carregamentos monotônico e cíclico, foi realizado no Instituto Superior Técnico (IST), Portugal, em que o objetivo principal foi avaliar a influência da força axial de compressão no pilar para o comportamento do painel da alma do pilar, e conseqüentemente no comportamento global da ligação mista localizada em nó de extremidade. Nos ensaios experimentais foram analisadas as rotações e deformações no painel da alma do pilar sem e com enrijecedor na alma do pilar. Adicionalmente, a eficiência da ancoragem das barras de armadura longitudinal foi verificada. Paralelamente à investigação experimental, um estudo numérico de ligações mistas foi realizado por meio do modelo em elementos finitos, o qual mostrou-se representativo, tornando-se uma ferramenta para análises paramétricas.This work presents a numerical and experimental study of the structural behavior of beam-to-column composite joints with bottom and web angle connections. In the theoretical study, basing in EUROCODES 3 and 4, an analytic procedure for evaluation the static behavior of beam-to-column composite joints with bottom and web angle connections was developed. The experimental test program, enclosing monotonic tests and a cyclic test, was carried out at the Instituto Superior Técnico of Lisbon (IST), where the main objective was to evaluate the effect of column axial load on column web panel and consequently in the global behavior of single-sided composite joint. In the tests, the panel zone rotations and deformations were analyzed for stiffened and unstiffened column web. In addition, the efficiency of the main rebar was verified. Finally, a thorough of finite element model, a numerical study of composite joints was developed. This model was found to be representative and reliable as a tool to futures parametric analyses.
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Lima, Carmine. "Capacity models for beam-to-column joints in RC frames under seismic actions." Doctoral thesis, Universita degli studi di Salerno, 2011. http://hdl.handle.net/10556/155.
Повний текст джерелаАнотація:
2009 - 2010Le strutture in cemento armato realizzate intorno aglia anni '60 e '70 rappresentano, ad oggi, la maggior parte del patrimonio edilizio esistente in Italia. Inoltre, esse sono spesso strutture strategiche ai fini della gestione delle emergenze in quanto ospitano scuole ed ospedali. Tali edifici, nonostante l'importanza strategica, risultano nella maggioranza dei casi vulnerabili rispetto agli eventi sismici a causa dell'insufficente capacità in termini di resistenza e duttilità, generalmente dovuti all'eccessivo passo delle staffe dei pilastri e all'assenza di rinforzo trsversale nei nodi trave-colonna. Alla luce dei danni osservati nel corso dei recenti eventi sismici di Assisi (1996), Molise (2002) e L'Aquila (2009)gli studi sulla vulnerabilità sismica delle strutture sono stati intensificati nell'ultimo ventennio. I report che descrivono i danni osservati sulle strutture esistenti mettono in risalto il ruolo chiave dei nodi trave-colonna sul comportamento globale delle strutture in cemento armato. Numerose formulazione teoriche ed analitiche sono state proposte nel corso degli anni per valutare la resistenza a taglio di tali ecomponenti strutturali. La presente tesi raccoglie le formulazioni attualmente disponibili in letteratura e nelle principali normative antisismiche per stimare la resistenza a taglio dei nodi esterni ed interni.
IX n.s.
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Bousri, Yahia. "Experimental and analytical study of reinforced concrete external beam-column subjected to cyclic loading." Thesis, University of Bristol, 1994. http://hdl.handle.net/1983/692583ab-1cce-4e31-9250-b1c322c8caef.
Повний текст джерела
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Spyrou, Spyros. "Development of a component based model of steel beam-to-column joints at elevated temperatures." Thesis, University of Sheffield, 2002. http://etheses.whiterose.ac.uk/12830/.
Повний текст джерелаАнотація:
The response of steel-framed structures to applied loading depends to a large degree on the behaviour of the joints between the columns and beams. Traditionally designers have assumed that these joints act either as 'pinned', with no ability to transmit moments from beam to column, or as 'rigid', providing perfect continuity between the connected members. Advances in analysis, and developments in modem codes of practice, permit designers to account for the real behaviour of steel joints where this is known or can be predicted. Even though experimental studies of joints conducted at many research centres around the world have provided a large bank of test data, the vast number of variables in joints (beam and column sizes, plate thicknesses, bolt sizes and spacing, etc.) often means that data for a specific joint arrangement does not exist. As a result, researchers have turned their attention to ways of predicting the behaviour of such joints. One approach which has gained acceptance is based on the "Component Method" in which overall joint behaviour is assumed to be produced by the responses of its various simpler components. To date, data on the response of joints at elevated temperatures has been gathered from full-scale furnace tests on cruciform arrangements, which have concentrated exclusively on moment-rotation behaviour in the absence of axial thrusts. However, when steel-framed structures are subjected to fire, the behaviour of the joints within the overall frame response is greatly affected by the high axial forces which are created by restraint to the thermal expansion of unprotected beams. If momentrotation- thrust surfaces were to be generated this process would require prohibitive numbers of complex and expensive furnace tests for each joint configuration. The alternative, and more practical, method is to extend the Component Method to the elevated-temperature situation. The basic theme of the Component Method is to consider any joint as an assembly of individual simple components. Each of these components is simply a non-linear spring, possessing its own level of strength and stiffness in tension, compression or shear, and these will degrade as its temperature rises. The main objective of this study was to investigate experimentally and analytically the behaviour of tension and compression zones of end-plate connections at elevated temperatures. A series of experiments has been carried out and a simplified analytical model has been developed, and this has been validated against the tests and against detailed finite element simulations. The simplified model is shown to be very reliable for this very common type of joint, although similar methods will need to be developed for other configurations. The principles of the Component Method can be used directly in either simplified or finite element modelling, without attempting to predict of the overall joint behaviour in fire, to enable semi-rigid behaviour to be taken into account in the analytical fire engineering design of steel-framed and composite buildings.
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Schrauben, Corey S. "Behavior of full-scale bolted beam-to-column T-stub and clip angle connections under cyclic loading." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/20013.
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Jadid, Mansour Nasser. "The application of neural network techniques to the analysis of reinforced concrete beam-column joints subjected to axial load and bi-axial bending." Thesis, University of Edinburgh, 1994. http://hdl.handle.net/1842/14160.
Повний текст джерелаАнотація:
The application of neural networks in the form of parameter predictions to the behaviour and strength of beam-column joints under axial load and biaxial bending has been studied. Computation algorithms in the form of numerical analysis were performed on the beam-column joints to simulate the existing experimental data. A systematic approach was provided by implementing neural networks in the form of prediction by backpropagation algorithms. The objective of this study was to demonstrate a concept and methodology, rather than to build a full-scale knowledge-based system model, by incorporating most of the fundamental aspects of a neural network to solve the complex non-linear mapping of a beam-column joint. In general, it should be possible to identify certain parameters and allow the neural network to develop the model, thus accounting for the observed behaviour without relying on a particular algorithm but depending entirely on the manipulation of numerical data. The aim of this study was to view available experimental data on beam-column joint parameters from different angles and establish a concept and methodology that would provide rapid and economic benefits to experimental research. The focus of this study is to reconstruct previous experimental work by evaluating several parameters and establish valid mathematical relationships based on neural networks which are in agreement with relationships based on the experimental results. The computational methodology considered for the analysis of the beam-column joints has been formulated by adopting three stages to establish a procedure to implement the concept and methodology proposed. The procedure is demonstrated by the evaluation of the ultimate flexural strength of the reinforced concrete members, the moment-curvature relationship and the shear strength of the beam-column joint.
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Lopes, Fernanda da Rocha de Carvalho. "Influência do comportamento semi-rígido de placas de base e de ligações viga-coluna na resposta dinâmica de pórticos de aço." Universidade do Estado do Rio de Janeiro, 2008. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=5646.
Повний текст джерелаАнотація:
Tradicionalmente, na análise e dimensionamento de estruturas de aço, assume-se que as ligações viga-coluna são rígidas ou flexíveis (rotuladas). Por outro lado, é de conhecimento geral que a grande maioria das ligações viga-coluna apresenta um comportamento intermediário, ou seja, semi-rígido. Inúmeros trabalhos de pesquisa têm sido desenvolvidos nos últimos vinte e cinco anos, de forma a estudar o comportamento desse tipo de ligação. Um dos principais objetivos desta investigação é o de propor uma metodologia de análise que represente de forma apropriada a influência do comportamento semi-rígido de placas de base e de ligações viga-coluna, sobre a resposta dinâmica (linear e não-linear) de estruturas de aço. Outra contribuição desta dissertação diz respeito à investigação do comportamento dinâmico (linear e não-linear) de pórticos de aço, a partir da consideração de ligações viga-coluna simétricas e não-simétricas e especialmente das placas de base. A análise estrutural é desenvolvida com base no emprego do programa de elementos finitos ANSYS [27]. Nos modelos em elementos finitos foram considerados os efeitos de não-linearidade geométrica (efeitos de segunda ordem), o comportamento não-linear das placas de base e das ligações viga-coluna e, bem como, o efeito de histerese que ocorre quando a estrutura é submetida a cargas cíclicas. Os resultados alcançados indicaram que o fenômeno físico da ressonância não ocorre no que se refere à resposta dinâmica dos modelos semi-rígidos não-lineares. A ressonância não ocorre na resposta dos modelos devido ao fato de que, na análise dinâmica não-linear, o efeito de histerese presente nas ligações (placas de base e viga-coluna), essencialmente com comportamento não-linear, provoca um amortecimento na resposta dinâmica da estrutura.Traditionally, the steel portal frame design assumes that beam-to-column connections are rigid or pinned. Despite these facts, it is largely recognized that the great majority of joints does not exhibit such idealized behaviour. These connections are called semi-rigid, and their design should be performed according to their actual structural behaviour. Extensive research has been performed over the past twenty-five years to estimate the actual behaviour of such joints. One of the main objectives of this work is to propose an analysis methodology to properly represent the influence of the semi-rigid behaviour of base plates and beam-to-column joints on the dynamical response of steel structures (linear and non-linear). Another important investigated issue concerned the assessment of the steel frames dynamical behaviour (linear and non-linear) due to the presence of symmetrical and non-symmetrical beam-to-column semi-rigid joints and, especially, the column base plates. The structural analysis was made with the aid of the ANSYS [27] finite element program. The finite element model included geometric non-linearity, column base plates and beam-to-column non-linear behaviour and considered the influence of non-linear and hysteretic moment versus rotation curve of the joints. The results indicated that the resonance physical phenomenon was not reached in the nonlinear semi-rigid frames dynamic response. The resonance did not occurred in these systems due to the hysteretic damping induced by the energy dissipation of the non-linear hysteretic loops at the non-linear joints.
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Rodrigues, Monique Cordeiro. "Modelagem numérica de ligações viga-coluna em aço sob momento fletor e força normal." Universidade do Estado do Rio de Janeiro, 2009. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=5636.
Повний текст джерелаАнотація:
Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorAs ligações desempenham um papel fundamental no comportamento global das estruturas de aço. Inúmeros trabalhos de pesquisa têm sido desenvolvidos para entender o comportamento real de uma ligação e sua influência na resistência global dos pórticos. Atualmente, a Norma Brasileira de estruturas de aço de edificações, NBR 8800, considera o comportamento das ligações entre duas situações extremas: rígidas, onde não ocorre nenhuma rotação entre os membros conectados, transferindo momento fletor, força cortante e força normal; ou flexíveis, caracterizadas pela liberdade de rotação entre os membros conectados, impedindo a transmissão de momento fletor. Outras normas de projeto de estruturas de aço, consideram que as ligações apresentam um comportamento intermediário, ou seja, semi-rigídas, que podem estar submetidas a uma combinação de momento fletor e esforço normal. Porém, mesmo com a combinação, estas normas não consideram a presença de esforço normal (tração e/ou compressão). Uma limitação empírica de 5% da resistência plástica da viga é a única condição imposta no Eurocode 3. Para o estudo da ligação semi-rigída será utilizada a filosofia do Método das Componentes, que verifica a resistência da ligação e sua classificação quanto à rigidez rotacional, desenvolvida através de modelos mecânicos (modelos de molas). O objetivo deste trabalho é descrever alguns resultados de caracterização de ligações viga-coluna com placa de extremidade ajustada à altura da viga obtidos através de um modelo de elementos finitos. Para tal, será realizada uma análise não-linear geométrica e de material. Esta análise possibilitará avaliar os principais parâmetros que influenciam no comportamento deste componente no que diz respeito a sua avaliação em termos de distribuição de tensões e deformações no modelo de forma global.
The joints develop a fundamental role in the global behaviour of steel structures. Several researches are being developed to understand the real behaviour of a joint and its influence in the global frame capacity and beam-to-column joints of the steels buildings. Nowadays, the Brazilian Code of the Steel Portal Frame Design, NBR 8800, considers the joint behaviour between two extreme situations: rigid, where any rotations dont occur between the connected members, transfering substantial bending moments, and also shear and axial forces; or pinned, its characterised by almost free rotation movement between the connected elements that prevents the transmission of bending moments. However, some actual codes of the steel structures project, consider that the joints present an intermediate behaviour, in other words, semi-rigid, that may be subjected to a combination of bending moment and axial force. But, these codes dont consider the presence of axial force (tension and/ or compression). A single empirical limitation of 5% of the beams plastic axial capacity is the only enforced provision in Eurocode 3. This filosofy design is based on components method, for joint capacity evaluation and its classification concerning the joint rotation stiffness. This component method is based on mechanical models (spring model) created by an association of rigids and flexible joints components represented by a translacional spring. The objective of this present work is describing some results of flush endplate semi-rigids beam-to-column joints obtained across finite elements method and geometric and material non-linear analises. These consider the main parameters that influence the components behaviour about the stress and deformation distribution.
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Nunes, Pedro Carlos da Lomba. "Análise Paramétrica de Ligações com Placa de Extremidade em Estruturas de Aço Submetidas a Momento Fletor e Força Axial." Universidade do Estado do Rio de Janeiro, 2006. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=424.
Повний текст джерелаАнотація:
Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de JaneiroUsualmente, o projeto de pórticos em estruturas de aço assume que as ligações viga-coluna são rígidas ou flexíveis. As ligações rígidas, onde não ocorre nenhuma rotação entre os membros conectados, transferem não só momento fletor, mas também força cortante e força normal. Por outro lado, as ligações flexíveis são caracterizadas pela liberdade de rotação entre os membros conectados impedindo a transmissão de momento fletor. Sabe-se que a grande maioria das ligações não possuem este comportamento idealizado. Na realidade, a maioria das ligações transfere algum momento fletor com um nível de rotação associado. Estas ligações são denominadas semi-rígidas e seu dimensionamento deve ser executado de acordo com este comportamento estrutural. Contudo, algumas ligações viga-coluna estão sujeitas a uma combinação de momento fletor (M) e força axial (N). O nível de esforço normal pode ser significativo, principalmente em ligações de pórticos metálicos com vigas inclinadas, em pórticos não- contraventados ou em pórticos com pavimentos incompletos. As normas atuais de dimensionamento de ligações estruturais em aço não consideram a presença de esforço normal (tração e/ou compressão) nas ligações. Uma limitação empírica de 5% da resistência plástica da viga é a única condição imposta no Eurocode 3. O objetivo deste trabalho é realizar uma análise paramétrica de dois tipos de ligações aparafusadas para se avaliar a influência de combinações M/N no comportamento global destas ligações. Para se cumprir este objetivo, os resultados experimentais de quinze ensaios realizados por Lima [1] são comparados com os resultados obtidos através de um modelo analítico proposto por Cerfontaine [2], [3].
Traditionally, the steel portal frame design assumes that beam-to-column joints are rigidor pinned. Rigid joints, where no relative rotations occur between the connected members, transfer not only substantial bending moments, but also shear and axial forces. On the other extreme, pinned joints, are characterised by almost free rotation movement between the connected elements that prevents the transmission of bending moments. Despite these facts, it is largely recognised that the great majority of joints does not exhibit such idealised behaviour. In fact, many joints transfer some bending moments with associated rotations. These joints are called semi-rigid, and their design should be performed according to their real structural behaviour. However, some steel beam-to-column joints are often subjected to a combination of bending (M) and axial forces (N). The level of axial forces in the joint may be significant, typical of pitched-roof portal frames, sway frames or frames with incomplete floors. Current standard for steel joints do not take into account the presence of axial forces (tension and/or compression) in the joints. A single empirical limitation of 5% of the beams plastic axial capacity is the only enforced provision in Eurocode 3. The objective of the present work is to perform a parametrical analysis of two bolted joints types in order to evaluate the influence of M/N combinations in the joints global response. To fulfil this objective, the experimental results obtained by Lima [1] are compared to the analytical results using the Cerfontaine analytical model [2], [3].
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Yang, Yi-Fang, and 楊毅凡. "Behavior of Reinforced Concrete Beam-Column Sub-assemblage Subjected to Elevated Temperature－Behavior of Beam-Column Joint." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/30712838714097658363.
Повний текст джерелаАнотація:
碩士國立成功大學
土木工程學系碩博士班
95
The purpose of this research is to study the behavior of joint in a reinforced concrete beam-column sub-assemblage subjected to the effect of elevated temperature. In the experimental work, 4 full scale specimens of reinforced concrete beam-column sub-assemblage were tested, including 2 ordinary (NC) and 2 self compacting (SCC) concrete specimens. Two of the form specimens were tested in room temperature and the other two were tested in the elevated temperature, the displacement and rotation of joint were measured using the instruments installed at both ends of spandrel beam. The primary finding according to the test results are as follows： 1. The vertical displacement of joint of SCC and NC specimens in room temperature was about 4mm, and the rotation was about 0.2 degree. 2. The vertical displacement of NC joint tested in service lead and the elevated temperature was about 4~6 times of that tested in room temperature, where as the rotation in elevated temperature was about 7 times more. 3. For SCC joint subjected to three hours of elevated temperature test the temperature at it’s center was about 80℃, at the location 5cm near the center of longitudinal beam was about 100℃, and at the location 6cm near the corner was about 400℃ 4. The shear strength of joint was also studied in which the maximum allowable shear strength based on the prediction of ACT318 Code was 2480kN and 2716kN for NC1 and SCC1 specimen, respectively.
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Yen, Chih-han, and 顏志航. "Development of a New Type Beam Flange to Column Diaphragm Welding Joint." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/wby7s4.
Повний текст джерелаАнотація:
碩士國立臺灣科技大學
營建工程系
100
In traditional methods, the diaphragm most use of electric slag welding to joint with column, but the electric slag welding heat input is too large, resulting in the column plate became brittle. Therefore, this study presents a new beam-column connections method, named for WAWO or a New Type Beam Flange to Column Diaphragm Welding Joint”. We designed a series of specimens to do two types of test, one is the fatigue strength test and the other one is plastic rotation capacity test. The results showed that the fatigue strength, the traditional methods and the new methods were not significant. Plastic rotation capacity test results showed that in the traditional methods when the thickness of column plate is small the plastic rotation capacity is small, the new method is the opposite. The two test results show that the traditional method is not applicable in the column thickness is small, but the new method can apply to column plate thickness smaller, because the welding heat input is small. When the capacity of slot welding is large in the new methods may need to more test.
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Wu, Shiun, and 吳訓. "Seismic Beam to Wide Flange Column Joint in Steel Moment Resisting Frames." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/97982103216010792489.
Повний текст джерела
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Kim, Jaehong. "Joint shear behavior of reinforced concrete beam-column connections subjected to seismic lateral loading /." 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3301164.
Повний текст джерелаАнотація:
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007.Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 1179. Adviser: James M. LaFave. Includes bibliographical references (leaves 207-222) Available on microfilm from Pro Quest Information and Learning.
28
Bo-ChunFang and 方柏淳. "The Cyclic Loading Tests of Fire-Resistant Steel and Normal Structural Steel Beam-to-Column Welded Joint Specimens after Fire." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/37669487788317392956.
Повний текст джерелаАнотація:
碩士國立成功大學
土木工程學系
102
In order to study the post-fire mechanical behaviors of fire-resistant steel and normal structural steel beam-to-column welded joints under cyclic loadings, this thesis made three different types of beam-to-column welded joint specimens by the three different combinations of SN490C-FR fire-resistant steel and SN490B normal structural steel, which were fire-resistant steel specimens, partial fire-resistant steel specimens and normal steel specimens. Each type of specimens were divided to five groups and the five groups experienced five different temperature treatments, which were room-temperature treating, air-cooling after reaching 800ºC for one hour, water-cooling after reaching 800ºC for one hour, air-cooling after reaching 900ºC for one hour, and water-cooling after reaching 900ºC for one hour, respectively to simulate the possible material property variations of weld metal and base metal in the beam-to-column welded connections of steel buildings after fire. As a result, the fifteen beam-to-column welded joint specimens conducted the hardness test first to understand the hardness variations of the pre-fire and post-fire beam-to-column welded joints in the three different types of specimens. After the hardness test, the same fifteen specimens proceeded the cyclic loading test and the followed tensile test to investigate macro mechanical properties and failure modes of the pre-fire and post-fire beam-to-column welded joints in the three different types of specimens. This research found that the specimens with room temperature treating and the specimens with air-cooling after reaching the high temperature above 800ºC for one hour all fractured at the base metal. The air-cooled specimens were equivalent to the specimens with normalizing treating, which softened the base metal and the weld metal. However, the tensile strength of weld metal was still higher than that of base metal. As a result, the fracturing occurred at the base metal. The specimens with water-cooling after reaching the high temperature above 800ºC for one hour all fractured at the weld metal or the HAZ. The water-cooled specimens were equivalent to the specimens with quenching treating. The quenching treating made the austenite in the specimens transform to martensite. The more the martensite in the specimen, the higher the tensile strength of the specimen. The martensite content in a specimen was related to the carbon content of steel. Since the carbon content of base metal was higher than that of weld metal, the strength of base metal was higher than that of weld metal. As a result, the water-cooled specimens in this study fractured at the weld metal or the HAZ.
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Yuan-KaiTsai and 蔡元凱. "The Fast Tensile Tests of Fire-Resistant Steel and Normal Structural Steel Beam-to-Column Welded Joint Specimens after Fire." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/44971973716779425603.
Повний текст джерелаАнотація:
碩士國立成功大學
土木工程學系
102
In order to investigate post-fire behaviors of the fire-resistant steel and normal steel beam-to-column welded joints under fast tensile force, this study fabricated three kinds of beam-to-column welded joint specimens by SN490B normal structural steel and SN490C-FR fire-resistant steel, which were fire-resistant steel specimens, normal steel specimens and partial fire-resistant steel specimens. Each kind of the specimens were subject to five different temperature treatments (including room-temperature treating, air-cooling after reaching 800ºC for one hour, water-cooling after reaching 800ºC for one hour, air-cooling after reaching 900ºC for one hour, and water-cooling after reaching 900ºC for one hour) to simulate the post-fire material changes of weld metal and base metal in beam-to-column welded connections. This study conducted macroscopic examination, metallographic test, hardness test and fast tensile test for the specimens. The test results showed that, under the fast tensile forces, the normal steel specimen with the temperature treatment of water-cooling after reaching 900ºC for one hour broke at the HAZ between the ESW weld pass and the diaphragm plate with the failure mode of brittle fracture. The partial fire-resistant steel specimen broke at the HAZ between the FCAW weld pass and the beam flange plate with the failure mode of brittle fracture as well. Due to lack of fusion in the ESW weld pass, the fire-resistant steel specimen fractured at the lack of fusion zone between the ESW weld pass and the diaphragm plate with the failure mode of brittle fracture. All the other specimens broke at the base metal of beam flange plate or diaphragm plate.
30
Chi-HsuanChiang and 江奇軒. "Investigation on the Residual Strength of Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) Beam Column-Joint Subjected to Blast Loading." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/ymcw9f.
Повний текст джерелаАнотація:
碩士國立成功大學
土木工程學系
106
In recent years, many terrorist attacks on structures in the world have been carried out, and the explosions have caused great damage to the structure and major social costs for subsequent restoration. However, the design code this issue are relatively lacking . When the structural design is developed to the higher floor and the large-span space configuration, the demand for material strength and toughness is gradually increased, basis on this two major objectives ,the Ultra-High Performance Fiber Reinforced Concrete (UHPFRC)is developed. The finite element analysis software Abaqus is used to discussed the dynamic behavior of the UHPFRC beam-column joints under different blast condition and different column axial loading. After blast loading ,using push-over analysis to investigation on the residual strength compare to undamaged strength. It was found that UHPFRC beam-column joint can indeed provide a higher ultimate strength. When the beam-column joint is subjected to blast loading, the structure will have a partial dynamic reaction. Beside the damage concentrated at the interface between transform of the stirrups spacing because of the discontinuity on the stiffness. Under the different axial loading condition, when the beam-column joint is subjected to high axial loading , due to the better confining effect at the joint zone, so that the damage will be concentrated at the beam end , therefore the ultimate strength of push-over is less then low axial loading condition. Furthermore ,the above detailed information about the dynamic response of the beam-column joint, the push-over curve and the structural damage distribution at each time point are record for following research.
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Ya-JyunHu and 胡雅鈞. "The Numerical Simulations for the Cyclic Loading Tests of Fire-Resistant Steel and Normal Structural Steel Beam-to-Column Welded Joint Specimens after Fire." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/15701693540491448806.
Повний текст джерелаАнотація:
碩士國立成功大學
土木工程學系
103
This study used a 3D nonlinear finite-element software to develop simplified numerical models of the cross-shaped weld zones of beam-to-column welded joints, and to performed numerical simulations of the simplified cross-shaped weld zone numerical models for investigating the post-fire mechanical behaviors of the cross-shaped weld zones of fire-resistant and normal structural steel beam-column joints under tensile-compressive cyclic loadings. In addition, the strain hardening parameters of the fire-resistant grade and normal grade steel materials and weld metals under cyclic loading before and after fire were incorporated into the numerical models to simulate the cyclic loading test results of the fifteen simplified cross-shaped specimens. The fifteen specimens were composed of three types of steel allocations (i.e., fully normal structural steel allocation, partially fire-resistant steel allocation and fully fire-resistant steel allocation) and five temperature treatments (i.e., room-temperature treatment, air-cooling after reaching 800ºC for 1 hour, water-cooling after reaching 800ºC for 1 hour, air-cooling after reaching 900ºC for 1 hour, and water-cooling after reaching 900ºC for 1 hour). The numerical simulation results were compared with the realistic test results for the related investigations. This study found that compared with the test results, the numerical results damaged earlier and their maximum tensile forces were 10% to 15% lower. Therefore, the numerical results were more conservative.
32
Santiago, Aldina Maria da Cruz. "Behaviour of beam-to-column steel joints under natural fire." Doctoral thesis, 2008. http://hdl.handle.net/10316/7543.
Повний текст джерела
33
Hoffschild, Thomas E. "Retrofitting beam-to-column joints for improved seismic performance microform." Thesis, 1992. http://hdl.handle.net/2429/2461.
Повний текст джерелаАнотація:
Before the 1970's, most codes for the design of reinforced concrete structures did not include provisions for ductility during seismic events was not prevalent in most codes. The guidelines that did exist were minimal, and often left a fair amount of room for interpretation by the design engineer. Hence, many of the reinforced concrete structures designed during that time are suspect under today's more stringent design guidelines. Moreover, even the present designs are often deficient and vary from building to building and from jurisdiction to jurisdiction.
This report is a presentation of the findings of an experimental study to evaluate a method of retrofit which addresses a particular weakness that is often found in reinforced concrete structures, namely the lack of sufficient reinforcement in and around beam-to-column joints. Many of these structures lack the required confining reinforcement within the joints and in adjoining beams and columns. The result is a reinforced concrete framethat is weak in the joint area and lacks sufficient ductility during a seismic event.
The proposed retrofit method consists of encasing the reinforced concrete joint with a grouted steel jacket that provides confinement to the joint area, and imparts ductility to the frame. In this study, two styles of retrofit jacket were tested: a circular steel tube and a rectangular casing. It was found that circular steel jackets have the advantage of providing direct concrete confinement and, as well, of furnishing a ductile force transfer mechanism through the jacket itself, but are also more difficult and expensive to fabricate than rectangular jackets. Although rectangular jackets do not provide the same degree of concrete core confinement as circular jackets, the amount available seems sufficient to prevent damage in the joint area. The load transfer mechanism of the rectangular jackets was found to be adequate in withstanding the loads and deflections typical for seismic events.
In this thesis, the two jacket styles are evaluated for strength, stiffness and ductility, and their relative merits are discussed.
34
Hasaballa, Mohamed. "GFRP-reinforced concrete exterior beam-column joints subjected to seismic loading." 2014. http://hdl.handle.net/1993/24454.
Повний текст джерелаАнотація:
Glass fibre-reinforced polymer (GFRP) reinforcement is used in reinforced concrete (RC) infrastructure to avoid steel corrosion problems. The behaviour of GFRP reinforcement under seismic loading in RC frame structures has not been widely investigated. The behaviour of beam-column joints significantly influences the response of the Seismic Force Resisting Systems. Therefore, both the design and detailing of the beam-column joints are critical to secure a satisfactory seismic performance of these structures. However, the current Canadian FRP design codes (CSA 2012, CSA 2006) have no considerable seismic provisions, if any, due to lack of data and research in this area. Such lack of information does not allow for adequate designs and subsequently limits the implementation of FRP reinforcement as a non-corrodible and sustainable reinforcement in new construction. Therefore, it deemed necessary to track areas of ambiguity and lack of knowledge to provide design provisions and detailing guidelines.
This study investigated the seismic behaviour of the GFRP-RC exterior beam-column joints. The study consisted of an experimental phase, in which ten full-scale T-shaped GFRP-RC specimens were constructed and tested to failure, and an analytical phase using finite element modelling (FEM). Specimens in the experimental phase were designed to investigate the anchorage detailing of beam longitudinal reinforcement inside the joint (using either bent bars or headed bars) and to evaluate the shear capacity of the joint.
In the analytical phase, a commercial FEM software (ATENA-3D) was used to run a parametric study that investigated the influence of the presence of lateral beams, axial load on the column, applied shear stresses in the joint, and the concrete strength.
Test results showed that the performance of the specimens reinforced with GFRP headed bars was comparable to their counterparts reinforced with bent bars up to 4.0% drift ratio. The difference in the reinforcement surface conditions had insignificant influence on the overall behaviour. Moreover, it was concluded that the shear capacity of GFRP-RC beam-column joints is 0.85 √f'c. Furthermore, an evaluation of the relevant seismic provisions in the CSA/S806-12 (CSA 2012) was carried out and some recommendations were proposed for consideration in the future updates of the CSA/S806-12.
35
Lin, Ker-Chun, and 林克強. "Seismic Behavior of Beam-to-CFT Column Joints using External Clamping Diaphragms." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/15267437125723293744.
Повний текст джерелаАнотація:
博士國立臺灣大學
土木工程學研究所
88
Concrete filled tube (CFT) column usually possesses high axial load and high ductility characteristics that distributes to the contribution of confinement by steel tube. However, for a seismic structural system with the CFT columns, it is necessary that beam-to-column connections possess sufficient strength and ductility. In traditional internally or externally stiffened connections for CFT columns, the complete penetration welds were used to connect beam flange to column or diaphragm. Past research experience and earthquake damages indicate that fractures on these connections frequently occurred at the complete penetration welds or the adjacent base material. The premature fractures are the key factor for the poor plastic rotation capacity of connections. In addition, internal diaphragms in the steel tube column reduce the effectiveness of concrete filling work. Past test results on steel beam to RC column joints using internal clamped diaphragm connection show that beam plastic rotation can exceed 0.03 radian without any fracture occurring in the fillet weld or base material. Related analytical study illustrated that stiffness of beam-to-steel tube column connection using external clamping diaphragm is higher than the stiffness of connection with internal diaphragm. It clears the concept under most engineers’ mind that the connection’s stiffness with external diaphragms is always less one using internal diaphragm. In this dissertation, the beam-to-CFT column connections using external clamping diaphragms (ECDs) including reentrant and extended configurations are assessed. There are thirteen full scale beam-to-CFT column connection specimens that include three ones with extended ECDs and ten ones with reentrant ECDs. Experimental failure modes indicate that special end return fillet welds between diaphragm and beam flange effectively prevent the tearing fracture of the fillet weld. Further, if the difference in thickness between the diaphragm and the beam flange is too excessive, the diaphragm bending deformation is more difficult to conform with the beam deformation. The possibility of tearing fractures of the weld will increase and result in reduction of plastic rotation capacity of the connections. Test results also indicate that the stiffness of extended ECD connection details is smaller than the ones with the reentrant ECDs. Therefore, the connections using external reentrant ECD are not only more economical but also perform better than the ones using extended ECDs. The experimental results demonstrate that properly constructed connections using the reentrant ECD details can provide a plastic rotation greater than 3% radian, even up to 5% radian and at least 2.31% radian. Simultaneously, Based on nonlinear dynamic analysis results for a six-story building with CFT column MRF, the demand plastic rotation of 1.89% radian for the building subjected to earthquake records of Taipei basin with PGA of 250gal. In addition, the well proportioned beam-to-CFT column connections with ECD details can stably develop beam plastic moment strength with an average strain-hardening factor of 1.16. For practical designs, a proposal value of strain hardening factor for the connection is at least 1.2. Further, the “fracture-yielding-yielding” block shear model, proposed in this paper, can exactly predict the fractured block shear strength in beam flange. In addition, test and analytical results also find that the utlimate shear strength of panel zone in the CFT column may not be directly superposed by the ultimate shear strengths of concrete and steel tube’s webs. This is because the shear strength of concrete has been fully developed before the average shear deformation of panel zone reaches the yield shear strain of steel webs. Moreover, the shear strength of panel zone is almost provided by steel web as the average shear deformation of panel zone reaches the yield shear strain of steel webs.
36
Rehman, Hafiz Muhammad Ubaid Ur. "FEM analysis of the cyclic behaviour of steel beam-to-column joints." Master's thesis, 2018. http://hdl.handle.net/10316/84873.
Повний текст джерелаАнотація:
Dissertação de Mestrado em Construção Metálica e Mista apresentada à Faculdade de Ciências e TecnologiaA análise e dimensionamento de estruturas metálicas devem considerar todos os tipos de ações que esta possa ser submetida ao longo do seu período de vida útil. A ação sísmica é uma ação particularmente severa que tem que ser cuidadosamente considerada. Neste cenário, as ligações viga-pilar de estruturas metálicas devem ser dimensionadas de forma a evitar modos de rotura frágeis. Para este efeito, o dimensionamento das ligações viga-pilar de estruturas metálicas deve ser levado a cabo seguindo as prescrições da EN 1998, EN 1993 e da EN 1993-1-8 em particular, fazendo do método das componentes.A análise experimental é o método tradicionalmente usado pela comunidade científica para avaliar o comportamento cíclico de ligações viga-pilar metálicas. No entanto, a caracterização do comportamento cíclico das ligações metálicas ao nível das componentes diretamente a partir dos resultados experimentais não é viável. Desta forma, são necessários modelos numéricos avançados desenvolvidos e validados com base em ensaios experimentais.Nesta dissertação são desenvolvidos modelos com base no Método dos Elementos Finitos para avaliar o comportamento monotónico e cíclico das zonas tracionadas de ligações viga-pilar metálicas, focando esta análise no comportamento da componente banzo dos pilar em flexão. Este trabalho enquadra-se no âmbito do projeto EQUALJOINTS.................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
The construction of a structure undergoes several stages, each of which must be thoroughly thought. In structures that may be subject to seismic actions at some point of their use life, these considerations are especially significant. Joints between steel elements in this type of structures should always be designed, fabricated and erected such that brittle failure is avoided and a ductile mode of failure governs the collapse. Designers must always bear in mind design requirements set by the relevant design standards. In Europe, EN1998 must be observed for the seismic design of structures, with significant reference to EN1993 for the design of steel structures and EN1993-1-8 in particular for the design of steel joints making use of the components method.Nowadays the experimental test is the preferred method between the scientific community to assess the seismic behavior of steel joints. However, the analysis of the seismic behavior of beam-to-columns joints at component level directly from the analysis of the results of the experimental test is unfeasible. Accordingly, advanced numerical models must be developed and validated with the experimental tests. The aim of this dissertation is to develop advanced FEM based models for the simulation of cyclic tests of T-Stub of steel beam-to-column joints tested in the scope of “European pre-qualified steel joints (EQUALJOINTS) Grant agreement no. RFSR-CT-2013-00021” project. These models will allow to extract and characterize the cyclic behaviour of the components of the joint
37
Baraka, Miljenko. "Numerical modelling of experimental data of reinforced concrete beam-to-column joints." Thesis, 1996. http://hdl.handle.net/2429/5725.
Повний текст джерелаАнотація:
Since the 1970's, increasing attention has been given to seismic design in building
codes with emphasis on ductility. Ductile behaviour in reinforced concrete moment
resisting frames is important from the point of view of an energy dissipating mechanism.
Modern design codes today have stringent guidelines on the design of the beam to
column joint region in order to achieve ductile behaviour without brittle shear failure.
There are many older buildings, however, that are deficient in strength and ductility with
respect to seismic loading. Deficient structures such as these may be retrofitted by
encasing the beam to column joint in a steel shell.
Cyclic testing of reinforced concrete beam and column sub-assemblies have
proven that a very substantial increase in bending and shear strength can be achieved in
the joint area by encasing the region with a steel tube and filling the cavity with cement
grout. Failures were deflected from the joint area to adjacent members, which were
intentionally weakened to form plastic hinges. Subsequent tests on the remaining joint
specimens, which forced the failure mechanism into the joint region, provided strength
and ductility data for the joint itself.
Because experimental testing of scale models can be expensive and at times
impractical for every situation that may arise in practice, a non-linear finite element
program was written for the analysis of the joint area. The program utilizes plasticity
based constitutive descriptions of the concrete and steel material models and intends to be
able to predict the behaviour and peak values of the strength envelopes of the joints.
Comparisons with available experimental results were encouraging insofar as the plastic
behaviour of the concrete and steel were captured. Due to the complex nature of the
problem the program was unable to accurately predict the maximum load carrying capacity and more research is required in "fine tuning" the material constitutive models
and finite element models. Recommendations for continuing research are given.
38
Hsieh, Hsin-Lun, and 謝欣倫. "Seismic Design of Diaphragm Plate in Steel Beam-to-Box Column Joints." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/27961228199912105865.
Повний текст джерелаАнотація:
碩士國立臺灣大學
土木工程學研究所
100
Built-up box columns are widely used for steel structures in Taiwan because of its bi-axial strength and stiffness. In the welded beam-to-column moment connections, welded internal diaphragms in the column at the beam flange elevations play an important role in transferring the beam flange forces into the column. For an interior column, two beams are connected to the opposite flanges of the box column, while only one beam for an exterior column. In common practice, the thickness of the diaphragm plate is the same as the beam flange thickness in either interior or exterior column. Most of the tests on welded beam to box column moment connections have been conducted for exterior columns. Under the severe earthquake loads, the diaphragm plates having a thickness identical to the beam flange may go into severe inelastic responses when both two beams develop plastic hinge adjacent to an interior column. This research investigates the deformations and stress distributions, quantifies the force demand, and proposes the seismic design method for diaphragm plates in box columns. First, this paper presents the difference on stress responses in diaphragms between the exterior and interior connections using finite element (FE) software, ABAQUS. The shell element model was calibrated first using a beam-to-exterior box column connection specimen. Then extensive FE analysis results show that diaphragm peak shear stresses near the column web in the interior column is almost twice of those of in an exterior column. However, diaphragm peak normal stresses near the column flange are similar in both two types of connections. In order to allow designers to efficiently size the diaphragm thickness, this paper proposes two approaches to quantifying the seismic force demand on the diaphragm. One is based on the relative flexibilities of the column flange and diaphragm. The other is based on the simplified free body diagram. The simplified approach is convenient and conservative. The FE analysis results indicate that the deformation and von Mises stress in the interior column diaphragm are much larger when the diaphragm thickness is the same as the beam flange. The diaphragm plate, thickness determined from the proposed method reduces the peak diaphragm deformation by 75% and allows the diaphragm to remain elastic when plastic hinges form on both two beams. The FE analysis results also indicate that the equivalent cumulative plastic strain and rupture index on beam flange edge caused by diaphragm yielding are much higher in an interior connection than those in the exterior connection. The paper concludes that further experimental tests are desired in order to gain insights into the effects of diaphragm plate responses on rotational capacity of welded beam to interior box column moment connections.
39
Chen, PeiChing, and 陳沛清. "A Study of RC Column-to-Foundation and Steel Beam-to-RC Column Joints for An RCS Frame Specimen." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/45140523250624627974.
Повний текст джерелаАнотація:
碩士國立臺灣大學
土木工程學研究所
90
A joint research effort among US, Japan and Taiwanese researchers on large scale frame testing of steel and concrete composite structures has been launched in 2001. It is the consensus that a 2-D full-scale three-story three-bay RCS moment resisting frame be constructed and tested in the NCREE to accelerate the world-wide implementation of RCS structural systems in real application. In this research, cyclic tests were conducted on the roof beam-to-RC column and the RC column to foundation subassemblage specimens. In this research, a total of six specimens have been fabricated and tested in order to investigate the effectiveness of three different kinds of connection details. It includes: (a) the splice location effects on the 1st floor RC column to the foundation joint (FF series specimens), (b) the axial load effects to the responses of RC column (FR series specimens), (c) the anchorage details of the roof interior RCS beam-to-column joint (R series specimens). FF series experimental results show that the performance of the one-meter high splice location is better than that on the top face of the foundation. FR series experimental results show that higher axial loads make higher column flexural strength. R series experimental results show that the proposed reinforcing anchorage end plate details can satisfactorily provide the needed anchorage for column bars. For FF and FR specimens, the analytical moment versus curvature relationships were computed. It assumes plane remains plane after bending and incorporates the low-cycle fatigue and the soften-branch model for the vertical reinforcement and the Mander’s confined concrete model. It is illustrated that the experimental cyclic cantilever column load versus displacement response skeleton curves can be accurately predicted by employing the Moment-Area Method. For R series specimens, the column end lateral displacements due to column deformations, beam deformations, panel zone bearing deformations and panel zone shear deformations can be separated by the proposed method. Good agreements with the subassemblage test results are also observed in the analytical cyclic responses simulated by using a general-purpose inelastic structural analysis software PISA2D. The complete three-story three-bay analytical RCS frame model is also constructed and calibrated based on the test results. Finally, nonlinear static and dynamic time-history analyses are performed in order to investigate the most possible ultimate lateral strength and the inelastic demands imposed on the frame specimen under the simulated earthquake effects.
40
Mikheeva, Margarita. "Numerical analysis of compressed components of beam-to-rectangular hollow section column moment resistant steel joints." Master's thesis, 2017. http://hdl.handle.net/10316/83228.
Повний текст джерелаАнотація:
Dissertação de Mestrado em Construção Metálica e Mista apresentada à Faculdade de Ciências e TecnologiaHollow sections appear to be very attractive from the architectural and structural point of view. They exhibit high aesthetic performance along with significant resistance to compression, bending and torsion. Additionally, hollow sections show higher durability and corrosion resistance comparing to opened sections.However, connecting to hollow sections is a demanding procedure. The absence of the access to the interior void of hollow sections leads to the necessity of developing appropriate types of joints which would allow to balance design, fabrication, erection and operation stages with the overall project cost.The range of possible connections of beams to hollow sections is already invented. Nevertheless, there is always a challenge to develop connection types with improved characteristics. The present thesis is a part of the wider research of beam-to-rectangular hollow section column moment resistant joint subjected mainly to the action of the bending moment. The main research project is divided into three parts, investigation of compressed components of the joint, tension components of the joint and the global joint. Each part contains experimental tests, numerical modeling and analytical characterization of the joint behaviour. The goal of the thesis is to investigate the behaviour of compressed components of the joint by numerical modeling. Numerical results are further validated by comparison to experimental data. Numerical simulations are carried out by DS Simulia Abaqus software. The thesis includes numerical analysis of four models corresponding to experimental specimens which represent compressed components of the joint. After the calibration of obtained results the parametric study is implemented for 104 numerical models more. The parametric study aims to investigate the behaviour of the components for the extended range of geometrical variation.The result of the present thesis is the information about resistance and stiffness of the compressed components of the joint based on the force - displacement response which is obtained for the total number of 108 numerical models.
Hollow sections appear to be very attractive from the architectural and structural point of view. They exhibit high aesthetic performance along with significant resistance to compression, bending and torsion. Additionally, hollow sections show higher durability and corrosion resistance comparing to opened sections.However, connecting to hollow sections is a demanding procedure. The absence of the access to the interior void of hollow sections leads to the necessity of developing appropriate types of joints which would allow to balance design, fabrication, erection and operation stages with the overall project cost.The range of possible connections of beams to hollow sections is already invented. Nevertheless, there is always a challenge to develop connection types with improved characteristics. The present thesis is a part of the wider research of beam-to-rectangular hollow section column moment resistant joint subjected mainly to the action of the bending moment. The main research project is divided into three parts, investigation of compressed components of the joint, tension components of the joint and the global joint. Each part contains experimental tests, numerical modeling and analytical characterization of the joint behaviour. The goal of the thesis is to investigate the behaviour of compressed components of the joint by numerical modeling. Numerical results are further validated by comparison to experimental data. Numerical simulations are carried out by DS Simulia Abaqus software. The thesis includes numerical analysis of four models corresponding to experimental specimens which represent compressed components of the joint. After the calibration of obtained results the parametric study is implemented for 104 numerical models more. The parametric study aims to investigate the behaviour of the components for the extended range of geometrical variation.The result of the present thesis is the information about resistance and stiffness of the compressed components of the joint based on the force - displacement response which is obtained for the total number of 108 numerical models.
41
Tung, Ham-Yu, and 董瀚友. "TEST PERFORMANCE OF REINFORCED CONCRETE BEAM-TO-COLUMN JOINTS RETROFITTED OR REPAIRED BY CONCRETE JACKET." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/92836653903709442768.
Повний текст джерела
42
Chin, Chih-Kuang, and 覃志光. "Seismic performance of SM570M-CHW steel beam-to-column joints with eccentricity among electroslag welding, diaphragm and beam flange alignment." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/fwy5m8.
Повний текст джерелаАнотація:
碩士國立臺灣大學
土木工程學研究所
105
Tall buildings are getting taller and taller in the mega cities all over the globe. The need of using SM570M-CHW high-strength steel for building constructions in Taiwan is increasing. In order to transfer the beam moment, diaphragms at the beam flange elevations are often welded into the built-up box column using the electro-slag welding (ESW). However, the elevations of the diaphragm, the ESW and the beam flange may not be perfectly aligned. This could be caused by the fabrication error or the slight difference of the depths of two beams framing into the column. The misalignment in beam flange and diaphragm, with or without the eccentricity of ESW, may lead to the brittle fracture due to stress concentrations near the ESW to column flange heat affected zone (HAZ). This study uses the damage prediction model proposed by Kanvinde and Deierlein to investigate the damage potential of ESW component specimens using SM570M-CHW steel with the eccentricity between the beam flange and the ESW. The Abaqus model analysis results are compared with the experiment observations. The ESW component was constructed from a SM570M-CHW steel 500×500×28mm box column with 200×28mm beam flanges. The ESW eccentricity was measured using ultrasonic tests (UT), specimens with various eccentricities between the beam flange and the diaphragm were constructed. The damage prediction models are applied to predict the critical strength and displacement of the ESW components test results. Experiment and analysis results suggest that the eccentricity between the beam and the diaphragm must be no greater than three fourth of the column flange thickness in order to prevent the brittle fracture at the HAZ. The analytical results with varying column thickness indicate that increasing the column flange thickness reduces the abovementioned fracture potential effectively.
43
Piscini, Andrea. "Passing-through Tubular Column Joints for Steel and Composite Constructions made by Laser Cutting Technology." Doctoral thesis, 2020. http://hdl.handle.net/2158/1222586.
Повний текст джерелаАнотація:
In steel moment-resisting frames, tubular columns have many structural and architectural advantages over open-section columns. Circular Hollow Sections (CHS) are in fact particularly recommended for structural elements subjected to compression and bending forces in all directions, thanks to their higher radius of gyration and the axial-symmetric distribution of their mechanical properties. Therefore, the use of CHS profiles for the realization of columns can lead to a reduction of the total costs and furthermore to simplifications in the realization process of steel-concrete composite structures. However, the difficulties in realizing tubular column joints adopting open I-section beams, the most commonly used all around the world, severely reduce the use of CHS columns.
Nowadays, I-beam-to-CHS-column steel and composite joints are commonly realized in two main ways: i) the connection is made by directly welding the beams or the beam stub to the wall of the steel tube; ii) supplemental plates are used to connect the beams to the circular column. The direct connection is the most convenient solution in terms of rapidity and easiness of fabrication but the performance of the joint is strongly limited by significant local distortions of the tube wall near the girder flanges. Therefore, the joint performance results very far from the ideal mechanical behavior of a rigid full-strength beam-to-column connection.
The local buckle of the tube wall, which can lead to brittle failures, often suggests the use of supplemental plates for the realization of the tubular column joints. Additional elements can indeed assure a more effective transfer of the stresses from the beam flanges to the column wall or from the flanges of one beam directly to the beam placed on the opposite side. In general, two types of additional elements are currently used for I-beam-to-CHS-column moment joints: interior diaphragm joints, which imply the discontinuity of the column, and exterior diaphragm joints, which guaranty the total continuity of the column. Although internal diaphragms are very effective in distributing the internal forces and improving the collaboration between the steel elements and the concrete core in the case of composite columns, their use implies a discontinuity in the column and requires extensive welding to reconnect the column pieces. On the contrary, exterior diaphragms guarantee the steel tube continuity through the connection; nevertheless, several welding should be performed also in this case. Moreover, in the case of filled column, the composite behavior is not improved by the presence of steel elements, and the presence of big external stiffeners spoils down the aesthetic of the whole building.
To overcome the main issues inherent the direct connections and the use of diaphragms, innovative solutions with continuous passing-through elements inside the column were studied, highlighting several advantages from a mechanical point of view. Indeed, the continuous elements can pass by slots of limited size made on the column wall, without requiring the complete discontinuity of the column itself and the joint requires less cutting and welding operations, resulting in lower overall cost and better mechanical behavior. The use of passing-through elements can lead to obtain the same mechanical benefits highlighted by internal diaphragms joints, without requiring the complete discontinuity of the column wall in the joint. However, despite all these advantages, many problems arise from the fabrication and constructional points of view, limiting the effective performance of the joints. Indeed, the difficulties in implementing high precision cutting processes spoiled the development of this construction technique, favoring more practice solutions.
One of these difficulties lies in the production tolerances that affect the effective geometry of the beams. These tolerances shall be considered in the definition of the dimensions of the slots in which the beams need to pass through: dimensions of the slot very close to the nominal ones of the beam can lead to difficulties in the assembly process, whereas big gaps can result in ineffective welding. One of the solutions to overcome the difficulties in the fabrication and constructional processes of this joint typology lies in the application of the modern Laser Cutting Technology (LCT) to steel and composite structures. Laser cutting machines, commonly used in the industrial field, allow performing high precision and completely automated cutting processes on steel tubes and open sections profiles with the typical structural dimensions. To limit the influence of the beam dimensions tolerances, the laser cutting machines have the intrinsic advantage of directly providing measuring instruments that can be used to measure the elements to be passed. Therefore, the whole fabrication process can start with the simultaneous cutting and measuring process of the I-beams and plates. Subsequently, slots can be realized on the tube-wall considering the previously taken and recorded measurements and applying a defined strict tolerance margin. In this way the correct passage of the beam portions or plates through the column is guaranteed without requiring excessive gaps, and the welding processes is performed in the best conditions. Furthermore, thanks to the possibility of cutting with different inclinations with the tube-face, the penetration welding may be realized without performing any additional preparation processes on the worked-pieces. The LCT is also a very competitive solution in terms of time of fabrication and cost, thanks to the high automatization of the process reached by the modern technologies.
However, even though the LCT provides the perspective of realizing the I-beam-to-CHS-column connection type that exhibited the best mechanical behavior in the past researches, several issues still need to be faced in order to define an appropriate fabrication process and to better characterize the behavior of the I-beam-to-CHS-column connection. For these purposes, in the presently exposed research, preliminary practical, numerical and theoretical studies are conducted to confirm the mechanical and technological advantages previously reported, and to understand the global and local behavior of the passing-through tubular column connections in case of both vertical and horizontal loadings acting on the structure.
Considering the analyzed aspects inherent the practical realization and the mechanical behavior of the I-beam-to-CHS-column with passing elements, new joint solutions are proposed for both steel and composite structures. Afterwards, the proposed joint typologies are experimentally tested in order to have information on their mechanical behavior. On the basis of the behavior exhibited in the tests, mechanical models for steel and composite joints are developed with the aim of drafting practical methods for the definition of design forces acting on the singular components, and global elastic stiffness and strength of the joints.
44
Wu, Chung-Che, and 吳忠哲. "Fracture Tests and Finite Element Analysis of Diaphragm Connection in Steel Beam-to-Box Column Joints." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/27835414672911953746.
Повний текст джерелаАнотація:
碩士國立臺灣大學
土木工程學研究所
104
Steel box columns are widely used in steel building structures in Taiwan because of the strong axes in two directions. In order to transfer the beam end moment to the column, diaphragm plates of the same thickness and elevations as the beam flanges are usually welded inside the box column. The electro-slag welding (ESW) process is usually used in attaching the diaphragms to the column flanges. This ESW process has been widely used in steel beam-to-box column joints in Taiwan because of its’ convenience and efficiency. However, the ESW may increase the hardness of the welds and heat affected zones (HAZs), while reduce the Charpy-V Notch (CVN) strength in the HAZ. This situation could cause the diaphragm to column flange weld to suffer premature fracture before a large plastic rotation is developed in beam-to-box column joints. Results of 22 full scale steel beam-to-box column connection tests conducted in 2008 by Lin et al. show that the probability of ESW fracture at the HAZs adjacent to the ESW is about 18%. Cheng et al. continued the study in 2011 with new tests on full scale beam-to-box column subassembly and ESW components. Test results show that the fractures of the diaphragm-to-column flange welds are sensitive to the eccentricity between the elevations of the ESW and the beam flange. In order to quantify the critical eccentricity and the effectiveness of predicting the fractures, this study adopts the fracture prediction model proposed by Kanvinde in 2004 and utilizes finite element model (FEM) analysis to correlate the test results. In this study, two additional beam-to-box column connection subassembly tests have been conducted with a different loading protocol or the shape of ESW chamber. It is found that the fractures of the aforementioned HAZs can be reasonably well predicted using the proposed procedures on applying the fracture model. Test results show that under the standard and increasing loading protocols, the instances of the HAZ fractures in the specimens correspond to the total beam end deformations of the 2nd and 1st cycles of 0.03 radian, respectively. It is confirmed that the fracture instances can be predicted based on the cumulative plastic deformation in the HAZs. Under the two same standard loading protocol, the flared ESW chamber alter the fracture location from the HAZ in the diaphragm weld to the beam flange weld, and delay the fracture at the 2nd cycle of 0.03 radian to the 1st cycle of 0.04 radian. Tests confirm that the possible fracture of the diaphragm to column flange welds can be mitigated by enlarging the chamber of the ESW. When the fracture prediction model is applied, the material parameters were firstly established from the Circumferential Notched Tensile (CNT) tests and FEM analysis. Subsequently, these parameters were used to predict the fractures observed in the ESW component tests and beam-to-box column connection subassembly tests. The fracture locations and instances can be reasonably well predicted by a suitable FEM model analysis. Thus, the effectiveness of CNT and the fracture model are confirmed. Analytical results also show fracture instances and locations are sensitive to the relative locations of the ESW and the beam flange. Thus, the importance of ultrasonic test in assuring the quality of the ESW is evident. Finally, a parametric study on the eccentricity between the ESW and beam flange locations is conducted using 45 models with various vertical and horizontal eccentricities of ESW with respect to the beam flange. The parametric study results show that the size of critical zone of ESW is indeed the most important factor affecting the fracture instance. When the relative vertical eccentricity between ESW and beam flange is increased, the fracture instances is accelerated. Enlarging the critical zone of ESW effectively reduces the possibility of fracture as evidenced by using a flared shape ESW chamber in the aforementioned test specimen.
45
Shih-MingWang and 王士銘. "The Post-Fire Experiment of Steel Beam-to-Column Welded Joints Using Small-Scale Tension Specimens." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/56397917177789650399.
Повний текст джерела
46
Lin, Ying-Ru, and 林英如. "Database Construction and Parameter Study of High-Strength Reinforced Concrete Beam-Column Joints Subjected to Cyclic Load Reversals." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/55245790647143401322.
Повний текст джерелаАнотація:
碩士國立雲林科技大學
營建工程系碩士班
99
This paper presents a database consist of 110 beam-column joint specimens made of high-strength concrete (above 40 MPa) and reinforcement (above SD490), containing 53 cruciform and 57 T-shape beam-column joint specimens,which were tested by Japanese researchers in the past 15 years. Test results were investigated for revising design recommendations of beam-column joints with high-strength reinforcement and concrete. Parametric study of the database showed that we could extend current ACI design rules for high-strength reinforcement with modified requirements of joint transverse reinforcement and development lengths. Based on available test data we conclude: (1) Yield story drifts of beam-column joint can be well estimated using Priestley’s formula; (2) Maximum tensile reinforcing ratio of a beam section should not exceed 0.025 and 1.5√(f_c^'' )/f_y in MPa to insure the beam yielding before joint shear failure; (3) The failure modes and failure points can be predicted by an empirical joint shear strength-ductility model with modification factors of bond and confining conditions. Provided information may be referred for updating the design recommendations of beam-column joints.
47
Yeh, Yu-Hsiang, and 葉玉祥. "A Preliminary Study on The Beam-to-column Joints in the Veranda of the Japanese-style Wooden Train Stations." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/60063245308260327767.
Повний текст джерелаАнотація:
碩士國立成功大學
建築學系碩博士班
92
In Taiwan, there are a lot of Japanese-style timber train stations that were built in Japanese Colonial Period. These train stations are the indicator of the import history of the Japanese-style timber buildings. They have existed for least 60 years. Now many of these timber train stations are deteriorated and lack of maintenance. The main goal of the thesis is to discover the rotational stiffness and ultimate moment resistance of the beam-to-column connections of these stations by experiment. In the future, a reliable structural evaluation method would be developed after understanding the structural behaviour of these connections. If, before restoration, it needs to assess the seismic resistance of these timber train stations, the evaluation method would be helpful. Firstly, the investigation about the beam-to-column connections of these timber train stations will be carried out to understand the types of the connections. The object of the investigation is the connection in the veranda of the timber train station. Then the connections will be categorized into several types according to the variances in construction and the details. In the research, the most popular type of the connections will be discussed. The emphasis of the experiment is to understand the influence of the construction variances on structural characteristics, including the height of the beam, the span of the bracing and the peg in the connections. Two advises about the restoration will be provided after the analysis.
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Davison, J. B., Dennis Lam, and D. A. Nethercot. "Semi-rigid action of composite joints." 1990. http://hdl.handle.net/10454/5625.
Повний текст джерелаАнотація:
The results of a pilot series of tests, designed to investigate the influence of the presence of a composite floor slab on the performance of steel beam-to-column connections, are reported. Direct comparisons against equivalent bare steel tests show improvements in moment capacity (up to 15 times), with reinforcement anchorage being the main controlling factor. Thus joints to internal columns where the deck runs parallel to the beams and relatively small numbers of bars supplement the basic mesh reinforcement may be expected to give the best performance.
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Ying-ChihHuang and 黃英誌. "The Toughness Study on the Base and Weld Materials of Fire-Resistant Steel and Normal Structural Steel Beam-to-Column Welded Joints after High-Temperature Fire." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/76eg7s.
Повний текст джерела
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Rodrigues, Filipe Augusto Coelho Ramos. "Validação do dimensionamento de ligações metálicas de grandes dimensões." Master's thesis, 2019. http://hdl.handle.net/10316/86741.
Повний текст джерелаАнотація:
Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e TecnologiaO método das componentes, ao permitir avaliar o comportamento de uma gama alargada de configurações de junta, estabeleceu-se como o método de referência para o dimensionamento de juntas metálicas, sendo por isso codificado no Eurocódigo 3 – Projeto de estruturas de aço, Parte 1-8: Projeto de ligações. Ainda assim, este método apenas foi calibrado para juntas de dimensões usuais.Os modelos 3D de elementos finitos atualmente são uma ferramenta com imenso potencial pois permitem considerar fenómenos complexos relacionados com não linearidades materiais e geométricas, mas cuja utilização ainda não é uma realidade.Nesta tese é levado a cabo a avaliação do comportamento de duas juntas metálicas de grandes dimensões. Esta avaliação é feita recorrendo ao método das componentes e ao método dos elementos finitos cujos resultados são confrontados com resultados de ensaios experimentais realizados.Este trabalho permitiu concluir que o método das componentes conduz a estimativas conservadores para a resistência e para a rigidez das juntas e que o método dos elementos finitos pode conduzir a boas estimativas para o comportamento das juntas, mas, para isso, as condições de fronteira dos provetes de ensaio devem ser perfeitamente definidas.Este trabalho permitiu ainda concluir que o método dos elementos finitos é uma ferramenta com muitas potencialidades que permite uma caracterização muito rigorosa do comportamento efetivo das juntas. No entanto, a sua utilização para o efeito de projeto tem custos proibitivos na medida em que exige muito tempo para criar e correr os modelos, mas também know-how para definir não só os modelos materiais bem como as malhas.Conclui-se desta forma que o método das componentes é perfeitamente aplicável a ligações de grandes dimensões e é o método com melhor relação custo/benefício para utilização em ambiente de projeto.
The component method, by allowing the evaluation of the behaviour of a wide range of joints configurations, has been established as the reference method for the design of steel joints and being therefore encoded in Eurocode 3: Design of steel structures – Part 1-8: Design of joints. However, this method was only calibrated for joints with usual dimensions.The 3D models of finite elements are currently a tool with high potential because they allow to consider complex phenomena related to material and geometric nonlinearity but whose use is not yet a reality. In this thesis the behaviour of two steel joints with large dimensions is characterized. This characterization is made by using the component method and the finite element method whose results are compared with results of experimental tests carried out.This study allowed to conclude that the component method leads to a conservative estimate for the strength and stiffness of the joints. Furthermore, the finite element method can lead to a good estimate for the behaviour of the joints but for this the boundary conditions of test specimens shall be clearly defined.This study still allowed to conclude that the finite element method is a tool with so many potentialities that allow to a very rigorous characterization of the effective behaviour of the joints. However, its use for the design of joints has prohibitive costs in that it requires a lot of time to create and run models, but also know-how to define not only the materials models as well as the meshes.It is thus concluded that the component method is perfectly applicable to joints with large dimensions and is the most cost-effective method for use in the design.