Dissertations / Theses on the topic 'Flexural loading'
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NAKAMURA, Hikaru, Naoshi UEDA, Minoru KUNIEDA, and Choonghyun KANG. "AUTOGENOUS HEALING PROPERTIES OF CONCRETE UNDER FLEXURAL LOADING." 日本コンクリート工学会, 2011. http://hdl.handle.net/2237/20958.
Full textChung, Chu Fung. "Flexural strengthening of beams with FRP under various loading configurations /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202004%20CHUNG.
Full textIncludes bibliographical references (leaves 138-142). Also available in electronic version. Access restricted to campus users.
Moawad, Mohamed Abdalla Mohamed Mohamed. "Flexural behavior of NSM FRP strenthened reinforced concrete beams under sustained loading." Doctoral thesis, Universitat de Girona, 2020. http://hdl.handle.net/10803/670950.
Full textEl objetivo principal de este trabajo es estudiar la resistencia a la flexión residual y a largo plazo de las vigas HA reforzadas con NSM con tiras de CFRP cuando se someten a cargas sostenidas. Este trabajo involucró veintiocho vigas RC divididas en dos series, A y B, con dos lotes de hormigón de diferente resistencia a la compresión. En cada serie, algunas de las vigas se reforzaron con tiras de CFRP utilizando la técnica de refuerzo NSM y las otras no se reforzaron. La serie A se dividió en dos grupos, Al y A2, mientras que la serie B se dividió en tres grupos, Bl, B2 y B3. Las vigas del primer grupo de cada serie se probaron a la edad de 55 días para determinar el comportamiento de flexión a corto plazo de las vigas. Otros grupos fueron sometidos a pruebas a largo plazo con diferentes secuencias
Rahman, S. M. Hasanur. "Flexural behavior of GFRP-reinforced concrete continuous beams." American Society of Civil Engineers, 2016. http://hdl.handle.net/1993/31905.
Full textFebruary 2017
Styles, Millicent, and milli styles@anu edu au. "Characterisation of the flexural behaviour of Aluminium Foam Sandwich Structures." The Australian National University. Faculty of Engineering and Information Technology, 2008. http://thesis.anu.edu.au./public/adt-ANU20080813.170807.
Full textStirling, Bradley James. "Flexural Behavior of Interlocking Compressed Earth Block Shear Walls Subjected to In-Plane Loading." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/593.
Full textWilson, Dean James. "Crustal structure of the Cape Verde Swell : insights into the flexural response of the lithosphere to loading." Thesis, Durham University, 2011. http://etheses.dur.ac.uk/3230/.
Full textVarghese, Joseph. "Effect of dynamic flexural loading on the durability and failure site of solder Interconnects in printed wiring assemblies." College Park, Md.: University of Maryland, 2007. http://hdl.handle.net/1903/7698.
Full textThesis research directed by: Dept. of Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Gao, Tian. "Direct Strength Method for the Flexural Design of Through-Fastened Metal Building Roof and Wall Systems under Wind Uplift or Suction." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/28553.
Full textPh. D.
Stuhlinger, Martin Ernst. "The influence of mixing ratio on the fatigue behaviour of fibre reinforced polymers." University of the Western Cape, 2013. http://hdl.handle.net/11394/5041.
Full textStatement of the problem: Fibre reinforcement of polymethyl methacrylate (PMMA) denture base material is known to improve the strength, as well as the fatigue behavior, of the material. The powder liquid (P/L) ratio of PMMA is often changed to modify the handling properties of the material. Little is known about the effect of this deviation from manufacturer’s guidelines on the fatigue behaviour of the fibre reinforced product. Purpose: This study compared the flexural strength (FS) of PMMA reinforced with glass fibre using different P/L ratios, before and after cyclic loading. Methods and materials: Three groups, with 50 glass fibre reinforced (everStick nonimpregnated fibers) heat-cured PMMA resin (Vertex Rapid Simplified) specimens each, were prepared using a custom-made template (dimensions 10x9x50mm). Each group had a different P/L ratio: the control group (100%) had the manufacturer’s recommended ratio; the 90% and 80% groups had reduced P/L ratios (by weight).Twenty five specimens from each group were subjected to a 3-point bending compression test using a universal testing machine. The remaining 25 specimens from each group were subjected to cyclic loading (104 cycles) before compression testing. The (FS) was calculated using the highest force (Fmax) before specimen failure. Flexural strength was calculated using the equation: FS=3WL/2bd2. Within each group, median FS values before and after cyclic loading were compared by means of a non-parametric analysis of variance. The Aligned Ranks Transform method was used for the analysis. Statistical significance was set at p=0.05. Results: The Fmax (N) of the control (100%), 90% and 80% groups fatigued and unfatigued were 100%: 1665 (fat), 1465 (unfat); 90%: 1679 (fat), 1548 (unfat) and 80%: 1585 (fat), 1467 (unfit) respectively. There was no significant interaction between Mix ratio and Fatigue state, and the 80% mix had a significantly higher mean than either the 90% or 100% mix (with differences of about 0.3 units for both). The Fatigued state had a higher mean than the Un- fatigued state by about 6.0 units. Using FS (MPa) it was found that the fatigued 80% mix specimens had the highest value. The FS MPa of the control (100%), 90% and 80% groups fatigued and un-fatigued were 64.3, 60.6; 66.9, 65.6 and 70.2, 69.3 respectively. The fact that fatiguing strengthened the specimens merits further research. When observing the broken specimens it was found that there was a complete debonding of the fibres and the PMMA. Conclusion and clinical relevance: a) Fibre: The benefit of using glass fibre bundles to reinforce prostheses fabricated using heat cured PMMA is questionable due to problems with bonding between the fibre bundles and the heat cured PMMA resin. b) Fatiguing: An average person chews 107 times during a 3 year period. A limited period of average masticatory forces should not have a detrimental effect on prostheses made from heat cured PMMA resin. c) Mix ratio: Within the normal parameters of laboratory techniques the mix ratio of PMMA resin had no significance on the fracture resistance of the prostheses. Due to the high cost of the fibres used for the reinforcement and the limited success and insignificant results achieved in this study, this researcher cannot recommend using Stickbond or Stick fibers for the reinforcement of dentures made with heat cured PMMA resin.
Mohamed, Ahmed Abdeldayem. "Behavior, strength and flexural stiffness of circular concrete columns reinforced with FRP bars and spirals/hoops under eccentric loading." Thèse, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/11406.
Full textLa détérioration des structures en béton armé avec des barres d’armature d’acier peut être observée quotidiennement dans les régions à climat agressif. Le renforcement interne en polymères renforcés de fibres (PRF) a démontré sa faisabilité grâce à différents éléments structuraux en génie civil. Les lignes directrices actuelles pour les structures en béton armé de PRF en Amérique du Nord et en Europe n'ont pas encore gérées les sections soumises à des efforts axiaux excentrique, en raison du manque de recherches et d'expériences. Cette recherche permet d’augmenter la base de données expérimentales ainsi établir des analyses approfondies et des recommandations de conception pour les colonnes circulaires en béton armé complètement renforcées de PRF (barres et spirales). Des grandeur-nature colonnes ont été testées sous charge monotone avec différents niveaux d'excentricité. Les variables de test comprenaient le rapport excentricité / diamètre (e/D) ; le type de renfort (PRFV et PRFC comparativement à l’acier); la résistance du béton en compression; le taux d’armature longitudinal et transversal; et la configuration de l’armature de confinement. Tous les échantillons mesuraient 305 mm de diamètre et 1500 mm de hauteur. Les résultats des tests ont indiqué que les spécimens renforcés avec des PRF de verre ou des PRF de carbone atteignaient leur résistance maximale sans endommager les barres d’armature. Des deux types de renforcement, les spécimens de PRFCCFRP se comportaient de manière très similaire à leurs homologues en acier et atteignaient presque les mêmes résistances axiales. Cependant, les spécimens avec renforcement en PRFV ont présenté une rigidité réduite et des forces axiales nominales inférieures à celles de leurs homologues en acier ou en PRFC. Le mode de rupture des spécimens de PRFC et de PRFV a été dominé par l’écrasement du béton à de faibles niveaux d'excentricité (rapports e/D de 8,2% et 16,4%). Les résultats ont révélé que les barres de PRFV ont développé des niveaux élevés de déformations et de contraintes sur les faces en compression et en tension et, par conséquent, les spécimens de PRFVC pourraient supporter une charge axiale constante après la résistance ultime pendant un certain temps jusqu'à la limite de la rupture en compression du béton du noyau à des niveaux supérieurs d'excentricité (rapport e/D de 8,2% et 16,4%), ce qui contribue à retarder la dégradation. À ces niveaux, une rupture en tension a été initiée dans les spécimens de PRFV résultant à de grandes déformations axiales et latérales et des fissures du côté de la face en tension jusqu'à ce que la rupture en compression du béton. La rupture des spécimens de PRFC à des niveaux supérieurs d'excentricité (rapport e/D de 8,2% et 16,4%) a été caractérisé comme étant en compression du béton dans laquelle il s'est déroulé de manière moins fragile. D'autre part, cette recherche comprenait également différentes études pour analyser les résultats des tests, évaluer l'efficacité des barres d'armature et fournir des recommandations pour l'analyse et la conception. Il a donc été indiqué que les capacités axiales et de flexion des spécimens en PRF testées pourraient être raisonnablement prédites en utilisant une analyse en section plane, en utilisant les paramètres du bloc de contrainte rectangulaire équivalent (BCRE) donnés par l'ACI 440.1R-15 ou la CSA S806- 12. Toutes les prédictions ont sous-estimé la résistance réelle avec des niveaux de variabilité conservateur entre 1,05 et 1,25 pour les spécimens de PRFC et entre 1,20 et 1,40 pour les spécimens de PRFC. Ces niveaux ont été nettement réduits à des limites critiques dans les spécimens avec des bétons à haute résistance. Un examen approfondi a été effectué sur les paramètres du BCRE disponibles dans les normes et les directives de conception actuelles en acier et en PRF. Les expressions modifiées du BCRE fournies dans ACI 440.1R-15 et CSA S806-12 ont été développées. Les résultats indiquent une bonne corrélation entre les valeurs de résistance prédites et mesurées avec des niveaux accrus de conservatisme. La contribution de la résistance à la compression du renforcement en PRF a été soigneusement examinée et discutée. Le taux d’armature minimum de PRFV et de PRFC pour éviter la rupture de l'armature ont été largement examinés. Enfin, la rigidité en flexion (EI) des spécimens testés a été déterminée de manière analytique et comparée aux expressions disponibles dans la littérature en utilisant les réponses expérimentales et analytiques M-ψ. Les expressions modifiées de la rigidité en flexion EI apportées dans l’ACI 440.1R ont été développées et validées.
Andreou, Eftychia. "Performance evaluation of RC flexural elements strengthened by advanced composites." Thesis, University of South Wales, 2002. https://pure.southwales.ac.uk/en/studentthesis/performance-evaluation-of-rc-flexural-elements-strengthened-by-advanced-composites(f441fa99-6428-46c2-8053-8e362546044c).html.
Full textRegmi, Bagale Bibek Regmi. "Fiber Reinforced Polymer Strengthening of Steel Beams– A Numerical and Analytical Study." University of Toledo / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1575821093025102.
Full textSyed, Shah Taqiuddin Q. "An Alternative Strengthening Technique using a Combination of FRP Sheets and Rods to Improve Flexural Performance of Continuous RC Slabs." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1469151846.
Full textAjaxon, Ingrid. "Can Bone Void Fillers Carry Load? : Behaviour of Calcium Phosphate Cements Under Different Loading Scenarios." Doctoral thesis, Uppsala universitet, Tillämpad materialvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-316656.
Full textSaloustros, Savvas. "Tracking localized cracks in the computational analysis of masonry structures." Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/461714.
Full textLos métodos numéricos son decisivos en la ingeniería para la conservación de estructuras de mampostería existentes y el diseño de estructuras nuevas. Entre ellos, los métodos macro-mecánicos de elementos finitos, basados en el concepto de fisuras distribuidas, son habitualmente los preferidos como opción asequible para el análisis de grandes estructuras de mampostería. Sin embargo, suelen resultar en a una representación poco realista del daño, distribuido en grandes áreas de la estructura, lo que impide la correcta interpretación del patrón de daño. Además, esta metodología presenta una patología más crítica, la dependencia de la malla, que influye notablemente en las predicciones de seguridad y estabilidad. Para superar estas limitaciones, esta tesis propone una nueva herramienta numérica basada en el enriquecimiento del clásico enfoque de fisuras distribuidas con un algoritmo de trazado local. El objetivo de este modelo de daño localizado es el análisis no-lineal de las estructuras de mampostería de manera realista y eficiente con una representación mejora-da de fisuras. El comportamiento no lineal de la mampostería se simula a través de la adopción de un modelo de mecánica de daño continuo con dos índices de daño, permitiendo la diferenciación entre las respuestas mecánicas de tensión y compresión de la mampostería. En este contexto, se propone e implementa una nueva formulación explícita para la evolución de deformaciones irreversibles. Se derivan dos nuevas expresiones para la regularización del ablandamiento de tracción y compresión según el ancho de banda de la fisura, garantizan-do la objetividad del modelo de daño al respecto del tamaño de la malla. La simulación del comportamiento estructural de las estructuras de mampostería en condiciones de carga y contorno generales precisa de algunos desarrollos en el contexto de los algoritmos locales de trazado. Con este objetivo, se presenta la mejora de los algoritmos locales de trazado con nuevos procedimientos que posibilitan la simulación de fisuración múltiple, arbitraria e secante bajo cargas monótonas y cíclicas. Además, se investiga el efecto de diferentes criterios de propagación de fisuras y se aborda la selección entre más de un plano de falla posible. El modelo de daño localizado propuesto se valida mediante la simulación de una serie de ejemplos estructurales. Éstos van desde pruebas a pequeña escala en probetas de hormigón, con pocas fisuras dominantes, hasta estructuras de mampostería de mediana y gran escala con fisuración múltiple de tracción, de cortante y de flexión. Los análisis se comparan con los resultados analíticos, experimentales y numéricos obtenidos con métodos alternativos disponibles en la literatura. El modelo de daño localizado mejora en gran medida la independencia de la malla del clásico método de fisuras distribuidas y reproduce patrones de daño y mecanismos de colapso de una manera eficiente y realista
Malan, Andreas Dawid. "Critical normal traffic loading for flexure of bridges according to TMH7." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80013.
Full textENGLISH ABSTRACT: Different types of live loading due to traffic may act on bridges. The focus of this study is on normal traffic loading according to the South African specification of TMH7. Heavy vehicles are not included in normal traffic loading. TMH7 represents the code of practice for the design of highway bridges and culverts in South Africa. The aim of the study is to provide an insight into the flexural analysis of skew bridges, under the effects of normal traffic loading. The need for the study arose since the specification of TMH7 does not explicitly specify application patterns for normal traffic loading. Only the intensity of normal traffic loading is specified and it should be applied to yield the most adverse effects. For these reasons, a set of so-called standard application patterns are investigated and developed through the course of this study. The envelope of the values from the standard application patterns are compared to the most adverse application pattern for flexural effects in certain design regions of the bridge deck. Flexure, as in the context of this study, translates into the bending and twisting of the bridge deck under loads. A number of numerical experiments are performed for typical single span and multi-span continuous carriageways, where the standard application patterns are compared to the most adverse application patterns. The results from the numerical experiments are documented and compared as the angle of skew of the bridge deck increases in plan-view. For this purpose, the development of effective and specialized software was necessary. It was found that the set of standard application patterns can be used as a preliminary approximation for the most adverse effects of normal traffic loading, for specific flexural resultants in certain design regions of a bridge deck. However, for a large number of secondary flexural effects, the set of standard application patterns did not represent a good approximation for the most adverse values.
AFRIKAANSE OPSOMMING: Verskillende tipes lewendige belasting, as gevolg van verkeer, kan op brûe inwerk. Die fokus van die studie is op normale verkeers-belasting volgens die Suid-Afrikaanse spesifikasie van TMH7. Swaar-voertuie word nie ingesluit by normale verkeers-belasting nie. TMH7 verteenwoordig die kode vir die ontwerp van padbrûe en duikers in Suid-Afrika. Die doel van die studie is om insig te verskaf in die buig-analise van skewe brûe, as gevolg van die werking van normale verkeers-belasting. Die rede vir hierdie studie ontstaan aangesien die spesifikasie van TMH7 nie eksplisiet aanwendingspatrone vir normale verkeers-belasting voorskryf nie. Slegs die intensiteit van normale verkeersbelasting word voorgeskryf en dit moet aangewend word om die negatiefste effekte te verkry. Vir hierdie redes word 'n versameling van sogenaamde standaard aanwendings-patrone deur die loop van die studie ondersoek en ontwikkel. Die omhullings-kurwe van die waardes wat deur die standaard patrone gelewer word, word vergelyk met die waarde van die aanwendings-patroon wat die negatiefste buig-effek in sekere ontwerp-areas van die brugdek veroorsaak. Buig-effekte, soos van toepassing op hierdie studie, verwys na buig en wring van die brugdek as gevolg van belastings. 'n Aantal numeriese eksperimente, vir enkel-span sowel as multi-span deurlopende brugdekke, word uitgevoer en die standaard aanwendings-patrone word vergelyk met die aanwendings-patrone wat die negatiefste waardes lewer. Die resultate van die numeriese eksperimente word gedokumenteer en vergelyk soos die hoek van skeefheid van die brugdek in plan-aansig toeneem. Vir hierdie doel is die ontwikkeling van effektiewe en gespesialiseerde sagteware dus nodig. Daar is gevind dat die standaard aanwendings-patrone, vir spesifieke buig-resultante in sekere ontwerp-areas van die brugdek, as 'n voorlopige benadering vir die negatiefste effekte van normale verkeers-belasting gebruik kan word. Dit was egter verder gevind dat vir 'n groot aantal sekondêre buig-effkte, die versameling standaard aanwendings-patrone nie as 'n goeie benadering vir die negatiefste waardes dien nie.
Dow, Douglas Donald. "Finite Element and Experimental Analyses of Hybrid Joints Subjected to Fully Reversed Flexure Fatigue Loading." Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/DowDD2008.pdf.
Full textMoschetti, Lorenzo. "Parametric Sensitivity Study of Shear-Flexure Interaction Modeling for Reinforced Concrete Structural Walls under Cyclic Loading." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
Find full textChen, Jie. "The Influence of Lithospheric Flexure Induced by Volcano Loading on Neogene Basin Evolution in McMurdo Sound, West Antarctica." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1448967436.
Full textMoharrami, Gargari Mohammadreza. "Development of Novel Computational Simulation Tools to Capture the Hysteretic Response and Failure of Reinforced Concrete Structures under Seismic Loads." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/71864.
Full textPh. D.
Býčková, Klára. "Návrh mostu přes řeku." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240018.
Full textWu, Zhenhua. "Behavior of high-strength concrete members under pure flexure and axial-flexural loading." 2006. http://www.lib.ncsu.edu/theses/available/etd-12122006-101746/unrestricted/etd.pdf.
Full textWijaya, Tanri, and 陳維安. "Flexural Deformation Capacity of RC Shear Wall under Earthquake Loading." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/52853019362566745224.
Full text國立臺灣大學
土木工程學研究所
101
Reinforced concrete shear walls are commonly used to resist the actions imposed on buildings due to earthquake loading. To resist such actions, properly proportioned and detailed slender walls are designed to yield in flexure, and to undergo large flexural deformations without loss of lateral load capacity. ACI 318-11 uses displacement-based design to ensure that the shear wall will have adequate deformation capacity. The basis of the approach is to use displacement as the primary design parameter to relate overall system response to wall cross section behavior. Recent earthquake reconnaissance in Chile and New Zealand gave shocking results for buildings that use a shear wall system. The result indicates that many of these buildings did not have adequate deformation capacity. The typical damage that was found, includes crushing/spalling of concrete, buckling of vertical reinforcement, and global wall buckling. Based on these observations, some changes in the ACI 318-11 will be made related to design and detailing of shear wall for the next ACI series, ACI 318-14. A prototype building which incorporates with two different shear wall cross-sections (rectangular and T-shaped) were chosen to investigate this ACI 318 code change. Design procedures are presented by including the shear capacity design recommended by NEHRP (2011). In addition, the use of high-strength material in the slender walls design was also observed in this study.
陳展裕. "Flexural Behavior of High-Performance Concrete Beams Under Cyclic Loading." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/46879211567945737325.
Full textHuang, Chien-Hao, and 黃建豪. "Flexural Behavior of Reinforced Lightweight Aggregate Concrete Beams under Cyclic Loading." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/30402280703652552714.
Full text國立中興大學
土木工程學系
91
The flexural behavior of reinforced lightweight aggregate concrete beam (R.L.C.) under cyclic loading is investigated in this study. The results are compared to corresponding reinforced concrete beam (R.C.). A total of 44 beam specimens were made. The parameters included concrete type, concrete strength, reinforcement ratio, spacing of shear reinforcement and section size. The test results show that R.L.C. beams have same or less ductility than R.C. beams. For specimens of reinforcement ratio smaller than 2.88%. Both R.L.C. and R.C. beams. increase of concrete strength will increase the ductility. For specimens of reinforcement ratio smaller than ρmax . Both at lower and higher concrete strength level, the decaying of strength and stiffness of R.L.C. beams appear milder than those of R.C. beams. By increase of concrete strength. The energy dissipation capacity of R.L.C. beams were obviously increased. When specimens were tend to compression fractured. The decaying of strength and stiffness of R.L.C. beams are similar or poor than those of R.C. beams. The energy dissipation capacity of R.L.C. beams are also similar or poor than those of R.C. beams. Different spacing of shear reinforcement have no obviously effect to the beams.
Styles, Millicent. "Characterisation of the flexural behaviour of Aluminium Foam Sandwich Structures." Phd thesis, 2008. http://hdl.handle.net/1885/48205.
Full text孫文昌. "Flexural behavior of reinforced concrete columns with high strength shear reinforcment under cyclic loading." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/06680269663037423839.
Full text國立中興大學
土木工程學系
87
The purpose of this study is to investigate the flexural behavior of reinforced concrete columns with high strength shear reinforcement under cyclic lateral load. A total of fourteen column specimens were made in this study. The size of specimens was 300mm×300mm×4500mm . The variables included were concrete strength、level of axial load 、 strength of transverse reinforcement and volume of transverse reinforcement . The results showed that ultimate strengths predicted by ACI Code were conservative. Columns under higher axial load exhibited less strength﹐ductility﹐stiffness and capability of energy dissipation .With same amount of transverse reinforcement , columns contained high strength shear reinforcement showed better ductility . When designed by ACI 318-95 equation (21-4), due to larger spacing , columns with high strength shear reinforcement showed less ductility in this study.
ZHUANG, SHI-ZI, and 莊世滋. "The relationships between the shifted of neutral axis under flexural loading and bentwood quality." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/17497960733173303535.
Full textRijo, Inês Costa. "Effect of chlorhexidine loading on the flexural strength of acrylic reline resins after thermal ageing." Master's thesis, 2018. http://hdl.handle.net/10451/35458.
Full textObjectives: The aim of this study was to evaluate the influence of the concentration of chlorhexidine (CHX) on the flexural strength of three reline acrylic resins, Kooliner, Ufi Gel Hard and Probase Cold, after undergoing a thermal ageing process. Methods: Distinct proportions of CHX were selected for loading each reline resin. Kooliner had four groups (1%, 2.5%, 5%, 7.5% CHX), Ufi Gel Hard had five groups (1%, 2.5%, 5%, 7.5%, 10% CHX) and Probase Cold had three groups (1%, 2.5%, 5% CHX). Every material had also a control group (0% CHX). Specimens with 64x10x3.3mm were submitted to a thermocycling procedure consisting of 1000 cycles of thermal fluctuations between 5ºC and 55ºC. Afterwards they were tested for flexural strength values using a three point bending device. Results were submitted to nonparametric tests according to the Kruskal-Wallis method, followed by multiple comparisons using Mann-Whitney tests with Bonferroni corrections, being considered the 5% level of significance (α=0.05). Results: Regarding Kooliner and Ufi Gel Hard specimens, there were no statistical significant differences on flexural strength values among different CHX groups (p>0.05). Results for Probase Cold specimens showed that 5% CHX group had a lower flexural strength value compared to the control group (p= 0.033). Conclusions: The proportions of 1%, 2.5%, 5% and 7.5% CHX for Kooliner, 1%, 2.5%, 5%, 7.5% and 10% CHX for Ufi Gel Hard and 1% and 2.5% CHX for Probase Cold do not affect the flexural strength values of the acrylic resins after a thermal ageing process equivalent to one month in the oral cavity.
Chen, Da-Ming, and 陳大明. "Flexural Behavior of Reinforced Concrete Columns with Welded Wire Fabric as Shear Reinforcement under Cyclic Loading." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/02358440076759929188.
Full text國立中興大學
土木工程學系
85
Abstract The purpose of this study is to investigate the flexural behaviorof concrete columns with welded wire fabric as shear reinforcement under constant axial load and cyclic lateral load . A total of ten column specimens were made in this study . The size of specimens was300mm×300mm×4500mm . The variables included were concrete strength、loading type、amount of transverse reinforcement、type of transversereinforcement、level of axial load and arrangement of transverse reinforcement . The results showed that strengths predicted by ACI Code were conservative . Cyclic loading on column would not reduce the maximumstrength but would reduce the ductility tremendously . Flexural strength、 ductility、crack control、strength and stiffness degradation of columns with welded wire fabric were about the same as columns withconventional transverse reinforcement . Capability of energy dissipationof columns with WWF was higher than that of conventional columns .WWFcan be adopted in concrete columns due to its construction ease .
Wu, Wen Ching, and 吳文欽. "Flexural Behavior of Reinforced Concrete Beams with Welded Wire Fabric as Shear Reinforcement under Cyclic Loading." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/98739789868980856486.
Full text國立中興大學
土木工程學系
84
Abstract The purpose of this study is to investigate the flexural behavior of reinforced concrete beams with welded wire fabric as shear reinforcement under cyclic loading. Atotal of fourteen beam specimens were made. Twelve contained welded wire fabric as shear reinforcement while the other two contained conventional shear reinforcement. The parameters included concrete strength, shear span to depth ratio, spacing of shear reinforcement, ratio of positive steel to negative steel, amount oftension reinforcement and loading history。 The results show that beams with welded wire fabric have less ductility than beams with conventional shear reinforcement. Beams with WWF have better crack control than those with conventional shear reinforcement. Beams with WWF showed faster deterioration than those with conventional shear reinforcement in strength and stiffness. Increase of amount of shear reinforcement and negative steel will increase the energy dissipation capacity。
Ngowi, Joseph Vincent. "Stability of Dry-Stack Masonry." Thesis, 2006. http://hdl.handle.net/10539/1557.
Full textThis thesis presents the findings on empirical study of dry-stack masonry. Dry-stack masonry refers to a method of building masonry walls, where most of the masonry units are laid without mortar in the joints. Of late (since mid eighties) in modern construction, dry-stacking or mortarless technology is increasingly becoming popular because of its advantages. The construction industry is acknowledging the need to accelerate the masonry construction process, as the traditional method is labour intensive and hence slower due to the presence of a large number of mortar joints. Early attempts were made to increase the size of masonry units (block instead of brick), thereby reducing the number of mortar joints, wherein the use of bedding mortar imposed constraints on the number of courses to be constructed in a day. Elimination of bedding mortar accelerates construction; thereby reducing cost, variation due to workmanship and generally small pool of skilled labour is required in dry stacking. Dry-stack masonry is a relatively new technology not yet regulated in the code of practice and therefore very limited information on the structural behaviour of the masonry is available. This project is based on the investigation of the HYDRAFORM dry-stack system, which utilises compressed soil-cement interlocking, blocks. The system is now widely used in Africa, Asia and South America. The main objective of the project was to establish through physical testing the capacity of the system to resist lateral load (e.g. wind load), vertical load and dynamic load such as earthquake loading. In the first phase of the project investigations were conducted under static loading where series of full-scale wall panels were constructed in the laboratory and tested under lateral loading, and others were tested under vertical loading to establish the mode of failure and load capacity of the system. Series of control tests were also conducted by testing series of wallettes to establish failure mechanism of the units and to establish the flexural strength of the system. Finally the test results were used for modelling, where load prediction models for the system under vertical loading and under lateral loading were developed. The theoretical load prediction models were tested against the test results and show good agreement. After the load capacity was established the next step in the study was to further improve the system for increased capacity particularly under dynamic loading. The normal Hydraform system was modified by introducing a conduit, which allows introduction of reinforcements. Series of dry-stack seismic systems were constructed and initially tested under static lateral loading to establish the lateral load capacity. The second Phase of the project was to investigate the structural behaviour and performance of the Hydraform system under seismic loading. A shaking table of 20 tonnes payload, (4m x 4m) in plan was designed and fabricated. A full-scale plain dry-stack masonry house was constructed on the shaking table and subjected to seismic base motions. The shaking table test was performed using sine wave signals excitations starting from low to very severe intensity. A conventional masonry test structure of similar parameters was also constructed on the table and tested in a similar manner for comparison. The tests were conducted using a frequency range of 1Hz to 12Hz and the specimens were monitored for peak accelerations and displacements. For both specimens the initial base motion was 0.05g. The study established the mode of failure of the system; the structural weak points of unreinforced dry-stack masonry, the general structural response of the system under seismic condition and the failure load. The plain dry-stack masonry failed at 0.3g and the conventional masonry failed at 0.6g. Finally recommendations for further strengthening of system to improve its lateral capacity were proposed.
Rossi, Mariana. "Flat Slabs with Different Longitudinal Reinforcement Ratios Under Horizontal Cyclic Loading." Master's thesis, 2021. http://hdl.handle.net/10362/118272.
Full textA presente dissertação estuda o comportamento de lajes fungiformes submetidas a carga vertical constante e carregamento horizontal cíclico, sendo a continuação de trabalhos realizados anteriormente no Departamento de Engenharia Civil da FCT/UNL. O principal objetivo deste trabalho é estudar a influência da variação da taxa de reforço longitudinal na resposta sísmica de lajes fungiformes. Assim, três modelos de lajes fungiformes com variação da taxa de armadura longitudinal foram fabricados e testados, dois com a mesma taxa de !=0,64% e outro com !=1,34%. Um dos modelos com baixa taxa de armadura longitudinal foi reforçado com reforço específico ao punçoamento. Todas as lajes possuíam as mesmas dimensões de 4,15 × 1,85 × 0,15 m3 e razão entre a carga vertical e a resistência ao punçoamento aproximadamente igual a 55%. Para uma análise mais completa, os resultados obtidos foram comparados com outros dois modelos testados anteriormente na FCT/UNL. Estas duas lajes possuíam uma taxa intermédia de reforço longitudinal (!=0,96%), uma sem armadura específica de punçoamento e a outra contendo “shear studs”. Os resultados mostraram que a redução da taxa de armadura longitudinal resultou num comportamento mais dúctil das lajes e numa capacidade maior de deslocamentos horizontais. A utilização da taxa mais elevada de armadura longitudinal laje melhorou a capacidade máxima de momentos não balanceados, mas também fez com que a estrutura tivesse uma rotura mais frágil. Como esperado, o modelo com “studs” suportou os maiores “drifts” e acabou não rompendo durante o ensaio, devido a ter sido atingido o limite do sistema de ensaio.
YE, ZHENG-JI, and 葉正吉. "Flexural vibrations of an annular plate under partial edge loadings." Thesis, 1986. http://ndltd.ncl.edu.tw/handle/09334878481138100454.
Full textCosta, João Manuel Magalhães Coelho Lima da. "Efeito do carregamento cíclico e da pré-fendilhação do betão no comportamento de lajes de betão armado reforçadas à flexão com laminados de CFRP inseridos." Master's thesis, 2015. http://hdl.handle.net/1822/40692.
Full textA presente dissertação aborda a investigação efetuada no âmbito do comportamento de lajes de betão armado reforçadas à flexão com a técnica da inserção (técnica NSM) de laminados de CFRP (Polímeros Reforçados com Fibras de Carbono) em entalhes efetuados no betão de recobrimento. Neste contexto, é estudado o efeito da pré-fendilhação do betão e do carregamento cíclico no comportamento à rotura de lajes de betão armado reforçadas à flexão com laminados de CFRP inseridos. Este trabalho é iniciado com a revisão bibliográfica, onde é apresentado o estado atual de conhecimento relativamente à utilização de materiais compósitos de CFRP no reforço à flexão de estruturas de betão armado no âmbito da temática da presente dissertação. De seguida, é apresentado o programa experimental no qual foi avaliado o efeito da pré-fendilhação e do carregamento cíclico no comportamento à rotura de lajes de betão armado reforçadas à flexão com laminados de CFRP inseridos. Foram analisados dois níveis de dano (pré-fendilhação) e dois níveis de carregamento cíclico. O comportamento à rotura das lajes pré-fendilhadas e reforçadas à flexão, com laminados de CFRP inseridos é comparado com o de uma laje semelhante, com a diferença de esta não ter sido pré-fendilhada. O comportamento à rotura das lajes reforçadas à flexão com laminados de CFRP inseridos e sujeitas a carregamento cíclico é comparado com o de uma laje semelhante, com a diferença de esta não ter sido submetida a carregamento cíclico. Por fim, são apresentadas as conclusões gerais obtidas com a realização desta dissertação, sendo posteriormente indicadas perspetivas de desenvolvimento futuro.
The current dissertation deals with the reasearch carried out on the behavior of reinforced concrete (RC) slabs flexural strengthened with CFRP (Carbon Fiber Reinforced Polymer) laminates according to the NSM (Near Surface Mounted) technique, which is based on introducing CFRP laminates into slits opened on the concrete of the slabs. Therefore, this work aims to study the effect of pre-cracking and cyclic loading on the behavior until failure of RC slabs flexural strengthened with NSM CFRP laminates. This work starts with the literature review about the current knowledge on the use of composite materials, such as CFRP, for the flexural strengthening of RC structures. Afterwards, the experimental program carried out on this work is described, which purpose is to evaluate the effect of pre-cracking and cyclic loading on the behavior until failure of RC slabs flexural strengthened with NSM CFRP laminates. It were analyzed two levels of damage (pre-cracking) and two levels of cyclic loading. The behavior until failure of pre-cracked RC slabs flexural strengthened with NSM CFRP laminates is compared with similar RC slab without pre-cracks before the CFRP application. The behavior until failure of RC slabs flexural strengthened with NSM CFRP laminates and subsequently subjected to a cyclic loading is compared with similar RC slab without cyclic loading. Finally, the most relevant conclusions obtained in this research are presented and the prospects for future developments are indicated.
Fundação para a Ciência e Tecnologia (FCT) - Projeto FCOMP-01-0124-FEDER-014844;
FEDER;
COMPETE.
Kuo, Shang-Hsun, and 郭尚勳. "A study on the strain of flexural wall and the dynamic characteristics of the soil behind flexural wall near the river during cyclic loadings." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/51232409544309252745.
Full text國立高雄應用科技大學
土木工程與防災科技研究所
92
The main objective in this research is focused on the dynamic characteristics of the soil behind the flexural wall during earthquake. Moreover the mechanism of lateral spreading of the soil was also discussed when the decrease of the lateral pressure is happened due to the wall movement. The experimental shaking table(2m×2m), on which a sand tank(1.8m×0.9m×1.45m) wsa placed, was used in the article. To record soil behavior during shaking, earth pressure transducers, LVDTs and accelerometers are prepared in the suitable locations within the tank. Both of flexibility wall and relative density of the backfill soil were considered respectively in experiment. Results of shaking table showed that the lateral displacement of the wall decreases with increasing wall thickness and the relative density of the backfill. To simulate experimental results, the proper model was also developed in this study. The outcome of model is approximately close to the findings in the laboratory. The dynamic lateral earth pressure curve is less regular due to the wall movement. Noted that it has low and high area for medium dense or dense backfill sand. The dynamic earth pressure results of experiments are different with those calculated from M-O method, because of outside movement of the wall. The results in stress-strain diagram revealed that the shear strain becomes less when the position is near bottom, but the shear stress of the bottom is higher than that of the top.
Aghabozorgi, Pegah. "Numerical Analysis of Concrete Elements Reinforced with GFRP Bars under Concentric and Eccentric Loadings and Four-point Bending." Master's thesis, 2019. http://hdl.handle.net/10316/98952.
Full textGlass Fiber Reinforced Polymer (GFRP) bars with significant corrosion resistance lead to an improvement in the performance of concrete structures and a significant reduction in costs. High ratio of tensile strength to weight, non conductive, and non-magnetic properties are other features of GFRP bars. Recent international design standards, such as ACI 440.1R-15 do not recommend including FRP reinforcement in compression, so they replace them by concrete in calculations. The purpose of this study was to investigate the effect of concentric and excentric axial loading on the axial capacity and ductility of GFRP reinforced concrete columns compared to steel reinforced concrete columns, comparison of flexural capacity of GFRP reinforced concrete beams with steel reinforced concrete beams, and also the effect of compressive bars on the bending capacity and ductility of GFRP reinforced concrete beams. In this study, concrete beams and columns were modeled using finite element software ,ABAQUS. Experimental data from previous studies were used as a criterion for numerical investigations and the model results were validated using the available experimental data. The results demonstrated that the average load carrying capacity of GFRP reinforced concrete columns is about 93.5 percent of steel reinforced concrete columns. GFRP reinforced concrete columns under concentric loading have greater load carrying capacity than GFRP reinforced concrete columns under eccentric loading which is more significant for steel reinforced concrete columns. The average flexural strength of steel reinforced concrete beam was about 90% of GFRP reinforced concrete beam. Also, the ductility of GFRP concrete beam specimens was greater than that for the steel beam specimen. Using GFRP compression reinforcement resulted in higher energy absorption and ultimately higher ductility of the GFRP concrete beams. Also, the results showed that GFRP compression reinforcement does not significantly increase the flexural strength of beams.
Mertol, Halit Cenan. "Behavior of high-strength concrete members subjected to combined flexure and axial compression loadings." 2006. http://www.lib.ncsu.edu/theses/available/etd-10242006-153208/unrestricted/etd.pdf.
Full textWang, Wen-Shin, and 王文士. "Characterization of The Flexure Behavior of Carbon Fiber Reinforced Thick Laminates Under Static and Dynamic Loadings." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/60752352729313875979.
Full textDeng, Yun-Feng, and 鄧雲峰. "The Developments of Flexure Hinge Based Stack-Type 5 DOF Nanometer-Scale Stage for a Heavy-Loading Machining Process and a New Nano-Contouring Measurement Technique." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/nz8h9d.
Full text國立虎尾科技大學
動力機械工程研究所
92
The main research of this paper can be divided into two respects, the first is that development of flexure hinge based stack-type 5 DOF micro-stage for a heavy-loading machining process; the second is that development of a new nano-contouring measurement technique. In semiconductor manufacturing facility, the ability to etch the minimum line width of IC process depends on the positioning resolution of the fine motion stage. The construction of 5 DOF micro-stages in this paper is to complete assembly using the characteristic of distortion of flexible ware and provide high accuracy positioning in conjunction with the piezoelectric actuators. A 5 DOF micro-stage were designed, fabricated, and tested. For the validity of the derived theoretical model, the results of the theory and experiment are all examined. The comparison of the results by theory and experiment shows good agreement. The performance of the micro-stage has 52.76μm travel along the x-axis, 5l.79μm ravel along the y-axis, 12.08μm travel along the z-axis and lnm resolution, and 185μrad along θx-axis, and 277μrad along θy-axis, and resonance frequency of l.25kHz. The micro-stage also can support 12 kilograms to move. As with measurement system, there kinds of contouring measurement systems that can reach nano-level accuracy and be built by means of there different kinds of lens group placing methods are formulated in this paper. The resolution of the measurement is 1nm.