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1
GUPTA, ARUN KUMAR. "DETERMINATION OF SEISMIC PARAMETER OF RCC TALL BUILDING USING SHEAR CORE , SHEAR WALL AND SHEAR CORE WITH OUTRIGGER." Thesis, DELHI TECHNOLOGICAL UNIVERSITY, 2021. http://dspace.dtu.ac.in:8080/jspui/handle/repository/18840.
Повний текст джерелаАнотація:
This report covers the detailed explanation about the determination of seismic parameter of
RCC tall building using shear core, shear wall and shear core with outrigger. Building are
subjected to various loads such as dead load, live load ,wind load and seismic load. Seismic
load has extreme adverse effect on building so it is necessary to perform seismic analysis This
paper describe about the response of building when it is subjected to seismic load , this
response can be shown by story drift and base shear. Seismic analysis has been performed on
(G+30) building which is located in zone 4 using ETABS software. Analysis has been
performed according to IS 1893 PART 1 (2016). This paper gives total rule to manual as wells
programming examination of seismic coefficient technique.
2
Roberts, Ryan (Ryan M. ). "Shear lag in truss core sandwich beams." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32935.
Повний текст джерелаАнотація:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (leaf 30).
An experimental study was conducted to investigate the possible influence of shear lag in the discrepancy between the theoretical and measured stiffness of truss core sandwich beams. In previous studies, the measured values of stiffness in loading have proven to be 50% of the theoretical stiffness during three point bending tests. To test the effect of shear lag on this phenomenon, the beams' dimensions were altered to decrease the presence of shear lag in a gradual manner so a trend could be observed. The experimental trails were carried out on three types of beams each with different diameters of truss material. Results show that this study has improved the accuracy of the measured results from previous studies with the two smallest truss diameter beams. Because the discrepancy between the theoretical and measured values is the greatest for the largest beams, (when the shear deflection has the least influence), it is concluded that shear lag is not responsible for the discrepancy between measured and theoretical stiffness.
by Ryan Roberts.
S.B.
3
Noury, Philippe. "Shear crack initiation and propagation in foam core sandwich structures." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326642.
Повний текст джерела
4
鄺君尚 and Jun-shang Kuang. "Elastic and elasto-plastic analysis of shear wall and core wall structures." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1988. http://hub.hku.hk/bib/B3123155X.
Повний текст джерела
5
梁少江 and Siu-kong Leung. "Analysis of shear/core wall structures using a linear moment beam-typeelement." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31213352.
Повний текст джерела
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Kuang, Jun-shang. "Elastic and elasto-plastic analysis of shear wall and core wall structures /." [Hong Kong] : University of Hong Kong, 1988. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12428565.
Повний текст джерела
7
Yun, Samuel. "Mechanical Analysis of a Detachment Shear Zone, Picacho Mountains Metamorphic Core Complex (AZ)." Thesis, University of Louisiana at Lafayette, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=10814249.
Повний текст джерелаАнотація:
On I-10 between Tuscon, AZ, and Phoenix, AZ, is the Picacho Mountains Metamorphic Core Complex (MCC). The Picacho Mountains MCC represents the northwest of the Greater Catalina MCC which includes Tortolita, Santa Catalina, and Rincon Mountains. To the immediate south of I-10 is Picacho Peak, an early Miocene andesitic volcanic center, and opposite of Picacho Peak are the granitic Picacho Mountains. The detachment shear zone (DSZ) is well exposed at Hill 2437. The mylonitic DSZ is separated into an upper, middle, and lower plate by two detachment faults. The DSZ is estimated to have undergone deformation at ~500?C based on recrystallized quartz microstructures and a previous thermochronologic study by previous graduate student Maxwell Schaper. We obtained an average flow stress of 43 ? 9 MPa using a quartz paleopiezometer by Stipp and Tullis (2003). Using a flow law by Hirth et al. (2001), we found strain rate values between 10-13 and 10-12 s-1. Grain size analysis indicates that quartz recrystallized grains have relatively moderate aspect ratio (1.55 < Rf < 1.87) which correlates to small amount of finite strain (1.13 < Rs < 1.33). Results from vorticity analysis based on the recrystallized quartz grain shape foliation method reveals that quartz was deformed under ~60% pure shear and ~40% simple shear (0.48 < Wm < 0.70, assuming plane strain), and the DSZ experienced ~18% of shortening perpendicular to mylonitic foliation, and up to ~22% of stretching parallel to the flow plane up. We found that despite high strain rate values and evidence of high strain rate (e.g. undulose extinction in quartz, chessboard structures, cataclasites, and possible pseudotachylytes), this is not reflected in the amount of finite strain recorded by the mylonitic DSZ.
8
Leung, Siu-kong. "Analysis of shear/core wall structures using a linear moment beam-type element /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B18155376.
Повний текст джерела
9
Lindwall, Caroline, and Jonas Wester. "Modelling Lateral Stability of Prefabricated Concrete Structures." Thesis, KTH, Betongbyggnad, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-188586.
Повний текст джерелаАнотація:
Stability calculations of prefabricated concrete structures with help of FEM-tools demand knowledge about how the elements are related to each other. This thesis concerns how joints between building elements affect the results when modelling prefabricated concrete structures, with demarcation to joints between hollow core (HC) slabs and between solid wall elements. The thesis also covers how the properties of the floor can be adjusted to account for the effects of the joints without modelling every single element. The work started by measuring the deflection of 10 HC-slabs jointed together and loaded in-plane acting as a deep beam, in a FE-model made with Robot™, from Autodesk®. The joints between the HC-elements were modelled either rigid or elastic, and the cross-section and the length of the HC-elements were varied. The linear elastic stiffness between the HC-elements was obtained from the literature as 0.05 (GN/m)/m. The results showed that a changed cross-section geometry gave greater differences in deformation than a changed length. The in-plane shear modulus was then adjusted for the HC-elements in the rigid cases until the same deflection was achieved as for the elastic cases. The result showed that the shear modulus in average for the different cross-section geometries and lengths had to be reduced with a factor of 0.1 to account for the joints. Based on the geometry of a castellated joint between prefabricated solid concrete walls, a calculation model was developed for its linear elastic stiffness. The result was a stiffness of 1.86 (GN/m)/m. To verify the calculated stiffness, a FE-model was developed consisting of a 30m high wall, loaded horizontally in-plane and with one or two vertical joints where the stiffness was applied. The deflection and the reaction forces were noted and the result from the calculated stiffness was compared to other stiffnesses and assessed reasonable. The reaction forces were shown to depend on the stiffness of the joint. The reduced in-plane shear modulus of the HC-elements and the calculated stiffness of the wall joints were then used in a FE-model of a 10-storey building stabilised by two units. The vertical reaction forces were analysed and the results showed 0.02 % difference in the reaction forces in the stabilising units when consideration of the joints between the HC-elements were taken into account and 0.09 % when the vertical joints in the shear wall were taken into account. The results for the wall joint differed from the results when only the wall was modelled. This was thought to be a result of that the floors counteract the shear deformations in the wall joints. The influence of the floor joints was not significant for the building considered in this thesis, but for buildings with non-continuous configuration of the stiffness in the shear walls the outcome may be another, in these cases the reduction factor may be useful.Vid stabilitetsberäkningar av prefabricerade betongstommar med hjälp av FEM-verktyg ställs krav på kunskap om hur elementen förhåller sig till varandra. Detta arbete berör hur fogar mellan byggnadselement påverkar modellering av prefabricerade betongstommar med avgränsning till fogar mellan håldäckselement och mellan solida väggelement. Arbetet berör även en studie i hur ett bjälklags egenskaper kan justeras så att fogarnas effekt kan tillvaratas utan att modellera varje enskilt håldäckselement. Arbetet inleddes med att utböjningen analyserades hos 10 st ihopskarvade håldäckselement, lastade i dess plan likt en hög balk, i en FE-modell skapad i programmet Robot™, från Autodesk®. Fogarna mellan håldäcken modellerades som antingen rigida eller elastiska och håldäckens tvärsnittsgeometri och längd varierades under testet. Den linjära styvheten mellan håldäcken togs från litteraturen som 0.05 (GN/m)/m. Resultatet visade att ändrad tvärsnittsgeometri gav större skillnader för deformationen än varierad längd på håldäcken. Håldäckens skjuvmodul justerades sedan i dess plan för de rigida testen tills dess att de uppnådde samma utböjning som de elastiska. Resultatet visade att skjuvmodulen behövdes reduceras med en faktor 0.1, i medeltal för de olika tvärsnittsgeometrierna och håldäckslängderna. Utefter geometrin på en fog med förtagningar mellan prefabricerade väggar togs en beräkningsmodell fram för den linjärelastiska styvheten i väggfogarna. Resultatet blev en styvhet på 1.86 (GN/m)/m. För att verifiera den beräknade styvheten togs en FE-modell fram bestående av en 30m hög vägg lastad horisontellt i dess plan med en eller två vertikala fogar där en linjär styvhet applicerades. Utböjningen samt reaktionskrafterna noterades, resultatet för den uträknade linjära styvheten jämfördes med andra styvheter och bedömdes utifrån detta vara rimlig. Reaktionskrafterna visade sig vara beroende av styvheten på fogen. Den sänkta skjuvmodulen för håldäcken och den beräknade linjära elasticiteten för väggarna användes sedan i en FE-modell av en 10-våningsbyggnad med två stabiliserande enheter där de vertikala reaktionskrafterna analyserades. Resultatet visade att endast 0.02 procentenheter skiljer reaktionskrafterna i de stabiliserande enheterna då hänsyn tas till fogarna mellan håldäcken och 0.09 procentenheter då hänsyn tas till fogarna mellan väggarna. Resultatet skiljer sig från när endast väggen modellerades, vilket tros bero på att bjälklaget hjälper till att motverka deformationer i väggfogarna. Fogen mellan bjälklagselementen tros kunna ha större inverkan på en byggnad med stabiliserande enheter som drastiskt ändrar styvhet från ett plan till ett annat, i dessa fall kan den framtagna reduktionsfaktorn vara av nytta.
10
Fiszman, Nicolas. "Study of the average shear velocity of the inner-core of the earth using isolation filters." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/52999.
Повний текст джерела
11
Vailhé, Christophe N. P. "Deformation mechanisms in B2 aluminides: shear faults and dislocation core structures in FeAl, NiAl, CoAl and FeNiAl." Diss., Virginia Tech, 1996. http://hdl.handle.net/10919/38075.
Повний текст джерела
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Vailhé, Christophe N. P. "Deformation mechanisms in B2 aluminides : shear faults and dislocation core structures in FeAl, NiAl, CoAl and FeNiAl /." This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-06062008-154448/.
Повний текст джерела
13
Asia, Winifred. "An in-vitro study of the physical properties of core build-up materials." University of the Western Cape, 2017. http://hdl.handle.net/11394/6307.
Повний текст джерелаАнотація:
Magister Chirurgiae Dentium - MChD (Prosthodontics)The aim of this study was to evaluate and compare the physical properties of two core build-up materials (ParaCore and CoreXflow) and compare this to conventional composite material (Filtek Supreme Plus and SDR Flow) used as core build-up material.
14
Cuenca, Asensio Estefanía. "ON SHEAR BEHAVIOR OF STRUCTURAL ELEMENTS MADE OF STEEL FIBER REINFORCED CONCRETE." Doctoral thesis, Universitat Politècnica de València, 2013. http://hdl.handle.net/10251/18326.
Повний текст джерелаАнотація:
Cuenca Asensio, E. (2012). ON SHEAR BEHAVIOR OF STRUCTURAL ELEMENTS MADE OF STEEL FIBER REINFORCED CONCRETE [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/18326Palancia
15
Mirza, Adeel R. "Evaluation of AISC Steel Coupling Beam Embedment Length in Composite Ordinary Shear Walls." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1543577095290297.
Повний текст джерела
16
Torres, Ivan Francisco Ruiz. "Efeito da deformação por cortante no cálculo de edifícios de andares múltiplos com núcleos estruturais." Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-13122017-154253/.
Повний текст джерелаАнотація:
O principal objetivo deste trabalho é realizar a análise estrutural de edifícios de andares múltiplos que apresentam núcleos resistentes, considerando a deformação pelo esforço cortante nos mesmos, bem como nos pilares. Para atingir esse objetivo, será preciso que o comportamento à flexão dos elementos verticais de contraventamento passe a ser regido pela teoria de barras de Timoshenko e não mais pela de Euler-Bernoulli. Foram então desenvolvidos algoritmos que, utilizando o Método dos Elementos Finitos (MEF), permitem calcular os fatores de forma de quaisquer seções transversais abertas de paredes delgadas pertencentes a núcleos estruturais, bem como a distribuição da tensão de cisalhamento na seção transversa em função do esforço cortante atuante. As alterações acima descritas foram feitas em um programa de análise de edifícios denominado CEASO 01, de autoria de MATIAS JR (1997). Embora esse programa realize análise não-linear geométrica, a consideração da deformação por cortante só foi implementada na análise linear. Apresentam-se, ao final, exemplos numéricos que permitem avaliar a influência da deformação pelo esforço cortante sobre os deslocamentos e esforços de núcleos resistentes e pilares.The main aim of this work is to perform structural analysis of multistory buildings with resistant cores, taking into account shear deformation in those elements, as well as in columns. To achieve this objective, the flexural behaviour of vertical elements must be governed by Timoshenko beam theory, rather than the Euler-Bernoulli theory. Procedures using the finite element method (FEM) were developped, which enable to evaluate shear correction factors of generic thin-walled open sections and shear stress distribution as a function of the shear resultant. Changes described above were made in a structural analysis program named CEASO 01, whose author is MATIAS JR (1997). Even though this program is able to perform nonlinear analysis, only in linear analysis the effect of shear deformation is taken into account. Numerical examples are provided, which enable to evaluate the influence of taking into account shear deformation on displacements and stress resultants of resistant cores and columns.
17
Kunwar, Sushil. "Comprehensive Evaluation of Composite Core Walls for Low-Seismic Force and Wind Load Applications." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613750905724949.
Повний текст джерела
18
Woods, Lisa Joy. "The significance of negative bending moments in the seismic performance of hollow-core flooring." Thesis, University of Canterbury. Civil and Natural Resources Engineering, 2008. http://hdl.handle.net/10092/2042.
Повний текст джерелаАнотація:
Hollow-core flooring units are designed as simply supported members. However, frequently in construction, continuity is established between the units and supporting structure by the addition of insitu topping concrete and steel reinforcement. This change in structural form can result in negative bending moments and axial forces being induced in the floor by seismic and other structural actions. Significant negative moments are induced by load combinations that include the effects of seismic forces due to vertical ground motion. The focus of this research was two failure mechanisms possible under these loading conditions, a flexural failure and a shear failure. Both failure mechanisms were investigated analytically and experimentally.
A brittle flexural failure was observed experimentally in a sub assembly test that contained starter bars and mesh reinforcement in the insitu topping concrete. The failure occurred at loads lower than those predicted using standard flexural theory. It appears that, due to the prestressing and low reinforcement ratio of the topping concrete, the assumption that plane sections remain plane is not appropriate for this situation. It is proposed that a strain concentration factor be introduced to account for the effects of tension stiffening. This factor improves the correlation between observed and predicted flexural strength.
The second failure mode investigated was a flexure shear failure in a negative moment zone. Flexural cracks reduce the shear strength of a reinforced concrete member. Analytical predictions suggest that some hollow-core floor details could be prone to this type of brittle failure. A flexure shear failure was not observed experimentally; however, this does not eliminate the possibility of this failure mode.
A summary of other failure mechanisms possible in hollow-core flooring is also presented. All failure modes should to be considered as part of establishing a hierarchy of failure in the design or retrofit of hollow-core floors.
19
Quezada, Eder, Yaneth Serrano, and Guillermo Huaco. "Dynamic Amplification Factor Proposal for Seismic Resistant Design of Tall Buildings with Rigid Core Structural System." Smart Innovation, Systems and Technologies, 2021. http://hdl.handle.net/10757/653773.
Повний текст джерелаАнотація:
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.Currently, there is an increase in the demand for tall buildings in the city of Lima. This research proposes to reduce the dynamic amplification factor through the seismic design of tall buildings based on the requirements of Peruvian code considering that they are regular in plan and height. Minimum base shear values according to the comparison of static seismic shear and dynamic shear from the spectral modal analysis were reviewed for cases of buildings larger than 120 m. The study of 28 reinforced concrete buildings was proposed, with different heights - varying from 24 to 36 floors, with different floor configurations, as well as the arrangement of the walls considering as a rigid core structural system. Additionally, the characteristics of the materials, the loads and combinations were defined. The responses of these buildings were determined by the response spectrum analysis (RSA) and then compared with those obtained by the lineal response history analysis (LRHA), for the last analysis, five Peruvian seismic records were used and scaled to 0.45 g. The seismic responses of the LRHA procedure were taken as a benchmark. The result of this study is the analysis and proposal of the C/R factor for high-rise buildings, as well as obtaining the base shear and drift verification. Minimum base shear values can be reduced for high or long-term buildings, being regular in plan and height.
Revisión por pares
20
Al, Ateah Ali H. "NUMERICAL STUDY OF MULTIPLE ROCKING SELF-CENTERINGROCKING CORE SYSTEMS WITH BUCKLING-RESTRAINED COLUMNSFOR MID-RISE BUILDINGS." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1511816354436547.
Повний текст джерела
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Naji, Behnam. "Flexural Analysis and Composite Behavior of Precast Concrete Sandwich Panel." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1355331734.
Повний текст джерела
22
Junior, Edgard Sousa. "Análise da interação entre núcleos estruturais e lajes em edifícios altos." Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-04042016-162358/.
Повний текст джерелаАнотація:
É apresentado um estudo sobre a análise de edifícios altos enrijecidos com núcleos estruturais utilizando-se processos discretos. A ligação do núcleo estrutural com as lajes do pavimento do edifício é o ponto principal deste estudo. As vigas, pilares e lajes são analisados utilizando-se o Método dos Elementos Finitos. Os núcleos estruturais, que no presente estudo podem ser de seção aberta ou semifechada, são analisados pela teoria de flexo-torção é levado em consideração o empanamento do elemento do núcleo, dessa forma aparece o esforço denominado bimomento. O empenamento do núcleo estrutural é transferido para as lajes, ocorrendo alteração em sua distribuição de esforços. Para o cálculo da estrutura do edifício como um todo é utilizada a técnica de subestruturação em que o edifício é dividido em subestruturas formadas por um determinado número de andares. Os resultados da forma de cálculo pesquisada são comparados com modelos já desenvolvidos por outros autores.This is a study about the analysis of tall buildings with shear/core walls using discrete processes. The joining of shear/core with slabs in tall buildings is the main subject of this work. The beams, columns and slabs are analyzed using the Finite Element Method. The building analysis is in 1st order. The shear/core walls, in this study, can present open or semi-closed cross section; they are analyzed by the theory of warping of beams of solid sections. In this theory we consider the warping of the core element, accounting for the bimoment. The warping of the core is transferred to the slabs, and the efforts in the slabs are altered. In order to calculate the building structure we are using the sub-structure technique, the building is divided in substructures created by a certain number of floors. The results of this research are compared with models developed by other authors.
23
Quezada, Ramos Eder Nel, Arone Yaneth Serrano, and Guillermo Huaco. "A comparative study of the seismic base shear force and story drift ratios using Time History and Modal Spectrum Analysis according to Peru Code E.030 and ASCE 7.16 on high-rise buildings." Institute of Electrical and Electronics Engineers Inc, 2020. http://hdl.handle.net/10757/656418.
Повний текст джерелаАнотація:
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.Since the last decade there is an important increase of high-rise buildings in Peru, especially in urban areas. Therefore, it is necessary to assess if the Peruvian Seismic Code is applicable for this type of buildings which have long natural periods as their main characteristic. The main objective of this article is to compare the results of the base shear and story drift ratios of Peruvian seismic design code E.030 with those of the ASCE 7-16 standard to the case of high-rise buildings, this due to the fact that there is limited information for tall buildings in Peru or comparison between national or international code for this type of structures. These high rise buildings have square and rectangular plan floors. Half of them have moment frames and reinforce concrete slab around the rigid core and the others have post-tensioned slab as their vertical load resisting system and central core walls with peripheral columns as the lateral force resisting system. Hence, the response spectrum analysis (RSA) is carried out for every case of the four tall buildings with different configurations using both seismic codes. Then results are compared with the linear response history analysis (LRHA) considering five Peruvian ground motions records, which were scaled to 0.45g PGA. It was verified that generally both the base shear and the interstory drifts calculated using ASCE7-16 are less than that obtained with the seismic code E.030.
24
Pinheiro, Gregory Lee. "Estudo da influência do preenchimento de alvéolos em lajes alveolares submetidas à força cortante." Universidade Federal de São Carlos, 2014. https://repositorio.ufscar.br/handle/ufscar/4696.
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The use of precast elements has become crescent in Brazil, due to the need of haste during production as well as while assembling the structures. Bearing in mind a quick assembly and the competitive price for this kind of frame, precast elements have been growing and spreading in this field throughout the country. There is something special about demanding hollow core slabs, in virtue of their own low weight, in face of the empty spaces generated by the hollows and a better use of materials because of pretension technique, making it economically feasible. The National Technical Code ABNT NBR 9062, which deals with precast concrete structures, shows no more specific criteria as far as hollow core slabs are concerned, but on the other hand the 2011 review in force to ABNT NBR 14861 which covers precast hollow core slabs brings about relevant aspects such as the method used to check the capacity of shear strength on precast hollow core slabs, both with and without concrete structural cover, and furthermore with and without hollow fillings. Considering the reduced amount of national research on this topic, this study aims to develop and perform techniques in different ways of filling the hollows and the slabs and how they behave when exposed to shear strength tests. As a consequence to the manufacturing process of such type of slab and the hollow- filling method, failure in the idealized filling, in virtue of each material own behavior and inappropriate technique are commonly found.
O emprego de elementos pré-fabricados tem se tornado crescente no Brasil, dado a necessidade de velocidade de produção e montagem de estruturas. Tendo em vista a rápida montagem e o preço competitivo deste tipo de estrutura, elementos prémoldados tem ganhado campo no mercado nacional. Há um destaque pela procura de lajes alveolares, devido ao seu baixo peso próprio, decorrente de vazios proporcionados pelos alvéolos e maior otimização dos materiais em virtude da aplicação da técnica de pré-tração, tornando-a economicamente viável. A Norma Técnica Nacional ABNT NBR 9062 que trata de estruturas pré-moldadas de concreto não apresenta critérios mais específicos para lajes alveolares, por outro lado a revisão em vigor de 2011 da ABNT NBR 14861 que aborda lajes alveolares préfabricadas traz aspectos relevantes tais como o método de verificação da resistência à força cortante de lajes alveolares com ou sem capeamento estrutural e com ou sem preenchimento de alvéolos. Tendo em vista o reduzido volume de pesquisas nacionais sobre o tema, esta pesquisa tem como objetivo fazer um estudo teórico-experimental das diferentes técnicas de preenchimento de alvéolos de lajes alveolares e o seu comportamento quando submetidas a ensaios de força cortante. Como consequência do processo de fabricação deste tipo de laje e do método de preenchimento dos alvéolos, falhas no preenchimento idealizado devido ao comportamento distinto dos materiais e técnicas inadequadas são comumente constatadas.
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Marquesi, Matheus Lorena Gonçalves. "Contribuição ao estudo dos mecanismos resistentes à força cortante em lajes alveolares protendidas." Universidade Federal de São Carlos, 2014. https://repositorio.ufscar.br/handle/ufscar/4697.
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Previous issue date: 2014-02-25In this work flexure shear and tension shear are studied. It is presented a literature review with emphasis on the major normative recommendations about the shear strength in elements without shear reinforcement. Concerning flexure shear capacity considerations are made about the tensile strength of high strength concrete by analysis of 39 experiments. This samples were collected in the literature and are presented herein. Furthermore, it is proposed to consider the variable influence of prestressing on the shear strength. With respect to tension shear, it is proposed the coefficient b, which seeks to improve the traditional models considering indirectly the influence of shear stresses in transmission length. 49 international experiments are analyzed to validate this coefficient and it is concluded that the modified models show significant improvements. Yet developed an experimental program were tested 15 hollow core slabs varying the distance between the edge of the slab and its nearest support. All failures were by tension shear. The transmission length established by NBR14861 was considered adequate for the tested slabs by correlation with tension shear test results.
Os mecanismos condicionantes à ruptura por força cortante em lajes alveolares são estudados: flexo-cortante e tração diagonal. Apresenta-se a revisão bibliográfica com ênfase nas recomendações dos principais códigos normativos acerca da resistência à força cortante em elementos sem armadura transversal. Quanto à flexo-cortante, considerações são feitas sobre a resistência à tração de concretos de alta resistência pela análise de 39 experimentos coletados na literatura e apresentados neste trabalho. Além disso, propõe-se a consideração da influência variável da protensão na resistência a força cortante. No tocante a tração diagonal, propõe-se o coeficiente b, que busca melhorar os modelos de cálculo tradicionais considerando de forma indireta a influência dos esforços cisalhantes devido à introdução da protensão na laje alveolar. São analisados 49 experimentos internacionais para a validação deste coeficiente e conclui-se que os modelos de cálculo modificados por este coeficiente apresentam melhoras significativas. Desenvolveu-se ainda um programa experimental em que foram ensaiadas 15 lajes alveolares variando a distância entre a extremidade da laje e seu apoio mais próximo. Todas as rupturas foram pelo mecanismo de tração diagonal. O comprimento de transferência de protensão estabelecido pela NBR14861 foi considerado adequado para as lajes ensaiadas pela correlação com os resultados dos ensaios de ruptura por força cortante.
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Bower, Owen J. "Analytical Investigation into the Effect of Axial Restraint on the Stiffness and Ductility of Diagonally Reinforced Concrete Coupling Beams." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1211065883.
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Periotto, Bruna Catoia. "Lajes alveolares protendidas: cisalhamento em região fissurada por flexão." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-20092011-111138/.
Повний текст джерелаАнотація:
Esta pesquisa teve como principal objetivo analisar o comportamento de lajes alveolares protendidas de uso corrente no Brasil (pequenas espessuras e alta protensão) quanto ao cisalhamento em região fissurada por ação do momento fletor, para diferentes situações: sem e com capa e com preenchimento parcial de alvéolos. Foi desenvolvido um estudo teórico com o emprego de equacionamentos analíticos disponíveis na literatura técnica, envolvendo as recomendações da norma brasileira NBR 6118:2003 (Projeto de Estruturas de Concreto), do ACI-318:2008 (Building code requirements for structural concrete) e da EN 1992-1-1 (2004) (Eurocode 2- Projeto de estruturas de betão Parte 1-1: Regras gerais e regras para edifícios). Foram feitas comparações com resultados experimentais obtidos a partir de inúmeros ensaios de lajes alveolares protendidas. As unidades ensaiadas nesta pesquisa foram disponibilizadas por quatro empresas brasileiras de intensa atividade no mercado, sendo analisadas as capacidades resistentes de diferentes tipos. Assim, foram realizados 96 ensaios, 31 para a determinação da capacidade resistente à flexão e 65, ao cisalhamento, sendo selecionados modelos de lajes com grande emprego no mercado brasileiro. A partir desses ensaios, foi possível entender melhor o comportamento das lajes alveolares protendidas produzidas no Brasil. Com as diversas análises, considerando os ensaios experimentais e um vasto estudo teórico quanto ao dimensionamento dessas lajes, verificou-se a adequabilidade de equações de diferentes normas. Assim, foi possível identificar o equacionamento que melhor representa o comportamento das peças produzidas no Brasil, considerando inclusive peculiaridades de comportamento, que apresentam diferenças constratantes com relação a unidades produzidas em outros países. A partir desses estudos, produziu-se um amplo memorial de cálculo, considerando as diversas tipologias de lajes estudadas, com o objetivo de contribuir de modo didático com os engenheiros de estrururas. Logo, com esta pesquisa, foi possível não somente melhorar o entendimento do comportamento de tais lajes alveolares, como também fornecer subsídios para a avaliação desses elementos, considerando as características específicas das lajes produzidas no Brasil e, assim, contribuir para a padronização do dimensionamento junto à norma brasileira NBR 14861 (Laje pré-fabricada - Painel alveolar de concreto protendido).This work had as major objective to analyze the behavior of Brazilian prestressed hollow core slabs - small thickness and high level of prestressing - considering shear in a cracked region due to bending moment, for different design situations: without concrete topping, with concrete topping and with filling the voids. A theoretical study was developed with the use of analytical equations available in the technical literature, involving the recommendations of the Brazilian code NBR 6118:2003 (Design of concrete structures), ACI-318: 2008 (Building code requirements for structural concrete) and EN 1992-1-1 (2004) (Eurocode 2: Design of concrete structures - Part 1-1: General rules and rules for buildings), comparing experimental results from many prestressed hollow core slabs tests. The slabs tested in this study were provided by four different Brazilian companies with intense activity in the market, and the resistant capacity of different typologies was analyzed. Thus 96 tests were made, 31 to determine the bending capacity and 64 for the determination of shear strength, and were selected slab models from the Brazilian market that are highly employed. From these tests, it was possible a better understanding of the prestressed hollow core slabs behavior produced in Brazil. With several analysis considering the experimental tests and an ample theoretical study about the design of these slabs, the adequacy of different codes equations were verified. Thus, it was possible to identify the equations that best represent the behavior of elements produced in Brazil, also considering the behaviour peculiarities of these slabs that have contrasting differences, if compared with units produced in other countries. From these studies it was produced a large design manual, considering the various types of studied slabs, aiming to contribute in a didactic way to the structural engineers. So, with this research, it was possible not only to improve comprehension of the behavior of such prestressed hollow core slabs, as well as provide information for evaluation of these elements, considering the specific characteristics of the slabs fabricated in Brazil and thus to contribute with the standardization of the design in the Brazilian code NBR 14861 (Prefabricated slab - Prestressed concrete hollow core panel).
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FORTNEY, PATRICK JOSEPH. "THE NEXT GENERATION OF COUPLING BEAMS." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1115837131.
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Pedrosa, Filho Celso de Freitas. "Influencia do reembasamento com resina composta na resistencia a extrusão de retentores intra-radiculares de fibra de vidro." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289716.
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Orientador: Luis Roberto Marcondes MartinsTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: Neste estudo avaliou-se a resistência ao cisalhamento por extrusão de pinos de fibra de vidro, reembasados ou não com compósito, cimentados com cimento resinoso em dentina intra-radicular, avaliando os segmentos cervical, médio e apical. Selecionaram-se 20 incisivos bovinos com dimensões semelhantes, removendo a porção coronária, padronizando o comprimento das raízes em 16 mm. Após, incluiu-se as raízes em resina acrílica, realizando tratamento endodôntico e, então o preparo dos espaços para os pinos, dividindoas, em seguida, aleatoriamente em dois grupos com dez amostras cada. Os elementos do grupo 1 receberam pinos de fibra de vidro somente cimentados, e do grupo 2 pinos de fibra de vidro reembasados com compósito e posteriormente cimentados. Ao término dos procedimentos de cimentação, realizou-se a secção dos segmentos radiculares, submetendo, então, os corpos-de-prova ao teste push-out em máquina de ensaios universal, através de ponta ativa cilíndrica com 1 mm de diâmetro, à velocidade de 0,5 mm/min, até extrusão do retentor. Obteve-se os seguintes valores médios de resistência de união, em MPa: grupo 1, terços cervical = 6,24 ± 2,68(b), médio = 4,27 ± 2,00(b) e apical = 4,46 ± 2,82(b); grupo 2, terços cervical = 11,83 ± 1,69(a), médio = 11,81 ± 3,86(a) e apical = 10,39 ± 2,44(a). Submeteram-se os valores à análise de variância e ao teste de Tukey com nível de significância de 5%, indicadas acima através de letras diferentes. Os pinos de fibra de vidro reembasados com compósito apresentaram valores estatisticamente superiores de união em todos os segmentos radiculares quando comparados com pinos somente cimentados. Observou-se também a ausência de diferença significativa entre os terços radiculares avaliados para cada grupo distintamente. Os resultados demonstraram que a técnica de reembasamento mostrou-se efetiva em melhorar a retenção do pino de fibra de vidro estudado
Abstract: This study evaluated the bond strength of fiber posts, relined or not with composite resin, luted with resinous cement to radicular dentin, evaluating cervical, median and apical root segments. Twenty bovine incisors, with similar dimensions, were selected and cut 16 mm from the apical limit. The roots were embedded in acrylic resin and the radicular canals were root treated and post space prepared with a depth of 9 mm. Samples were randomly assigned to two groups of ten roots each. Group 1 received glass fiber posts (Fibrekor) luted with dual-cure resin cement (RelyX ARC) in association with a bonding system (Adper Single Bond). In Group 2 the same type of posts were relined with composite (P-60) for further cementation with the same materials used in Group 1. After cementation procedures roots were sectioned transversally and three sections, from cervical, medium and apical thirds were obtained. Push-out test was performed in a universal testing machine with a 1 mm diameter steel rod at cross-head speed of 0,5 mm/min until post extrusion. Collected data was statistically analyzed by twoway ANOVA and Tukey HSD test (p<0,05). The measured retention strengths for cervical, medium and apical thirds were: Group 1, 6.24 ± 2.68(b), 4.27 ± 2.00(b) and 4.46 ± 2.82(b) ; Group 2, 11.83 ± 1.69(a), 11.81 ± 3.86(a) and 10.39 ± 2.44(a). Glass fiber composite relined posts presented statistically higher retention values in cervical, medium and apical thirds when compared to non-relined posts. Within each group, no differences were found among radicular thirds. The results indicate that the tested technique showed effective improvement of glass fiber post retention strength
Doutorado
Dentística
Doutor em Clínica Odontológica
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Hammerman, Mattias, and Robert Karlsson. "Analysis of undrained shear strength from drop-cone tests." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-93142.
Повний текст джерелаАнотація:
The Swedish Geotechnical Institute, SGI, has been given the assignment of mapping the risk of landslides in the area by the river Göta älv. Tests were made to determine the shear strength of soil on land and in the river. It has been shown that shear strength values evaluated with drop cone tests from points under the river are higher compared to other test methods although experience shows that the shear strength values from fall cone tests usually is slightly lower compared with those from other test methods. The soil under the river is more over consolidated then the surrounding soil because of years of erosion from the river. When evaluating undrained shear strength from CPT- and field vane shear tests, consideration to over consolidation is taken. SGI is now interested to look into if this needs to be done when evaluating undrained shear strength from fall cone tests as well. This thesis compares values from fall cone tests without correction for the over consolidation with values which is corrected to see if a correction is necessary. All data concerning the soils effective stress is necessary for calculating the over consolidation ratio and is evaluated manually. There is no set method to correct fall cone tests for the over consolidation so the existing formula used in the correction of field vane shear tests in over consolidated soils were used, both in its original form and with the exponent -0,15 adjusted. Own evaluations were made on the CPT- and field vane shear tests for comparisons with the results from the fall con tests. All processed data comes from SGI's own measurements. Results show that shear strength values from fall cone test and CPT field tests match better after corrections due to the over consolidation with the presented formula.Statens Geotekniska institut, SGI har haft i uppdrag att skredkartera Göta älvdalen. Man har gjort provtagningar på land och i älven för att bestämma skjuvhållfastheten i jorden. Det har visat sig att skjuvhållfasthetsvärdena utvärderade med fallkonförsök på provpunkter i älven är högre än de från övriga provmetoder vilket de erfarenhetsmässigt inte brukar vara. I älven där leran under årens lopp avlastats genom erodering är leran mer överkonsoliderad jämfört med omkringliggande lera. Vid utvärdering av skjuvhållfasthet från CPT- och vingförsök tas numera hänsyn till jordens överkonsolidering. SGI är nu intresserade av att undersöka om detta även behöver göras vid bestämning av skjuvhållfasthet från fallkonförsök. I detta examensarbete jämförs skjuvhållfasthetsvärden från fallkonförsök utan korrigering för överkonsolidering med korrigerade värden för att se om en korrigering är nödvändig. Alla värden på jordens effektivspänning, som behövs för att beräkna överkonsolideringsgraden är beräknade manuellt. Det finns ingen vedertagen metod för att korrigera fallkonförsök för överkonsolidering, så den befintliga formeln som används vid korrigering av vingsonderingar i överkonsoliderade jordar har prövats, både i sin ursprungliga form och med justeringar av exponenten -0,15. Till jämförelsen har egna utvärderingar utöver de av fallkonförsöken gjorts på CPT- och vingsonderingar. Alla behandlade data kommer från SGI:s egna mätningar. Resultaten visar att skjuvhållfasthetsvärden från fallkonförsök och CPT-sondering stämmer bättre överens efter en korrigering för överkonsolidering med tidigare nämnd formel.
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Borzacchiello, Nicola. "Shear behaviour of FRP RC beam." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
Знайти повний текст джерелаАнотація:
This thesis investigates the shear behaviour of reinforced concrete beams with FRP bars (Fibre Reinforced Polymers) as a substitute for steel bars. This means that both longitudinal and transverse reinforcement shall be in FRP. The main aim of this study shall be to compare the most recent worldwide regulations in force (based on the use of FRP) with an existing database compose of 205 samples. Correction of some standards shall be proposed, as well as personal modification of the Model Code 2010. The material’s properties shall be presented first, then the various shear crack mechanisms shall be described. Part of this work was carried out in the University of Sheffield’s laboratories, where the author was involved in a small part of experimental tests of local researchers. The result shall be included in the database. This document has been realized using L A TEX and only with free software.
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Greig, James William. "Estimating undrained shear strength of clay from cone penetration tests." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25076.
Повний текст джерелаАнотація:
This paper discusses several proposed methods for estimating undrained shear strength from cone penetration tests. This correlation has been studied in the past, however, most have focussed only on the cone bearing. In addition to discussing these traditional methods, this paper evaluates recently proposed methods of estimating Su from CPT pore pressure data.
The results of field vane and cone penetration tests from five lower mainland sites are presented in relation to the different proposed correlation techniques. The results show that there is no unique cone factor for estimating Su from CPT for all clays, however, a reasonable estimate of Su can be made by comparing the predictions from several of the proposed methods. With local correlations these techniques can be quite reliable. The results also show that the estimation of Su from CPT is influenced by various factors relating to: the choice of a reference Su, cone design, CPT test procedures and the soil characteristics. In particular, the estimation of Su from CPT is strongly influenced by such soil parameters as stress history, sensitivity and stiffness. Increases in OCR and sensitivity were reflected by increases in the traditional cone factors Nc and Nk.
The use of pore pressure data appears to be a promising means of estimating. Su from CPT. Expressions have been developed that predict excess pore pressures based on cavity expansion theory and attempt to include the effects of sensitivity, stress history and stiffness. In addition, comparisons between friction sleeve measurements and Su and a method for estimating sensitivity from friction ratios are presented. Lastly, recommended procedures for estimating Su from CPT are given.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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高學常 and Hok-sheung Go. "Lateral and torsional analysis of shear cores by semi-analytical formulation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1991. http://hub.hku.hk/bib/B31209725.
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Go, Hok-sheung. "Lateral and torsional analysis of shear cores by semi-analytical formulation /." [Hong Kong] : University of Hong Kong, 1991. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13009564.
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Gillespie, Donald G. (Donald Gardner). "Evaluating shear wave velocity and pore pressure data from the seismic cone penetration test." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30573.
Повний текст джерелаАнотація:
Recent developments in cone penetration testing have resulted in the addition of both pore pressure measurements and seismometers. The seismometers allow shear wave velocity testing to be performed at designated intervals. Both of these additions were researched to improve their application and interpretation.
The significant factors effecting the pore pressure generated during cone penetration tests are discussed. The importance of various factors is especially dependent upon permeability, strength, and stiffness. For all sands tested, pore pressures lower than static were recorded behind the tip and higher than static were recorded on the face of the cone. It is believed that the large compressive stresses on the cone face result in positive pore pressures. As the cone tip passes a soil element unloading and continued shearing generate pore pressures lower than static in all sands. The sign of this pore pressure (higher or lower than static) was therefore considered primarily a function of the test equipment.
Pore pressure response and the rate of dissipation of excess pore pressures were found useful in distinguishing fine granular soils and explaining soil stratigraphy. In cohesive soils the details of pore pressure measurement were found to be important only in stiff soils. Pore pressures at all measurement locations were found to increase with soil strength in soft to firm clays but may be negative of static in very stiff clays. Pore pressures behind the cone tip were often negative of static in stiff clays.
Measurement techniques were refined to improve the accuracy of downhole shear wave velocity measurements. Comparisons of downhole and crosshole measurements were made at three well documented sites validating the technique. At several sites it was found useful to consider the Gmax values determined from shear wave velocity and density to distinguish soil type. Gmax to cone resistance ratios were shown to vary systematically with cone resistance values in sands. A wide range in Gmax to cone resistance was observed in clays. The dependence of both cone penetration resistance and Gmax to increased stress level or overburden stress is discussed.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Keener, Kevin Michael. "Evaluation of four strength measurement devices : cone penetrometer, vane shear, modified vane shear, and hand vane in two Ohio soils." The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1298897218.
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Mjöberg, Mårten, and Axel Stenfors. "CPTu Configuration Impact on Evaluated Undrained Shear Strength." Thesis, KTH, Jord- och bergmekanik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279465.
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This thesis evaluates the commonly used geotechnical probing method CPTu, on how different probe configurations impact the resulting evaluated undrained shear strength in soft clay deposits, in comparison to each other and laboratory methods. This is done by performing field investigations on Lindefältet, Södermanlands län, Sweden. Comparison is done on the two Swedish manufacturers of CPTu probes, by different calibration limits, filter types and whether overloading the probe over the calibration limit affects the evaluated undrained shear strength registered. The main conclusions are that one of the manufacturers’ probes registers deviating results in one configuration, that calibration limit has a noticable impact on the results, and that overloading on the probe and filter choice has negliable impact on the results.I detta examensarbete utvärderas den vanligt förekommande geotekniska sonderingsmetoden CPTu, på hur olika konfigurationer av sonder påverkar den resulterande utvärderade odränerade skjuvhållfastheten i lösa leravlagringar, 9i jämförelse med varandra och med laboratoriemetoder. Detta är genomfört genom fältundersökningar på Lindefältet, Södermanlands län. Jämförelsen gjordes på de två svenska CPTu-tillverkarnas sonder. Detta är gjort med hänsyn till olika kalibreringar av konspetstryck, filtertyper, och huruvida sonden har varit överlastad påverkar den utvärderade skjuvhållfastheten som registreras. De huvudsakliga slutsatserna är att en av tillverkarnas sonder registerar udda värden i en konfiguration, att kalibreringar av konspetstryck har en märkbar påverkan på de resulterande värdena på utvärderade odränerade skjuvhållfastheten, samt att överlastning av sonder och val av filtertyp har liten till omärkbar påverkan på resultatet.
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Núñez, Pezo Eduardo Antonio. "Impact of shear in computing p-y curves for a RC pile." Tesis, Universidad de Chile, 2013. http://www.repositorio.uchile.cl/handle/2250/114479.
Повний текст джерелаАнотація:
Ingeniero CivilEstudios realizados por Stewart et al, 2007, y posteriormente por Lemnitzer et al, 2013, han mostrado que para una pila con restricción al giro en el cabezal (Fixed Head) los desplazamientos por esfuerzo de corte pueden llegar a contribuir en un 40% de los desplazamientos totales, a nivel de terreno, y sugieren que el efecto de corte influye en la determinación de curvas p y. De esta forma, se ha utilizado un modelo de interacción corte flexión para estimar el efecto del corte en la determinación de las curvas p y, modelo inicialmente propuesto por Massone et al, 2006, para el análisis de muros de H.A, extendiéndolo en este trabajo para el análisis de columnas. Dada la geometría de la pila, distintas versiones del modelo de interacción se han validado utilizando la respuesta global carga desplazamiento de ensayos de columnas circulares recopiladas de la base de datos de PEER, 2011, y de Kawashima Lab, 2011, estudiando la respuesta en términos de rigidez, capacidad máxima y desplazamiento al 10% de degradación de capacidad. Estos especímenes fueron seleccionados de forma de observar degradación por corte en la respuesta. Se ha encontrado buena correlación tanto en rigidez como en capacidad, teniendo valores de razón promedio entre el modelo y el ensayo de (V_mod⁄V_exp ) 0.91 para la capacidad máxima y de (K_mod⁄K_exp ) 1.3 para la rigidez, con coeficientes de variación de 0.09 y 0.18, respectivamente, usando el modelo de interacción con un perfil calibrado de deformaciones laterales o expansión (ε_x). Al estudiar la degradación, se ha observado buena correlación al utilizar una discretización en la dirección longitudinal con una razón diámetro largo del elemento (D⁄h_st ) igual a 2.0, obteniendo así un valor promedio de (δ_mod⁄δ_exp ) 0.86 con un coeficiente de variación de 0.38. El modelo de flexión, por su parte, entrega valores de (V_mod⁄V_exp ) igual a 1.1 y (K_mod⁄K_exp ) igual a 1.9. No se consideró el análisis de (δ_mod⁄δ_exp ) por no observar degradación en 6 de 10 casos a grandes deformaciones (δ_mod⁄δ_exp ≫2). Las curvas p y fueron determinadas para un ensayo de una pila Fixed Head, realizado por Stewart et al, 2007, utilizando un procedimiento de ajuste de la respuesta global de un modelo de flexión y a su vez de un modelo de interacción. Se utilizó la forma base de las curvas p y propuestas por API (1993) para una arcilla dura, como una respuesta trilineal. Los resultados muestran que para la curva p y ubicada en la superficie de terreno, la razón entre modelo de flexión e interacción es de (p_(u_Flex)⁄p_(u_inter) ) igual a 0.67 para la resistencia última y de (K_Flex⁄K_inter ) igual a 0.77 para la rigidez inicial. Los desplazamientos por corte contribuyen en un 35% de los desplazamientos totales, para un desplazamiento lateral de 3.0 in a nivel de terreno. Adicionalmente, se realizaron análisis de sensibilidad, en donde se determinó que el efecto de corte está concentrado entre la superficie de terreno y una profundidad de 2 diámetros (48 in) y además, se mostró que aumentando al doble la armadura transversal en esta zona se logra aumentar la capacidad en un 7%, para un desplazamiento de 3.0 in, y aumentar la ductilidad de la pila en un 50%. En este caso las deformaciones por esfuerzo de corte contribuyen en un 13% de los desplazamientos totales, para un desplazamiento lateral de 6.0 in, que es el punto en donde se observa degradación.
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Casey, Thomas J. "Shear wave data collection in mid America using an automated surface source during seismic cone testing." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/32804.
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Liao, Chung-Lon. "Applications of cone, vane and vane-cone to predict stress-strain behaviour of unsaturated cohesive soil." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=72788.
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Denison, Tracy Adam. "The effect of fluid shear stress on growth plate." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29603.
Повний текст джерелаАнотація:
Thesis (Ph.D)--Biomedical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Boyan, Barbara; Committee Co-Chair: Schwartz, Zvi; Committee Member: Bonewald, Lynda; Committee Member: Jo, Hanjoong; Committee Member: Sambanis, Athanassios. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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ElGendy, Mohammed. "Punching shear behaviour of slab-column edge connections reinforced with fibre-reinforced polymer (FRP) composite bars." Canadian Society of Civil Engineering, 2014. http://hdl.handle.net/1993/24092.
Повний текст джерелаАнотація:
The use of fibre reinforced polymer (FRP) composites as an alternate to steel has proved to be an effective solution to the corrosion problem. However, FRP bars have low axial and transverse stiffness compared to steel bars which results in a lower shear capacity of FRP reinforced concrete (RC) elements compared to steel-RC elements.
Flat plate systems are commonly used to take advantages of the absence of beams. They, however, are susceptible to punching shear failure where the column suddenly punches through the slab.
An experimental program was conducted to investigate the punching shear behaviour of slab-column edge connections. Nine isolated full-scale slab-column edge connections were constructed and tested to failure. One connection was reinforced with steel flexural reinforcement, six with GFRP flexural reinforcement and two with GFRP flexural and shear reinforcement. The parameters investigated were the flexural reinforcement type and ratio, the moment-to-shear ratio and the shear reinforcement spacing.
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Mandal, Anirban. "Computational Modeling of Non-Newtonian Fluid Flow in Simplex Atomizer." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1202997834.
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Kapoor, Hitesh. "Isogeometric Finite Element Code Development for Analysis of Composite Structures." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/50567.
Повний текст джерелаАнотація:
This research endeavor develops Isogeometric approach for analysis of composite structures and take advantage of higher order continuity, smoothness and variation diminishing property of Nurbs basis for stress analysis of composite and sandwich beams and plates. This research also computes stress concentration factor in a composite plate with a hole.Isogeometric nonlinear/linear finite element code is developed for static and dynamic analysis of laminated composite plates. Nurbs linear, quadratic, higher-order and k-refined elements are constructed using various refinement procedures and validated with numerical testing. Nurbs post-processor for in-plane and interlaminar stress calculation in laminated composite and sandwich plates is developed. Nurbs post-processor is found to be superior than regular finite element and in good agreement with the literature. Nurbs Isgoemetric analysis is used for stress analysis of laminated composite plate with open-hole. Stress concentration factor is computed along the hole edge and good agreement is obtained with the literature. Nurbs Isogeometric finite element code for free-vibration and linear dynamics analysis of laminated composite plates also obtain good agreement with the literature.
Main highlights of the research are newly developed 9 control point linear Nurbs element, k-refined and higher-order Nurbs elements in isogeometric framework. Nurbs elements remove shear-locking and hourglass problems in thin plates in context of first-order shear deformation theory without the additional step and compute better stresses than Lagrange finite element and higher order shear deformation theory for comparatively thick plates i.e. a/h = 4. Also, Nurbs Isogeometric analysis perform well for vibration and dynamic problems and for straight and curved edge problems.
Ph. D.
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Zreik, Diana Alexandre 1966. "Determination of the undrained shear strength of very soft cohesive soils by a new fall cone apparatus." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13399.
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Barra, Cortés Maximiliano Hernán. "Analysis of beams with transverse opening using a shear-flexure interaction model and validation with experimental data." Tesis, Universidad de Chile, 2015. http://repositorio.uchile.cl/handle/2250/136162.
Повний текст джерелаАнотація:
Ingeniero CivilUn modelo que combina las respuestas de corte y flexión fue desarrollado por Massone et al. (2006). Este modelo ha sido validado para muros esbeltos y muros cortos (Massone et al., 2009). El modelo fue adaptado para su uso en vigas simplemente apoyadas con ciertas particularidades, como fibras de acero en la mezcla de hormigón o la utilización de hormigón de auto consolidación (Galleguillos, 2010 y Gotschlich, 2011 respectivamente). El modelo de interacción corte-flexión fue adaptado para simular vigas de hormigón armado en cantiléver con una abertura rectangular en la dirección transversal horizontal al centro de su luz. El objetivo era el de validar el modelo para su uso en elementos de esta naturaleza, que son comunes en edificios modernos, en donde se busca aprovechar la altura completa de pisos. Las aberturas se utilizan para el paso de conductos y tuberías. Los resultados obtenidos mediante el modelo de interacción fueron comparados con resultados experimentales, descritos por Lemnitzer et al. (2013). La respuesta global predicha se acerca considerablemente a la respuesta experimental, mostrando curvas de carga desplazamiento razonables. Las limitaciones del modelo fueron evidentes al estimar la zona de falla del Espécimen 1, que presenta daño en su abertura. Otras discrepancias son la alta ductilidad que entrega el modelo analítico, retrasando la degradación por la contribución de corte, así como la alta rigidez inicial que presentan las simulaciones. La acumulación de daño por corte en ciertas zonas fue bien capturada mediante el modelo para los tres especímenes que fallaron en su interfaz con el bloque de reacción, pero no así la acumulación de daño por flexión. La máxima capacidad de los especímenes fue bien predicha, con discrepancias iguales o menores a un 10%. Una variación en la discretización inicial de las vigas junto a una baja en las resistencias de los elementos en el modelo permite inducir la falla en la zona de la abertura. Esta última discretización es recomendada para estudios a futuro.
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Liao, Tianfei. "Post processing of cone penetration data for assessing seismic ground hazards, with application to the New Madrid seismic zone." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-05042005-133640/.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2006.Mayne, Paul W., Committee Chair ; Goldsman, David, Committee Member ; Lai, James, Committee Member ; Rix, Glenn J., Committee Member ; Santamarina, J. Carlos, Committee Member.
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Feltre, Gabriela. "Estudo das alterações na microestrutura de partículas de amido de milho em processos de granulação." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/74/74133/tde-14052015-092222/.
Повний текст джерелаАнотація:
O amido de milho é uma importante fonte de energia para os seres humanos e é muito utilizado em preparos de diversos pratos. Os grânulos de amido possuem estrutura semicristalina que sofre degradação em elevadas temperaturas e com presença de água. Com o objetivo de alterar a microestrutura dos grânulos de amido de milho, principalmente quanto à sua temperatura de gelatinização, foram realizados processos de aglomeração de três diferentes métodos e avaliadas as modificações ocorridas. Todas as partículas produzidas passaram por análises de DSC, FT-IR, DRX e MEV. O trabalho foi divido em três diferentes estudos. No Estudo I, foi realizada a aglomeração do amido de milho com solução de alginato de sódio por \"high shear\" com posterior secagem em leito fluidizado. A partícula depois de seca teve 99,5% de amido em sua composição. Os resultados mostraram que houve aglomeração nos grânulos de amido de milho; porém, devido à baixa fração de alginato de sódio nas partículas, elas não apresentaram diferenças significativas quanto à sua temperatura de gelatinização, sua estrutura e suas ligações, quando comparadas ao amido nativo. No Estudo II, em que foi realizada a aglomeração dos grânulos de amido de milho com solução de alginato de sódio e cloreto de cálcio, por \"dripping\", foram obtidas partículas com frações de (0, 50, 60, 70, 80 e 90)% de amido. As modificações aconteceram à medida em que se aumentou a quantidade de alginato de sódio da partícula. As partículas com maiores frações de amido não apresentaram alterações significativas em sua microestrutura e temperatura de gelatinização, quando comparadas ao amido de milho nativo. As partículas com menores frações de amido, ou seja, maiores teores de alginato de sódio, apresentaram alterações em sua microestrutura e cristalinidade, além de maiores temperaturas de gelatinização. No Estudo III, foi realizada a aglomeração do amido de milho com quitosana por \"dripping\" em soluções de diferentes molaridades de de hidróxido de sódio (NaOH). Dentre as principais modificações observadas, destaca-se o aumento da temperatura de gelatinização, em partículas que foram precipitadas em soluções alcalinas de NaOH com molaridade de (0,10 e 0,12) M. Para as concentrações molares de (0,14, 0,16, 0,18 e 0,20) M, de NaOH, observou-se que parte dos grânulos de amido de milho foram solubilizados pela solução alcalina, e que as frações sólidas remanescentes apresentaram-se na forma de partículas precipitadas de amido-quitosana, com aparência transparente e amarelada. Os processos de aglomeração do amido de milho nativo pelos métodos \"high shear\" e \"dripping\", utilizando-se soluções de alginato de sódio e quitosana, podem resultar em partículas resistentes à gelatinização, devido à atribuição de uma barreira física por estes ligantes, após as etapas de secagem. O aumento da concentração de alginato resultou em um aumento da temperatura de gelatinização, produzindo partículas de amido resistentes à degradação térmica. Adicionalmente, observou-se que o uso de soluções alcalinas diluídas de NaOH, também permitiu a produção de partículas resistentes à degradação térmica, por meio da precipitação da quitosana. O método \"dripping\" permitiu a produção de partículas com elevadas concentração de alginato ou quitosana, e foi o método mais indicado para a produção de partículas de amido resistentes à degradação térmica. As partículas aglomeradas pelo método \"high shear\" tiveram concentração de ligante (alginato de sódio) limitada a 0,5%, e não resultaram em partículas resistentes à degradação térmica.Corn Starch is an important source of energy for humans and is widely used in food preparations. Starch granules exhibit a semicrystalline structure which undergoes degradation at high temperatures and the presence of water. In order to change the microstructure in corn starch granules, especially regarding its gelatinization temperature, three diferente methods of agglomeration processes were performed and changes of starch particles were studied. Every produced particle were analysed by DSC, FT-IR, XRD and SEM. The work was divided into three different studies. In Study I, agglomeration of corn starch was carried out with sodium alginate solution by \"high shear\" with subsequent fluidized bed drying. The dry contained was 99,5% starch in its composition. The results showed that the cornstarch granules agglomerated; however, due to the low fraction of sodium alginate in the particles, they showed no significant differences in gelatinization temperature, its structure and interactions when compared to native starch. In Study II, was performed the agglomeration of corn starch granules with sodium alginate solution and calcium chloride by dripping method and particles obtained contained (0, 50, 60, 70, 80 and 90)% (w/w) of starch. Modifications occurred with increasing the amount of sodium alginate in the particle. Particles with higher starch fractions showed no significant changes in its microstructure and gelatinization temperature, compared to the native corn starch. Particles with lower starch fraction, and higher concentrations of sodium alginate, showed changes in their microstructure and crystallinity, and higher gelatinization temperatures. In Study III, the agglomeration of cornstarch with chitosan by dripping in sodium hydroxide (NaOH) solutions of different molarities was evaluated. Among the main changes increases on the gelatinization temperature of particles precipitated in alkaline NaOH solutions with molarity (0,10 and 0,12) M was observed. For the molar concentrations (0,14, 0,16, 0,18 and 0,20) M NaOH, it was observed that some of granules corn starch were solubilised by the alkaline solution and the remaining solid fraction presented the form of precipitated particles of starch-chitosan with transparent and yellowish appearance. The native corn starch agglomeration processes by the methods \"high shear\" and \"dripping\", using solutions of sodium alginate and chitosan, can result in particles resistant to gelatinization due to the formation of a physical barrier of these ligands, after drying steps. Increasing the alginate concentration resulted in increase in the gelatinization temperature of starch, resulting in particles resistant to thermal degradation. Additionally, it was observed that the use of dilute alkaline solutions of NaOH allowed the production of thermal degradation resistant particles through precipitation of chitosan. The \"dripping\" method enabled the production of particles with higher concentrations of alginate or chitosan, and was the most suitable method for the production of starch particles resistant to thermal degradation. The particles agglomerated by \"high shear\" had binder concentration (sodium alginate) limited to 0,5%, and didi not result in particles resistant to thermal degradation.
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Costa, Dorival Pereira Borges da [UNESP]. "Características da carne de novilhos Nelore alimentados com caroço de algodão." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/104085.
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Universidade Estadual Paulista (UNESP)
Objetivou-se avaliar o efeito da inclusão de diferentes níveis (0; 14,35; 27,51 e 34,09%) de caroço de algodão na dieta sobre a composição centesimal, maciez, cor e oxidação lipídica da carne de novilhos Nelore. Foram utilizados 36 novilhos não-castrados (peso vivo médio inicial de 333,50 kg e 20 meses de idade), os quais permaneceram por 94 dias confinados em baias com três animais. O delineamento foi o inteiramente casualizado com quatro tratamentos e nove repetições. Não houve diferença entre os tratamentos para o teor de umidade, proteína e cinzas. Entretanto o aumento dos níveis de caroço de algodão reduziu linearmente o percentual de gordura intramuscular. Os valores da força de cisalhamento, oxidação lipídica, cor da carne e cor da gordura foram semelhantes entre os tratamentos.
The objective of this study was to determine the effect of inclusion of whole cottonseed at different levels (0, 14.35, 27.51 and 34.09) in the diet on meat centesimal composition, tenderness, color and lipid oxidation of Nellore steers. Thirtysix steers (average initial body weight of 333.50 kg and aged 20 months) were housed during 94 days in pens with three animals each. A completely randomized design with four treatments and nine replications was used. No difference between treatments was observed concerning moisture, protein and ash contents. However, increasing levels of whole cottonseed caused a reduction in intramuscular fat. The values of shear force, lipid oxidation, meat color and fat color were similar between treatments.
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McGillivray, Alexander Vamie. "Enhanced Integration of Shear Wave Velocity Profiling in Direct-Push Site Characterization Systems." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19714.
Повний текст джерелаАнотація:
Enhanced Integration of Shear Wave Velocity Profiling in Direct-Push Site Characterization Systems
Alexander V. McGillivray
370 Pages
Directed by Dr. Paul W. Mayne
Shear wave velocity (VS) is a fundamental property of soils directly related to the shear stiffness at small-strains. Therefore, VS should be a routine measurement made during everyday site characterization. There are several lab and field methods for measuring VS, but the seismic piezocone penetration test (SCPTu) and the seismic dilatometer test (SDMT) are the most efficient means for profiling the small-strain stiffness in addition to evaluating large-strain strength, as well as providing evaluations of the geostratigraphy, stress state, and permeability, all within a single sounding.
Although the CPT and DMT have been in use for over three decades in the USA, they are only recently becoming commonplace on small-, medium-, and large-size projects as more organizations begin to realize their benefits. Regrettably, the SCPTu and the SDMT are lagging slightly behind their non-seismic counterparts in popularity, in part because the geophysics component of the tests has not been updated during the 25 years since the tests were envisioned. The VS measurement component is inefficient and not cost effective for routine use. The purpose of this research is to remove the barriers to seismic testing during direct-push site characterization with SCPTu and SDMT.
A continuous-push seismic system has been developed to improve the integration of VS measurements with SCPTu and SDMT, allowing VS to be measured during penetration without stopping the progress of the probe. A new type of portable automated seismic source, given the name RotoSeis, was created to generate repeated hammer strikes at regularly spaced time intervals. A true-interval biaxial seismic probe and an automated data acquisition system were also developed to capture the shear waves. By not limiting VS measurement to pauses in penetration during rod breaks, it is possible to make overlapping VS interval measurements. This new method, termed frequent-interval, increases the depth resolution of the VS profile to be more compatible with the depth intervals of the near-continuous non-seismic measurements of the SCPTu and the SDMT.