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Showing 1 to 5 of 5 (0.026 seconds)Spelling suggestions: "subject:"[een] DUCTILITY FACTOR"" "subject:"[enn] DUCTILITY FACTOR""
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[en] UNIFORMLY PROBABLE DESIGN RESPONSE SPECTRUM FOR INELASTIC SECONDARY SYSTEMS / [pt] ESPECTRO DE RESPOSTA DE PROJETO UNIFORMEMENTE PROVÁVEL PARA SISTEMAS SECUNDÁRIOS INELÁSTICOSREGINA AUGUSTA CAMPOS SAMPAIO 15 December 2003 (has links)
[pt] Estuda-se a consideração de comportamento inelástico do
material na geração de espectros de resposta de projeto.
Para tanto, trabalha-se sobre um sistema secundário
simplificado acoplado a um pórtico de cinco andares com
características dinâmicas ajustadas para modelar um sistema
principal real, de uma usina nuclear. Faz-se um estudo
paramétrico sobre estes sistemas acoplados onde são
variados os parâmetros: fator de escoamento, a intensidade
da excitação e o nível de amortecimento. É proposto um
fator de dutilidade global formulado em termos de trabalho
externo realizado sobre o sistema secundário. São obtidos
espectros de dutilidade e de resposta. A análise de tais
espectros fornece informações sobre o desempenho do sistema
secundário e seus suportes e conclui por fatores de
transposição entre os espectros elástico e inelástico.
Propõe-se metodologia para obtenção de espectros de
resposta elásticos e inelásticos que levam em conta o
acoplamento entre os sistemas principal e secundário, o
movimento relativo dos suportes e o compromisso
probabilístico entre as ordenadas do espectro e a
sismicidade da região expressa em termos de uma função
densidade de espectro de potência objetivo para a
aceleração do terreno. Um exemplo de obtenção de espectros
de resposta acoplada de projeto uniformemente provável
inelástico é apresentado. / [en] The authors concern includes two main points in the subject
of design response spectra generation for secondary systems
in nuclear power plant structures: the consideration of
inelastic behavior in the secondary systems materials and
the production of uniformly probable design response
spectra. One works with a previously developed secondary
system model attached to primary structure model tuned to
the frequency range of a nuclear power plant building.
A global ductility factor is formulated relating the
plastic to the overall work done by the seismic external
forces on the secondary system. This factor together with a
particular definition of the yielding factor allows one to
determine elastic to inelastic spectrum transpose factors.
A methodology is proposed to generate uniformly probable
coupled response spectra for multiply supported inelastic
secondary systems. The seismic excitation is prescribed by
a target power spectrum density function of the ground
acceleration and an internal pressure condition is added to
the seismic action. Examples illustrate the application of
this proposed methodology.
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Elasto-Plastic Dynamic Analysis Of Coupled Shear WallsEl-Shafee, Osama January 1976 (has links)
<p> A method for tlie dynamic analysis· of planar coupled shear walls subjected to ground motions is developed herein. The method is capable of application to nonuniform coupled shear walls resting on flexible foundations. The possibility-of development of yield hinges at the ends of the connecting beams is included in the analysis . Also P-& Effect is incorporated in the stiffness of the structure. </p>
<p> The method is based on the transfer matrix technique in combination with the continuum method. A step-by-step integration approach is used in solving the equation of motion. The response to a number of earthquake records are obtained. The effect of the rotational ductility factor of connecting beams is studied. </p> / Thesis / Master of Engineering (MEngr)
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[en] EFFECTS OF THE INTERNAL PRESSURE AND TEMPERATURE VARIATIONS ON SEISMIC RESPONSE SPECTRA OF TUBULAR SYSTEMS / [pt] A PRESSÃO INTERNA E A VARIAÇÃO DE TEMPERATURA NOS SISTEMAS DE TUBULAÇÃO E OS ESPECTROS DE RESPOSTA DE PROJETO PARA CARGAS SÍSMICASJAIR JOSE DOS SANTOS GOMES 11 July 2005 (has links)
[pt] A análise de estruturas de sistemas secundários sujeitos a
cargas sísmicas é um
assunto em aberto e especial no projeto de instalações
industriais. Dois pontos
particulares atraem a atenção dos especialistas no esforço
a caminho de um projeto
mais realista, abrangente e econômico: a interação das
propriedades dinâmicas entre os
sistemas principal e secundário e a quantidade de
dutilidade do sistema secundário que
pode ou deveria ser considerada no projeto. Está muito
evidente nesse estágio que a
decisão do projetista tem de ser bem assessorada porque
dependendo das circunstâncias
os resultados finais podem mostrar muitas surpresas. O
contexto das experiências
nesse assunto, na PUC-Rio, inclui uma série de
iniciativas. Entre elas, se pode dar
especial menção às seguintes: o estudo e proposta de uma
metodologia para
desenvolver um espectro de resposta acoplada (Valverde,
1998); o desenvolvimento de
um modelo de sistema secundário simplificado: com vários
graus de liberdade, linearelástico,
formado por elementos tubulares, conexões e suportes com
molas (Castañaga,
1998); a introdução do efeito inelástico nos elementos
tubulares e suportes do sistema
secundário simplificado e definição de um fator de
dutilidade global do sistema para
relacionar, qualitativa e quantitativamente, o espectro de
resposta acoplada do sistema
secundário simplificado, sob comportamento elástico e
inelástico (Sampaio, 2003).
Agora, um outro avanço é incorporado, com o presente
estudo, o da influência de
cargas estáticas nos elementos devidas à pressão interna e
variação de temperatura,
nessas relações do espectro de resposta elástica e
inelástica. Também é feita uma
comparação dos espectros de resposta elástica e inelástica
do sistema secundário
acoplado e não acoplado. Espectros médios aproximados para
a resposta inelástica
acoplada do sistema secundário simplificado são também
propostos. / [en] The analysis of secondary structure systems to seismic
loads is a special and open
subject in the design of industrial installations. Two
particular points attract specialist
attention and effort on the way of a more realist,
comprehensive and economical
design: the dynamical properties interaction between the
secondary and principal
systems and the amount of the secondary system ductility
which can or should be
considered in the design. It is very clear at this stage
that the designer decision has to be
well advised because depending on circumstances the final
results may show very
surprising. The context of experiences on this subject, at
PUC-Rio, includes a series of
initiatives. Among them, one may to give special mention
to the following: the study
and proposal of a methodology to develop a coupled floor
response spectrum
(Valverde, 1998); the development of a simplified
secondary system model: multidegree,
linear-elastic, tubular elements and connexions and spring
supports (Castañaga,
1998); the introduction of inelastic action in the tubular
elements and supports of the
simplified secondary system and the definition of a system
overall ductility factor to
relate, qualitative and quantitatively, the simplified
secondary system coupled response
spectrum under elastic and inelastic behavior (Sampaio,
2003). Now, another
advancement is enhanced with this study on the influence
of element static loads due to
internal pressure and temperature variation on these
elastic and inelastic response
spectrum relationships. Comparison also is made into
coupled and uncoupled
secondary system elastic and inelastic response spectra.
Approximated medium
response spectra for the inelastic coupled response of a
simplified secondary system are
also proposed.
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Rehabilitation of Exterior RC Beam-Column Joints using Web-Bonded FRP SheetsMahini, Seyed Saeid Unknown Date (has links)
In a Reinforced Concrete (RC) building subjected to lateral loads such as earthquake and wind pressure, the beam to column joints constitute one of the critical regions, especially the exterior ones, and they must be designed and detailed to dissipate large amounts of energy without a significant loss of, strength, stiffness and ductility. This would be achieved when the beam-column joints are designed in such a way that the plastic hinges form at a distance away from the column face and the joint region remain elastic. In existing frames, an easy and practical way to implement this behaviour following the accepted design philosophy of the strong-column weak-beam concept is the use a Fibre Reinforced Plastic (FRP) retrofitting system. In the case of damaged buildings, this can be achieved through a FRP repairing system. In the experimental part of this study, seven scaled down exterior subassemblies were tested under monotonic or cyclic loads. All specimens were designed following the strong-column weak-beam principal. The three categories selected for this investigation included the FRP-repaired and FRP-retrofitted specimens under monotonic loads and FRP-retrofitted specimen under cyclic loads. All repairing/retrofitting was performed using a new technique called a web-bonded FRP system, which was developed for the first time in the current study. On the basis of test results, it was concluded that the FRP repairing/retrofitting system can restore/upgrade the integrity of the joint, keeping/upgrading its strength, stiffness and ductility, and shifting the plastic hinges from the column face toward the beam in such a way that the joint remains elastic. In the analytical part of this study, a closed-form solution was developed in order to predict the physical behaviour of the repaired/retrofitted specimens. Firstly, an analytical model was developed to calculate the ultimate moment capacity of the web-bonded FRP sections considering two failure modes, FRP rupture and tension failure, followed by an extended formulation for estimating the beam-tip displacement. Based on the analytical model and the extended formulation, failure mechanisms of the test specimens were implemented into a computer program to facilitate the calculations. All seven subassemblies were analysed using this program, and the results were found to be in good agreement with those obtained from experimental study. Design curves were also developed to be used by practicing engineers. In the numerical part of this study, all specimens were analysed by a nonlinear finite element method using ANSYS software. Numerical analysis was performed for three purposes: to calculate the first yield load of the specimens in order to manage the tests; to investigate the ability of the web-bonded FRP system to relocate the plastic hinge from the column face toward the beam; and to calibrate and confirm the results obtained from the experiments. It was concluded that numerical analysis using ANSYS could be considered as a practical tool in the design of the web-bonded FRP beam-column joints.
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Experimental and numerical studies of masonry wall panels and timber frames of low-rise structures under seismic loadings in IndonesiaSusila, Gede Adi January 2014 (has links)
Indonesia is a developing country that suffers from earthquakes and windstorms and where at least 60% of houses are non-engineered structures, built by unskilled workers using masonry and timber. The non-engineered housing units developed in urban region are also vulnerable to seismic hazard due to the use of low quality of material and constructions method. Those structures are not resistant to extreme lateral loads or ground movement and their failure during an earthquake or storm can lead to significant loss of life. This thesis is concerned with the structural performance of Indonesian low-rise buildings made of masonry and timber under lateral seismic load. The research presented includes a survey of forms of building structure and experimental, analytical and numerical work to predict the behaviour of masonry wall and traditional timber frame buildings. Experimental testing of both masonry and timber have been carried out in Indonesia to establish the quality of materials and to provide material properties for numerical simulations. The experimental study found that the strength of Indonesia-Bali clay brick masonry are below the minimum standard required for masonry structures built in seismic regions, being at least 50% lower than the requirement specified in British Standard and Eurocode-6 (BS EN 1996-1-1:2005). In contrast, Indonesian timber materials meet the strength classes specified in British Standard/Eurocode- 5 (BS EN 338:2009) in the range of strength grade D35-40 and C35).Structural tests under monotonic and cyclic loading have been conducted on building components in Indonesia, to determine the load-displacement capacity of local hand-made masonry wall panels and timber frames in order to: (1) evaluate the performance of masonry and timber frame structure, (2) investigate the dynamic behaviour of both structures, (3) observe the effect of in-plane stiffness and ductility level, and (4) examine the anchoring joint at the base of timber frame that resists the overturning moment. From these tests, the structural ductility was found to be less than two which is below the requirement of the relevant guidelines from the Federal Emergency Management Agency, USA (FEMA-306). It was also observed that the lateral stiffness of masonry wall is much higher than the equivalent timber frame of the same height and length. The experimental value of stiffness of the masonry wall panel was found to be one-twelfth of the recommended values given in FEMA-356 and the Canadian Building code. The masonry wall provides relatively low displacement compared to the large displacement of the timber frame at the full capacity level of lateral load, with structural framing members of the latter remaining intact. The weak point of the timber frame is the mechanical joint and the capacity of slip joint governs the lateral load capacity of the whole frame. Detailed numerical models of the experimental specimens were setup in Abaqus using three-dimensional solid elements. Cohesive elements were used to simulate the mortar behaviour, exhibiting cracking and the associated physical separation of the elements. Appropriate contact definitions were used where relevant, especially for the timber frame joints. A range of available material plasticity models were reviewed: Drucker-Prager, Crystalline Plasticity, and Cohesive Damage model. It was found that the combination of Crystalline Plasticity model for the brick unit and timber, and the Cohesive Damage model for the mortar is capable of simulating the experimental load-displacement behaviour fairly accurately. The validated numerical models have been used to (1) predict the lateral load capacity, (2) determine the cracking load and patterns, (3) carry out a detailed parametric study by changing the geometric and material properties different to the experimental specimens. The numerical models were used to assess different strengthening measures such as using bamboo as reinforcement in the masonry walls for a complete single storey, and a two-storey houses including openings for doors and windows. The traditional footing of the timber structures was analysed using Abaqus and was found to be an excellent base isolation system which partly explains the survival of those structures in the past earthquakes. The experimental and numerical results have finally been used to develop a design guideline for new construction as well as recommendations for retrofitting of existing structures for improved performance under seismic lateral load.
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