Página 1 dos resultados de 542 itens digitais encontrados em 0.010 segundos

Proposal of a test specimen to evaluate the shear strength of vertical interfaces of running bond masonry walls

CAPUZZO NETO, Valentim; CORREA, Marcio R. S.; RARNALHO, Marcio A.
Fonte: NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS Publicador: NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.47%
There is no normalized test to assess the shear strength of vertical interfaces of interconnected masonry walls. The approach used to evaluate this strength is normally indirect and often unreliable. The aim of this study is to propose a new test specimen to eliminate this deficiency. The main features of the proposed specimen are failure caused by shear stress on the vertical interface and a small number of units (blocks). The paper presents a numerical analysis based on the finite element method, with the purpose of showing the theoretical performance of the designed specimen, in terms of its geometry, boundary conditions, and loading scheme, and describes an experimental program using the specimen built with full- and third-scale clay blocks. The main conclusions are that the proposed specimen is easy to build and is appropriate to evaluate the sheaf strength of vertical interfaces of masonry walls.

Parametrical study of masonry walls subjected to in-plane loading through numerical modeling

HAACH, Vladimir G.; VASCONCELOS, Graca; LOURENCO, Paulo B.
Fonte: ELSEVIER SCI LTD Publicador: ELSEVIER SCI LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.59%
This paper deals with the numerical assessment of the influence of parameters such as pre-compression level, aspect ratio, vertical and horizontal reinforcement ratios and boundary conditions on the lateral strength of masonry walls under in-plane loading. The numerical study is performed through the software DIANA (R) based on the Finite Element Method. The validation of the numerical model is carried out from a database of available experimental results on masonry walls tested under cyclic lateral loading. Numerical results revealed that boundary conditions play a central role on the lateral behavior of masonry walls under in-plane loading and determine the influence of level of pre-compression as well as the reinforcement ratio on the wall strength. The lateral capacity of walls decreases with the increase of aspect ratio and with the decrease of pre-compression. Vertical steel bars appear to have almost no influence in the shear strength of masonry walls and horizontal reinforcement only increases the lateral strength of masonry walls if the shear response of the walls is determinant for failure, which is directly related to the boundary conditions. (C) 2011 Elsevier Ltd. All rights reserved.; European Commission[COOP-CT-2005-018120]; Programme Alssan...

Cisalhamento nas interfaces verticais de paredes de edifícios de alvenaria estrutural; Shear stress on vertical interfaces of structural masonry walls

Oliveira, Luciane Marcela Filizola de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 19/05/2009 PT
Relevância na Pesquisa
46.55%
Este trabalho apresenta a avaliação das tensões de cisalhamento nas interfaces verticais de paredes de alvenaria interconectadas em casos onde atuam simultaneamente carregamentos verticais e ações horizontais. Os valores obtidos para as máximas tensões de cisalhamento são comparados com as resistências estabelecidas na norma brasileira em vigor, NBR 10837 (ABNT, 1989), e no texto base para sua revisão. Os valores das referidas normas também são confrontados com valores experimentais, avaliando-se criticamente a aplicação dos limites normativos na prática de projetos de edifícios existentes. Adicionalmente, são avaliadas duas formas distintas de modelagem de edifícios de alvenaria estrutural, quando submetidos às ações horizontais. A primeira consiste em uma abordagem simplificada e bastante usual entre projetistas, a associação plana de paredes isoladas. Sua aferição é importante para fornecer ao projetista uma ferramenta que lhe permita obter resultados de maneira rápida e confiável. A segunda forma de modelagem é uma análise de pórtico tridimensional que permite uma análise mais completa das paredes de contraventamento, incluindo os efeitos das deformações por cisalhamento. Com o intuito de avaliar as diferenças observadas entre os dois modelos...

Análise experimental e numérica do comportamento de junta em painéis de contraventamento de alvenaria estrutural; Experimental and numerical analysis of the joint behavior of masonry shear wall

Mata, Rodrigo Carvalho da
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/06/2011 PT
Relevância na Pesquisa
46.36%
A avaliação da capacidade de carga das estruturas de alvenaria submetidas a ações horizontais depende da confiabilidade dos modelos de dimensionamento utilizados. De fato, a alvenaria é um material heterogêneo com característica ortotrópicas. Além disso, por possuir juntas de argamassa que acarretam planos de fraqueza, geralmente a modelagem computacional desse tipo de estrutura apresenta grandes dificuldades. Um modelo robusto para alvenaria só pode ser desenvolvido por meio de uma descrição suficientemente precisa do comportamento mecânico individual de cada um dos seus componentes (unidades de alvenaria e a argamassa) e sobretudo nas juntas de argamassa, as quais são responsáveis pela maior parte dos fenômenos não-lineares que ocorrem na estrutura. Entretanto, diante da escassez de resultados experimentais, descrever esses comportamentos com a precisão e o rigor necessários é uma tarefa bastante difícil. Diante desta motivação, este trabalho se propôs a identificar e quantificar a influência da ligação unidade-argamassa, denominada junta, no comportamento estrutural de painéis de contraventamento de alvenaria estrutural executados com blocos de concreto. Assim, foram obtidos dados experimentais do comportamento da ligação unidade-argamassa e das partes componentes que posteriormente foram utilizados em modelagens computacionais realizadas para prever o comportamento estrutural de painéis de contraventamento submetidos a esforços horizontais no plano. Posteriormente...

Estudo teórico e experimental do comportamento das interfaces verticais de paredes interconectadas de alvenaria estrutural; Numerical and experimental study of the behaviour of vertical interfaces of interconnected structural masonry walls

Oliveira, Luciane Marcela Filizola de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/06/2014 PT
Relevância na Pesquisa
36.56%
A ação estrutural monolítica de paredes interconectadas é dependente da resistência ao cisalhamento da interface, que por sua vez, depende do tipo de ligação entre elas. Neste contexto, o presente trabalho tem por objetivo avaliar o comportamento mecânico das interfaces verticais entre paredes de alvenaria conectadas por amarração direta e por amarração indireta com grampos de barras de aço CA-50 com 10 mm de diâmetro. Para compreensão do mecanismo de funcionamento das ligações foram realizados ensaios de caracterização dos materiais, dos componentes e da alvenaria, além de ensaios de cisalhamento direto em quatro séries de seis corpos de prova de cinco fiadas, em formato H e em escala natural. Nas séries ensaiadas foi variado o tipo de ligação e o material do bloco, sendo a primeira produzida com blocos de concreto e amarração direta, a segunda com blocos cerâmicos com amarração direta, a terceira com blocos de concreto e amarração indireta e a quarta com blocos cerâmicos e amarração indireta. Todos os corpos de prova foram assentados com argamassamento lateral e argamassa de traço 1:1:6 em volume. Na análise experimental foi investigada a força de ruptura, a relação tensão-deformação específica...

Um modelo computacional para a análise global tridimensional da estrutura de edifícios altos de concreto armado com a presença de paredes estruturais; A computational model for 3D global structure analyses of high-rise reinforced concrete buildings with the consideration of shear walls

Bernardi, Douglas Francescatto
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
66.59%
A crescente valorização das áreas disponíveis para a construção de edifícios nas grandes cidades tem constantemente elevado a altura das edificações. Nos edifícios altos, a consideração das ações horizontais na verificação da estabilidade da construção passa a ter um caráter essencial. As ações horizontais podem ser absorvidas, basicamente, por dois sistemas estruturais: por uma estrutura composta por pórticos de grande rigidez ou pela combinação de pórticos e paredes estruturais. Dentro deste contexto, esta dissertação trata da análise tridimensional de estruturas de edifícios altos de concreto armado, considerando a presença de paredes estruturais. Ao longo do trabalho é desenvolvido um modelo computacional em linguagem FORTRAN 90, baseado no Método dos Elementos Finitos, para realizar este tipo de análise. O modelo segue as recomendações da NBR6118 (ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS, 2007). Conforme esta norma, a não linearidade física é considerada de forma simplificada pela redução da rigidez dos elementos através de um fator fixo, função do nível de fissuração esperado A não linearidade geométrica, por outro lado, pode ser considerada de maneira simplificada ou de forma exata a partir de uma formulação desenvolvida por Argyris et al. (1979). No modelo analisado...

Dry joint stone masonry walls subjected to in-plane combined loading

Lourenço, Paulo B.; Oliveira, Daniel V.; Roca, Pere; Orduña Bustamante, A.
Fonte: ASCE Publicador: ASCE
Tipo: Artigo de Revista Científica
Publicado em //2005 ENG
Relevância na Pesquisa
46.33%
The paper presents the results of experimental research on the structural behavior of dry joint masonry. The most relevant experimental results concern the strength response of stone dry joint masonry walls subjected to in-plane combined compressive and shear loading. Significant features of the structural behavior shown by the walls are discussed and conclusions on their ultimate capacity and observed failure mechanisms are addressed. Complementarily, the application of an existing numerical model, stemming from plasticity and based on a micromodeling strategy, is also presented and discussed with regard to its capacity to simulate the obtained experimental results. The model was calibrated with data collected from complementary tests carried out on specimens and prisms made of the same type of stone. Finally, the usage of a simplified method of analysis based on a continuum of diagonal struts is also addressed.

Homogenised limit analysis of masonry walls : part II : structural examples

Milani, G.; Lourenço, Paulo B.; Tralli, A.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2006 ENG
Relevância na Pesquisa
56.33%
The homogenised failure surfaces obtained through the simple micro-mechanical model developed in the first part of the paper are here used for the analysis of in-plane loaded masonry walls. Both upper and lower bound homogenised limit analyses are employed for treating meaningful structural cases, namely a deep beam and a set of shear walls. Detailed comparisons between the experimental data and numerical results obtained using both a heterogeneous and a homogenised approach are also presented. The examples show the efficiency of the homogenised technique with respect to: 1) accuracy of the results; 2) reduced number of finite elements required; 3) independence of the mesh, at a structural level, from the actual texture of masonry. A final example on a large scale wall is presented with the aim to show an engineering application of the proposed approach.; Project MIUR COFIN 2003 – "Interfacial damage failure in structural systems".

Masonry shear walls subjected to cyclic loading : influence of confinement and horizontal reinforcement

Gouveia, João P.; Lourenço, Paulo B.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2007 ENG
Relevância na Pesquisa
46.36%
The behavior of masonry shear walls is fundamental in the design of masonry buildings subjected to different actions, namely of seismic nature. The usage of unreinforced, confined or reinforced masonry is currently subjected to a strong debate in Europe due to the new codes. In particular, the part of Eurocode 8 (Design of structures for earthquake resistance) related to masonry structures is only a limited compromise for the different countries. A large testing program was started at University of Minho in order to clarify issues regarding confined masonry and unfilled vertical joints. Confined masonry is assumed as a hybrid material joining masonry with small section horizontal and vertical lightly reinforced concrete elements. This project, partly sponsored by the light-weight concrete block industry, aims at defining adequate structural solutions for regions of low to high seismicity in Portugal. This paper discusses the results of the experimental program, consisting mainly of masonry walls subjected to cyclic actions and constant pre-compression. Sixteen specimens are considered, being the shear strength, ductility, energy dissipation and stiffness discussed. The key aspects under discussion are: (a) the possibility of replacing the filling of the vertical joints by interlocking and horizontal bed joint reinforcement...

Experimental investigations on the mechanics of stone masonry : characterization of granites and behavior of ancient masonry shear walls; Investigação experimental na mecânica da alvenaria de pedra : caracterização de granitos e comportamento de paredes antigas de alvenaria de pedra

Vasconcelos, Graça
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Tese de Doutorado
Publicado em //2005 ENG
Relevância na Pesquisa
36.59%
Tese de doutoramento em Engenharia Civil; The work presented in this thesis was developed at the Department of Civil Engineering of University of Minho. This work is eminently experimental and intends to be a valuable contribution to a better insight on the mechanics of stone masonry. In order to improve the knowledge on the mechanical properties of granite, the constitutive behavior of distinct granite types under tensile and compressive loading was successfully obtained through a set of experimental tests associated to suitable displacement control. Afterwards, elastic and fracture properties were derived and statistical correlations among these parameters were obtained. The selection of different types of granitic rocks made possible the analysis of the influence of some microstructural aspects, such as grain size and internal texture on the large range of elastic and fracture properties. Other aspects that can explain the variation of the tensile and compressive engineering properties, like weathering state, moisture content and physical properties were also investigated. The possibility of predicting the mechanical and physical properties of the granites by simple and economical nondestructive techniques, such as the ultrasonic pulse velocity (UPV) and the Schmidt hammer rebound number (N) was studied. A set of statistical correlations between the elastic and strength properties and the experimental data obtained through nondestructive techniques were defined. Moreover...

Finite element modelling of deformation characteristics of historical stone masonry shear walls

Senthivel, Ramakrishnan; Lourenço, Paulo B.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Artigo de Revista Científica
Publicado em //2009 ENG
Relevância na Pesquisa
56.45%
Two dimensional nonlinear finite element analysis based on experimental test data has been carried out to model deformation characteristics, such as load-displacement envelope diagrams and failure modes of historical stone masonry shear walls subjected to combined axial compression and lateral shear loading. An experimental research work was carried out on three different types of historical stone masonry shear walls that can be considered representative of ancient stone masonry constructions. Those three types of masonry are: i) sawn dry-stack or dry-stone masonry without bonding mortar, ii) irregular stone masonry with bonding mortar, and iii) rubble masonry with irregular bonding mortar thickness. Plasticity theory based micro modelling techniques has been used to carry out the analysis. The stone units were modelled using an eight node continuum plane stress elements with full Gauss integration. The joints and unit-joint interfaces were modelled using a six node zero thickness line interface elements with Lobatto integration. This paper outlines the experimental research work, details of numerical modelling carried out and report the numerical lateral load-displacement diagrams and failure modes. The numerical analysis results were compared with the experimental test results and good agreement was found.

Parametrical study of masonry walls subjected to in-plane loading through numerical modeling

Haach, V.; Vasconcelos, Graça; Lourenço, Paulo B.
Fonte: Elsevier, Ltd Publicador: Elsevier, Ltd
Tipo: Artigo de Revista Científica
Publicado em /04/2011 ENG
Relevância na Pesquisa
36.53%
This paper deals with the numerical assessment of the influence of parameters such as pre-compression level, aspect ratio, vertical and horizontal reinforcement ratios and boundary conditions on the lateral strength of masonry walls under in-plane loading. The numerical study is performed through the software DIANA® based on the Finite Element Method. The validation of the numerical model is carried out from a database of available experimental results on masonry walls tested under cyclic lateral loading. Numerical results revealed that boundary conditions play a central role on the lateral behavior of masonry walls under in-plane loading and determine the influence of level of pre-compression as well as the reinforcement ratio on the wall strength. The lateral capacity of walls decreases with the increase of aspect ratio and with the decrease of pre-compression. Vertical steel bars appear to have almost no influence in the shear strength of masonry walls and horizontal reinforcement only increases the lateral strength of masonry walls if the shear response of the walls is determinant for failure, which is directly related to the boundary conditions.

Study of the behaviour of reinforced masonry wallets subjected to diagonal compression through numerical modelling

Haach, V. G.; Vasconcelos, Graça; Lourenço, Paulo B.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em /07/2014 ENG
Relevância na Pesquisa
36.47%
Shear walls are subjected to flexure and shear efforts in conjunction with compressive stresses associated to the gravity loads. In shear mode, diagonal cracks develop at the unit-mortar interface or both at the unit-mortar interface and through units as result of a biaxial tension-compression stress state, which in unreinforced masonry generally mean the collapse. The brittle failures of unreinforced masonry shear walls, which are more remarkable with high axial loads, may be prevented by the use of steel reinforcement. Diagonal compression tests allow obtaining a good prediction of the tensile strength of masonry walls in this biaxial tension-compression stress state. This paper aims to study the behaviour of reinforced masonry in diagonal compression tests through numerical modelling. A series of diagonal compression tests carried out on concrete block masonry with distinct types of reinforcement’s arrangements are modelled using the software DIANA®. Results indicate that horizontal and vertical reinforcements applied in conjunct provide an increase on the shear strength and ductility. On the other hand, the application of horizontal reinforcements alone leads only to an increase of ductility.

Effect of relative humidity on creep-shrinkage behaviour of composite tall buildings

Chowdhary,Peeyush; Sharma,Ravi K.
Fonte: Associação Brasileira de Ciências Mecânicas Publicador: Associação Brasileira de Ciências Mecânicas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2013 EN
Relevância na Pesquisa
46.27%
Relative humidity of environment affects creep and shrinkage behaviour of a concrete member of composite tall buildings. These buildings are more prone to redistribution of forces as adjacent steel columns and RCC shear walls have quite different characteristics. In this paper, study is carried out to evaluate the effect of relative humidity of environment for a composite building using analytical prediction model, CEB-FIP updated 1999 as the facility of short term testing may not be always available and thus, prediction of creep and shrinkage of concrete at any time by extrapolation is not possible. An accurate procedure, Consistent Procedure, CP available in literature is modified by incorporating analytical prediction model CEB-FIP updated 1999. It has been shown that differential deflections in a composite frame shear wall system are significantly affected by relative humidity. It has been further reported that although, the steel columns have only elastic deformation for the chosen composite frame systems, there is significant increase in design forces when relative humidity decreases.

Effect of lightweight and low-strength concrete on seismic performance of thin lightly-reinforced shear walls

Carrillo J.; Lizarazo J.M.; Bonett R.
Fonte: Elsevier Ltd Publicador: Elsevier Ltd
Tipo: Article; info:eu-repo/semantics/article
ENG
Relevância na Pesquisa
66.71%
Although several research programs have investigated the performance of structural elements made of lightweight concrete, there is a limited understanding of the behavior of lightweight shear walls under seismic conditions. In this paper is summarized an experimental study that comprised quasi-static cyclic tests and shake table tests of twenty walls, conducted to provide information on the effect of lightweight and low-strength concrete on seismic performance of thin lightly-reinforced shear walls. Test results indicate that shear strength, drift ratios and energy dissipated at different limit states of lightweight concrete walls were larger in comparison to walls made of normalweight concrete. Measured performance also indicate that the reduction factor proposed by ACI 318-11 and NTC-C does not capture adequately the influence of lightweight and low-strength concrete. Thus, shear strength of thin lightly-reinforced, lightweight concrete shear walls can be calculated without any modification factor. © 2015 Elsevier Ltd.

RC Shear Walls: Full-Scale Cyclic Test, Insights and Derived Analytical Model

BEKO Adrian; ROSKO Peter; WENZEL Helmut; PEGON Pierre; MARKOCIC Damijan; MOLINA RUIZ Francisco Javier
Fonte: ELSEVIER SCI LTD Publicador: ELSEVIER SCI LTD
Tipo: Articles in periodicals and books Formato: Printed
ENG
Relevância na Pesquisa
46.53%
The unpredictable consequences of earthquakes have proven the necessity to study the shear mechanism of low-rise reinforced concrete walls further. Experimental testing remains the preferred approach to gather insight into the workings of the material and structural elements as the complex behavior of reinforced concrete does not lend itself to widely applicable generalized solutions. The contribution deals with cyclic testing of full-scale low aspect ratio reinforced concrete walls in a principally uniform shear state. An approach with various novel aspects in testing massive specimens is introduced. The obtained data was analyzed resulting in well-defined hysteresis curves. Characteristics of ultimate shear capacity, energy dissipation, damping and nonlinear effects are discussed. It was found that the sequence of load cycle amplitudes at the quasi-static rate does not significantly influence ultimate strength or overall behavior of the wall. Yet, hysteretic damping ratios depend on loading history and range from values considerably higher than commonly assumed in design to values that are lower. An advanced shear strength calculation is presented to relate the findings to previous research. A nonlinear mathematical model is described which is capable of simulating the hysteresis of the tested shear walls. The reported developments are applicable in design of structures.; JRC.G.4-European laboratory for structural assessment

RC Shear Walls: Full-Scale Cyclic Test, Insights and Derived Analytical Model

BEKO Adrian; ROSKO Peter; WENZEL Helmut; PEGON Pierre; MARKOVIC Damijan; MOLINA RUIZ Francisco Javier
Fonte: ELSEVIER SCI LTD Publicador: ELSEVIER SCI LTD
Tipo: Articles in periodicals and books Formato: Printed
ENG
Relevância na Pesquisa
46.53%
The unpredictable consequences of earthquakes have proven the necessity to study the shear mechanism of low-rise reinforced concrete walls further. Experimental testing remains the preferred approach to gather insight into the workings of the material and structural elements as the complex behavior of reinforced concrete does not lend itself to widely applicable generalized solutions. The contribution deals with cyclic testing of full-scale low aspect ratio reinforced concrete walls in a principally uniform shear state. An approach with various novel aspects in testing massive specimens is introduced. The obtained data was analyzed resulting in well-defined hysteresis curves. Characteristics of ultimate shear capacity, energy dissipation, damping and nonlinear effects are discussed. It was found that the sequence of load cycle amplitudes at the quasi-static rate does not significantly influence ultimate strength or overall behavior of the wall. Yet, hysteretic damping ratios depend on loading history and range from values considerably higher than commonly assumed in design to values that are lower. An advanced shear strength calculation is presented to relate the findings to previous research. A nonlinear mathematical model is described which is capable of simulating the hysteresis of the tested shear walls. The reported developments are applicable in design of structures.; JRC.G.4-European laboratory for structural assessment

Simulation of reinforced concrete short shear wall subjected tocyclic loading

PARULEKAR Yogita; REDDY G. R.; VAZE K.k.; PEGON Pierre; WENZEL Helmut
Fonte: ELSEVIER SCIENCE SA Publicador: ELSEVIER SCIENCE SA
Tipo: Articles in periodicals and books Formato: Printed
ENG
Relevância na Pesquisa
36.51%
This paper addresses the strength and deformation capacity of stiff squat shear wall subjected to monotonic and pseudo-static cyclic loading using experiments and analysis. Reinforced concrete squat shear walls offer great potential for lateral load resistance and the failure mode of these shear walls is brittle shear mode. Shear strength of these shear walls depend strongly on softening of concrete struts in principal compression direction due to principal tension in other direction. In this work simulation of the behavior of a squat shear wall is accurately predicted by finite element modeling by incorporating the appropriate softening model in the program. Modification of model of concrete in the softening part is suggested and reduction factor given by Vecchio et al. (1994) is used in the model. The accuracy of modeling is confirmed by comparing the simulated response with experimental one. The crack pattern generated from the 3D model is compared with that obtained from experiments. The load deflection for monotonic loads is also obtained using softened truss theory and compared with experimental one.; JRC.G.4-European laboratory for structural assessment

Seismic strengthening of RC frames with shear walls

TSIONIS Georgios; TAUCER Fabio; PINTO VIEIRA Artur
Fonte: University of Porto Publicador: University of Porto
Tipo: Articles in periodicals and books Formato: CD-ROM
ENG
Relevância na Pesquisa
46.42%
Experimental testing and numerical analyses of elements and structures have demonstrated the feasibility and effectiveness of shear walls for the seismic retrofit of existing reinforced concrete frame buildings. The paper presents a literature review and discusses the effect of the most important parameters. It is shown that shear walls improve the global response of existing buildings in terms of stiffness, strength and displacement demand and that their effectiveness is increased for walls with larger dimensions. The design and detailing of the dowels and anchorage bars used for the connection between new and existing elements is a critical issue. The results available in literature, complemented by parametric numerical analyses, may provide the basis for the development of design guidelines with emphasis on strength and stiffness characteristics and on detailing of the connections.; JRC.G.4-European laboratory for structural assessment

Dynamic analysis of coupled shear walls and sandwich beams

Skattum, Knut Sverre
Fonte: California Institute of Technology Publicador: California Institute of Technology
Tipo: Report or Paper; PeerReviewed Formato: application/pdf
Publicado em 01/01/1971
Relevância na Pesquisa
46.47%
A study is made of the free vibration of planar coupled shear walls, a common lateral load-resisting configuration in building construction where two walls are coupled together by a system of discrete spandrel beams. The differential equations and boundary conditions are obtained by the variational method, and by assuming that the spandrels can be replaced by a continuous system of laminae, or small beams. Natural frequencies and mode shapes are determined, and the results are presented in a number of figures from which the natural frequencies of any coupled shear wall can be extracted. The importance of including vertical displacement in the analysis is discussed, and a study of the effect of neglecting the vertical inertia term is given. These cases are illustrated with graphs and with one specific example. Investigations are also made of the asymptotic behavior of the system as the spandrels become weak, as they become stiff, and as the frequencies become large. Finally, the theory of sandwich beams is presented and compared to that for coupled shear walls. It is observed that for most cases of constant properties, the differential equations (and boundary conditions) reduce to the same mathematical form for both theories.