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Author: Hossein Derakhshan
Publisher:
ISBN:
Category : Buildings
Languages : en
Pages : 341
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Book Description
This thesis investigates the behaviour of URM walls subjected to out-of-plane seismic forces, and the study is focused primarily on single-storey and two-storey one-way spanning walls connected to flexible diaphragms. Expressions that describe the intermediate-height cracking of out-of-plane loaded one-way spanning URM walls were formulated, and wall force-displacement behaviour and the sensitivity to various parameters were studied. Crack height was identified to be particularly sensitive to low values of masonry bond strength and/or to low values of applied overburden. Crack height was found to have significant effects on both wall instability displacement and lateral resistance. A comprehensive quasi-static testing programme was developed by subjecting full-scale two-leaf and three-leaf URM walls to out-of-plane uniform forces. The objective of the tests was to develop an idealised predictive model for the out-of-plane behaviour of URM walls, by accounting the effects of different mortar mixes, multi-leaf construction and overburden loads. An in-field out-of-plane pushover testing programme was next completed, and some of the key questions about actual wall performance were answered. Wall support types and characteristics and their effect on wall behaviour were investigated by testing multiple walls having different support configurations, which included timber diaphragms, concrete ring beam, and grouted steel anchorage bars. The effect of plaster and wall finishings was investigated, and the conditions upon which the previously developed idealised predictive model had acceptable results were determined. A simplified reduced-degree-of-freedom numerical model was developed to study the dynamic behaviour of URM walls, with critical requirements of the model being an ability to account for the effects of flexible supports and an ability to predict the behaviour of two-storey walls. An existing assessment procedure for seismic assessment of out-of-plane loaded URM walls was reviewed in detail, an alternative methodology for wall assessment was introduced, and seismic assessment charts were presented for single-storey and two-storey walls.
Author: Hossein Derakhshan
Publisher:
ISBN:
Category : Buildings
Languages : en
Pages : 341
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Book Description
This thesis investigates the behaviour of URM walls subjected to out-of-plane seismic forces, and the study is focused primarily on single-storey and two-storey one-way spanning walls connected to flexible diaphragms. Expressions that describe the intermediate-height cracking of out-of-plane loaded one-way spanning URM walls were formulated, and wall force-displacement behaviour and the sensitivity to various parameters were studied. Crack height was identified to be particularly sensitive to low values of masonry bond strength and/or to low values of applied overburden. Crack height was found to have significant effects on both wall instability displacement and lateral resistance. A comprehensive quasi-static testing programme was developed by subjecting full-scale two-leaf and three-leaf URM walls to out-of-plane uniform forces. The objective of the tests was to develop an idealised predictive model for the out-of-plane behaviour of URM walls, by accounting the effects of different mortar mixes, multi-leaf construction and overburden loads. An in-field out-of-plane pushover testing programme was next completed, and some of the key questions about actual wall performance were answered. Wall support types and characteristics and their effect on wall behaviour were investigated by testing multiple walls having different support configurations, which included timber diaphragms, concrete ring beam, and grouted steel anchorage bars. The effect of plaster and wall finishings was investigated, and the conditions upon which the previously developed idealised predictive model had acceptable results were determined. A simplified reduced-degree-of-freedom numerical model was developed to study the dynamic behaviour of URM walls, with critical requirements of the model being an ability to account for the effects of flexible supports and an ability to predict the behaviour of two-storey walls. An existing assessment procedure for seismic assessment of out-of-plane loaded URM walls was reviewed in detail, an alternative methodology for wall assessment was introduced, and seismic assessment charts were presented for single-storey and two-storey walls.
Author: Charlotte Louise Knox
Publisher:
ISBN:
Category : Buildings
Languages : en
Pages : 289
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Book Description
The research presented in this thesis describes the seismic assessment of perforated unreinforced masonry (URM) walls subjected to in-plane loading through accurate analysis of the wall lateral capacity and seismic demand. Current assessment methods for determining the capacity of perforated URM walls loaded in-plane, as outlined in the New Zealand guideline document (NZSEE 2006), are based on the assumption of infinitely rigid spandrel elements. From observations of damage after the 2010/2011 Canterbury earthquake sequence, this assumption has been proven to be invalid for certain perforated wall geometries. The research reported in this thesis was conducted with the primary aim of developing a practitioner focused assessment tool that accurately captured the global and local response of a perforated URM wall, with an emphasis placed on defining the influence of the spandrel geometry on the system level response of perforated URM walls responding in-plane. Pseudo-static cyclic testing of six full-scale pier-spandrel substructures and a two storey half-scale isolated perforated URM wall was conducted to investigate the variables which control spandrel failure mode and the influence of spandrel failure on the lateral capacity of multi-storey URM walls. Testing showed that the behaviour of the spandrel has a significant effect on the failure mode of the piers and hence the strength, stiffness and energy dissipation capacity of the system. A non-linear Equivalent Frame modelling method for perforated URM walls using the structural analysis software SAP2000 was appropriately validated using modelling results and experimental data. Spandrel behaviour was included within the modelling through the use of a moment-axial failure domain and a shear-axial relationship. Finally, a modified linear elastic procedure for assessing the demand on the in_ plane loaded walls of URM buildings with flexible diaphragms was developed and validated through the use of non-linear time history modelling.
Author: Miha Tomazevic
Publisher: World Scientific
ISBN: 1783262524
Category : Technology & Engineering
Languages : en
Pages : 281
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Book Description
In the last few decades, a considerable amount of experimental and analytical research on the seismic behaviour of masonry walls and buildings has been carried out. The investigations resulted in the development of methods for seismic analysis and design, as well as new technologies and construction systems. After many centuries of traditional use and decades of allowable stress design, clear concepts for limit state verification of masonry buildings under earthquake loading have recently been introduced in codes of practice.Although this book is not a review of the state-of-the-art of masonry structures in earthquake zones, an attempt has been made to balance the discussion on recent code requirements, state-of-the-art methods of earthquake-resistant design and the author's research work, in order to render the book useful for a broader application in design practice. An attempt has also been made to present, in a condensed but easy to understand way, all the information needed for earthquake-resistant design of masonry buildings constructed using traditional systems. The basic concepts of limit state verification are presented and equations for seismic resistance verification of masonry walls of all types of construction, (unreinforced, confined and reinforced) as well as masonry-infilled reinforced concrete frames, are addressed. A method for seismic resistance verification, compatible with recent code requirements, is also discussed. In all cases, experimental results are used to explain the proposed methods and equations.An important part of this book is dedicated to the discussion of the problems of repair, retrofit and rehabilitation of existing masonry buildings, including historical structures in urban centres. Methods of strengthening masonry walls as well as improving the structural integrity of existing buildings are described in detail. Wherever possible, experimental evidence regarding the effectiveness of the proposed strengthening methods is given.
Author: Alistair Peter Russell
Publisher:
ISBN:
Category : Brick walls
Languages : en
Pages : 316
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Book Description
Author: Aníbal Costa
Publisher: Springer Science & Business Media
ISBN: 3642396860
Category : Technology & Engineering
Languages : en
Pages : 350
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Book Description
This present book describes the different construction systems and structural materials and elements within the main buildings typologies, and it analyses the particularities of each of them, including, at the end, general aspects concerning laboratory and in-situ testing, numerical modeling, vulnerability assessment and construction maintenance.
Author: Juan Aleman Hernandez
Publisher:
ISBN:
Category :
Languages : en
Pages : 374
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Book Description
Studies regarding the regional seismicity of New York City (NYC) indicate that earthquakes of magnitude greater than or equal to 5 have a 20-40% probability of occurring in a 50 year period. Considering that more than 50% of the large population of the region (19.1 million) is living in an area where 80% of the buildings are of old Unreinforced Masonry (URM) construction, it is likely that even a moderate earthquake could have critical consequences on public safety and the economy of this area. The main goal of this study was to develop simulation capabilities supported by experimental testing to evaluate the seismic performance of typical unreinforced masonry buildings with flexible diaphragms located in NYC. Simplified nonlinear macro-models of wood diaphragms, masonry walls and floor-to-wall connections were developed and validated individually using data from past experiments. The models are implemented in both commercial and research software to demonstrate their practical use. In particular, a new approach for modeling flexible diaphragms is proposed that is shown to provide similar accuracy to detailed finite element models at a fraction of the computation cost. The models developed were also validated as at the system level, through shake table testing of two full-scale specimens conducted as part of this study. The specimens were designed and constructed to represent the expected loading conditions of a central portion of a one-story URM building and constructed of materials representative of older masonry construction. The tests provide a unique data set that captures the interaction between flexible floors, out-of-plane walls and their connections at, full scale.The validated macro-models can be used for performance-based seismic assessment of unreinforced masonry building in NYC and elsewhere. To demonstrate their use, preliminary studies were conducted to develop out-of-plane URM fragility curves, a building-specific collapse fragility function, and estimate the seismic response of the building when subjected to a ground shaking intensity similar to the 2011 Virginia Earthquake. The probabilistic framework and new performance definitions provided by the FEMA P58 project were used to conduct a performance-based seismic assessment for an archetype unreinforced masonry building in New York City with an emphasis on out-of-plane behavior. This preliminary study served to demonstrate the applicability of the proposed models for applications in performance-based design.
Author: Laura Sendra González
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Out-of-plane stability of unreinforced masonry walls is an important aspect to be taken into account in edification. This construction technique is widely used and it is one of the most vulnerable to seismic loading. It has been observed that damage produced by out-of-plane loadings is one of the most commonly produced failure mechanisms in seismic hazards. Despite of that, research into the out-of-plane stability of masonry walls is not yet enough developed. The aim of this research is to create a three-dimensional finite element model in order to study the latter problem. A parametrical study is performed on two numerical models under monotonic and cyclic out-of-plane loads. The influence of various geometrical and boundary conditions are studied in two different models of a single wall: a homogenized and a distinct model. A damage plasticity formulation, appropriate for brittle materials, is implemented for modeling the behavior of the wall. In the distinct model, frictional and cohesive interaction models are used for modeling the joints, which are constituted by mortar. Firstly a monotonic homogeneous distributed out-of-plane pressure is applied, in order to determine both, the resistance of the wall in terms of its force-displacement curve, and the failure mechanism. Next, the same model is submitted to cyclic out-of-plane uniform pressure and energy dissipation, as well as stiffness degradation is analyzed. Finally, some qualitative recommendations for the unreinforced masonry walls are derived from the results, with the purpose of maximizing the resistance in front of out-of-plane loading.
Author: E. L. Blaikie
Publisher:
ISBN:
Category : Buildings
Languages : en
Pages : 164
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Book Description
Author: Jacques Heyman
Publisher: Cambridge University Press
ISBN: 9780521629638
Category : Architecture
Languages : en
Pages : 176
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Book Description
Cambridge's Jacques Heyman provides a thorough and intuitive understanding of masonry structures, such as arch bridges, Greek temples, and Gothic cathedrals. Although his approach is firmly scientific, Heyman does not use complex mathematics. Instead, he introduces the basis of masonry analysis, then considers individual structures, through lucid and informative text. 5 photos. 100 line diagrams. 3 tables.
Author: Building Seismic Safety Council (U.S.)
Publisher: DIANE Publishing
ISBN: 9781568069913
Category : Science
Languages : en
Pages : 268
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Book Description
Provides engineers involved with the seismic evaluation of existing buildings with guidance concerning the potential earthquake related risk to human life posed by a building or building component.
