1,721,251 research outputs found
Special Issue on Structural Failures in Earthquakes
No full textAdam Martínez, JM.; Ingham, J. (2013). Editorial (Structural Failures in Earthquakes). ENGINEERING FAILURE ANALYSIS. 34:536-536. doi:10.1016/j.engfailanal.2013.07.029S5365363
Damping considerations for rocking block dynamics using the discrete element method
Full text linkIt is well established that unreinforced masonry (URM) buildings develop damage-forming collapse mechanisms during high-intensity earthquakes, with these mechanisms exhibiting large rocking displacements before collapsing. The Discrete Element Method (DEM) of analysis can realistically capture phenomena that involve large movements of elements, resulting in the technique being ideal for simulating the collapse of URM building elements. Consequently, extensive research using DEM to analyse the seismic response of URM buildings and building components has recently been published. However, the variety of reported damping approaches that have apparently led to DEM results that successfully replicate physical observations underscores the need for consistent guidance related to the assignment of damping factors. The Rayleigh damping distribution model implemented in the DEM software 3DEC was used to study the differences between mass proportional (MP) and stiffness proportional (SP) damping configurations. After reviewing phenomena that need to be damped and previous works where damping was implemented, the capabilities and drawbacks of the time-efficient MP damping configuration were studied and the results compared to simulations with SP damping. When considering numerical simulations that incorporated MP damping and led to results that were seemingly well-matched to experimental tests, it was found that the apparent robustness of decisions pertaining to the adopted input parameters was deceptive in most cases. Consequently, SP damping was recommended for all DEM rocking simulations, even though MP damping could be used with satisfactory accuracy in certain situations discussed herein. A pragmatic relationship between both damping strategies was proposed
An inventory of unreinforced load-bearing stone masonry buildings in New Zealand
Full text linkAlmost all unreinforced stone masonry (URSM) buildings in New Zealand were constructed between 1860 and 1910, typically in regions where natural stone was sourced from local quarries, fields and rivers. These buildings form an important part of the country’s architectural heritage, but the performance of URSM buildings during earthquake induced shaking can differ widely due to many aspects related to the constituent construction materials and type of masonry wall cross-section morphology. Consequently, as a step towards gaining greater knowledge of the New Zealand URSM building stock and its features, an exercise was undertaken to identify and document the country-wide URSM building inventory. The compiled building inventory database includes: (i) general building information, such as address, building owner/tenant and building use; (ii) architectural configuration, such as approximate floor area, number of storeys, connection with other buildings, plan and elevation regularity; and (iii) masonry type, such as stone and mortar types, wall texture and wall cross-section morphology. From this exercise it is estimated that there is in excess of 668 URSM buildings currently in existence throughout New Zealand. A large number of these vintage URSM buildings require detailed seismic assessment and the implementation of seismic strengthening interventions in order to conserve and enhance this component of New Zealand’s cultural and national identity. The entire stock of identified buildings is reported in the appended annex (688 total), including 20 URSM buildings that were demolished following the Canterbury earthquake sequence
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Performance of unreinforced stone masonry buildings during the 2010/2011 Canterbury earthquake swarm and retrofit technique for their seismic improvement
No full textPresents a post-earthquake assessment and building damage statistics for unreinforced stone masonry buildings in the city to document the performance of the structures. Gives details on typical building characteristics and on failure modes observed. Talks about damage mechanisms in stone masonry buildings and churches and retrofit interventions
Using DEM to Investigate Boundary Conditions for Rocking URM Facades Subjected to Earthquake Motion
Full text linkFaçade overturning is a frequently observed collapse mechanism occurring in unreinforced masonry (URM) buildings during high-intensity, earthquake-induced shaking. Following complete separation from a building, the rocking motion of a URM façade and the associated impact against the return walls are the factors that continue to contribute to the façade out-of-plane capacity. Seismic vulnerability studies of URM façades have historically neglected the interaction between building earthquake response and the rocking response of the façade, whereas in the study reported herein this interaction was analyzed using the discrete element modeling (DEM) approach, resulting in a façade out-of-plane capacity reduction. The increment in the dynamic rocking capacity caused by the frictional connection between the URM façade and the building was also analyzed and is reported
Seismic Structural Assessment of the Christchurch Catholic Basilica, New Zealand
No full textAn evaluation of the seismic performance of the Christchurch Catholic Basilica, New Zealand, also known as the Cathedral of the Blessed Sacrament, is presented. The cultural importance of the Basilica has been recognised, as it is listed as a Category I building on the New Zealand heritage register. Four strong earthquakes that occurred between September 2010 and June 2011 caused progressive damage and local collapse in the Basilica. Numerical analyses were performed to allow a seismic assessment of the Basilica using the Finite Element Method. A macro-modelling approach following homogenization concepts was considered and the seismic behaviour of the structure was evaluated through pushover analysis with the distribution of forces being proportional to the mass. The analyses allowed damage patterns and capacity curves to be determined, and identified the most vulnerable elements, the maximum load capacity, and the expected collapse mechanisms. Furthermore, a comparison between the numerical output and the existing crack patterns was undertaken, and good agreement was obtained. Finally, two strengthening techniques were evaluated with the aim of reducing the seismic vulnerability of the structure by avoiding collapse of the most vulnerable structural elements
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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