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Aspetti strutturali e criticità nelle soluzioni ad esoscheletro per il recupero integrato degli edifici esistenti
No full textEffects of the In-Plane Flexural Behavior Modeling Choices for Hollow Clay Masonry Brickwork with Horizontal Holes
Full text linkBuildings with load-bearing structures made of hollow clay blocks with horizontal holes and ce-ment-based mortar are quite common in Italy, yet the current design standards do not consider specific modeling issues to be addressed by practicing engineers. In the absence of peculiar specifi-cations, the prescriptions given for ordinary masonry walls are thus commonly adopted. However, experimental tests proved that walls built with hollow brick masonry performed quite differently from ordinary masonry walls. Considering the in-plane flexural behavior under horizontal loads, unlike ordinary masonry walls that exhibit some ductility, this construction typology performs quite poorly, showing very little deformation capacity and ductility. In recent experimental campaigns, a brittle collapse mechanism was observed due to the toe crush, which entailed the inability of the wall to further withstand the vertical loads. In this paper, the effects of incorrect modeling choices on the characterization of the in-plane behavior of this construction typology and the consequences related to overestimating ductility are discussed; the effects of the reduced ductility on the reliability of the assessment of an existing building as well as on the conceptual design of possible structural retrofit measures are investigated. From the critical discussion, the need emerged to accurately model the in-plane flexural behavior and to update the code provisions to explicitly consider masonry walls with hollow clay bricks with horizontal holes
Preliminary results of energy-based intensity measures for rocking wall panels subjected to single pulses
No full textThe studies on the dynamic response of free-standing rigid rocking blocks under earthquakes excitations are typically focused on the prevention of collapse, related to their overturning. In recent years many authors focused their interest on the effect of recent severe earthquake, frequently near-fault, leading to the definition of useful stability-diagrams that find their main application for the assessment of the vulnerability of ancient buildings and monuments manifesting the rocking behaviour. Although much research has been focused on the relationship between seismic intensity measures and overturning or potential damage, not many of the analysed quantitative indexes are defined according to an energy-based approach. Considering rigid rocking wall panels of different slenderness, this research attempts to evaluate the correlation between ground-motion parameters, seismic integral parameters (defined according to the energy-based approach) and potential damage in structural engineering application, under the assumption of small rotational angles. The preliminary results of the research show the high dependency between the induced maximum rotation, the input energy, and the maximum rotational energy of the blocks subjected to single pulses
Experimental test to evaluate the in-plane flexural behavior of hollow brick masonry walls with horizontal holes
No full textThe increased awareness of the poor seismic performance of masonry buildings made of clay hollow bricks with horizontal holes and cement-based mortar, has drawn attention to this masonry typology, which was common practice in the early 1960. In this paper, the in-plane rocking behavior of slender masonry walls is experimentally investigated. The test results confirm that this construction typology performs quite poorly under horizontal loads; a brittle collapse was observed due to the brittle crushing of the pier toe subject to compressive stresses concentration. The brittle collapse mechanism also highlighted the inability of the wall to carry even only the vertical loads once the ultimate in-plane flexural capacity has been reached
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
Riqualificazione Integrata con esoscheletro in acciaio: applicazione a un edificio esistente
No full textLarga parte del patrimonio edilizio italiano presenta tangibili carenze dal punto di vista energetico, strutturale ed architettonico. Ciò comporta un elevato impatto ambientale associato sia ai notevoli consumi energetici, che alla necessità di intervenire per la riparazione o demolizione e smaltimento a seguito di eventuali eventi sismici. Intervenire focalizzandosi sulle singole problematiche non è la soluzione adeguata al miglioramento delle prestazioni degli edifici, sia dal punto di vista economico che della sostenibilità, in quanto l’importanza del problema richiede misure più estese, integrate ed efficaci. Operare in modo integrato sugli edifici pianificando interventi che ne risolvano contestualmente tutte le carenze permette di superare le criticità dei tradizionali interventi disaccoppiati, garantendo il massimo dei benefici con il minimo dei costi. In questo articolo si riporta un esempio di intervento globale ed olistico, concepito in ottica Life Cycle Thinking, che prevede la realizzazione di un esoscheletro metallico esterno, costituito sia da tubolari cavi che da pannelli in lamiera, per il rinforzo strutturale di una tipologia di edifici residenziali diffusamente realizzati nel nord d’Italia negli anni ’50 e ’60. L’edificio analizzato è caratterizzato dalla presenza di muratura portante in blocchi di laterizio ad alto indice di foratura disposti con i fori in orizzontale. Le pareti murarie realizzate con questa tecnica costruttiva sollecitate per presso-flessione esibiscono un meccanismo di rottura fragile, per modestissimi valori del drift di interpiano, inferiori rispetto a quanto suggerito dalle norme per le pareti in muratura, che comporta anche la perdita di capacità portante ai carichi verticali. L’intervento di miglioramento sismico concepito per questa tipologia di edifici deve pertanto limitare gli spostamenti laterali di interpiano, mantenendo l’edificio in campo elastico per eventi sismici di alta intensità. L’efficacia della tipologia di rinforzo proposta è stata verificata per l’edificio caso studio, ubicato in un territorio di zona sismica 2. Il rinnovamento architettonico delle facciate dello stesso edificio è stato concepito sia per evidenziare il ruolo strutturale dei nuovi componenti in acciaio, sia per conservare il carattere figurativo murario che rende coerente l’edificio al suo contesto. L’intervento di efficientamento energetico prevede l’applicazione di elementi coibentanti che consentono il passaggio dalla classe energetica F alla
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
Preliminary Seismic Assessment of Braced Double Interface Rocking Walls
No full textIn recent years, many researchers have focused the attention on damage avoidance design solutions to mitigate the damage on buildings during earthquakes. To this end, rocking systems have been well established. Hybrid walls, i.e. rocking walls with additional energy dissipation, represent a valid lateral force resisting system in seismic regions, due to the limited seismic damage experienced by this system and to the self-centering ability provided by unbounded post-tensioned tendons. These systems accommodate the displacement seismic demand by the development of a single gap opening at the wall base. In recent years, some researchers have investigated the multiple rocking system concept by introducing one or more additional rocking interfaces. Herein, the double rocking concept with bracing in the building region above the second rocking interface is investigated. A case study implementing this concept is considered and the results are compared to a single rocking interface wall structure
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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