1,721,004 research outputs found
Indagini teoriche e sperimentali su dissipatori ad attrito per edifici in acciaio in zona sismica
No full textThe present paper presents the results of experimental analyses carried out to study the behaviour of slotted bolted connections (SBC) as friction steel dampers. The devices consist of bolted joints with slotted holes, which can be used in both steel and RC framed structures or, alternatively, into beam-column and column-foundation joints.
The most suitable configurations to increase friction are investigated utilizing steel S355J0 plates and class 10.9HV high-strength bolts, under controlled pre-load and considering different types of surface treatment.
Experimental tests are carried out making use of a universal testing machine, which allows mak-ing displacement-controlled tests. Once the pre-load frictional force is reached, the plates begin to slide each other through the hollow holes, dissipating energy through friction.
The paper shows the results obtained during the tests in terms of frictional force vs. displacement, friction coefficient values and variation pre-load in bolts. The results are compared with the theo-retical values derived from the calculation
Shear-to-Moment Interaction in Glass Beams with Open Cross Sections
No full textAn experimental investigation regarding the flexural behavior of glass beams with a length of 1,200 mm and rectangular, T-shaped, or I-shaped cross sections is presented and discussed. T-shaped and I-shaped cross sections were obtained by assembling laminated glass (LG) panels of 200 mm depth and 12.76 mm thickness through an acrylic adhesive. Three specimens for each series investigated were tested in flexure, focusing on the flexural and shear response of beams through the determination of the load-deflection curves and crack patterns at rupture. The shear span to depth ratio a/d was 2.25, which is a very low value, and interaction of shear and bending moment occurred during the tests. An analytical model is presented for a preliminary design of composite glass beams. The model, able to predict the load-deflection response of the beam, includes limit states attributable to flexure, glass web crushing, and glue shear failure. The experimental data generated, confirmed by numerical analyses, show the effectiveness of the analytical model to reproduce experimental results
Footbridge design in Viale Regione Siciliana in Palermo
No full textThe paper investigates some solutions designed by the author, as structural consulting engineer of the municipal administration of Palermo, to build a footbridge over Viale Regione Siciliana, in the section between Via Perpignano and Viale Leonardo Da Vinci.
The pedestrian underpass put in place in the 1990s, during the construction of the new road, was considered to be unsatisfactory for pedestrian safety due to possible robberies. In the last few years the administration has been oriented towards the creation of footbridges, designed to be accessible to the differently abled too. This is possible in relationship to the definitive abandonment of the project of a flyover.
The paper shows some designs for the footbridges from Piazza John Lennon to Piazza Einstein developed by D. Perroult and refers to other structures in line with Via Palmerino and Via Santa Maria di Gesù. All the bridges have steel structures, usually with reticular configuration.
With reference to the Perpignano footbridge we describe the problems connected to the localization of the footbridge for which two solutions were considered:
i) near Via Perpignano, passing over the new traffic circle
ii) near Via Nazario Sauro, almost halfway along the section between the two consecutive subways.
Both solutions used structural steel. Specifically, the two definitive versions utilized cable-stayed systems.
In the first case the cables are attached to a central tower; while in the second case, which was approved, the cables are anchored to an asymmetrical tower situated below the road.
The system used is a tubular steel structure having a hexagonal transversal section, sustained by 4 couples of cables.
The paper discusses some design questions of a general character and shows the executive project of the footbridge.
Keywords: steel structures, cable-stayed systems, footbridges, wind load
Nicolò Scibilia - una vita per le costruzioni 1945-1999
No full textL’esposizione comprende un arco temporale di circa un quarantennio e traccia un quadro sufficientemente completo di Nicolò Scibilia, ingegnere progettista e imprenditore.
La sua vasta attività comprende un primo periodo di circa dieci anni dedicato prevalentemente alla ricostruzione del paese distrutto dalla guerra. In tale ambito si collocano gli importanti interventi sulle chiese di S, Francesco d’Assisi e dell’Olivella gravemente danneggiate dai bombardamenti del 1943.
Seguirono interventi di costruzione di nuovi edifici residenziali sulla base del Piano di Ricostruzione e di piani di lottizzazione.
Ampio spazio è dedicato alle progettazioni per l'edilizia religiosa, scolastica e assistenziale. Tuttavia rivestono carattere di eccellenza gli interventi progettati ed eseguiti per la trasformazione di numerosi edifici, al fine di renderli idonei alle attività commerciali. Infine, si riportano i progetti di edifici civili e industriali
Progetto di Strutture in acciaio per le nuove costruzioni e per gli interventi di consolidamento. IV Edizione
No full textThe book is a state of the art summary of recent development in the behavior, analysis and design of steel and composite structures.
The book provides advanced students, researchers al professionals in civil and structural engineering with the basic principles upon which the modern codes are based. In the first part, the materials, the actions and the sectional behavior are analyzed on the base of the limit state theory.
Then the connections (bolted and welded)and the stability effects are examined.
In this way is possible speak about seismic performance, retrofitting an refurbishment of existing buildings, referring to the italian rules, to the european codes EC3, EC4 and to the
AISC rules
Isolamento sismico di serbatoi di impianti chimici a Priolo Gargallo (SR)
No full textI serbatoi di stoccaggio degli impianti petrolchimici costituiscono una seria minaccia alla salvaguardia dell’ambiente, a causa delle conseguenze disastrose derivanti da un loro collasso, come messo in luce dai recenti eventi catastrofici. Pertanto, l’ENEA ed il GLIS hanno intrapreso un’intensa attività di ricerca e di informazione per sensibilizzare l’opinione pubblica su tali importanti pericoli.
Tra le cause più frequenti di collasso si citano le azioni sismiche, particolarmente rilevanti in zone prossime a faglie attive, come risulta quella di Priolo Gargallo, in provincia di Siracusa, già sede di sismi distruttivi.
I danni sono stati spesso ingigantiti dagli incendi sviluppatisi in seguito ai sismi. Pertanto, negli ultimi anni si sono realizzati numerosi interventi atti ad incrementare la sicurezza di tali strutture nei confronti delle azioni sismiche. Tra questi l’isolamento sismico costituisce una delle tecniche più efficaci per garantire adeguati margini di sicurezza.
Nella presente nota si riferisce sugli interventi eseguiti a Priolo Gargallo (SR), ove sono stati adottati dispositivi di isolamento del tipo a pendolo ad attrito, in grado di resistere anche al calore che si potrebbe sviluppare in caso di incendi, premettendo alcune nozioni sull’isolamento sismico ed in particolare sul funzionamento del pendolo ad attrito
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
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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