Search results for " Concrete"
showing 10 items of 190 documents
Cupole in cemento armato in Sicilia occidentale nella prima metà del Novecento
2014
The paper intends to examine through three case studies the change introduced by the technology of reinforced concrete in the construction of domes. After a brief description of the geometric and architectural characteristics of reinforced concrete domes, the study focuses on three interventions, for which a considerable archival documentation was collected. Chronologically the first intervention is related to the construction of the dome of the mother-church of Bisacquino (1923-25), built on the basis of the architectural project and under the direction of the engineer Pietro Scibilia. The second concerns the reconstruction of the dome of Sant’Ignazio martire all'Olivella church in Palermo…
Assessment and strengthening of reinforced concrete bridges with half-joint deterioration
2022
Existing Niagara-type concrete cantilever bridges, which in Italy are called Gerber bridges, suffer from degradation due to reinforcement corrosion and a consequent reduced load-bearing capacity. The assessment of these structures is therefore an important part of the procedures for analyzing the state of existing bridges and any interventions required for their retrofitting. In particular, safety against failure of the half-joint must be evaluated with respect to the behavior of the entire bridge and its state of conservation, determining what the conditions are that lead to failure, in terms of loads, state of stress, and possibly cracking state. This evaluation has to be carried out cons…
Calcestruzzi rinforzati con fibre di PET. Sperimentazioni sull'impiego delle fibre di PET provenienti dalla raccolta differenziata nella produzione d…
2013
La sperimentazione esposta tratta dell’impiego di fibre di PET, ricavate dal semplice taglio di contenitori per bevande, nel rinforzo di calcestruzzi destinati anche a impieghi strutturali. Indaga la durabilità delle fibre in ambiente fortemente basico e le caratteristiche meccaniche di calcestruzzi rinforzati con differenti dosaggi di fibre. Le osservazioni al microscopio elettronico a scansione (SEM) di fibre di PET immerse per 13 giorni a 65°C in acqua distillata e in due soluzioni fortemente basiche mostrano la buona durabilità delle fibre in soluzione 0,103 M di NaOH, che simula la basicità della soluzione acquosa che permea la matrice cementizia. L’influenza delle fibre e del loro dos…
Il modulo elastico statico e dinamico del calcestruzzo
2012
Some recent results on the compressive and flexural behaviour of composite members
2005
Experiemntal results from compression and flexural tests on steel tubulare columns having circular or rectangular transverse cross-section and infilled with plain or fiber reinforced concrete (FRC) are analysez. for composite members differenti lengths and different dimensions of transverse cross-section were considered in order to assess the influence on behavior in flexure and in compression.The fiber investigated with different percentage were syntetic, carbon and deformed steel fibers. The constituent materials were characterised through compressive and split tests on conconcrete cylinders. Load.shortning and load-delection curves were determined including the sotnening response. Simpli…
¿Cabe hablar de una «generación de la crisis»? Discusión en torno a una noción sobreexplotada
2018
This article states that nowadays there is an overuse (or a misuse) of the «Generation» idea. The discussion among many authors over the «Generation of crisis» concept suggests that it is useful to outline the characteristics of the target of population of the collective of youth who are mainly affected by the economic and social crisis over the past years. Nevertheless, through analyzing the meanings of the «Generation of Crisis» made by Mannheim, Ortega and other classic authors, it is clear that the social class approach together with the generational one are needed to define this concrete concept. The conclusion of the articleis that both approaches are seen as underpinning their utilit…
Towards resilient cities: Advancements allowed by a multi-criteria optimization tool to face the new challenges of European Union’s climate and energ…
2019
Abstract The United Nations as well as the European Union are strongly committed in promoting a transition towards more sustainable and resilient cities. Indeed, they are increasingly affected by different types of threats, among which the natural ones such as earthquakes, fires, and floods (shocks) and climate variability (stresses). Cities are quite often unable to cope with the adverse effects of such natural hazards. This circumstance leads to the need of introducing resilience-related criteria (besides commonly used sustainability indicators) in decision-making processes. This paper investigates at which extent the inclusion of such new indicators, within multi-criteria assessment tool…
Il calcestruzzo poroso per il miglioramento delle condizioni di stabilità dei pendii sede di falda idrica
2022
Reduction of pore water pressures is a useful strate-gy to improve the stability conditions of slopes. Deep draining trenches can be used for this scope. For the realisation of deep trenches, the usual con-ventional construction techniques are not adequate and the use of adjacent vertical panels, built by means of the methods well established for dia-phragm walls, is necessary. However, unbonded ma-terials (i.e. gravels) cannot be used, since the excava-tion of a panel adjacent to already built ones will cause instability. For this scope a bonded material such as the pervious concrete can be used. It must have high permeability, filtering capacity in order to prevent the internal erosion of…
La resistenza di interfaccia calcestruzzo poroso-terreni a grana fina per il consolidamento di pendii mediante trincee drenanti profonde
2022
Le trincee drenanti profonde rappresentano uno dei metodi più efficaci per la mitigazione del rischio da frana, in pendii con falda idrica. Esse sono realizzate mediante pannelli o pali secanti. Il riempimento è costituito di calcestruzzo poroso o materiale granulare. Se le trincee sono adeguatamente “innestate” nel terreno stabile e il materiale di riempimento ha sufficiente resistenza e rigidezza come il calcestruzzo poroso, si ha ulteriore in-cremento di resistenza a taglio per effetto shear keys, oltre a quello derivante dalla riduzione delle pressioni in-terstiziali. L’incremento di resistenza è dovuto sia alla resistenza all’interfaccia calcestruzzo–terreni sia a quella intrinseca del…
Failure Load and Collapse Mode of an RC Beam in a Large Collapsed Roof
2021
The present work focused on the determination of the collapse load and of the failure mode of a collapsed framed structure constructed in the South of Italy and failed in 2004 under its self-weight. Information available was the results on extensive experimental test campaign, for the determination of mechanical properties of concrete and steel bars of beams, floors and columns involved in the failure. Moreover, draws of original design with construction details and design rules valid in Italy at the time of construction were found. A simple monodimensional beam model for prediction of load-deflection curve, able to include degradation of constituent materials (concrete, steel and bond) was…