Search results for "Retrofit"
showing 10 items of 132 documents
Analysis-oriented stress–strain model of CRFP-confined circular concrete columns with applied preload
2018
The compressive behavior of FRP-confined concrete is a current issue in the field of structural retrofitting. The available models well predict the stress–strain behavior under monotonic and cyclic loads. However, in the practical applications, columns that need an increasing of bearing capacity are often strengthened under serviceability load conditions, with a stress and strain state that could change the response of the reinforced systems with respect to the case of the unloaded state. In this paper, the compressive behavior of circular FRP-confined concrete columns with preload is analyzed with the introduction of a modified analysis-oriented model. Differently from the classical formul…
Compressive behaviour of eccentrically loaded slender masonry columns confined by FRP
2018
Abstract Fibre Reinforced Polymer (FRP) confinement represents an effective tool for retrofitting masonry piers or columns enhancing their structural performance. This technique has been widely studied in the literature mainly with reference to short columns, while no extensive information is available on the influence of second order effects on its efficacy in case of slender members. Within this framework, the presented study concerns a simplified method able to assess the effects of FRP confinement on the compressive behaviour of slender masonry columns. A proper constitutive law of FRP confined masonry in compression is adopted for performing a sectional analysis, in which also consider…
Analytical modelling of force transmission in axially loaded RC columns with indirectly loaded jackets
2019
Abstract Concrete and steel jacketing are common strengthening techniques for reinforced concrete (RC) columns subjected to axial loads. In the most of cases the external jacket is made leaving gaps between the strengthening layer and the slabs, avoiding to carry directly a portion of the load. In this way, the external jacket induces a confinement pressure on the inner column, and its beneficial effect is due to the increase of strength and ductility. However, shear stresses develop on the interface between the column and consequently, the external jacket can be considered indirectly loaded. It sustains a portion of the axial load, which depends by the value of the axial shortening, relati…
Nonlinear Analysis of Reinforced Concrete Frames: Safety Evaluation and Retrofitting Techniques
Optimal design algorithm for seismic retrofitting of RC columns with steel jacketing technique
2020
Abstract Steel jacketing (SJ) of beams and columns is widely employed as retrofitting technique to provide additional deformation and strength capacity to existing reinforced concrete (RC) frame structures. The latter are many times designed without considering seismic loads, or present inadequate seismic detailing. The use of SJ is generally associated with non-negligible costs depending on the amount of structural work and non-structural manufacturing and materials. Moreover, this kind of intervention results in noticeable downtime for the building. This paper presents a new optimization framework which is aimed at obtaining minimization of retrofitting costs by optimizing the position an…
Risk of failure for the salso river railroad steel bridge
2020
Abstract The degradation state of railroad steel bridges is one of the most important and difficult aspects to be interpreted. The use of steel bridges started from 1900, and they are still in service today as railroad bridges. The case study examined was that of a bridge railroad steel bridge having a total length of 112 m and constituted by three isostatic, reticular beams having a Pratt type composition. The substructures (two shoulders and two intermediate piles) are in masonry with a reinforced concrete beam in the upper portion. The structure (steel bridge and piers) is in a degraded state. To determine the degradation level, non-destructive and partially destructive tests were carrie…
Supporting public decision process in buildings energy retrofitting operations: the application of a Multiple Criteria Decision Aiding model to a cas…
2020
Abstract The challenge of promoting sustainable cities and reaching the objectives developed by the European Green Deal includes the renovation of the building sector, as it is responsible for 40% of energy consumption in Europe. Regional or local public administrations have to allocate their financial resources for improving the energy performances of their building stock and to face a multidimensional problem, where different aspects – such as energy efficiency, financial-economic feasibility and environmental protection – have to be harmonized. The present study proposes a Multiple Criteria Decision Aiding model, which includes the ELECTRE TRI-nC method, for supporting the public decisio…
Resilience in small urban centers with a strong historical connotation
2015
La resilienza della città storica, misurata dagli eventi rispetto a calamità naturali e fenomeni emergenziali, si presenta spesso al di sopra di qualunque aspettativa. Soprattutto quando principio insediativo, trasformazioni consequenziali a calamità e ridondanze hanno di fatto aumentato la coping capacity e la capacity of response del costruito storico rendendole elevate e di significato. Nonostante ciò la necessità di implementazione di nuove qualità, nell’ottica di riappropriazione dei patrimoni urbani disseminati nel territorio e spesso abbandonati o poco popolati, pone il bisogno di retrofit, manutenzione e misure gestionali che incrementino sicurezza e resilienza. Potendosi indubbiame…
Energy retrofit of a single-family house: Life cycle net energy saving and environmental benefits
2013
Abstract When a building undergoes a retrofit project, the goal of assessing energy and environmental performances of retrofit actions is a complex matter. Building and its environment are complex systems in which all sub-systems are strongly interdependent and influence the overall efficiency performance. In the following paper, starting from a literature review of building life-cycle studies, the authors highlight that there is a strong interplay among all the phases of a building life-cycle, as each one can affect one or more of the others. In detail, starting from the results of a “cradle to grave” life cycle study of an existing Mediterranean single-family house, a set of retrofit acti…
Recupero e valorizzazione del quartiere Medaglie d’Oro attraverso l’utilizzo della vegetazione
2014
Lo stock edilizio costruito a partire dal secondo dopoguerra, che ha profondamente modificato durante il secolo scorso l’aspetto della città di Palermo, mostra oggi visibili segni di degrado e basse caratteristiche di efficienza energetica. In particolare, per il comparto della residenza sociale, risultano ancora molto carenti le politiche e gli strumenti pubblici per la riqualificazione energetica a scala di quartiere e di edificio. A partire da queste considerazioni è stata messa a punto una metodologia innovativa per la verifica dell’efficacia di interventi di retrofit energetico in cui la vegetazione occupa un ruolo distintivo per la mitigazione del microclima e l’ottimizzazione del com…