Search results for " Jack"
showing 10 items of 45 documents
Development of a software package with GUI for the evaluation of monolithicity factors of RC jacketed columns
2023
The design of reinforced concrete (RC) jacketing for retrofitting substandard columns is a common practice when approaching the structural rehabilitation design of existing structures. In this framework, international technical codes suggest to assume the hypothesis of monolithic section and finally affecting the deduced performances by some empirical factors, known in the literature as monolithicity factors. The assessment of these coefficients is a difficult task, and only some rough assumptions can be found in the modern codes. This paper presents the development of a software package able to perform the static non-linear analysis of RC jacketed columns and evaluating the actual value of…
A simplified method for ductility calculation in RC jacketed columns
2015
Reinforced concrete (RC) jacketing is a common method to retrofit existing columns with poor structural performance. It can be applied in two different ways: if the continuity of the jacket is ensured, the axial load of the column can be transferred to the jacket, which will be directly loaded; conversely, if no continuity is provided, the jacket induces only confinement action. In both cases the strength and ductility evaluation is rather complex, due to the different physical phenomena included, such as confinement, composite action core-jacket, preload, buckling of longitudinal bars. Although different theoretical studies have been carried out to calculate the confinement effects, a prac…
Assessment of the load carrying capacity of reinforced concrete columns strengthened by steel cages Specificità nella valutazione della capacità port…
2018
In the present paper, a selected review of the most relevant analytical models provided for the evaluation of the con-finement properties of Steel Jacketed RC columns is discussed. The reliability of the models is tested by comparing the analytical predictions of the load capacity with experimental results available in the literature depending on the type of mechanical end-connections. Moreover, new considerations regarding the application of the steel jacketing on columns while loaded are faced by experimental investigation
FE modeling of Partially Steel-Jacketed (PSJ) RC columns using CDP model
2018
This paper deepens the finite element modeling (FEM) method to reproduce the compressive behavior of partially steel-jacketed (PSJ) RC columns by means of the Concrete Damaged Plasticity (CDP) Model available in ABAQUS software. Although the efficiency of the CDP model is widely proven for reinforced concrete columns at low confining pressure, when the confinement level becomes high the standard plasticity parameters may not be suitable to obtain reliable results. This paper deals with these limitations and presents an analytically based strategy to fix the parameters of the Concrete Damaged Plasticity (CDP) model. Focusing on a realistic prediction of load-bearing capacity of PSJ RC column…
An interface model for the analysis of the compressive behaviour of RC columns strengthened by steel jackets
2019
Steel jacketing technique is a retrofitting method often employed for static and seismic strengthening of existing reinforced concrete columns. When no continuity is given to angle chords as they cross the floor, the jacket is considered “indirectly loaded”, which means that the load acting on the column is transferred partially to the external jacket through interface shear stresses. The evaluation of load transfer mechanism between core and jacket is not straightforward to be modeled, due to the absence of knowledge of a proper constitutive law of the concrete-to-steel interface and to the difficulties in taking into account the mechanical nonlinearities of materials. This paper presents …
Steel jacketing of RC columns: Reliability of capacity laws for concrete
2016
In the seismic assessment of framed R.C. structures reinforced by steel angles and battens (steel jacketing) the use of proper confinement models for concrete is still a main topic. Really, the capacity of reinforced concrete columns under concentric and eccentric loads strongly depends on confinement exerted by the external reinforcement. Further a proper attribution of concrete stress-strain laws allows obtaining reliable estimations of inelastic capacity of reinforced elements. Moreover the presence (or not) of connections of the angles with the end joints influences their capacity to support vertical loads. In the two cases the mechanical models have to account for buckling or frictiona…
Emily Nevill Jackson e le Arti Decorative in Sicilia
2022
Through the study of sources and their contextualisation with the panorama of artistic literature of the time, the article aims to present the figure of Emily Nevill Jackson, an English scholar of the Decorative Arts active in London between the end of the 19th century and the first thirty years of the 20th century. Jackson can be counted among the many women scholars who published in the main periodicals of the sector during that period, contributing to a comprehensive representation of the international reality related to the specific sector of Decorative Arts, in the wake of the influence of Ruskin and Morris’ thought. Jackson, in particular, in the final part of her career made a trip t…
Sicily's Prime - Il viaggio nelle Arti Decorative siciliane di Emily Nevill Jackson
2022
“A student in Sicily” by Emily Nevill Jackson, published in 1926, represents the first real general survey of Sicilian Decorative Arts. In it, the author describes in detail works, typologies, materials, techniques and collections with a meticulousness and precision that would only be fully reflected and scientifically formulated in later studies. After reconstructing the figure of the scholar, the book examines Jackson's text on the works of Decorative Arts, contextualising it with the most recent scientific studies on the works themselves.
Numerical Calibration of a Simplified Model for FRP Confinement of Columns
2018
This paper presents the calibration of a simplified analytical model for concrete columns confined by fiber reinforced polymer (FRP) jackets. The model allows evaluating the increase of strength, ductility and dissipated energy without defining the lateral confinement pressure and it can be easily extended for the assessment of FRP confinement in design applications. This model was obtained by a simplified procedure based on the best fit of experimental data available in the literature and the coefficient of determination (R2) was evaluated in order to estimate the accuracy of the regression analysis. A numerical database resulting from finite element (FE) analyses was compiled and reported…
Simplified analytical models for compressed concrete columns confined by FRP and FRCM system
2017
In order to consider the response of concrete columns confined by FRP and FRCM system, proper models have to be formulated. In this context the present paper shows a generalized criterion for the determination of the increase in strength, in ductility and in dissipated energy for varying corner radius ratio of the cross section and fiber volumetric ratio. The procedure is based on the best fitting of several experimental data and unlike the usual empirical approaches available in the literature, the proposed technique relates the confinement effectiveness to a single parameter representative of the relative stiffness between the original concrete core and the reinforcement system. Furthermo…