Search results for "Concrete column"
showing 8 items of 8 documents
Simplified analytical model for moment–axial force domain in the presence of shear in R.C. members externally strengthened with steel cages
2015
Equations for a hand calculation of moment–axial force domain in the presence of shear for R.C. beam/column externally strengthened with steel angles and strips are developed. The analytical derivation is made assuming, for axial load and flexure, the equivalent stress-block parameters for internal forces, considering the confinement effects induced in the concrete core by external cages both in the cases of strips or angles yielding. Limit states due to bond failure, concrete crushing and yielding of steel angles and strips in flexure and in shear, including moment-to-shear interaction, are considered. The proposed model gives results in a good agreement with available experimental data an…
Stiffness and strength of composite truss beam to R.C. column connection in MRFs
2015
Abstract The results of experimental and numerical investigations on the cyclic behavior of composite truss beam to reinforced concrete column connection of moment resisting frames are reported. The beams are constituted by a steel truss and end zone added rebar embedded within a concrete block cast in place, so that, after curing, the steel truss and the added rebar work together with the concrete matrix as reinforcement of the composite beam. Particularly, three specimens of two-span continuous beams were tested under monotonic and cyclic actions as three point bending test. With the goal to investigate about the behavior of the end zone of the beam integrated into a moment resisting fram…
Load carrying capacity of RC compressed columns strengthened with steel angles and strips
2012
Abstract In this paper a comparison between the analytical expressions for the prediction of the load carrying capacity of strengthened reinforced concrete (RC) columns with steel angles and strips is made. Expressions examined consider: the strength contribution due to the confinement effects induced by transverse strips; the composite action due to steel angles and unconfined concrete core; the strength contribution due to the composite actions of angles and concrete core taking into account that steel angles are subjected to axial force and bending moment and concrete core is confined by transverse strips. Design rules given by recent codes for the design of the strengthened columns are …
RC column externally strengthened with RC jackets
2013
In this paper the behaviour in compression of RC columns externally strengthened with concrete jacketing is analysed and a cross-section analysis of the jacketed member under axial load and bending moment is developed. The focus was to study the effect of confinement of concrete jacket on concrete core and the behaviour of compressed bars with buckling effects. Some other important aspects such as shrinkage, creep, old to new concrete surfaces and bond split effects were not included in the model because: the use of thick non-shrink grout jacket and a well-roughened surface of old-to-new concrete was supposed; long term effects were included though corrective coefficients for monolithic beh…
Simplified Model for Compressive Behavior of Concrete Columns Strengthened by Steel Angles and Strips
2010
This paper presents an analytical model to determine the compressive response of concrete members, having a square transverse cross section and reinforced with steel angles at the corners and steel strips connecting the steel angles. The model evaluates the effects of transverse strips and steel angles on confinement pressures, including strength and buckling phenomena. Compressive response was evaluated in cases of directly and indirectly loaded elements. The data produced correlate well with available experimental data.
Strength and ductility of R.C. columns strengthened with steel angles and battens
2012
Abstract In this paper the behaviour of R.C. members externally strengthened with steel angles and battens subjected to axial force and bending moment is analysed. A fibre model was utilised to predict the moment–curvature diagrams of the strengthened members on the basis of stress–strain curves of the constituent materials (confined concrete, steel bars and angles) recently derived by the author. The stress–strain curves utilised for compressed concrete were able to take into account the confinement effects induced by longitudinal (bars and steel angles) and transverse (stirrups and battens) steel reinforcements. Constitutive laws in compression for confined concrete and steel bars and ang…
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…