Search results for "Confine"

Numerical analysis of the effects of PBO-FRCM confinement on RC columns

2018

This paper presents a finite element (FE) analysis on the behavior of reinforced concrete (RC) squared and rectangular columns strengthened by PBO-FRCM, under axial force and bending moment. The modeling technique adopted for the compressive behavior of confined concrete is previously validated developing FE models for specimens of plain concrete wrapped by PBO-FRCM and comparing the numerical results with those obtained by experimental tests on squared and rectangular confined columns. Then, the model of the RC element is developed reproducing the load condition of columns in a MRF loaded by horizontal forces with constant axial load applied to the pillar during the analysis. The numerical…

COMPRESSIVE BEHAVIOR OF CONCRETE COLUMNS AXIALLYLOADED BEFORE CFRP-WRAPPING. REMARKS BY EXPERIMENTALNUMERICAL INVESTIGATION

2018

Strengthening of existing concrete columns with Fiber Reinforced Polymers (FRP) results generally in a satisfactory structural member improvement in terms of load and strain capacity. A reliable prediction of the capacity obtained by these reinforcement strategies requests a proper knowledge of the load-strain response of the confined concrete elements. However, so far, the available design methods and technical codes do not consider the effect of the possible presence of service loads at the moment of application of the reinforcement, and therefore, the compressive behavior of the concrete confined under preload is still unclear. In this paper, the effect of sustained loads on the compress…

Flexural behaviour of RC columns strengthened with steel angles and strips

2011

Cyclic axial testing of columns confined with Fiber Reinforced Cementitious Matrix

2012

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

Strengthening of Solid Brick Masonry Columns with Joints Collared by Steel Wires

2013

This work presents the results of an experimental investigation on the behavior of columns made of solid clay bricks strengthened by stainless steel wires placed in the joints. The characterization of each constituent property (bricks, mortar, and steel wires) and the compression tests on columns show the effectiveness of the proposed strengthening technique with the result of increased ductility of brick columns. From the analytical point of view a model is proposed which gives the response in terms of the stress-strain curve, by taking into account the presence of steel wires placed in the joints, and the consequences on the effective confinement pressure with the following resulting enha…

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 experimental study on the compressive behaviour of calcarenite masonry columns wrapped by fiber reinforced mortar wraps

2018

The use of Fiber Reinforced Cementitious Mortar (FRCM) systems for structural retrofitting of masonry structures has become increasingly popular in the last years, due to the capability of this technique in overcoming some of the drawbacks related to the adoption of resin-based composites. In fact, FRCM systems ensure good compatibility between the reinforcing layers and the substrate, achieving also the removability requirement, which is of fundamental importance for historical constructions. Recent research studies focused on the mechanical performance of FRCM materials, by studying its tensile behaviour and bond between the strengthening layer and masonry, pointing out as failure is alwa…

Simulating CFRP-confinement of concrete bridge piers under sustained loads: evaluation of the compressive capacity

2018

The present paper deals with the evaluation of the compressive behaviour of circular concrete columns strengthened with carbon fiber reinforced polymers (CFRP) under different levels of sustained loads and subsequently loaded until failure. The aim was to compare the effect of existing stress/strain states on the axial load-strain response of bridge piers after strengthening under sustained loads. An experimental investigation was carried out on circular plain concrete columns loaded up to low, medium and high ratios of the concrete compression capacity before the application of the CFRP-confinement. After the strengthening process, the columns were loaded until failure, comparing the resul…