Lateral force-displacement ductility relationship of non-ductile squat RC columns rehabilitated using FRP confinement

2007 ◽  
Vol 25 (1) ◽  
pp. 75-89 ◽  
Author(s):  
K. Galal
Keyword(s):  
Lateral Force ◽  
Rc Columns ◽  
Displacement Ductility ◽  
Frp Confinement ◽  
Relationship Of ◽  
Force Displacement

Semi-inverse method for predicting stress–strain relationship from cone indentations

2003 ◽  
Vol 18 (9) ◽  
pp. 2068-2078 ◽  
Author(s):  
A. DiCarlo ◽  
H. T. Y. Yang ◽  
S. Chandrasekar
Keyword(s):  
A Priori ◽  
Model Material ◽  
Material Behavior ◽  
The Finite Element Method ◽  
Stress Strain ◽  
Indentation Tests ◽  
Strain Relationship ◽  
Initial Force ◽  
Relationship Of ◽  
Force Displacement

A method for determining the stress–strain relationship of a material from hardness values H obtained from cone indentation tests with various apical angles is presented. The materials studied were assumed to exhibit power-law hardening. As a result, the properties of importance are the Young's modulus E, yield strength Y, and the work-hardening exponent n. Previous work [W.C. Oliver and G.M. Pharr, J. Mater. Res. 7, 1564 (1992)] showed that E can be determined from initial force–displacement data collected while unloading the indenter from the material. Consequently, the properties that need to be determined are Y and n. Dimensional analysis was used to generalize H/E so that it was a function of Y/E and n [Y-T. Cheng and C-M. Cheng, J. Appl. Phys. 84, 1284 (1999); Philos. Mag. Lett. 77, 39 (1998)]. A parametric study of Y/E and n was conducted using the finite element method to model material behavior. Regression analysis was used to correlate the H/E findings from the simulations to Y/E and n. With the a priori knowledge of E, this correlation was used to estimate Y and n.

Seismic assessment of reinforced concrete columns with short lap splices

2021 ◽  
pp. 875529302199483
Author(s):  
Eyitayo A Opabola ◽  
Kenneth J Elwood
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Failure Modes ◽  
Concrete Columns ◽  
Seismic Assessment ◽  
Rc Columns ◽  
Lap Splices ◽  
Displacement Response ◽  
Force Displacement ◽  
Probable Failure

Existing reinforced concrete (RC) columns with short splices in older-type frame structures are prone to either a shear or bond mechanism. Experimental results have shown that the force–displacement response of columns exhibiting these failure modes are different from flexure-critical columns and typically have lower deformation capacity. This article presents a failure mode-based approach for seismic assessment of RC columns with short splices. In this approach, first, the probable failure mode of the component is evaluated. Subsequently, based on the failure mode, the force–displacement response of the component can be predicted. In this article, recommendations are proposed for evaluating the probable failure mode, elastic rotation, drift at lateral failure, and drift at axial failure for columns with short splices experiencing shear, flexure, or bond failures.

Application of the MCC Model on 2-D Finite Element Analyses for the Assessment of Pipe-Soil Lateral Response

2019 ◽  
Author(s):  
Tianna Bloise Thomaz ◽  
Daniel Carneiro ◽  
Gilberto Bruno Ellwanger ◽  
Leonardo Sant’Anna do Nascimento
Keyword(s):  
Finite Element ◽  
Simulation Models ◽  
Lateral Force ◽  
Soil Behavior ◽  
Soil Plasticity ◽  
Lateral Response ◽  
Modified Cam Clay ◽  
Full Scale Tests ◽  
Subsea Pipelines ◽  
Force Displacement

Abstract The assessment of the pipe-soil interaction is an area of continuous research, either by the application of small- and full-scale tests in the attempt to reproduce accurately the interaction of the pipelines and the soil, or by the development of sophisticated numerical simulation models accounting for different sources of nonlinearities. Motivated to investigate the interaction between subsea pipelines and the soil, with focus in the response under lateral loading, 2-D finite element numerical simulations have been developed applying soil plasticity mechanisms through the extended maximum distortion strain energy criteria [1] and critical state concept [2]. The modified-cam-clay MCC model has been adopted to simulate the soil behavior in large deformations, aiming to numerically reproduce site conditions for selected pipelines ranging from 12 in to 18 in. The results are presented in terms of the lateral force-displacement curves for numerically representative drained and undrained cases. For the simulations investigated in this work, the agreement of the numerical results with the analytical breakout lateral resistances obtained from the SAFEBUCK guideline [3] formulations have been confirmed for cases where the ratio of initial pipe embedment and pipe diameter is below 0.4.

Dynamics of Deformable Fractal Surface in Contact with Harmonically Excited Rigid Flat

2017 ◽  
Vol 7 (2) ◽  
pp. 38-62
Author(s):  
Tamonash Jana ◽  
Anirban Mitra ◽  
Prasanta Sahoo
Keyword(s):  
Rough Surface ◽  
Dynamic Properties ◽  
Element Model ◽  
Harmonic Excitation ◽  
System Response ◽  
Fractal Surface ◽  
Fractal Rough Surface ◽  
Mass Damper ◽  
Relationship Of ◽  
Force Displacement

Dynamics of contact between a deformable fractal rough surface and a rigid flat is studied under harmonic excitation to the flat surface. Fractal surface is generated from the modified Weierstrass-Mandelbrot function and is imported to ANSYS to construct the finite element model of the same. A parameter called ‘nonlinearity exponent', is obtained from the force-displacement relationship of the rough surface and is used to find out the dynamic properties of the contacting interface using single spring-mass-damper model. The effect of variation in surface roughness and material properties on the system response is analyzed. The system exhibits superharmonic responses for different values of the nonlinearity exponent. The phase plot and time-displacement plots for the system are also furnished.

Effects of Midlayer Used in FRP Confinement of RC Columns

2019 ◽  
Vol 23 (2) ◽  
pp. 04019002
Author(s):  
Hamid Karimizadeh ◽  
Mohammad Reza Eftekhar ◽  
Davood Mostofinejad
Keyword(s):  
Rc Columns ◽  
Frp Confinement

Seismic response of structural walls: recent developments

2001 ◽  
Vol 28 (6) ◽  
pp. 922-937 ◽  
Author(s):  
T Paulay
Keyword(s):  
Reinforced Concrete ◽  
Seismic Response ◽  
Seismic Design ◽  
Limit State ◽  
Lateral Force ◽  
Structural Walls ◽  
Structural Class ◽  
Response Component ◽  
Displacement Ductility ◽  
Ductility Capacity

It is postulated that for purposes of seismic design, the ductile behaviour of lateral force-resisting wall components, elements, and indeed the entire system can be satisfactorily simulated by bilinear force–displacement modeling. This enables displacement relationships between the system and its constituent components at a particular limit state to be readily established. To this end, some widely used fallacies, relevant to the transition from the elastic to the plastic domain of behaviour, are exposed. A redefinition of stiffness and yield displacement allows more realistic predictions of the important feature of seismic response, component displacements, to be made. The concepts are rational, yet very simple. Their applications are interwoven with the designer's intentions. Contrary to current design practice, whereby a specific global displacement ductility capacity is prescribed for a particular structural class, the designer can determine the acceptable displacement demand to be imposed on the system. This should protect critical components against excessive displacements. Specific intended displacement demands and capacities of systems comprising reinforced concrete cantilever and coupled walls can be estimated.Key words: ductility, displacements, reinforced concrete, seismic design, stiffness, structural walls.

Axial Compression Test of RC Columns Consolidation with BFRP

2012 ◽  
Vol 166-169 ◽  
pp. 881-884
Author(s):  
Bao Rong Huo ◽  
Xiang Dong Zhang
Keyword(s):  
Comparative Study ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Calculation Formula ◽  
Rc Columns ◽  
Displacement Ductility ◽  
Rc Column ◽  
Ductility Factor ◽  
Increase Rate ◽  
The Comparative Study

12 RC columns were made, including nine RC columns wrapped with BFRP, three RC columns without any reinforcement, to conduct the comparative study of axial compression. The result shows that the bearing capacity of the RC columns reinforced with the fibers increases obviously.The displacement ductility factor increases, but its increase rate becomes slow with increasing layers of fiber cloth, so the most economical layer number is 3. Based on the confinement mechanism of FRP cloth and the calculation formula of the bearing capacity for common RC column, the formula of the bearing capacity for reinforced RC column with BFRP cloth is proposed. The result of calculation basically tallies with the number in experiment.

PERFORMANCE ADVANCEMENT OF RC COLUMNS BY APPLYING BASALT FRP COMPOSITES WITH NSM AND CONFINEMENT SYSTEM

2013 ◽  
Vol 07 (02) ◽  
pp. 1350007 ◽  
Author(s):  
LINING DING ◽  
GANG WU ◽  
SHENYIN YANG ◽  
ZHISHEN WU
Keyword(s):  
Performance Enhancement ◽  
Load Capacity ◽  
Basalt Fiber ◽  
Chemical Properties ◽  
Strength Degradation ◽  
Rc Columns ◽  
Near Surface ◽  
Displacement Ductility ◽  
Frp Composites ◽  
Yield Displacement

Basalt fiber reinforced polymer (BFRP) composites are regarded as promising structural strengthening material due to their environmental friendly and superior mechanical and chemical properties. In order to enhance the overall seismic performance of RC columns, a strengthening system is developed by applying BFRP composites with both near surface mounted (NSM) and confinement approaches. The variables taken into account consisted of the diameters and anchorage lengths of BFRP bars, as well as the confinement amounts of BFRP sheets. A total of eight column specimens including one control were tested subjected to simultaneous axial compression and cyclic bend. The structural performance such as load capacity, displacement, ductility, stiffness degradation, energy dissipation capacity, curvature and post-yield stiffness were investigated. The test results indicate that the combination of NSM and confinement techniques contributes to the comprehensive performance enhancement of RC columns, which lies in (1) constantly enlarging diameters of BFRP bars increases the yield and peak loads, the ultimate displacement, the initial and post-yield stiffness as well as the ductility, whereas it has no obvious influence on the yield displacement; (2) longer bonding length results in higher seismic performances although it makes no changes to the yield displacement, the post-yield stiffness, and the degradation of strength and stiffness as well; (3) the adoption of BFRP confinement significantly improves the ductility and the strength degradation performance; (4) the largest post-yield stiffness can be achieved by enlarging diameter to 12 mm, whereas the ductility and the strength degradation characteristics deteriorate due to the weakness of interfacial bonding between BFRP bars and concrete.

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