Modeling The Post Shear Failure Behavior Of Reinforced Concrete Columns
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Modeling The Post Shear Failure Behavior Of Reinforced Concrete Columns
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Author : Matthew Ronald LeBorgne
language : en
Publisher:
Release Date : 2012
Modeling The Post Shear Failure Behavior Of Reinforced Concrete Columns written by Matthew Ronald LeBorgne and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
Numerous reinforced concrete buildings vulnerable to earthquake induced collapse have been constructed in seismic zones prior to the 1970s. A major contributor to building collapse is the loss of axial load carrying capacity in non-seismically detailed columns. Experimental investigations have shown that non-seismically detailed columns will only experience axial failure after shear failure and subsequent lateral shear strength degradation have occurred. Therefore, column shear failure and degrading behavior must be modeled accurately before axial collapse algorithms can be properly implemented. Furthermore, accurate modeling of the degrading lateral-load behavior of columns is needed if lateral load sharing between structural elements is to be assessed with reasonable accuracy during seismic analyses. A calibrated analytical model was developed that is capable of estimating the lateral strength degrading behavior of RC columns prone to shear failure. Existing analytical models poorly approximate nonlinear column behavior and require several nonphysical damage parameters to be defined. In contrast, the proposed calibrated model provides the engineering community with a valuable tool that only requires the input of column material and geometric properties to simulate column behavior up to loss of lateral strength. In developing the model, a database of RC columns was compiled. Parameters extracted from database column-tests were scrutinized for trends and regression models relating damage parameters to column physical properties and boundary conditions were produced. The regression models were implemented in the degrading analytical framework that was developed in this project. Two reinforced concrete columns exhibiting significant inelastic deformations prior to failing in shear were tested in support of the analytical work. A newly developed Vision System was used to track a grid of targets on the column face with a resolution of three-thousands of an inch. Surface column deformations were measured to further the understanding of the fundamental changes in column behavior that accompany shear and axial failure and validate the proposed analytical model. This research provides the engineering community with an analytical tool that can be used to perform nonlinear dynamic analysis of buildings that are at risk of collapse and help engineers improve retrofit techniques. Further insight into shear behavior attained through this project is an important step toward the development of better shear and axial degradation models for reinforced concrete columns.
Modeling Of Inelastic Behavior Of Rc Structures Under Seismic Loads
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Author : P. Benson Shing
language : en
Publisher: ASCE Publications
Release Date : 2001-01-01
Modeling Of Inelastic Behavior Of Rc Structures Under Seismic Loads written by P. Benson Shing and has been published by ASCE Publications this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001-01-01 with Technology & Engineering categories.
Proceedings of the U.S.?Japan Seminar on Post-Peak Behavior of Reinforced Concrete Structures Subjected to Seismic Loads: Recent Advances and Challenges on Analysis and Design, held in Tokyo and Lake Yamanaka, Japan, October 25-29, 1999. Sponsored by the National Science Foundation, U.S.A.; Japan Society for the Promotion of Science; Japan Concrete Institute. This collection presents the latest ideas and findings on the inelastic behavior of reinforced concrete (RC) structures from the analysis and design standpoints. These papers discuss state-of-the-art concrete material models and analysis methods that can be used to simulate and understand the inelastic behavior of RC structures, as well as design issues that can improve the seismic performance of these structures. Topics include modeling of concrete behavior; modeling of RC structures (finite element approach and macro-element approach); and experimental studies, analysis, and design issues.
Modeling Of Lightly Confined Reinforced Concrete Columns Subjected To Lateral And Axial Loads
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Author : Jinsong Fan
language : en
Publisher:
Release Date : 2018
Modeling Of Lightly Confined Reinforced Concrete Columns Subjected To Lateral And Axial Loads written by Jinsong Fan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with Buildings, Reinforced concrete categories.
The collapse of most non-ductile reinforced concrete buildings is caused by the loss of column support under gravity loads when subjected to lateral seismic loads. Although some modeling approaches of reinforced concrete columns can generate a reasonably accurate prediction of flexural response, the determination of shear displacement still needs further developments. Very few models could accurately simulate the shear failure and axial collapse of non-ductile columns under seismic loading. This dissertation focuses on the development of more accurate lateral displacement models including more focus on flexure-shear interaction for total lateral deformation response of lightly confined reinforced concrete columns. Experimental studies and post-earthquake reconnaissance demonstrated that reinforced concrete columns with light or widely spaced transverse reinforcement are vulnerable to shear failure and axial failure during earthquakes. Based on experimental results, a critical crack surface is selected to analyze and predict the onset of axial failure for damaged columns. When the lateral response of the column reaches the failure limit, the shear or axial strength begins to degrade. This research proposes two simplified analytical models that incorporate the shear failure and axial load failure limit state for predicting ultimate lateral displacements. An analytical model is developed to estimate the shear strength degradation and shear displacement at shear failure. Accordingly, a modified shear response envelope of shear-critical columns is proposed to predict shear behavior after peak shear strength is reached. The proposed model for calculating ultimate shear displacement is implemented and compared to experimental data. Another analytical model is developed to predict lateral displacements at axial load failure. Shear friction mechanisms are introduced to analyze the force equilibrium condition at the onset of axial load failure along a critical crack surface of the damaged column. Parametric studies are carried out to investigate and identify the most relevant factors used in calculations. The calculated results show that the proposed models can predict the lateral load-lateral displacement relationship of the test specimens with reasonable accuracy. A modified method is presented to calculate the total lateral displacements as a combination of flexure, longitudinal bar slip, and shear components. Comparison of the calculated response and experimental data show that the axial-shear-flexure interaction approach is basically suited to predict the lateral response of RC columns dominated by shear or shear-flexure failure.
A Rational Approach Towards Modeling Of Post Peak Shear Deformation Behavior Of Reinforced Concrete Frame Elements Within Finite Element Context
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Author : Fawad Muzaffar Shaikh
language : en
Publisher:
Release Date : 2012
A Rational Approach Towards Modeling Of Post Peak Shear Deformation Behavior Of Reinforced Concrete Frame Elements Within Finite Element Context written by Fawad Muzaffar Shaikh and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
Inelastic response of reinforced concrete frame members to combined gravity and lateral loads involves the complex interaction of axial, moment and shear forces and deformations. Whereas there is a considerable body of experimental data and knowledge on the behavior of members that respond predominately in either inelastic shear or moment effects, the behavior of frame elements that are sensitive to combined shear-flexure interaction is less understood. At present, there is little agreement as to how to analyze the behavior of concrete frame elements that experience strength degradation under the combined nonlinear interaction of shear and moment. This study takes a closer look at existing analytical models that have been proposed for simulation of shear effects in frame elements. Experimental behavior of beam-columns as reported by other researchers is catalogued in order to develop an understanding of the actual physical behavior of concrete frame elements. Available experimental data of ductile and non-ductile columns is analyzed to identify key parameters which affect shear deformation behavior of beam-column elements. Bond slip penetration within the plastic hinge regions of the concrete frame elements is found to play a key role in causing shear failure and subsequent post-peak force deformation response of beam-columns. Existing concrete and steel material models are studied and an improved steel material model capable of simulating cyclic hardening, cyclic softening and mean stress relaxation is proposed. The proposed steel model is verified by comparing its simulated response with reported behavior of reinforcing bars. The suitability of the proposed steel material model to simulate random loading history is demonstrated. A numerical framework (i.e. kinematic description, solver routine and control algorithms), capable of simulating large rotation, large deformation, post-peak shear deformation behavior of frame elements is developed. A new analytical model for simulating shear deformation behavior of concrete frame elements subjected to axial, flexural and shear loading is proposed. While the modeling concepts are general, the implementation and verification of the proposed model is limited to two-dimensional response. The proposed element model is based on behavioral effects and parameters that are identified through careful analysis and interpretation of previously published tests of ductile and non-ductile beam-columns. This analytical model is then used along with the proposed numerical framework to simulate local and element level behavior of four non-ductile columns (tested by Sezen and Moehle at U.C. Berkeley), two ductile column stubs (tested by Ichinose, Imai, Okano and Ohashi at Nagoya Institute of Technology) and two beam specimens (tested by Popov, Bertero and Krawinkler at U.C. Berkeley). The proposed element formulation, along with the supporting computational framework (e.g., solution control algorithms), are shown to be capable and robust to simulate the post-peak response of beam-columns due to large flexural and shear deformations. The proposed formulation is shown to be capable of simulating the effect of cumulative flexural deformations, axial load and strength of longitudinal bars on shear strength of beam-columns. Complicated behavioral features, such as the opening of stirrups in non-ductile columns and degradation of aggregate interlock behavior with cycling, are captured in the analysis. The element model was shown to be capable of simulating the correct mode of failure observed in four tests of non-ductile columns. In addition, shear strain, stirrup strain and axial strain of beam-columns were simulated and compared with corresponding available experimental values. The values of the input parameters of the proposed element model were justified and the resulting response was compared with experimental behavior. Generally good agreement was observed between experimental and simulated values.
Hysteretic Behavior Of Reinforced Concrete Columns Subjected To High Axial And Cyclic Shear Forces
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Author : Stan W. Zagajeski
language : en
Publisher:
Release Date : 1978
Hysteretic Behavior Of Reinforced Concrete Columns Subjected To High Axial And Cyclic Shear Forces written by Stan W. Zagajeski and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1978 with Buildings categories.
Strength And Behavior Of Reinforced Concrete Slab Column Connections Subjected To Static And Dynamic Loadings
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Author : Marvin E. Criswell
language : en
Publisher:
Release Date : 1970
Strength And Behavior Of Reinforced Concrete Slab Column Connections Subjected To Static And Dynamic Loadings written by Marvin E. Criswell and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1970 with Columns, Concrete categories.
The objectives of this investigation were to study the strength and behavior of slowly (statically) loaded reinforced concrete slab-column connections and to determine the effect of rapid (dynamic) loading on the strength and behavior by comparison with the static test results. Nineteen full-scale models of a connection and adjoining slab area, consisting of a simply supported slab 84 or 94 inches square and 6-1/2 inches thick loaded concentrically on a 10- or 20-inch-square stub column at the center of the slab, were tested. The main variables were the amounts of reinforcement in the slab (p = 0.75 and 1.50 percent), the column size, and the loading speed. Eight specimens were loaded to failure statically, two were subjected to a very rapidly applied load of short duration, and nine were loaded to failure by a rapidly applied load with a rise time chosen to represent the conditions in a blast-loaded structure. The static test results are compared with 12 shear strength prediction methods. Differences between the mechanism of shear failure in slabs and beams are examined. (Author).
Nonlinear Finite Element Analysis Of Concrete Columns Subjected To Complex Loading
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Author : Adam Christopher Morgan
language : en
Publisher:
Release Date : 2018
Nonlinear Finite Element Analysis Of Concrete Columns Subjected To Complex Loading written by Adam Christopher Morgan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
"This study details the development and implementation of a finite element model within a commercial finite element code, Abaqus CAE, for the analysis of reinforced concrete (RC) bridge columns containing interlocking spirals subjected to combined loading conditions including axial, shear, bending, and torsional loads, including the post-peak response. The model is a first of its kind attempt at simulating the response of RC columns with continuous spiral transverse reinforcement and subjected to combined loading conditions including torsion. The model is utilized to determine the quasi-static load-deformation response under various proportions of the input loads and displacements. The resulting quasi-static load-deformations, i.e., 'backbone' relationships, are compared to those experimentally obtained for three 1/2-scale prototype RC bridge columns subjected to constant axial loading and slow reversed cyclic lateral loading resulting in combined flexural moment, shear, and torsional moment. It was determined that such models can simulate the behavior of such columns with a reasonable level of error for unidirectional loading, but accurate torsional response and numerical stability of such models is difficult to obtain due to convergence errors resulting from a combination of inelastic material models and multi-body constraints used to couple the motion of the column's constituent pieces together. Attempts were made to extend the finite element model to similar RC bridge columns repaired and strengthened with externally bonded fiber reinforced polymer (FRP) composite jackets, however such attempts resulted in convergence failure as the model approached inelastic behavior"--Abstract, page iii.
Shear Strength And Deformation Modeling Of Reinforced Concrete Columns
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Author : Chaitanya Patwardhan
language : en
Publisher:
Release Date : 2005
Shear Strength And Deformation Modeling Of Reinforced Concrete Columns written by Chaitanya Patwardhan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with Columns, Concrete categories.
Abstract: Effect of transverse loading, e.g., as in an earthquake, on reinforced concrete column behavior has been an attractive topic of research for the last few decades. The column behavior is typically represented by its lateral load-displacement relationship. The past research has been primarily focused on estimation of the maximum lateral load capacity rather than the load-displacement relation, which includes flexure, bond-slip, and shear deformation components. The major goal of this study is to model lateral load-shear displacement relationship. Existing models are evaluated using available experimental data. A new model is developed using one of the existing models, Modified Compression Field Theory (MCFT). The results from MCFT appear to be accurate, but the theory is very complicated to implement as it uses an iterative algorithm. Thorough investigation of MCFT analyses is performed in this study. The results show that the theory can be simplified to simple equations, which are proposed here. The proposed model is compared with the predictions obtained using existing models as well as the experimental data. The proposed model is fairly simple, and proves to be accurate.
Hysteretic Modeling Of Shear Critical Reinforced Concrete Columns
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Author : Tanmoy Chowdhury
language : en
Publisher:
Release Date : 2007
Hysteretic Modeling Of Shear Critical Reinforced Concrete Columns written by Tanmoy Chowdhury and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with Columns categories.
Abstract: Prior studies have shown that older reinforced concrete buildings designed before the introduction of the modern seismic code in the early 1970s are vulnerable to damage and collapse during an earthquake. In particular, building columns did not have the lateral strength or ductility to withstand the demands imposed by the effects of a severe earthquake ground motion, and were often the most critical components of such earthquake damage-prone structures. They were typically characterized by insufficient and poorly detailed transverse reinforcement, widely spaced stirrups and low longitudinal reinforcement ratios. The focus of this research is to develop a suitable hysteretic model that would predict the lateral deformation behavior of lightly reinforced or shear-critical columns subjected to seismic and gravity loads. Tests of reinforced concrete columns under lateral loads have shown that the total drift stems from deformations owing to flexure, reinforcement slip, and shear. The monotonic response is initially established for the separate components in order to serve as a primary backbone curve for the cyclic force-displacement relationships. Existing analytical and experimental research on lightly reinforced columns is examined. This information is used, and when required, modified to ultimately develop a suitable overall hysteretic model that would accurately predict the lateral response of this class of columns with a limited computational effort. Cyclic models are developed for each deformation component that incorporate the strength, stiffness, and energy dissipation characteristics of the structural members. The total hysteretic response was derived by coupling flexure, reinforcement slip, and shear responses as springs in series. The behavior of a column is classified into one of five categories based on a comparison of the shear, yield, and flexural strengths. The expected behavior in each category determines rules that govern the combination of the deformation components. The proposed hysteretic model is calibrated against experimental results for correlation and verification studies. Overall, the model did a reasonable job of simulating the loaddeformation relationships of shear-critical columns. It provides a suitable platform to analyze older reinforced concrete buildings with a view to determining the amount of remediation necessary for satisfactory seismic performance.
Nonlinear Time Dependent Design And Analysis Of Slender Reinforced Concrete Columns
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Author : Ka-Wai Lee
language : en
Publisher: Cuvillier Verlag
Release Date : 2004
Nonlinear Time Dependent Design And Analysis Of Slender Reinforced Concrete Columns written by Ka-Wai Lee and has been published by Cuvillier Verlag this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004 with categories.