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Non Linear Modeling Parameters For Reinforced Concrete Columns Subjected To Seismic Loads
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Book Synopsis Non-linear Modeling Parameters for Reinforced Concrete Columns Subjected to Seismic Loads by : Balaji Sivaramakrishnan
Download or read book Non-linear Modeling Parameters for Reinforced Concrete Columns Subjected to Seismic Loads written by Balaji Sivaramakrishnan and published by . This book was released on 2010 with total page 558 pages. Available in PDF, EPUB and Kindle. Book excerpt: The American Society of Civil Engineers (ASCE) Standard 41-06 Supplement No.1 (2007) assists engineers in modeling and evaluating the non-linear behavior of structures till collapse. Different levels of conservatism were used throughout the standard to produce modeling parameters for different structural elements, which leads to inconsistencies at the system level. Task to update current ASCE 41-06 provisions pertaining to RC structures is now handled by ACI (American Concrete Institute) committee 369 entitled "Seismic Repair and Rehabilitation". This study is a part of ACI 369 committee's effort. Existing provisions for non-linear analysis are re-assessed in this study for both rectangular and circular reinforced concrete columns. A database of 490 column tests was compiled for this project. Median rather than conservative estimates of non-linear modeling parameters were produced to achieve "best" estimates of structural behavior. Proposed modeling parameters show improved fit with experimental data over existing parameters. Data necessary for selection of acceptance criteria are provided.
Book Synopsis Non-linear Modeling Parameters for Reinforced Concrete Columns with Inadequate Lap Splices by : Wiam Al Aawar
Download or read book Non-linear Modeling Parameters for Reinforced Concrete Columns with Inadequate Lap Splices written by Wiam Al Aawar and published by . This book was released on 2015 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Structural Engineering Institute of the American Society of Civil Engineers (ASCE/SEI) publishes a Standard used across the United States and in many countries for Seismic Evaluation and Retrofit of Existing Buildings (ASCE/SEI 41-13). The Standard defines strength capacities of structural members, as well as deformation capacities through Modeling Parameters. The objective of this project was to collect and analyze needed data for updating the existing provisions in the Standard for concrete columns governed by splice failure. A database of 51 tests on columns with lap-spliced longitudinal reinforcement was assembled. Strength and deformation capacities were extracted from the test data and used to evaluate the splice failure triggers of ASCE/SEI 41-13. Deformation capacities of columns sustaining splice failures were extracted as nonlinear Modeling Parameters. The parameters were observed to increase with an increase in transverse reinforcement ratio. Additional trends between Modeling Parameters and various influential factors were also investigated and discussed.
Book Synopsis Experimental Study and Retrofit of a Non-Ductile Concrete Moment Frame Building Subjected to Biaxial Quasi-Static Seismic Loading by : Elham Moore
Download or read book Experimental Study and Retrofit of a Non-Ductile Concrete Moment Frame Building Subjected to Biaxial Quasi-Static Seismic Loading written by Elham Moore and published by . This book was released on 2021 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT OF THE DISSERTATION Experimental Study of a Non-Ductile Concrete Moment Frame Building Subjected to Biaxial Quasi-Static Seismic Loading by Elham MooreDoctor of Philosophy in Civil Engineering University of California, Los Angeles, 2021 Professor John Wright Wallace, Chair The ability of reinforced concrete (RC) columns to continue to deform with reduced capacity depends on the ability of the floor system to redistribute some of the axial load from heavily damaged element to adjacent members to prevent the collapse of the structure when that happens. Physical testing of columns, although does not fully capture the behavior of the building as a system, is the closest approach to simulate behavior of columns that undergo high constant or varying axial forces. That is by choosing boundary conditions that are representative of actual conditions, as accurately as possible. However, physical testing of a building subassembly is a more powerful tool to provide realistic information on the performance level of existing buildings under seismic loads, as well as to better demonstrate the governing failure modes of the system working together, rather than evaluating members individually. Two large-scale beam-column-slab subassemblies were tested under biaxial quasi-static, reversed cyclic loading are discussed in this report. The test specimens are replicas of elements from a non-ductile concrete moment frame building located on the UCLA campus, the Franz Tower (currently named the Pritzker Hall). The reinforced concrete building originally constructed in the late 60s consists of six levels with closely spaced perimeter columns supported on a transfer girder, with two open lower levels supported on a widely spaced column grid. The lateral force resisting system at the upper six levels consists of trapezoidal columns spaced at 4 ft. (1219 mm) on center along the perimeter of the structure, with trapezoidal beams spanning between the columns. Traditional retrofit techniques in accordance with the governing building codes and the University of California Seismic Performance Rating (UCSPC), suggested a high cost retrofit scheme with significant disruption to the architecture of the building. This is believed to be attributed to these main reasons: 1- The governing standard for seismic evaluation and rehabilitation of existing buildings, ASCE/SEI 41-13 Seismic Evaluation and Retrofit of Existing Buildings, herein referred to as ASCE 41-13, was conservative in predicting deformation capacity of building components when subjected to lateral (seismic) loading, especially when the building components fell under the non-conforming criteria, hence underestimating their performance. 2- The cross sections of the frame beams and columns were not rectangular which is the common type of cross section for typical moment frames. As a result, there was an inherent ambiguity in the capability of the non-linear modeling parameter offered by ASCE 41-13 to predict the performance achieved by the moment frames in the Franz Tower. 3- Another uncommon characteristic of this building was the aspect ratio of the moment frames (bay width/story height), which is less than 0.3 (with the beam span of 4 ft. (1219 mm) and column height of about 12. ft 9 in. (3886 mm), while aspect ratios of more than or equal to 1 are more common. Therefore, the beams were rigid and would not be able to sustain a double curvature deformation, as common in the moment frame beams. 4- The repetitive frame system around the perimeter of the building provided a high level of redundancy that was not observed in typical buildings, nor in the test data used to derive the ASCE 41-13 modeling parameters. To evaluate all the issues mentioned above, a detailed physical testing program was designed with an emphasis on obtaining the overall force-deformation backbone curve for the subassembly. In order to use the data obtained from the physical testing, it was imperative to recreate the experimental backbone curve in Perform-3D, by making necessary modifications to the modeling parameters of the building components. These modifications were based on the observed damage at each drift level, and at each building component, and included the plastic deformation capacity of the columns, flexural residual strength of the columns, and shear capacity of the beams. Those modifications were later applied to the Perform-3D model of the actual building in an attempt to assess its actual performance under seismic loading. This study presents the findings of the two biaxial tests conducted on two building subassemblies and reveals that the test specimens sustained damages beyond the Collapse Prevention and Life-Safety limits of ASCE 41-13. The specimens did not lose their gravity load-carrying capacity during the test (even after exceeding 2.5% lateral drift ratio), which also provided for a higher Expected Seismic Level Performance per UCSPR, performance rating III (seismic safety policy compliant). Finally, this study provides a holistic overview on the proposed retrofit program that includes downtime and repair costs in case of a major ground shaking, utilizing the FEMA P-58, Seismic Performance Assessment of Buildings, Methodology which was developed by the Applied Technology Council (ATC) and funded by FEMA. (ATC, 2020) This study includes building assessments per the Seismic Performance Prediction Program (SP3), including analyses per the governing standards, as well as analyses per the experimental test observations. Downtime and repair cost are of great importance to the public while not directly considered in ASCE 41-13 and other local building documents. Hence, the SP3 Risk Model Engine, was used to calculate the mean loss and time to regain function. Implementation of test data in the SP3 analysis input showed not only the retrofit program enhanced building performance in terms of life safety of the occupants, but it also showed lower expected loss, as well as significantly lower downtime in comparison to prescriptive retrofit methods.
Book Synopsis Nonlinear Time Dependent Design and Analysis of Slender Reinforced Concrete Columns by : Ka-Wai Lee
Download or read book Nonlinear Time Dependent Design and Analysis of Slender Reinforced Concrete Columns written by Ka-Wai Lee and published by Cuvillier Verlag. This book was released on 2004 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Seismic Design Aids for Nonlinear Analysis of Reinforced Concrete Structures by : Srinivasan Chandrasekaran
Download or read book Seismic Design Aids for Nonlinear Analysis of Reinforced Concrete Structures written by Srinivasan Chandrasekaran and published by CRC Press. This book was released on 2016-04-19 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tools to Safeguard New Buildings and Assess Existing OnesNonlinear analysis methods such as static pushover are globally considered a reliable tool for seismic and structural assessment. But the accuracy of seismic capacity estimates-which can prevent catastrophic loss of life and astronomical damage repair costs-depends on the use of the correct b
Book Synopsis Modeling the Post Shear Failure Behavior of Reinforced Concrete Columns by : Matthew Ronald LeBorgne
Download or read book Modeling the Post Shear Failure Behavior of Reinforced Concrete Columns written by Matthew Ronald LeBorgne and published by . This book was released on 2012 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Uniaxial Material Model Incorporating Buckling for Reinforcing Bars in Concrete Structures Subjected to Seismic Loads by : Zhiyu Zong
Download or read book Uniaxial Material Model Incorporating Buckling for Reinforcing Bars in Concrete Structures Subjected to Seismic Loads written by Zhiyu Zong and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: For reinforced concrete (RC) structures subjected to seismic loads, buckling of longitudinal reinforcing bar is a significant damage stage. The objective of this research is to identify the critical parameters that control the buckling of reinforcing bars in typical circular and rectangular RC columns subjected to cyclic lateral loads. A series of nonlinear finite element simulations of laterally loaded RC columns are carried out to simulate reinforcing bar buckling behavior. Next, to achieve computational efficiency and enable a large range of simulations for a parametric study, a simplified "bar-with-springs" model is developed wherein the longitudinal reinforcing bar in a column is isolated and simulated as a flexural member. The combined restraining mechanism affected by transverse reinforcing and column size is represented by springs at the location of each transverse bar. The simplified model is validated through comparison of average stress-strain curves of "bar-with-springs" models with corresponding "full column" models. After the validation of proposed models, which are capable of providing with "average stress-strain" response of longitudinal bars, an equivalent material model is developed for reinforcing steel in RC columns that implicitly incorporates the degrading effects of bar buckling. A comprehensive parametric study is performed to identify the effects of several important column parameters on the buckling behavior of the longitudinal reinforcement in RC columns. Features of average stress-strain curves of compressively loaded reinforcing bars are summarized. Constitutive relations as functions of critical column parameters are developed for the direct use in nonlinear structural analysis of RC structures. Comparison of the numerically simulated global response of experimentally tested RC columns confirm the value and significance of the proposed equivalent material models as a simple and effective way to include bar buckling effects in finite element analysis of RC structures.
Book Synopsis Advanced Methods for Seismic Performance Evaluation of Building Structures by : Sang Whan Han
Download or read book Advanced Methods for Seismic Performance Evaluation of Building Structures written by Sang Whan Han and published by MDPI. This book was released on 2021-01-21 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Special Issue was created to collect the most recent and novel research on seismic performance evaluation of building structures. This issue includes three important topics on seismic engineering for building structures: (1) seismic design and performance evaluation, (2) structural dynamics, and (3) seismic hazard and risk analysis. To protect building structures from earthquakes, it is necessary to conduct seismic performance evaluations on structures with reliable methods and to retrofit these structures appropriately using the results of the seismic performance evaluation.
Book Synopsis Computational Analysis of Randomness in Structural Mechanics by : Christian Bucher
Download or read book Computational Analysis of Randomness in Structural Mechanics written by Christian Bucher and published by CRC Press. This book was released on 2009-03-30 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proper treatment of structural behavior under severe loading - such as the performance of a high-rise building during an earthquake - relies heavily on the use of probability-based analysis and decision-making tools. Proper application of these tools is significantly enhanced by a thorough understanding of the underlying theoretical and computation
Book Synopsis Performance-Based Seismic Engineering: Vision for an Earthquake Resilient Society by : Matej Fischinger
Download or read book Performance-Based Seismic Engineering: Vision for an Earthquake Resilient Society written by Matej Fischinger and published by Springer. This book was released on 2014-07-15 with total page 503 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Bled workshops have traditionally produced reference documents providing visions for the future development of earthquake engineering as foreseen by leading researchers in the field. The participants of the 2011 workshop built on the tradition of these events initiated by Professors Fajfar and Krawinkler to honor their important research contributions and have now produced a book providing answers to crucial questions in today’s earthquake engineering: “What visible changes in the design practice have been brought about by performance-based seismic engineering? What are the critical needs for future advances? What actions should be taken to respond to those needs?” The key answer is that research interests should go beyond the narrow technical aspects and that the seismic resilience of society as a whole should become an essential part of the planning and design process. The book aims to provide essential guidelines for researchers, professionals and students in the field of earthquake engineering. It will also be of particular interest for all those working at insurance companies, governmental, civil protection and emergency management agencies that are responsible for assessing and planning community resilience. The introductory chapter of the book is based on the keynote presentation given at the workshop by the late Professor Helmut Krawinkler. As such, the book includes Helmut’s last and priceless address to the engineering community, together with his vision and advice for the future development of performance-based design, earthquake engineering and seismic risk management.
Book Synopsis Towards Understanding the Seismic Behaviour of GFRP Confined Concrete Columns by : Zahra Kharal
Download or read book Towards Understanding the Seismic Behaviour of GFRP Confined Concrete Columns written by Zahra Kharal and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conventional steel reinforced concrete (RC) structures are prone to corrosion, resulting in billions of dollars in damages globally annually. The use of glass-fibre reinforced polymer (GFRP) bars as internal reinforcement is a pre-emptive measure, which offers a feasible and cost-effective solution to building lasting sustainable infrastructure. Despite the many advantages of GFRP, design codes do not recommend its usage in columns primarily due to the lack of test data, especially under seismic loading. This study was undertaken to understand the seismic behaviour of concrete columns confined by GFRP transverse reinforcement. In the experimental program of this study, sixteen square columns with 305x305 mm cross-section and 1470 mm length were constructed and tested under simulated earthquake loading. Fourteen columns were reinforced with GFRP ties and steel longitudinal bars, while two columns contained GFRP ties and GFRP longitudinal bars. The results, in the form of shear vs. tip deflection and moment vs. curvature hysteresis, showed that GFRP ties can significantly enhance the seismic performance of RC columns. Test results also revealed that if appropriate confinement is provided, columns confined by GFRP ties have flexural strength, energy dissipation capacity, ductility and deformability level comparable to steel-RC columns and thus can be used effectively as primary lateral reinforcement. In the analytical phase of the study, an extensive database of FRP confined columns tested under concentric axial compression was compiled. The applicability of various existing confinement models towards the test data was investigated in detail. A new constitutive stress-strain relationship for FRP confined columns was proposed which captured the behaviour considerably better than the available models. A computation program was developed, utilizing the proposed confinement model, to conduct nonlinear analysis of GFRP confined columns subjected to simulated seismic loading. The program predicted the shear vs. tip deflection and moment vs. curvature envelope curves, and the ductility parameters with reasonable accuracy. Lastly, a critical evaluation of seismic design provisions for FRP confinement in CSA-S806 (2012) was carried out. The code provisions were found to be ambiguous and lacking in several aspects. Based on the available test results, modifications to the current code were suggested.
Book Synopsis Modeling of Lightly Confined Reinforced Concrete Columns Subjected to Lateral and Axial Loads by : Jinsong Fan
Download or read book Modeling of Lightly Confined Reinforced Concrete Columns Subjected to Lateral and Axial Loads written by Jinsong Fan and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Modeling of Inelastic Behavior of RC Structures Under Seismic Loads by : P. Benson Shing
Download or read book Modeling of Inelastic Behavior of RC Structures Under Seismic Loads written by P. Benson Shing and published by ASCE Publications. This book was released on 2001-01-01 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Modeling Parameters and Numerical Acceptance Criteria for Nonlinear Procedures-High Strength Reinforced Concrete Beams and Columns by : 夏馬爾
Download or read book Modeling Parameters and Numerical Acceptance Criteria for Nonlinear Procedures-High Strength Reinforced Concrete Beams and Columns written by 夏馬爾 and published by . This book was released on 2019 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Methodology to Model Local Nonlinearities in a Slender Reinforced Concrete Member Subjected to Seismic Deformations by :
Download or read book A Methodology to Model Local Nonlinearities in a Slender Reinforced Concrete Member Subjected to Seismic Deformations written by and published by . This book was released on 1991 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: A methodology is proposed for modeling local nonlinear behavior of slender reinforced concrete members. The nonlinearity is modeled by two orthogonal assemblages of nonlinear truss elements representing the nonlinear behavior of concrete and steel reinforcement. The trusses represent narrow strips of concrete to closely calculate the section neutral axis. This modeling procedure is computationally very efficient for seismic nonlinear dynamic analysis. Such a model is used to evaluate a critical column framing a door opening of a nuclear exhaust stack building subjected to seismic motions.
Book Synopsis Nonlinear Static and Dynamic Analysis of Reinforced Concrete Subassemlages by : Filip C Filippou
Download or read book Nonlinear Static and Dynamic Analysis of Reinforced Concrete Subassemlages written by Filip C Filippou and published by . This book was released on 1995 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Nonlinear Analysis of Reinforced Concrete Bridge Columns with Confinement Effect by : Seigo Nasu
Download or read book Nonlinear Analysis of Reinforced Concrete Bridge Columns with Confinement Effect written by Seigo Nasu and published by . This book was released on 1990 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
