Computed Nonlinear Seismic Response of Reinforced-concrete Wall-frame Structures PDF Download

Author: Mehran Keshavarzian
Publisher:
ISBN:
Category :
Languages : en
Pages : 220

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Author: Mehran Keshavarzian
Publisher:
ISBN:
Category : Concrete walls
Languages : en
Pages : 246

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The paper describes dynamic tests on small shear wall structures. The purpose of the tests was to obtain information on the behavior of reinforced concrete structures loaded into their nonlinear range. The small shear wall structures were subjected to classical sine-sweep vibration tests and to generated earthquake records. The results indicate that sine-sweep tests on degrading structures do not yield useful results because of fatigue effects and because steady-state motions cannot be achieved; however, the earthquake tests did yield useful information. From the earthquake tests results, responses were obtained that were plotted on computed linear and nonlinear non-dimensionalized response spectra. For loading within the linear range, the data indicate that the equivalent viscous damping for the test structures is about 12.5%. The test results also indicate that, in general, manipulation of the viscous damping coefficient cannot be used to predict nonlinear behavior. The more significant observation was that the effective stiffness of the shear wall structures, as determined from the dynamic tests, was only about 1/5 to 1/7 of the stiffness calculated using standard calculation methods.

Author: Mehdi Saiidi
Publisher:
ISBN:
Category : Buildings
Languages : en
Pages : 214

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Author: fib Fédération internationale du béton
Publisher: fib Fédération internationale du béton
ISBN: 9782883940659
Category : Technology & Engineering
Languages : en
Pages : 206

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A brief summary of the history of seismic design as given in chapter 1, indicates that initially design was purely based on strength or force considerations. When the importance of displacement, however, became better appreciated, it was attempted to modify the existing force-based approach in order to include considerations of displacement, rather than to totally reconsider the procedure on a more rational basis. In the last decade, then, several researchers started pointing out this inconsistency, proposing displacement-based approaches for earthquake engineering evaluation and design, with the aim of providing improved reliability in the engineering process by more directly relating computed response and expected structural performance. The main objective of this report is to summarize, critically review and compare the displacement - based approaches proposed in the literature, thus favouring code implementation and practical use of rational and reliable methods. Chapter 2 Seismic performance and design objectives of this report introduces concepts of performance levels, seismic hazard representation, and the coupling of performance and hazard to define performance objectives. In fact, for displacement analysis to be relevant in the context of performance-based design, the structural engineer must select appropriate performance levels and seismic loadings. A critical review of some engineering limit states appropriate to the different performance levels is therefore proposed. In chapter 3 Conceptual basis for displacement-based earthquake resistant design, the fundamental principles associated with displacement of the ground during an earthquake and the effects, in terms of displacement, in the structure, are reviewed. The historical development guides the presentation with a review of general linear and nonlinear structural dynamics principles, general approaches to estimate displacement, for both ground and structure, and finally a general presentation of the means to measure and judge the appropriateness of the displacements of the structure in section. Chapter 4 Approaches and procedures for displacement-based design can be somehow considered the fundamental part of the report, since a critical summary of the displacement - based approaches proposed by different researchers is presented there. Displacement - based design may require specific characterization of the input ground motion, a topic addressed in Chapter 5 Seismic input. In general, various pertinent definitions of input motion for non-code format analysis are included, while peak ground parameters necessary for code base shear equations are only addressed as needed for the definition of motion for analysis. Chapter 6 Displacement capacity of members and systems addresses the fundamental problem of evaluating the inelastic displacement capacity of reinforced concrete members and realistic values of their effective cracked stiffness at yielding, including effects of shear and inclined cracking, anchorage slip, bar buckling and of load cycling. In Chapter 7 Application and evaluation of displacement-based approaches, some of the many different displacement based design procedures briefly introduced in Chapter 4 are applied to various case studies, identifying and discussing the difficulties a designer may encounter when trying to use displacement based design. Results for five different case studies designed in accordance with eight different displacement based design methods are presented. Although in general case studies are considered a useful but marginal part of a state of the art document, in this case it has to be noted that chapter 7 is possibly the most innovative and fundamental part of the whole report. The conclusions of chapter 7 are the fundamental and essential conclusions of the document and allow foreseeing a bright future for displacement - based design approaches. The state-of-art report has been elaborated over a period of 4 years by Task Group 7.2 Displacement-based design and assessment of fib Commission 7Seismic design, a truly international team of experts, representing the expertise and experience of all the important seismic regions of the world. In October 2002 the final draft of the Bulletin was presented to the public during the 1st fibCongress in Osaka. It was also there that it was approved by fib Commission 7Seismic Design.

Author: Nicholas Petalas
Publisher:
ISBN:
Category : Buildings
Languages : en
Pages : 134

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Author: P. Fajfar
Publisher: CRC Press
ISBN: 1482296667
Category : Architecture
Languages : en
Pages : 316

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Forty scientists working in 13 different countries detail in this work the most recent advances in seismic design and performance assessment of reinforced concrete buildings. It is a valuable contribution in the mitigation of natural disasters.

Author: Dietlinde Köber
Publisher: Springer Nature
ISBN: 3030335321
Category : Science
Languages : en
Pages : 440

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This book presents state-of-the-art knowledge on problems of the effects of structural irregularities on their seismic response. It also covers specific spatial and rotational seismic loads on these structures. Rapid progress in respective research on irregular structures and unconventional seismic loads requires prompt updates of the state of the art in this area. These problems are of particular interest to both researchers and practitioners because these are non-conservative effects compared with the approach of the traditional seismic design (e.g. Eurocode 8, Uniform Building Code etc.). This book will be of particular interest to researchers, PhD students and engineers dealing with design of structures under seismic excitations.

Author: Rodolfo Alvarez Sanchez
Publisher:
ISBN:
Category :
Languages : en
Pages : 228

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Reinforced concrete structural walls are frequently used as a lateral load resisting system in buildings. In some buildings affected by relatively recent seismic events, the response of the structural walls, traditionally labeled as excellent, has been somewhat unexpected and deserves attention.This dissertation focuses on enhanced numerical methodologies for the verification of the seismic response, including softening, of reinforced concrete structural wall systems. First, a Truss Model for reinforced concrete coupled structural walls is developed. Bar bond-slip, dowel action, and confining effect of the foundation are considered. Two cyclic tests, on scaled seven-story coupled walls (from literature), are used for validation. It is shown that the compressed wall piers resist most of the base shear force and that the coupling beams at lower levels develop the largest shear forces. Second, using the same benchmark test specimens, two models for the nonlinear cyclic analysis of reinforced concrete coupled walls are developed, i.e., Modified Beam-Truss Model and Enhanced Beam-Truss Model. The role of the strain penetration in diagonally reinforced coupling beams on the hysteretic energy dissipated is studied. It is verified that the computational-efficient proposed models predict well the overall response and the sliding shear failures of coupling beams. Third, the Beam-Truss Model developed in a previous study for the nonlinear cyclic analysis of reinforced concrete components is extended to compute out-of-plane buckling in structural walls. The novel Beam-Truss Model computes accurately the force-displacement responses and the buckling behavior of three test specimens reported in literature used for validation. Finally, the Beam-Truss Model is enhanced to compute the out-of-plane nonlinear shear response of wall piers in the analysis of Core-Wall-Building systems. Using the proposed model and pushover analyses, a comprehensive study on a 14-story archetype Core-Wall building is carried out. It is shown that the in-plane shear response has a large influence on the lateral strength and displacement capacity, whereas the out-of-plane shear response mainly influences the displacement capacity.

Author: Michael W. Hopper
Publisher:
ISBN:
Category :
Languages : en
Pages : 117

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This thesis aims to identify the optimal combination of hysteresis-modeling and damping parameters implemented in nonlinear dynamic analysis to obtain satisfactory correlation between calculated and measured seismic response of reinforced concrete frames. A total of five parameters are included in this investigation: initial stiffness, bond-slip rotations, post-yield stiffness, unloading stiffness, and viscous damping. These parameters directly influence the seismic response of individual frame members. In this study, frame elements are modeled using lumped plasticity by means of an elastic middle portion bounded by nonlinear springs that connect each end of the member to a rigid segment representing the beam-column joints. Three small-scale shake-table multistory test structures and two orthogonal structural systems from an existing seven-story building with recorded seismic responses are used in this study. Each test structure was analyzed using three computer programs for two separate base accelerations and the analytical responses were compared to the measured responses using the Frequency Domain Error (FDE) index. The existing building was analyzed for a single recorded seismic event. After analyzing each structure with all possible combinations of modeling parameters, the optimal combinations of parameters leading to the best correlations between the calculated and measured response were identified. Simplified rules are given to derive the modeling parameters that give consistent low values of FDE for the various structures and structural analysis programs considered.