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Book ChapterDOI

Seismic Design Philosophy: From Force-Based to Displacement-Based Design

01 Jan 2018-pp 273-289
TL;DR: There is a need for a paradigm shift from the conventional force-based approach to the more rational displacement-based design methods to limit damages and to get uniform risk structures.
Abstract: The Indian subcontinent has experienced several earthquakes, and the major ones have caused significant damage to the buildings and lifeline structures. Researchers have realized the importance of developing a robust design method which can reduce the probability of occurrence of such damages. This paper discusses the currently followed seismic analysis techniques, their applicability and limitations, as well as the newly emerging displacement-based design methods. There is a need for a paradigm shift from the conventional force-based approach to the more rational displacement-based design methods to limit damages and to get uniform risk structures. Researchers are now focusing on the refinement of these new design methods to make them applicable to all types of buildings, bridges, and other structures.
Topics: Seismic analysis (51%), Design methods (51%)
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Journal ArticleDOI
01 Dec 2020-Vestnik MGSU
Abstract: Introduction. The standards for earthquake-resistant construction have undergone three revisions over the past decade. Each new revision was accompanied by serious discussions. However, no fundamental changes were made to the planned level of seismic safety and methods of safety assurance. Today the scientific and technical level of these standards does not satisfy many specialists, that’s why the engineering community is considering the development of new generation standards. The overall purpose of the work is to focus the attention of specialists not so much on methodological issues of design, as on unresolved or underdeveloped issues. For some of them, solutions are presented that should be considered as the subject for discussion. Materials and methods. Analyses of the regulatory requirements for the means and methods of seismic protection, publications with proposed improvements, and a comparative analysis of regulatory documents of different countries were carried out. We also analyzed the experience of implementing regulatory requirements in software systems. Results. The importance of establishing a relationship between the limit states of structures and the categories of the technical state of facilities during and after seismic impacts was emphasized. The importance of formulating requirements for the analysis of buildings and structures, different levels of responsibility when checking their response to effects of earthquakes, having different recurrence, was also emphasized. We have formulated relevant recommendations that are offered as starting points of discussions. The need for more detailed regulation of the analysis in the time domain was highlighted. Problems were identified that need to be solved both with respect to the initial seismological information and with respect to draft strain diagrams describing the construction material. Considerations were provided on the set of requirements for the design of construction facilities according to the “building + base” pattern, boundary conditions for the considered part of the base and the recalculation of accelerograms in terms of their lower boundaries. Conclusions. Although the above considerations do not claim to be the final solution to these problems, they can serve as the basis for the development of a new generation of standards or as a material, which initiates relevant research and decision making.

References
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BookDOI
13 Jan 2003-
Abstract: Minimum Design Loads for Buildings and Other Structures gives the latest consensus requirements for dead, live, soil, flood, wind, snow, rain, ice, and earthquake loads, as well as their combinatio...

3,730 citations


Book
01 Jan 2007-
Abstract: The concept of designing structures to achieve a specified performance limit state defined by strain or drift limits was first introduced, in New Zealand, in 1993. Over the following years, and in particular the past five years, an intense coordinated research effort has been underway in Europe and the USA to develop the concept to the stage where it is a viable and logical alternative to current force-based code approaches. Different structural systems including frames, cantilever and coupled walls, dual systems, bridges, wharves, timber structures and seismically isolated structures have been considered in a series of coordinated research programs. Aspects relating to characterization of seismic input for displacement-based design, and to structural representation for design verification using time-history analysis have also received special attention. This paper summarizes the general design approach, the background research, and some of the more controversial issues identified in a book, currently in press, summarizing the design procedure. perceived in terms of simple mass-proportional lateral forces, resisted by elastic structural action. In the 1940's and 50's the influence of structural period in modifying the intensity of the inertia forces started to be incorporated into structural design, but structural analysis was still based on elastic structural response. Ductility considerations were introduced in the 1960's and 70's as a consequence of the experimental and empirical evidence that well- detailed structures could survive levels of ground shaking capable of inducing inertia forces many times larger than those predicted by elastic analysis. Predicted performance came to be assessed by ultimate strength considerations, using force levels reduced from the elastic values by somewhat arbitrary force-reduction factors, that differed markedly between the design codes of different seismically-active countries. Gradually this lead to a further realization, in the 1980's and 90's that strength was important, but only in that it helped to reduce displacements or strains, which can be directly related to damage potential, and that the proper definition of structural vulnerability should hence be related to deformations, not strength. This realization has lead to the development of a large number of alternative seismic design philosophies based more on deformation capacity than strength. These are generally termed " performance-based" design philosophies. The scope of these can vary from comparatively narrow structural design approaches, intended to produce safe structures with uniform risk of damage under specified seismicity levels, to more ambitious approaches that seek to also combine financial data associated with loss-of-usage, repair, and a client-based approach (rather than a code-specified approach) to acceptable risk. This paper does not attempt to provide such ambitious guidance as implied by the latter approach. In fact, it is our view that such a broad-based probability approach is more appropriate to assessment of designed structures than to the design of new structures. The

1,249 citations


Journal ArticleDOI
Abstract: Developed herein is an improved pushover analysis procedure based on structural dynamics theory, which retains the conceptual simplicity and computational attractiveness of current procedures with invariant force distribution. In this modal pushover analysis (MPA), the seismic demand due to individual terms in the modal expansion of the effective earthquake forces is determined by a pushover analysis using the inertia force distribution for each mode. Combining these ‘modal’ demands due to the first two or three terms of the expansion provides an estimate of the total seismic demand on inelastic systems. When applied to elastic systems, the MPA procedure is shown to be equivalent to standard response spectrum analysis (RSA). When the peak inelastic response of a 9-storey steel building determined by the approximate MPA procedure is compared with rigorous non-linear response history analysis, it is demonstrated that MPA estimates the response of buildings responding well into the inelastic range to a similar degree of accuracy as RSA in estimating peak response of elastic systems. Thus, the MPA procedure is accurate enough for practical application in building evaluation and design. Copyright © 2001 John Wiley & Sons, Ltd.

1,026 citations


Journal ArticleDOI
01 May 2004-Earthquake Spectra
TL;DR: A practical and detailed example of how to perform incremental dynamic analysis (IDA), interpret the results and apply them to performance-based earthquake engineering is presented.
Abstract: We are presenting a practical and detailed example of how to perform incremental dynamic analysis (IDA), interpret the results and apply them to performance-based earthquake engineering IDA is an emerging analysis method that offers thorough seismic demand and capacity prediction capability by using a series of nonlinear dynamic analyses under a multiply scaled suite of ground motion records Realization of its opportunities requires several steps and the use of innovative techniques at each one of them Using a nine-story steel moment-resisting frame with fracturing connections as a test bed, the reader is guided through each step of IDA: (1) choosing suitable ground motion intensity measures and representative damage measures, (2) using appropriate algorithms to select the record scaling, (3) employing proper interpolation and (4) summarization techniques for multiple records to estimate the probability distribution of the structural demand given the seismic intensity, and (5) defining limit-s

408 citations


Book
21 Feb 2009-
Abstract: This multi-contributor book provides comprehensive coverage of earthquake engineering problems, an overview of traditional methods, and the scientific background on recent developments It discusses computer methods on structural analysis, provides access to the recent design methodologies, and serves as a reference for both professionals and researchers involved in earthquake engineering With an entire chapter dedicated to seismic resistant design through supplemental damping and structural control, this volume includes important advances in the characteristics of earthquake ground motions, behavior and design of structures, seismic design of non-structural systems, and more

392 citations


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