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Dimitrios Vamvatsikos

Bio: Dimitrios Vamvatsikos is an academic researcher from National Technical University of Athens. The author has contributed to research in topics: Incremental Dynamic Analysis & Earthquake engineering. The author has an hindex of 29, co-authored 142 publications receiving 5831 citations. Previous affiliations of Dimitrios Vamvatsikos include University of Thessaly & Stanford University.


Papers
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Journal ArticleDOI
TL;DR: Incremental dynamic analysis (IDA) is a parametric analysis method that has recently emerged in several different forms to estimate more thoroughly structural performance under seismic loads as mentioned in this paper, which involves subjecting a structural model to one or more ground motion record(s), each scaled to multiple levels of intensity, thus producing one (or more) curve(s) of response parameterized versus intensity level.
Abstract: Incremental dynamic analysis (IDA) is a parametric analysis method that has recently emerged in several different forms to estimate more thoroughly structural performance under seismic loads. It involves subjecting a structural model to one (or more) ground motion record(s), each scaled to multiple levels of intensity, thus producing one (or more) curve(s) of response parameterized versus intensity level. To establish a common frame of reference, the fundamental concepts are analysed, a unified terminology is proposed, suitable algorithms are presented, and properties of the IDA curve are looked into for both single-degree-of-freedom and multi-degree-of-freedom structures. In addition, summarization techniques for multi-record IDA studies and the association of the IDA study with the conventional static pushover analysis and the yield reduction R-factor are discussed. Finally, in the framework of performance-based earthquake engineering, the assessment of demand and capacity is viewed through the lens of an IDA study. Copyright © 2001 John Wiley & Sons, Ltd.

3,334 citations

Journal ArticleDOI
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

498 citations

Journal ArticleDOI
TL;DR: In this paper, a nine-story steel moment-resisting frame is used as a testbed, employing parameterized moment-rotation relationships with non-deterministic quadrilinear backbones for the beam plastic-hinges.
Abstract: SUMMARY Incremental Dynamic Analysis (IDA) is presented as a powerful tool to evaluate the variability in the seismic demand and capacity of non-deterministic structural models, building upon existing methodologies of Monte Carlo simulation and approximate moment-estimation. A nine-story steel moment-resisting frame is used as a testbed, employing parameterized moment-rotation relationships with non-deterministic quadrilinear backbones for the beam plastic-hinges. The uncertain properties of the backbones include the yield moment, the post-yield hardening ratio, the end-of-hardening rotation, the slope of the descending branch, the residual moment capacity and the ultimate rotation reached. IDA is employed to accurately assess the seismic performance of the model for any combination of the parameters by performing multiple nonlinear timehistory analyses for a suite of ground motion records. Sensitivity analyses on both the IDA and the static pushover level reveal the yield moment and the two rotational-ductility parameters to be the most in∞uential for the frame behavior. To propagate the parametric uncertainty to the actual seismic performance we employ a) Monte Carlo simulation with latin hypercube sampling, b) point-estimate and c) flrst-order second-moment techniques, thus ofiering competing methods that represent difierent compromises between speed and accuracy. The flnal results provide flrm ground for challenging current assumptions in seismic guidelines on using a median-parameter model to estimate the median seismic performance and employing the well-known square-root-sum-of-squares rule to combine aleatory randomness and epistemic uncertainty. Copyright c ∞ 2009 John Wiley & Sons, Ltd.

277 citations

Journal ArticleDOI
TL;DR: SPO2IDA as mentioned in this paper is a software tool that is capable of recreating the seismic behavior of oscillators with complex quadrilinear backbones, which can provide a direct connection between the Static Pushover (SPO) curve and the results of Incremental Dynamic Analysis (IDA), a computer-intensive procedure that offers thorough demand and capacity prediction capability by using a series of nonlinear dynamic analyses under a suitably scaled suite of ground motion records.
Abstract: SUMMARY SPO2IDA is introduced, a software tool that is capable of recreating the seismic behavior of oscillators with complex quadrilinear backbones. It provides a direct connection between the Static Pushover (SPO) curve and the results of Incremental Dynamic Analysis (IDA), a computer-intensive procedure that offers thorough demand and capacity prediction capability by using a series of nonlinear dynamic analyses under a suitably scaled suite of ground motion records. To achieve this, the seismic behavior of numerous single-degree-of-freedom (SDOF) systems is investigated through IDA. The oscillators have a wide range of periods and feature pinching hysteresis with backbones ranging from simple bilinear to complex quadrilinear with an elastic, a hardening and a negativestiffness segment plus a final residual plateau that terminates with a drop to zero strength. An efficient method is introduced to treat the backbone shape by summarizing the analysis results into the 16%, 50% and 84% fractile IDA curves, reducing them to a few shape parameters and finding simpler backbones that reproduce the IDA curves of complex ones. Thus, vast economies are realized while important intuition is gained on the role of the backbone shape to the seismic performance. The final product is SPO2IDA, an accurate, spreadsheet-level tool for Performance-Based Earthquake Engineering that can rapidly estimate demands and limit-state capacities, strength reduction R-factors and inelastic displacement ratios for any SDOF system with such a quadrilinear SPO curve. Copyright c ∞ 2005 John Wiley & Sons, Ltd.

226 citations

Journal ArticleDOI
TL;DR: In this article, Scalar and vector Intensity Measures are developed for the efficient estimation of limit-state capacities through Incremental Dynamic Analysis (IDA) by exploiting the elastic spectral shape of individual records.
Abstract: SUMMARY Scalar and vector Intensity Measures are developed for the efficient estimation of limit-state capacities through Incremental Dynamic Analysis (IDA) by exploiting the elastic spectral shape of individual records. IDA is a powerful analysis method that involves subjecting a structural model to several ground motion records, each scaled to multiple levels of intensity (measured by the Intensity Measure or IM ), thus producing curves of structural response parameterized by the IM on top of which limit-states can be defined and corresponding capacities can be calculated. When traditional IM s are used, such as the peak ground acceleration or the first-mode spectral acceleration, the IM -values of the capacities can display large record-to-record variability, forcing the use of many records to achieve reliable results. By using single optimal spectral values as well as vectors and scalar combinations of them on three multistory buildings significant dispersion reductions are realized. Furthermore, IDA is extended to vector IM s, resulting in intricate fractile IDA surfaces. The results reveal the most influential spectral regions/periods for each limit-state and building, illustrating the evolution of such periods as the seismic intensity and the structural response increase towards global collapse. The ordinates of the elastic spectrum and the spectral shape of each individual record are found to significantly influence the seismic performance and they are shown to provide promising candidates for highly efficient IM s. Copyright c ∞ 2005 John Wiley & Sons, Ltd.

225 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, applied linear regression models are used for linear regression in the context of quality control in quality control systems, and the results show that linear regression is effective in many applications.
Abstract: (1991). Applied Linear Regression Models. Journal of Quality Technology: Vol. 23, No. 1, pp. 76-77.

1,811 citations

Journal ArticleDOI

1,604 citations

Journal ArticleDOI
TL;DR: In this paper, a formal probabilistic framework for seismic design and assessment of structures and its application to steel moment-resisting frame buildings is presented, based on realizing a performance objective expressed as the probability of exceeding a specified performance level.
Abstract: This paper presents a formal probabilistic framework for seismic design and assessment of structures and its application to steel moment-resisting frame buildings. This is the probabilistic basis for the 2000 SAC Federal Emergency Management Agency ~FEMA! steel moment frame guidelines. The framework is based on realizing a performance objective expressed as the probability of exceeding a specified performance level. Performance levels are quantified as expressions relating generic structural variables ''demand'' and ''capacity'' that are described by nonlinear, dynamic displacements of the structure. Common probabilistic analysis tools are used to convolve both the randomness and uncertainty characteristics of ground motion intensity, structural ''demand,'' and structural system ''capacity'' in order to derive an expression for the probability of achieving the specified performance level. Stemming from this probabilistic framework, a safety-checking format of the conventional ''load and resistance factor'' kind is developed with load and resistance terms being replaced by the more generic terms ''demand'' and ''capacity,'' respectively. This framework also allows for a format based on quantitative confidence statements regarding the likelihood of the performance objective being met. This format has been adopted in the SAC/FEMA guidelines.

1,580 citations

01 Jan 1990
TL;DR: The ASCE/SEI 7-05 standard as discussed by the authors provides a complete update and reorganization of the wind load provisions, expanding them from one chapter into six, and includes new ultimate event wind maps with corresponding reductions in load factors.
Abstract: Minimum Design Loads for Buildings and Other Structures provides requirements for general structural design and includes means for determining dead, live, soil, flood, wind, snow, rain, atmospheric ice, and earthquake loads, as well as their combinations, which are suitable for inclusion in building codes and other documents. This Standard, a revision of ASCE/SEI 7-05, offers a complete update and reorganization of the wind load provisions, expanding them from one chapter into six. The Standard contains new ultimate event wind maps with corresponding reductions in load factors, so that the loads are not affected, and updates the seismic loads with new risk-targeted seismic maps. The snow, live, and atmospheric icing provisions are updated as well. In addition, the Standard includes a detailed Commentary with explanatory and supplementary information designed to assist building code committees and regulatory authorities. Standard ASCE/SEI 7 is an integral part of building codes in the United States. Many of the load provisions are substantially adopted by reference in the International Building Code and the NFPA 5000 Building Construction and Safety Code. Structural engineers, architects, and those engaged in preparing and administering local building codes will find this Standard an essential reference in their practice. Note: New orders are fulfilled from the second printing, which incorporates the errata to the first printing.

974 citations