The Experts below are selected from a list of 111 Experts worldwide ranked by ideXlab platform
Polona Weiss - One of the best experts on this subject based on the ideXlab platform.
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Displacement capacity of masonry buildings as a basis for the assessment of Behavior Factor: an experimental study
Bulletin of Earthquake Engineering, 2010Co-Authors: Miha Tomaževič, Polona WeissAbstract:The results of shaking table tests of a series of 1:5 scale masonry building models have been used for the assessment of values of structural Behavior Factor q for masonry structures, seismic force reduction Factors proposed for the calculation of design seismic loads by Eurocode 8, European standard for the design of structures for earthquake resistance. Six models have been tested, representing prototype buildings of two different structural configurations and built with two different types of masonry materials. The study indicated that the reduction of seismic forces for the design depends not only on the type of masonry construction system, but also on structural configuration and mechanical characteristics of masonry materials. It has been also shown that besides displacement and energy dissipation capacity, damage limitation requirement should be taken into account when evaluating the values of Behavior Factor. On the basis of analysis of experimental results a conclusion can be made, that the values at the upper limit of the proposed range of values of structural Behavior Factor q for unreinforced and confined masonry construction systems are adequate, if pushover methods are used and the calculated global ductility of the structure is compared with the displacement demand. In the case where elastic analysis methods are used and significant overstrength is expected, the proposed values are conservative. However, additional research and parametric studies are needed to propose the modifications.
Miha Tomaževič - One of the best experts on this subject based on the ideXlab platform.
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Displacement capacity of masonry buildings as a basis for the assessment of Behavior Factor: an experimental study
Bulletin of Earthquake Engineering, 2010Co-Authors: Miha Tomaževič, Polona WeissAbstract:The results of shaking table tests of a series of 1:5 scale masonry building models have been used for the assessment of values of structural Behavior Factor q for masonry structures, seismic force reduction Factors proposed for the calculation of design seismic loads by Eurocode 8, European standard for the design of structures for earthquake resistance. Six models have been tested, representing prototype buildings of two different structural configurations and built with two different types of masonry materials. The study indicated that the reduction of seismic forces for the design depends not only on the type of masonry construction system, but also on structural configuration and mechanical characteristics of masonry materials. It has been also shown that besides displacement and energy dissipation capacity, damage limitation requirement should be taken into account when evaluating the values of Behavior Factor. On the basis of analysis of experimental results a conclusion can be made, that the values at the upper limit of the proposed range of values of structural Behavior Factor q for unreinforced and confined masonry construction systems are adequate, if pushover methods are used and the calculated global ductility of the structure is compared with the displacement demand. In the case where elastic analysis methods are used and significant overstrength is expected, the proposed values are conservative. However, additional research and parametric studies are needed to propose the modifications.
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introducing eurocodes and the calculation of seismic resistance of the masonry constructions
Materijali i konstrukcije, 2008Co-Authors: Miha TomaževičAbstract:Paper discusses the results of a research conducted for dealing with the problems which, with the introduction of innovative masonry technologies have been posed by the new European standards for projecting masonry constructions in seismic zones. In the seismic construction design, ductility and dissipation capacity are taken into consideration together with the construction Behavior Factor q. The research on the seismic platform has shown that the value of the q Factor depends not only on the masonry system but also on the quality of the material and the construction configuration. Euro code presupposes shear force to be a reliable mechanism for calculating shear wall resistance force, and not the mechanism where collapsing of the walls is a consequence of the diagonal wall crack which appeared due to tensile strain. Wall Behavior analysis in cases of earthquakes, and the experimental research show that the assumption is wrong, so it is therefore recommended that the seismic masonry resistance still be determined according to the 1981 Yugoslav regulations.
Stephen P Becker - One of the best experts on this subject based on the ideXlab platform.
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biFactor latent structure of attention deficit hyperactivity disorder adhd oppositional defiant disorder odd symptoms and first order latent structure of sluggish cognitive tempo symptoms
Psychological Assessment, 2016Co-Authors: Soyean Lee, Leonard G Burns, Theodore P Beauchaine, Stephen P BeckerAbstract:The objective was to determine if the latent structure of attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) symptoms is best explained by a general disruptive Behavior Factor along with specific inattention (IN), hyperactivity/impulsivity (HI), and ODD Factors (a biFactor model) whereas the latent structure of sluggish cognitive tempo (SCT) symptoms is best explained by a first-order Factor independent of the biFactor model of ADHD/ODD. Parents' (n = 703) and teachers' (n = 366) ratings of SCT, ADHD-IN, ADHD-HI, and ODD symptoms on the Child and Adolescent Disruptive Behavior Inventory (CADBI) in a community sample of children (ages 5-13; 55% girls) were used to evaluate 4 models of symptom organization. Results indicated that a biFactor model of ADHD/ODD symptoms, in conjunction with a separate first-order SCT Factor, was the best model for both parent and teacher ratings. The first-order SCT Factor showed discriminant validity with the general disruptive Behavior and specific IN Factors in the biFactor model. In addition, higher scores on the SCT Factor predicted greater academic and social impairment, even after controlling for the general disruptive Behavior and 3 specific Factors. Consistent with predictions from the trait-impulsivity etiological model of externalizing liability, a single, general disruptive Behavior Factor accounted for nearly all common variance in ADHD/ODD symptoms, whereas SCT symptoms represented a Factor different from the general disruptive Behavior and specific IN Factor. These results provide additional support for distinguishing between SCT and ADHD-IN. The study also demonstrates how etiological models can be used to predict specific latent structures of symptom organization. (PsycINFO Database Record
Jeffrey D Burke - One of the best experts on this subject based on the ideXlab platform.
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external validation of a biFactor model of oppositional defiant disorder
Molecular Psychiatry, 2021Co-Authors: Irwin D Waldman, Richard Rowe, Khrista Boylan, Jeffrey D BurkeAbstract:Dimensions of irritability and defiant Behavior, though correlated within the structure of ODD, convey separable developmental risks through adolescence and adulthood. Irritability predicts depression and anxiety, whereas defiant Behavior is a precursor to antisocial outcomes. Previously we demonstrated that a biFactor model comprising irritability and defiant Behavior dimensions, in addition to a general Factor, provided the best-fitting structure of ODD symptoms in five large datasets. Herein we extend our previous work by externally validating the biFactor model of ODD using multiple regression and multivariate Behavior genetic analyses. We used parent ratings of DSM IV ODD symptoms, and symptom dimensions for ADHD (i.e., inattention and hyperactivity−impulsivity), conduct disorder (CD), depression/dysthymia, and generalized anxiety disorder (GAD) from 846 6−18-year-old twin pairs. We found that the ODD irritability Factor was associated only with depression/dysthymia and GAD and the ODD defiant Behavior Factor was associated only with inattention, hyperactivity−impulsivity, and CD, whereas the ODD general Factor was associated with all five symptom dimensions. Multivariate Behavior genetic analyses found all five symptom dimensions shared genetic influences in common with the ODD general, irritability, and defiant Behavior Factors. In contrast, the defiant Behavior Factor shared genetic influences uniquely with inattention and hyperactivity−impulsivity, whereas the irritability Factor shared genetic influences uniquely with depression/dysthymia and GAD, but not vice versa. This suggests that genes that influence irritability in early childhood also predispose to depression and anxiety in adolescence and adulthood. These multivariate genetic findings also support the external validity of the three ODD dimensions at the etiological level. Our study provides additional support for subtyping ODD based on these symptom dimensions, as in the revisions in the ICD-11, and suggests potential mechanisms underlying the development from ODD to Behavioral or affective disorders.
Ahmed Abed - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the seismic Behavior Factor of reinforced concrete frame structures based on comparative analysis between non linear static pushover and incremental dynamic analyses
Bulletin of Earthquake Engineering, 2015Co-Authors: Amar Louzai, Ahmed AbedAbstract:The seismic Behavior Factor R (noted q in the european seismic design code, the Eurocode 8) of reinforced concrete frame structures is evaluated based on comparative analysis between non-linear static pushover and non-linear incremental dynamic analyses. For this purpose, three-, six-, and nine-storey reinforced concrete frame structures, considered as low-, medium-, and high-rise frame, respectively, were designed according to reinforced concrete code BAEL 91 and Algerian seismic code RPA 99/Version 2003. Non-linear static pushover analysis using inverted triangular loading pattern and incremental dynamic analysis using a set of seven time-history earthquake records were carried out to compute the R Factor components, such as ductility and overstrength Factors, with the consideration of failure criteria at both member and structural levels. The results obtained by non-linear static pushover and incremental dynamic analyses are compared. According to the analysis results, it is observed that in the case of non-linear static pushover analysis, the value of the seismic Behavior Factor decreases as the number of stories increases, whereas in the case of non-linear incremental dynamic analysis, the trend observed is not the same: the value of the seismic Behavior Factor increases as the number of stories increases. This result shows that the value of the seismic Behavior Factor depends, among others parameters, on the height of a structure, which parameter is not taken into account by the seismic design codes. In the light of the information obtained from incremental dynamic analyses, it is observed that the value of the seismic Behavior Factor adopted by the seismic design code RPA 99/Version 2003 is overestimated, especially for low-rise frame structure. This paper also provides conclusions and the limitations of this study.