Statistical analysis of the second order effects variation with the stories height of reinforced concrete buildings
Resumo In this paper the simplified method to evaluate final efforts using γz coefficient is studied considering the variation of the second order effects with the height of the buildings. With this purpose, several reinforced concrete buildings of medium height are analyzed in first and second order using ANSYS software. Initially, it was checked that the γz coefficient should be used as magnifier of first order moments to evaluate final second order moments. Therefore, the study is developed considering the relation (final second order moments/ first order moments), calculated for each story of the structures. This moments relation is called magnifier of first order moments, “γ”, and, in the ideal situation, it must coincide with the γz value. However, it is observed that the reason γ / γz varies with the height of the buildings. Furthermore, using an statistical analysis, it was checked that γ / γz relation is generally lower than 1,05 and varies significantly in accordance with the considered building and with the presence or not of symmetry in the structure.
Avaliação dos critérios para análise da estabilidade global em edifícios de concreto armado: estudo de caso. (D.O.I. 10.5216/reec.v9i2.28875)
RESUMO: A analise da estabilidade de estruturas e um procedimento de grande importância, pois ha uma grande tendencia na construcao de edificios altos e esbeltos. Neste artigo apresenta-se um estudo sobre a estabilidade global de estruturas em concreto armado, onde para a determinacao dos efeitos globais de segunda ordem, considerou-se a nao-linearidade fisica, que esta relacionada ao comportamento do material, e a nao-linearidade geometrica, que considera alteracoes na geometria da estrutura. Determinou-se dois parâmetros de estabilidade: o parâmetro ?, que define a necessidade da consideracao dos efeitos de segunda ordem e o coeficiente ?z, que alem de determinar a necessidade da consideracao dos efeitos de segunda ordem, pode ser utilizado como coeficiente amplificador dos esforcos de primeira ordem para estimar estes efeitos. No exemplo apresentado, utilizou-se o software EBERICK V. 6 da AltoQI para realizacao das analises numericas, o qual realiza a analise nao-linear geometrica por meio do processo P-Delta. Alem disso, utilizou-se o metodo analitico de porticos associados, com o auxilio do software FTOOL Versao 2008 da PUC-Rio, a fim de se fazer uma comparacao entre os resultados numericos e analiticos, e discutir a influencia dos efeitos de segunda na estabilidade global de estruturas. Os resultados apresentados reforcam a importância da utilizacao de nucleos rigidos em edificios de concreto armado quanto a analise de estabilidade global de estruturas. 
 
ABSTRACT: The analysis of stability structures is fundamental, because there is a major trend in the construction of taller and slender buildings. This paper present a study on the global stability reinforcement structures, where to for the determination of the second-order effects, was considered the material nonlinearity and geometric nonlinearity that to considered a displacement position of the structure. It was determined two parameters of stability: the ? parameter, what defines the need for consideration of second order effects and ?z coefficient, that determined the need the second order effects and can be used as an amplifier coefficient of efforts first order to estimate the second effects. In example presented, it was used the EBERICK V. 6 software (AltoQI), how complement the analysis. This program considers the geometric nonlinearity by P–Delta process, which is a method which provides more accurate results the effects of second order. Furthermore, it was used the analytical method of associated frames with the assistance FTOOL Version 2008 (PUC-Rio) software for the get of the stability parameters, in order to make a comparison between numerical and analytical results, and discuss the influence of the effects second the global stability structures. The results presented emphasize the importance of using rigid cores in reinforced concrete buildings as the global stability analysis of structures.
“To those who choose to follow in our footsteps”: making women/LGBT+ soldiers (in)visible through feminist “her-story” theater
Building on Judith Butler ’ s understanding of visibility as “ the object of continuous regulation and contestation, ” art/aesthetics studies in international relations, and feminist theater studies, we identify feminist “ her-story ” theater as a unique site where Western “ gender-/sexuality-inclusive ” soldiering is visibilized, contested, and subverted. Drawing on ethnographic observations of two award-winning dramas, interviews with artists and military hosts, and ﬁ ndings from a wider research project on contemporary British military culture, we reveal the key role of heteronormative and patriarchal cultural discourses in reproducing the ambivalent positionalities of women/LGBT+ soldiers. We argue that the very visibility of women/LGBT+ soldiers on the stage paradoxically operates to make the complexities of – and struggles against – masculinized heteronormative military cultures invisible. Furthermore, despite artists ’ attempts to dissociate empowerment through soldiering from the problematic context of modern con ﬂ icts, “ her-story ” theater ultimately entrenches gendered/racialized hierarchies that normalize Western military interventions. We conclude that only through sustained feminist re ﬂ ection on the contours of “ imagined ” futures of female/ LGBT+ soldiering can this persistently problematic (in)visibility be productively disrupted.