Zacarias Martin Chamberlain Pravia

Medição de caracteristicas de vibração de pontes de concreto usando telefonia móvel

Resumo This research presents an alternative way to perform a bridge inspection, which considers the dynamics parameters from the structure. It shows an experimental phase with use of a mobile phone to extract the accelerations answers from two concrete bridges, from those records is feasible to obtain natural frequencies using the Fast Fourier Transform (FFT).Numerical models with uses finite element model (FEM) allow to determine the natural frequencies from the two concrete bridges and compare with the experimental phase of each one. The final results shows it’s possible to use mobiles phones to extract vibration answers from concrete bridges and define the structural behavior of bridges from natural frequencies, this procedure could be used to evaluate bridges with lower costs.

Otimização númerica e experimental de perfis U formados a frio sujeitos à compressão

This paper presents a numeric study that aims to obtaining minimum weight of cold-formed channel columns, with and without lips. Flexural, torsional and torsional-flexural buckling of columns were considered as constraints. The design of cold-formed steel columns was prepared on the basis of the 2001 edition of the North American Specification for the Design of ColdFormed Steel Structural Members. The optimization was made through the Simulated Annealing method. Several numeric simulations are presented and discussed with the main goal of validate the proposal, as well as an experimental example that qualifies the implementation.

Simultaneous geometry and cross-section optimization of aluminum trusses

Purpose – Trusses constitute a fertile field to demonstrate the application of optimization techniques because of the possibility of several different configurations. Using such techniques allows the search for designs that minimize the use of material to safely comply with the imposed loads. Truss optimization can be classified into three categories: cross-section, shape, and topology. The purpose of this paper is to present a numerical and experimental study developed to minimize the weight of aluminum trusses, taking both the cross-sectional dimensions of the elements and the nodal coordinates as design variables. Design/methodology/approach – Initially, several numerical computer simulations were performed with an optimization program developed by combining the displacement method and a simulated annealing optimization method. Subsequently, two aluminum trusses were selected and built in order to validate the numerical results obtained. Findings – Experimental tests verified the excellent performance ...

ANÁLISE DE SEGUNDA ORDEM DE EDIFICAÇÕES INDUSTRIAIS EM TRÊS DIMENSÕES

Second order effects were historically included by the effective length method (K concept). All the studies about that methodology have been developed in frame plane, with regular rectangular frames. The new way to include those effects is the use of second order analysis, direct analysis method or alternative simplified options. This methodology was included in ANSI AISC 360 in the 13.0 version and in the 14.0 version. As before, the studies already developed for DAM analysis are in plane. In this paper, the K concept is revisited by numerical analysis, and extended to the 3D space. Using models of symmetric and non-symmetric industrial steel structures in plane, 3D stability analysis were developed, and the results were compared with plane behavior. Several conclusions and recommendations were exposed, resulting from analyzed models. Keywords: second order analysis; steel structures; irregular 3D frames. RESUMO Os efeitos de segunda ordem foram inclusos historicamente pelo metodo do comprimento efetivo de flambagem (K). Todos as pesquisas sobre analise de segunda ordem tem sido desenvolvidas no plano e com porticos regulares retangulares. As novas alternativas usam analise de segunda ordem pela analise direta e metodos simplificados. Essa metodologia foi incluida na norma Americana ANSI AISC 360 desde o ano 2005 e mantida na versao de 2010. Assim como com o conceito de comprimento efetivo, as pesquisas para analise direta de segunda ordem sao quase todas em porticos planos regulares. Neste artigo, o conceito de comprimento efetivo de flambagem e revisitado e estendido para o espaco 3D. Usando modelos nao simetricos e tridimensionais de estruturas de aco industriais, analises de estabilidade elastica e de segunda ordem em 3D foram desenvolvidos e comparados com as pesquisas e seus resultados em porticos planos. Destes estudos se obtem conclusoes fundamentais para a analise tridimensional de estruturas de aco. Palavras Chave: analise de segunda ordem; estruturas de aco; porticos tridimensionais irregulares.Second order effects were historically included by the effective length method (K concept). All the studies about that methodology have been developed in frame plane, with regular rectangular frames. The new way to include those effects is the use of second order analysis, direct analysis method or alternative simplified options. This methodology was included in ANSI AISC 360 in the 13.0 version and in the 14.0 version. As before, the studies already developed for DAM analysis are in plane. In this paper, the K concept is revisited by numerical analysis, and extended to the 3D space. Using models of symmetric and non-symmetric industrial steel structures in plane, 3D stability analysis were developed, and the results were compared with plane behavior. Several conclusions and recommendations were exposed, resulting from analyzed models.