Arlene Maria Sarmanho Freitas

Análise teórico-experimental de ligações parafusadas em perfis formados a frio

This paper presents a theoretical-experimental study to evaluate the behavior of bolted beam-column connections of thin-walled cold-formed steel sections. The experimental program consists of six tests with two different prototypes. The moment-rotation curves, the stiffness connection, ultimate moment and collapse modes were obtained from the tests.

Análise de ligações em perfis tubulares de aço do tipo K e KT com afastamento entre as diagonais e o montante

This work presents a study of welded gap K- and KT-joints formed by seamless steel hollow structural sections with rectangular hollow section for the chords and circular hollow section for the members. The study involves the generation, analysis and calibration of numerical models based on the finite element method, by comparison with experimental results previously obtained with full-scale prototypes. Several models were analyzed with shell elements, evaluating the radius of corner influence on the rectangular hollow section, as well as some modeling alternatives of the welds in the connections. The results of the computational analysis are in good agreement with the experimental results.

Confiabilidade de vigas metálicas dimensionadas pela norma brasileira NBR 8800.

The study of structural reliability is related to the assessment the probability of limit state violations in a structural system. Once the designer defines the relevant limits of the structural system, the safety level of these limits must be evaluated. A reliability study of hot-rolled I beams in a flexure limited state, designed in accordance with Brazilian Code NBR 8800 (1986) and draft of new NBR 8800 (2003) was done by the First Order Reliability Method (FORM). Variations of the reliability index (b) versus slenderness are plotted, and finally a methodology to obtain uniform reliability in a limited-state domain by adopting correction procedures for the strength factor is presented.

Análise teórico-experimental de ligações mistas em perfis formados a frio

This work had as a goal to determine the behavior of composite beam-column connections in cold-formed steel profiles. Experimental and theoretical studies were developed using a four-story building. The studies were based on the structural analyses and design of this construction and the experimental analyses of the projects typical joints. The experimental program had five tests in three different configurations of composite joints, which allowed setting curves for moment x rotation and rigidity.

Theoretical and experimental analysis of RHS/CHS K gap joints

This work presents a study of welded K joints with gap, formed by a structural steel hot rolled hollow section, having rectangular hollow sections at the chords and circular hollow sections in the others members. The study developed theoretical and numerical analyses for the joints, experimental tests in full scale prototypes. Theoretical analyses were performed using code standards for K joints. The results in terms of behavior, ultimate load and collapse mode were analyzed and compared with numerical (finite elements) and theoretical models. The theoretical analysis was carried out from the code regulations. The joints tested indicated the failure mode of Plastic failure of the chord face (mode A). The results showed that the loads using code regulations and the ones from the numerical analysis had good agreement for the K joint.

Estudo teórico experimental de ligações "T" e "KT", em perfis tubulares de aço

This work presents a study of welded T and KT gap joints, formed by a seamless hollow section with rectangular hollow chord sections and circular hollow sections for the members. The developed study considers theoretical and numerical analyses for the joints, experimental tests in full scale prototypes, and tests for residual stress in the rectangular hollow section. The experimental results were used in order to obtain the overall joint behavior, ultimate load, and collapse mode. The numerical analysis using finite elements methods involved the generation, testing and calibration of the experimental results. The model represents the behavior and load capacity of the tested joints. The numerical models considered or not the welding and geometric imperfections and the results were compared with the experimental data. The accomplished analyses present good correlation with the experimental results.

BEHAVIOR ANALYSIS OF BAR GAPS IN WELDED YT-JOINTS FOR ROLLED-STEEL CIRCULAR HOLLOW SECTIONS

We present a parametric analysis of gap variation between the lap brace and through brace of YT welded joints for rolled-steel circular hollow sections on plane steel structures. Our aim is to investigate the collapse behavior of YT-joints under lap brace axial compression. In particular, we focus on e/d0 ratios above 0.25 so bending moments can be taken into account during the design. We find that joint failure is primarily due to chord wall plastification (Mode A) and cross-sectional chord buckling (Mode F) in the region underneath the lap brace. Our joint design followed the Limit States Method, and our results were based on a comparative analysis of three different methods: an analytical solution derived from a set of international technical norms, an experimental analysis, and numerical modeling using Ansys as calibrated by our experimental results.

Análise teórico-experimental de elementos formados a frio perfurados submetidos à compressão

Storage rack systems are widely used in the world due their practical and economic character. They possess some structural settings, for example, the existence of perforations in the height of the columns, to fit the connections, which make more difficult the prediction of their strength. So the manufacturers associations prescribe tests to determine this resistance. This work presents the use of the finite element method to preview the resistance of the column, and alternatives to the tests are showed.

Comportamento de sistemas de armazenagem industrial do tipo Drive-in.

Steel storage rack systems are structures used to store manufacture products. These systems range from the simplest shelving structure a few meters high and hand loaded to rack clad buildings until 30 m high, served by automatic cranes. Racks are manufactured from cold-formed steel with holes in their columns. In this work is studied the Drive-in system by the commercial software ANSYS through linear and nonlinear analysis, 2D and 3D models. The specific American code to steel storage racks systems of the Rack Manufacturers Institute - RMI - was used with some modifications because this code does not enclose the Drive-in system. In this study was researched the best analysis to represent the behaviour of the Drive-in, the importance of considering the experimental results and the efficiency of using horizontal forces to represent the effect of the out-of-plumb in the structure.

Análise de fadiga de ligações tubulares soldadas de pontes treliçadas

Nesse trabalho e apresentada uma analise de fadiga de ligacoes soldadas formadas por perfis estruturais tubulares de aco sem costura. E apresentado o procedimento de estimativa de vida util a fadiga dessas ligacoes por meio dos metodos da tensao geometrica e da tensao nominal, estabelecidos no CIDECT 8 e Eurocode 3, com abordagem baseada em ciclos de tensao (curvas S-N). A filosofia de projeto associada a esta abordagem e a de vida garantida, que deve proporcionar um nivel aceitavel de confiabilidade da estrutura sem inspecoes periodicas. O modelo analisado foi o de uma ponte metalica trelicada, sendo apresentada uma discussao entre esses dois metodos abordando vantagens e limitacoes. Os resultados obtidos permitiram determinar qual metodo e melhor aplicavel para uma dada situacao de projeto