Roberval José Pimenta

Estudo comparativo dos critérios de dimensionamento ao cisalhamento longitudinal em lajes mistas de aço e concreto

resumo ABNT NBR 8800 (2008) prescribes two longitudinal shear design criteria for composite slabs with ribbed decking: m-k method and partial interaction method. The m-k method is considered the worldwide standard method. In this method, the longitudinal resistant shear strength is obtained from linear regression of test results. The partial composite method is an alternative to the m-k method and shall be used only for composite slabs with a ductile behavior. In this scenario, the objective of this paper is to compare these two methods with respect to test results of full size composite slabs employing steel-deck MF 50 manufactured by METFORM. The analysis of the comparative study shows good correlation between the two methods with respect to the prediction of the ultimate strength of the tested composite slabs.

Avaliação da segurança de vigas de alma senoidal sujeitas à flambagem lateral com torção - parte 1: requisitos básicos

There are no design standards or specifications dealing with all the phenomena involved in the structural behavior of corrugated-web beams. The development of recommendations that might express their behavior more properly, within the concepts and methods of the Theory of Reliability is therefore necessary. In this research, the safety assessment of sinusoidal-web beams for the lateral-torsioned buckling failure mode is performed. To this end, in this first part, the following basic requirements are presented: (i) proposal and validation of the calculation model; (ii) statistics of basic variables. The proposed model is based on an adaptation of the standards ANSI/AISC 360-05 (2005) and ABNT NBR 8800 (2008), in which the corrugated web is neglected on the computation of geometric properties. The statistics of basic variables were obtained from literature and measurements of the actual dimensions of sinusoidal-web shapes manufactured in Brazil.

Flambagem lateral com torção em vigas com perfis de alma senoidal

A Finite Element model was developed in order to study the behavior of beams with sinusoidal webs, subjected to Lateral Torsion Buckling, taking into account residual stresses and initial imperfections. The numerical model was validated by comparison with four experimental tests. To start the analysis of the model, a linear buckling analysis is made to find the first eigenvalue and the correspondent buckling mode. The next step is to assign the buckling mode to the geometrical model and the initial imperfection to the maximum mode displacement. Then an incremental plastic analysis is done, taking into account large deflections, until the model is unable to take on any other load increments due to physical or geometrical degeneration. Comparisons between numerical and experimental results are included. Comparisons between the results of eight numerical analyses and the correspondent provisions of a procedure based on the Brazilian code NBR 8800 (1986) are also included. For these eight comparisons 6 models were chosen to reach instability in the inelastic range and 2 in the elastic range. The sinusoidal web was ignored for the calculation of the geometrical properties.

Application of general method for design of concrete columns and encased composite steel and concrete columns

Resumo The purpose of this work is the development and implementation of a numerical procedure for the design of reinforced concrete columns (RC) and composite columns with fully concrete encased steel I-section (SC). For this purpose, a computer program was developed to determine the load capacity of these columns, applying the General Method adopted by ABNT NBR 6118:2014. The program is based on an iterative process from integration of the curvatures along the column, obtained by determining the moment-curvature relationship of the cross section by the Newton-Raphson method. Several experimental and numerical results are compared to the program’s to demonstrate the accuracy of the procedure.

High Strength Steel: The Solution for the Lean Design of Industrial Buildings

This paper presents the actual case of an industrial building at CBMM’s plant in Araxá, Brazil as an example of lean design using microalloyed steels. The structure was made mostly with microalloyed ASTM A572 steel instead of the traditional carbon manganese ASTM A36 steel. This paper provides a metallurgical evaluation of the microstructures of both steel types together with their respective mechanical properties.

Avaliação da segurança de vigas de alma senoidal sujeitas à flambagem lateral com torção - Parte 2: análise de confiabilidade

There are no design standards or specifications dealing with all the phenomena involved in the structural behavior of corrugated-web beams. The development of recommendations that might express their behavior more properly, within the concepts and methods of the Theory of Reliability, is therefore necessary. In this research, the safety assessment of sinusoidal-web beams for the laterallytorsioned buckling failure mode is performed. In this second part, the reliability analysis of such elements, designed according to a procedure that incorporates the calculation model and the load and resistance factors, is performed. Herein, the following are presented: (i) the used reliability method; (ii) the performance functions; (iii) the reliability indexes implicit in the procedure. Based on the results, it is shown that the proposed procedure leads to reliable levels compared to those of plane-web shapes.