Momento fletor resistente à flambagem lateral com distorção de vigas casteladas mistas de aço de concreto

Abstract

Castellated steel beams are structural elements with standard hexagonal web openings, manufactured from the web expansion of solid-web profiles which gives greater inertia to the cross-section, increasing the strength and bending stiffness. These beams can be simply supported, continuous and semicontinuous and can be designed as composite when there is a shear connection between the steel profile and the concrete slab. In continuous and semicontinuous composite beams, the lateral displacement and rotation of the bottom flange, through the web distortion, in the hogging moments region, where part of the steel profile is compressed, can cause a type of instability known as lateral-distortional buckling (LDB). In the present study, a new calculation procedure to determine the elastic critical moment and the resistant bending moment to lateral-distortional buckling of composite steel-concrete castellated beams was developed. For this, equations were produced to calculate the web stiffness, elastic critical moment and resistant bending moment. Approximately 20000 numerical finite element models were processed using ANSYS software and validated with experimental results from the literature and finally analyzed for the development of the proposed calculation procedure. The results obtained according to the proposed procedure for the elastic critical moment, presented a coefficient of variation of 1.4% for uniform bending moment and 2.7% for non-uniform bending moment, in relation to the numerical models. In the case of the resistant bending moment, the coefficient of variation was 5.4%. Therefore, the results using the proposed analytical procedure indicate excellent suitability with numerical results.