Dimensionamento de vigas de rolamento compostas por perfil I e cantoneiras

Abstract

With the objective of providing support and being the passage way for overhead cranes, crane runway beams are structural elements often designed as simply supported I-section beams (in rolled or welded steel), doubly symmetrical or monosymmetric. The loads transmitted by the overhead crane wheels apply both vertical and horizontal loads at the top of the rail. Due to the distance of these loads in relation to the torsion center of the cross section, flexion and torsion are simultaneously caused. However, ABNT NBR 8800: 2008 does not present methods to be used so that these particularities are considered when designing these beams. This work presents a review of the literature and the technical specifications (both Brazilian and international) most used in Brazil as a basis for the design of crane runway beams. It is proposed, to obtain more efficient cross-sectional properties, the use of crane runway beams composed of laminated I-sections with two angles welded on their upper flanges (I+2L-section). Based on the bibliography, criteria are defined for the verification of the limit states of beams with this type of cross section. Then, for different loads and spans, the design of crane runway beams with I+2L-section and in I-section is performed. The results are compared with each other in relation to the economy of self-weight, showing that the I+2L-sections are significantly lighter structural solutions.