Influência de aberturas em lajes com fôrma de aço nervurada na largura efetiva de vigas mistas biapoiadas

Abstract

Openings in the floors, in construction of multi-storey buildings, are commonly used to make passage for pipelines, cables and other components derived from the compatibility of the structural design with other areas involved (electrical, hydraulic, architectural, air conditioning, etc.). The presence of these openings in the concrete slab cause disruption in its flow stress and hence a variation in the effective width of the concrete flange significantly affecting the load capacity and flexural stiffness of the composite beam. Although the openings in slabs are usual in different types of buildings, the Brazilian standard ABNT NBR 8800: 2008 does not provide design methodology of composite beams with such openings within its effective width. Even internationally recognized standards such as the American ANSI / AISC 360-10, the Canadian CAN / CSAS16- 01 and European EN 1994-1-1: 2004, do not provide a design methodology for composite beams with these characteristics. It is therefore necessary to develop recommendations and a procedure for calculation and design that can adequately represent the behavior of such beams. This paper aims to analyze the influence of the position and dimensions of openings in composite slabs with ribbed steel deck, the effective width of composite steelconcrete beams through numerical simulation using Finite Element Method (FEM), considering non-physical linearity of the materials involved. It also has the objective to propose a procedure for the analytical calculation of the effective width of the openings in the region and its surroundings.