Estudo experimental e numérico de vigas mistas constituídas de perfil de aço tubular retangular preenchido com concreto autoadensável em escala real

Abstract

Concrete-filled steel tube structural members offer numerous advantages over reinforced concrete or steel tube elements alone. This doctoral research reports results of a study that aims to investigate the structural behavior of real scale composite beams consisting of a rectangular steel tube filled with concrete, associated or not with a concrete solid slab placed over the superior flange of the steel component. Rectangular steel tubes of 250×150×6.4 mm in dimensions and 300 MPa of yield strength were used. Self-consolidating concrete with slump flow of 660-750 mm and characteristic concrete strength of 30 MPa was used to infill the steel tubes. Concrete-filling tests were carried out on two beam specimens of 12-m in length to investigate the feasibility of casting horizontally real-scale rectangular tubes, aiming at its application at the construction site. A total of twelve 6-m long specimens were subjected to flexural test afterward, including ten CFST beams and two steel hollow section (SHS) beams for comparison. The parameters investigated were the steel-concrete interface condition, the reinforcement ratio of the concrete core and the association of a concrete solid slab placed over the rectangular steel tube. A tridimensional finite element model was developed in ABAQUS software to simulate the flexural behavior of CFST beams. The model was calibrated and validated against experimental results. The model was then used to conduct a parametric study to evaluate the influence of specific parameters on the behavior of CFST beams. The experimental and numerical results for the the beam flexural capacity and the flexural stiffness were compared with each other and with theoretically predicted values determined in accordance to either national and international standards.