Análise numérico-experimental de chumbador de base de pilar de aço submetido ao cisalhamento

Abstract

The column base connection is responsible for transferring the superstructure actions to the foundation and consists, typically, of a base plate and threaded steel bars or anchor rods. A grout layer is used for filling the clearance between the base plate and the top of concrete block, usually composed of a fluid-based hydraulic cementitious material with specific mechanical properties as high strength, negligible shrinkage, brittleness and delayed curing. Epoxy-based materials may be used as a more efficient material on applications with impact and dynamic loads or when a quick cure is required but as it is a recently developed material, its adoption of occurs empirically. There are few studies about the use of this material in base column connections and mainly about its contribution to shear resistance due to the higher strength of this material. The international codes of steel and composite structures do not provide design guidance for the application of this material in base connections. Because of this lack of information, this work presents an experimental campaign about the behaviour of regular column bases, with a pre-installed steel anchor rod and grout layer composed of cement and epoxy materials, subject to monotonic shear forces. Based on the results obtained in the experimental evaluations, numerical analyses were developed in parameterized finite elements, varying the main parameters that could influence the ultimate resistance of the anchors. This developed numerical database was compared with procedures proposed by other authors and led to the proposition of an analytical design procedure to determine the resistance capacity of the set of anchors of the column base connection subjected to shear force.