Análisis del comportamiento de conexiones rígidas para pórticos especiales compuestos mediante modelos de elementos finitos.

Abstract

The present research focuses on the analysis of the behavior of connections for special composite frames, given the seismic hazard in Ecuador; three types of connections were studied: End Plate, External Diaphragm and Double Split Tee (DST) through finite element analysis, with square columns filled with concrete (Concrete Filled Tube, CFT). In the investigation it was necessary to apply the rotation protocols proposed by AISC (American Institute of Steel Construction) in AISC 341-16. Non-linear contact between parts that make up the connections were used, as well as the definition of the constitutive laws of each material that makes up the connection in order to capture the plastic behavior under the cyclic loads imposed in the analysis. The results were analyzed by means of three criteria: hysteretic curves, plastic deformations and stress concentration. Altogether, the DST, End Plate and external diaphragm connections agree with the experimental tests of previous investigations. The plastic deformation mechanisms were mainly located in the beam resulting in the formation of the plastic hinge. The concrete filled column remained in the linear zone without higher stress concentration while the beam only had deformation at the point of the plastic hinge. The DST connection was the one that showed the highest capacity to the rotation of 0.04 rad, considering that it exceeded with 43% of the 0.8 times the plastic moment of the beam, followed by the End plate connection with 24% and the external diaphragm connection with 8%, which is why they are qualified as rigid connections according to AISC. In this seismic Ecuadorian environment, the present research emphasizes the relevance of using numerical analysis based on standards such as AISC, to evaluate the behavior of structural connections and their capacity to resist the real conditions of the seismic conditions