Details for the Design of Hybrid Nodes in Concrete Beams to Steel Beam

Details are recommended to improve the performance of beam-beam nodes formed by connecting main concrete beams with secondary steel beams, known as hybrid nodes or composite nodes in beams. The secondary steel beam node provides advantages compared to joints with inserts or anchors for the following reasons: The steel beam is continuous in the joint area which provides a more reliable performance to tearing. It increases the percentage of moment transfer by having greater rotational rigidity and decreases the positive moments in the secondary beam by continuity. Therefore, the transmission of forces from the steel beam improves the secondary beam flanges that distribute the reaction in the concrete beam and avoids the concentration of tensions. The results of laboratory experimentation under monotonic load showed that the proposed connection is acceptable, because the concrete beam exceeds the values predicted by the theory of bending and the mechanisms of collapse are described. Based on the observation and experimental tests of the form of damages caused to buildings during the 7.8 Mw earthquake of April 16, 2016 in Ecuador, details for the design of the hybrid nodes are recommended.