Steel–concrete composite flange plate connections — finite element modeling and parametric studies

Composite connections are defined as the regions where composite beam frames into a steel column. A composite flange plate connection with web cleats is studied here since it is expected to satisfy the seismic performance requirements at a reasonable cost. A modification of the traditional flange plate connection, termed as stiffened flange plate connection, is also studied and its merits over the flange plate connection are assessed. The flange plate and stiffened flange plate connections are analyzed by finite element method and the validity of the model developed established by comparing with the envelope of the cyclic moment–rotation curve and the failure mode obtained from tests. Parametric studies were done to understand the connection parameters influencing the moment–rotation behavior of the connections under hogging and sagging moments. Based on the results of the parametric studies, mathematical equations have been developed for predicting the initial stiffness, moment capacity and ultimate rotation under hogging and sagging moments, and thus the entire moment–rotation curve. A simplified bilinear model is also developed for use in semi-rigid frame analysis and dynamic analysis.

► A simplified finite element model is developed for composite connections.
► Flange plate and stiffened flange plate connections are analyzed using the model.
► Parametric studies are done to understand the their influence on the behavior.
► Equations have been developed for predicting the connection behavior.
► A simplified bi-linear model is also developed for use in analysis.