The GCM-FE Method for the advanced analysis of steel frameworks and connections

The Generalised Component Method (GCM) has recently been formulated, incorporating the elastic and inelastic stiffnesses, the post-ultimate softening as well as the ductility of each component, thus defining a multilinear force-displacement curve for each component. By assembling the components of a connection in a model comprising multi-linear springs, as per the Component Model concept, the full-range nonlinear connection response can be obtained including the ultimate capacity, pre- and post-ultimate load-deformation responses, and the ductility before fracture and complete failure. In this paper, the GCM is implemented in an FE analysis framework of steel structural frames. The paper explains the key elements of the FE modelling, such as the integration of the connection model with adjoining members and the use of connector elements to represent components by imposing kinematic constraints and specifying nonlinear force versus displacement behaviour. The FE implementation is briefly described including the use of published Python scripts and Matlab code. The framework, termed the GCM-FE joint modelling method, is then first validated against experimental results for the bolted moment end-plate connection. Subsequently, the GCM-FE method is used to analyse a two-storey four-bay irregular steel frame and shown to provide substantially greater insight into the performance of connections than the simplified joint models used in traditional analysis methods. Specifically, the GCM-FE analysis not only provides the ultimate resistance and failure mode of the frame, considering both members and connections, but also accurately predicts the load-redistribution process inside the connections and the resultant effect on the structural framework.

Learning Objectives:
Nonlinear modelling of connection response.

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