Full-range behaviour of semi-rigid steel connections

The paper summarises recent research programs undertaken at the University of Sydney on determining the full-range behaviour of steel connections including post-peak softening and fracture. The overall context of this work is to produce models based on the Component Method for the moment-rotation behaviour of joints that are sufficiently simple and accurate that they can be implemented in beamelement based finite element models of steel frames, so as to be able to predict the strength of steel frames by Geometric and Material Nonlinear Analysis with Imperfections (GMNIA), or “advanced” analysis, accounting for the nonlinear behaviour and strength of connections. The paper first summarises three series of tests conducted on bolted moment end-plate connections, top-and-seat angle connections and web angle connections. The tests were continued well into the postultimate range to capture the softening and fracture behaviour. Secondly, the paper summarises the Generalised Component Method which includes elastic, inelastic and softening springs to describe the full-range behaviour of each component and the complete joint model. Having set out the equilibrium and compatibility equations, the Method is applied to the connections used for the experimental investigation, demonstrating reasonable agreement. Conclusions are drawn about the suitability of the Generalised Component Method for predicting the full-range behaviour of bolted moment end plate connections. The suitability of the Method for use in designing steel frames by advanced analysis is also discussed.