PREDICTION OF CYCLIC MOMENT-ROTATION BEHAVIOUR FOR TOP AND SEAT & WEB ANGLE CONNECTIONS BY A MECHANICAL MODEL

In this paper a simple mechanical model of the joint relative moment-rotation characteristics for use in analytical modelling of MRSF systems is presented. The experimental moment-rotational behavior of full scale connections is first considered and a finite element model of the experimental set-up is developed. The inelastic moment-rotation predictions of the finite element model are compared with available experimental data. Experimental results are also compared with the mechanical model proposed by the Eurocode 3. Based on the results of this comparison a simplified mechanical model of the connection is developed. The proposed model still adopts the same "component method" approach of the Eurocode 3, but introduces a more refined criteria for the modelling of the unilateral contact between the cleat and the column flange and a different expression for the evaluation of the capacity of the joint. An extensive parametric analysis is then conducted to asses the model inelastic moment-rotation predictions and the results are compared with finite element analyses and with available experimental data. The model moment-rotation predictions are in good agreement with experimental tests and with finite element analyses. The model also gives more consistent initial stiffness and nonlinear relative moment-rotation estimates if compared to the model proposed by the Eurocode 3. The results of conducted analyses show that the model gives results which are in reasonable agreement with experimental data and are more accurate than the results of the Eurocode 3-Annex J model.