Nonlinear dynamic analysis of steel portal frames with semi-rigid connections

This paper presents a semi-rigid low-rise portal frame nonlinear dynamic analysis. The main objective of this investigation was to propose a modelling strategy to represent the dynamical behaviour of semi-rigid joints under dynamic actions implemented on the ANSYS finite element software. The developed finite element model included the geometrical non-linearity and considered the influence of a non-linear and hysteretic connection stiffness. The updated Lagrangean formulation was used to model the geometrical non-linearity. The results of the present investigation also indicated that when semi-rigid joints geometrical non-linearity effects are considered in the steel frames dynamical response some significant discrepancies in the frame dynamical behaviour could occur.