Experimental and numerical analysis of the strain-rate effect on fully welded connections

This paper presents experimental and numerical results of dynamic cyclic tests carried out on two full-scale specimens of welded beam-to-column connections. In order to simulate the nonlinear dynamic behaviour of tested specimens, a fibre-based finite element beam is used to model beam and column members and a nonlinear rotational spring is also used to model welded connections. The effect of strain rate on beam and column behaviour is taken into account for each constitutive fibre using the Perzyna law. The effect of strain rate on welded connection is taken into account by extending the static Richard model to simulate its dynamic behaviour. The Krawinkler–Zoheri model, expressed as a function of normalized cumulative plastic strain, is introduced to quantify damage and degrading behaviour in terms of the strain-rate effect. The finite element Drain-2dx software is first upgraded for this purpose to carry out numerical investigations. The analytical results obtained from the numerical simulation, taking the strain rate effect and damage accumulation into account, predict well the structural dynamic behaviour up to failure of welded connections when compared with available experimental data.

Research highlights
► Drain-2dx software is upgraded to take into account the effect of strain rate.
► Nonlinear dynamic rotational spring is developed to model welded connections.
► Web panel dissipates through inelastic deformations more than 80% of seismic energy.
► Strain rate could reduce the number of cycles to failure by more than 30%.