Effect of modelling parameters on non-linear seismic response of concrete structures

The non-linear numerical analysis of reinforced-concrete structures presents several difficulties due to the complicated behaviour of reinforced concrete under cyclic lateral loading. For practical use, design guidelines provide simplified non-linear models which are implemented in many structural analysis programs. However, restrictions and assumptions on which the models are based may influence the seismic response of existing structures. The primary aim of the work reported in this paper was to identify possible differences in structural response due to selected non-linear modelling parameters. Based on these findings, the aim was then to provide guidance for practical computer models capable of representing a realistic non-linear seismic response. A set of numerical models was constructed and then a force–deformation relationship for each model was compared with experimental results. Sensitivity of response due to changes in each member's modelled plasticity and hysteresis was further investigated on a ten-storey reinforced-concrete building under five different seismic inputs. The analyses confirmed that storey displacements and degree of plastic deformation were influenced by modelling preferences. A fibre model was found to be more reliable in reflecting non-linear behaviour.