NONLINEAR STATIC AND DYNAMIC ANALYSES - THE INFLUENCEOF MATERIAL MODELLING IN REINFORCED CONCRETE FRAMESTRUCTURES

摘要

There has been considerable research on modelling inelastic behaviour of reinforced concrete. However,nonlinear material models used for seismic response history analyses and for nonlinear static analysis(NSA) procedures tend to be simple. It can be argued that sophisticated material models for a complexmaterial like reinforced concrete are perhaps not essential for earthquake analysis in view of several otheruncertainties associated with the seismic phenomenon. This paper examines the influence of materialmodelling on RHA responses for a simple reinforced concrete frame structure. Five acceleration timehistories compatible to elastic design spectrum of Eurocode 8 are used for RHA. Two material models areconsidered: a concrete damaged plasticity model that uses the Drucker Prager criterion and in whichconcrete and reinforcement are modelled separately and a homogenized Drucker Prager model. In bothcases the influence of strain hardening and strain rate effects are considered. The results show that thedesign response from RHA analyses is significantly different for the two models. The paper then comparesthe NSA and RHA responses for the two material models for reinforced concrete. The NSA proceduresconsidered are the Displacement Coefficient Method (DCM) and the Capacity Spectrum Method (CSM).A comparison of RHA and NSA procedures shows that there can be a significant difference in localresponse even though the target deformation values at the control node match. Moreover, the differencebetween the mean peak RHA response and the pushover response is not independent of the materialmodel.