Improvement of Eurocode 8 Seismic Design Envelope for Bending Moments in RC Walls of High-rise Buildings

Abstract

ABSTRACT The paper focuses on the analysis of actual bending moments in RC walls of high-rise structures. A comprehensive analysis was carried out on three concrete buildings in order to evaluate the accuracy of the procedure for obtaining bending moments proposed by Eurocode 8 (EC8). The buildings are designed according to EC8 for medium ductility class (DCM) and high ductility (DCH). Nonlinear 3D models of the selected structures were subjected to 60 strong earthquake ground motions recorded on rock and stiff soil. One hundred and eighty nonlinear time-history analyses (NTHA) are carried out to compare the actual bending moments against design EC8 bending moments. Based on the findings of the conducted study, the possible improvement of EC8 bending moments design envelope for RC walls of high-rise buildings is indicated. A simple proposal for the correction of the existing EC8 bending moment envelope is introduced by its modification over the height of the wall to account bending moment increase due to the higher mode effects and by substituting EC8 design moment with wall resistance moment at the base. This improved envelope better matches the actual bending moments in RC walls of high-rise buildings. Further calibration is clearly required.