Relationship Between Global Displacement Ductility And Local Curvature Ductility Of Elements Subjected To Ground Motions

In seismic design method for structural system capacity, the collapse resistancedesign for reinforced concrete structures necessarily adopts the calculation methods tocontrol the failure modes and form the best energy-dissipating mechanism. In order toeffectively realize the controlling of the global failure modes under earthquakeactions, it is a basic issue for the seismic design to master the relationship between theductility of member of structure. The present paper reports the relationship betweenthe curvature ductility demands of column and the global displacement ductilitydemands of reinforced concrete structures under earthquake actions, the relationshipbetween the curvature ductility demands of reinforced concrete columns andshear-walls and the interstory displacement ductility demand of frame-shear wallstructure under earthquake actions. The main contents and conclusions are as follows：1. Employing a5-story and a10-story RC frame numerical structure with adesignated moment-curvature hysteretic-rule, by nonlinear dynamic time analysis andelastic-plastic static pushover analysis, the influence of earthquake peak accelerationand strong column factors on the maximum displacement ductility demands ofstructure and maximum curvature ductility demands of columns were obtained. Theresults show that the maximum displacement ductility demands of structure and themaximum curvature ductility demands of columns increase with an increase inearthquake peak acceleration and decrease with an increase in strong column factors.By using statistical fitting methods the quantitative relationship between the curvatureductility demands of RC frame column and the global structural displacementductility demands was established.2. Employing a15-story and a30-story RC frame-shear wall numerical structure.with a designated moment-curvature hysteretic-rule, by nonlinear dynamic timeanalysis and elastic-plastic static pushover analysis, the influence of earthquake peakacceleration and bending-shear ratio on the maximum displacement ductility demandof structure, the maximum curvature ductility demands of columns and shear walls areobtained. The results show that the curvature ductility demands of columns，shearwalls and the interstory displacement ductility demands increase with increase in earthquake peak acceleration; the curvature ductility demands of shear wall decreasewith increase in bending shear ratio, but the curvature ductility demands of columnsand the interstory displacement ductility demands increase with increase in bendingshear ratio. By using statistical fitting methods the relationship between the curvatureductility demands of columns and the structural interstory displacement ductilitydemand, as well as relationship between the curvature ductility of shear walls and theinterstory displacement ductility demands are established.