Comparative Assessments of Seismic Drift Demands and Dispersions in RC Piloti Buildings with Eccentric Cores Using CSM–MCS and IDA

Seismic drift comparisons in reinforced-concrete (RC) piloti buildings depend on core configuration, response statistic and ground-motion composition. This study compares the capacity spectrum method coupled with Monte Carlo simulation (CSM–MCS) and incremental dynamic analysis (IDA) for two nominal central-core (CC1, CC2) and two eccentric-core (EC1, EC2) configurations at intensity coordinates of 0.598 and 0.702 g. The static branch varies material strengths under fixed 5% demand damping; the dynamic branch varies motions at nominal strengths. Mean EC2-to-CC1 ratios are 6.01–6.45 for CSM–MCS and 1.39–1.55 for IDA. At 0.702 g, the IDA 95th percentile is 0.745% for CC1 and 0.630% for CC2, reversing their mean ordering. Common-record comparisons retain the baseline mean ordering, while omitting the listed Loma Prieta group reverses the two intermediate configurations. A common proportional scale leaves minimum worst-case mismatch factors of 2.93 for means and 3.95 for medians. The integrated comparison shows how response scale, distributional shape and record composition affect assessment judgments within the two conditional analysis populations.