Influence of Ground Motion Scaling on the Nonlinear Seismic Response of Reinforced Concrete Buildings.

Abstract

Understanding the impact of various ground motion scaling methods on the seismic response of structures is vital for achieving accurate performance-based design. This study examines the nonlinear seismic behaviour of a G+10 reinforced concrete building subjected to five different ground motion scaling techniques: Peak Ground Acceleration (PGA) Scaling, SaT1 Scaling, Geometric Mean Scaling, One-Step Scaling, and Spectrum Matching. The structural model was developed in CSI-SAP2000 and analysed using seven pairs of actual earthquake ground motions obtained from the PEER database. The building was assumed to be located in Seismic Zone IV, resting on hard soil, and intended for commercial use. Key response parameters such as base shear, displacement, drift, and failure patterns were evaluated. Among the scaling methods, One-Step Scaling resulted in excessively high responses, frequently suggesting collapse-level drifts. PGA Scaling and Spectrum Matching, while yielding conservative values, tended to underestimate realistic structural demands. In contrast, SaT1 and Geometric Mean Scaling methods produced more stable and representative results, aligning well with the building's dynamic properties. These outcomes emphasize the critical role of selecting an appropriate ground motion scaling method in nonlinear time history analysis to ensure dependable seismic performance assessments.