Assessment Of Different Earthquakes Accelerometers Scaling Approaches And Their Impact On Structural Seismic Response

Accurate assessment of structural seismic response depends critically on the representation of input ground motions in nonlinear time-history analysis (NLTHA). Because recorded accelerograms rarely match target design spectra derived from codes or probabilistic seismic hazard analysis (PSHA), engineers apply scaling methods to ensure compatibility. This review synthesizes current knowledge on accelerogram scaling approaches and their impact on structural response, drawing upon an Iranian master’s thesis and recent international literature. The study identifies four main categories of scaling: time-domain amplitude scaling, frequency-domain scaling (including spectral matching), code-based procedures, and hybrid or adaptive methods. Comparative evaluations reveal that amplitude scaling, while simple, introduces systematic bias, particularly for long-period and near-fault structures. Spectral matching improves spectral compatibility but may artificially distort phase and duration. Energy-based scaling, such as Arias intensity adjustment, preserves cumulative demands and reduces dispersion in nonlinear parameters but does not always align with code-based target spectra. Code-based scaling procedures, though practical and conservative, risk inefficiency due to overdesign. The structural consequences of scaling choices are far-reaching. They affect global responses such as base shear and drift ratios, higher-mode demands such as floor accelerations, cumulative effects such as residual drift, and probabilistic assessments such as fragility curves. The thesis and broader research converge on the conclusion that no single method is universally optimal. Instead, scaling decisions must be context-dependent, tailored to structural type, hazard scenario, and performance objectives.

Keywords:

Accelerogram scaling , Nonlinear time-history analysis , Seismic response , Spectral matching , Arias intensity , Conditional mean spectrum , Near-fault ground motions