Statistical Evaluation of Deflection Amplification Factors for Reinforced Concrete Structures

Keywords: Reliability Analysis, Seismic Risk Assessment, Hazard Mitigation, Structural Response, Reinforced Concrete Structures, Amplification Factors, Design Story Drifts, NEHRP Recommended Provisions, and National Earthquake Hazard Reduction Program.

Abstract: This report presents a statistical evaluation of the deflection amplification factors Cd for reinforced concrete structures. Twelve multi-degree-of-freedom structural models with various dynamic characteristics are first constructed. Next, ninety synthetic earthquakes are generated from three power spectra representing different soil conditions. Then, the non-linear and corresponding linear time history analyses are performed to produce structural response data. These data are used to derive an empirical formula for the Cd factor by the regression analysis. On the basis of this empirical formula, the Cd factors for the design of building structures are recommended. From the comparison of the proposed Cd factors with those specified in the NEHRP Recommended Provisions, it appears that most of the Cd factors specified in the NEHRP Provisions are too large and consequently, the design story drifts of structures are overestimated.