Evaluation of Seismic Performance Factors for Elevated Reinforced Concrete Tanks (original) (raw)

This paper presents a proposed methodology for reliable determination and evaluation of the seismic performance factors of elevated reinforcement concrete cylindrical tank with a frame supporting structure. The paper focuses on developing an analytical methodology using numerical modelling of representative archetype structural system. ACI 350.3-06 (Seismic Design of Liquid-Containing Concrete Structures and Commentary) [1] does not explicitly address the seismic design performance factors for this important structure. Furthermore, ASCE 7-05 (Minimum Design Loads for Buildings and Other Structures) [2] does not have an explicit provision relevance to seismic design of liquid-containing concrete structure. Therefore, the purpose of this study is to propose a reliable basis for defining/evaluating such seismic design parameters. The recommended methodology was based on the approach developed using the ATC-63 (2008); Quantification of Building Seismic Performance Factors, subsequently published as FEMA P695 (2009) [3]. The methodology referred to herein as "ATC-63" [3] represents a broad knowledge base of standard building code concepts, structural systems, relevant research and technologies utilizing state-of-theart nonlinear dynamic analysis and collapse simulation to reliably quantify system performance and response parameters for use in seismic design. In this study seismic performance factors including Qo overstrength factor, d ductility factor and R response modification factor of elevated reinforced concrete tanks were determined and evaluated by performing nonlinear static pushover analysis and nonlinear incremental dynamic time history analysis. The nonlinear dynamic time history analysis is realized by Far-Field Maximum Considered Earthquake (MCE) level ground motions consistent with ASCE 7-05 [2] provisions using three different earthquake data: El-Centro, Parkfield and Pacoima ground motion. Fluid-structure interaction is simulated using simplified analysis procedures: Housner's model. Based on the analysis results, Damage Index from the nonlinear time-history analysis is compared to that obtained by pushover analysis procedures.