Risk Assessment of Aged Concrete Gravity Dam Subjected to Material Deterioration Under Seismic Excitation
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International Journal of Concrete Structures and Materials Open Access
RESEARCH
Risk Assessment of Aged Concrete Gravity Dam Subjected to Material Deterioration Under Seismic Excitation Tahmina Tasnim Nahar1, Anh‑Tuan Cao1 and Dookie Kim2*
Abstract This paper proposes an approach to assess and predict the seismic risk of existing concrete gravity dams (CGDs) considering the ageing effect. The combination of fragility function and cumulative absolute velocity (CAV) depend‑ ing on two failure states has been used in the analysis. It represents the time-variant degradation of the concrete structure and the conditional change of structural vulnerability in the case of the seismic excitation. Therefore, the seismic risk assessment captures here the nonlinear dynamic behavior of a concrete gravity dam through the fragility analysis. Incremental dynamic analysis for the fragility curves is adopted to state the performance of the dam in terms of different intensity measures. To assess the capacity of the aged concrete gravity dam, this research introduces a way to estimate the CAVlimit of CGDs with varying time. For a case study, an existing concrete gravity dam in Korea has been taken into consideration to apply this approach. The numerical finite element model is validated by optimizing the recorded field data. The proposed approach and its findings will be helpful to CGDs operators to ensure whether a dam needs to stop after a specific time using the extracted mathematical model. Furthermore, as this mathematical model is the function of time, the operator can get an idea about dam conditions at any specific time and can take necessary steps. Keywords: capacity evaluation, seismic behavior, time-variant degradation, tensile cracking, relative displacement, fragility function, cumulative absolute velocity, capacity model 1 Introduction The concrete gravity dams are the massive structure, and play an important role in multiple aspects, like flood control, power generation, agricultural work, water resource conservation, etc. It can create a hazardous condition to the surrounding environment and community if any failure happens after an earthquake (Hartford and Baecher 2004). For that reason, an enormous amount of research has been done until now about the structural health monitoring after an earthquake, seismic vulnerability *Correspondence: [email protected] 2 Department of Civil & Environmental Engineering, Kongju National University, 1223‑24 Cheonan‑daero, Seobuk‑gu, Cheonan, Chungcheongnam‑do 31080, Republic of Korea Full list of author information is available at the end of the article Journal information: ISSN 1976-0485 / eISSN 2234-1315
evaluation of existing dam and so on (Ansari and Agarwal 2016; Ansari et al. 2018; Fenves and Chopra 1986; Pan et al. 2009; Sen 2018; Tekie and Ellingwood 2003). The challenging issue is the ageing effect on a concrete gravity dam (CGD), where most of them are constructed for generally more than 50 years of design life (KCSC 2016) (depends on the purpose). As CGD is imp
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