Title: Risk Assessment of Aged Concrete Gravity Dam Subjected to Material Deterioration Under Seismic Excitation

Author(s): Tahmina Tasnim Nahar, Anh‑Tuan Cao and Dookie Kim

Publication: IJCSM

Volume: 14

Issue:

Appears on pages(s):

Keywords: capacity evaluation, seismic behavior, time‑variant degradation, tensile cracking, relative displacement, fragility function, cumulative absolute velocity, capacity model

DOI: 10.1186/s40069-020-00430-z

Date: 11/30/2020

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.