Reliability analysis of built concrete dam

Abstract

ResumoThe conventional design of concrete gravity dams still follows the deterministic method, which does not directly quantify the effect of uncertainties on the safety of the structure. The theory of structural reliability allows the quantification of safety of these structures, from the quantification of the inherent uncertainties in resistance and loading parameters. This article illustrates application of structural reliability theory to the case study analysis of a built concrete gravity dam. Results show that reliability of the built structure is greater than that of the designed structure. The study compares reliability for design conditions, with the corresponding safety coefficients, illustrating a lack of linearity between safety coefficients and reliability. Furthermore, the study shows which are the failure modes and the design parameters with greater influence on dam safety.Keywords: structural safety assessment, concrete dams, reliability analysis.O projeto convencional de barragens de gravidade de concreto ainda segue o método determinístico, que não quantifica diretamente o efeito das incertezas na segurança da estrutura. A teoria de confiabilidade estrutural permite a quantificação da segurança destas estruturas, a partir da quantificação das incertezas inerentes aos parâmetros de resistência e solicitação. Este artigo ilustra a aplicação da confiabilidade estrutural ao estudo de caso de uma barragem de gravidade de concreto construída. Os resultados obtidos mostram que a confiabilidade da estrutura construída é maior do que da estrutura projetada. O estudo compara a confiabilidade na condição de projeto com os coeficientes de segurança resultantes, ilustrando a falta de linearidade entre coeficientes de segurança e confiabilidade. O estudo mostra ainda quais são os modos de falha e parâmetros de projeto com maior influência na segurança da estrutura.Palavras-chave: avaliação de segurança estrutural, barragens de concreto, análise de confiabilidade.

Technical and scientific aspects of dams in Brazil: a theoretical approach

“…The authors observed that structural reliability provides an objective assessment of the safety of the structure or its reliability, in addition to the probability of failure. The study corroborated previous results, illustrating the lack of proportionality between the safety factors, generally adopted in the project, and the assessed probabilities of failure (Pires et al, 2019). Hu and Ma (2018) is another important reference in this theme.…”

“…Jia and Chi (2015) is another important reference in this theme. Pires et al (2019) carried out a study of structural reliability analysis in a concrete gravity dam. The work showed the importance of quantifying uncertainty, both in the design phase and in the constructed dam.…”

Probabilistic Safety Evaluation of a Concrete arch dam Based on Finite Element Modeling and A Reliability <i>L-R</i> Approach

“…Routine risk and safety assessments of dams are carried out by using the determination approach (safety factor) [27], particularly in the static analysis of dams, in which the physical and mechanical properties of the dam body materials and the hydrostatic pressure are assumed to be constant values. The probabilistic analysis approach seeks to more accurately assess the behavior of dams and has been used in many studies [1][2][3][4][5]7,[9][10][11][12][13][14][15][16][17]26]. In such studies, the Probabilistic Design System (PDS) tool from ANSYS software is used to evaluate the probabilistic and reliability analysis of structures [4,6,20,24].…”

Reliability-based design of an earth and concrete dam.

“…[1]: The COV of γC is 4 % (JCSS, 2001) and other authors have related a COV about 3 % to 5 % (Pires et al, 2019). Nominal values were based on CFBR (CFBR, 2012) and JCSS (JCSS, 2001).…”

“…[5]: The COV of c´rc for all the different rocks varies from 36 % to 40 % (China Electric Council, 2000), 64 % to 69 % (Lo and Grass, 1994), 65 % (Fishman, 2009) and 44 % (Wilde and Johansson, 2013). Nominal values were based on Pires et al (Pires et al, 2019).…”