scholarly journals Modelling and Characterizing a Concrete Gravity Dam for Fragility Analysis

2019 ◽  
Vol 4 (4) ◽  
pp. 62 ◽  
Author(s):  
Segura Rocio L. ◽  
Bernier Carl ◽  
Durand Capucine ◽  
Patrick Paultre
Keyword(s):  
Earthquake Engineering ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Fragility Analysis ◽  
Past Century ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Eastern Canada ◽  
Safety Guidelines

Most gravity dams have been designed and built during the past century with methods of analysis that are now considered inadequate. In recent decades, knowledge of seismology, structural dynamics and earthquake engineering has greatly evolved, leading to the evaluation of existing dams to ensure public safety. This study proposes a methodology for the proper modelling and characterisation of the uncertainties to assess the seismic vulnerability of a dam-type structure. This study also includes all the required analyses and verifications of the numerical model prior to performing a seismic fragility analysis and generating the corresponding fragility curves. The procedure presented herein also makes it possible to account for the uncertainties associated with the modelling parameters as well as the randomness in the seismic solicitation. The methodology was applied to a case study dam in Eastern Canada, whose vulnerability was assessed against seismic events with characteristics established by the current safety guidelines.

On the Seismic Fragility Assessment of Concrete Gravity Dams in Eastern Canada

2019 ◽  
Vol 35 (1) ◽  
pp. 211-231 ◽  
Author(s):  
Rocio Segura ◽  
Carl Bernier ◽  
Ricardo Monteiro ◽  
Patrick Paultre
Keyword(s):  
Ground Motion ◽  
Fragility Curves ◽  
Limit State ◽  
Selection Method ◽  
Probabilistic Methods ◽  
Fragility Analysis ◽  
Gravity Dams ◽  
Limit States ◽  
Eastern Canada

In recent years, probabilistic methods, such as fragility analysis, have emerged as reliable tools for the seismic assessment of dam-type structures. These methods require the selection of a representative suite of ground motion records, resulting in the need for a ground motion selection method that includes all the relevant ground motion parameters in the fragility analysis of this type of structure. This article presents the development of up-to-date fragility curves for the sliding limit states of gravity dams in Eastern Canada using a record selection method based on the generalized conditional intensity measure approach. These fragility functions are then combined with the recently developed regional hazard data to evaluate the annual risk, which is measured in terms of the unconditional probability of limit state exceedance. The proposed methodology is applied to a case study dam in northeastern Canada, whose fragility is assessed through comparison with previous studies and current safety guidelines. It is observed that the more accurate procedure proposed herein produces less conservative fragility estimates for the case study dam.

Damage Index Evaluation of Concrete Gravity Dam Based on Hysteresis Behavior and Stiffness Degradation Under Cyclic Loading

2017 ◽  
Vol 17 (01) ◽  
pp. 1750009 ◽  
Author(s):  
MD. Imteyaz Ansari ◽  
Pankaj Agarwal
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Damage Index ◽  
Gravity Dam ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Cumulative Energy ◽  
Element Analysis ◽  
Hysteresis Behavior ◽  
Concrete Gravity Dams

An assessment of seismic vulnerability of concrete gravity dams based on the fragility curves needs a well-defined damage index (DI) to define different states of damage. The DI formulation for other types of structures is not applicable to concrete gravity dams due to the change in failure mechanism. In this study, a definition of DI based on the factor of safety against sliding is attempted and correlated with the DI formulation based on the natural period of the structure and the maximum crest displacement with cumulative energy dissipation. The proposed DI relies on the nonlinear behavior of the concrete gravity dam model under cyclic testing. The hysteresis behavior is also verified through the finite element analysis by considering the damaged plasticity behavior of concrete.

Geometric Configuration Effects on Nonlinear Seismic Behavior of Concrete Gravity Dam

2018 ◽  
Vol 12 (01) ◽  
pp. 1850003 ◽  
Author(s):  
Md. Imteyaz Ansari ◽  
Mohd Saqib ◽  
Pankaj Agarwal
Keyword(s):  
Nonlinear Dynamic ◽  
Seismic Behavior ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Geometric Configuration ◽  
Gravity Dam ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Concrete Gravity Dams ◽  
Dynamic Analyses

The effects of geometric configuration on the seismic vulnerability of concrete gravity dam are discussed in the present study. The seismic vulnerability of concrete gravity dams has been represented through fragility curves obtained through incremental dynamic analyses by considering their nonlinear dynamic behavior. Five different geometries of concrete gravity dams are considered and fragility analyses are carried out on the basis of Incremental Dynamic Analyses. The effect of smoothening of re-entrant corners in the geometry of high concrete gravity dam is also presented as a possible solution.

scholarly journals Seismic Fragility Analysis of Multispan Reinforced Concrete Bridges Using Mainshock-Aftershock Sequences

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Yutao Pang ◽  
Li Wu
Keyword(s):  
Reinforced Concrete ◽  
Earthquake Engineering ◽  
Design Method ◽  
Fragility Curves ◽  
Uniform Design ◽  
Time History ◽  
Fragility Analysis ◽  
Nonlinear Time History Analysis ◽  
Aftershock Sequences ◽  
System Fragility

Although the knowledge and technology of performance-based earthquake engineering have rapidly advanced in the past several decades, current seismic design codes simply ignore the effect of aftershocks on the performance of structures. Thus, the present paper investigated the effect of aftershocks on seismic responses of multispan reinforced concrete (RC) bridges using the fragility-based numerical approach. For that purpose, a continuous girder RC bridge class containing 8 bridges was selected based on the statistical analysis of the existing RC bridges in China. 75 recorded mainshock-aftershock seismic sequences from 10 well-known earthquakes were selected in this study. In order to account for the uncertainty of modeling parameters, uniform design method was applied as the sampling method for generating the samples for fragility analysis. Fragility curves were then developed using nonlinear time-history analysis in terms of the peak curvature of pier column and displacement of bearings. Finally, the system fragility curves were derived by implementing Monte Carlo simulation on multinormal distribution of two components. From the results of this investigation, it was found that, for the RC continuous bridges, the influence of aftershocks can be harmful to both bridge components and system, which increases both the component fragility of the displacement of bearings and seismic curvature of pier sections and system fragility.

scholarly journals Reliability analysis of built concrete dam

2019 ◽  
Vol 12 (3) ◽  
pp. 551-579
Author(s):  
K. O. PIRES ◽  
A. T. BECK ◽  
T. N. BITTENCOURT ◽  
M. M. FUTAI
Keyword(s):  
Structural Reliability ◽  
Failure Modes ◽  
Design Parameters ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Deterministic Method ◽  
Concrete Dam ◽  
Case Study Analysis ◽  
Concrete Gravity Dams

Abstract The 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.

scholarly journals Seismic vulnerability of traditional masonry building a case study of Byasi, Bhaktapur

2017 ◽  
Vol 4 ◽  
pp. 24-30
Author(s):  
Shyam Sundar Basukala ◽  
Prem Nath Maskey
Keyword(s):  
Seismic Vulnerability ◽  
Linear Time ◽  
Fragility Curves ◽  
Time History ◽  
Masonry Building ◽  
Masonry Buildings ◽  
Masonry Structures ◽  
Rapid Visual Screening ◽  
Visual Screening

Historic buildings of Nepal are mainly constructed from masonry structure. Since masonry structures are weak in tension which leads to the failure of structure. So, to avoid possible damage in environment lives and property it is urgent to conduct vulnerability assessments. Seismic vulnerability of historic masonry buildings constructed in Bhaktapur at Byasi area is carried out for the case study. Five load bearing masonry buildings were selected out of 147 buildings considering opening percentage, storey and type of floor for modeling in SAP 2000 V10 Various methods of rapid visual screening (FEMA 154, EMS 98) are used to determine the vulnerability of the selected building. The Selected Building response is carried out by linear time history analysis. The seismic vulnerability of masonry structures is determined in terms of fragility curves which represent the probability of failure or damage due to various levels of strong ground motions for different damage state slight, moderate, extensive and collapse. From the result of Rapid Visual Screening (RVS) and Fragility curves of the buildings it is found that whole, buildings are found vulnerable from future earthquake.

Fragility Analysis of 3D Reinforced Concrete Frames Based on Endurance Time Method with Derived Standard Deviation

2017 ◽  
Vol 11 (04) ◽  
pp. 1750011 ◽  
Author(s):  
H. A. Tavazo ◽  
A. Ranjbaran
Keyword(s):  
Standard Deviation ◽  
Seismic Vulnerability ◽  
Seismic Analysis ◽  
Fragility Curves ◽  
Computational Cost ◽  
Fragility Analysis ◽  
Easy Access ◽  
Statistical Parameters ◽  
Endurance Time ◽  
Fragility Function

Fragility curves have been developed for seismic vulnerability analysis of structures and can be generated in empirical and analytical forms. To develop analytical fragility curve, the incremental dynamic analysis (IDA) method is considered as an applicable tool for seismic analysis; however, in the cases with high modeling complexity, the computational cost of the IDA method may be very high. Therefore, an alternative method called as endurance time (ET) method can be effectively used for fragility analysis. In this study, a new, accurate and cost effective method has been introduced in order to develop analytical fragility curves based on the ET method. The results reveal that ET-based fragility curves generally agree well with IDA-based fragility curves. In addition, it is revealed that a highly matched fragility function can be fitted on fragility points using ET-based fragility analysis (due to continuity of these points in every 0.01 of IM changes). It is concluded that ET analysis offers convenient and easy access to median and logarithmic standard deviation of IMs and thus fragility function can be produced easily based on these statistical parameters. Furthermore, a new ET-based methodology is presented to consider the previously experienced earthquakes (PEEQs) in generating fragility surfaces.

Using the Conditional Spectrum Method for Improved Fragility Assessment of Concrete Gravity Dams in Eastern Canada

2016 ◽  
Vol 32 (3) ◽  
pp. 1449-1468 ◽  
Author(s):  
Carl Bernier ◽  
Ricardo Monteiro ◽  
Patrick Paultre
Keyword(s):  
Fragility Curves ◽  
Ground Motions ◽  
Accurate Estimation ◽  
Gravity Dams ◽  
Eastern Canada ◽  
Proper Selection ◽  
Concrete Gravity Dams ◽  
Target Spectrum ◽  
Ground Motion Records ◽  
Selection Of

The accurate estimation of fragility functions requires the proper selection of ground motion records at different intensity levels. However, most of the available fragility assessments of concrete dams use the same records at all intensity levels and often selects them with an inadequate target spectrum. In order to improve the fragility assessment of such structures, this paper proposes the use of records selected with the Conditional Spectrum (CS) method within a multiple stripes analysis. The approach is applied to a dam in Eastern Canada, and a comparison with the methodology used by other studies is done. It is shown that the approach proposed herein allows for the reduction of the seismic response and fragility of the dam. Moreover, the uncertainty related to material properties becomes less significant when using the CS method, and the fragility curves could be reasonably estimated by considering the ground motions as the only source of uncertainty.

Fragility analysis of a subway station structure by incremental dynamic analysis

2016 ◽  
Vol 20 (7) ◽  
pp. 1111-1124 ◽  
Author(s):  
Tong Liu ◽  
Zhiyi Chen ◽  
Yong Yuan ◽  
Xiaoyun Shao
Keyword(s):  
Dynamic Analysis ◽  
Earthquake Engineering ◽  
Seismic Vulnerability ◽  
Probabilistic Method ◽  
Incremental Dynamic Analysis ◽  
Seismic Intensity ◽  
Fragility Analysis ◽  
Subway Station ◽  
Limit States ◽  
Station Structure

Fragility analysis constitutes the basis in seismic risk assessment and performance-based earthquake engineering during which the probability of a structure response exceeding a certain limit state at a given seismic intensity is sought to relate seismic intensity and structural vulnerability. In this article, the seismic vulnerability assessment of a subway station structure is investigated using a probabilistic method. The Daikai subway station was selected as an example structure and its seismic responses are modeled according to the nonlinear incremental dynamic analysis procedure. The limit states are defined in terms of the deformation and waterproof performance of the subway station structure based on the central column drift angle and the structural tension damage distribution obtained from the incremental dynamic analysis. Fragility curves were developed at those limit states and the probability of exceedance at the limit states of operational, slight damage, life safety, and collapse prevention was determined for the two seismic hazard levels. Results reveal that the proposed fragility analysis implementation procedure to the subway station structure provides an effective and reliable seismic vulnerability analysis method, which is essential for these underground structural systems considering their high potential risk during seismic events.

scholarly journals Kriging Metamodel-Based Seismic Fragility Analysis of Single-Bent Reinforced Concrete Highway Bridges

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 238
Author(s):  
Phuong Hoa Hoang ◽  
Hoang Nam Phan ◽  
Duy Thao Nguyen ◽  
Fabrizio Paolacci
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Fragility Curves ◽  
Structural Response ◽  
Highway Bridges ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
Kriging Metamodel ◽  
Different Sources

Uncertainty quantification is an important issue in the seismic fragility analysis of bridge type structures. However, the influence of different sources of uncertainty on the seismic fragility of the system is commonly overlooked due to the costly re-evaluation of numerical model simulations. This paper aims to present a framework for the seismic fragility analysis of reinforced concrete highway bridges, where a data-driven metamodel is developed to approximate the structural response to structural and ground motion uncertainties. The proposed framework to generate fragility curves shows its efficiency while using a few finite element simulations and accounting for various modeling uncertainties influencing the bridge seismic fragility. In this respect, a class of single-bent bridges available in the literature is taken as a case study, whose three-dimensional finite element model is established by the OpenSees software framework. Twenty near-source records from different sources are selected and the Latin hypercube method is applied for generating the random samples of modeling and ground motion parameters. The Kriging metamodel is then driven on the structural response obtained from nonlinear time history analyses. Component fragility curves of the reinforced concrete pier column are derived for different damage states using the Kriging metamodel whose parameters are established considering different modeling parameters generated by Monte Carlo simulations. The results demonstrate the efficiency of the proposed framework in interpolating the structural response and deriving the fragility curve of the case study with any input conditions of the random variables.

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