scholarly journals Shedding Light on the Effect of Uncertainties in the Seismic Fragility Analysis of Existing Concrete Dams

2020 ◽  
Vol 5 (3) ◽  
pp. 22 ◽  
Author(s):  
Giacomo Sevieri ◽  
Anna De Falco ◽  
Giovanni Marmo
Keyword(s):  
Risk Assessment ◽  
Earthquake Engineering ◽  
Seismic Risk ◽  
Numerical Models ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
Concrete Dams ◽  
Gravity Dams ◽  
Definition Of ◽  
Performance Based Earthquake Engineering

The seismic risk assessment of existing concrete gravity dams is of primary importance for our society because of the fundamental role of these infrastructures in the sustainability of a country. The seismic risk assessment of dams is a challenging task due to the lack of case histories, such as gravity dams’ seismic collapses, which hinders the definition of limit states, thus making the application of any conventional safety assessment approach difficult. Numerical models are then fundamental to predict the seismic behaviour of the complex dam-soil-reservoir interacting system, even though uncertainties strongly affect the results. These uncertainties, mainly related to mechanical parameters and variability of the seismic motion, are among the reasons that, so far, prevented the performance-based earthquake engineering approach from being applied to concrete dams. This paper discusses the main issues behind the application of the performance-based earthquake engineering to existing concrete dams, with particular emphasis on the fragility analysis. After a critical review of the most relevant studies on this topic, the analysis of an Italian concrete gravity dam is presented to show the effect of epistemic uncertainties on the calculation of seismic fragility curves. Finally, practical conclusions are derived to guide professionals to the reduction of epistemic uncertainties, and to the definition of reliable numerical models.

scholarly journals Seismic Fragility Analysis based on Artificial Ground Motions and Surrogate Modeling of Validated Structural Simulators

2020 ◽  
Author(s):  
Giuseppe Abbiati ◽  
Marco Broccardo ◽  
Imad Abdallah ◽  
Stefano Marelli ◽  
Fabrizio Paolacci
Keyword(s):  
Earthquake Engineering ◽  
Large Scale ◽  
Hazard Analysis ◽  
Computational Cost ◽  
Surrogate Modeling ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
Motion Modeling ◽  
Seismic Records ◽  
Performance Based Earthquake Engineering

This study introduces a computational framework for efficient and accurate seismic fragility analysis based on a combination of artificial ground motion modeling, polynomial-chaos-based global sensitivity analysis, and hierarchical kriging surrogate modeling. The framework follows the philosophy of the Performance-Based Earthquake Engineering PEER approach, where the fragility analysis is decoupled from hazard analysis. This study addresses three criticalities that are present in the current practice. Namely, reduced size of hazard-consistent size-specific ensembles of seismic records, validation of structural simulators against large-scale experiments, high computational cost for accurate fragility estimates. The effectiveness of the proposed framework is demonstrated for the Rio Torto Bridge, recently tested using hybrid simulation within the RETRO project.

Modeling Building Classes Using Moment Matching

2016 ◽  
Vol 32 (1) ◽  
pp. 285-301 ◽  
Author(s):  
In Ho Cho ◽  
Keith Porter
Keyword(s):  
Risk Assessment ◽  
Earthquake Engineering ◽  
Seismic Risk ◽  
Joint Distribution ◽  
Seismic Behavior ◽  
Large Scale ◽  
Earthquake Risk ◽  
Moment Matching ◽  
Performance Based Earthquake Engineering ◽  
Earthquake Risk Assessment

Large-scale earthquake risk assessment necessitates models of the seismic performance of building classes. This work addresses how to depict a class with only a few (index) buildings whose designs span the attributes that most impact the seismic behavior of the class. We propose a general numerical moment matching (MM) technique to represent those seismic attributes of index buildings, which can then be individually analyzed by second-generation performance-based earthquake engineering methods (PBEE-2). The results probabilistically combined to model the class behavior as a whole. Thereby, the model honors the joint distribution of variable features within the class and propagates all other uncertainties that PBEE-2 already recognizes. Importantly, we can reflect and propagate with rigor the uncertain attributes of buildings within a class, notably without resorting to standard distributions. The MM enables PBEE-2 to rigorously capture seismic risk assessment of a building class.

Seismic fragility analysis of concrete dams: A state-of-the-art review

2016 ◽  
Vol 128 ◽  
pp. 374-399 ◽  
Author(s):  
Mohammad Amin Hariri-Ardebili ◽  
Victor E. Saouma
Keyword(s):  
State Of The Art ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
Concrete Dams

Optical (Camera-Based) Technology for Seismic Risk Assessment

2003 ◽  
Author(s):  
Thomas Wischgoll ◽  
Tara C. Hutchinson ◽  
Falko Kuester
Keyword(s):  
Risk Assessment ◽  
Seismic Risk ◽  
New Technologies ◽  
Early Warning Systems ◽  
Field Application ◽  
Data Transport ◽  
Seismic Risk Assessment ◽  
Shake Table Tests ◽  
Global Movements ◽  
Definition Of

Due to an increasing bandwidth for data transport in recent computers, optical (camera-based) sensors with high frame rates and reasonable resolutions can nowadays be used with off-the-shelf computers. By monitoring buildings, bridges and other infrastructure with such sensors, they can greatly assist in risk assessment. In this paper, several field application examples are described, largely encompassing the areas of civil infrastructure monitoring. Optical (camera-based) systems can be particularly powerful for monitoring both local and global movements within a scene or environment. Therefore, natural hazards induced by such movements, for example during earthquake events, are an important application area for these new technologies. First, a clear definition of seismic risk assessment is provided. Subsequently, two important fields where cameras may be useful in seismic risk assessment are described. Specifically, the context of (i) early warning systems and (ii) post-earthquake assessment are addressed. An example of using the optical record from a series of large shake table tests is provided and comparison with other methods discussed.

A new approach to assessing reparability for seismic risk assessment of buildings

2020 ◽  
pp. 875529302094417
Author(s):  
Amir Safiey ◽  
Weichiang Pang
Keyword(s):  
Risk Assessment ◽  
Earthquake Engineering ◽  
Main Body ◽  
Contributing Factors ◽  
Loss Assessment ◽  
Loss Analysis ◽  
Residual Drift ◽  
Frame Building ◽  
Performance Metric ◽  
Performance Based Earthquake Engineering

Advanced performance-based earthquake engineering (PBEE), as documented by FEMA P-58 provisions, can well serve as the bedrock for a building-specific risk assessment framework. The methodology embraces three main sequential steps: collapse assessment, irreparability assessment, and component-wise loss estimation. The consequence of collapse or irreparability is typically assumed to be the total replacement value of the building. The irreparability model adopted by FEMA P-58 uses the residual drift of the building as the sole predictor. This article proposes a new irreparability prediction model tailored for the PBEE that is distinct because of two main features: (1) the monetary loss as a performance metric is chosen to inform the irreparability, enabling incorporation with the influence of different contributing factors, and (2) irreparability assessment is decoupled from the main body of the loss assessment and included as the post-loss analysis decision-making. Eventually, the proposed irreparability model called “post-loss analysis irreparability model (PLAIM)” is demonstrated through an illustrative example of a four-story wood light-frame building.

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.

Concrete constitutive models for nonlinear seismic analysis of gravity dams — state-of-the-art

1992 ◽  
Vol 19 (3) ◽  
pp. 492-509 ◽  
Author(s):  
Sudip S. Bhattacharjee ◽  
Pierre Léger
Keyword(s):  
Finite Element ◽  
Fracture Mechanics ◽  
Crack Propagation ◽  
Seismic Analysis ◽  
Numerical Models ◽  
Ground Motions ◽  
Constitutive Models ◽  
Concrete Dams ◽  
Gravity Dams ◽  
Seismic Safety

The seismic safety of concrete dams is a matter of serious concern around the world. During severe ground motions, the dams are likely to experience cracking due to low tensile resistance of concrete. Several analytical methods have been proposed in the literature for finite element crack propagation analysis of concrete structures. Due to lack of consistent results, and virtually impossible verification because of limited field experience in seismic cracking of concrete dams, the choice of a reliable constitutive model has become a complex task. A review of concrete constitutive models for nonlinear seismic analysis of gravity dams is presented herein. The relative merits of the proposed models have been critically examined. Comparing the theoretical soundness, and the advantages and inconveniences of the different analytical procedures, the nonlinear fracture mechanics model applied with a smeared crack analysis technique appears to be very promising. The present state of knowledge on material fracture parameters under transient conditions has been found to be limited. Review of the past finite element seismic fracture analyses of concrete gravity dams reveals that reliable numerical models for safety evaluation of the structures during severe ground motions have not yet been satisfactorily developed. Key words: gravity dams, constitutive models, fracture mechanics, seismic response, nonlinear analysis, finite element, crack propagation.

Sign in / Sign up

Export Citation Format

Share Document