scholarly journals Effective Safety Assessment of Aged Concrete Gravity Dam based on the Reliability Index in a Seismically Induced Site

2021 ◽  
Vol 11 (5) ◽  
pp. 1987
Author(s):  
Tahmina Tasnim Nahar ◽  
Md Motiur Rahman ◽  
Dookie Kim
Keyword(s):  
Risk Assessment ◽  
Reliability Index ◽  
Safety Assessment ◽  
Focal Point ◽  
Aging Effect ◽  
Element Model ◽  
Gravity Dam ◽  
Concrete Gravity Dam ◽  
Safety Level ◽  
Target Reliability Index

The seismic performance of the aged-concrete gravity dam (aged-CGD) by safety assessment based on the reliability-index is the main focal point of this study. Determination of reliability-index has been handled by the site seismic hazard analysis with the help of PSHRisk-tool (developed by the authors) and risk assessment. Incorporated with the uncertainties, the failure probability has been carried out by the IDA and fragility analysis. For the nonlinear finite element model of the CGD, the concrete damage plasticity (CDP) model is adopted. To investigate the aging effect, the hygro-chemo-mechanical model has been taken for different years consideration. Through the failure risk assessment of serviceability and safety level, the target reliability index has been determined here for an existing CGD in Korea. Despite several types of research on the CGD safety assessment, the main novelty of this proposed approach will help the dam operator to check the safety barrier for the aged-CGD. A safety index is investigated by comparing the target reliability-index of the age-CGD with the reliability-index for two potential earthquake levels. However, the proposed approach can implement to check the safety range of any seismic site for any set of earthquakes.

scholarly journals Frequency Analysis of Concrete Gravity Dam with Finite Element Model and LHS Method

2019 ◽  
Vol 3 (3) ◽  
pp. 13-19
Author(s):  
M. Pasbani Khiavi ◽  
A. Feizi ◽  
M. Jalali ◽  
◽  
◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Frequency Analysis ◽  
Element Model ◽  
Gravity Dam ◽  
Concrete Gravity Dam

A Reliability-Based Energy Approach for Design Optimization of Blast Resistant Composites

2011 ◽  
Author(s):  
Michael P. Sheyka ◽  
Jung J. Kim ◽  
Arife B. Altunc ◽  
Mahmoud M. Reda Taha
Keyword(s):  
Reliability Index ◽  
Composite Plate ◽  
Element Model ◽  
Probability Of Failure ◽  
Energy Approach ◽  
Aluminum Composite ◽  
Elastoplastic Behavior ◽  
Target Reliability Index ◽  
Composite Layers ◽  
Strong Material

In the last three decades, significant efforts have been conducted for developing blast-resistant composites. Some of these efforts were focused on enhancing the stiffness and the strength of the composite materials. Here, an energy approach aiming at maximizing energy absorption in composite layers is used. The optimization is based on combining two materials A and B. While material A is strong, material B is ductile, thus a mechanism of energy reflection and absorption is developed within the composite layers. In this study, a simplified dynamic model is first developed to simulate the elastoplastic behavior of a composite plate subject to blast load. For an uncertain blast event, the probability of failure of each layer is evaluated using Monte Carlo method. By assigning a relatively high probability of failure (low target reliability index) of the energy absorbing layer and a relatively low probability of failure (high target reliability index) to the strong layer, the thickness of the composite layers is optimized. A case study for the design of a two layer composite plate made of Aluminum and Titanium subjected to an uncertain blast event is simulated and presented. A finite element model of the optimal Titanium and Aluminum composite plate is developed using explicit blast simulation to confirm the efficiency of the proposed design approach.

scholarly journals Risk Assessment of a Battery-Powered High-Speed Ferry Using Formal Safety Assessment

Safety ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 39
Author(s):  
Haibin Wang ◽  
Evangelos Boulougouris ◽  
Gerasimos Theotokatos ◽  
Alexandros Priftis ◽  
Guangyu Shi ◽  
...  
Keyword(s):  
Risk Assessment ◽  
High Speed ◽  
Safety Assessment ◽  
Assessment Procedure ◽  
Event Tree ◽  
Maritime Industry ◽  
Event Tree Analysis ◽  
Safety Level ◽  
Tree Analysis ◽  
Formal Safety Assessment

Fully electric ships have been widely developed, investigated and evaluated by the maritime industry as a potential solution to respond to the emissions control required according to the International Maritime Organization (IMO). This study aims at presenting a novel approach to evaluate the safety level of a battery-powered high speed catamaran. Following the Formal Safety Assessment procedure, the risk assessment of the considered ship was conducted leading to the identification of the involved hazards along with the estimation of their frequency and consequences thus allowing for the identification of the most severe hazards. Fault tree analysis is carried out for and the identified top events followed by an event tree analysis to estimate the risk and safety level of the vessel. Furthermore, a cost-benefit assessment is conducted to evaluate the financial impact of selected risk control options. The derived results indicate that the application of battery power systems for high speed ferries exhibits low and acceptable accident frequencies. It is also supported the current regulation to carry out mandatory risk assessment for battery-powered ships.

scholarly journals Seepage Safety Assessment of Concrete Gravity Dam Based on Matter-Element Extension Model and FDA

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 502 ◽  
Author(s):  
Xiaoling Wang ◽  
Hongling Yu ◽  
Peng Lv ◽  
Cheng Wang ◽  
Jun Zhang ◽  
...  
Keyword(s):  
Safety Assessment ◽  
Flood Control ◽  
Gravity Dam ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Concrete Gravity Dams ◽  
Extension Model ◽  
Infrastructure Project ◽  
The Stability ◽  
Criteria Importance

As an important infrastructure project, the concrete gravity dam plays an extremely important role in hydropower generation, irrigation, flood control, and other aspects. Seepage is an important factor affecting the stability of concrete gravity dams. Seepage safety assessment is of great significance to the safe operation of the dams. However, the existing seepage safety assessment models are not dynamic, and the correlation among indicators is often neglected and the overall seepage safety of the concrete gravity dams has not been considered. To solve these problems, this research proposes a dynamic matter-element extension (D-MEE) model. First, the D-MEE model is established through adroit integration of the matter-element extension (MEE) model and functional data analysis (FDA). Second, a dynamic criteria importance through the intercriteria correlation (D-CRITIC) method that can effectively consider the correlation among indicators is proposed to determine the weights. Third, the influence of different dam blocks on the overall seepage safety status is considered by constructing a spatial weight matrix. Finally, the proposed method is applied to the concrete gravity dam X in southwest China. The results show that the proposed method is effective and superior to the existing evaluation methods of seepage safety.

scholarly journals Risk Assessment of Aged Concrete Gravity Dam Subjected to Material Deterioration Under Seismic Excitation

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Tahmina Tasnim Nahar ◽  
Anh-Tuan Cao ◽  
Dookie Kim
Keyword(s):  
Mathematical Model ◽  
Risk Assessment ◽  
Seismic Risk ◽  
Fragility Curves ◽  
Seismic Excitation ◽  
Gravity Dam ◽  
Specific Time ◽  
Concrete Gravity Dam ◽  
Fragility Function ◽  
Cumulative Absolute Velocity

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) depending 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.

Risk Assessment Method and Protection Goals of High Concrete Gravity Dam Subjected to Far-Field Underwater Nuclear Explosion

2013 ◽  
Vol 871 ◽  
pp. 21-26 ◽  
Author(s):  
Lu Lu ◽  
Xin Li ◽  
Jing Zhou
Keyword(s):  
Risk Assessment ◽  
Nuclear Explosion ◽  
Focal Point ◽  
Assessment Method ◽  
Assessment Model ◽  
Far Field ◽  
Concrete Gravity Dam ◽  
Damage State ◽  
Security Problem ◽  
Protection Goals

The nucleus threat and hydraulic engineering's security problem are two focal point problems. At present, a new problem associated with the two problems has not systematically investigated and full understanding. This paper propose that the damage spectrum is used to predict the damage state of the concrete dam subject to far-field underwater nuclear explosion, and the environmental pollution factor is added in the risk assessment model. Finally, the protection design targets is mathematical described.

Assessment of the Applicability of Pushover Analysis for a Concrete Gravity Dam

2018 ◽  
Vol 9 (5) ◽  
pp. 181
Author(s):  
Machach Laila ◽  
Mouzzoun Mouloud ◽  
Moustachi Oum El Khaiat ◽  
Taleb Ali
Keyword(s):  
Pushover Analysis ◽  
Gravity Dam ◽  
Concrete Gravity Dam

SEISMIC RISK ASSESSMENT AND REDUCTION IN ITALY

2019 ◽  
Vol 1 (Special Issue on First SACEE'19) ◽  
pp. 55-75
Author(s):  
Fabio Sabetta
Keyword(s):  
Risk Assessment ◽  
Seismic Risk ◽  
Safety Assessment ◽  
Public Funding ◽  
Tax Incentives ◽  
Technical Training ◽  
Disaster Prevention ◽  
Existing Buildings ◽  
Seismic Risk Assessment ◽  
Post Disaster

In this paper, the main features of the policies adopted in Italy for seismic risk reduction are discussed. Particular attention is given to the Pre-disaster prevention activities such as the implementation of the building code, the seismic risk assessment for a priority scale of intervention, tax incentives and public funding for the vulnerability reduction of the existing buildings, information to population and school education, technical training of experts. The phases of response and post-disaster activities, including emergency management, search and rescue, loss scenarios, and safety assessment of buildings, are also discussed taking example from the most recent devastating earthquakes in Italy (L.Aquila 2009, Amatrice 2016).

Sign in / Sign up

Export Citation Format

Share Document