Seismic Performance Evaluation of Liquid Storage Tanks Using Nonlinear Static Procedures

A simplified approach is presented for the seismic performance assessment of liquid storage tanks. The proposed methodology relies on a nonlinear static analysis, in conjunction with suitable “strength ratio-ductility-period” relationships, to derive the associated structural demand for the desired range of seismic intensities. In the absence of available relationships that are deemed fit to represent the nonlinear-elastic response of liquid storage tanks, several incremental dynamic analyses are performed for variable post-yield hardening ratios and periods in order to form a set of data that enables the fitting of the response. Following the identification of common modes of failure such as elephant's foot buckling (EFB), base plate plastic rotation, and sloshing wave damage, the aforementioned relationships are employed to derive the 16%, 50%, and 84% percentiles for each of the respective response parameters. Fragility curves are extracted for the considered failure modes, taking special care to appropriately quantify both the median and the dispersion of capacity and demand. A comparison with the corresponding results of incremental dynamic analysis (IDA) reveals that the pushover approach offers a reasonable agreement for the majority of failure modes and limit states considered.

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Fragility and robustness analysis of a multistorey RC building

Journal of the Croatian Association of Civil Engineers ◽

10.14256/jce.3036.2020 ◽

2021 ◽

Vol 73 (01) ◽

pp. 27-44

Keyword(s):

Fragility Curves ◽

Nonlinear Dynamic Analysis ◽

Robustness Analysis ◽

Nonlinear Static Analysis ◽

Limit States ◽

Element Loss ◽

Rc Building ◽

Frame System ◽

Nonlinear Static ◽

Storey Building

The robustness of a reinforced concrete (RC) five-storey building (frame system stiffened by walls) is analysed in the paper. A high ductility class structure is designed in accordance with structural Eurocodes. The response of the structure to eight different scenarios of the ground floor vertical element loss is analysed. Nonlinear Static Analysis (NSA) and Nonlinear Dynamic Analysis (NDA) methods are used for the robustness analysis. Fragility curves of the building are derived from statistical analysis of these results. The values obtained through NSA and NDA, damage limit states of the system, and fragility curves, are compared. The influence of the position of the removed element on robustness of the structure is also analysed.

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Seismic Fragility Assessment of Steel Liquid Storage Tanks

Volume 8: Seismic Engineering ◽

10.1115/pvp2015-45370 ◽

2015 ◽

Cited By ~ 4

Author(s):

Konstantinos Bakalis ◽

Dimitrios Vamvatsikos ◽

Michalis Fragiadakis

Keyword(s):

Failure Modes ◽

Fragility Curves ◽

Seismic Fragility ◽

Assessment Procedure ◽

Storage Tanks ◽

Component Level ◽

Damage State ◽

Liquid Storage ◽

Damage States ◽

Buckling Failure

A seismic fragility assessment procedure is developed for atmospheric steel liquid storage tanks. Appropriate system and component-level damage states are defined by identifying the failure modes that may occur during a strong ground motion. Special attention is paid to the elephant’s foot buckling failure mode, where the estimation of the associated capacity and demand requires thorough consideration within a probabilistic framework. A novel damage state is introduced to existing procedures with respect to the uncontrollable loss of containment scenario. Fragility curves are estimated by introducing both aleatory and epistemic sources of uncertainty, thus providing a comprehensive methodology for the seismic risk assessment of liquid storage tanks. The importance of dynamic buckling is acknowledged and the issue of non-sequential damage states is finally revealed.

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Performance Criteria for Liquid Storage Tanks and Piping Systems Subjected to Seismic Loading

Journal of Pressure Vessel Technology ◽

10.1115/1.4036916 ◽

2017 ◽

Vol 139 (5) ◽

Cited By ~ 16

Author(s):

Maria Vathi ◽

Spyros A. Karamanos ◽

Ioannis A. Kapogiannis ◽

Konstantinos V. Spiliopoulos

Keyword(s):

Failure Modes ◽

Low Cycle Fatigue ◽

Numerical Models ◽

Local Strain ◽

Performance Criteria ◽

Piping System ◽

Storage Tanks ◽

Limit States ◽

Liquid Storage ◽

Piping Systems

In this paper, performance criteria for the seismic design of industrial liquid storage tanks and piping systems are proposed, aimed at introducing those industrial components into a performance-based design (PBD) framework. Considering “loss of containment” as the ultimate damage state, the proposed limit states are quantified in terms of local quantities obtained from a simple and efficient earthquake analysis. Liquid storage tanks and the corresponding principal failure modes (elephant's foot buckling, roof damage, base plate failure, anchorage failure, and nozzle damage) are examined first. Subsequently, limit states for piping systems are presented in terms of local strain at specific piping components (elbows, Tees, and nozzles) against ultimate strain capacity (tensile and compressive) and low-cycle fatigue. Modeling issues for liquid storage tanks and piping systems are also discussed, compared successfully with available experimental data, and simple and efficient analysis tools are proposed, toward reliable estimates of local strain demand. Using the above reliable numerical models, the proposed damage states are examined in two case studies: (a) a liquid storage tank and (b) a piping system, both located in areas of high seismicity.

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Vulnerability-Based Design of Sliding Concave Bearings for the Seismic Isolation of Steel Storage Tanks

Volume 8: Seismic Engineering ◽

10.1115/pvp2016-63101 ◽

2016 ◽

Author(s):

Hoang Nam Phan ◽

Fabrizio Paolacci ◽

Silvia Alessandri ◽

Phuong Hoa Hoang

Keyword(s):

Liquid Steel ◽

Seismic Isolation ◽

Failure Modes ◽

Fragility Curves ◽

Time History ◽

Probability Of Failure ◽

Design Parameters ◽

Economic Losses ◽

Storage Tanks ◽

Isolation System

Liquid steel storage tanks are strategic structures for industrial facilities and have been widely used both in nuclear and non-nuclear power plants. Typical damage to tanks occurred during past earthquakes such as cracking at the bottom plate, elastic or elastoplastic buckling of the tank wall, failure of the ground anchorage system, and sloshing damage around the roof, etc. Due to their potential and substantial economic losses as well as environmental hazards, implementations of seismic isolation and energy dissipation systems have been recently extended to liquid storage tanks. Although the benefits of seismic isolation systems have been well known in reducing seismic demands of tanks; however, these benefits have been rarely investigated in literature in terms of reduction in the probability of failure. In this paper, A vulnerability-based design approach of a sliding concave bearing system for an existing elevated liquid steel storage tank is presented by evaluating the probability of exceeding specific limit states. Firstly, nonlinear time history analyses of a three-dimensional stick model for the examined case study are performed using a set of ground motion records. Fragility curves of different failure modes of the tank are then obtained by the well-known cloud method. In the following, a seismic isolation system based on concave sliding bearings is proposed. The effectiveness of the isolation system in mitigating the seismic response of the tank is investigated by means of fragility curves. Finally, an optimization of design parameters for sliding concave bearings is determined based on the reduction of the tank vulnerability or the probability of failure.

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Seismic Vulnerability Assessment of Liquid Storage Tanks Isolated by Sliding-Based Systems

Advances in Civil Engineering ◽

10.1155/2018/5304245 ◽

2018 ◽

Vol 2018 ◽

pp. 1-14 ◽

Cited By ~ 4

Author(s):

Alexandros Tsipianitis ◽

Yiannis Tsompanakis

Keyword(s):

Large Scale ◽

Seismic Vulnerability ◽

Base Isolation ◽

Cost Effective ◽

Storage Tanks ◽

Modes Of Failure ◽

Liquid Storage ◽

Near Fault Earthquakes ◽

Friction Pendulum ◽

The Cost

Liquid-filled tanks are effective storage infrastructure for water, oil, and liquefied natural gas (LNG). Many such large-scale tanks are located in regions with high seismicity. Therefore, very frequently base isolation technology has to be adopted to reduce the dynamic distress of storage tanks, preventing the structure from typical modes of failure, such as elephant-foot buckling, diamond-shaped buckling, and roof damage caused by liquid sloshing. The cost-effective seismic design of base-isolated liquid storage tanks can be achieved by adopting performance-based design (PBD) principles. In this work, the focus is given on sliding-based systems, namely, single friction pendulum bearings (SFPBs), triple friction pendulum bearings (TFPBs), and mainly on the recently developed quintuple friction pendulum bearings (QFPBs). More specifically, the study is focused on the fragility analysis of tanks isolated by sliding-bearings, emphasizing on isolators’ displacements due to near-fault earthquakes. In addition, a surrogate model has been developed for simulating the dynamic response of the superstructure (tank and liquid content) to achieve an optimal balance between computational efficiency and accuracy.

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Microstructural insights into the compressive failure of snow based on a peridynamic framework

10.5194/egusphere-egu2020-22435 ◽

2020 ◽

Author(s):

Jonas Ritter ◽

Henning Löwe ◽

Michael Zaiser

Keyword(s):

Computed Tomography ◽

Failure Modes ◽

Large Deformations ◽

Failure Mechanisms ◽

Elastic Response ◽

Problem Solution ◽

Compaction Bands ◽

Modes Of Failure ◽

Computed Tomography Images ◽

Non Local

<p>Highly-porous cohesive granular materials such as snow possess complex modes of failure. Apart from classical failure modes, they show microstructural failure and fragmentation associated with densification within a local, narrow zone. Therefore cracks may form and propagate even under compressive load (&#8216;anticracks&#8217;,&#8217;compaction bands&#8217;). Such failure modes are of importance in a range of geophysical contexts. For instance, they may control the release of snow slab avalanches and influence fracturing of porous rock formations. In the snow context, specific failure mechanisms of the ice matrix and their interplay with the microstructure geometry of snow are still poorly understood. Recently, X-ray computed tomography images have provided insights into snow microstructure and capability of directly simulating its elastic response by the finite element method (FEM). However, apart from thermodynamically driven healing processes the inelastic post-peak behaviour of the microstructure is controlled by localized damage, large deformations and internal contacts. As a result of the well-known limitations of FEM to capture these processes we use Peridynamics (PD) as a non-local continuum method to approach the problem. Due to its formulation, (micro)cracks and damage are emergent features of the problem solution that do not need to be known or located in advance. Furthermore, the Lagrangian character of the governing equations makes the method suitable for simulating large deformations. In this contribution we perform confined uniaxial compression simulations of snow microstructures within a peridynamic framework. Computed tomography images of snow specimen serve as a simulation data base. The obtained results show a novel insight into local failure of snow and allow a better comprehension of the underlying failure mechanisms. This study contributes to improve non-local macroscopic constitutive models for snow for future applications.</p>

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