scholarly journals Seismic vulnerability of above-ground storage tanks with unanchored support conditions for Na-tech risks based on Gaussian process regression

2020 ◽  
Vol 18 (15) ◽  
pp. 6883-6906
Author(s):  
Hoang Nam Phan ◽  
Fabrizio Paolacci ◽  
Rocco Di Filippo ◽  
Oreste S. Bursi
Keyword(s):  
Gaussian Process ◽  
Earthquake Engineering ◽  
Storage Tank ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Gaussian Process Regression ◽  
System Response ◽  
Fe Model ◽  
Demand Model ◽  
Component Level

AbstractThis paper aims to investigate the seismic vulnerability of an existing unanchored steel storage tank ideally installed in a refinery in Sicily (Italy), along the lines of performance-based earthquake engineering. Tank performance is estimated by means of component-level fragility curves for specific limit states. The assessment is based on a framework that relies on a three-dimensional finite element (3D FE) model and a low-fidelity demand model based on Gaussian process regression, which allows for cheaper simulations. Moreover, to approximate the system response corresponding to the random variation of both peak ground acceleration and liquid filling level, a second-order design of experiments method is adopted. Hence, a parametric investigation is conducted on a specific existing unanchored steel storage tank. The relevant 3D FE model is validated with an experimental campaign carried out on a shaking table test. Special attention is paid to the base uplift due to significant inelastic deformations that occur at the baseplate close to the welded baseplate-to-wall connection, offering extensive information on both capacity and demand. As a result, the tank performance is estimated by means of component-level fragility curves for the aforementioned limit state which are derived through Monte Carlo simulations. The flexibility of the proposed framework allows fragility curves to be derived considering both deterministic and random filling levels. The comparison of the seismic vulnerability of the tank obtained with probabilistic and deterministic mechanical models demonstrates the conservatism of the latter. The same trend is also exhibited in terms of risk assessment.

Conditioned Simulation of Ground-Motion Time Series at Uninstrumented Sites Using Gaussian Process Regression

2021 ◽  
Author(s):  
Aidin Tamhidi ◽  
Nicolas Kuehn ◽  
S. Farid Ghahari ◽  
Arthur J. Rodgers ◽  
Monica D. Kohler ◽  
...  
Keyword(s):  
Time Series ◽  
Gaussian Process ◽  
Ground Motion ◽  
San Francisco ◽  
Earthquake Engineering ◽  
Seismic Analysis ◽  
Ground Motions ◽  
Free Field ◽  
Gaussian Process Regression ◽  
Motion Time

ABSTRACT Ground-motion time series are essential input data in seismic analysis and performance assessment of the built environment. Because instruments to record free-field ground motions are generally sparse, methods are needed to estimate motions at locations with no available ground-motion recording instrumentation. In this study, given a set of observed motions, ground-motion time series at target sites are constructed using a Gaussian process regression (GPR) approach, which treats the real and imaginary parts of the Fourier spectrum as random Gaussian variables. Model training, verification, and applicability studies are carried out using the physics-based simulated ground motions of the 1906 Mw 7.9 San Francisco earthquake and Mw 7.0 Hayward fault scenario earthquake in northern California. The method’s performance is further evaluated using the 2019 Mw 7.1 Ridgecrest earthquake ground motions recorded by the Community Seismic Network stations located in southern California. These evaluations indicate that the trained GPR model is able to adequately estimate the ground-motion time series for frequency ranges that are pertinent for most earthquake engineering applications. The trained GPR model exhibits proper performance in predicting the long-period content of the ground motions as well as directivity pulses.

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.

scholarly journals Seismic vulnerability assessment and fragility curves for a multistorey gallery arch bridge

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Vinay Shimpi ◽  
Madappa V. R. Sivasubramanian ◽  
S. B. Singh ◽  
D. Kesavan Periyasamy
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Nonlinear Dynamic Analysis ◽  
Ambient Vibration ◽  
Stone Masonry ◽  
Mode Shapes ◽  
Fe Model ◽  
Masonry Arch ◽  
Arch Bridge ◽  
Railway Line

AbstractThe masonry bridges on the Kalka Shimla Mountain Railway line, which have multiple arch galleries in the form of Roman aqueducts, are spectacular. The Kalka Shimla Mountain Railway line is situated in severe seismic zones (Indian Standard 1893:2016). This research assesses the seismic vulnerability of masonry arch Bridge No. 541 situated on the Kalka Shimla Mountain Railway line. This bridge is the tallest on the route. In particular, it assesses the seismic vulnerability of the bridge using finite element (FE) analysis. For this purpose, an FE model for the bridge is developed using the ABAQUS FE-based environment. The experimental field study conducted on the bridge using an ambient vibration test (AVT) and dynamic parameters (frequency and mode shapes) is evaluated by operational modal analysis (OMA). Further, the FE model is updated by modifying the elastic mechanical property of the stone masonry to match the analytical modal frequency with the results of the AVT and OMA. The updated model is then used to perform a pushover analysis and nonlinear dynamic analysis to estimate the seismic performance of the bridge. Furthermore, fragility curves are developed for the bridge to estimate the damage state for specific seismicity. The study shows that the bridge is vulnerable to Zone IV seismicity and needs some retrofitting in specific locations such as the pier–abutment joints.

scholarly journals Fragility Analysis of Gantry Crane Subjected to Near-Field Ground Motions

2020 ◽  
Vol 10 (12) ◽  
pp. 4219
Author(s):  
Qihui Peng ◽  
Wenming Cheng ◽  
Hongyu Jia ◽  
Peng Guo
Keyword(s):  
Failure Probability ◽  
Structural Damage ◽  
Fragility Curves ◽  
Damage Control ◽  
Ground Motions ◽  
Near Field ◽  
Vertical Component ◽  
Gantry Crane ◽  
Fe Model ◽  
Demand Model

A gantry crane located in a near-field earthquake-prone area is selected in this paper as an example, and the nonlinear finite element (FE) model is used considering the material nonlinearity including plastic hinges and the second order (P − Δ ) effect with a comprehensive consideration of the components including sill beams, support beams, legs, and trolley girders. The local displacement ratio (LDR) and deflection ratio (DR) are proposed as demand measures (DMs) of the gantry crane, which are utilized to construct a probabilistic seismic demand model (PSDM). Then, the capacity limit states for the gantry crane are defined in this study by performing pushover analysis (POA), known as serviceability, damage control, and collapse prevention, respectively. Moreover, the operating capacity of the crane during an earthquake is further investigated and quantified by operating seismic peak ground acceleration, which is defined as the maximum acceleration when the failure probability is 50%. Finally, the fragility curves and the failure probability of the gantry crane are derived by the above definitions, all of which are pioneering in the seismic design of gantry cranes subjected to near-field ground motions. Some major conclusions are drawn that the horizontal component of an earthquake has a more notable effect on the structural damage of the gantry crane compared to the vertical component, and incremental dynamic analysis can take seismic uncertainty into account and quantify the deformation of gantry crane in more detail.

Seismic Fragility Assessment of Concrete Bridge Pier Reinforced with Superelastic Shape Memory Alloy

2015 ◽  
Vol 31 (3) ◽  
pp. 1515-1541 ◽  
Author(s):  
A. H. M. Muntasir Billah ◽  
M. Shahria Alam
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Plastic Hinge ◽  
Bridge Pier ◽  
Performance Criteria ◽  
Demand Model ◽  
Permanent Displacement ◽  
The Impact

In an attempt to reduce permanent displacement and damage, a hybrid reinforced concrete (RC) bridge pier configuration is considered in the present study. The plastic hinge region of the bridge pier is reinforced with superelastic shape memory alloy (SMA) and the remaining portion with regular steel. This paper focuses on fragility-based seismic vulnerability assessment for a SMA-RC bridge pier considering residual displacement, displacement ductility, and performance criteria as the demand parameters. Fragility curves are developed to assess the relative vulnerability of a SMA-RC bridge pier and a conventional steel-RC bridge pier using probabilistic seismic demand model (PSDM). The fragility curves are developed with a suite of 20 near-fault ground motions using incremental dynamic analysis. The fragility curves provide insight into the failure probability of the bridge piers and aid in expressing the impact of SMA on the bridge pier vulnerability.

scholarly journals Seismic Fragility Analysis of Structures Based on Adaptive Gaussian Process Regression Metamodel

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Yanjie Xiao ◽  
Feng Yue ◽  
Xun'an Zhang
Keyword(s):  
Gaussian Process ◽  
Adaptive Sampling ◽  
Structural Parameters ◽  
Fragility Curves ◽  
Estimation Error ◽  
Time History ◽  
Gaussian Process Regression ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
Stochastic Seismic Response

Metamodel-based seismic fragility analysis methods can overcome the challenge of high computational costs of problems considering the uncertainties of earthquakes and structural parameters; however, the accuracy of metamodels is difficult to control. To enhance the efficiency of analyses without compromising accuracy, a metamodeling method using Gaussian process regression (GPR) and active learning (AL) for seismic fragility analysis is proposed. In this method, a GPR metamodel is built to estimate the stochastic seismic response of a structure, in which the record-to-record variability is considered as in the dual-metamodel-based fragility analysis approach. The metamodel can also predict the estimation error. Taking advantage of this ability, we present an AL strategy for adaptive sampling, so that the metamodel can be improved adaptively according to the problem. Using this metamodel and Monte Carlo simulation, seismic fragility curves can be obtained with a small number of calls for time history analysis. To verify its effectiveness, the proposed method was applied to three examples of nonlinear structures and compared with existing methods. The results show that this method has high computational efficiency and can ensure the accuracy of fragility curves without making the metamodel globally accurate.

Sliding Response of Unanchored Steel Storage Tanks Subjected to Seismic Loading

2019 ◽  
Author(s):  
Bledar Kalemi ◽  
Muhammad Farhan ◽  
Daniele Corritore
Keyword(s):  
Seismic Vulnerability ◽  
Failure Modes ◽  
Fragility Curves ◽  
Vertical Component ◽  
Friction Model ◽  
Fe Model ◽  
Storage Tanks ◽  
Damage State ◽  
Industrial Installation ◽  
Critical Components

Abstract Steel storage tanks are critical components of an industrial installation due to their high seismic vulnerability and containment of hazardous materials. Failure of a which, may lead to loss of containment (LOC) triggering domino effects such as explosion, environmental pollution, loss of functionality and disruption of business. Past earthquakes have demonstrated different type of failure modes in steel storage tanks. Although there are plenty of studies related to different failure modes like elephant foot buckling or tank uplifting, there are very few efforts on the sliding behavior of tank. Large displacements caused by the tank sliding can lead to pipe detachment and release of hazardous material which might cause damage propagation. Consequently, this damage state is very important for the Quantitative Seismic Risk Assessment of industrial plants. In order to enumerate the sliding displacement of unanchored steel storage tanks, a simplified numerical model realized with OpenSees platform is proposed. The friction model used in OpenSees is calibrated with the results obtained from ABAQUS FE model. Sliding response of tanks with different D/H ratio is analyzed using the simplified model. Fragility curves for the tank sliding damage state are analytically evaluated for different D/H ratio of the tank using the “cloud method”. Finally, a parametric study is conducted in order to comprehend the influence of different parameters on the sliding behavior such as friction coefficient, tank filling level and the influence of the vertical component of ground motions.

scholarly journals GNDT II level approach for seismic vulnerability assessment of Unreinforced Masonry (URM) building stock

2015 ◽  
Vol 3 ◽  
pp. 21-27 ◽  
Author(s):  
Manjip Shakya
Keyword(s):  
Earthquake Engineering ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Vulnerability Index ◽  
Seismic Intensity ◽  
Unreinforced Masonry ◽  
Physical Damage ◽  
Building Stock ◽  
Engineering Research ◽  
Evaluation Approach

Unreinforced Masonry (URM) structures, such as historic buildings, traditional buildings and ordinary buildings, exist all over the world and constitute a relevant part of the cultural heritage of humanity. Their protection against earthquakes is a topic of great concern among the earthquake engineering research community. This concern mainly arises from the strong damage or complete loss suffered by these types of structures when subjected to earthquake and also from the need and interest to preserve them as a built heritage. This paper initially presents a methodology for assessing the seismic vulnerability of URM buildings based on vulnerability index evaluation approach. Moreover, this paper presents the correlation between vulnerability index and Macroseismic method to estimate the physical damage in relationship with seismic intensity. Finally, presents implementation of the methodology to construct vulnerability curves, fragility curves and estimate losses.

scholarly journals Seismic Vulnerability Assessment of Slender Masonry Structures

2015 ◽  
pp. 313-330
Author(s):  
Manjip Shakya ◽  
Humberto Varum ◽  
Romeu Vicente ◽  
Aníbal Costa
Keyword(s):  
Earthquake Engineering ◽  
Seismic Vulnerability ◽  
Evaluation Method ◽  
Fragility Curves ◽  
Vulnerability Index ◽  
Seismic Intensity ◽  
Masonry Structures ◽  
Physical Damage ◽  
Engineering Research ◽  
Index Evaluation

Existing slender masonry structures, such as Pagoda temples, towers, minarets and chimneys, exist all over the world and constitute a relevant part of the architectural and cultural heritage of humanity. Their protection against earthquakes is a topic of great concern among the earthquake engineering research community. This concern mainly arises from the strong damage or complete loss suffered by these types of structures when subjected to earthquake and also from the need and interest to preserve them. This chapter firstly presents a methodology for assessing the seismic vulnerability of slender masonry structures based on vulnerability index evaluation method. Secondly, presents the correlation between vulnerability index and Macroseismic method to estimate the physical damage in relationship with seismic intensity. Finally, presents implementation of the methodology to construct vulnerability curves, fragility curves and estimate losses.

A Kriging-Based Surrogate Model for Seismic Fragility Analysis of Unanchored Storage Tanks

2019 ◽  
Author(s):  
Hoang Nam Phan ◽  
Fabrizio Paolacci ◽  
Daniele Corritore ◽  
Nicola Tondini ◽  
Oreste S. Bursi
Keyword(s):  
Surrogate Model ◽  
Seismic Vulnerability ◽  
Numerical Models ◽  
Fragility Curves ◽  
Computational Cost ◽  
Three Dimensional ◽  
Shaking Table ◽  
Fe Model ◽  
Storage Tanks ◽  
Damage State

Abstract The seismic vulnerability of aboveground steel storage tanks has been dramatically proved during the latest seismic events, which demonstrates the need for reliable numerical models for vulnerability and risk assessments of storage facilities. While for anchored aboveground tanks, simplified models are nowadays available and mostly used for the seismic vulnerability assessment, in the case of unanchored tanks, the scientific community is still working on numerical models capable of reliably predicting the nonlinearity due to uplift and sliding mechanisms. In this paper, a surrogate model based on a Kriging approach is proposed for a case study of an unanchored tank, whose calibration is performed on a three-dimensional finite element (3D FE) model using a reliable design of experiments (DOE) method. The verification of the 3D FE model is also done through a shaking table campaign. The outcomes show the effectiveness of the proposed model to build fragility curves at a low computational cost of the critical damage state of the tank, i.e., the plastic rotation of the shell-to-bottom joint.

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