Simplified Expression for Seismic Fragility Estimation of Sliding-Dominated Equipment and Contents

2006 ◽  
Vol 22 (3) ◽  
pp. 709-732 ◽  
Author(s):  
Tara C. Hutchinson ◽  
Samit Ray Chaudhuri
Keyword(s):  
Fragility Curves ◽  
Input Parameter ◽  
Simple Expression ◽  
Seismic Fragility ◽  
Economic Losses ◽  
Distribution Profile ◽  
Damage State ◽  
Fragility Function ◽  
Daunting Task ◽  
Recent Earthquakes

Damage to small equipment and contents during seismic events has gained considerable attention following recent earthquakes, largely due to the potential for operational downtime, which results in significant economic losses. The estimation of losses from this interior building damage is a daunting task, due to the complexity of types of equipment and the randomness of their location within the structure. Nonetheless, a precursor to calculating such losses is a reasonable association between structural and nonstructural (equipment or contents) demands. Cast in a probabilistic framework, such an association is best represented through the use of seismic fragility curves, where the probabilities of exceeding a given damage state is correlated with an input parameter. In this paper, analytically developed seismic fragility curves for various unattached equipment and contents are calculated and presented. The emphasis of the study is on rigid scientific equipment and contents, which are often placed on the surface of ceramic laboratory benches in science laboratories or other buildings. Only uniaxial seismic excitation is considered to provide insight into the form of the fragility function. Generalized fragility curves are then developed and a simple expression is presented, which is envisioned to be very useful from a design perspective. The usefulness of the proposed expression is illustrated via a simple numerical example coupled with a design code-specified horizontal acceleration distribution profile for an example building structure.

scholarly journals Performance Assessment of Interaction Soil Pile Structure Using the Fragility Methodology

2021 ◽  
Vol 7 (2) ◽  
pp. 376-398
Author(s):  
Guettafi Nesrine ◽  
Yahiaoui Djarir ◽  
Abbeche Khelifa ◽  
Bouzid Tayeb
Keyword(s):  
Axial Load ◽  
Fragility Curves ◽  
Pushover Analysis ◽  
Nonlinear Static Analysis ◽  
Seismic Fragility ◽  
Damage State ◽  
Steel Ratio ◽  
Lateral Capacity ◽  
And Performance ◽  
Loose Medium

This study aimed to investigate whether the seismic fragility and performance of interaction soil-pile-structure (ISPS) were affected by different parameters:  axial load, a section of the pile, and the longitudinal steel ratio of the pile were implanted in different type of sand (loose, medium, dense). In order to better understand the ISPS phenomena, a series of nonlinear static analysis have been conducted for two different cases, namely: (i) fixed system and (ii) ISPS system, to get the curves of the capacity of every parameter for developing the fragility curve. After a comparison of the numerical results of pushover analysis and fragility curves, the results indicate that these parameters are significantly influenced on lateral capacity, ductility and seismic fragility on the ISPS. The increasing in the axial load exhibit high probabilities of exceeding the damage state. The increase in pile section and longitudinal steel ratio, the effect of probability damage (low and high) are not only related to the propriety geometrically, but also related to the values of ductility and lateral capacity of the system. Doi: 10.28991/cej-2021-03091660 Full Text: PDF

scholarly journals Seismic Fragility Assessment of Steel Liquid Storage Tanks

2015 ◽  
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.

Axial Capacity Evaluation for Typical Suspended Ceiling Joints

2016 ◽  
Vol 32 (1) ◽  
pp. 547-565 ◽  
Author(s):  
Siavash Soroushian ◽  
Manos Maragakis ◽  
Craig Jenkins
Keyword(s):  
Experimental Data ◽  
Cyclic Loading ◽  
Fragility Curves ◽  
Experimental Studies ◽  
Analytical Models ◽  
Seismic Fragility ◽  
Axial Capacity ◽  
Capacity Evaluation ◽  
Recent Earthquakes ◽  
The University

In recent earthquakes, the failure of nonstructural elements, including ceiling systems, has resulted in costly damage, inoperable buildings, and endangered lives. Therefore, the need to understand how ceiling systems perform during an earthquake is becoming increasingly important. However, few studies have been conducted on suspension ceiling systems to identify where they are vulnerable. A series of suspension-ceiling component experiments were designed at the University of Nevada, Reno, using interlocking grid members, including 2-ft. and 4-ft. cross tees. The test specimens were first subjected to monotonic and cyclic loading to obtain their failure capacities. Then several axial capacity fragility curves (not the seismic fragility curves of ceiling systems) were developed based on axial displacement capacities as well as strength capacities of interlocking ceiling joints in the absence of ceiling panels. Besides the experimental studies, a series of analytical models for ceiling joints were developed and validated using component experimental data.

scholarly journals Seismic Fragility Analysis of Poorly Built Timber Buildings in Yangon Slum Areas

2020 ◽  
Vol 15 (3) ◽  
pp. 407-415
Author(s):  
Khin Myat Kyaw ◽  
Chaitanya Krishna Gadagamma ◽  
Kyaw Kyaw ◽  
Hideomi Gokon ◽  
Osamu Murao ◽  
...  
Keyword(s):  
Fragility Curves ◽  
Load Test ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
State Matrix ◽  
Damage State ◽  
Ground Acceleration ◽  
Displacement Capacity ◽  
Pushover Curve ◽  
Slum Areas

In Yangon and the suburbs of Myanmar, timber-framed buildings are the popular choice of construction for residential purposes. Nearly 8% of the total population in Yangon live in the slums and slum-like areas where the dwellings are predominantly made of non-durable materials. Wood, jungle wood, and bamboo are used as the framework and corrugated galvanized iron sheets as walling and sheathing material. The seismic-resistance capacity of timber buildings in slum areas has never been approved based on experimental evidence. Therefore, this study aims to conduct a seismic fragility analysis for poorly built timber buildings by providing a suitable method through numerical and experimental approaches. Pull-over loading tests were conducted on selected buildings to assess their loading-displacement capacity. Further, numerical modeling was done using the Wallstat simulation tool, which is based on the discrete element method. The pushover curve was validated with the curve from the pull-over load test. Once the numerical model was confirmed, dynamic analysis was conducted for different peak ground acceleration (PGA) (g) values until the complete numerical collapse of the building. Three building configurations with three ranges of variable material properties were considered in this study. A primary damage state started at the low PGA value of 0.05 g, and it can be confirmed that the timber buildings that were studied, are vulnerable to earthquakes. The results based on qualitative analysis were accumulated to obtain the damage state matrix, which was then used to obtain the fragility curves.

scholarly journals Seismic fragility of suspended ceiling systems used in NZ based on component tests

2016 ◽  
Vol 49 (1) ◽  
pp. 45-63 ◽  
Author(s):  
Rajesh P. Dhakal ◽  
Gregory A. MacRae ◽  
Atefeh Pourali ◽  
Giacomo Paganotti
Keyword(s):  
Fragility Curves ◽  
System Capacity ◽  
Seismic Fragility ◽  
Simple Method ◽  
Component Failure ◽  
Critical Elements ◽  
System Fragility ◽  
Standards And Guidelines ◽  
Recent Earthquakes ◽  
Storey Building

Current standards and guidelines for the design and installation of perimeter-fixed suspended ceilings are briefly reviewed and a summary of common damage in recent earthquakes is provided. Component failure fragility curves have been derived following experiments on typical NZ suspended ceilings, considering loading in tension, compression and shear. A simple method to analyse perimeter-fixed ceilings using peak floor acceleration (PFA) is described, allowing for ceiling system fragility to be obtained from component fragilities. This is illustrated in an example of a 5 storey building. It was found that single rivet end-fixings and cross-tee connections were the most critical elements of the ceilings governing the system capacity. In the design examples it was shown that ceilings at different elevations of the structure showed different probabilities of failure and larger ceiling areas with heavier tiles were most susceptible to damage.

Damage State Identification and Seismic Fragility Evaluation of the Underground Tunnels

2015 ◽  
Vol 775 ◽  
pp. 274-278
Author(s):  
Thai Son Le ◽  
Jung Won Huh ◽  
Jin Hee Ahn ◽  
Achintya Haldar
Keyword(s):  
Fragility Curves ◽  
Sampling Technique ◽  
Latin Hypercube Sampling ◽  
Assessment Method ◽  
Maximum Likelihood Estimates ◽  
Seismic Fragility ◽  
Large Set ◽  
Earthquake Intensity ◽  
Damage State ◽  
Design Spectrum

An efficient seismic fragility assessment method is proposed for underground tunnel structures in this paper. The ground response acceleration method for buried structure (GRAMBS), an efficient quasi-static method considering soil-structure interaction (SSI) effect, is used in the proposed approach to estimate the dynamic response behavior of the underground tunnels. In addition, the pushover analyses are conducted to identify the damage states of tunnels and Latin Hypercube sampling technique is used to consider uncertainties in the design variables. A large set of artificially generated ground motions satisfying a design spectrum for specific earthquake intensity are generated and fragility curves are developed. The seismic fragility curves are represented by two-parameter lognormal distribution function and its two parameters, namely the median and log-standard deviation, are estimated using the maximum likelihood estimates method.

scholarly journals Seismic Fragility Analysis of Bridge System Based on Fuzzy Failure Criteria

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Leping Ren ◽  
Shuanhai He ◽  
Haoyun Yuan ◽  
Zhao Zhu
Keyword(s):  
Structural Damage ◽  
Fragility Curves ◽  
Failure Criteria ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
Actual Condition ◽  
Seismic Load ◽  
Analysis Method ◽  
Damage State ◽  
Bridge System

In the traditional bridge seismic fragility analysis, the criterion for judging the structural damage state is clear. That is to say, when the damage index exceeds a specific value, the structure is judged to enter the new damage state. However, the actual condition is that the boundary of structural damage is not clear but fuzzy. Taking a three-span V-shaped continuous girder bridge as an example, the damage process of the structure is described by fuzzy mathematics. Considering the uncertainties of ground motion and structure itself, a seismic fragility analysis method is established, which can consider the randomness of bridge itself, seismic load, and structural failure fuzziness simultaneously. Finally, the improved product of conditional marginal (I-PCM) method for fragility analysis of bridge system is further optimized and improved. The new improved method is used to form the seismic fragility curves of bridge structure system. The results show that it is possible to underestimate the potential seismic fragility of bridge components and system without considering the structural fuzzy failure criteria; the fragility curves formed by different membership functions are obviously different; the new system fragility analysis method can significantly improve the analysis accuracy.

scholarly journals Typological Damage Fragility Curves for Unreinforced Masonry Buildings affected by the 2009 L'Aquila, Italy Earthquake

2021 ◽  
Vol 15 (1) ◽  
pp. 117-134
Author(s):  
Maria Zucconi ◽  
Rachele Ferlito ◽  
Luigi Sorrentino
Keyword(s):  
Peak Ground Acceleration ◽  
Risk Mitigation ◽  
Fragility Curves ◽  
Relative Size ◽  
Unreinforced Masonry ◽  
Building Damage ◽  
Economic Losses ◽  
Structural Elements ◽  
Damage State ◽  
Ground Acceleration

Background: Seismic risk mitigation has become a crucial issue due to the great number of casualties and large economic losses registered after recent earthquakes. In particular, unreinforced masonry constructions built before modern seismic codes, common in Italy and in other seismic-prone areas, are characterized by great vulnerability. In order to implement mitigation policies, analytical tools are necessary to generate scenario simulations. Methods: Therefore, data collected during inspections after the 2009 L’Aquila, Italy earthquake are used to derive novel fragility functions. Compared to previous studies, data are interpreted accounting for the presence of buildings not inspected due to those being undamaged. An innovative building damage state is proposed and is based on the response of different structural elements recorded in the survey form: vertical structures, horizontal structures, stairs, roof, and partition walls. In the suggested formulation, the combination of their performance is weighted based on typical reparation techniques and on the relative size of the structural elements, estimated from a database of complete geometrical surveys developed specifically for this study. Moreover, the proposed building damage state estimates earthquake-related damage by removing the preexisting damage reported in the inspection form. Results: Lognormal fragility curves, in terms of building damage state grade as a function of typological classes and peak ground acceleration, derived maximizing their likelihood and their merits compared with previous studies are highlighted. Conclusion: The correction of the database to account for uninspected buildings delivers curves that are less “stiff” and reach the median for lower peak ground acceleration values. The building feature that influences most the fragility is the masonry quality.

scholarly journals Development of Seismic Fragility Curves of RC Infilled Frame Buildings in Jordan

2019 ◽  
Vol 281 ◽  
pp. 01012
Author(s):  
Hanan Al-Nimry
Keyword(s):  
Fragility Curves ◽  
Three Dimensional ◽  
Seismic Fragility ◽  
Damage State ◽  
Infilled Frame ◽  
Capacity Curves ◽  
Infill Panels ◽  
Frame Buildings ◽  
Three Dimensional Models ◽  
Stone Concrete

This article examines the seismic fragility of low- and mid-rise RC infilled frame buildings in Jordan comprising stone-concrete infill panels. Three dimensional models of 2, 4 and 6 story regular and irregular representative buildings were developed. Pushover analyses were performed to construct capacity curves of the model buildings. Four damage states were considered: slight, moderate, extensive and complete and damage state thresholds were assigned, using expert opinion, based on yield and ultimate spectral displacements of the capacity spectra. Sets of preliminary fragility curves were developed to quantify earthquake damage probabilities in terms of spectral displacements.

SEISMIC RISK AND RESILIENCE ASSESSMENT OF INDUSTRIAL FACILITIES: CASE STUDY ON A BLACK CARBON PLANT

2020 ◽  
Author(s):  
George Karagiannakis
Keyword(s):  
Seismic Risk ◽  
Numerical Models ◽  
Fragility Curves ◽  
Human Life ◽  
Mitigation Strategies ◽  
Economic Losses ◽  
Risk And Resilience ◽  
Industrial Plants ◽  
Plant Equipment

This paper deals with state of the art risk and resilience calculations for industrial plants. Resilience is a top priority issue on the agenda of societies due to climate change and the all-time demand for human life safety and financial robustness. Industrial plants are highly complex systems containing a considerable number of equipment such as steel storage tanks, pipe rack-piping systems, and other installations. Loss Of Containment (LOC) scenarios triggered by past earthquakes due to failure on critical components were followed by severe repercussions on the community, long recovery times and great economic losses. Hence, facility planners and emergency managers should be aware of possible seismic damages and should have already established recovery plans to maximize the resilience and minimize the losses. Seismic risk assessment is the first step of resilience calculations, as it establishes possible damage scenarios. In order to have an accurate risk analysis, the plant equipment vulnerability must be assessed; this is made feasible either from fragility databases in the literature that refer to customized equipment or through numerical calculations. Two different approaches to fragility assessment will be discussed in this paper: (i) code-based Fragility Curves (FCs); and (ii) fragility curves based on numerical models. A carbon black process plant is used as a case study in order to display the influence of various fragility curve realizations taking their effects on risk and resilience calculations into account. Additionally, a new way of representing the total resilience of industrial installations is proposed. More precisely, all possible scenarios will be endowed with their weighted recovery curves (according to their probability of occurrence) and summed together. The result is a concise graph that can help stakeholders to identify critical plant equipment and make decisions on seismic mitigation strategies for plant safety and efficiency. Finally, possible mitigation strategies, like structural health monitoring and metamaterial-based seismic shields are addressed, in order to show how future developments may enhance plant resilience. The work presented hereafter represents a highly condensed application of the research done during the XP-RESILIENCE project, while more detailed information is available on the project website https://r.unitn.it/en/dicam/xp-resilience.

Sign in / Sign up

Export Citation Format

Share Document