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

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.

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Vertical Seismic Effect on the Seismic Fragility of Large-Space Underground Structures

Advances in Civil Engineering ◽

10.1155/2019/9650294 ◽

2019 ◽

Vol 2019 ◽

pp. 1-17 ◽

Cited By ~ 1

Author(s):

Zhiming He ◽

Qingjun Chen

Keyword(s):

Peak Ground Acceleration ◽

Fragility Curves ◽

Underground Structure ◽

Seismic Effect ◽

Peak Ground Velocity ◽

Seismic Fragility ◽

Vertical Acceleration ◽

Underground Structures ◽

Ground Acceleration ◽

Large Space

The measured vertical peak ground acceleration was larger than the horizontal peak ground acceleration. It is essential to consider the vertical seismic effect in seismic fragility evaluation of large-space underground structures. In this research, an approach is presented to construct fragility curves of large-space underground structures considering the vertical seismic effect. In seismic capacity, the soil-underground structure pushover analysis method which considers the vertical seismic loading is used to obtain the capacity curve of central columns. The thresholds of performance levels are quantified through a load-drift backbone curve model. In seismic demand, it is evaluated through incremental dynamic analysis (IDA) method under the excitation of horizontal and vertical acceleration, and the soil-structure-interaction and ground motion characteristics are also considered. The IDA results are compared in terms of peak ground acceleration and peak ground velocity. To construct the fragility curves, the evolutions of performance index versus the increasing earthquake intensity are performed, considering related uncertainties. The result indicates that if we ignore the vertical seismic effect to the fragility assessment of large-space underground structures, the exceedance probabilities of damage of large-space underground structures will be underestimated, which will result in an unfavorable assessment result.

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

Earthquake Spectra ◽

10.1193/1.2220637 ◽

2006 ◽

Vol 22 (3) ◽

pp. 709-732 ◽

Cited By ~ 14

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.

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Seismic Fragility Curves for On-Grade Steel Tanks

Earthquake Spectra ◽

10.1193/1.1586140 ◽

2000 ◽

Vol 16 (4) ◽

pp. 801-815 ◽

Cited By ~ 51

Author(s):

Michael J. O'Rourke ◽

Pak So

Keyword(s):

Fragility Curves ◽

Damage State ◽

Ground Acceleration ◽

Technical Literature ◽

Ground Shaking ◽

Liquid Storage ◽

Damage States ◽

Earthquake Loss ◽

Steel Tanks ◽

Grade Steel

The study reported herein attempts to characterize the seismic behavior of cylindrical on-grade, steel liquid storage tanks subject to the ground shaking hazard. The behavior is quantified by fragility curves that resulted from an analysis of the reported performance of over 400 tanks in nine separate earthquake events. The damage states used herein to characterize damage (i.e., slight, moderate, etc.) are intended to mirror damage state descriptions in the HAZUS Earthquake Loss Estimation Methodology. The amount of ground shaking is quantified by the peak ground acceleration (PGA) at the site. The influence of the tank's height to diameter ratio, H/D, as well as the relative amount of stored contents, % Full, are investigated and were found to have had a significant effect upon tank seismic performance. Finally, the fragility curves developed herein are compared to corresponding relations currently available in the technical literature.

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Seismic Vulnerability Assessment of a Reinforced Concrete Building Located in India

International Journal of Innovative Technology and Exploring Engineering - Special Issue ◽

10.35940/ijitee.k1059.09811s19 ◽

2019 ◽

Vol 8 (11S) ◽

pp. 310-314

Keyword(s):

Vulnerability Assessment ◽

Seismic Vulnerability ◽

Fragility Curves ◽

Equivalent Linearization ◽

Spectral Acceleration ◽

Damage State ◽

Ground Acceleration ◽

Seismic Vulnerability Assessment ◽

Performance Point ◽

Damage States

Over the recent years the natural disaster especially due to the earthquake effect on buildings increases which causes loss of life and property in many places all over the world. The latest development leads to finding the direct losses and damage states of the buildings for various intensities of earthquake ground motions. In the present study, seismic vulnerability assessment was done for a medium rise building (G+5). The design peak ground acceleration of 0.16g and 0.36g were considered for the risk assessment. The nonlinear static pushover analysis was done to fine the performance point, spectral acceleration and corresponding spectral acceleration by Equivalent Linearization (EL) method given by Federal Emergency Management Agency (FEMA-440). The four damage states such as slight, moderate, extreme and collapse has been considered as per HAZUS-MR4. The seismic vulnerability in terms of fragility curves was developed to evaluate the damage probabilities based on HAZUS methodology. The discrete and cumulative damage probability was found for all the damage states of the building which shows the building at 0.16g experience slight damage whereas at 0.36g the moderate damage state equally becomes predominant.

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Mobile home fragility curves

Earthquake Spectra ◽

10.1177/87552930211057583 ◽

2021 ◽

pp. 875529302110575

Author(s):

Bruce Maison ◽

John Eidinger

Keyword(s):

Peak Ground Acceleration ◽

Fragility Curves ◽

Seismic Fragility ◽

Risk Modeling ◽

Mobile Home ◽

Ground Acceleration ◽

Intensity Measures ◽

Modeling Methodology ◽

Manufactured Homes ◽

Support Conditions

Seismic fragility of mobile (manufactured) homes is investigated. Compiled is a catalog of home performance in past earthquakes. Intensity measures causing damage are characterized by peak ground acceleration and velocity. Damage is defined as when the home is knocked out of position necessitating repairs and re-installation. Four categories of support conditions are identified: unanchored, tie-downs, proprietary systems, and perimeter wall foundations. Suggested fragility curves for unanchored homes and homes with tie-downs are derived from computer simulations. As a benchmark, a fragility curve for proprietary and perimeter wall systems is taken as the same as that for conventional wood homes. Shortcomings of using tie-down and proprietary systems in high seismic zones are discussed. The suggested fragility curves account for the different categories of support conditions thereby representing advancement to those in the Hazus national standardized risk modeling methodology.

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

Journal of Disaster Research ◽

10.20965/jdr.2020.p0407 ◽

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.

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An Optimized Procedure to Estimate the Economic Seismic Losses of Existing Reinforced Concrete Buildings due to Seismic Damage

Buildings ◽

10.3390/buildings8100144 ◽

2018 ◽

Vol 8 (10) ◽

pp. 144 ◽

Cited By ~ 3

Author(s):

Marco Vona ◽

Benedetto Manganelli ◽

Sabina Tataranna ◽

Angelo Anelli

Keyword(s):

Seismic Risk ◽

Seismic Vulnerability ◽

Residential Buildings ◽

Fragility Curves ◽

Building Damage ◽

Mitigation Strategies ◽

Insurance Companies ◽

Economic Losses ◽

Risk Level ◽

Cost Ratio

The latest Italian seismic events have highlighted a high discrepancy between the potential destructiveness of an earthquake and the consequent economic losses due to damage to buildings. The main reason for this mismatch is the high number of vulnerable residential buildings or the low-to-medium vulnerability of buildings that are reaching the ends of their service lives. Awareness of the economic impact of seismic vulnerability should be a matter of primary interest for public administrations, private and insurance companies, banks, owners, and professionals, despite operating at different territorial levels and with different objectives. Quantification of the expected monetary consequence of seismic vulnerability, in terms of the probable cost of repairing earthquake damage, plays a key role in defining new and more effective seismic risk mitigation strategies. Retrofitting strategies based on intervention priority defined only according to the structural seismic risk level of buildings are incorrect. These strategies neglect several important issues, such as the financial losses caused by building damage. A new procedure for estimating the expected seismic direct economic losses resulting from building damage (repair/replacement measures) is proposed and applied. The fundamental roles of analytical fragility curves and cost ratio functions in the new procedure are highlighted.

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Sistem Informasi Geografis (SIG) untuk Zonasi Daerah Bahaya Kerusakan Bangunan Akibat Gempa Bumi: Studi Kasus pada Kota Banda Aceh dan Sekitarnya

ComTech Computer Mathematics and Engineering Applications ◽

10.21512/comtech.v3i1.2463 ◽

2012 ◽

Vol 3 (1) ◽

pp. 645

Author(s):

Edy Irwansyah ◽

Iqbal S. ◽

M. Ikhsan ◽

R. I Made Oka Yoga

Keyword(s):

Peak Ground Acceleration ◽

Design Method ◽

Earthquake Hazard ◽

Building Damage ◽

Flow Diagram ◽

Ground Acceleration ◽

Analysis And Design ◽

Entity Relationship Diagram ◽

Surrounding Areas ◽

Banda Aceh

This study aims to develop a geographic information system software that has the ability to develop hazard area zoning of building damage due to earthquake, especially in Banda Aceh and the surrounding areas using peak ground acceleration (PGA) value approach. Analysis and design methods are implemented in this study. The analytical method consists of two stages, namely seismic data collection period 1973 - 2011 by magnitude more than 5 on the Richter scale and the calculation of earthquake acceleration on bedrock using the attenuation function of Crouse. The design method comprises several structured stages, which are designing: data flow diagram (DFD), entity relationship diagram (ERD), menus, screens, and state transition diagrams (STD). The main conclusions of this study is that a GIS -based local zoning of earthquake hazard risk can be built and developed with calculation and classification approach of the peak ground acceleration (PGA). In addition, there is a relationship significant spatial found by comparing the results with the zoning patterns of building damage in the earthquake of 2004.

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Fragility Curves for Residential Masonry Chimneys

Earthquake Spectra ◽

10.1193/021217eqs028ep ◽

2018 ◽

Vol 34 (3) ◽

pp. 1001-1023 ◽

Cited By ~ 3

Author(s):

Bruce Maison ◽

Brian McDonald

Keyword(s):

Tensile Strength ◽

Computer Simulations ◽

Peak Ground Acceleration ◽

Fragility Curves ◽

Steel Reinforcement ◽

Regions Of Interest ◽

Damage Functions ◽

Ground Acceleration ◽

Flexural Tensile Strength

Chimney behavior is studied via computer simulations to quantify the effects of specific parameters, including chimney height above roof, masonry flexural tensile strength, chimney section dimensions, vertical steel reinforcement, and chimney-house anchorage strength. All of these parameters are found to affect performance. Damage functions are formulated relating peak ground acceleration to the likelihood of extensive chimney damage. The functions offer a practical way to inform fragility curves, thereby better reflecting an individual chimney as well as chimney inventories in regions of interest.

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An extended stochastic method for seismic hazard estimation

Natural Hazards and Earth System Sciences Discussions ◽

10.5194/nhessd-3-7555-2015 ◽

2015 ◽

Vol 3 (12) ◽

pp. 7555-7586

Author(s):

A. K. Abd el-aal ◽

M. A. El-Eraki ◽

S. I. Mostafa

Keyword(s):

Seismic Hazard ◽

Ground Motion ◽

Earthquake Engineering ◽

Peak Ground Acceleration ◽

Risk Mitigation ◽

Stochastic Method ◽

Soil Conditions ◽

Seismic Sources ◽

Ground Acceleration ◽

Median Response

Abstract. In this contribution, we developed an extended stochastic technique for seismic hazard assessment purposes. This technique depends on the hypothesis of stochastic technique of Boore (2003) "Simulation of ground motion using the stochastic method. Appl. Geophy. 160:635–676". The essential characteristics of extended stochastic technique are to obtain and simulate ground motion in order to minimize future earthquake consequences. The first step of this technique is defining the seismic sources which mostly affect the study area. Then, the maximum expected magnitude is defined for each of these seismic sources. It is followed by estimating the ground motion using an empirical attenuation relationship. Finally, the site amplification is implemented in calculating the peak ground acceleration (PGA) at each site of interest. We tested and applied this developed technique at Cairo, Suez, Port Said, Ismailia, Zagazig and Damietta cities to predict the ground motion. Also, it is applied at Cairo, Zagazig and Damietta cities to estimate the maximum peak ground acceleration at actual soil conditions. In addition, 0.5, 1, 5, 10 and 20 % damping median response spectra are estimated using the extended stochastic simulation technique. The calculated highest acceleration values at bedrock conditions are found at Suez city with a value of 44 cm s−2. However, these acceleration values decrease towards the north of the study area to reach 14.1 cm s−2 at Damietta city. This comes in agreement with the results of previous studies of seismic hazards in northern Egypt and is found to be comparable. This work can be used for seismic risk mitigation and earthquake engineering purposes.

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