scholarly journals Comparison of ground motions estimated from prediction equations and from observed damage during the <i>M</i> = 4.6 1983 Liège earthquake (Belgium)

2013 ◽  
Vol 13 (8) ◽  
pp. 1983-1997 ◽  
Author(s):  
D. García Moreno ◽  
T. Camelbeeck
Keyword(s):  
Western Europe ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Ground Motions ◽  
Gravitational Acceleration ◽  
Prediction Equations ◽  
Epicentral Area ◽  
Moderate Earthquake ◽  
Spectral Accelerations ◽  
Observed Damage

Abstract. On 8 November 1983 an earthquake of magnitude 4.6 damaged more than 16 000 buildings in the region of Liège (Belgium). The extraordinary damage produced by this earthquake, considering its moderate magnitude, is extremely well documented, giving the opportunity to compare the consequences of a recent moderate earthquake in a typical old city of Western Europe with scenarios obtained by combining strong ground motions and vulnerability modelling. The present study compares 0.3 s spectral accelerations estimated from ground motion prediction equations typically used in Western Europe with those obtained locally by applying the statistical distribution of damaged masonry buildings to two fragility curves, one derived from the HAZUS programme of FEMA (FEMA, 1999) and another developed for high-vulnerability buildings by Lang and Bachmann (2004), and to a method proposed by Faccioli et al. (1999) relating the seismic vulnerability of buildings to the damage and ground motions. The results of this comparison reveal good agreement between maxima spectral accelerations calculated from these vulnerability and fragility curves and those predicted from attenuation law equations, suggesting peak ground accelerations for the epicentral area of the 1983 earthquake of 0.13–0.20 g (g: gravitational acceleration).

scholarly journals Ground motions in urban Los Angeles from the 2019 Ridgecrest earthquake sequence

2021 ◽  
pp. 875529302110039
Author(s):  
Filippos Filippitzis ◽  
Monica D Kohler ◽  
Thomas H Heaton ◽  
Robert W Graves ◽  
Robert W Clayton ◽  
...  
Keyword(s):  
Los Angeles ◽  
Ground Motion ◽  
Ground Motions ◽  
Earthquake Sequence ◽  
Motion Prediction ◽  
Ground Motion Prediction Equations ◽  
Prediction Equations ◽  
Ground Motion Prediction ◽  
Velocity Models ◽  
Spectral Accelerations

We study ground-motion response in urban Los Angeles during the two largest events (M7.1 and M6.4) of the 2019 Ridgecrest earthquake sequence using recordings from multiple regional seismic networks as well as a subset of 350 stations from the much denser Community Seismic Network. In the first part of our study, we examine the observed response spectral (pseudo) accelerations for a selection of periods of engineering significance (1, 3, 6, and 8 s). Significant ground-motion amplification is present and reproducible between the two events. For the longer periods, coherent spectral acceleration patterns are visible throughout the Los Angeles Basin, while for the shorter periods, the motions are less spatially coherent. However, coherence is still observable at smaller length scales due to the high spatial density of the measurements. Examining possible correlations of the computed response spectral accelerations with basement depth and Vs30, we find the correlations to be stronger for the longer periods. In the second part of the study, we test the performance of two state-of-the-art methods for estimating ground motions for the largest event of the Ridgecrest earthquake sequence, namely three-dimensional (3D) finite-difference simulations and ground motion prediction equations. For the simulations, we are interested in the performance of the two Southern California Earthquake Center 3D community velocity models (CVM-S and CVM-H). For the ground motion prediction equations, we consider four of the 2014 Next Generation Attenuation-West2 Project equations. For some cases, the methods match the observations reasonably well; however, neither approach is able to reproduce the specific locations of the maximum response spectral accelerations or match the details of the observed amplification patterns.

Seismic Investigation of Steel Pile Bents: I. Evaluation of Performance

2002 ◽  
Vol 18 (1) ◽  
pp. 121-142 ◽  
Author(s):  
Ayman A. Shama ◽  
John B. Mander ◽  
Blaise A. Blabac ◽  
Stuart S. Chen
Keyword(s):  
Seismic Behavior ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Ground Motions ◽  
Highway Bridges ◽  
Companion Paper ◽  
Experimental Program ◽  
Evaluation Of Performance ◽  
The Subject ◽  
Overall Performance

The main objective of this study is to assess the seismic vulnerability of a class of highway bridges existing in certain regions of the eastern and central states, where steel H-piles extends out of the soil to support the pier cap. During severe ground motions, the overall performance of the bridge will be governed by the local performance of the pile-to-cap beam connection. The scope of work was divided into several tasks as follows: (1) a theory was developed to predict the performance of the connection under lateral loading; (2) an initial experimental program was conducted to investigate the seismic behavior of the steel bents; (3) a retrofit strategy is proposed; (4) a second experimental study was carried out to validate the proposed retrofit method; and (5) fragility curves for such structures were developed. This paper deals with the first two tasks of the study. The other three tasks are the subject of a second companion paper (Shama 2002).

Seismic Fragilities of High-Voltage Substation Disconnect Switches

2019 ◽  
Vol 35 (4) ◽  
pp. 1559-1582
Author(s):  
Bai Wen ◽  
Mohamed A. Moustafa ◽  
Dai Junwu
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Ground Motions ◽  
Incremental Dynamic Analysis ◽  
Nonlinear Finite Element ◽  
Power Grids ◽  
Finite Element Models ◽  
Severe Damage ◽  
Substation Equipment ◽  
Motion Characteristics

Electrical substations and vital components, e.g., disconnect switches, experienced severe damage that caused blackouts during past earthquakes. To improve the seismic resiliency of power grids and use probabilistic decision-making frameworks, comprehensive fragility data for the different substation equipment are needed. The objective of this study is to investigate the seismic performance of and develop component and system fragility curves for a critical substation component: disconnect switches. The seismic vulnerability of two common switch types was evaluated and two operational configurations were considered. Detailed nonlinear finite element models for the full switches were calibrated using previous experimental data and used to conduct incremental dynamic analysis and carry out the fragility assessment. A total of 160 triaxial ground motions representing four sets of different ground motion characteristics were used. The switches’ fragility curves were developed and presented to be readily used for new substation design, prioritizing retrofit/maintenance activities and reliability assessment of power grids.

scholarly journals Seismic fragility of a highway bridge in Quebec retrofitted with natural rubber isolators

2014 ◽  
Vol 7 (4) ◽  
pp. 534-547
Author(s):  
G. H. Siqueira ◽  
D. H. Tavares ◽  
P. Paultre
Keyword(s):  
Natural Rubber ◽  
Seismic Isolation ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Ground Motions ◽  
Highway Bridge ◽  
Eastern Canada ◽  
Seismic Isolator ◽  
Rubber Bearing ◽  
Time Histories

This paper presents fragility curves for the evaluation of a highway bridge retrofitted with seismic isolator devices. The object of this study is the Chemin des Dalles bridge over Highway 55 located in Trois-Rivières in Quebec, Canada. A series of synthetic ground motions time histories compatible with eastern Canada are used to capture the uncertainties related to the hazard. The seismic isolator model represents natural rubber bearing placed under the longitudinal girders over the bents and the abutments of the bridge. NRB isolators are placed in these locations to uncouple the movement of the superstructure and the infrastructure, increasing the flexibility of the system and decreasing the forces transmitted to the infrastructure. Finally, a set of fragility curves for the as-built and retrofitted models are compared to evaluate the effectiveness of seismic isolation to decrease the seismic vulnerability of this bridge.

scholarly journals Evaluation of Seismic Vulnerability of Hospitals in the Tehran Metropolitan Area

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 54
Author(s):  
Setareh Ghaychi Afrouz ◽  
Alireza Farzampour ◽  
Zahra Hejazi ◽  
Masoud Mojarab
Keyword(s):  
Metropolitan Area ◽  
Structural Damage ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Health Care Systems ◽  
Ground Motions ◽  
Active Faults ◽  
The United States ◽  
Damage And Failure ◽  
Proactive Management

The Tehran metropolitan area is extremely vulnerable to earthquakes due to the location of its active faults and its dense population. Assessing the probable damage of a high magnitude earthquake on buildings and facilities relies on a precise structural survey, which has an empirical basis depending on historic ground motions. The probability of damage and failure in discrete limits based on different ground motions is estimated by fragility curves. Using the most matching fragility curves for buildings in Tehran, the vulnerability of the hospitals in the capital, as one of the most critical structures in crisis management of disasters, was investigated in this study. Subsequently, the existing fragility curves, developed for Tehran and the other seismic prone countries such as Japan and the United States, were compared considering the typology of Tehran’s hospitals. Finally, the possible damages for each hospital were calculated based on the most conservative fragility curve and the most pessimistic scenario, which were used to evaluate the seismic vulnerability of hospitals and health care systems for different damage states. After zoning the damage of therapeutic areas of Tehran, it was observed that at least 2% to 10% damage occurred in all hospitals of Tehran, and none of the healthcare centers would remain structurally undamaged after a strong earthquake with the moment magnitude of 7 or more. In addition, the healthcare buildings could be prone to significant structural damage, especially in southern parts, which necessitates proactive management plans for Tehran metropolitan area.

scholarly journals Fragility curves for Italian URM buildings based on a hybrid method

2021 ◽  
Author(s):  
A. Sandoli ◽  
G. P. Lignola ◽  
B. Calderoni ◽  
A. Prota
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Limit State ◽  
Ultimate Limit State ◽  
Masonry Building ◽  
Masonry Buildings ◽  
Seismic Behaviour ◽  
Building Stock ◽  
Ground Acceleration ◽  
Damage Scenario

AbstractA hybrid seismic fragility model for territorial-scale seismic vulnerability assessment of masonry buildings is developed and presented in this paper. The method combines expert-judgment and mechanical approaches to derive typological fragility curves for Italian residential masonry building stock. The first classifies Italian masonry buildings in five different typological classes as function of age of construction, structural typology, and seismic behaviour and damaging of buildings observed following the most severe earthquakes occurred in Italy. The second, based on numerical analyses results conducted on building prototypes, provides all the parameters necessary for developing fragility functions. Peak-Ground Acceleration (PGA) at Ultimate Limit State attainable by each building’s class has been chosen as an Intensity Measure to represent fragility curves: three types of curve have been developed, each referred to mean, maximum and minimum value of PGAs defined for each building class. To represent the expected damage scenario for increasing earthquake intensities, a correlation between PGAs and Mercalli-Cancani-Sieber macroseismic intensity scale has been used and the corresponding fragility curves developed. Results show that the proposed building’s classes are representative of the Italian masonry building stock and that fragility curves are effective for predicting both seismic vulnerability and expected damage scenarios for seismic-prone areas. Finally, the fragility curves have been compared with empirical curves obtained through a macroseismic approach on Italian masonry buildings available in literature, underlining the differences between the methods.

scholarly journals Challenges in Evaluating Seismic Collapse Risk for RC Buildings

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Jin Zhou ◽  
Zhelun Zhang ◽  
Tessa Williams ◽  
Sashi K. Kunnath
Keyword(s):  
Ground Motion ◽  
Seismic Vulnerability ◽  
Ground Motions ◽  
Primary System ◽  
Fragility Functions ◽  
Reinforced Concrete Frame ◽  
Ground Motion Selection ◽  
Concrete Frame ◽  
Frame Building ◽  
Seismic Collapse

AbstractThe development of fragility functions that express the probability of collapse of a building as a function of some ground motion intensity measure is an effective tool to assess seismic vulnerability of structures. However, a number of factors ranging from ground motion selection to modeling decisions can influence the quantification of collapse probability. A methodical investigation was carried out to examine the effects of component modeling and ground motion selection in establishing demand and collapse risk of a typical reinforced concrete frame building. The primary system considered in this study is a modern 6-story RC moment frame building that was designed to current code provisions in a seismically active region. Both concentrated and distributed plasticity beam–column elements were used to model the building frame and several options were considered in constitutive modeling for both options. Incremental dynamic analyses (IDA) were carried out using two suites of ground motions—the first set comprised site-dependent ground motions, while the second set was a compilation of hazard-consistent motions using the conditional scenario spectra approach. Findings from the study highlight the influence of modeling decisions and ground motion selection in the development of seismic collapse fragility functions and the characterization of risk for various demand levels.

scholarly journals Mechanics-based fragility curves for Italian residential URM buildings

2020 ◽  
Author(s):  
Marco Donà ◽  
Pietro Carpanese ◽  
Veronica Follador ◽  
Luca Sbrogiò ◽  
Francesca da Porto
Keyword(s):  
Reference Model ◽  
Fragility Curves ◽  
National Level ◽  
Building Stock ◽  
Damage Scenarios ◽  
Complex Evaluation ◽  
Proposed Model ◽  
2009 L’Aquila Earthquake ◽  
Damage States ◽  
Observed Damage

Abstract Seismic risk assessment at the territorial level is now widely recognised as essential for countries with intense seismic activity, such as Italy. Academia is called to give its contribution in order to synergically deepen the knowledge about the various components of this risk, starting from the complex evaluation of vulnerability of the built heritage. In line with this, a mechanics-based seismic fragility model for Italian residential masonry buildings was developed and presented in this paper. This model is based on the classification of the building stock in macro-typologies, defined by age of construction and number of storeys, which being information available at national level, allow simulating damage scenarios and carrying out risk analyses on a territorial scale. The model is developed on the fragility of over 500 buildings, sampled according to national representativeness criteria and analysed through the Vulnus_4.0 software. The calculated fragility functions were extended on the basis of a reference model available in the literature, which provides generic fragilities for the EMS98 vulnerability classes, thus obtaining a fragility model defined on the five EMS98 damage states. Lastly, to assess the reliability of the proposed model, this was used to simulate damage scenarios due to the 2009 L’Aquila earthquake. Overall, the comparison between model results and observed damage showed a good fit, proving the model effectiveness.

Seismic Risk Mitigation of Historical Masonry Towers by Means of Prestressing Devices

2010 ◽  
Vol 133-134 ◽  
pp. 843-848 ◽  
Author(s):  
Adolfo Preciado Quiroz ◽  
Silvio T. Sperbeck ◽  
Harald Budelmann ◽  
Gianni Bartoli ◽  
Elham Bazrafshan
Keyword(s):  
Seismic Risk ◽  
Seismic Vulnerability ◽  
Risk Mitigation ◽  
Numerical Models ◽  
Failure Mechanisms ◽  
Masonry Towers ◽  
Seismic Risk Mitigation ◽  
Historical Masonry ◽  
Observed Damage ◽  
And Behavior

This work presents the investigation of the efficiency of different prestressing devices as a rehabilitation measure for the seismic risk mitigation of historical masonry towers. As a first phase, the seismic vulnerability of theoretical masonry towers was assessed by means of numerical models validated with information from the literature, observed damage and behavior of these structures due to passed earthquakes (crack pattern and failure mechanisms), and mainly taking into account the engineering experience. Afterwards, the validated models were rehabilitated with different prestressing devices; analyzing the results and concluding which device or the combination of them improved in a better way the seismic performance of the masonry towers. Finally, the methodology will be applied in two historical masonry towers located in seismic areas; the medieval tower “Torre Grossa” of San Gimignano, Italy, and one of the bell towers of the Cathedral of Colima, Mexico.

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