Statistical Analysis of Bridge Damage Data from the 1994 Northridge, CA, Earthquake

1999 ◽  
Vol 15 (1) ◽  
pp. 25-54 ◽  
Author(s):  
Nesrin I. Basöz ◽  
Anne S. Kiremidjian ◽  
Stephanie A. King ◽  
Kincho H. Law
Keyword(s):  
Los Angeles ◽  
Ground Motion ◽  
Structural Characteristics ◽  
Fragility Curves ◽  
Cost Ratio ◽  
Repair Cost ◽  
Ground Acceleration ◽  
Damage Data ◽  
Bridge Damage ◽  
Observed Damage

This paper presents the significant findings from a study on damage to bridges during the January 17, 1994 Northridge, CA earthquake. The damage and repair cost data were compiled in a database for bridges in the Greater Los Angeles area. Observed damage data for all bridges were discriminated by structural characteristics. The analyses of data on bridge damage showed that concrete structures designed and built with older design standards were more prone to damage under seismic loading. Repair and/or reconstruction of collapsed structures formed seventy five percent of the total estimated repair cost. Peak ground acceleration values were also estimated at all bridge locations as part of this study. Empirical relationships between ground motion and bridge damage, and repair cost ratio were developed in the form of fragility curves and damage probability matrices, respectively. A comparison of the empirical and available ground motion-damage relationships demonstrated that the relationships that are currently in use do not correlate well to the observed damage.

scholarly journals Fragility estimation for global building classes using analysis of the Cambridge earthquake damage database (CEQID)

2021 ◽  
Author(s):  
Robin Spence ◽  
Sandra Martínez-Cuevas ◽  
Hannah Baker
Keyword(s):  
Fragility Curves ◽  
Resistance Index ◽  
Earthquake Damage ◽  
Ground Acceleration ◽  
Damage Level ◽  
Ground Motion Parameter ◽  
Geographical Regions ◽  
Concrete Building ◽  
Damage Data ◽  
Regional Comparisons

AbstractThis paper describes CEQID, a database of earthquake damage and casualty data assembled since the 1980s based on post-earthquake damage surveys conducted by a range of research groups. Following 2017–2019 updates, the database contains damage data for more than five million individual buildings in over 1000 survey locations following 79 severely damaging earthquakes worldwide. The building damage data for five broadly defined masonry and reinforced concrete building classes has been assembled and a uniform set of six damage levels assigned. Using estimated peak ground acceleration (PGA) for each survey location based on USGS Shakemap data, a set of lognormal fragility curves has been developed to estimate the probability of exceedance of each damage level for each class, and separate fragility curves for each of five geographical regions are presented. A revised set of fragility curves has also been prepared in which the bias in the curve resulting from the uncertainty in the ground motion parameter has been removed. The uncertainty in the fragility curves is evaluated and discussed and the curves are compared with those from other studies. A resistance index for each class of building is developed and cross-regional comparisons using this resistance index are presented.

Repeatable Source, Path, and Site Effects from the 2019 M 7.1 Ridgecrest Earthquake Sequence

2020 ◽  
Vol 110 (4) ◽  
pp. 1530-1548 ◽  
Author(s):  
Grace A. Parker ◽  
Annemarie S. Baltay ◽  
John Rekoske ◽  
Eric M. Thompson
Keyword(s):  
Los Angeles ◽  
Ground Motion ◽  
Site Response ◽  
Ground Motions ◽  
Warning System ◽  
Site Amplification ◽  
Earthquake Sequence ◽  
Ground Acceleration ◽  
Small Magnitude ◽  
Earthquake Early Warning System

ABSTRACT We use a large instrumental dataset from the 2019 Ridgecrest earthquake sequence (Rekoske et al., 2019, 2020) to examine repeatable source-, path-, and site-specific ground motions. A mixed-effects analysis is used to partition total residuals relative to the Boore et al. (2014; hereafter, BSSA14) ground-motion model. We calculate the Arias intensity stress drop for the earthquakes and find strong correlation with our event terms, indicating that they are consistent with source processes. We look for physically meaningful trends in the partitioned residuals and test the ability of BSSA14 to capture the behavior we observe in the data. We find that BSSA14 is a good match to the median observations for M>4. However, we find bias for individual events, especially those with small magnitude and hypocentral depth≥7  km, for which peak ground acceleration is underpredicted by a factor of 2.5. Although the site amplification term captures the median site response when all sites are considered together, it does not capture variations at individual stations across a range of site conditions. We find strong basin amplification in the Los Angeles, Ventura, and San Gabriel basins. We find weak amplification in the San Bernardino basin, which is contrary to simulation-based findings showing a channeling effect from an event with a north–south azimuth. This and an additional set of ground motions from earthquakes southwest of Los Angeles suggest that there is an azimuth-dependent southern California basin response related to the orientation of regional structures when ground motion from waves traveling south–north are compared with those in the east–west direction. These findings exhibit the power of large, spatially dense ground-motion datasets and make clear that nonergodic models are a way to reduce bias and uncertainty in ground-motion estimation for applications like the U.S. Geological Survey National Seismic Hazard Model and the ShakeAlert earthquake early warning System.

Post-earthquake Prioritization of Bridge Inspections

2007 ◽  
Vol 23 (1) ◽  
pp. 131-146 ◽  
Author(s):  
R. T. Ranf ◽  
M. O. Eberhard ◽  
S. Malone
Keyword(s):  
Ground Motion ◽  
Pacific Northwest ◽  
Epicentral Distance ◽  
Fragility Curves ◽  
Washington State ◽  
Motion Processing ◽  
The Pacific ◽  
Bridge Damage ◽  
Washington State Department ◽  
Prioritization Strategy

Bridge damage reports from the 2001 Nisqually earthquake were correlated with estimates of ground-motion intensity at each bridge site (obtained from ShakeMaps) and with bridge properties listed in the Washington State Bridge Inventory. Of the ground-motion parameters considered, the percentage of bridges damaged correlated best with the spectral acceleration at a period of 0.3 s. Bridges constructed before the 1940s, movable bridges, and older trusses were particularly vulnerable. These bridge types were underestimated by the HAZUS procedure, which categorizes movable bridges and older trusses as “other” bridges. An inspection prioritization strategy was developed that combines ShakeMaps, the bridge inventory and newly developed fragility curves. For the Nisqually earthquake, this prioritization strategy would have made it possible to identify 80% of the moderately damaged bridges by inspecting only 481 (14%) of the 3,407 bridges within the boundaries of the ShakeMap. To identify these bridges using a prioritization strategy based solely on epicentral distance, it would have been necessary to inspect 1,447 (42%) bridges. To help the Washington State Department of Transportation (WSDOT) rapidly identify damaged bridges, the prioritization procedure has been incorporated within the Pacific Northwest Seismic Network (PNSN) ground-motion processing and notification software.

A Seismic Reliability Assessment of Reinforced Concrete Integral Bridges Subject to Corrosion

2013 ◽  
Vol 569-570 ◽  
pp. 366-373 ◽  
Author(s):  
Mairéad Ní Choine ◽  
Alan O’Connor ◽  
Jamie E. Padgett
Keyword(s):  
Finite Element ◽  
Ground Motion ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Limit State ◽  
Element Model ◽  
Ground Acceleration ◽  
Seismic Reliability ◽  
Bridge Type ◽  
Critical Components

This paper seeks to determine the effect deterioration has on the seismic vulnerability of a 3 span integral concrete bridge. Traditionally it has been common to neglect the effects of deterioration when assessing the seismic vulnerability of bridges. However, since a lot of the bridges currently being assessed for retrofit are approaching the end of their design life, deterioration is often significant. Furthermore, since deterioration affects the main force resisting components of a bridge, it is reasonable to assume that it might affect its performance during an earthquake. For this paper, chloride induced corrosion of the reinforcing steel in the columns and in the deck has been considered. Corrosion is represented by a loss of steel cross section and strength. A 3 dimensional non-linear finite element model is created using the finite element platform Opensees. A full probabilistic analysis is conducted to develop time-dependent fragility curves. These fragility curves give the probability of reaching or exceeding a defined damage limit state, for a given ground motion intensity measure taken as Peak Ground Acceleration (PGA). This analysis accounts for variation in ground motion, material and corrosion parameters when assessing its overall seismic performance as well as the performance of its most critical components. The results of the study show that all components experience an increase in fragility with age, but that the columns are the most sensitive component to aging and dominate the system fragility for this bridge type.

scholarly journals Seismic Fragility Analysis of Institutional Building of Pokhara University

2020 ◽  
Vol 1 (1) ◽  
pp. 31-39
Author(s):  
Narayan Ghimire ◽  
Hemchandra Chaulagain
Keyword(s):  
Numerical Analysis ◽  
Ground Motion ◽  
Structural Damage ◽  
Fragility Curves ◽  
Building Blocks ◽  
Ground Acceleration ◽  
Fragility Function ◽  
2015 Gorkha Earthquake ◽  
Ground Motion Parameter ◽  
Log Normal

Fragility curves are derived from fragility function that indicates the probability of damage of structure due to earthquake as a function of ground motion parameter. It helps to predict the level of structural damage and consequently reduce the seismic risk in specific ground motion. In this scenario, this study is focused on the construction of fragility curve of institutional reinforced concrete (RC) building of Pokhara University. For this, the building of School of Health and Allied Science (SHAS) is considered as a guiding case study. For the numerical analysis, the study building blocks are modelled in finite element-based software. The non-linear static and linear dynamic analyses are employed for numerical analysis. In dynamic analysis, building models are subjected to the synthetic accelerograms of the 2015 Gorkha earthquake. Based on the analyses, the analytical fragility curves are plotted in terms of probability of failure at every 0.1 g interval of peak ground acceleration (PGA) with log normal distribution. Finally, the results are highlighted for different seismic performance level in buildings: slight damage, moderate damage, extensive damage and complete damage for the earthquake of 475 years return period.

scholarly journals Empirical seismic fragility models for Nepalese school buildings

2020 ◽  
Vol 105 (1) ◽  
pp. 339-362 ◽  
Author(s):  
Nicola Giordano ◽  
Flavia De Luca ◽  
Anastasios Sextos ◽  
Fernando Ramirez Cortes ◽  
Carina Fonseca Ferreira ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Structural Characteristics ◽  
Fragility Curves ◽  
School Buildings ◽  
Data Sets ◽  
Loss Assessment ◽  
Building Stock ◽  
Urban Settlements ◽  
Damage Data ◽  
The Impact

AbstractEmpirical vulnerability models are fundamental tools to assess the impact of future earthquakes on urban settlements and communities. Generally, they consist of sets of fragility curves that are derived from georeferenced post-earthquake damage data. Following the 2015 Nepal earthquake sequence, the World Bank, through the Global Program for Safer Schools, conducted a Structural Integrity and Damage Assessment (SIDA) of about 18,000 school buildings in the earthquake-affected area. In this work, the database is utilized to identify the main structural characteristics of the Nepalese school building stock. For the first time, extended SIDA school damage data is processed to derive fragility curves for the main structural typologies. Data sets for each structural typology are used for a Bayesian updating of existing fragilities to obtain regional models for Nepalese schools. These fragility estimates can be adopted to assess potential seismic losses of the school infrastructure in Nepal. Additionally, they can be used for calibrating loss assessment studies in the wider Himalayan region where the structural typologies are similar.

scholarly journals Empirical fragility curves for Italian residential RC buildings

2020 ◽  
Author(s):  
A. Rosti ◽  
C. Del Gaudio ◽  
M. Rota ◽  
P. Ricci ◽  
M. Di Ludovico ◽  
...  
Keyword(s):  
Fragility Curves ◽  
National Level ◽  
Fragility Analysis ◽  
Negative Evidence ◽  
Building Height ◽  
Damage Level ◽  
Depth Analysis ◽  
Damage Data ◽  
Building Characteristics ◽  
Observed Damage

AbstractIn this paper, empirical fragility curves for reinforced concrete buildings are derived, based on post-earthquake damage data collected in the aftermath of earthquakes occurred in Italy in the period 1976–2012. These data, made available through an online platform called Da.D.O., provide information on building position, building characteristics and damage detected on different structural components. A critical review of this huge amount of data is carried out to guarantee the consistency among all the considered databases. Then, an in-depth analysis of the degree of completeness of the survey campaign is made, aiming at the identification of the Municipalities subjected to a partial survey campaign, which are discarded from fragility analysis. At the end of this stage, only the Irpinia 1980 and L’Aquila 2009 databases are considered for further elaborations, as fully complying with these criteria. The resulting database is then integrated with non-inspected buildings sited in less affected areas (assumed undamaged), to account for the negative evidence of damage. The PGA evaluated from the shakemaps of the Italian National Institute of Geophysics and Volcanology (INGV) and a metric based on six damage levels according to EMS-98 are used for fragility analysis. The damage levels are obtained from observed damage collected during post-earthquake inspections through existing conversion rules, considering damage to vertical structures and infills/partitions. The maximum damage level observed on vertical structures and infills/partitions is then associated to the whole building. Fragility curves for two vulnerability classes, C2 and D, further subdivided into three classes of building height, are obtained from those derived for specific structural typologies (identified based on building height and type of design), using their frequency of occurrence at national level as weights.

scholarly journals Fragility Estimation for Global Building Classes Using Analysis of the Cambridge Earthquake Damage Database (CEQID)

2021 ◽  
Author(s):  
Robin Spence ◽  
Sandra Martinez-Cuevas ◽  
Hannah Baker
Keyword(s):  
Fragility Curves ◽  
Resistance Index ◽  
Earthquake Damage ◽  
Ground Acceleration ◽  
Damage Level ◽  
Ground Motion Parameter ◽  
Geographical Regions ◽  
Concrete Building ◽  
Damage Data ◽  
Regional Comparisons

Abstract This paper describes CEQID, a database of earthquake damage and casualty data assembled since the 1980s based on post-earthquake damage surveys conducted by a range of research groups. Following 2017–2019 updates, the database contains damage data for more than five million individual buildings in over 1000 survey locations following 79 severely damaging earthquakes worldwide. The building damage data for five broadly defined masonry and reinforced concrete building classes has been assembled and a uniform set of six damage levels assigned. Using estimated peak ground acceleration (PGA) for each survey location based on USGS Shakemap data, a set of lognormal fragility curves has been developed to estimate the probability of exceedance of each damage level for each class, and separate fragility curves for each of five geographical regions are presented. A revised set of fragility curves has also been prepared in which the bias in the curve resulting from the uncertainty in the ground motion parameter has been removed. The uncertainty in the fragility curves is evaluated and discussed and the curves are compared with those from other studies. A resistance index for each class of building is developed and cross-regional comparisons using this resistance index are presented.

scholarly journals A Technological System for Post-Earthquake Damage Scenarios Based on the Monitoring by Means of an Urban Seismic Network

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7887
Author(s):  
Antonio Costanzo ◽  
Sergio Falcone ◽  
Antonino D’Alessandro ◽  
Giovanni Vitale ◽  
Sonia Giovinazzi ◽  
...  
Keyword(s):  
Ground Motion ◽  
Disaster Response ◽  
Structural Characteristics ◽  
Fragility Curves ◽  
Earthquake Damage ◽  
Technological System ◽  
Real Time Processing ◽  
Damage Level ◽  
Damage Scenarios ◽  
Operational Test

A technological system capable of automatically producing damage scenarios at an urban scale, as soon as an earthquake occurs, can help the decision-makers in planning the first post-disaster response, i.e., to prioritize the field activities for checking damage, making a building safe, and supporting rescue and recovery. This system can be even more useful when it works on densely populated areas, as well as on historic urban centers. In the paper, we propose a processing chain on a GIS platform to generate post-earthquake damage scenarios, which are based: (1) on the near real-time processing of the ground motion, that is recorded in different sites by MEMS accelerometric sensor network in order to take into account the local effects, and (2) the current structural characteristics of the built heritage, that can be managed through an information system from the local public administration authority. In the framework of the EU-funded H2020-ARCH project, the components of the system have been developed for the historic area of Camerino (Italy). Currently, some experimental fragility curves in the scientific literature, which are based on the damage observations after Italian earthquakes, are implemented in the platform. These curves allow relating the acceleration peaks obtained by the recordings of the ground motion with the probability to reach a certain damage level, depending on the structural typology. An operational test of the system was performed with reference to an ML3.3 earthquake that occurred 13 km south of Camerino. Acceleration peaks between 1.3 and 4.5 cm/s2 were recorded by the network, and probabilities lower than 35% for negligible damage (and then about 10% for moderate damage) were calculated for the historical buildings given this low-energy earthquake.

scholarly journals Empirical fragility assessment using conditional GMPE-based ground shaking fields: application to damage data for 2016 Amatrice Earthquake

2020 ◽  
Vol 18 (15) ◽  
pp. 6629-6659
Author(s):  
A. Miano ◽  
F. Jalayer ◽  
G. Forte ◽  
A. Santo
Keyword(s):  
Ground Motion ◽  
Fragility Curves ◽  
Accurate Estimation ◽  
Motion Prediction ◽  
Joint Probability Distribution ◽  
Ground Motion Prediction ◽  
Ground Shaking ◽  
Spatial Correlation Structure ◽  
Explicit Consideration ◽  
Observed Damage

Abstract Recent earthquakes have exposed the vulnerability of existing buildings; this is demonstrated by damage incurred after moderate-to-high magnitude earthquakes. This stresses the need to exploit available data from different sources to develop reliable seismic risk components. As far as it regards empirical fragility assessment, accurate estimation of ground-shaking at the location of buildings of interest is as crucial as the accurate evaluation of observed damage for these buildings. This implies that explicit consideration of the uncertainties in the prediction of ground shaking leads to more robust empirical fragility curves. In such context, the simulation-based methods can be employed to provide fragility estimates that integrate over the space of plausible ground-shaking fields. These ground-shaking fields are generated according to the joint probability distribution of ground-shaking at the location of the buildings of interest considering the spatial correlation structure in the ground motion prediction residuals and updated based on the registered ground shaking data and observed damage. As an alternative to the embedded coefficients in the ground motion prediction equations accounting for subsoil categories, stratigraphic coefficients can be applied directly to the ground motion fields at the engineering bedrock level. Empirical fragility curves obtained using the observed damage in the aftermath of Amatrice Earthquake for residential masonry buildings show that explicit consideration of the uncertainty in the prediction of ground-shaking significantly affects the results.

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