scholarly journals Construction Stage Seismic Vulnerability Evaluation of a Continuous Girder Bridge with the Cast-in-Place Cantilever Construction Method

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Hongxu Li ◽  
Yong Huang ◽  
Endong Guo
Keyword(s):  
Seismic Vulnerability ◽  
Construction Method ◽  
Mode Shapes ◽  
Exceedance Probability ◽  
Loss Ratio ◽  
Construction Stage ◽  
Ground Acceleration ◽  
Continuous Girder Bridge ◽  
The Mean ◽  
Cantilever Construction

To evaluate the vulnerability of bridges at various construction stages under the action of strong earthquakes, the incremental dynamic analysis (IDA) method is applied, and the vulnerabilities of a continuous girder case study bridge with the cast-in-place cantilever construction method, which owns five main construction stages, are evaluated and compared. The results show the following: With the increase in the peak ground acceleration (PGA), the vulnerabilities of bridges at different construction stages all increase. The fragility and vulnerability are mainly determined by the structural mechanical system condition and the mode shapes but not the modal frequency. For the working condition of seismic PGA of 0.4 g, (1) the bridge at the substructure construction stage may only experience slight or moderate damage with the exceedance probability of 8% to 5% and the mean loss ratio being only about 5%; (2) the vulnerabilities of bridges at the middle cantilever construction stage and the long cantilever construction stage are similar, the collapse damage exceedance probability is about 80%, and the mean loss ratio is about 65%; and (3) the vulnerabilities of bridges at the middle span closure construction stage and the bridge completion construction stage are nearly the same, the collapse damage exceedance probability is about 98%, and the mean loss ratio can reach 80%. The research results explore a new method for evaluating the vulnerability of bridges at different construction stages, which can provide suggestions for seismic damage defense and seismic insurance risk evaluation.

Seismic Fragility Analysis of Hill Buildings with Uneven Ground Column Heights

2014 ◽  
Vol 638-640 ◽  
pp. 1848-1853
Author(s):  
Lin Qing Huang ◽  
Li Ping Wang ◽  
Chao Lie Ning
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Slope Angle ◽  
Seismic Fragility ◽  
Exceedance Probability ◽  
Considerable Influence ◽  
Analysis Method ◽  
Ground Acceleration ◽  
Mountainous Regions ◽  
The Hill

The hill buildings sited on slopes have been widely constructed in mountainous regions. In order to estimate the seismic vulnerability of the hill buildings with uneven ground column heights under the effect of potential earthquakes, the exceedance probabilities of the hill buildings sited on different angle slopes in peak ground acceleration (PGA) are calculated and compared by using the incremental dynamic analysis method. The fragility curves show the slope angle has considerable influence on the seismic performance. Specifically, the exceedance probability increases with the increasing of the slope angle at the same performance level.

scholarly journals Seismic Vulnerability Analysis of Multispan Continuous Bridges Subjected to Mainshock-Aftershock Earthquake Sequences

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Yan Liang ◽  
Yukun Cui ◽  
Chao Ren
Keyword(s):  
Seismic Vulnerability ◽  
Estimation Method ◽  
Second Order ◽  
Estimation Methods ◽  
Exceedance Probability ◽  
Damage State ◽  
Ground Acceleration ◽  
Boundary Estimation ◽  
Bridge Model ◽  
Bridge System

A multispan continuous 3D bridge model is established on the basis of OpenSees platform, and 160 mainshock-aftershock (MA) sequences are constructed in accordance with the bridge site to study their influence on the seismic vulnerability of bridges. The seismic vulnerability of bridge piers, bearings, and abutments subjected to MA sequences is investigated. The influence of MA sequences on the seismic vulnerability of the bridge system is also analysed using first- and second-order boundary estimation methods. Results show that the seismic response and exceedance probability of the bridge components and system subjected to MA sequences are significantly increased compared with those under the consideration of mainshock only. The second-order boundary estimation method based on component correlation coefficient can significantly reduce the upper and lower limit widths of the vulnerability curves and improve the accuracy. Under the same peak ground acceleration (PGA) and damage state, the exceedance probability of the bridge system is higher than that of any component in the system. The exceedance probability under different damage states of the bridge components and system increases with the PGA. For any given PGA, the exceedance probability decreases with the increase in severity of damage state.

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 From scenario-based seismic hazard to scenario-based landslide hazard: fast-forwarding to the future via statistical simulations

2021 ◽  
Author(s):  
Luigi Lombardo ◽  
Hakan Tanyas
Keyword(s):  
Ground Motion ◽  
Landslide Susceptibility ◽  
Additive Model ◽  
Landslide Hazard ◽  
Northridge Earthquake ◽  
Ground Acceleration ◽  
Temporal Dimension ◽  
Earthquake Scenario ◽  
The Mean ◽  
Ground Motion Scenarios

AbstractGround motion scenarios exists for most of the seismically active areas around the globe. They essentially correspond to shaking level maps at given earthquake return times which are used as reference for the likely areas under threat from future ground displacements. Being landslides in seismically actively regions closely controlled by the ground motion, one would expect that landslide susceptibility maps should change as the ground motion patterns change in space and time. However, so far, statistically-based landslide susceptibility assessments have primarily been used as time-invariant.In other words, the vast majority of the statistical models does not include the temporal effect of the main trigger in future landslide scenarios. In this work, we present an approach aimed at filling this gap, bridging current practices in the seismological community to those in the geomorphological and statistical ones. More specifically, we select an earthquake-induced landslide inventory corresponding to the 1994 Northridge earthquake and build a Bayesian Generalized Additive Model of the binomial family, featuring common morphometric and thematic covariates as well as the Peak Ground Acceleration generated by the Northridge earthquake. Once each model component has been estimated, we have run 1000 simulations for each of the 217 possible ground motion scenarios for the study area. From each batch of 1000 simulations, we have estimated the mean and 95% Credible Interval to represent the mean susceptibility pattern under a specific earthquake scenario, together with its uncertainty level. Because each earthquake scenario has a specific return time, our simulations allow to incorporate the temporal dimension into any susceptibility model, therefore driving the results toward the definition of landslide hazard. Ultimately, we also share our results in vector format – a .mif file that can be easily converted into a common shapefile –. There, we report the mean (and uncertainty) susceptibility of each 1000 simulation batch for each of the 217 scenarios.

Stationary and Transient Response of Cylindrical Shells Under Random Excitation

1988 ◽  
Vol 110 (2) ◽  
pp. 205-209
Author(s):  
A. V. Singh
Keyword(s):  
Transient Response ◽  
Random Vibration ◽  
Time History ◽  
Wide Band ◽  
Random Excitation ◽  
Mode Shapes ◽  
The Finite Element Method ◽  
History Of ◽  
The Mean ◽  
Random Vibration Analysis

This paper presents the random vibration analysis of a simply supported cylindrical shell under a ring load which is uniform around the circumference. The time history of the excitation is assumed to be a stationary wide-band random process. The finite element method and the condition of symmetry along the length of the cylinder are used to calculate the natural frequencies and associated mode shapes. Maximum values of the mean square displacements and velocities occur at the point of application of the load. It is seen that the transient response of the shell under wide band stationary excitation is nonstationary in the initial stages and approaches the stationary solution for large value of time.

scholarly journals Seismic hazard of Northern Eurasia

1999 ◽  
Vol 42 (6) ◽  
Author(s):  
V. I. Ulomov ◽  
. The GSHAP Region Working Group
Keyword(s):  
Seismic Hazard ◽  
Strong Motion ◽  
Seismic Hazard Assessment ◽  
Exceedance Probability ◽  
Hazard Mapping ◽  
Northern Eurasia ◽  
Ground Acceleration ◽  
Border Regions ◽  
Seismic Catalogue ◽  
Close Cooperation

The GSHAP Regional Centre in Moscow, UIPE, has coordinated the seismic hazard mapping for the whole territory of the former U.S.S.R. and border regions. A five-year program was conducted to assemble for the whole area, subdivided in five overlapping blocks, the unified seismic catalogue with uniform magnitude, the strong motion databank and the seismic zones model (lineament-domain-source), which form the basis of a newly developed deterministic-probabilistic computation of seismic hazard assessment. The work was conducted in close cooperation with border regions and GSHAP regional centers. The hazard was originally computed in terms of expected MSK intensity and then transformed into expected peak ground acceleration with 10% exceedance probability in 50 years.

Characterization of Ground Response and Liquefaction for Kathmandu City Based on 2015 Earthquake Using Total Stress and Effective Stress Approach

2020 ◽  
Vol 11 (2) ◽  
pp. 1-25
Author(s):  
Shiv Shankar Kumar ◽  
Pradeep Acharya ◽  
Pradeep Kumar Dammala ◽  
Murali Krishna Adapa
Keyword(s):  
Peak Ground Acceleration ◽  
Seismic Vulnerability ◽  
Ground Motions ◽  
Total Stress ◽  
Ground Response ◽  
Ground Acceleration ◽  
Liquefaction Potential ◽  
Potential Index ◽  
Semi Empirical

This chapter presents the seismic vulnerability of Kathmandu City (Nepal), based on Nepal 2015 earthquake, in terms of the ground response and liquefaction potential. The spatially well-distributed 10-boreholes and ground motions of Mw 7.8 Nepal 2015 earthquake recorded at five different stations were adopted for the analysis. The range of peak ground acceleration and peak spectral acceleration were in the order of 0.21g-0.42g and 0.74g-1.50g, respectively. Liquefaction potential of the sites were computed using both semi-empirical approach and liquefaction potential index (LPI). LPI shows that the 6 sites out of 10 sites are at high risk of liquefaction.

scholarly journals Development of a Large Flood Regionalisation Model Considering Spatial Dependence—Application to Ungauged Catchments in Australia

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 677 ◽  
Author(s):  
Khaled Haddad ◽  
Ataur Rahman
Keyword(s):  
Spatial Dependence ◽  
Regional Analysis ◽  
Hydraulic Structures ◽  
Exceedance Probability ◽  
Positive Bias ◽  
Ungauged Catchments ◽  
The Mean ◽  
Relative Errors ◽  
A Site ◽  
Large Floods

Estimation of large floods is imperative in planning and designing large hydraulic structures. Due to the limited availability of observed flood data, estimating the frequencies of large floods requires significant extrapolation beyond the available data. This paper presents the development of a large flood regionalisation model (LFRM) based on observed flood data. The LFRM assumes that the maximum observed flood data over a large number of sites in a region can be pooled together by accounting for the at-site variations in the mean and coefficient of variation. The LFRM is enhanced by adding a spatial dependence model, which accounts for the net information available for regional analysis. It was found that the LFRM, which accounts for spatial dependence and that pools 1 or 3 maxima from a site, was able to estimate the 1 in 1000 annual exceedance probability flood quantile with consistency, showing a positive bias on average (5–7%) and modest median relative errors (30–33%).

scholarly journals Seismic Vulnerability Assessment and Mapping of Gyeongju, South Korea Using Frequency Ratio, Decision Tree, and Random Forest

2020 ◽  
Vol 12 (18) ◽  
pp. 7787 ◽  
Author(s):  
Jihye Han ◽  
Jinsoo Kim ◽  
Soyoung Park ◽  
Sanghun Son ◽  
Minji Ryu
Keyword(s):  
Random Forest ◽  
Decision Tree ◽  
South Korea ◽  
Vulnerability Assessment ◽  
Seismic Data ◽  
Frequency Ratio ◽  
Seismic Vulnerability ◽  
Success Rates ◽  
Ground Acceleration ◽  
Seismic Vulnerability Assessment

The main purpose of this study was to compare the prediction accuracies of various seismic vulnerability assessment and mapping methods. We applied the frequency ratio (FR), decision tree (DT), and random forest (RF) methods to seismic data for Gyeongju, South Korea. A magnitude 5.8 earthquake occurred in Gyeongju on 12 September 2016. Buildings damaged during the earthquake were used as dependent variables, and 18 sub-indicators related to seismic vulnerability were used as independent variables. Seismic data were used to construct a model for each method, and the models’ results and prediction accuracies were validated using receiver operating characteristic (ROC) curves. The success rates of the FR, DT, and RF models were 0.661, 0.899, and 1.000, and their prediction rates were 0.655, 0.851, and 0.949, respectively. The importance of each indicator was determined, and the peak ground acceleration (PGA) and distance to epicenter were found to have the greatest impact on seismic vulnerability in the DT and RF models. The constructed models were applied to all buildings in Gyeongju to derive prediction values, which were then normalized to between 0 and 1, and then divided into five classes at equal intervals to create seismic vulnerability maps. An analysis of the class distribution of building damage in each of the 23 administrative districts showed that district 15 (Wolseong) was the most vulnerable area and districts 2 (Gangdong), 18 (Yangbuk), and 23 (Yangnam) were the safest areas.

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