Seismic fragility models of a bridge system based on copula method

2021 ◽  
pp. 875529302110525
Author(s):  
Libo Chen ◽  
Caigui Huang ◽  
Haiqiang Chen ◽  
Zhenfeng Zheng
Keyword(s):  
Seismic Performance ◽  
Marginal Distribution ◽  
Fragility Curves ◽  
Distribution Functions ◽  
System Level ◽  
Likelihood Method ◽  
Seismic Fragility ◽  
Distribution Model ◽  
Copula Models ◽  
Bridge System

Seismic fragility assessment widely uses a probabilistic measure for assessing the seismic performance of structural components or systems. This article proposes a copula-based seismic fragility (CBSF) method to derive the system-level damage probabilities of reinforced concrete bridges and to consider the correlation among seismic demands of components. First, the marginal distribution functions of the random variables are calibrated, and three Archimedean copula models are considered. Subsequently, the relevant parameters of the copula models are estimated using the semi-parametric maximum likelihood method. Next, the damage probabilities of a bridge system are calculated based on the joint distribution model with the most suitable copula model and the calibrated marginal distribution functions. Finally, the CBSF method is used to estimate the damage probability of a simply supported box girder bridge. The performance of the CBSF method is validated by a comparison of fragility curves obtained using the CBSF method and the probabilistic seismic demand analysis (PSDA) method. The comparative results demonstrate that the fragility curves obtained by the CBSF method are better than those obtained using the PSDA method. The proposed CBSF model can serve as a tool for assessing the seismic performance of structures and estimating the economic loss of existing bridge systems.

Seismic fragility assessment of multi-span concrete highway bridges in British Columbia considering soil–structure interaction

2021 ◽  
Vol 48 (1) ◽  
pp. 39-51 ◽  
Author(s):  
A.H.M. Muntasir Billah ◽  
M. Shahria Alam
Keyword(s):  
British Columbia ◽  
Soil Structure ◽  
Seismic Vulnerability ◽  
Structural Characteristics ◽  
Fragility Curves ◽  
Highway Bridges ◽  
System Level ◽  
Soil Structure Interaction ◽  
Seismic Fragility ◽  
Structure Interaction

Fragility curve is an effective tool for identifying the potential seismic risk and consequences during and after an earthquake. Recent seismic events have shown that bridges are highly sensitive and vulnerable during earthquakes. There has been limited research to evaluate the seismic vulnerability of the existing bridges in British Columbia (BC), which could help in the decision-making process for seismic upgrade. This study focuses on developing seismic fragility curves for typical multi-span continuous concrete girder bridges in BC. Ground motions compatible with the seismic hazard were used as input excitations for vulnerability assessment. Uncertainties in material and geometric properties were considered to represent the bridges with similar structural characteristics and construction period. The fragility of the bridge is largely attributable to the fragilities of the columns, and to a lesser extent, the abutment and bearing components. The results of this study show that, although not very significant, the soil–structure interaction has some effect on the component fragility where this effect is not very significant at the bridge system level.

scholarly journals Fragility-Based Improvement of System Seismic Performance for Long-Span Suspension Bridges

2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Guanya Lu ◽  
Kehai Wang ◽  
Wenhua Qiu
Keyword(s):  
Seismic Performance ◽  
Fragility Curves ◽  
Suspension Bridge ◽  
System Level ◽  
Suspension Bridges ◽  
Fragility Function ◽  
Long Span ◽  
Damage Indices ◽  
Composite Damage ◽  
Demand Models

In this study, a procedure is developed to evaluate and improve the seismic performance of long-span suspension bridges based on the performance objectives under the fragility function framework. A common type of suspension bridge in China was utilized in the proposed procedure, considering its approach structures according to earthquake damage experience and fortification criteria. Component-level fragility curves were derived by probabilistic seismic demand models (PSDMs) using a set of nonlinear time-history analyses that incorporated the related uncertainties such as earthquake motions and structural properties. In addition, one step that was covered was to pinpoint the capacity limit states of critical components including bearings, pylons, and columns. The stepwise improved seismic designs were proposed in terms of the component fragility results of the as-built design. Results of the comparison of improved designs showed that the retrofit measure of the suspension span should be selected based on two attributes, i.e., displacement and force, and the restraint system of the approach bridges was a key factor affecting the reasonable damage sequence. Necessarily, from the comparison of different system vulnerability models, the mean values of earthquake intensity of system-level fragility function developed by the composite damage state indices were used to assess the overall seismic performance of the suspension bridge. The results showed that compared to the absolutely serial and serial-parallel assumptions, the defined composite damage indices incorporating the thought of component classification and structural relative importance between the main bridge and approach structures were necessary and were able to derive a good indicator of seismic performance assessment, hence validating the point that the different damage states were dominated by the seismic demands of different structures for the retrofitted bridges.

Seismic Fragility of Suspended Ceiling Systems

2007 ◽  
Vol 23 (1) ◽  
pp. 21-40 ◽  
Author(s):  
Hiram Badillo-Almaraz ◽  
Andrew S. Whittaker ◽  
Andrei M. Reinhorn
Keyword(s):  
Seismic Performance ◽  
Dynamic Testing ◽  
Fragility Curves ◽  
Full Scale ◽  
Seismic Fragility ◽  
Limit States ◽  
Performance Based Assessment ◽  
Damage States

Full-scale dynamic testing of suspended ceiling systems was performed to obtain fragility data suitable for performance-based assessment and design. On the basis of the fragility data derived from testing, (1) the use of retainer clips improves the performance of ceiling systems in terms of loss of tiles, (2) including recycled cross tees in the suspension grid increases the vulnerability of the ceiling systems, (3) undersized (poorly fitting) tiles are substantially more vulnerable than properly fitted tiles, and (4) the use of compression posts improves the seismic performance of ceiling systems for the limit states of minor and moderate damage. Fragility curves are provided for four damage states.

scholarly journals TRIPLE PROBABILITY DENSITY DISTRIBUTION MODEL IN THE TASK OF AVIATION RISK ASSESSMENT

Aviation ◽  
2020 ◽  
Vol 24 (2) ◽  
pp. 57-65
Author(s):  
Ivan Ostroumov ◽  
Karen Marais ◽  
Nataliia Kuzmenko ◽  
Nicoletta Fala
Keyword(s):  
Risk Assessment ◽  
Density Distribution ◽  
Probability Density ◽  
Error Distribution ◽  
Distribution Functions ◽  
Likelihood Method ◽  
Distribution Model ◽  
Probability Density Distribution ◽  
Generalized Error Distribution ◽  
Aviation Risk

The probability of an airplane deviation from pre-planned trajectory is a core of aviation safety analysis. We propose to use a mixture of three probability density distribution functions it the task of aviation risk assessment. Proposed model takes into account the effect of navigation system error, flight technical error, and occurrence of rare events. Univariate Generalized Error Distribution is used as a basic component of distribution functions, that configures the error distribution model from the normal error distribution to double exponential distribution function. Statistical fitting of training sample by proposed Triple Univariate Generalized Error Distribution (TUGED) is supported by Maximum Likelihood Method. Optimal set of parameters is estimated by sequential approximation method with defined level of accuracy. The developed density model has been used in risk assessment of airplane lateral deviation from runway centreline during take-off and landing phases of flight. The efficiency of the developed model is approved by Chi-square, Akaike’s, and Bayes information criteria. The results of TUGED fitting indicate better performance in comparison with double probability density distribution model. The risk of airplane veering off the runway is considered as the probability of a rare event occurrence and is estimated as an area under the TUGED.

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 Analytical Seismic Fragility Curves for Reinforced Concrete Wall pier using Shape Memory Alloys considering maximum drift

2019 ◽  
Vol 258 ◽  
pp. 04001 ◽  
Author(s):  
Nursafarina Ahmad ◽  
Azmi Ibrahim ◽  
Shahria Alam
Keyword(s):  
Reinforced Concrete ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Seismic Performance ◽  
Fragility Curves ◽  
Plastic Hinge ◽  
Bridge Pier ◽  
Seismic Fragility ◽  
Demand Model ◽  
Promising Alternative

Fragility curves express the seismic vulnerability of bridge piers for different damage states at various earthquake intensities. A fragility curve typically gives a physical understanding of repair costs and functionally levels of a bridge pier. Shape memory alloys (SMAs) provide a promising alternative material in reducing the failure probability of a bridge pier. This study develops a family of seismic fragility curves for reinforced concrete (RC) wall piers reinforced with three different types of SMA rebar in plastic hinge regions. An incremental dynamic analysis (IDA) using a total of 20 earthquake ground motions was performed on a SMA-RC wall pier to evaluate its seismic performance. The maximum drift recorded for each ground motion was taken as the seismic performance demand parameter of interest in this study. The probabilistic seismic demand model (PSDM) was used to generate fragility curves for each RC-SMA wall pier. The results show that the different mechanical properties and type of SMAs affect the performance of RC-SMA wall pier.

scholarly journals An approach to derive seismic fragility curves

2021 ◽  
Vol 1026 (1) ◽  
pp. 012007
Author(s):  
V J Vedhanayaghi ◽  
M Manoharan ◽  
J Jasper Daniel ◽  
S Premkumar ◽  
S ArunBharathi
Keyword(s):  
Fragility Curves ◽  
Seismic Fragility

scholarly journals Comparison of Weibull Estimation Methods for Diverse Winds

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Ferhat Bingöl
Keyword(s):  
Wind Farm ◽  
Study Data ◽  
Distribution Functions ◽  
Likelihood Method ◽  
Estimation Methods ◽  
Weibull Function ◽  
Wind Speeds ◽  
Low Wind Speed ◽  
Low Wind Speeds ◽  
Wind Distribution

Wind farm siting relies on in situ measurements and statistical analysis of the wind distribution. The current statistical methods include distribution functions. The one that is known to provide the best fit to the nature of the wind is the Weibull distribution function. It is relatively straightforward to parameterize wind resources with the Weibull function if the distribution fits what the function represents but the estimation process gets complicated if the distribution of the wind is diverse in terms of speed and direction. In this study, data from a 101 m meteorological mast were used to test several estimation methods. The available data display seasonal variations, with low wind speeds in different seasons and effects of a moderately complex surrounding. The results show that the maximum likelihood method is much more successful than industry standard WAsP method when the diverse winds with high percentile of low wind speed occur.

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