• Earthquakes and Structures
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• v.22 no.6
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• pp.609-623
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• 2022

To study the empirical seismic fragility of a reinforced concrete girder bridge, based on the theory of numerical analysis and probability modelling, a regression fragility method of a rapid fragility prediction model (Gaussian first-order regression probability model) considering empirical seismic damage is proposed. A total of 1,069 reinforced concrete girder bridges of 22 highways were used to verify the model, and the vulnerability function, plane, surface and curve model of reinforced concrete girder bridges (simple supported girder bridges and continuous girder bridges) considering the number of samples in multiple intensity regions were established. The new empirical seismic damage probability matrix and curve models of observation frequency and damage exceeding probability are developed in multiple intensity regions. A comparative vulnerability analysis between simple supported girder bridges and continuous girder bridges is provided. Depending on the theory of the regional mean seismic damage index matrix model, the empirical seismic damage prediction probability matrix is embedded in the multidimensional mean seismic damage index matrix model, and the regional rapid prediction matrix and curve of reinforced concrete girder bridges, simple supported girder bridges and continuous girder bridges in multiple intensity regions based on mean seismic damage index parameters are developed. The established multidimensional group bridge vulnerability model can be used to quantify and predict the fragility of bridges in multiple intensity regions and the fragility assessment of regional group reinforced concrete girder bridges in the future.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.366-373
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• 2006

In order to reduce the secondary earthquake disaster resulting from the damage of gas facilities it is indispensable to establish an early response system on the basis of damage prediction. In this study the procedure of damage prediction for gas facilities is proposed and applied to the gas supply model area. Model area is divided into several little blocks. The soil condition and the characteristics of facilities were investigated at each block. Using fragility curves of facilities the damage level was analyzed under various seismicities. It is confirmed that the exposure gas pipe line in several blocks is damaged seriously by the collapse of building structures.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1206-1208
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• 2003

The extraction of earthquake damage from remote sensed imagery requires high spatial resolution and temporal effectiveness of acquisition of imagery. The analog photographs and visual interpretation were taken traditionally. Now it is possible to acquire damage information from many commercial high resolution RS satellites. The key techniques are processing velocity and precision. The authors developed the automatic / semiautomatic image process techniques including feature enhancement, and classification, designed the emergency Earthquake Damage and Losses Evaluate System based on Remote Sensing (RSEDLES). The paper introduced the functions of RSEDLES as well as its application to the earthquakes occurred recently.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.253-254
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• 2015

Currently, according to the climate change, the damages due to the hurricane is more increased than before. In this respect, several countries have been conducted the studies regarding the damage prediction model of buildings to minimize the damages from natural disaster. As hurricane is the complex disaster including a strong wind and heavy rain, to predict the damage of hurricane, various factors has to be considered. However, mostly research has been conducted to consider only hurricane properties. Therefore, the objective of this study is to develop the regression model for predicting damages of buildings considering geography, socio-economy, construction environment and hurricane information. In the future, this study can be utilized to developing damage prediction model for building from hurricane in South Korea.

• Journal of the Korea Safety Management & Science
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• v.26 no.3
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• pp.59-70
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• 2024

This study aims to estimate the scope of damage impact with a real-life explosion case and a damage prediction program (ALOHA) and suggest measures to reduce risk by comparing and analyzing the results using a Probit model. After applying it to the ALOHA program, the toxicity, overpressure, and radiant heat damage of 5 tons of storage scopes between 66 to 413 meters, and the real-life case also demonstrated that most of the damage took place within 300 meters of the LPG gas station. In the Probit analysis, the damages due to radiant heat were estimated as first-degree burns (13-50%), while structural damage (0-75%) and glass window breakage (94-100%) were expected from overpressure, depending on the storage volume. After comparing the real-life case and the damage prediction program, this study concluded that the ALOHA program could be used as the scope of damage impacts is nearly the same as the actual case; it also concluded that the analysis using the Probit model could reduce risks by applying calculated results and predicting the probability of human casualties and structural damages.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.6
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• pp.64-73
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• 2004

A fatigue damage accumulation model based on the continuum damage mechanics theory was developed where modulus decay ratios in tension and shear were used as indicators for damage variables D. In the model, the damage variables are considered to be second-order tensors. Then, the maximum principal damage variable, $D^*$ is introduced. According to the similarity to the principal stress, $D^*$ is obtained as the maximum eigen value of damage tensor [D]. Under proportional tension and torsion loadings, fatigue lives were satisfactorily predicted at any combined stress ratios using the present model in which the Fatigue characteristics only under uniaxial tension and pure torsion loadings were needed. Fatigue life prediction under uniaxial tension and pure torsion loadings, was performed based on the damage mechanics using boundary element method.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.6
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• pp.63-73
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• 2010

This study is to develop a downstream flood damage prediction model for efficient confrontation in case of extreme and flash flood by future probable small agricultural dam break situation. For a Changri reservoir (0.419 million $m^3$) located in Yongin city of Gyeonggi province, a dam break scenario was prepared. With the probable maximum flood (PMF) condition calculated from the probable maximum precipitation (PMP), the flood condition by dam break was generated by using the HEC-HMS (Hydrologic Engineering Center - Hydrologic Modeling System) model. The flood propagation to the 1.12 km section of Hwagok downstream was simulated using HEC-RAS (Hydrologic Engineering Center - River Analysis System) model. The flood damaged areas were generated by overtopping from the levees and the boundaries were extracted for flood damage prediction, and the degree of flood damage was evaluated using IDEM (Inundation Damage Estimation Method) by modifying MD-FDA (Multi-Dimensional Flood Damage Analysis) and regression analysis simple method. The result of flood analysis by dam-break was predicted to occurred flood depth of 0.4m in interior floodplain by overtopping under PMF scenario, and maximum flood depth was predicted up to 1.1 m. Moreover, for the downstream of the Changri reservoir, the total amount of the maximum flood damage by dam-break was calculated nearly 1.2 billion won by IDEM.

• Journal of Industrial Technology
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• v.18
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• pp.187-193
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• 1998

In this study, about the fatigue life of welded structure material under fluctuation loading, the prediction life which is produced by using the Histogram Recorder System was compared with the experimental life which is produced by the RMC model which is imported by conception of equivalent stress. In this result, this is represented few difference by comparing prediction life which is produced by damage analysis depended on Miner's rule, by using the Histogram Recorder System, with experimental life which is produced by the RMC load model which is imported by conception of equivalent of stress, therefore fatigue life is easily predicted by using Histogram Recorder System, and result of prediction has equivalent accuracy with other method which is more complex than the Histogram Recorder System. Besides the damage which is produced by stress which is high thirty percentage rank in the stress range of damage inducing, is nearly equal to the damage which is induced the rest of seventy percentage, there fore we can see that damage accumulation which is induced few time overload which is effected welded structure material is great.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.2
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• pp.123-129
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• 2012

It was previously suggested the design sensitivity analysis based on transmissibility function to identify the most sensitive response location over a small design modification. On the other hand, energy isoclines were used to predict the fatigue damage with acceleration response only. Both of previous studies commonly tackle the engineering problem using the acceleration response alone such that it may be possible to investigate the relationship between sensitivity analysis and accumulated fatigue damage. In this paper, it is suggested the novel method of vibration fatigue prediction using design sensitivity analysis to enhance the accuracy of predicted accumulated fatigue. Uni-axial vibration testing is performed with a simple notched specimen and the prediction of fatigue damage is conducted using accelerations measured at different locations. It can be concluded that the accuracy of predicted fatigue damage is proportional to the sensitivity index of the responsible location.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.352-361
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• 2003

A fatigue damage accumulation model based on the continuum damage mechanics theory was develope(1 where modules decay ratios in tension and shear on used as indicators for damage variables D . In the model, the damage variables are considered to be second-order tensors. Then the maximum principal damage variable, $D^*$ is introduced According to the similarity to the Principal stress, $D^*$ is obtained as the maximum eigen value of damage tensor [D']. Under proportional tension and torsion loadings, fatigue lives were satisfactorily predicted at any combined stress ratios using the present model in which the fatigue characteristics only under uniaxial tension and pure torsion loadings on needed. Fatigue life prediction under uniaxial tension and pure torsion loadings, was performed based on the damage mechanics using boundary element method.