• Structural Engineering and Mechanics
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• v.15 no.3
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• pp.285-297
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• 2003

Complementing recent advances made in the field of structural health monitoring and damage detection, the concept of a wireless sensing network with distributed computational power is proposed. The fundamental building block of the proposed sensing network is a wireless sensing unit capable of acquiring measurement data, interrogating the data and transmitting the data in real time. The computational core of a prototype wireless sensing unit can potentially be utilized for execution of embedded engineering analyses such as damage detection and system identification. To illustrate the computational capabilities of the proposed wireless sensing unit, the fast Fourier transform and auto-regressive time-series modeling are locally executed by the unit. Fast Fourier transforms and auto-regressive models are two important techniques that have been previously used for the identification of damage in structural systems. Their embedment illustrates the computational capabilities of the prototype wireless sensing unit and suggests strong potential for unit installation in automated structural health monitoring systems.

• Structural Engineering and Mechanics
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• v.47 no.4
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• pp.471-493
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• 2013

This paper presents a framework for seismic damage evaluation for Algerian buildings adapted from HAZUS approach (Hazard-United States). Capacity and fragility curves were adapted to fit the Algerian building typologies (Reinforced Concrete structures, Confined or Non-Confined Masonry, etc). For prediction purposes, it aims to estimate the damages and potential losses that may be generated by a given earthquake in a prone area or country. Its efficiency is validated by comparing the estimated and observed damages in Boumerd$\grave{e}$s city, in the aftermath of Boumerd$\grave{e}$s earthquake (Algeria: May $21^{st}$ 2003; $M_w$ = 6.8). For this purpose, observed damages reported for almost 3,700 buildings are compared to the theoretical predictions obtained under two distinct modelling of the seismic hazard. In one hand, the site response spectrum is built according to real accelerometric records obtained during the main shock. In the other hand, the effective Algerian seismic code response spectrum (RPA 99) in use by the time of the earthquake is considered; it required the prior fitting of Boumerd$\grave{e}$s site PGA (Peak Ground Acceleration) provided by Ambraseys' attenuation relationship.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.3
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• pp.171-180
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• 2016

Earthquake event keeps increasing every year, and the recent cases of earthquake hazards invoke the necessity of seismic study in Korea, as geotechnical earthquake hazards, such as strong ground motion, liquefaction and landslides, are a significant threat to structures in industrial hub areas including coastal facilities. In this study, systemized framework of integrated assessment of earthquake-induced geotechnical hazard was established using advanced geospatial database. And a visible simulation of the framework was specifically conducted at two coastal facility areas in Incheon. First, the geospatial-grid information in the 3D domain were constructed with geostatistical interpolation method composed of multiple geospatial coverage mapping and 3D integration of geo-layer construction considering spatial outliers and geotechnical uncertainty. Second, the behavior of site-specific seismic responses were assessed by incorporating the depth to bedrock, mean shear wave velocity of the upper 30 m, and characteristic site period based on the geospatial-grid. Third, the normalized correlations between rock-outcrop accelerations and the maximum accelerations of each grid were determined considering the site-specific seismic response characteristics. Fourth, the potential damage due to liquefaction was estimated by combining the geospatial-grid and accelerations correlation grid based on the simplified liquefaction potential index evaluation method.

• Earthquakes and Structures
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• v.13 no.4
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• pp.365-375
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• 2017

Seismic risk management has two main technical aspects: to recommend the construction of high-performance buildings and other structures using earthquake-resistant designs or evaluate existing ones, and to prepare emergency plans using realistic seismic scenarios. An overview of seismic risk assessment methodologies in Croatia is provided with details regarding the components of the assessment procedures: hazard, vulnerability and exposure. For Croatia, hazard is presented with two maps and it is expressed in terms of the peak horizontal ground acceleration during an earthquake, with the return period of 95 or 475 years. A standard building typology catalogue for Croatia has not been prepared yet, but a database for the fourth largest city in Croatia is currently in its initial stage. Two methods for earthquake vulnerability assessment are applied and compared. The first is a relatively simple and fast analysis of potential seismic vulnerability proposed by Croatian researchers using damage index (DI) as a numerical value indicating the level of structural damage, while the second is the Macroseismic method.

• Earthquakes and Structures
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• v.27 no.3
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• pp.239-250
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• 2024

Traditional immovable cultural assets are significant in terms of societal memory and cultural continuity. Therefore, it is essential to preserve their original qualities without alteration while also assessing their resilience under various influences. This study aims to document the Kırklareli Museum building and conduct a performance analysis for potential earthquake scenarios. To this end, surveys of the structure were conducted, on-site inspections were carried out, and ground and material properties were determined for use in the analysis. The 3D model of the structure was prepared to understand its behavior during earthquakes. The analysis results indicate that there will be no damage to the structure. However, it should be noted that damage could occur in the event of a more severe earthquake than the design earthquake specified by the regulations. This study is significant not only for encompassing the museum structure but also for providing a comprehensive evaluation by determining all material properties.

• Geomechanics and Engineering
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• v.21 no.2
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• pp.179-186
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• 2020

Investigating damage potential of the railway infrastructure requires either large amount of case histories or in-depth numerical analyses, or both for which large amounts of effort and time are necessary to accomplish thoroughly. Rather than performing comprehensive studies for each damage case, in this study we collect and analyze a case history of the high-speed railway system damaged by the 2004 M6.6 Niigata Chuetsu earthquake for the development of the seismic fragility curve. The development processes are: 1) slice the railway system as 200 m segments and assigned damage levels and intensity measures (IMs) to each segment; 2) calculate probability of damage for a given IM; 3) estimate fragility curves using the maximum likelihood estimation regression method. Among IMs considered for fragility curves, spectral acceleration at 3 second period has the most prediction power for the probability of damage occurrence. Also, viaduct-type structure provides less scattered probability data points resulting in the best-fitted fragility curve, but for the tunnel-type structure data are poorly scattered for which fragility curve fitted is not meaningful. For validation purpose fragility curves developed are applied to the 2016 M7.0 Kumamoto earthquake case history by which another high-speed railway system was damaged. The number of actual damaged segments by the 2016 event is 25, and the number of equivalent damaged segments predicted using fragility curve is 22.21. Both numbers are very similar indicating that the developed fragility curve fits well to the Kumamoto region. Comparing with railway fragility curves from HAZUS, we found that HAZUS fragility curves are more conservative.

• Earthquakes and Structures
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• v.18 no.2
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• pp.147-162
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• 2020

This paper presents a novel precast energy dissipation shear wall (PEDSW) structure system that using mild steel dampers as dry connectors at the vertical joints to connect adjacent wall panels. Analytical studies are systematically conducted to investigate the seismic performance of the proposed PEDSW under sequence-type ground motions. During earthquake events, earthquake sequences have the potential to cause severe damage to structures and threaten life safety. To date, the damage probability of engineering structures under earthquake sequence has not been included in structural design codes. In this study, numerical simulations on single-story PEDSW are carried out to validate the feasibility and reliability of using mild steel dampers to connect the precast shear walls. The seismic responses of the PEDSW and cast-in-place shear wall (CIPSW) are comparatively studied based on nonlinear time-history analyses, and the effectiveness of the proposed high-rise PEDSW is demonstrated. Next, the foreshock-mainshock-aftershock type earthquake sequences are constructed, and the seismic response and fragility curves of the PEDSW under single mainshock and earthquake sequences are analyzed and compared. Finally, the fragility analysis of PEDSW structure under earthquake sequences is performed. The influences of scaling factor of the aftershocks (foreshocks) to the mainshocks on the fragility of the PEDSW structure under different damage states are investigated. The numerical results reveal that neglecting the effect of earthquake sequence can lead to underestimated seismic responses and fragilities, which may result in unsafe design schemes of PEDSW structures.

• Geomechanics and Engineering
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• v.33 no.5
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• pp.487-506
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• 2023

Looking from the past to the present, the earthquakes can be said to be type of disaster with most casualties among natural disasters. Soil liquefaction, which occurs under repeated loads such as earthquakes, plays a major role in these casualties. In this study, analytical equation models were developed to predict the probability of occurrence of soil liquefaction. In this context, the parameters effective in liquefaction were determined out of 170 data sets taken from the real field conditions of past earthquakes, using WEKA decision tree. Linear, Exponential, Power and Quadratic models have been developed based on the identified earthquake and ground parameters using Krill Herd algorithm. The Exponential model, among the models including the magnitude of the earthquake, fine grain ratio, effective stress, standard penetration test impact number and maximum ground acceleration parameters, gave the most successful results in predicting the fields with and without the occurrence of liquefaction. This proposed model enables the researchers to predict the liquefaction potential of the soil in advance according to different earthquake scenarios. In this context, measures can be realized in regions with the high potential of liquefaction and these measures can significantly reduce the casualties in the event of a new earthquake.

• Earthquakes and Structures
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• v.10 no.6
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• pp.1315-1330
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• 2016

This study investigates ground motion parameters and their damage potential for building type structures. It focuses on low and mid-rise reinforced concrete buildings that are important portion of the existing building stock under seismic risk in many countries. Correlations of 19 parameters of 466 earthquake records with nonlinear displacement demands of 1056 Single Degree of Freedom (SDOF) systems are investigated. Properties of SDOF systems are established to represent RC building construction practice. The correlation of damage and ground motion characteristics is examined with respect to number of story and site classes. Equations for average nonlinear displacement demands of considered RC buildings are given for some of the ground motion parameters. Velocity related parameters are generally found to have better results than the acceleration, displacement and frequency related ones. Correlation of the parameters may be expected to decrease with increasing intensity of seismic event. Velocity Spectrum Intensity and Peak Ground Velocity have been found to have the highest correlation values for almost all site classes and number of story groups. Common parameter of Peak Ground Acceleration has lower correlation with damage when compared to them and some other parameters like Effective Design Acceleration and Characteristic Intensity.

• Earthquakes and Structures
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• v.12 no.5
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• pp.529-541
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• 2017

According to the definition, progressive collapse could occur due to the initial partial failure of the structural members which by spreading to the adjacent members, could result in partial or overall collapse of the structure. Up to now, most researchers have investigated the progressive collapse due to explosion, fire or impact loads. But new research has shown that the seismic load could also be a factor for initiation of the progressive collapse. In this research, the progressive collapse capacity for the 5 and 15-story steel special moment resisting frames using push-down nonlinear static analysis, and nonlinear dynamic analysis under the gravity loads specified in the GSA Guidelines, were studied. After identifying the critical members, in order to investigate the seismic progressive collapse, the 5-story steel special moment resisting frame was analyzed by the nonlinear time history analysis under the effect of earthquakes with different characteristics. In order to account for the initial damage, one of the critical columns was weakened at the initiation of the earthquake or its Peak Ground Acceleration (PGA). The results of progressive collapse analyses showed that the potential of progressive collapse is considerably dependent upon location of the removed column and the number of stories, also the results of seismic progressive collapse showed that the dynamic response of column removal under the seismic load is completely dependent on earthquake characteristics like Arias intensity, PGA and earthquake frequency contents.