• Earthquakes and Structures
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• v.4 no.3
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• pp.299-324
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• 2013

The current research focuses on the seismic vulnerability assessment of typical Southern Europe buildings, based on processing of a large set of observational damage data. The presented study constitutes a sequel of a previous research. The damage statistics have been enriched and a wider damage database (178578 buildings) is created compared to the one of the first presented paper (73468 buildings) with Damage Probability Matrices (DPMs) after the elaboration of the results from post-earthquake surveys carried out in the area struck by the 7-9-1999 near field Athens earthquake. The dataset comprises buildings which developed damage in several degree, type and extent. Two different parameters are estimated for the description of the seismic demand. After the classification of damaged buildings into structural types they are further categorized according to the level of damage and macroseismic intensity. The relative and the cumulative frequencies of the different damage states, for each structural type and each intensity level, are computed and presented, in terms of damage ratio. Damage Probability Matrices (DPMs) are obtained for typical structural types and they are compared to existing matrices derived from regions with similar building stock and soil conditions. A procedure is presented for the classification of those buildings which initially could not be discriminated into structural types due to restricted information and hence they had been disregarded. New proportional DPMs are developed and a correlation analysis is fulfilled with the existing vulnerability relations.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.7_spc
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• pp.527-536
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• 2016

This paper investigates seismic damage potential of recent September 12 M5.8 Gyeongju earthquake from diverse earthquake engineering perspectives using the accelerograms recorded at three stations near the epicenter. In time domain, strong motion durations are evaluated based on the accelerograms and compared with statistical averages of the ground motions with similar magnitude, epicentral distance and soil conditions, while Fourier analysis using FFT is performed to identify damaging frequency contents contained in the earthquake. Effective peak ground accelerations are evaluated from the calculated response spectra and compared with apparent peak ground accelerations and the design spectrum in KBC 2016. All these results are used to consistently explain the reason why most of seismic damage in the earthquake was concentrated on low-rise stiff buildings but not quite significant. In order to comparatively appraise the damage potential, the constant ductility spectrum constructed from the Gyeongju earthquake is compared with that of the well-known 1940 El Centro earthquake. Deconvolution analysis by using one accelerogram speculated to be recorded at a stiff soil site is also performed to estimate the soil profile conforming to the response spectrum characteristics. Finally, response history analysis for 39- and 61-story tall buildings is performed as a case study to explain significant building vibration felt on the upper floors of some tall buildings in Busan area during the Gyeongju earthquake. Seismic design and retrofit implications of M5.8 Gyeongju earthquake are summarized for further research efforts and improvements of relevant practice.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.06a
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• pp.65-81
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• 2003

During the last few decades in Korea, the development of hillside or mountain areas has rapidly increased for infrastructure construction such as railroads, highways and housing. Many landslides have occurred during these constructions. Also, the amount and scale of damage caused by landslides have increased every year. In the case of Far East Asia including Korea, the damage of landslides is consequently reported during the wet season. In this paper, the effect of stabilizing piles on slope stability is checked and the behavior of slope soil and piles are observed throughout the year by field measurements in the large-scale cut slopes. In particular a large-scale cut slope situated on the construction site for the express highway in Donghae, Korea. First of all, The behavior of the slope soil was measured by inclinometers during slope modification. Landslides occurred in this area due to the soil cutting for slope modification. The horizontal deformations of slope soil gradually increased and rapidly decreased at depth of sliding surface indicating that the depth of sliding surface below the ground surface can be predicted. On the basis of being able to predict the depth of the sliding surface, stabilizing piles were designed and constructed in this slope. To ensure the stability of the reinforced slope using stabilizing piles, an instrumentation system was installed. The maximum deflection of piles is measured at the pile head and it is noted that the piles deform like deflection on a cantilever beam. The maximum bending stress of piles is measured at the soil layer. The pile above the soil layer is subjected to lateral earth pressure due to driving force of the slope, while pile below soil layer is subjected to subgrade reaction against pile deflection. As a result of research, the effect and applicability of stabilizing piles in large-scale cut slopes could be confirmed sufficiently.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.5
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• pp.515-524
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• 2016

Damage such as landslides has been caused by natural phenomenon like a heavy rain. As appropriate countermeasures, rather than analysing the cause of the landslide, we used methods of check dam installation and maintenance mountain basin. A check dam is a small, sometimes temporary, dam constructed across a swale, drainage ditch, or waterway to counteract erosion by reducing water flow velocity. In this study, we analysed the adequacy of check dam built to prevent further damage after landslides through GIS and examined the sediment erosion in the existing check dams for an ideal location of check dam, considering the accessibility and size. As a result of reviewing soil loss in the study watershed according to RUSLE(Revised Universal Soil Loss Equation), the basin I had about 2% soil loss reduction, the basin II showed less than 1 % soul loss reduction, and basin III showed the reducing effect of 5 % soil erosion.

• Geomechanics and Engineering
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• v.2 no.1
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• pp.1-18
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• 2010

The analysis of structure response and design of buried structures subjected to dynamic destructive loads have been receiving increasing interest due to recent severe damage caused by strong earthquakes and terrorist attacks. For a comprehensive design of buried structures subjected to blast loads to be conducted, the whole system behaviour including simulation of the explosion, propagation of shock waves through the soil medium, the interaction of the soil with the buried structure and the structure response needs to be simulated in a single model. Such a model will enable more realistic simulation of the fundamental physical behaviour. This paper presents a complete model simulating the whole system using the finite element package ABAQUS/Explicit. The Arbitrary Lagrange Euler Coupling formulation is used to model the explosive charge and the soil region near the explosion to eliminate the distortion of the mesh under high deformation, while the conventional finite element method is used to model the rest of the system. The elasto-plastic Drucker-Prager Cap model is used to model the soil behaviour. The explosion process is simulated using the Jones-Wilkens-Lee equation of state. The Concrete Damage Plasticity model is used to simulate the behaviour of concrete with the reinforcement considered as an elasto-plastic material. The contact interface between soil and structure is simulated using the general Mohr-Coulomb friction concept, which allows for sliding, separation and rebound between the buried structure surface and the surrounding soil. The behaviour of the whole system is evaluated using a numerical example which shows that the proposed model is capable of producing a realistic simulation of the physical system behaviour in a smooth numerical process.

• Journal of the Korea Fashion and Costume Design Association
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• v.21 no.1
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• pp.181-189
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• 2019

The washability, redeposition, fill power, and fabric damage of wet cleaning and dry cleaning solvents were measured to identify the optimal type of washing that would increase washability while maintaining dimensional stability. The soiled fabric is a polyester cotton blend and the types of soil were wine, blood, make-up and sebum with carbon black. Petroleum and silicone solvents were used in dry cleaning. Results from this study are as follows. First, detergency is significantly influenced by the type of washing and type of soil. Wet cleaning is superior to dry cleaning. Wet cleaning shows a strong washing performance against hydrophilic soils, whereas, dry cleaning is stronger against hydrophobic soils. Second, redeposition is significantly affected by the type of washing, fabrics, and soils. Redeposition occurred little on cotton during wet cleaning, but showed a high rate for nylon. However, when the two types of fabric were dry cleaned, redeposition occurred on both types. Third, the fill power of duck-down is very affected by the type of washing. Resilience is the best in wet cleaning; and in dry cleaning, petroleum solvents showed a higher resilience when as compared to silicone solvents. Last, the level of fabric damage to cotton fabrics is highly influenced by the type of washing. Wet cleaning damages cotton fabrics significantly more than dry cleaning. For dry cleaning, petroleum solvents damage these fabrics slightly more than silicone solvents. In conclusion, the type of soil must initially be identified to determine the optimal type of washing. Special caution is required when textiles with particulate soil and nylon are washed. When considering the resilience of duck-down clothing, wet cleaning is more appropriate than dry cleaning. Dry cleaning, especially when using silicone-based solvents, is more suitable than wet cleaning for maintaining the shape of clothing.

• Computers and Concrete
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• v.29 no.5
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• pp.279-283
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• 2022

The seismic analytic collapse fragility of soil nail wall structures with a shotcrete concrete covering is investigated in this paper. The finite element modeling process has been well described. The fragility function evaluates the link between ground motion intensities and the likelihood of reaching a specific level of damage. The soil nail wall has been subjected to incremental dynamic analysis (IDA) from medium to strong ground vibrations. The nonlinear dynamic analysis of the soil nail wall uses a set of 20 earthquake ground motions with varying PGAs. PGD is utilized as an intensity measure, the numerical findings demonstrate that the soil nailing wall reaction is particularly sensitive to earthquake intensity measure (IM).

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.454-461
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• 2001

Dynamic responses of a multi-span simply supported bridge are examined under seismic excitations considering damage of bearings. An idealized mechanical model which can consider components such as pounding, friction at the supports, abutment-soil interaction, rotational and translational motions of foundations, and the nonlinear pier motions, is developed to analyze the effects due to damage of bearings. It is assumed that the bearing's response after failure can be expressed with a sliding model with a friction coefficient between the superstructure and the pier top. It is found that the global seismic behaviors are significantly influenced by the damage of bearings and the damage of bearings may lead to unseating failure at unpredicted supports. Therefore, It can be concluded that detailed seismic response analyses of bridge systems considering damage of bearings is required for the purpose of the seismic safety evaluation.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.686-691
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• 2009

Damage due to frost action in pavement structure system is creating either frost heave or stiffness-weakening of subgrade soil follow melting. The formation of ice lenses requires a frost-susceptible soil, freezing temperatures, and continuous water supply. Eliminating one of these conditions suffices to significantly reduce the intensity of frost action. It is important to know characteristics of subgrade soil in frost susceptibility or decide degree of freezing permission. Also, study on the stiffness variation of subgrade soil during freezing and thawing cycle is very important. In this study, Impact resonance test for subgrade soil at freezing and thawing confirms that is applied for.

• Geomechanics and Engineering
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• v.36 no.3
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• pp.295-301
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• 2024

Understanding the post-liquefaction shear behavior is crucial for predicting and assessing the damage, such as lateral flow, caused by liquefaction. Most studies have focused on the behavior until liquefaction occurs. In this study, we performed undrained multi-stage tests on clean sand, sand-silt mixtures, and silty soils to investigate post-liquefaction shear strain based on soil compressibility. The results confirmed that it is necessary to consider the soil compressibility and the shape of soil particles to understand the post-liquefaction shear strain characteristics. Based on this, an index reflecting soil compressibility and particle shape was derived, and the results showed a high correlation with post-liquefaction small resistance characteristic regardless of soil type and fine particle content.