• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.8 no.3
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• pp.29-35
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• 2012

Geothermal heat pump system has been spotlighted as an efficient building energy system, because it has great potentials for reducing energy in building air conditioning and reducing $CO_2$ emissions. However, higher initial cost is a barrier to the promotion of its use. Energy-pile and energy-slab are known as low cost ground heat exchangers comparing with conventional ground heat exchangers, because they utilize building structures as ground heat exchangers. This paper presents the daily cooling performance of a geothermal heat pump system with energy-pile and energy-slab. The energy-piles and the energy-slabs are connected to heat pump units in parallel. The cooling capacity of the system was nearly constant due to the stability of the ground heat exchangers. The stability of the energy-pile was a little higher than that of the energy-stab as a heat sink.

• Geomechanics and Engineering
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• v.24 no.6
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• pp.559-572
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• 2021

This research presents the monitoring results and their interpretation on load sharing of the pile foundation during the construction of a high-rise (124 m in height) building in Bangkok, in soft clayey ground. Axial forces in several piles, pore water pressure and earth pressures beneath the raft in a tributary area were monitored through the construction period of the building. The raft of the pile foundation in soft clayey ground can share the load up to 10-20% even though the foundation was designed using the conventional approach in which the raft resistance is ignored. The benefit from the return of ground water table as the uplift pressure is recognized. A series of parametric study by 3D-FEA were carried out. The potential of utilizing the piled raft system for the high-rise building with underground basement in soft clayey ground was preliminarily confirmed.

• Nuclear Engineering and Technology
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• v.53 no.12
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• pp.4179-4188
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• 2021

This study identifies efficient earthquake intensity measures (IMs) for seismic performances and fragility evaluations of the reactor containment building (RCB) in the advanced power reactor 1400 (APR1400) nuclear power plant (NPP). The computational model of RCB is constructed using the beam-truss model (BTM) for nonlinear analyses. A total of 90 ground motion records and 20 different IMs are employed for numerical analyses. A series of nonlinear time-history analyses are performed to monitor maximum floor displacements and accelerations of RCB. Then, probabilistic seismic demand models of RCB are developed for each IM. Statistical parameters including coefficient of determination (R²), dispersion (i.e. standard deviation), practicality, and proficiency are calculated to recognize strongly correlated IMs with the seismic performance of the NPP structure. The numerical results show that the optimal IMs are spectral acceleration, spectral velocity, spectral displacement at the fundamental period, acceleration spectrum intensity, effective peak acceleration, peak ground acceleration, A95, and sustained maximum acceleration. Moreover, weakly related IMs to the seismic performance of RCB are peak ground displacement, root-mean-square of displacement, specific energy density, root-mean-square of velocity, peak ground velocity, Housner intensity, velocity spectrum intensity, and sustained maximum velocity. Finally, a set of fragility curves of RCB are developed for optimal IMs.

• Structural Engineering and Mechanics
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• v.11 no.6
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• pp.663-672
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• 2001

Numerous failures in welded connections in steel moment-resisting building frames (SMRF) were observed when buildings were inspected after the 1994 Northridge Earthquake. These observations raised concerns about the effectiveness of such frames for resisting strong earthquake ground motions. The behavior of SMRFs during an earthquake must be assessed using nonlinear dynamic analysis, and such assessments must permit the deterioration in connection strength to capture the behavior of the frame. The uncertainties that underlie both structural and dynamic loading also need to be included in the analysis process. This paper describes the analysis of one of approximately 200 SMRFs that suffered damage to its welded beam-to-column connections from the Northridge Earthquake is evaluated. Nonlinear static and dynamic analysis of this SMRF in the time domain is performed using ground motions representing the Northridge Earthquake. Subsequently, a detailed uncertainty analysis is conducted for the building using an ensemble of earthquake ground motions. Probability distributions for deformation-related limit states, described in terms of maximum roof displacement or interstory drift, are constructed. Building fragilities that are useful for condition assessment of damaged building structures and for performance-based design are developed from these distributions.

• Earthquakes and Structures
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• v.5 no.6
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• pp.679-702
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• 2013

During an earthquake, soils filter and send out the shaking to the building and simultaneously it has the role of bearing the building vibrations and transmitting them back to the ground. In other words, the ground and the building interact with each other. Hence, soil-structure interaction (SSI) is a key parameter that affects the performance of buildings during the earthquakes and is worth to be taken into consideration. Columns are one of the most crucial elements in RC buildings that play an important role in stability of the building and must be able to dissipate energy under seismic loads. Recent earthquakes showed that formation of plastic hinges in columns is still possible as a result of strong ground motion, despite the application of strong column-weak beam concept, as recommended by various design codes. Energy is dissipated through the plastic deformation of specific zones at the end of a member without affecting the rest of the structure. The formation of a plastic hinge in an RC column in regions that experience inelastic actions depends on the column details as well as soil-structure interaction (SSI). In this paper, 854 different scenarios have been analyzed by inelastic time-history analyses to predict the nonlinear behavior of RC columns considering soil-structure interaction (SSI). The effects of axial load, height over depth ratio, main period of soil and structure as well as different characteristics of earthquakes, are evaluated analytically by finite element methods and the results are compared with corresponding experimental data. Findings from this study provide a simple expression to estimate plastic hinge length of RC columns including soil-structure interaction.

• Journal of the Ergonomics Society of Korea
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• v.34 no.5
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• pp.427-436
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• 2015

Objective: This study aims to analyze occupational accidents of parking lot attendants by parking lot type. Background: Recently, efforts are made to analyze accident characteristics by occupation type targeting the workers engaged in the same work. Method: This study analyzes 303 occupational accidents of parking lot attendants occurring from 2010 to 2012. Parking lots are grouped into two groups according to the work environment. One is public/ground type which comprises road side or open area parking lots and the other is building/mechanical type which comprises a multi-story parking building with connecting ramps and/or mechanical parking system. The characteristics of occupational accidents by parking lot type are analyzed. Results: Accident characteristics showed the difference between public/ground type and building/mechanical type on the size of enterprise, age, gender and work experience of the injured. Also the accident type, source of accident and parts of body affected are different between the two parking lot types. Conclusion and Application: The findings of accident characteristics according to parking lot types can be used as baseline data for establishing systemized preventative policies for occupational accidents of parking lot attendants.

• Korean Institute of Interior Design Journal
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• v.22 no.1
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• pp.28-37
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• 2013

Architecture of the present time has a general tendency that focuses only in its permanence between the structure and the ground. Architecture has the temporariness. In other words, it is a losing creation. Structure of natural building materials starts its life on the ground and also ends its life on there. Natural building materials leave no building wastes on their ground. Concerns about how to let materials contain not only its physical property but also their regional relation and timely temporariness can let us express materiality of natural building materials in modern construction spaces. And also, it will be the way of recovering the value of architecture and the healing human's sensibility. Kuma Kengo made an attempt that makes the best use of materiality in his work by using them in balance and draw new materiality by a fusion of them. In here, suggestion about the ways of using weak natural materials in modern construction spaces is the main object of this paper. And we can make a progress by analyzing Kuma's expression way of materiality in his work.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.213-214
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• 2012

This study is about the assessment of utilization possibility as a material for cementation of ground which is necessary for the reinforcement of soft ground by making environment-friendly inorganic composite utilizing inorganic recycled resources, and it was verified that it showed higher uniaxial compressive strength than the existing cementitious ground solidifier when it was applied as a combination material for soft ground such as dredge reclaimed land, and since an inorganic composite utilizing recycled resources such as high calcium fly ash and blast furnace slag etc. does never use cement, it is considered that it would be safe in the issue of a hexavalent chromium that was recognized as a problem of a cementitious solidifier.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.284-285
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• 2014

In this study, effects of pore structure of ground granulated blast-furnace slag concrete on freezing-thawing resistance are reviewed. As a result, degradation of freezing-thawing resistance performance was occurred as replacement ratio of ground granulated blast-furnace slag increases under same specified concrete strength condition. It is considered that pore structure of internal binder affects freezing-thawing resistance performance.

• Earthquakes and Structures
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• v.11 no.1
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• pp.109-127
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• 2016

This paper examines the contribution of three sources of uncertainties to probabilistic seismic behaviour of wood frame buildings, including ground motions, intensity and seismic mass. This sensitivity analysis is performed using three methods, including the traditional method based on the conditional distributions of ground motions at given intensity measures, a method using the summation of conditional distributions at given ground motion records, and the Monte Carlo simulation. FEMA P-695 ground motions and its scaling methods are used in the analysis. Two archetype buildings are used in the sensitivity analysis, including a two-storey building and a four-storey building. The results of these analyses indicate that using data-fitting techniques to obtain probability distributions may cause some errors. Linear interpolation combined with data-fitting technique may be employed to improve the accuracy of the calculated exceeding probability. The procedures can be used to quantify the risk of wood frame buildings in seismic events and to calibrate seismic design provisions towards design code improvement.