• Structural Engineering and Mechanics
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• v.40 no.4
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• pp.489-500
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• 2011

The elastic seismic response of plan-asymmetric multi storey steel-frame buildings is investigated under earthquake loading with particular emphasis on forward-rupture directivity and fling records. Three asymmetric building systems are generated with different torsional stiffness and varying static eccentricity. The structural characteristic of these systems are designed according to UBC 97 code and their seismic responses subjected to a set of earthquake records are obtained from the response history analysis (RHA) as well as the linear static analysis (LSA). It is shown that, the elastic torsional response is influenced by the intensity of near-fault ground motions with different energy contents. In the extreme case of very strong earthquakes, the behaviour of torsionally stiff buildings and torsionally flexible buildings may differ substantially due to the fact that the displacement envelope of the deck depends on ground motion characteristics.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.757-762
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• 2000

The purpose of this study is to investigate the performance of slab-beam-column subassemblage in the Ordinary Moment Frame(OMF). For this purpose, 3-story building was designed according to UBC and ACI building code(ACI 318-99) and the subassemblages of in the first story were constructed. The subassemblages were classified into interior and exterior. Each interior and exterior subassemblage is modeled by the 2/3 scale experimental specimens. All the specimens have the transverse beam and the columns on the slab have the lap splice as the typical exterior and interior slab-beam-column subassemblage. The interior subassemblage was tested under the constant axial force, while the exterior subassemblage was tested under the fluctuating axial force. Based on the results of the experiments, the performance of each subassemblage is evaluated and the failure mode is investigated.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.10a
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• pp.201-208
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• 1997

In most seismic codes such as the Uniform Building Code(UBC), the response modification factor(or the force reduction factor)is used to reflect the capability of a structure in dissipating energy through inelastic behavior. The response modification factor is assigned according to structural system type. Ductile systems such as special moment-resisting steel frames are assigned larger values of the response modification factor, and are consequently designed for smaller seismic design forces. Therefore, structural damage may occur during a severe earthquake. To ensure safety of the structures, the suitability of the response modification factor used in aseismic design procedures shall be evaluated. The object of this study is to develop a method for the evaluating of the response modification factor. The validity of the evaluating method has been examined for several cases of different structures and different earthquake excitations.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.289-296
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• 1999

In order to develop and enhance our methodology of seismic design in the next generation thee is a need to analyze the environment chronicles and concept of the seismic design in foreign countries. For this purpose we have researched the cases of U.S.A and Europe. In this paper the emphasis was put on the european seismicity and seismic design practices for building structures. In this study the comparison of seismic design codes in some european countries regarding fundamental period and design base shears leads to the conclusion that there exists remarkable difference in the approaches. Particularly the base shears used in european countries give larger values than the one proposed by UBC 97. Though each european country has established similar seismic design code there are also still large difference in the level of construction technology and societal implementation of seismic codes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.250-255
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• 2017

When an earthquake occurs, it is necessary to evaluate the site-specific ground response while considering ground characteristics in seismic design. The design seismic force of Korean seismic design criteria is borrowed from the Uniform Building Code(UBC-1997). However, the criteria are based on the ground characteristics of the United States, which are different from the ground characteristics in Korea, and using them could cause over-or under-designing. Therefore, it is important to develop a proper design response spectrum for Korean ground characteristics. In this study, 158 ground sites in Korean urban areas were selected and compared to those in the western part of the United States, and their site-specific ground responses were analyzed. The classification standard in the seismic design criteria classifies the 158 sites into 37 sites, 107 sites, and 14 sites. Using 7 earthquake inputs, the criteria were compared for each group.The Korean design response spectrum underestimates the amplification of the short-period range and overestimates the amplification in the long-period range. There were large differences in the results of the and sites,which account for 77 percent of the 158 sites. Therefore, there is a need to modify the amplification factor in the Korean seismic criteria to properly reflect Korean ground characteristics.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.777-784
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• 2010

In the current Korean seismic design guide, the site classification and the corresponding site coefficients were determined based on the UBC-1997 (Uniform Building Code). In order to develop the current site classification system, it is important to compare the local site conditions in Korea to other countries which have similar seismic design guides. In the eastern United States, New York City(40degrees 45minutes north latitude, 73degrees 59minutes west longitude) suggested that current design guidelines are unsuitable to shallow bedrock depth sites. So the 3-parameter methods are performed for new criteria in New York City. In this study, site response analyses were performed at 181 study sites using one-dimensional equivalent linear to evaluate the site-specific earthquake ground motions at inland areas in the Korean peninsula and reclassify the results according to similar ground motions using the 3-parameter methods. It is effective that multi-parameter methods for Korean site characteristics in comparison with single parameter method.

• Structural Engineering and Mechanics
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• v.45 no.2
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• pp.233-257
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• 2013

Given the yield shear of a single-story inelastic structure with simple eccentricity, the problem of strength distribution among the resisting elements is investigated, with respect to minimize its torsional response during a ground motion. Making the hypothesis that the peak accelerations, of both modes of vibration, are determined from the inelastic acceleration spectrum, and assuming further that a peak response quantity is obtained by an appropriate combination rule (square root of sum of squares-SRSS or complete quadratic combination-CQC), the first aim of this study is to present an interaction relationship between the yield shear and the maximum torque that may be developed in such systems. It is shown that this torque may be developed, with equal probability, in both directions (clockwise and anticlockwise), but as it is not concurrent with the yield shear, a rational design should be based on a combination of the yield shear with a fraction of the peak torque. The second aim is to examine the response of such model structures under characteristic ground motions. These models provide a rather small peak rotation and code provisions that are based on such principles (NBCC-1995, UBC-1994, EAK-2000, NZS-1992) are superiors to EC8 (1993) and to systems with a stiffness proportional strength distribution.

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.1
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• pp.57-67
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• 1997

The objective of present paper is to investigate elasto-plastic behaviour and estimate the resistance capacity of a beam-shear wall structural system against earthquake ground accleration exciations. Pushover analysis is adopted to estimate inttiate and post stiffnesses and yielding point for inelastic response analysis in LPM (Lumped Parameter Mass) model, and modified Clough model is used as the hysteresis rule of each story. Three earthquake waves are used in the analysis but their peak ground accelerations are changed to be 0.12g, 0.24g. It is assumed that the earthquakes act in the longigtudianl direction of a 25 Story apartment building which consists of two some unit plan. The distribution of story ratio and ductility ratio are estimated and discussed within Korean, Japanese code and UBC.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.6
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• pp.629-636
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• 2011

It has been suggested that buildings designed for strong ground motions will also have improved resistance to air blast loads. As an initial attempt to quantify this behavior, the responses of a ten story steel building, designed for the 1994 building code, with lateral resistance provided by perimeter moment frames, is considered. An analytical model of the building is developed and the magnitude and distribution of blast loads on the structure are estimated using available computer software that is based on empirical methods. To obtain the relationship between pressure, time duration, and standoff distance, these programs are used to obtain an accurate model of the air blast loading. A hemispherical surface burst for various explosive weights and standoff distances is considered for generating the air blast loading and determining the structural response. Linear and nonlinear analyses are conducted for these loadings. Air blast demands on the structure are compared to current seismic guidelines. These studies present the displacement responses, story drifts, demand/capacity ratio and inelastic demands for this structure.

• Computational Structural Engineering
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• v.9 no.4
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• pp.229-237
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• 1996

In some current procedures, ground motions from different sources have been scaled by their peak ground accelerations and combined to obtain smoothed response spectra for specific regions. As consideration of the inelastic deformation capacity of structure, inelastic deformations are permitted under seismic ground excitation in all codes. In the ATC(Applied Technology Council) and UBC(Uniform Building Code), the inelastic design spectrum is obtained by reducing the elastic design spectrum by a factor that is independent of structural period. In this study, the average of nonlinear response spectra calculated from a sample of 20 records for each event are constructed to obtain the smoothed response spectra. These response spectra are used to examine the effects of structural strength factors such as the yield strength ratio and damping value. Through the regression analysis of nonlinear response of system for a given damping value and yield strength ratio, the required yield strength for seismic design can be estimated for a certain earthquake event. And a response modification coefficient depending on the natural period for current seismic design specifications are proposed.