• Journal of the Korean Geotechnical Society
• /
• v.19 no.4
• /
• pp.211-221
• /
• 2003

The response displacement method is the most frequently used method for seismic design of underground structures. This method is pseudo-static method, and the evaluations of velocity response spectrum of seismic base and response displacement of surrounding soil are the most important steps. In this study, the evaluation of velocity response spectrum of seismic base according to the Korean seismic design guide and the simple method of calculating the response displacement were studied. It was found that velocity response spectrum of seismic base can be estimated by directly integrating the ground-surface acceleration response spectrum of soil type S$_A$, and the evaluation of the response displacement using double cosine method assuming two layers of soil profile shows the advantages in the seismic design.

• Journal of Korean Association for Spatial Structures
• /
• v.14 no.1
• /
• pp.77-84
• /
• 2014

Simple 3, 10, and 30-story buildings with a nonstructural element which is located at roof or near the middle of the building height are selected. Based on 2009 Korean Building Code, the seismic design force applied at the nonstructural element is evaluated. Response spectrum analysis is conducted with the design response acceleration spectrum of 2009 Korean Building Code and the analytical response is compared with the seismic design force from the Code. Furthermore, an artificial earthquake based on Korean design response acceleration spectrum and the 50% intensity of El Centro earthquake, which can be considered as the maximum future earthquake possibly occurring in Korea, are selected to conduct time history analysis. When the period of the nonstructural element is shorter than 0.06 second or longer than that of the 1st period of each building, the Code equations of seismic design force for nonstructural element seems to be appropriate. However, the period of the nonstructural element is close to the one of the building's higher mode periods including the 1st period, seismic force of the nonstructural element might exceed the Code specified seismic design force.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2003.03a
• /
• pp.110-117
• /
• 2003

The result of recent seismic hazard analysis indicates that the ground motion response spectra for Korean nuclear power plant site have relatively large high frequency acceleration contents. In the ordinary seismic fragility analysis of nuclear power plant structures and equipments, the safety margin of design ground response spectrum is directly used as a response spectrum shape factor. The effects of input response spectrum shape on the floor response spectrum were investigated by performing the direct generation of floor response spectrum from the ground response spectrum. The safety margin included in the design ground response spectrum should be considered as a floor response spectrum shape factor for the seismic fragility analysis of the equipments located in a building.

• Earthquakes and Structures
• /
• v.4 no.4
• /
• pp.341-363
• /
• 2013

Earthquake response calculation, parametric analysis and seismic parameter optimization of base-isolated structures are some critical issues for seismic design of base-isolated structures. To calculate the earthquake responses for such non-symmetric and non-classical damping linear systems and to implement the earthquake resistant design codes, a modified complex mode superposition design response spectrum method is put forward. Furthermore, to do parameter optimization for base-isolation structures, a graphical approach is proposed by analyzing the relationship between the base shear ratio of a seismic base-isolation floor to non-seismic base-isolation one and frequency ratio-damping ratio, as well as the relationship between the seismic base-isolation floor displacement and frequency ratio-damping ratio. In addition, the influences of mode number and site classification on the seismic base-isolation structure and corresponding optimum parameters are investigated. It is demonstrated that the modified complex mode superposition design response spectrum method is more precise and more convenient to engineering applications for utilizing the damping reduction factors and the design response spectrum, and the proposed graphical approach for parameter optimization of seismic base-isolation structures is compendious and feasible.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.09a
• /
• pp.1250-1257
• /
• 2009

Due to the improvement of the seismic hazard analysis method and the design code, dynamic analysis method is widely used. To conduct dynamic analysis, various coefficients should be designated. The time history acceleration is one of the most essential factor. However, strong earthquake motion data from the outside of the country have been used to conduct dynamic analysis without considering of the ground motion parameters. In this study, the methodology to choose appropriate input motion is developed by using time domain design spectrum matching procedure. Two examples are applied to verify the methodology. The Result shows that the methodology satisfies seismic circumstances and the design code.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.23 no.2
• /
• pp.109-117
• /
• 2019

In this study, a design procedure for the practical application of the dampers to building structures under earthquake loads was presented by using earthquake response spectrum. Nonlinear time history results using a 10 story building structure installed with damper verified the effectiveness of the proposed procedure by showing that the structural response could be reduced to the target performance level for seismic loads. Since the proposed design procedures are based on response spectrum seismic analysis result of the original structure, the capacity, location and the number of damper and the consequent response reduction effects can be preliminarily determined without performing the nonlinear time history analysis.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.7 no.4
• /
• pp.23-30
• /
• 2003

The result of recent seismic hazard analysis indicates that the ground motion response spectra for Korean nuclear power plant site have relatively large frequency acceleration contents. In the ordinary seismic fragility analysis of nuclear power plant structures and equipments, the safety margin of design ground response spectrum is directly used as a response spectrum shape factor. The effects of input response spectrum shape on the floor response spectrum were investigated by performing the direct generation of floor response spectrum from the ground response spectrum. The safety margin included in the design ground response spectrum should be considered as a floor response spectrum shape factor for the seismic fragility analysis of the equipments located in a building.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.23 no.6
• /
• pp.301-309
• /
• 2019

A methodology to assess seismic fragility of a nuclear power plant (NPP) using a conditional mean spectrum is proposed as an alternative to using a uniform hazard response spectrum. Rather than the single-scenario conditional mean spectrum, which is the conventional conditional mean spectrum based on a single scenario, a multi-scenario conditional mean spectrum is proposed for the case in which no single scenario is dominant. The multi-scenario conditional mean spectrum is defined as the weighted average of different conditional mean spectra, each one of which corresponds to an individual scenario. The weighting factors for scenarios are obtained from a deaggregation of seismic hazards. As a validation example, a seismic fragility assessment of an NPP containment structure is performed using a uniform hazard response spectrum and different single-scenario conditional mean spectra and multi-scenario conditional mean spectra. In the example, the number of scenarios primarily influences the median capacity of the evaluated structure. Meanwhile, the control frequency, a key parameter of a conditional mean spectrum, plays an important role in reducing logarithmic standard deviation of the corresponding fragility curves and corresponding high confidence of low probability of failure (HCLPF) capacity.

• Journal of Applied Reliability
• /
• v.12 no.3
• /
• pp.201-213
• /
• 2012

A gear type lubrication pump is an essential component of the powertrain and has a major role for supplying oil to the gears and bearings in automatic transmission with a hydraulic clutch. Therefore, the durability test code design of lubrication pump is very important to ensure the reliability of the entire transmission and the vehicle. In this study, the design process for the life testing of lubrication pump has been generalized by four steps. The four design steps of the life testing of lubrication pump consist of the configuration of load spectrum, rain flow counting and analysis of load level, the equivalent damage assessment and test code generation. In fact, the load spectrum should be obtained from the field operating condition but that kind of data is the top secret of manufacturers. This is not open to the public in general. So we could use the artificially simulated load spectrum instead of field obtained one and focused on the development of the general process for designing the life test of a gear type lubrication pump. Reliability goals for lubrication pump, pressure, torque, temperature and load spectrum, if present, as appropriate for the given test conditions, accelerated life testing for the lubrication pump can be designed by the developed design steps.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.21 no.1
• /
• pp.31-39
• /
• 2017

In this study, to estimate the combination of earthquake magnitude ($M_w$) and distance (R) corresponding to the design spectrum defined in Korean Building Code (KBC) 2016, the response spectra predicted from the attenuation relationships with the variation of $M_w$ (5.0~7.0) and R (10~30km) are compared with the design spectrum in KBC 2016. Four attenuation relationships, which were developed based on local site characteristics and seismological parameters in Southern Korea and Eastern North America (ENA), are used. As a result, the scenario ground motions represented by the combinations of $M_w$ and R corresponding to the design spectrum for Seoul defined in KBC 2016 are estimated as (1) when R =10 km, $M_w=6.2{\sim}6.7$; (2) when R = 15 km, $M_w=6.5{\sim}6.9$; and (3) when R = 20 km, $M_w=6.7{\sim}7.1$.