• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.04a
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• pp.88-96
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• 1995

Seismic design provisions in Korea has developed based on seismic provisions in United States (e.g., ATC 3-06). Current seismic design provisions in U .S. is moving toward adopting enhanced concept for design. Federal Emergence Management Agency (FEMA) Provides the NEHRP recommended Provisions for the Development of Seismic Regulations for New Buildings which can be used as a source document for use by any interested members of the building community. Current seismic design provisions in U .S. generally use a uni-level force. These provisions can not be satisfied if the limit state design is concerned. Limit state can be defined as a state causing undesirable performance o( a structure (e .g., serviceability, ultimate, buckling, etc.). Even if there are provision for controlling drift by two levels, it is still difficult to satisfy limit states using uni-level force. Architectural Institute of Japan (AIJ) uses a hi-level forces Int seismic loadings which can satisfy serviceability and ultimate limit state. However, the seismic parameters used in AIJ guideline are basically determined by subjective manner of code committee member and professions. These parameters need to be determined based on target quantities (target reliability, target energy dissipation, target displacement, target stress level, etc.). This study develops the method to determine the sesmic design parameters based on a certain taget level. Reliability is used as a target level and load factors in ANSI/ASCE 7-88 are selected as design parameters to be determined.

• Computational Structural Engineering : An International Journal
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• v.2 no.1
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• pp.11-17
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• 2002

Cost-effectiveness in design is considered for determining the target reliability of concrete bridges under seismic actions. This objective can be achieved based on the economic optimization of the expected life-cycle cost of a bridge, which includes initial cost, direct losses, and indirect losses of a bridge due to strong earthquakes over its lifetime. A separating factor is defined to consider the redundancy of a transportation network. The Park-Ang damage model is employed to define the damage of a bridge under seismic action, and a Monte Carlo method based on the DRAIN-2DX program is developed to assess the failure probability of a bridge. The results for an example bridge analyzed in this paper show that the optimal target failure probability depends on the traffic volume carried by the bridge and is between 1.0×10/sup -3/ to 3.0×10/sup -3/ over a life of 50 years.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.3
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• pp.224-229
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• 2009

Partial safety factors(PSFs) for Level I reliability based design of caisson type quay walls were calculated. First order reliability method(FORM) based PSFs are the functions of sensitivities of limit state function with respect to design random variables, target reliability index, characteristic values and first moment of random variables. Modified PSFs for water level and resilient water level are newly defined to keep consistency with the current design code. In the numerical example, PSFs were calculated by using a target reliability index. Seismic coefficient is defined to show extreme distribution. It was found that PSFs for seismic coefficient becomes smaller as the return period for design seismic coefficient grows longer.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.3
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• pp.249-259
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• 2020

Design criteria for limit state design of underground structures have already been published overseas, and research has been conducted to revise the design method in Korea. In order to estimate the probability of failure under seismic load, the probability variable should be considered in the reliability analysis. In this study, the failure probability of the existing shield tunnel segment lining design was calculated by applying the coefficient of variation (COV) for the earth pressure and the seismic load effect in consideration of the statistical characteristics of the domestic ground properties. Based on the results of calculating the reliability index (β) from the calculated probability of failure and analyzing the reliability index according to the change in the load factor and the results of domestic and foreign research, the target reliability index (β_T) during earthquakes of shield tunnel segment lining is analyzed to be "2.3", it was proposed as the target reliability index for the design of the limit state under seismic load.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.2
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• pp.9-22
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• 2008

This paper presents an integrated optimal design technique of a hybrid structure-damper system for improving the seismic performance of the structure. The proposed technique corresponds to the optimal distribution of the stiffness and dampers. The multi-objective optimization technique is introduced to deal with the optimal design problem of the hybrid system, which is reformulated into the multi-objective optimization problem with a constraint of target reliability in an efficient manner. An illustrative example shows that the proposed technique can provide a set of Pareto optimal solutions embracing the solutions obtained by the conventional sequential design method and single-objective optimization method based on weighted summation scheme. Based on the stiffness and damping capacities, three representative designs are selected among the Pareto optimal solutions and their seismic performances are investigated through the parametric studies on the dynamic characteristics of the seismic events. The comparative results demonstrate that the proposed approach can be efficiently applied to the optimal design problem for improving the seismic performance of the structure.

• Computers and Concrete
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• v.20 no.6
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• pp.719-729
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• 2017

A considerable research is available on the seismic response of Reinforced Concrete (RC) shear wall-frame buildings, but the studies on the reliability of such buildings, with the consideration of human error, are limited. In the present study, a detailed procedure for reliability assessment of RC shear wall-frame building subjected to earthquake loading against serviceability limit state is presented. Monte Carlo simulation was used for the reliability assessment. The procedure was implemented on a 10-story RC building to demonstrate that the shear walls improve the reliability substantially. The annual and life-time failure probabilities of the studied building were estimated by employing the information of the annual probability of earthquake occurrence and the design life of the building. A simple risk-based cost assessment procedure that relates both the structural life-time failure probability and the target reliability with the total cost of the building was then presented. The structural failure probability (i.e., the probability of exceeding the allowable drift) considering human errors was also studied. It was observed that human error in the estimation of total load and/or concrete strength changes the reliability sharply.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.37-44
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• 2019

The purpose of this study is to rationally determine the priority of seismic reinforcement of main(key) members of bridges. Cable Supported bridge was selected as the evaluation target and the reliability based on the probability distribution was used to evaluate the seismic fragility of the key members as a quantitative indicator. The safety factor, which is a random variable, is considered an artificial (fixed load and live load) load and a natural (earthquake, wind, temperature, etc.) load. The seismic load is applied as a possible earthquake during the lifetime of the bridge. From analyzing the fragility of each key member based on the seismic reliability, it can be concluded that the shoe (23.8%) was the most fragile, where the other members are ranked as place concrete (20.5%), pier (18.9%), foundation (17.3%) and cable (5.0%) respectively.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.422-428
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• 2011

Optimal reliability indices were found by optimizing life cycle cost(LCC) of pier type quay walls. Failure probability of pier and shore bridge were calculated by response surface method. Then, they were used to obtain recovery cost after damage. Costs for initial construction and maintenance were also considered in finding optimal reliability indices. Target reliability indices which may be used in reliability based design were suggested by numerical examples under seismic load and ship load.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.1
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• pp.19-26
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• 2018

After the Gyeongju earthquake, school buildings were designated as earthquake shelters. However, the ratio of designed for seismic of domestic school buildings is only 23.2% in Korea, and it is necessary to secure the seismic safety of those. Therefore, in this paper, a target building was selected before the seismic design criteria was established and the seismic performance of the building was evaluated. After the evaluation, reinforcement of the building was carried out using seismic retrofit systems which was previously tested. For this purpose, the evaluation was carried out using OpenSees program and the reliability of the seismic retrofit systems was also verified. In this way, we can more precisely reproduce the response of the building in case of actual earthquake and predict damage of the earthquake in the future.

• Earthquakes and Structures
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• v.7 no.1
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• pp.101-117
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• 2014

This paper presents a reliability-based analysis on seismic performance of timber-steel hybrid shear wall systems. Such system is composed of steel moment resisting frame and infill wood frame shear wall. The performance criteria of the hybrid system with respect to different seismic hazard levels were determined through a damage assessment process, and the effectiveness of the infill wood shear walls on improving the seismic performance of the hybrid systems was evaluated. Performance curves were obtained by considering different target non-exceedance probabilities, and design charts were further established as a function of seismic weight. Wall drift responses and shear forces in wood-steel bolted connections were used as performance criteria in establishing the performance curves to illustrate the proposed design procedure. It was found that the presence of the infill wood shear walls significantly reduced the non-performance probabilities of the hybrid wall systems. This study provides performance-based seismic evaluations on the timber-steel hybrid shear walls in support of future applications of such hybrid systems in multi-story buildings.