Cyclic constitutive relations of high performance fiber reinforced cementitious composites

신경준 Seoul National Univ. 2006 국내박사

Analysis of buried pipeline response subjected to underground blasting with consideration of soil-pipe interaction

Hai, Dang Nguyen Graduate School, Yonsei University 2010 국내석사

The objective of this research is to record ground motions (displacements, velocities and accelerations) and analyze the stresses on a buried pipeline induced by underground blasts. The validity of the developed methodology is verified by comparing with the previous experimental results. In addition, several particle velocity prediction equations will be reviewed. The pipe stress data are used to develop safe blasting criteria for buried pipelines.Normally, the ground shock motions induced by underground blasts are of major concerns to designers in mining, construction and defense engineering. The ground shocks are usually measured by the peak particle velocity (PPV) which is considered the best measure of damage potential. Up to the present, the seismic analysis and behavior of buried pipelines have been experimentally investigated by many researchers and organizations. There have been various empirical formulae exist for the prediction of PPV as a function of the scaled distance (SD) for given geological site conditions. The seismic response analysis of buried pipelines is somewhat complex since it considers the three-dimensional (3D) dynamic behavior of the soil-pipeline interaction under blasting excitations. Thus, simplified methods are developed to obtain reliable response characteristic of the pipeline under the blast loads. In the scope of this research, several FE analyses are conducted to determine ground vibration quantities at the ground and surrounding the pipelines. Numerical models of buried pipelines and surrounding soil in FEM code are divided into two main groups with variety of explosive configuration, namely, single charge and multiple parallel charges. The maximum pipe stresses induced by the blasts are computed in the circumferential and longitudinal directions. In addition to the pipe stress and ground motion results, extensive discussions on delays are also presented to get the optimal delay of multiple blasting. The results of analysis utilized to develop safe blasting criteria for buried pipelines with the need to protect it from blast damage. As a result of the research, improved prediction of safety scaled distance will be derived with single and line sources detonated in soil.

System integration framework through development of STEP-based information model for steel bridges

정연석 Graduate School, Yonsei University 2006 국내박사

Development of information systems such as intelligent monitoring systems, decision making systems, and bridge management systems for supporting life-cycle processes of bridges has made considerable progress. However, since these information systems cannot encompass engineering information of structures, it is difficult to solve practical engineering problems related to bridge structures. This study presents a new strategy, which can guarantee the consistency of engineering information of steel bridges, for the prompt and accurate information service to support quick assessment of structural safety and usability of bridges in an integrated computing environment.This study developed the information model that electronically represent information on project plan, structural analysis and structural design of steel bridges. The information model is based on the STEP standard, which is an open standard, so it can be used as data structures for building a database. Since the information model includes integrated resources of STEP to represent 3D geometric shape and structural analysis information of steel bridges, the built database allows end-users to use the output data of existing systems. The model represents the structural design information of steel bridges into part and assembly information in accordance with product configuration defined by the manufacturing domain. This development method for defining product configuration gives flexibility to the model developers in representing structural design information of steel bridges. This integrated database based on the information model is expected to provide practical engineering information of steel bridge structures to information systems for operation and maintenance of facilities.This study presents the framework for integration of application programs such as the existing CAD/CAE/CAx programs used in practice by applying the STEP-based information model and information technologies. With the system integration framework composed of the information model, data repository, application program, and application programming interface, the physical data generated by each field of civil engineering can be used in practice. This study developed a prototype system according to the system integration framework so that end-users can manage information of steel bridges in an integrated computing environment. Especially, application programs of the prototype system can perform structural analysis and design of steel bridge on the commercial CAD program with an ACIS solid modeling kernel, providing 3D solid modeling capability. With this application program, end-users can collaborate by accessing a remote database via the internet and TCP/IP protocol.This study also presents the method to automatically generate a structural analysis model from structural design information. This method is performed by the full connection between structural analysis and structural design information by using the structured information models. The structural design information of a steel bridge should be updated during the lifetime of the bridge, as a result of maintenance works such as retrofitting, restoration, rehabilitation, etc. Whenever structural design information is changed, the structural analysis information should also be changed and maintained in preparation against emergent situations, e.g. earthquakes, floods, terrors, etc. The automatic generated model is useful not only for performing structural analysis in periodic evaluations of steel bridges, but also for quick assessment of bridges in emergent situations.By using these technologies, this study is expected to present a better computing environment for supporting work processes over the life-cycle of bridges. 교량의 유지관리를 목적으로 지능형모니터링시스템, 의사결정시스템 및 교량유지관리시스템과 같이 다양한 정보시스템들에 대한 연구개발이 상당히 진전되어 오고 있다. 그러나 이러한 정보시스템들은 교량 구조물의 엔지니어링 정보를 다룰 수 없기 때문에 구조물과 관련된 실질적인 문제를 해결하기는 여전히 어렵다. 따라서 본 연구에서는 통합된 전산환경 하에서 교량의 사용성 및 구조물의 안전성 평가를 신속하게 지원하고 정확한 정보 서비스가 가능하도록 정보의 일관성을 보장할 수 있는 새로운 전략을 제시한다.통합된 전산환경 구축을 위한 핵심기술은 표준화된 정보를 기반으로 한 데이터베이스이다. 이에 본 연구에서는 강교량의 프로젝트 정보, 구조해석정보 및 구조설계정보를 전자적으로 표현하는 정보모델을 개발하였다. 정보모델은 개방형 표준인 STEP을 기반으로 개발되었으며 통합 데이터베이스를 구축하기 위한 데이터구조로 사용된다. 개발된 정보모델은 강교량의 구조해석정보와 3차원 기하형상정보를 표현하기 위해서 STEP의 통합자원을 포함하였기 때문에, 구축된 통합 데이터베이스는 사용자로 하여금 기존 시스템의 결과로 생성된 정보를 사용할 수 있도록 해준다. 강교량 정보모델은 제조산업에서 정의하는 제품의 구성체계에 입각하여 구조설계정보를 단품과 조립품으로 표현하였다. 제품의 구성체계에 따른 정보모델 개발 방법은 특히, 모델 개발자로 하여금 강교량의 구조설계정보를 유연하게 표현할 수 있도록 해준다. 이와 같은 정보모델에 기반한 통합 데이터베이스는 사회기반시설물의 운용 및 관리를 위한 정보시스템에 강교량 구조물의 실질적인 엔지니어링 정보를 제공할 것으로 기대된다.본 연구에서는 STEP을 기반으로 개발된 정보모델과 정보기술들을 이용하여 실무에서 사용되는 기존의 CAD/CAE/CAx 프로그램과 같은 응용프로그램들을 통합하기 위한 프레임워크를 제시하였다. 정보모델, 데이터저장소, 프로그래밍 인터페이스 및 응용프로그램으로 구성된 프레임워크는 토목 엔지니어링에서 발생하는 물리적 데이터를 실무에서 사용할 수 있는 환경을 구축해 준다. 본 연구에서는 사용자가 통합 전산환경에서 강교량 정보를 관리할 수 있도록 시스템 통합 프레임워크에 따른 프로토타입 시스템을 개발하였다. 특히, 프로토타입 시스템의 응용프로그램들은 3차원 솔리드모델링 기능을 제공하는 ACIS 커널을 장착한 AutoCAD 프로그램에서 구조해석과 구조설계를 수행한다. 이러한 응용프로그램을 이용하여, 사용자는 인터넷을 경유하여 원격지 통합 데이터베이스에 접근함으로써 강교량 정보를 사용할 수 있다.본 연구에서는 구조설계정보로부터 구조해석모델을 자동생성하기 위한 방법을 또한 제시한다. 강교량의 구조설계정보는 유지보수로 인해 교량의 생애주기 동안에 업데이트 되어야 한다. 구조설계정보가 변경될 때마다, 구조해석정보가 긴급한 상황에 대처할 수 있도록 또한 변경되어야 한다. 이러한 문제점에 대처하기 위해서, 자동생성된 구조해석정보는 강교량의 주기적 평가에서 구조해석을 수행하기 위해서 사용될 뿐 아니라, 긴급한 상황 시에 신속한 평가를 위해서도 사용될 수 있다.마지막으로, 본 연구는 다른 구조물이이나 다른 분야로부터 생성된 정보를 STEP과 같은 개방형 표준을 기반으로 한 시스템 통합 프레임워크에 적용한다. 이러한 기술들을 이용함으로써, 본 연구는 교량의 생애주기 동안에 업무프로세스를 지원하기 위한 향상된 전산환경을 제공할 것으로 기대된다.

Implementation of paperless design review for the U.S. Army's Yongsan Relocation Plan in Korea

Clark, Ryan Graduate School, Yonsei University 2013 국내석사

The advent of information and communication technology (ICT) has played a crucial role in evolving the architect/engineering/construction (A/E/C) field worldwide. The fusion of the World Wide Web and CAD software has created an opportunity for engineers to work together on a global scale to produce designs on time and within budget. By leveraging the use of technology throughout the design stage, architects and engineers can enhance the effectiveness of their communication and use of information which ultimately results in higher design quality. In this paper, the efficacy of paperless design reviews for a large government engineering and construction program in Korea is explored. By utilizing ICT via the internet, intranets, and software, the U.S. Army Corps of Engineers is able to exploit its knowledgebase and expertise distributed geographically throughout the Pacific. Implementation efforts of paperless design reviews are captured in this study to include the obstacles and benefits experienced throughout implementation. Lessons learned and future applications of this implemented effort are offered for consideration. A case study is finally presented showing the practical effects of the paperless design review method and its success in saving costs.

Seismic behavior of steel moment frames with rigid and semi-rigid connections

권 창모 Dept. of Civil Engineering, University of Californ 2000 국내석사

Analysis of Deep Foundation Behavior Using Fiber Optical Sensor

유 에코, 유영 Graduate School of Kumoh Natinal Institute of Tech 2006 국내박사

Fiber optic sensor is the ideal transducer for civil structural monitoring. Being durable, stable and insensitive to external perturbations, they are particularly interesting for the long-term health assessment of civil structures. BOTDR distributed sensing technology is the first trying for pile monitoring. The philosophy of monitoring using FOS is very similar to philosophy of finite element method: the structure is divided in elements, called cells, and each cell is equipped with a combination of sensors, called topology. The topology is particularly adapted to efforts expected in the cell, e.g. in case of pure traction or compression the topology consists of single sensor installed parallel to the axis of cell, while in case of bending the topology consists of four sensor lines attached evenly and to the axis of the cell. Using appropriate algorithms, the behaviour of different cells is correlated and monitoring at global structural level is performed. The aim of this paper is to present the application examples of BOTDR in pile foundation and to highlight its performances through the measuring results from driving procedures, set-up procedure, and static loading test. Moreover, it provides more information about normal force distribution, locked residual driving stresses, axial compression, bend tensile, bend compressive.

Flexural and shear strength of prestressed ultra high strength fiber reinforced concrete composite girders

우샹궈 Kumoh National Institute of Technology 2008 국내박사

Flexural and Shear Strength of Prestressed Ultra High Strength Fiber Reinforced Concrete Composite Girders Xiang - Guo Wu Department of Civil Engineering, Graduate School Kumoh National Institute of Technology Abstract Ultra-High Performance Fiber-Reinforced Concretes (UHPFRC) has high compressive strength and exhibit strain hardening behavior. Post tensioned UHPFRC composites girder is a new type composites structure and application of UHPFRC material. Composites responses influence the main structural behavior including ultimate flexural and ultimate shear. The objectives of the study are to proposed estimate formula for ultimate loading capacity and cracking loading capacity. Towards this subject, the current knowledge of UHPFRC properties is to be modeled in order to predict the structural behaviour of such composite elements and to make recommendations for the main failure modes evaluations, i.e. flexural cracking load, ultimate flexural state and ultimate shear state, diagonal shear cracking load, ultimate shear connection capacity. Experimental programs are performed to characterize the UHPFRC and determine the structural behaviour of composite elements through two full-scale UHPFRC composites and four full-scale UHPFRC girders with two kinds of mixing proportion UHPFRC. Prestressing losses are investigated during six weeks starting from the post tensioned UHPFRC girders. After the long-term measurements, two girders embedded with shear connectors are casted with Normal Concrete slab (NC). All the UHPFRC girder and composites are loaded under three point bending tests. Push tests are also carried out with the UHPFRC sandwich specimens to obtain the interfacial shear connection behavior which is the basis of the longitudinal interface shear analysis. Two shear connection parameters i.e. the initial elastic stiffness and slippage capacity are certificated as two constant parameters. Ultimate flexural strength of UHPFRC composites and UHPFRC girder are analyzed. An overlapping method of the initial internal moment and the additive flexural moment is proposed to avoid the traditional complicate stress distribution of post tensioned girder. An equivalent rectangular tensile stress block is derived to simplify the flexural tensile stress distribution of UHPFRC girder. The initial internal moment of UHPFRC girder due to the effective prestressing stress is derived. Cracking loading capacity of UHPFRC composites and girder are also obtained. Full interaction behavior can be assumed at the mid-span section of the girder and ensure the compatibility response of the two elements. Finally, the moment capacity is obtained by superimposing of the additive moment due to extra loading with the initial internal moment. Overlapping method is also used to obtain the moment capacity of post tensioned UHPFRC girder. Calculation of the test specimens are carried out to predict the ultimate flexure strength and cracking loading capacity of UHPFRC composites and UHPFRC girder. Some parameters influences are discussed on the ultimate flexural capacity of post tensioned UHPFRC composites and girder. The ultimate flexural loading capacity formulae are simplified with the neglect of the bottom flange part in the equivalent tensile stress block. This part influence is small from the comparison analysis. Based on two bounds theory which is an extension of the classical limit plasticity theory, ultimate shear behavior is investigated based on three point bending UHPFRC composites and UHPFRC girder. Beside the fiber parameters of fiber volume fraction, fiber length, diameter, interfacial bonding strength and tensile strength, fiber orientation is also considered in the fiber reinforcing model based on fiber uniform distribution assumption. This fiber reinforcing model is used to analyze the ultimate shear loading capacity and diagonal cracking loading capacity of UHPFRC composites and UHPFRC girder. Upper bound is derived based on the kinematical admissible failure mechanism and the low bound is derived based on cracking moment equilibrium analysis. According to the uniqueness theorem, the interaction of the two bounds constitutes the ultimate diagonal shear strength of UHPFRC structure. The two bounds expression is simplified approximately with constant diagonal cracking angle assumption. Some parameters influences on the ultimate shear strength are also analyzed. First diagonal cracking loading capacity formula is proposed based on the upper bound simplification by ignoring the influences of the fiber reinforcement. Beside the two bounds model, strut-tie models are constructed with strut compressive failure mode and strut splitting failure mode. Comparisons show that the two bounds theoretical model predictions and strut splitting failure model predictions are closer to the ultimate diagonal shear failure load of post tensioned UHPFRC composites girder. For short span UHPFRC girder, large gap exists between the loading capacity of UHPFRC composites and UHPFRC girder. However, the gap decreases with the increasing of the span length of UHPFRC girder. For long span UHPFRC girder, the gap is small. This indicate the composites strengthen response is significant for short span girder and non-significant for long span girder. Longitudinal interface shear force of UHPFRC composites is derived based on the linear elastic assumption. Two parameters of shear connection i.e. the initial elastic modulus and slippage capacity are obtained from the lateral direct push test of UHPFRC composites specimen. Test results proof that the initial elastic modulus and slippage capacity are two constant parameters of UHPFRC composites interface shear connection which is similar with steel composites interface shear characters. Shear connection degree is an important design parameter and it is the basis of criterion of full shear connection and partial shear connection. The ultimate state of longitudinal interface shear is assumed as the cracking state of the UHPFRC girder to define the shear connection degree which is a key parameter of the interface shear connection design. The shear connection degree can be used for the estimation of shear connector design. Calculations of the interface shear force and interface slippage are carried out. Based on the shear interfacial force distribution, shear connectors placement technology is recommended finally. Since cracking propagation of UHPFRC girder can influence the longitudinal interface shear force, the ultimate state of UHPFRC girder is different with the ultimate state of traditional steel composites girder, linear elastic interface analysis is certificated as the main character. The formulae of the ultimate flexural and ultimate shear of post tensioned UHPFRC composites girder and UHPFRC girder are proposed which can be used to estimate the ultimate loading capacity of UHPFRC composites and girder. Beside the ultimate flexural and ultimate shear, the formulae of the flexural cracking loading capacity and the diagonal cracking loading capacity of the composites and girder are also proposed which can be used to estimate the cracking loading capacity of flexural and diagonal cracking for post tensioned UHPFRC composites and girder. The simplifications of the ultimate flexural and ultimate shear are more convience for practical UHPFRC ultimate behavior estimations. Flexural and Shear Strength of Prestressed Ultra High Strength Fiber Reinforced Concrete Composite Girders Wu Xiang-Guo Department of Civil Engineering, Graduate School Kumoh National Institute of Technology 요약 UHPFRC 합성거더는 새로운 형태의 합성 구조물로서, 구조적으로 강합성 거더와는 다른 거동 특성을 보인다. 본 논문에서는 UHPFRC 합성부재 및 거더에 대한 구조실험을 수행하고, 실험결과를 바탕으로 포스트텐션 방식의UHPFRC 거더 및 합성부재에 대해 극한 휨강도, 극한 전단력, 휨균열, 사인장 전단균열 및 합성계면에서의 전단균열저항력 등에 대한 구조해석을 실시하였다. 구조해석 시 적용한 섬유보강 모델은 섬유혼입률, 섬유길이, 섬유직경, 섬유와 매트릭스의 부착강도, 섬유의 인장강도와 같은, 섬유와 관련한 변수뿐만 아니라 섬유의 방향성도 고려하였으며, 섬유는 임의적으로 분포되어 있어 모든 방향에 대해 동일한 확률로 분포하는 것으로 가정하였다. 섬유보강 모델은 UHPFRC 합성부재 또는 거더에서의 극한 전단력 산정 및 사인장 균열 발생 하중을 산정하기 위한 상한계, 하한계 모델에 적용되었다. UHPFRC 합성부재의 전단연결 성능은 합성단면에서의 전단력 평가를 통해 이루어졌다. 본 연구에서는 포스트텐션 방식의 UHPFRC 거더 및 합성부재의 내하력 평가가 가능하도록 극한 휨강도 및 전단력에 관한 모델식을 간편식의 형태로 제안하였다. 또한 포스트텐션 방식의 UHPFRC 거더 및 합성부재에 대해 균열발생 하중을 평가할 수 있도록 휨균열 및 전단균열 발생강도에 관한 모델식을 제안하였다. 그리고 본 연구에서 제안한 전단 연결도(shear connection degree)는 UHPFRC 합성부재의 완전부착과 부분부착에 대한 기준으로 사용될 수 있다.

(A) comparative study on parametric and nonparametric methods of rainfall frequency analyses

이상복 Graduate School, Yonsei University 2004 국내석사

Currently the disasters of climate changes have increased. Frequency analysis has been performed to prevent the disaster that might come from certain climate change. The main purpose of frequency analysis is to estimate quantiles for a given data. In this study, a comparative study was made on parametric and nonparametric methods of frequency analyses of rainfall quantile estimation. The most important thing for frequency analysis is to gather good data. The observation data are based on annual maximum rainfall series at substations in the Korea Methodology Adminstration(KMA). The frequency analysis can be mainly divided into two approaches; parametric and nonparametric methods. First, the method of parametric is to estimate quantiles by using any probability distributions. Second, the nonparametric method is not making the assumption of any distribution, in which quantile is estimated by using kernel density function.In this research, a comparative of analysis is performed to compare quantiles based on parametric and nonparametric methods. For parametric methods, both Gumble and GEV distributions are selected for the appropriate distributions. But the result of goodness-of-fit test shows that the GEV distribution is better than Gumbel one for annual maximum rainfall data. Although quantile estimation of the nonparametric method does not need the assumption of any distribution, the quantiles can be affected by choice of kernel function and bandwidth. As a result, quantile estimation of the nonparameric method is better than that of the parametric method with in interpolation range. On other hand quantile estimation of the nonparametric method can be underestimated in extrapolation. For further investigation, we would be interested more in the semiparametric method. 최근 들어 기후변화에 의한 재해는 지속적으로 증가하고 있는 추세이며, 극치사상에서 수공구조물의 재해 피해는 뚜렷하게 나타나고 있다. 이에 따른 대처방안으로 빈도해석에 따른 적정 수공구조물의 설계이며, 빈도해석의 주요 목적은 주어진 재현기간에 대한 확률강우량을 산정하는 것이다. 본 연구에서는 연최대강우량 자료를 이용하여 빈도해석 방법에 따른 확률강우량을 산정 비교·분석하였다. 빈도해석 수행에 있어 가장 중요한 요소는 양질의 자료 수집이며, 자료의 상태가 양호한 것으로 판단되는 기상청 산하 관측소의 연최대강우량 자료를 이용하였다. 강우 자료의 수문분석은 통계적인 관점에서 매개변수적 방법과 비매개변수적 방법으로 크게 2가지로 구분할 수 있다. 첫째, 매개변수적 방법은 적용 확률분포형의 가정에 따라 확률강우량을 산정하게 된다. 둘째, 비매개변수적 방법은 분포형의 가정 없이 강우량 자료를 핵밀도함수에 적용하여 분포의 특성을 나타냄으로써 확률강우량을 산정하는 방법이다. 본 연구는 연최대강우량 자료에 대한 매개변수 방법과 비매개변수 방법의 확률강우량을 산정하여 비교 분석하였다. 분포형의 가정에 따른 매개변수 방법은 Gumbel, GEV 분포형 등이 적정분포형으로 나타났으며, 적합도 검정 및 확률강우량 산정결과 GEV 분포가 Gumbel 분포보다 좋은 결과를 나타냈다. 비매개변수 방법에 의한 확률강우량 산정은 분포형의 가정없이 적용할수 있다는 장점을 보였으나 핵함수의 선정과 광역폭 선택에 따라 확률강우량의 많은 차이를 보였다. 또한 내삽범위의 확률강우량 산정에 있어 매개변수 방법보다 좋은 결과를 나타냈지만 외삽범위의 확률강우량은 과소추정의 결과를 산출하였다. 차후 빈도해석은 내삽범위의 우수성을 가지는 비매개변수 방법과 외삽범위에 대해 신뢰적인 특성을 갖는 매개변수 방법을 이용한 새로운 방법이 필요한 것으로 판단된다.

Solidification and ultimate disposal options of heavy metal sludge

김종오 Korea Advanced institute of Science and Technology 1990 국내박사

Retrofit prioritization of bridges based on seismic damage risk and failure cost analysis

이상우 Graduate School, Yonsei University 2003 국내박사

지진의 발생빈도가 상대적으로 작고, 지진강도 또한 크지 않은 중·약진지역에서 내진보강이 요구되는 모든 교량구조물에 대해 현행 내진설계수준으로 보강을 수행한다는 것은 매우 비경제적인 일이다. 특히 우리나라와 같이 중·약진의 지진강도가 예상되는 지역에서 한정된 재정자원으로 교량구조물의 내진안전성을 효과적으로 확보하기 위해서는 발생가능한 지진하중에 의한 교량구조물의 손상가능성을 평가하고, 이에 기초하여 내진보강이 요구되는 교량구조물의 우선순위를 결정하는 것이 우선적으로 필요하다. 본 연구에서는 발생가능한 지진하중에 의한 교량구조물의 손상위험도와 손상비용에 근거한 가중치를 이용하여 교량구조물의 내진보강 우선순위를 보다 실제적이고, 명확하게 구분할 수 있으며, 평가된 우선순위에 따라 교량별 내진보강이 요구되는 취약부위를 합리적으로 결정할 수 있는 방법론을 제안하였다. 이를 위하여 교량구조물의 지진거동에 영향을 미치는 중요인자들을 고려할 수 있으며, 다양한 지진취약부위의 손상상태를 평가할 수 있는 단순화된 교량해석모형을 개발하였다. 개발된 교량해석모형을 이용하여 교량구조물의 사용기간동안에 발생가능한 지진하중에 의한 각 지진취약부위의 손상확률을 평가하였다. 또한 각 지진취약부위들간의 상대적 영향이나 교량구조물간의 상대적 중요도를 반영하기 위하여 각 지진취약부위별, 교량별 가중치를 손상으로 인해 교량구조물에 야기되는 총 비용에 근거하여 산정하였다. 최종적으로 교량구조물의 내진보강 우선순위는 교량구조물의 손상위험도와 가중치로부터 구해지는 교량별 순위지수에 근거하여 결정되었으며, 결정된 우선순위에 따른 교량별 내진보강부위는 지진취약부위의 손상확률에 근거하여 선정되었다. 제안된 방법론의 타당성을 검증하기 위하여 본 방법론의 결과가 기존의 방법론에 의한 결과와 비교, 분석되었다. 현행 내진설계기준에 따라 두 방법론에 동일한 조건을 부여하기 위해 인접 진동계간 충돌 및 받침 손상에 따른 영향은 고려되지 않았다. 분석결과, 두 방법론에 의한 결과가 유사한 경향을 갖는 것으로 나타났으며, 특히 본 연구에서 제안한 방법론이 각 교량별 내진보강 우선순위를 보다 명확하게 구분할 수 있는 것으로 평가되었다. 따라서 본 방법론은 교량구조물의 사용기간동안에 발생가능한 지진하중에 의한 지진취약부위의 손상확률과 손상비용에 근거한 가중치를 이용함으로써 교량구조물의 내진보강 우선순위 및 교량별 내진보강이 요구되는 취약부위를 보다 실제적으로 결정할 수 있을 것으로 판단된다. 또한 내진보강에 따른 교량구조물의 우선순위 변화를 분석하기 위하여 우선순위에 따라 내진보강이 요구되는 취약부위가 보강된 교량구조물의 우선순위를 재평가하였다. 평가결과로부터 내진 보강된 교량구조물의 순위지수가 내진보강이 요구되지 않는 교량구조물보다도 상당히 낮은 것으로 분석되었다. 따라서 본 연구에서 제안된 방법론은 기존의 방법론과는 달리 기존교량이나 신설교량은 물론 내진 보강된 교량구조물에 대한 우선순위를 효과적으로 평가할 수 있으며, 보강된 교량구조물의 순위지수 변화를 통하여 교량구조물의 내진보강에 따른 내진성능 향상효과도 간접적으로 평가될 수 있을 것으로 판단된다. A seismic damage risk and failure cost based methodology is developed to determine the priority of bridges in need of seismic retrofit. The validity of the developed methodology is verified in comparison with the results of the existing methodology in current practice. The retrofit priority of selected model bridges is estimated using the developed methodology. The ranking indices of the model bridges retrofitted according to the retrofit priority are revaluated. To determine the retrofit priority efficiently, a simulation procedure is developed by using a simplified mechanical bridge model. The bridge model can consider the damage states of various vulnerable components as well as various phenomena involved in the realistic seismic behaviors of girder-type bridges. The seismic damage risk of bridges is evaluated in the probabilistic perspectives using the simplified bridge model. Based on the failure cost of structural components and bridges, weighting factors are determined. The weighting factors reflect the relative effect and importance of vulnerable components as well as bridge systems. The ranking indices of bridges are evaluated using the overall damage risk and weighting factors. At the final stage, the vulnerable components in need of seismic retrofit are selected accordingly. The retrofit priority of model bridges is determined and compared with that of the existing methodology in current practice. The results show the similar trends in both methodologies, confirming the validity of the developed methodology. In addition, the developed methodology can reveal the priority in more detail that cannot be determined from the existing methodology because the damage risk and the weighting factors are reasonably considered. Consequently, the developed methodology can give more realistic results in determining the priority of bridges for seismic retrofit. The ranking indices of the model bridges retrofitted according to the retrofit priority are revaluated. Based on the simulated results of existing and retrofitted bridges, the application of retrofitting method is found to be either positive or negative in some cases. Therefore, the retrofitting method of existing bridges should be carefully selected based on the results of detailed seismic analysis of bridges. Consequently, the seismic damage risk and failure cost based methodology developed in this study can be effectively used in evaluating the retrofit priority of the existing and retrofitted bridges as well as in analyzing the retrofitting effects of the existing bridges.