• 한국구조물진단유지관리공학회 논문집
• /
• 제8권4호
• /
• pp.185-193
• /
• 2004

현재의 교량의 유지관리 시에 적절한 보수 시기나 최적화된 유지관리 정책을 결정하기 위하여 교량의 성능저하를 정확히 예측하는 것은 가장 중요한 일이다 이률 위해 제안된 방법은 정량적 평가, 마르코프체인, 베이시안 추정법 등으로 구성되었다. 제안된 방법에 따라 국내의 콘크리트 슬래브 교량을 예로서 예측을 하여는데, 기존의 전문가 의견조사 빛 외관조사에 의한 예측보다 좀 더 합리적인 결과를 보여주었다.

• 한국구조물진단유지관리공학회 논문집
• /
• 제25권1호
• /
• pp.75-84
• /
• 2021

본 연구에서는 강교량용 일반중방식 도장계열의 신설 도장계 및 재도장계의 내구수명 예측과 도막 열화곡선을 검토하기 위하여 표면처리방법과 도장 종류를 변수로 총 12종류의 도장 시험편에 대하여 실내 부식촉진시험을 실시하였다. 표면처리는 신설(공장도장)과 재도장(현장도장)에 따라 수공구 (SSPC SP-2), 동력공구 (SP-3), 블라스트 처리(SP-10)를 적용하였다. 도장 시험편은 ISO 20340 부식환경 조건에서 실시하였으며, 각 도장계별 열화곡선은 초기결함으로부터 발생된 부풂 및 녹 면적을 기준으로 평가되었다. 또한 대기 부식성 범주와 강재 내구 성능평가 기준을 이용하여 신설 및 보수 도장계의 내구수명을 실험적으로 평가하였다. 그 결과 표면처리 방법에 따른 신설 도장계와 재도장계의 내구수명을 정량적으로 평가하였으며, 대기부식성 등급 C4에서 일반중방식 신설 도장계의 내구수명은 18 ~ 21년, 재도장계는 5.3 ~ 8.0년으로 추정된다.

• 한국주거학회논문집
• /
• 제20권6호
• /
• pp.89-99
• /
• 2009

The purpose of this research is to determine the deterioration characteristics of high-rise and high-density apartment complexes in 1st period new towns in order to regenerate apartments as sustainable residential environments in Korea. For this purpose, the level of deterioration was evaluated by using 'evaluating indicators of the level of deterioration of high-rise and high-density apartments'. The deterioration characteristics were determined inclusively and concretely based on evaluation results. In addition, the deterioration level according to residents' awareness of the deterioration of their apartment was evaluated. This study was conducted by methods of field data collection, staff interview, field measurement, and resident survey according to the measurement of the evaluating indicators. And the re-organized questionnaire based on the evaluating indicators was utilized for a survey of resident's awareness. The results are as follows: In the physical dimensions of apartments, the deterioration characteristics included deteriorated equipment and a decline in structural performance due to the aging of the apartment, a shortage of parking spaces, and the low flexibility of the bearing wall structure, etc. In terms of the social dimensions, the apartments showed an increase in the number of elderly households, a shortage of community facilities, and a lack of the opportunity for community participation etc. In terms of the economic dimensions, the apartments showed limitations in maintenance & repair and a lack of environmentally friendly features.

• Earthquakes and Structures
• /
• 제24권5호
• /
• pp.333-343
• /
• 2023

Various seismic isolation and reduction devices have been applied to suppress the longitudinal vibration of continuous girder bridges. As representative devices, lead rubber bearing (LRB) and fluid viscous damper (FVD) might suffer from deterioration during the long-term service. This study aims to evaluate the impact of device deterioration on the seismic responses of continuous girder bridges and investigate the seismic behavior of deteriorated LRBs and FVDs. Seismic performance of a simplified bridge model was investigated, and the influence of device deterioration was evaluated by the coefficient of variation method. The contribution of LRB and FVD was assessed by the Sobol global sensitivity analysis method. Finally, the seismic behaviors of deteriorated LRBs and FVDs were discussed. The result shows that (i) the girder-pier relative displacement is the most sensitive to the changes in the deterioration level, (ii) the deterioration of FVD has a greater effect on the structural responses than that of LRB, (iii) FVD plays a major role in energy dissipation with a low degradation level while LRB is more essential in dissipating energy when suffering from high degradation level, (iv) the deteriorated devices are more likely to reach the ultimate state and thus be damaged.

• Structural Engineering and Mechanics
• /
• 제3권4호
• /
• pp.341-358
• /
• 1995

The results of a series of ten W-shaped test specimens subjected to monotonic, quasi-static cyclic loading and fatigue type of loading in the form of constant amplitude tests are presented. The objectives were to assess and compare the rotation capacity and energy absorption of monotonically and cyclically loaded beams, and for the latter specimens to document the deterioration in the form of low cycle fatigue due to local buckling. In addition, strength and energy dissipation deterioration and damage models have been developed for the steel beam section under consideration. Finally, a generalized model which uses plate slenderness values and lateral slenderness is proposed for predicting rate in strength deterioration per reversal and cumulated damage after a given number of reversals.

• 한국구조물진단유지관리공학회 논문집
• /
• 제14권2호
• /
• pp.171-175
• /
• 2010

본 연구는 동결융해, 염해 및 중성화가 복합적으로 작용하는 콘크리트 구조물의 내구성능을 평가하기 위하여 일반강도 콘크리트를 대상으로 동결수를 달리하여 동결융해 시험을 실시함으로서 염해와 동결융해 복합작용에 의한 콘크리트의 열화를 평가하였고, 염해, 동결융해 및 중성화의 세가지 열화가 복합적으로 발생되는 복합열화에 대해서는 적절한 평가방법이 부재하여 동결수에 따른 동결융해 시험 후의 시험체에 대하여 중성화 촉진시험을 실시함으로서 복합열화에 의한 콘크리트 내구성능 저하 특성을 평가하고자 하였다. 본 연구를 통하여 동결수의 종류나 물-결합재비 수준과 무관하게 고로슬래그미분말을 사용한 배합의 경우 염해와 동결융해가 동시에 복합적으로 발생되는 환경에서도 우수한 저항성능을 보이는 결과를 나타내므로 동결융해를 포함한 복합열화 환경에서 충분한 내구성 확보를 위해서는 최소한의 설계기준강도의 확보와 고로슬래그미분말 등 적절한 시멘트 결합재의 선정이 무엇보다 중요하다는 결론을 얻었다.

• 한국구조물진단유지관리공학회 논문집
• /
• 제20권4호
• /
• pp.77-83
• /
• 2016

근래에 송전철탑의 수명연장과 유지관리 비용 절감을 위한 관심이 증가하고 있다. 그러나 송전철탑 부재의 부식 열화도를 진단하는 재래적인 방법으로서 육안점검은 점검자 개인의 지식과 경험의 차이에 따라 오류를 야기하는 문제점을 내포하고 있다. 이러한 문제를 해결하기 위하여, 본 연구에서는 송전철탑 강 부재에 대한 부식열화 검사장비를 개발하였다. 개발된 검사장비는 부식열화 영상 촬영장치 및 컴퓨터 기반 진단 시스템으로 구성된다. 영상처리에 적합한 열화영상을 확보하기 위하여 촬영장치를 개발하여 촬영방법을 표준화하였으며, 진단 시스템은 RGB 컬러영상처리 기법에 기초하여 송전철탑 부재의 부식 열화도를 자동적으로 평가하도록 설계하였다. 개발된 부식열화 검사장비는 송전철탑 부식에 대한 최적 유지보수 시기를 결정하는 것에 도움이 될 것으로 기대된다.

• 상하수도학회지
• /
• 제24권2호
• /
• pp.183-193
• /
• 2010

Well planned rehabilitation order of pipes is essential for efficient maintenance and management of Water Distribution Systems. In this study, not only deterioration rate of pipes but also structural and nonstructural failure which causes abnormal condition of WDS is considered to determine rehabilitation order. Probabilistic Neural Network is used for calculating deterioration rate at present and the importance of pipes is computed under structural and nonstructural failure by using Pipe by Pipe Failure Analysis and Effect Index. Utopian Approach, one of the Multi-Criteria Decision Making methods, is used for assessment of final rehabilitation order based on distance measure between utopian point and alternative one. Developed model in this study shows that it gives more reliable results than existing methods considering hydraulic relative importance does in application to real networks. In this point, the newly developed model, which gives advantages over existing models, can make a credible decision and simple application.

• 콘크리트학회논문집
• /
• 제15권6호
• /
• pp.924-929
• /
• 2003

A majority of infrastructures has been deteriorated over time. Therefore, it is very important to verify the quality of construction, and the level of structural deterioration in existing structures, to ensure their safety and functionality. Many researchers have studied non-destructive testing (NDT) methods to identify structural problems in existing structures. The impact echo technique is one of the widely used NDT techniques. The impact echo technique has several inherent problems, including the difficulties in P-wave velocity evaluation due to inhomogeneous concrete properties, deterioration of evaluation accuracy where multiple reflection boundaries exist, and the influence of the receiver location in evaluating the thickness of the tested structures. Therefore, the objective of this paper is to propose an enhanced impact echo technique that can reduce the aforementioned problems and develop a Virtual Instrument for the application via a thickness evaluation technique which has same technical background to find deterioration in concrete structures. In the proposed impact echo technique, transfer function from dual channel system analysis is used, and coherence is improved to achieve reliable data. Also an averaged signal -ensemble- is used to achieve more reliable results. From the analysis of transfer function, the thickness is effectively identified.

• 한국구조물진단유지관리공학회 논문집
• /
• 제2권4호
• /
• pp.186-193
• /
• 1998

The purpose of this research is to seek properties of flowing light-weight aggregate concrete and possibility of application. The experimental analysis results by using light-weight aggregate and industrial waste such flyash, furnace slag are as follow. 1) The research shows that flowing light-weight aggregate concrete of slump 23~27cm, slump flow 58~69 cm is possible, but material segregation is appeared above slump 26.5cm and slump flow 65 cm. 2) If mixing ratio of flyash is increase, strength deterioration is about 25 % in early age. It showed that effectiveness of long time strength improvement because strength manifestation ratio is above 95% in a long term. 3) This research showed possibility of substitution of blast furnace slag because strength deterioration by using mixing of furnace slag was appeared small deterioration range as below 10 %. 4) Each experimental compressive strength ratios were 77 %(1st week), 86 %(2nd week), 109 %(8th week), 115 %(13th week), 125 % (26th week) on the basis of 28 days. If mixing ratio of flyash is increase, long term strength increase ratio is improved.