헤테로코어 광섬유 센서를 이용한 PSC 거더의 프리스트레스 측정용 쉬스관 일체형 센서모듈의 개발
- Alternative Title
- A Sheath-combined Sensor Module for Measuring Prestress of PSC Girders Using Hetero-core Optical Fiber Sensor
- Abstract
- Prestressed concrete (PSC) is extensively used in the construction sector, including in long-span bridges, high-rise buildings, and nuclear power plants, due to its exceptional structural performance. PSC is particularly beneficial because it effectively mitigates the degradation of structures resulting from recurring issues in reinforced concrete, such as the corrosion of reinforcing steel and the formation of cracks.
According to the road, bridge, and tunnel statistics published by the Ministry of Land, Infrastructure, and Transport, PSC bridges constitute 54.6% of all short to mid-span bridges (with spans of 20-50m) in Korea as of 2022. As such, they surpass steel bridges and reinforced concrete bridges in prevalence, making them the most common type of bridge.
However, the number of outdated PSC bridges requiring rigorous monitoring for facility management is on the rise. 24.2% of short to mid-span PSC bridges have already exceeded a service life of 20 years. Over the next decade, the number of bridges surpassing 30 years of service life is expected to exponentially increase, necessitating inspections for potential repair or reconstruction. Therefore, the urgent implementation of effective management measures for aging PSC bridges is crucial.
The goal of this study was to develop a sensor module by employing a hetero-core optical fiber sensor, which quantitatively evaluate prestress in response to the structural displacement.
In a hetero-core optical fiber sensor, the intensity of light that passes through the optical fiber varies linearly in response to changes in curvature of any specific part. This linear change, when correlated with external displacement, allows the sensor to function as a dynamic sensor. With this principle and previous instances of sensor development, a sheath-combined sensor module capable of being embedded within a PSC structure was fabricated.
In order to assess the response performance of the sensor module to displacement, three tests were conducted: an exposure state performance test in the first step, an embedded state performance test in the second, and a PSC beam application test in the third step.
In the first and second steps of the performance experiment, the coefficient of determination (R-squared) was calculated between the displacement of the sensor module and the power of the light passing through the optical fiber. The results revealed a high degree of correlation, with an R-squared value between 0.88 and 0.99. This suggests that the proposed sensor can be effectively employed as a dynamic sensor due to the strong correlation between the sensor module and optical fiber for external displacement.
In the third step of the performance experiment, the sensor module was installed on the sheath pipe of a PSC beam specimen. Then the sensor module's response was measured by inducing prestress in the specimen using a center point loading method. Additionally, strain gauges were attached to the reinforcing steel and concrete, and a linear variable displacement transducer (LVDT) was installed on the specimen to measure the resulting strain and deflection. The performance of the sensor module was verified by comparing its response to these measurement results.
In the third step of the performance experiment, the R-squared value between the strain and power of the specimen was calculated to be 0.971, thus demonstrating a high degree of correlation. The regression equation was defined as 'Strain = 6.529 × nWatt - 895.422'. To verify this regression equation, a paired t-test was conducted, and the resulting R-squared value between the measured and calculated values was 0.967, indicating excellent applicability for the regression equation.
Through performance experiments, this study confirmed the capability of the developed sheath-combined sensor module to measure prestress based on its response to displacement in PSC structures. This suggests the potential for commercializing the sensor module to effectively manage the prestress of PSC bridges.
- Issued Date
- 2023
- Awarded Date
- 2023-08
- Type
- Dissertation
- Publisher
- 부경대학교
- Alternative Author(s)
- Hee-Won Yang
- Affiliation
- 부경대학교 대학원
- Department
- 대학원 토목공학과
- Advisor
- 이환우
- Table Of Contents
- 1. 서론 1
1.1. 연구 배경 1
1.2. 연구의 필요성 6
1.2.1. 차세대 PSC 거더용 신기술 개발의 필요성 6
1.2.2. 연구 동향 8
1.3. 연구의 목표 및 내용 10
2. 광섬유 센서 일반 사항 14
2.1. 개요 14
2.2. 광섬유 센서의 종류 16
2.2.1. 측정 범위에 따른 분류 16
2.2.2. 측정 방식에 따른 분류 17
2.3. 광섬유 센서의 비교 33
3. 쉬스관 일체형 센서 모듈 개발 38
3.1. 개요 38
3.2. 센서 모듈 사례 조사 40
3.3. 센서 모듈 제작 이력 46
3.3.1. 노출형 센서 모듈 46
3.3.2. 매립형 센서 모듈 50
3.3.3. 쉬스관 일체형 센서 모듈 56
3.4. 쉬스관 일체형 센서 모듈의 제작 59
3.4.1. 센서 모듈이 갖추어야 할 성능 59
3.4.2. 센서 모듈 제작을 위한 세부 검토 사항 61
3.4.3. 쉬스관 일체형 센서 모듈 70
4. 노출 상태 성능 확인 75
4.1. 센서 모듈 성능 확인 개요 75
4.2. 전동 변위 스테이지를 이용한 확인 실험 78
4.2.1. 개요 78
4.2.2. 실험 장비 78
4.2.3. 실험 방법 82
4.2.4. 실험 결과 84
4.3. 만능 재료 시험기를 이용한 확인 실험 95
4.3.1. 개요 95
4.3.2. 실험 장비 95
4.3.3. 실험 방법 98
4.3.4. 실험 결과 99
4.4. 실험 결과 분석 103
5. 매립 상태 성능 확인 105
5.1. 실험 개요 105
5.2. 실험 장비 106
5.3. 실험 방법 107
5.3.1. 시험체 제작 107
5.3.2. 매립 상태 실험 방법 111
5.4. 실험 결과 115
6. PSC 보 시험체를 이용한 센서 모듈 성능 확인 123
6.1. 실험 개요 123
6.2. PSC 보 시험체 설계 및 제작 125
6.2.1. 시험체 설계 125
6.2.2. 시험체 제작 129
6.2.3. 계측 센서 설치 133
6.3. 긴장력 도입에 대한 센서의 응답 특성 확인 실험 140
6.3.1. 실험 개요 140
6.3.2. 실험 장비 141
6.3.3. 실험 방법 146
6.3.4. 실험 결과 및 분석 148
6.4. 휨에 대한 센서의 응답 특성 확인 실험 160
6.4.1. 실험 개요 160
6.4.2. 실험 장비 161
6.4.3. 실험 방법 163
6.4.4. 실험 결과 및 분석 167
6.5. 센서 모듈 실험 검증 183
6.5.1. 전력량과 변형률 간 상관 분석 183
6.5.2. 전력량과 변형률 간 회귀 분석 185
6.5.3. 회귀식 도출 189
6.5.4. 회귀식 검증 190
7. 결론 193
참고문헌 197
- Degree
- Doctor
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헤테로코어 광섬유 센서를 이용한 PSC 거더의 프리스트레스 측정용 쉬스관 일체형 센서모듈의 개발.pdf
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