Smart Impedance Monitoring Technique for Multi-strands Anchorage in Prestressed Concrete Structures
- Alternative Title
- 프리스트레스 콘크리트 구조물 멀티스트랜드 정착부의 스마트 임피던스 모니터링 기술
- Abstract
- The objective of this dissertation is to develop a smart impedance monitoring technique for multi-strands anchorage in prestressed concrete (PSC) structures. To achieve the objective, firstly, fundamentals of impedance-based damage detection methods are presented. Secondly, local stress analysis of a prestressed multi-strands anchorage is numerically and experimentally conducted to determine the damage-sensitive impedance sensor placement. Thirdly, the feasibility of a smart PZT (lead-zirconate-titanate) interface-based impedance measurement for monitoring local strand breakage in a prestressed multi-strands anchorage is numerically investigated. Fourthly, real-scale experiments on prestressed multi-strands anchorages are conducted to determine optimal impedance sensor placement. Also, the feasibility of the hoop-type PZT interfaces is evaluated for monitoring local strand breakage. Fifthly, the applicability of the PZT interface technique is numerically and experimentally analyzed for strand breakage detection in a concrete anchorage of a PSC structure. Sixthly, filtering temperature effects on impedance features via PZT interfaces is experimentally investigated. Lastly, a parametric study is conducted to analyze the effects of the PZT interface’s material and geometry on impedance monitoring. The result shows that the smart PZT interface technique is promising for monitoring multi-strands anchorage in PSC structures.
본 논문의 목적은 프리스트레스 콘크리트(PSC) 구조물의 텐던 파손 및 긴장력 감소를 탐지하기 위한 멀티스트랜드(multi-strands) 정착부의 임피던스 기반 모니터링 기술을 개발하는 것이다. 연구 목표를 달성하기 위해, 먼저 임피던스 기반 손상 감지 기법의 기본 사항을 제시하였다. 둘째, 손상에 민감한 임피던스 센서 배치를 결정하기 위해 수치실험을 통해 프리스트레스 멀티스트랜드 정착부의 국부응력을 분석하였다. 셋째, 멀티스트랜드 정착부에서 강연선의 국부 파손을 모니터링하기 위해 스마트 PZT (lead-zirconate-titanate) 인터페이스 기반의 임피던스 측정의 타당성을 분석하였다. 넷째, 모형 실험을 통해 최적의 임피던스 센서 배치를 결정하고 로컬 스트랜드 파손을 모니터링하기 위한 후프 타입 PZT 인터페이스의 타당성을 평가하였다. 다섯째, PSC 구조의 콘크리트 앵커리지에서 강연선 파손 탐지를 위한 PZT 인터페이스 기술의 적용을 수치적으로 분석하였다. 여섯째, PZT 인터페이스의 임피던스 특성에 대한 온도 영향 분석 및 보정 기법을 실험적으로 분석하였다. 마지막으로, PZT 인터페이스의 재료 및 형상이 임피던스 모니터링에 미치는 영향을 분석하기 위한 변수 해석을 수행하였다. 실험결과로부터, 스마트 PZT 인터페이스 기술이 PSC 구조물의 멀티스트랜드 정착부를 모니터링하는데 매우 유용한 기술임을 입증하였다.
- Issued Date
- 2020
- Awarded Date
- 2020. 8
- Type
- Dissertation
- Publisher
- 부경대학교
- Affiliation
- Pukyong National university, Graduate school
- Department
- 대학원 해양공학과
- Advisor
- Jeong-Tae Kim
- Table Of Contents
- CHAPTER 1 INTRODUCTION 1
1.1 Overview 1
1.2 Structural Health Monitoring of PSC Structures 3
1.2.1 Existing Monitoring Technique 3
1.2.2 Impedance-based Methods 5
1.3 Research Needs on Multi-strands Anchorage of PSC Structures 11
1.4 Objective and Approach 13
1.5 Organization of Thesis 14
CHAPTER 2 FUNDAMENTALS OF IMPEDANCE-BASED DAMAGE DETECTION TECHNIQUE 17
2.1 Overview 17
2.2 Piezoelectric Sensors and Actuators for Structural Health Monitoring 17
2.3 Impedance-based Damage Detection Methods 19
2.3.1 Fundamental of Impedance-based Method 19
2.3.2 Effective Frequency Bands for Impedance Monitoring 21
2.3.3 PZT Interface Technique for Impedance Monitoring 22
2.3.4 Statistical Damage Quantification of Impedance Responses 24
CHAPTER 3 DAMAGE-SENSITIVE IMPEDANCE SENSOR PLACEMENT ON MULTI-STRANDS ANCHORAGE BASED ON LOCAL STRESS VARIATION ANALYSIS 27
3.1 Overview 27
3.2 Analysis of Stress Fields in Multi-strands Anchorage 27
3.2.1 FE Model of Multi-strands Anchorage 27
3.2.2 Variation of Stress Fields due to Local Strand Breakage 30
3.2.3 Selection of Contact Stiffness for Simulating a Concrete Block 34
3.3 Experimental Stress Analysis on Multi-strands Anchorage 35
3.3.1 Test Set-up 35
3.3.2 Experimental Strain Responses of Multi-strands Anchorage 42
3.3.3 Experimental Stress Variation Induced by Strand Breakage 46
3.3.4 Discussion on Measured Stress Variation Induced by Strand Breakage 50
3.4 Damage-Sensitive Structural Model of Multi-strands Anchorage 51
3.5 Summary and Remarks 52
CHAPTER 4 HOOP-TYPE PZT INTERFACE FOR LOCAL STRAND-BREAKAGE DETECTION IN MULTI-STRANDS ANCHORAGE 54
4.1 Overview 54
4.2 Hoop-type PZT Interface for Impedance Measurement in Prestressed Multi-strands Anchorage 55
4.3 Design of Hoop-type PZT Interface for Multi-strands Anchorage 58
4.3.1 Prototype Design of Hoop-type PZT Interface 58
4.3.2 Dynamic Characteristics of Hoop-type PZT Interface 60
4.4 Numerical Evaluation of Hoop-type PZT Interface for Strand Breakage Detection 63
4.4.1 FE Model of Multi-strands Anchorage with Hoop-type PZT Interface 63
4.4.2 Numerical Impedance Responses of Hoop-type PZT Interface 64
4.4.3 Linear Tomography of RMSD Index for Localization of Damaged Strands 71
4.5 Preliminary Feasibility Test of Hoop-type PZT Interface for Impedance-based Stress Variation Monitoring 76
4.5.1 Experimental Set-up 76
4.5.2 Impedance-based Stress Change Monitoring Result 77
4.6 Summary and Remarks 80
CHAPTER 5 EXPERIMENTAL EVALUATION OF PZT INTERFACE FOR STRAND BREAKAGE DETECTION IN MULTI-STRANDS ANCHORAGE 82
5.1 Overview 82
5.2 Optimal Sensor Locations for Impedance Monitoring 82
5.2.1 Experimental Set-up 82
5.2.2 Sensitivity of Impedance Responses under Strand Breakage Cases 85
5.3 Experimental Evaluation of Hoop-type PZT Interface for Local Strand-Breakage Detection in Multi-strands Anchorage 88
5.3.1 Experimental Set-up and Test Scenarios 88
5.3.2 Impedance Responses of PZT Interface under Local Strand Breakage 91
5.3.3 Strand Breakage Detection using Impedance Features 95
5.4 Summary and Remarks 102
CHAPTER 6 APPLICATION OF PZT INTERFACE TECHNIQUE FOR STRAND BREAKAGE DETECTION IN PRESTRESSED CONCRETE STRUCTURE 103
6.1 Overview 103
6.2 Numerical Evaluation of Hoop-type PZT Interface for Monitoring Strand Breakage in Multi-strands Concrete Anchorage 103
6.2.1 FE Model of Multi-strands Concrete Anchorage with PZT Interfaces 103
6.2.2 Strand Breakage Localization using Numerical Impedance Features 108
6.3 Experimental Verification of Hoop-type PZT Interface for Strand Breakage Localization in PSC Anchorage 111
6.3.1 Test Set-up and Test Scenarios 111
6.3.2 Impedance Responses of PZT Interfaces Measured from Prestressed Concrete Anchorage under Strand Breakage 112
6.3.3 Strand Breakage Localization in PSC Anchorage using Impedance Features 115
6.4 Discussion on Effects of Concrete Anchorage on Impedance Responses 120
6.5 Summary and Remarks 124
CHAPTER 7 FILTERING TEMPERATURE EFFECTS ON IMPEDANCE FEATURES FOR STRAND BREAKAGE DETECTION IN PRESTRESSED CONCRETE ANCHORAGE 125
7.1 Overview 125
7.2 Numerical Analysis of Effects of Temperature Variation on Impedance Responses in PSC Anchorage 125
7.2.1 FE Model and Simulation Cases 125
7.2.2 Sensitivity of Impedance Responses under Strand Breakage and Temperature Variation 127
7.3 Temperature-Effects Compensation Methods 131
7.3.1 PCA-based Method 131
7.3.2 EFS-based Method 132
7.4 Experiments on Prestressed Concrete Anchorage 134
7.4.1 Test Set-up 134
7.4.2 Performance of Temperature Variation and Strand Breakage Cases 136
7.5 Impedance Monitoring in PSC Anchorage at Near-constant Temperature 138
7.5.1 Impedance Responses of PZT Sensors under Strand Breakage 138
7.5.2 Strand Breakage Detection at Near-constant Temperature 140
7.6 Effects of Temperature Variation on Impedance Signatures Measured via Hoop-type PZT Interfaces 141
7.6.1 Effects of Temperature Variation on Impedance Responses 141
7.6.2 Strand Breakage Monitoring without Temperature-Effect Compensation 144
7.7 Filtering Temperature Effects on Impedance Features for Strand Breakage Detection 146
7.7.1 PCA-based Temperature Compensation 146
7.7.2 EFS-based Temperature Compensation 161
7.8 Summary and Remarks 170
CHAPTER 8 EFFECTS OF PZT INTERFACE’S MATERIAL AND GEOMETRY ON DAMAGE-SENSITIVE IMPEDANCE RESPONSE 172
8.1 Overview 172
8.2 FE Model and Simulation Scenarios 172
8.2.1 FE Model 172
8.2.2 Simulation Scenarios 173
8.3 Effects of Interface’s Material on Damage-Sensitive Impedance Responses 177
8.4 Effects of PZT Interface’s Geometry on Damage-Sensitive Impedance Responses 179
8.4.1 Effects of Interface’s Geometry 179
8.4.2 Effects of PZT’s Geometry 185
8.5 Experimental Evaluation of PZT Interface’s Material and Geometry Effects on Impedance Monitoring 188
8.5.1 Test Set-up and Test Scenarios 188
8.5.2 Experimental Result of Interface’s Material Effects 191
8.5.3 Experimental Result of PZT Interface’s Geometry Effects 192
8.6 Summary and Remarks 196
CHAPTER 9 SUMMARY AND CONCLUSION 197
REFERENCES 199
CURRICULUM VITAE 209
ACKNOWLEDGMENTS 214
- Degree
- Doctor
- Files in This Item:
-
-
Download
Smart Impedance Monitoring Technique for Multi-strands Anchorage in Prestressed Concrete Structures.pdf
기타 데이터 / 13.02 MB / Adobe PDF
-
Items in Repository are protected by copyright, with all rights reserved, unless otherwise indicated.