Analysis of Deep Foundation Behavior Using Fiber Optical Sensor

다국어 초록 (Multilingual Abstract)

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.

목차 (Table of Contents)

• Abstract = ⅰ
• Table of Contents
• List of Figures = 1
• 1 Introduction = 1
• 1.1 Background = 1
• 1.2 Problems in Deep Foundation Engineering = 3
• 1.3 Research Methods = 4
• 1.4 Study Objectives = 5
• 1.5 Thesis Structure = 5
• 2 Distributed Sensing Principle And Instrumentation = 7
• 2.1 BTODR Principle = 7
• 2.2 Physical Aspects = 10
• 2.3 Demands for Strain Monitoring of Civil Structure = 13
• 2.4 BOTDR Instrument = 16
• 3 Experimental Investigation of BOTDR Distributed Sensing = 19
• 3.1 Theory Basis = 19
• 3.2 Pole Moving Test = 22
• 3.3 PVC Pipe Loading Test And Cantilever Test = 24
• 3.4 10m Aluminium Pipe Deformation Expriment = 28
• 4 Project Description & Data Analysis = 32
• 4.1 Introduction = 32
• 4.2 Pusan Meongji Site = 33
• 4.3 Optical Fiber Cable Topology = 34
• 4.4 Optical Fiber Configuration in Pile = 35
• 4.5 Sensors Configuration = 38
• 4.6 Bare Fiber Installation = 38
• 4.6.1 Driving procedure = 40
• 4.6.2 Data analysis = 42
• 4.6.3 Setup period = 53
• 4.6.4 Static Loading Test = 65
• 4.7 Comparison of Results from FOS and Strain Gauge = 66
• 4.8 Incheon Site = 70
• 4.9 Optical Fiber Cable Design = 71
• 4.10 Optical Fiber cable topology = 73
• 4.11 Static Loading Test = 75
• 4.12 Static Loading Data Analysis = 76
• 5 Conclusion & Future Work = 78
• 5.1 Concluding Remarks = 78
• 5.2 Improvement about Pile and FOS Interface = 79
• Bibliography = 79
• AcknowIedgements = 81