A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Distributed Fiber Optic Sensing of Helical Pile Loads in Pile-Reinforced Rail Applications
Localized areas of weak subgrade under rail tracks can lead to increased damage to the rail and rail sleepers, and rapid deterioration of the trackbed geometry requiring frequent maintenance. One solution to mitigate this problem is the installation of piles under the rail in the ballast, which would then allow for the loads from the tracks to bypass any low stiffness subgrade materials. However, there are uncertainties regarding the distribution of loads in this system, which require improved measurements of pile behaviour to understand. The objectives of this thesis are to a) develop a technique for measuring axial load and bending along the full length of helical piles, and b) use these measurements to understand the load distribution in a pile-reinforced rail foundation. To protect the distributed fibre optic sensors during pile installation, a PVC insert method was adopted, whereby a series of distributed fibre optic strain sensors were installed on a PVC pipe, which was then placed inside a steel helical pile, and the two were epoxied together. The strain measurements were then used to calculate both the axial loading and bending along the length of the pile. Four prototypes were constructed to examine the impact of pile diameter and fibre type, and in-air eccentric axial load testing was completed. The strain measurements from the PVC inserts were in good agreement with strain measurements from fibres mounted to the outside of the pile. A fullscale laboratory test setup involving a single railway tie supported by four helical piles was used to investigate the impact of ballast depth on pile load. Four load tests were completed on the system at ballast depths of 900, 635, and 350 mm, with three of the tests having three cycles up to 50 kN applied, and the final test having one cycle up to 90 kN. The response of the system during the loading was monitored using the developed PVC insert sensor system and a series of settlement plates. The distributed measurements of axial and bending moment showed a ...
Distributed Fiber Optic Sensing of Helical Pile Loads in Pile-Reinforced Rail Applications
Localized areas of weak subgrade under rail tracks can lead to increased damage to the rail and rail sleepers, and rapid deterioration of the trackbed geometry requiring frequent maintenance. One solution to mitigate this problem is the installation of piles under the rail in the ballast, which would then allow for the loads from the tracks to bypass any low stiffness subgrade materials. However, there are uncertainties regarding the distribution of loads in this system, which require improved measurements of pile behaviour to understand. The objectives of this thesis are to a) develop a technique for measuring axial load and bending along the full length of helical piles, and b) use these measurements to understand the load distribution in a pile-reinforced rail foundation. To protect the distributed fibre optic sensors during pile installation, a PVC insert method was adopted, whereby a series of distributed fibre optic strain sensors were installed on a PVC pipe, which was then placed inside a steel helical pile, and the two were epoxied together. The strain measurements were then used to calculate both the axial loading and bending along the length of the pile. Four prototypes were constructed to examine the impact of pile diameter and fibre type, and in-air eccentric axial load testing was completed. The strain measurements from the PVC inserts were in good agreement with strain measurements from fibres mounted to the outside of the pile. A fullscale laboratory test setup involving a single railway tie supported by four helical piles was used to investigate the impact of ballast depth on pile load. Four load tests were completed on the system at ballast depths of 900, 635, and 350 mm, with three of the tests having three cycles up to 50 kN applied, and the final test having one cycle up to 90 kN. The response of the system during the loading was monitored using the developed PVC insert sensor system and a series of settlement plates. The distributed measurements of axial and bending moment showed a ...
Distributed Fiber Optic Sensing of Helical Pile Loads in Pile-Reinforced Rail Applications
Sherlock, Sam (author) / Civil Engineering / Take, Andy / Hoult, Neil
2022-11-01
Theses
Electronic Resource
English
Distributed Fiber Optic Sensing in Pile Load Tests: Technological Development and Applications
| Springer Verlag | 2022
Distributed Fiber-Optic Strain Sensing: Field Applications in Pile Foundations and Concrete Beams
| Springer Verlag | 2021