Author Contributions
Conceptualization, Y.L. and H.A.-N.; Data curation, Z.S.; Formal analysis, H.A.S.; Funding acquisition, Y.L.; Investigation, H.A.S.; Methodology, H.A.-N.; Resources, Z.S.; Software, H.A.S.; Supervision, Y.L. and H.A.-N.; Validation, H.A.S.; Writing—original draft, Y.L. and H.A.S.; Writing—review & editing, H.A.-N. and Z.S. All authors have read and agreed to the published version of the manuscript.
Figure 1.
Illustration and dimensions of the setup tested in the laboratory connected to the GDS controller and computer (not to scale).
Figure 1.
Illustration and dimensions of the setup tested in the laboratory connected to the GDS controller and computer (not to scale).
Figure 2.
Geometry of the top plates for the axial and lateral loading test (not to scale). (a) Top plate for axial loading; (b) top plate used for lateral loading.
Figure 2.
Geometry of the top plates for the axial and lateral loading test (not to scale). (a) Top plate for axial loading; (b) top plate used for lateral loading.
Figure 3.
Profile of the pressure chamber tested under the axial load (not to scale).
Figure 3.
Profile of the pressure chamber tested under the axial load (not to scale).
Figure 4.
Profile of the pressure chamber tested the under lateral load (a), enlarged drawing of lateral loading setup (b), and actual profile of the test condition (c).
Figure 4.
Profile of the pressure chamber tested the under lateral load (a), enlarged drawing of lateral loading setup (b), and actual profile of the test condition (c).
Figure 5.
Particle size distribution of the Congleton sand.
Figure 5.
Particle size distribution of the Congleton sand.
Figure 6.
Raining method in order to prepare a uniform distribution of the sand in the cell (not to scale).
Figure 6.
Raining method in order to prepare a uniform distribution of the sand in the cell (not to scale).
Figure 7.
FRP preparation steps in the pressure chamber.
Figure 7.
FRP preparation steps in the pressure chamber.
Figure 8.
Effect of surface roughness under an axial load (a) and effect of loading rate on CFRP piles under an axial load (b).
Figure 8.
Effect of surface roughness under an axial load (a) and effect of loading rate on CFRP piles under an axial load (b).
Figure 9.
Effect of confined pressure on GFRP piles under an axial load (a) and effect of relative density on GFRP piles under an axial load (b).
Figure 9.
Effect of confined pressure on GFRP piles under an axial load (a) and effect of relative density on GFRP piles under an axial load (b).
Figure 10.
Effect of FRP types under a lateral load (a) and effect of diameter under a lateral load (b).
Figure 10.
Effect of FRP types under a lateral load (a) and effect of diameter under a lateral load (b).
Figure 11.
Aging effect on GFRP piles under a lateral load (a) and aging effect on CFRP piles under a lateral load (b).
Figure 11.
Aging effect on GFRP piles under a lateral load (a) and aging effect on CFRP piles under a lateral load (b).
Figure 12.
Crack on the tension side of the GFRP pile after aging in pH = 12.
Figure 12.
Crack on the tension side of the GFRP pile after aging in pH = 12.
Figure 13.
Surface roughness (Rt), confined pressure (σc), and relative density (Dr) affecting the behaviour of FRP piles under an axial load.
Figure 13.
Surface roughness (Rt), confined pressure (σc), and relative density (Dr) affecting the behaviour of FRP piles under an axial load.
Figure 14.
Illustration of the interfacial resistance between soil particles and the surface of the FRP piles.
Figure 14.
Illustration of the interfacial resistance between soil particles and the surface of the FRP piles.
Figure 15.
The aging environment and FRP type affect the behaviour of FRP piles under a lateral load.
Figure 15.
The aging environment and FRP type affect the behaviour of FRP piles under a lateral load.
Figure 16.
3D construction of the model.
Figure 16.
3D construction of the model.
Figure 17.
Validation of the axial load for the numerical and experimental results for GFRP (a) and CFRP (b).
Figure 17.
Validation of the axial load for the numerical and experimental results for GFRP (a) and CFRP (b).
Figure 18.
Validation of the lateral load for the numerical and experimental results for GFRP (a) and CFRP (b).
Figure 18.
Validation of the lateral load for the numerical and experimental results for GFRP (a) and CFRP (b).
Figure 19.
Effect of sand dilation under an axial load on CFRP pile settlement.
Figure 19.
Effect of sand dilation under an axial load on CFRP pile settlement.
Figure 20.
Effect of the Young’s modulus of sand under a lateral load on CFRP pile deflection.
Figure 20.
Effect of the Young’s modulus of sand under a lateral load on CFRP pile deflection.
Table 1.
Mixture conditions of mortar.
Table 1.
Mixture conditions of mortar.
Name | Cement:Sand:Aggregate | Water/Cement | Silica Fume % | Superplasticiser % |
---|
Mortar | 1:2:0 | 0.4 | 10 to cement | 0.15 |
Table 2.
Program for the effect under axial load.
Table 2.
Program for the effect under axial load.
Effect of Study | Pile Type | No. of Tests | Confined Pressure (kPa) | Relative Density % |
---|
Surface roughness | GFRP/CFRP/Mild steel | 3 | 250 | 80 |
Loading rate | CFRP | 3 | 250 | 80 |
Vertical pressure | GFRP | 2 | 250/100 | 80 |
Relative density | GFRP | 2 | 250 | 80/60 |
Table 3.
Program for the lateral flexural stiffness test.
Table 3.
Program for the lateral flexural stiffness test.
Study | Pile Type | No. of Tests | Confined Pressure (kPa) | Relative Density % |
---|
FRP type | GFRP/CFRP | 2 | 120 | 80 |
Pile diameter | CFRP | 2 | 120 | 80 |
Aging in the environment (pH = 2) | GFRP/CFRP | 2 | 120 | 80 |
Aging in the environment (pH = 12) | GFRP/CFRP | 2 | 120 | 80 |
Table 4.
Surface roughness (Rt) of different types of FRP.
Table 4.
Surface roughness (Rt) of different types of FRP.
Pile Type | Rt (µm) |
---|
GFRP | 27.3 |
CFRP | 18.1 |
Mild steel | 7.8 |
Table 5.
Materials used in the numerical modelling.
Table 5.
Materials used in the numerical modelling.
Material | Model | Young’s Modulus, E, (MPa) | Poisson’s Ratio, υ | ϕ (°) | Ψ (°) |
---|
Pile | Elastic | 28,000 | 0.22 | ---- | --- |
Sand | Mohr−Coulomb | 41.5 | 0.31 | 33 | 4 |
Table 6.
Properties of CFRP and GFRP used for the numerical modelling.
Table 6.
Properties of CFRP and GFRP used for the numerical modelling.
Property | Symbol | Unit | CFRP | GFRP |
---|
Density | ρ | g/cm3 | 1.6 | 2 |
Longitudinal Modulus * | E1 | MPa | 135,000 | 50,000 |
Transverse in-Plane Modulus * | E2 | MPa | 10,000 | 40,000 |
Transverse in-Plane Modulus * | E3 | MPa | 10,000 | 8500 |
In-plane Shear Modulus ** | G12 | MPa | 5000 | 4300 |
Out-of-Plane Shear Modulus ** | G23 | MPa | 1900 | 3500 |
Out-of-Plane Shear Modulus ** | G13 | MPa | 5000 | 4300 |
Major in-Plane Poisson’s ratio ** | υ12 | ---- | 0.3 | 0.27 |
Out-of-Plane Poisson’s Ratio ** | υ23 | ---- | 0.5 | 0.5 |
Out-of-Plane Poisson’s Ratio ** | υ13 | ---- | 0.3 | 0.27 |