LIST OF FIGURES

Figure page

2-1. Mohr-coulomb failure criterion ................. ......... .... ............... 11

2-2. Schematic for ductility factor component definitions .............................................15

2-3. Schematic for energy method ductility factor ......... ............. .. ............. ....16

2-4. Schematic for deformation method ductility factor ..............................................18

3-1. C F R P grid round tubes ...................................................................... ...................25

3-2. CFRP grid cylinder casting in the field ........................................... ............... 25

3-3. CFRP grid ............. ... ........................ ........ ............ .......26

3-4. CFRP strand tests................ ................................. 27

3-5. Stress-strain curves of CFRP grid strands............................. ................28

3-6. Typical load head movement rate for control cylinders ......................... ..........29

3-7. Typical load rate for control cylinders ............................................ ............... 30

3-8. CFRP grid cylinder test set-up............... .......................................... ............... 30

3-9. Cylinders after testing .......................... .......................................... ............... 31

3-10. Stress-strain curves for control cylinders ...................................... ............... 32

3-11. Stress-strain curves for grid cylinders 1, 2 and 3 ............................................. 33

3-12. Stress-strain curves for grid cylinders 4, 5 and 6 .............................................. 33

3-13. Stress-strain curves for typical control and grid cylinders ....................................34

3-14 C ylindrical pressure vessel ............................................................ .....................36

3-15. M modified Hognestad stress-strain curve ....................................... ............... 38

3-16. Experimental and empirical model stress-strain curves .......................................39