This document discusses various geotechnical aspects related to earthquake-resistant design. It summarizes case studies of earthquakes where soil conditions influenced the level of damage to structures. Specifically, it discusses how liquefaction of saturated, loose soils can cause severe damage during earthquakes. Factors like soil density, water table level and drainage conditions are important for liquefaction potential. The case study of the 1964 Niigata earthquake is discussed to show how variations in soil properties with depth influenced the level of damage to different structures.

3. Niigatta Earthquake: 1964, Mag. 7.5

4. Japan earthquake 1964: Niigata- Mag. 7.5

5. Tokachi-oki Earthquake: 2003 The Damage of Sewerage Structures kushiro (Town) Lifted up manhole and gushed soil during liquefaction Lifted up manhole

6. Caracas Earthquake 1967: Mag. 6.6

7. Chile Earthquake 1960 : Island nearValdivia- Mag. 9.5

8. Alaska Earthquake 1964:Mag. 9.2

14. Site approximately same distance from the zone of energy release – 1957 San Francisco Earthquake

15. Site approximately same distance from the zone of energy release – 1957 San Francisco Earthquake

16. Effect of Soil Conditions on form of Response Spectra –Site A

17. Effect of Soil Conditions on form of Response Spectra –Site B

18. Effect of Soil Conditions on form of Response Spectra – Site C

19. Effect of Soil Conditions on form of Response Spectra – Site D

20. Effect of Soil Conditions on form of Response Spectra – Site E

21. Effect of Soil Conditions on form of Response Spectra – Site F

22. Effect of Soil Conditions on form of Response Spectra – Site A - F

27. Damage potential coefficient varies with building characteristics and soil depth

28. Relationship between building characteristics, soil depth and damage potential coefficient (S v /k) Structure Fundamental period Damage intensity (D r ) 2 to 3 storey 0.2 sec Remains same regardless of soil depth 4 to 5 storey 0.4 sec Max. damage intensity expected at soil depth of about 20 to 30 m 10 to 12 storey 1.0 sec Damage intensity expected to increase with soil depth up to 150 m or so 15 to 20 storey Damage intensity even greater for soil depth of 150 to 250 m & relatively low for soil depth up to 80 m or so

31. Ultimate bearing capacity of continuous shallow foundation (static case)

32. Seismic bearing capacity

40. Total stress, Pore water pressure and Effective stress Figure-1 Figure-2 Case Total Pressure Pore Pressure Effective Pressure Figure- 1 475 150 325 Figure- 2 475 250 225

44. Influence of soil conditions on liquefaction potential

45. The Damage of Embankment Structures Toyokoro Collapsed Embankment

46. Place where Embankment was collapsed Abashiri River (1) Shibetsu River (6) Kushiro River (5) Kiyomappu River (2) Tokachi River (66) Under investigation Lateral Spread was observed ( ) : the number of collapsed points Tokachi River The Damage of Embankment Structures

47. Toyokoro Liquefied Soil Collapsed Embankment The Damage of Embankment Structures Liquefied Soil

48. Failure Mode (notice : this is only concept) Liquefied Stratum Embankment Settlement Land Slide Lateral Spread The Damage of Embankment Structures

49. The Damage of Port Structures (at Kushiro Port) Kushiro Settlement behind Quay Wall Trace of Sand Boiling

50. Alaska Earthquake ( 1964 )

52. Caracas ( 1967 )

53. Alaska 2002 Boca del Tocuyo, Venezuela, 1989

54. Lateral spread at Budharmora (Bhuj, 2001)

55. Arial view of kandla port, Marked line sows ground crack and sand ejection (Gujrat Earthquake 2001)

59. Soil conditions in Areas where Liquefaction has occurred : Case Study: Niigata Earthquake Kawangishicho apartment complex, tipped by 60 degree

65. Relationship between N at the base of Foundation and Extent of Damage

66. Relationship between depth of pile, ‘N’ of sand at pile tip and Extent of Damage (Zone-C)

80. SPT overburden correction factor & values of (N 1 ) 60

81. τ av = τ cyc = 0.65 τ max = 0.65 r d ( σ vo / σ ’ vo )(a max /g) r d = Stress reduction factor = 0.960 at 6.2m depth=C D

84. Details of calculation

85. Extensive liquefaction observed for upper 8-10m & at greater depth Peak horizontal acceleration at Niigata 0.2g to 0.3g (> 0.16g ) Extensive liquefaction predicted in this problem is consistent with actual observation in 1964 Niigata earthquake

87. SAFETY AGAINST LIQUEFACTION Zone Depth below ground level ‘ N’ value III, II Up to 5 m 15 III, II Up to 10 m 25 II (For important structure) Up to 5 m 10 II (For important structure) Up to 10 m 20

88. Liquefaction Potential Damage Range of SPT N corrected Potential Damage 0-20 High 20-30 Medium > 30 No Significant Damage

92. Cross-section(Retaining Geogrid Reinforced cohesionless backfill)

93. Field Performance of wall 4 O.P. Fixed in the Wall: To monitor the lateral movement of wall top away from backfill using Electronic Distance Meter for a period of 36 months

95. Hyogoken Nambu Earthquake 1995 Height of wall – 4 to 8 m Conventional Retaining Wall – suffered maximum damage Geo-synthetic reinforced soil retaining wall –Performed very well (due to relatively high ductility of the wall)