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Figure 2.13: Permanent Ground Displacements in the Upstream Area of the Shinano River The Showa Bridge was located approximately 55 km from the epicenter of the earthquake; its construction was finished five months prior to the earthquake. As shown in Figure 2.12, five simply-supported steel girders, each about 28-m spans, fell into the water (Hamada 1992). Bridge piers were supported on steel pipe piles driven through loose sands into medium dense fine sands about 15 m below the mudline. The abutments and the piers were pile bents with nine single row piles, 609 mm in diameter and 22 to 25 m in length. Deformation of the piles, resulting from the loss of lateral support from the liquefied loose sands, allowed the unconnected, simply supported spans to fall off the pier supports. After the failure, the steel pipe 20
piles supporting the fourth pier, located within the river, were extracted and examined. Their deformed shapes indicate that about 0.5 m of lateral displacement occurred at the level of the riverbed and that ground displacement reached depths as great as 7 to 8 m below the bed. The left abutment moved about 1 m toward the center of the river, and its approach road settled considerably. Hamada (1992) noted that horizontal displacement of the piers supporting the Showa Bridge was much less than the displacement of the ground a short distance either upstream or downstream from the bridge. This reduced displacement indicates that the bridge restrained ground deformation. Further evidence of the influence of pile foundations on lateral spread displacement is illustrated by the aerial photographs of Hamada (1992). Calculated vectors of ground displacement indicate that riverbank displacements were about 8 to 9 m upstream from the Bandai Bridge in Niigata City, and only about 4 to 5 m near the bridge. Therefore, the bridge apparently restrained lateral ground movement by about 4 m. Immediately downstream of the Showa Bridge is the Yachiyo Bridge. Its pier foundations were pushed toward the river due to large ground displacements while displacement at the top of the piers was restrained because of the resistance of the girders. The damage to the abutments and piers is shown in Figures 2.14 and 2.15. The foundations of the abutments and piers P1 and P2 had been constructed on reinforced concrete piles with a diameter of 300 mm and a length of about 10 m. Pier 2 was broken at the level of the ground surface with the permanent deformation between the top of the broken pier and the lower part of the pier being 1.1 m. It was reported that the pile was severely damaged about 8 m from the top, and horizontal cracks, which could have been caused by large bending moments, were found throughout both piles. Figure 2.14: Damage to Yachiyo Bridge 5, 6 This earthquake also provided Hamada (1992) an opportunity to make detailed measurements of reinforced concrete pile deformations caused by lateral spreads at the NHK and Niigata Family Courthouse (NFCH) Buildings. The NHK building was a four-story reinforced concrete building supported on reinforced concrete piles 35 cm in diameter. Excavations performed 20 years after the earthquake revealed extensive damage (Figure 2.16). The NFCH was a three-story reinforced 21
Page 1: ASSESSMENT AND MITIGATION OF LIQUEF
Page 5 and 6: ACKNOWLEDGMENTS The authors would l
Page 7 and 8: ASSESSMENT AND MITIGATION OF LIQUEF
Page 9 and 10: 8.0 HAZARD EVALUATION AND DEVELOPME
Page 11 and 12: LIST OF FIGURES Figure 1.1: ODOT’
Page 13: Figure 8.8: Long Valley Dam and Lak
Page 16 and 17: Design of a given component shall l
Page 18 and 19: Liquefaction Mitigation Procedure G
Page 20 and 21: Pacific Northwest also are summariz
Page 23 and 24: 2.0 OVERVIEW OF LIQUEFACTION-INDUCE
Page 25 and 26: oughly 50 centimeters, with numerou
Page 27 and 28: supported bridges along the Seward
Page 29 and 30: Another area of extensive bridge da
Page 31 and 32: Nineteen bridges were also damaged
Page 33: 1. No foundation failures were obse
Page 37 and 38: Figure 2.17: Observed Pile Deformat
Page 39 and 40: Figure 2.19: Damage from the 1906 S
Page 41 and 42: Figure 2.22: Ground Deformations Ne
Page 43 and 44: induced ground displacement was the
Page 45 and 46: Well-documented case histories of t
Page 47 and 48: Similar damage to pile foundations
Page 49 and 50: Examples of acceptable bridge found
Page 51 and 52: Numerous investigations of liquefac
Page 53 and 54: 3.0 EVALUATION OF LIQUEFACTION SUSC
Page 55 and 56: The evaluation of liquefaction haza
Page 57 and 58: Table 3.1: Estimated Susceptibility
Page 59 and 60: movements, or localized ground disp
Page 61 and 62: Shear wave velocities can now be ob
Page 63 and 64: 3.4 LIQUEFACTION RESISTANCE: EMPIRI
Page 65 and 66: Figure 3.1: Range of r d Values for
Page 67 and 68: The earthquake-induced shearing str
Page 69 and 70: drill rod during hammer impact. In
Page 71 and 72: Figure 3.5: Minimum Values for K σ
Page 73 and 74: 3.4.2.2.1 CPT Method Developed by R
Page 75 and 76: 1. Sensitive, fine grained 6. Sands
Page 77 and 78: Figure 3.9: CPT-Based Curves for Va
Page 79 and 80: CRR where: q c 2 3 0.00128 0.0
Page 81 and 82: Tacoma, Washington (Dickenson and B
Page 83 and 84: Table 3.8: Influence of OCR on the
Page 85 and 86:
Figure 3.13: Influence of Fines Con
Page 87:
Gravel Sand Figure 3.16: Relationsh
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FS L > 1.4: Excess pore pressure ge
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The post-liquefaction strength of s
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Figure 4.3: Undrained Critical Stre
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4.3 INTRODUCTION TO MODES OF FAILUR
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Figure 4.5: (a) Relationship betwee
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not available for many case studies
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provided to give the recommended ra
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Figure 4.8: Overview of EPOLLS Mode
Page 106 and 107:
Figure 4.10: Model of Hypothetical
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4.5.2 Advanced Numerical Modeling o
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Figure 4.12: Post Volumetric Shear
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The relationship shown in Figure 4.
Page 114 and 115:
A third type of failure is shown in
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Table 5.1: Liquefaction Remediation
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5.3 DESIGN OF SOIL MITIGATION The d
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soil improvement guidelines state t
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The models were instrumented with a
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The model uses an explicit method,
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A simplification was made in the mo
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permanent earthquake displacements)
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7.0 DEFORMATION ANALYSIS OF EMBANKM
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engineers; (2) requisite input incl
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π g 2 a t I a 2 dt (7-1) The A
Page 136 and 137:
10 1 Bracketed Intensity (m/s) 0.1
Page 138 and 139:
7.3 PARAMETRIC STUDY A well-validat
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the rigid body methods. The point a
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0.4 Acceleration (g) 0.2 0 -0.2 -0.
Page 144 and 145:
Embankment Height (m) Depth of Liqu
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10 1 DISPLACEMENT (m) 0.1 Morgan Hi
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2.0 Embankment Toe Embankment Mid-S
Page 150:
suitably reliable estimates of perm
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interest. Specifically, the peak be
Page 155 and 156:
Flow Chart for Evaluation and Mitig
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The deformation evaluations were pe
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Portland (a) (b) Figure 8.2: Illust
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Figure 8.4: Contours of PGA on Rock
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Borehole 4E CPT Hole 4E 26.0' NGVD
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8.4.2 Subduction Zone Bedrock Motio
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154 Table 8.5: Selected Acceleratio
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Spectral Acceleration (g) 1.50 1.40
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with the calculated equivalent unif
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n ( M 10 1) (8-1) where M is the
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0.20 0.15 0.10 Acceleration (g) 0.0
Page 177 and 178:
15.0 12.5 10.0 Long Valley Dam Lake
Page 179 and 180:
CSR should be modified for the pres
Page 181 and 182:
8.7 EVALUATION OF INITIATION OF LIQ
Page 183 and 184:
crest stage Marine Drive 42.5 ft NG
Page 185 and 186:
Table 8.9: Fines Content Values Est
Page 187 and 188:
large sliding and long-term disrupt
Page 189 and 190:
Table 8.12: Deformation Results fro
Page 191 and 192:
The earthquake time histories used
Page 193 and 194:
North (river) South (land) North To
Page 195 and 196:
Table 8.20: Riverward Deformation R
Page 197 and 198:
applications (DDC, closely spaced v
Page 199 and 200:
Table 8.21: Comparison of Predicted
Page 202 and 203:
9.0 SUMMARY AND CONCLUSIONS Recent
Page 204:
dewatering may be warranted. Additi
Page 207 and 208:
Bardet, J.P. (1990). “LINOS - A N
Page 209 and 210:
California Division of Mines and Ge
Page 211 and 212:
Fujii, S., M. Cubrinovski, K. Tokim
Page 213 and 214:
Ishihara, K. and M. Cubrinovski. (1
Page 215 and 216:
Liu, A.H. and J.P. Stewart. (1999).
Page 217 and 218:
Oregon Department of Transportation
Page 219 and 220:
Schnabel, P., J. Lysmer, and H.B. S
Page 221 and 222:
Sun, I.H. and I.M. Idriss. (1992).
Page 223:
Youd, T.L. and C.F. Jones. (1993).
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