LIQUEFACTION‐INDUCED SETTLEMENTS OF BUILDINGS WITH 

SHALLOW FOUNDATIONS

Kohji Tokimatsu, Tokyo Institute of Technologyliquefaction@mac.com

1. Key parameters found in the field2. Key parameters found from  centrifuge 

experiments3. key challenges and paths forward 

1. Key parameters observed in the field

Yoshimi, Y., and Tokimatsu, K. (1977): Settlement of buildings on saturated sand during earthquakes, Soils and Foundations, 17(1), 23–38.

Effects of WB/HL on Normalized building settlement (SB/HL) 

WB/HL

3

S B/H

L(%) WB

HL

SB

Effects of Thickness of Surface Crust

Ishihara, K. (1985): Stability of natural deposits during earthquakes, Proc., 11th ICSMFE, Vol. 1, 321‐376.

Thickness of Crust, HNL(m)

Thickness o

f Liquefie

d Layer, H L

 (m)

HNL

HL

Ground Surface

Liquefied Layer

Effects of contact pressure or stories

Tokimatsu, K., Kojima, J., Kuwayama, S., Abe, A., and Midorikawa, S. (1994): Liquefaction‐induced damage to buildings during 1990 Luzon Earthquake, J. Geotech. Engrg., 120(2), 290–307.

Average Bu

ilding 

Settlement, S B

(cm)

Number of Stories

Effects of HL on Building Settlement

Tokimatsu, K., Kojima, J., Kuwayama, S., Abe, A., and Midorikawa, S. (1994): Liquefaction‐induced damage to buildings 1990 Luzon Earthquake, J. Geotech. Engrg., 120(2), 290–307.

No liquefaction without building settlement

Marginal zone without building settlement

Extensive liquefaction with building settlement less than 50 cm

Extensive liquefaction with building settlement more than 50 cm

Building Settlement, S B

Estimated Thickness of Liquefied Layer, HL (m)

Sancio, R., Bray, J. D., Durgunoglu, T., and Onalp, A. (2004): Performance of buildings over liquefiable ground in Adapazari, Turkey, Proc., 13th World Conf. on Earthquake Engineering, St. Louis, Mo., Canadian Association for Earthquake Engineering, Vancouver, Canada, Paper No. 935.

Effects of aspect ratio on building settlements

WB

HB

SB

Normalize

d Bu

ilding Settlement, S B/W

B

Building Aspect Ratio, HB/WB

Ground Settlement vs Tilt Angle of Houses1/20~

Tokimatsu, K., Tamura, S., Suzuki, H., and Katsumata, K. (2012): Building damage associated with geotechnical problems in the 2011 Tohoku Pacific Earthquake, Soils and Foundations, 52(5), 956-974.

Average Ground Settlement, SG (cm)

Damage Classification in Tilt Angle (%

)

1964 Niigata Earthquake 2011 Tohoku Earthquake1960             1962                1982                     2000

Unreinforced concrete foundations   Structural Damage

Reinforced concrete foundationsBuilding settlement & Tilt

Effects of Foundation Rigidity on Failure Mode

WB

qB

Non‐liquefied CrustGroundwater Table

Liquefiable Layer 

HNL or H1Shear StrengthDrLHL or H23D Drainage

Number of Stories, N

Input motion (Amax, Duration, Sequence)

Building Response

HB

Aspect Ratio, WB/HBContact Pressure, qBMass Eccentricity

Building Settlement, SBuilding TiltStructural Damage

Ground SettlementLocation of Ejecta

Foundation Rigidity

Key Parameters Observed in the Field

Structure‐to‐StructureInteraction 

(1) Liquefaction-induced settlements of buildings with shallow foundations were affected by various factors, relative effects of which have not been clearly identified.

(2) A simplified procedure should be pursued for better understanding of the mechanism that could explain building damage in most of the complied case histories.

Summary from Field Observation

2. Key parameters found in the lab

Description of Centrifuge Shaking Table Tests

13

8 silica sand(Dr=50% or 65%)

7 silica sand (Dr=50%)silicon oil (50cst)

7 silica sand(Dr=50% or 65%)

700

200(10m)

220

(unit mm)(model scale)

Experimental VariablesContact pressureBuilding height and widthMass eccentricity ratioGroundwater depthThickness and Density of Liquefied soil 

Input PGACentrifuge Acceleration50g with small container25g with large container

1stM2LM3LM4L

◆●■

Effects of Groundwater Table

140             1              2              3              4Relative Settlemen

t(cm)

0

50

40

30

20

10

Absolute Settle

men

t(cm

)

0

50

40

30

20

10 Tilt An

gle(rad)

0

0.03

0.02

0.01

0            1              2              3             4Groundwater Table (m)

Groundwater Table (m)

15

建物模型7MSを用いた全実験モデルにおける1回目加振時の実験結果

Dr=90%

Dr=50%

Dr=65%

Dr=90%

Dr=50%

Dr=80～90%

Dr=50%

Dr=65%

Effects of Soil Density & Location of Liquefied Soil

0

50

40

30

20

10

0

50

40

30

20

10

Case 1 Case 1

Case 1

Relative Settlemen

t(cm)Ab

solute Settle

men

t(cm

)

Tilt An

gle(rad)

0

0.03

0.02

0.01

0             1              2              3              4

0              1               2             3              4

Case 3

Case 2

Case 3

Case 2

Case 3Case 2

Groundwater Table (m)

Groundwater Table (m)

Case 1 Case 2 Case 3

Effects of Input Motions

160

50

40

30

20

10

0

50

40

30

20

10

Accmax=4m/s2

Accmax=2m/s2

Accmax=4m/s2

Accmax=2m/s2

Accmax=4m/s2

Accmax=2m/s2

Relative Settlemen

t(cm

)Ab

solute Settle

men

t(cm

)

Tilt An

gle(rad)

0

0.03

0.02

0.01

Groundwater Table (m)

0             1              2              3              4

0              1              2              3              4

Groundwater Table (m)

Factor of Safety against Vertical Load

17

FSW ＝ RW / LWResistance

RW＝

Self‐Weight of BuildingLw＝ (m1+m2+me)g m1

me

B

m2 σv’

Z

E.P.W.P.R0 1

K : Earth Pressure Coefficientσv’ : Effective StressZ : Thickness of Non‐liquefied Crustθ : Internal Friction AngleB , L : Dimension of Foundationm1 , m2 , me : Mass of Buildingg : Gravitational Acceleration

m1

me

B

m2 σv’

h1h2

e

a2

a2

Z

a1

E.P.W.P.R0 1

Factor of Safety against Overturning Moment

18

FSMe＝ RMe / Lme

Resisting Moment

RMe＝

Driving MomentLMe＝ (m1 +m2)gB/2 +meg(B/2+e) +m1a1h1 +(m2+me)a2h2K : Earth Pressure Coefficientσv’ : Effective StressZ : Thickness of Non‐liquefied Crustθ : Internal Friction AngleB , L : Dimension of Foundationm1 , m2 , me : Mass of Buildingg : Gravitational Accelerationa1 , a2 : Building Accelerationh1 , h2 : Heighte :Eccentric Distance

Factors of Safety vs Building Settlement and tilting

190.01              0.1                 1                 10

Factor of Safety against Vertical Force, FSW

0

80

60

40

20

0

80

60

40

20

0.01               0.1                  1                 10

Ground Settlement● ～5cm● 5～10cm● 10～15cm● 15cm～

Factor of Safety against Overturning Moment FSMe

Relative Settlemen

t (cm

)Ab

solute Settle

men

t (cm

)

Tilt An

gle (rad)

0

0.06

0.04

0.02

Summary from Centrifuge Experiment

(1) The relative settlement and tilt angle of a building decreased as the crust thickness (HNL) and the density of liquefied soil (DrL) increased or the thickness of the liquefied soil (HL) and building contact pressure (qB) decreased. (2) The effects of soil liquefaction on building damage were well accounted for by the safety factors against vertical force and static and dynamic overturning moments of the building together with the liquefaction severity of the underlying liquefiable deposit, represented by the integration of liquefaction-induced volumetric strain with depth.

3. KEY CHALLENGES AND PATHSFORWARD

(1) Compilation/revisit of well documented case histories of liquefaction‐induced ground and building settlements during resent earthquakes.(2) Centrifuge experiments to identify relative effects of key parameters on building settlements.(3) Development of a simplified procedure that can explain liquefaction-induced building damage in most of the complied case histories and centrifuge experiments.

3. KEY CHALLENGES AND PATHSFORWARD (CONT.)

(4) Refinement of numerical and design procedures to estimate ground and building settlements, which should be substantiated by well‐documented case histories and centrifuge experiments.(5) Development of cost effective mitigation techniques taking into account the key parameters controlling settlement and tilting of buildings.