Post on 15-Jan-2016
The Alaskan Way ViaductThe Alaskan Way Viaduct
Steve Kramer
University of Washington
Seattle, Washington
The Alaskan Way ViaductThe Alaskan Way Viaduct
Steve Kramer
University of Washington
Seattle, Washington
(The interesting stuff, not the structural stuff)
Alaskan Way ViaductAlaskan Way Viaduct
• 2.2 miles long• 86,000 vehicles per day• North of Yesler
Designed by City of Seattle
Constructed in 1950• South of Yesler
Designed by Washington State DOH
Constructed in 1956
Alaskan Way ViaductAlaskan Way Viaduct
© 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping
SeattleSeattleSeattleSeattleSeattleSeattleSeattleSeattleSeattle
Yesler TerraceYesler TerraceYesler TerraceYesler TerraceYesler TerraceYesler TerraceYesler TerraceYesler TerraceYesler Terrace
Elliott BayElliott BayElliott BayElliott BayElliott BayElliott BayElliott BayElliott BayElliott Bay
999999999999999999
Harborview HospitalHarborview HospitalHarborview HospitalHarborview HospitalHarborview HospitalHarborview HospitalHarborview HospitalHarborview HospitalHarborview Hospital
U S Marina HospitalU S Marina HospitalU S Marina HospitalU S Marina HospitalU S Marina HospitalU S Marina HospitalU S Marina HospitalU S Marina HospitalU S Marina Hospital
Mason HospitalMason HospitalMason HospitalMason HospitalMason HospitalMason HospitalMason HospitalMason HospitalMason Hospital
Union DepotUnion DepotUnion DepotUnion DepotUnion DepotUnion DepotUnion DepotUnion DepotUnion DepotKing Street StationKing Street StationKing Street StationKing Street StationKing Street StationKing Street StationKing Street StationKing Street StationKing Street Station
Seattle UniversitySeattle UniversitySeattle UniversitySeattle UniversitySeattle UniversitySeattle UniversitySeattle UniversitySeattle UniversitySeattle University
1ST
4TH
BO
RE
N
E MADISON
RAIN
IER AVE S
S 1
ST
STEW
ART
YESLER WAY
I-5
RAMP
I-90
© 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping
AWV
© 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping
SeattleSeattleSeattleSeattleSeattleSeattleSeattleSeattleSeattle
Yesler TerraceYesler TerraceYesler TerraceYesler TerraceYesler TerraceYesler TerraceYesler TerraceYesler TerraceYesler Terrace
Elliott BayElliott BayElliott BayElliott BayElliott BayElliott BayElliott BayElliott BayElliott Bay
999999999999999999
Harborview HospitalHarborview HospitalHarborview HospitalHarborview HospitalHarborview HospitalHarborview HospitalHarborview HospitalHarborview HospitalHarborview Hospital
U S Marina HospitalU S Marina HospitalU S Marina HospitalU S Marina HospitalU S Marina HospitalU S Marina HospitalU S Marina HospitalU S Marina HospitalU S Marina Hospital
Mason HospitalMason HospitalMason HospitalMason HospitalMason HospitalMason HospitalMason HospitalMason HospitalMason Hospital
Union DepotUnion DepotUnion DepotUnion DepotUnion DepotUnion DepotUnion DepotUnion DepotUnion DepotKing Street StationKing Street StationKing Street StationKing Street StationKing Street StationKing Street StationKing Street StationKing Street StationKing Street Station
Seattle UniversitySeattle UniversitySeattle UniversitySeattle UniversitySeattle UniversitySeattle UniversitySeattle UniversitySeattle UniversitySeattle University
1ST
4THALA
SKA
N W
AY
BO
RE
N
E MADISON
RAIN
IER AVE S
S 1
ST
STEW
ART
YESLER WAY
I-5
RAMP
I-90
© 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping © 1993 DeLorme Mapping
Seattlesection
WSDOTsection
Alaskan Way ViaductAlaskan Way Viaduct
Alaskan Way ViaductAlaskan Way Viaduct
Alaskan Way ViaductAlaskan Way Viaduct
Seattlesection
WSDOTsection
Alaskan Way ViaductAlaskan Way Viaduct
Seattle Section
Alaskan Way ViaductAlaskan Way Viaduct
WSDOT Section
Seismic Vulnerability ConcernsSeismic Vulnerability Concerns
• Loma Prieta earthquake
M=7.1
100 km south of Oakland
• Cypress Structure
Highway 17 in Oakland
Double-deck reinforced concrete structure
Similar age
Similar design requirements
Pile supported due to soft surficial soils
Cypress StructureCypress Structure
Cypress StructureCypress Structure
Alaskan Way Viaduct InvestigationsAlaskan Way Viaduct Investigations
• 1990 WSDOT internal review
• 1991-92 UW review
• 1993-95 UW/WSDOT investigation
• 1995-96 WSDOT seawall investigation
UW / WSDOT InvestigationUW / WSDOT Investigation
WSDOT Seawall InvestigationWSDOT Seawall Investigation
• Structural Engineering Aspects
• Geotechnical Engineering Aspects
• Seawall performance
• Effects on AWV
• Remediation strategies
Geotechnical Engineering InvestigationGeotechnical Engineering Investigation
• Site characterization
• Seismic hazard analysis
• Ground response analyses
• Foundation response characteristics
• Evaluation of liquefaction hazards
Site CharacterizationSite Characterization
• Review of historical records
• Review of previous subsurface investigations
• Supplemental subsurface investigations
SPT
CPT
Seismic cone
Downhole seismic
Seattle, 1888Seattle, 1888Historical RecordsHistorical Records
Seattle, 1884Seattle, 1884Historical RecordsHistorical Records
Lake Washington
Yesler
I-5
Looking NW fromBeacon Hill
Looking north along waterfront
Looking eastfrom Elliot Bay
Seattle Regrading ActivitiesSeattle Regrading Activities
Tideflats, 1896
Tideflat ReclamationTideflat Reclamation
Tideflat ReclamationTideflat Reclamation
Railroad Avenue - 1920sRailroad Avenue - 1920s
Railroad Avenue - 1920sRailroad Avenue - 1920s
Seattle SeawallSeattle Seawall
• 12,000 lb/ft lateral thrust
• Four different wall types
- Timber pile-supported relieving platform (2)
- Pile-supported concrete wall
- Fill and rip rap wall
• Total cost: $1.4 million
Type B Seawall SectionType B Seawall Section
Type B Seawall SectionType B Seawall Section
Precast Section
Master Pile
Timber Relieving Platform
BatterPiles (12)
VerticalPiles (6)
Pile/Platform ConnectionPile/Platform Connection
Seawall ConstructionSeawall Construction
Seawall ConstructionSeawall Construction
40
50
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
-140
-150
-160
250240230220210200190180170160150140130120110100908070605040302010010203040
CL
5060708090100110120130140150160170180190200210220230240250260270280290300310320330340350360370380
60
70
1.25:1
70
60
50
40
30
-90
-100
-110
-120
-130
-140
-150
0
0788737694084927850/4"78/6"
B-7 B-2
R-3 R-4-72-72
Projected117' NW
6541/6"012114450/4"50/3"50/6"
4788/11"50/5"
758950/6"50/4"
9342
1/18"
43765
H-3-93
Projected157' NW
73
8516100+
R-16-82
Projected
55125510100+
R-17-82
Projected
DATE
SCALE VERT.
HORIZ.
SHEET OF
DRAWN BY
JOB S.R. C.S.
WASHINGTON STATE
DEPARTMENT OF TRANSPORTATION
MATERIALS BRANCHMATERIALS ENGINEER
TRANSPORTATION COMMISSION
CITY OF SEATTLE DATUM
ALASKAN WAY VIADUCT
D. C. JACKSON
1"=40'1"=40'
FEB. 1996
FILL2
22
11213281346351/6"
5160/6"84/6"
R-5-68
Projected85' SE
R-6-68
171491612114/10"65/6"
6974100/2"
Projected147' NW
Projected154' NW
H-35-96
Projected 38' SE25' SE
0
42/18"1/12"1/24"
1/60"
20
10
Hole terminateddue to
contaminated soil
MS-2494 99 1102
22' NW
?
?
?
??
TILL
TILLTILL
TILL
CPT38
VIC. BENT 97
VIADUCT STA. 86+15
200' SOUTH OF CLOF YESLER WAY
500
Qc (tsf)
WATER LINE
'
ALASKAN WAY VIADUCT1 1
LSH
FIGURE 6: SECTION E - E'
Fill and Rip Rap Wall SectionFill and Rip Rap Wall Section
Alaskan Way ViaductAlaskan Way Viaduct
• History
-Originally intended as downtown bypass
- Design began in 1948, bids opened 1949
- Seattle section opened April 4, 1953
- WSDOT section opened Sept 3, 1959
- Seneca Street off-ramp opened 1961
- Columbia Street on-ramp opened 1966
• Facts
- 7,600 ft long
- 58,867 yards of concrete, 7,460 tons of rebar
- 171,410 ft of piling
36 ft
22 ft
70 ft
Typical Elevation (WSDOT Section)Typical Elevation (WSDOT Section)
57 ft57 ft
36 ft
22 ft
47 ft
Typical Interior Bent (WSDOT Section)Typical Interior Bent (WSDOT Section)
FoundationsFoundations
WSDOT Section Seattle Section
2’
2.5’
FoundationsFoundations
Seattle Section WSDOT Section
17’
13.5’
12’
12’
3.5’
Seattle Section WSDOT Section
Originally intended to use only H-piles
Contractor requested change
Steel piles - 48 tons
All other piles - 40 tons
S. Massachusetts St.
Columbia St.University
St.
Yesler Way
S. Royal Brougham Way
Blanc
hardSubsurfaceSubsurface
DataData
Stewar
t St.
50 shallow borings by SED in 1948
17 deep borings by WSDOH in mid-1950s
Various borings by others
8 borings with SPT
16 CPT soundings with seismic cone
2 deep borings with downhole seismic
100
50
0
-50
-100
-150
Ele
vaio
n (f
t)
Ele
vatio
n (f
t)
100
0
50
-50
-100
-150
Waterfront FillTideflat Deposit
Till
1000 ft
Bla
nch
ard
Ste
war
t
Uni
vers
ity
Yes
ler
Mas
sach
use
tts
Roy
al B
roug
ham
Subsurface ProfileSubsurface Profile
0
50
100
150
0 10 20 30 40 50
Existing Data
SupplementalSubsurfaceInvestigation
Standard Penetration Resistance (blows/ft)
De
pth
(ft)
Uncorrected SPT ResistanceUncorrected SPT Resistance
Uncorrected CPT Tip ResistanceUncorrected CPT Tip ResistanceD
ep
th (
ft)
0
50
100
150
0 100 200 300 400
Cone Penetration Tip Resistance (tsf)
De
pth
Be
low
To
p o
f T
ill (
ft)
Vs (ft/sec)
0
100
150
200
250
50
0 1000 2000 3000
Shear Wave Velocity (ft/sec)
De
pth
Bel
ow
Top
of T
ill (
ft) FederalBuilding
B-1
B-2
Till StiffnessTill Stiffness
Average
-0.5
0
0.5
0 20 40 60 80
Input MotionsInput Motions
• PSHA (10% in 50 yrs = 475-year return period)- Peak acceleration- Spectral velocities- Bracketed duration
• Design-level response spectrum
• Quasi-synthetic time histories
• Deconvolution to produce 3 “bedrock” motions
Acc
eler
atio
n (g
)
Time (sec)
Ground Response AnalysisGround Response Analysis
• Equivalent linear analyses (SHAKE)
• Nonlinear, effective stress analyses (TESS, DESRA)
• Numerous soil profiles
0 20 30 40 5010
Time (sec)
0.6
0.0
-0.6
0.6
0.0
-0.6
0.6
0.0
-0.6
Acc
eler
atio
n (g
)A
ccel
erat
ion
(g)
Acc
eler
atio
n (g
)
10 ft soft soil
50 ft soft soil
100 ft soft soil
Ground Surface MotionsGround Surface Motions
0.0
Period (sec)
1.0 2.0 3.0 4.0 5.00.0
1.0
2.0
0.5
1.5
2.5
S (g)a
Ground Surface Response SpectraGround Surface Response Spectra
10 ft soft soil
50 ft soft soil
100 ft soft soil
Waterfront FillTideflat DepositTill
Waterfront Fill
Tideflat Deposit
Till
100
50
0
-50
-100
-150
Ele
va
tio
n (
ft)
1000'
Pe
ak
Ac
ce
lera
tio
n (
g)
a max
0.0
0.5
Peak AccelerationsPeak Accelerations
Liquefaction SusceptibilityLiquefaction Susceptibility
• Historical evidence
- Sand boils in 1949 and 1965
- Broken pipes in 1949 and 1965
- Lateral movements in 1965
• Construction techniques
- Hydraulic filling
- Dumping through water
• Previous investigations
- Mabey and Youd (1991)
- Grant et al. (1992)
Scenario Earthquake #1 Scenario Earthquake #2
M 7.5 7.5
a max 0.30 g 0.15 g
Displacement (in.)
>100 14 - 100
84 - 100 6 - 48
45 - 84 2 - 12
10 - 45 0 - 4
Little liquefaction susceptibility but in areas with
steep slopes. Liquefaction is unlikely, but if it
were to occur, large displacements are
possible.
No displacement likely due to liquefaction.
Mabey and Youd (1991)
0
10
20
0 5 10 15 20 25 30 35D
epth
(ft
)
(N )1 60
(N )1 60required to prevent
liquefaction
Liquefaction EvaluationLiquefaction EvaluationStandard Penetration Test
0
10
20
30
40
50
0 5 10 15 20 25 30 35
(N )1 60
Dep
th (
ft)
(N )1 60
required to prevent liquefaction
Liquefaction EvaluationLiquefaction EvaluationStandard Penetration Test
0
10
20
30
40
50
60
70
0 0.25 0.5 0.75 1 1.25
FS L
Dep
th (
ft)
SPT-Based Factor of SafetySPT-Based Factor of Safety
Dep
th (
ft)
(q )c 1
(q )c 1required to prevent
liquefaction
(tsf)
0
10
20
0 100 200 300 400 500
Liquefaction EvaluationLiquefaction EvaluationCone Penetration Test
Dep
th (
ft)
(q )c 1 (tsf)
Liquefaction EvaluationLiquefaction EvaluationCone Penetration Test
0
10
20
30
40
50
0 100 200 300 400 500
(q )c 1required to prevent
liquefaction
0
10
20
0 5 10 15 20 25 30 35D
epth
(ft
)
(N )1 60
Design-levelground motion
Liquefaction EvaluationLiquefaction EvaluationComparison with 1965 observations
Dep
th (
ft)
(N )1 60
0
10
20
0 5 10 15 20 25 30 35
Design-levelground motion
1965groundmotion
Liquefaction EvaluationLiquefaction EvaluationComparison with 1965 observations
0
10
20
30
40
50
0 5 10 15 20 25 30 35
(N )1 60
Dep
th (
ft)
Design-levelground motion
Liquefaction EvaluationLiquefaction EvaluationComparison with 1965 observations
0
10
20
30
40
50
0 5 10 15 20 25 30 35
(N )1 60
Dep
th (
ft)
Design-levelground motion
1965groundmotion
Liquefaction EvaluationLiquefaction EvaluationComparison with 1965 observations
0
10
20
30
40
50
60
70
0 1 2 3
FS L
De
pth
(ft)
SPT-Based Factor of SafetySPT-Based Factor of Safety
1965groundmotion
Effects of LiquefactionEffects of Liquefaction
• Sand boils - expected over most of length
• Post-earthquake settlement
- Up to 1” in fill above water table
- Up to 25” in soft, saturated soils
• Vertical pile movement
- Tip capacity reached at r = 0.6
- Tips of southernmost piles in liquefiable soil
• Lateral pile movement
- Depends on lateral soil movement
- 10”-12” expected to cause bending failure
- Lateral soil movement depends on seawall movement
u
All movements variable due to variability of soil profile
Seawall InvestigationSeawall Investigation
• Transverse profile characterization
- 5 additional borings (2 offshore)
- 3 additional CPT soundings
• Seawall structure characterization
- Member sizes
- Member properties
- Connection strengths
• Computational model
- Soil
- Seawall
- Soil-seawall interaction
Estimation of permanent deformations due to liquefaction
FLAC
FLACFLAC
Fast Lagrangian Analysis of Continua
• Explicit finite difference code• Large-strain capabilities• Several soil constitutive models• Structural elements (beams, piles, cables)• Interface elements (normal and shear)• Coupled stress-deformation and flow capabilities• Incremental construction modeling• Graphical display of results• Dynamic option• Creep option• FISH programming language
Alaskan Way Viaduct
Type B Wall ModelType B Wall Model
Entire Section
Alaskan Way Viaduct
Type B Wall ModelType B Wall Model
Entire Section
3400 soil elements610 structural elements
Type B Wall ModelType B Wall Model
Precast Section
Master Pile
Timber Relieving Platform
BatterPiles (12)
VerticalPiles (6)
Type B Wall ModelType B Wall Model
Modeling ApproachModeling Approach
Strain
Stress
G G fi
Strain due to softening
• Primary effects of liquefaction
- Reduction of soil strength
- Reduction of soil stiffness
• Stiffness reduction approach1. Analyze with pre-liquefaction properties
2. Analyze with post-liquefaction properties
3. Subtract pre-liquefaction displacements from post-liquefaction displacements
DisplacementsDisplacements
MaximumDispl = 0.71 ft
Deformed ShapeDeformed Shape
Deformations magnified by factor of 5
Bending MomentsBending Moments
Type B WallType B Wall
Beforeliquefaction
Type B WallType B Wall
Duringliquefaction
Type B WallType B Wall
Afterliquefaction
Fill and Rip Rap WallFill and Rip Rap Wall
Beforeliquefaction
Fill and Rip Rap WallFill and Rip Rap Wall
Duringliquefaction
Fill and Rip Rap WallFill and Rip Rap Wall
Afterliquefaction
Columbia St.
Madison St.University St.
S. Washington St.
Zones of Large Lateral MovementsZones of Large Lateral Movements