Earthquake Engineering and the Alaskan Way Viaduct

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Washington Seattle, Washington Structural

amplification Strong ground surface motio

1 Earthquake Engineering and the Alaskan Way Viaduct Steve Kramer University of Washington Seattle, Washington Structural Caused by excessive ground shaking Strongly influenced by local soil conditions Geotechnical Caused by ground failure Strongly influenced by local soil conditions Structural Structural Mexico City, 1985 Low bedrock accelerations Strong amplification Strong ground surface motio Loma Prieta, 1989 Modest rock accelerations Strong amplification Strong ground surface motions Structural Engineering for Earthquakes Structures San Fernando, 1971 Strong motion Lack of transverse reinforcement

2 Engineering for Earthquakes Structural Engineering Considerations Design of new structures Engineering for Earthquakes Design Considerations Performance objectives Retrofitting of existing structures Immediate Occupancy Life Safety Collapse Preven Immediate Occupancy Life Safety Collapse Prevention Seismic Loading on Structures Vertical seismic loads Gravity load (vert Weight of struct Weight of conte Horizontal seismic loads Earthquake motion

Seismic Loading on Structures Seismic Loading

lengthening/shortening Types of structures

Diagonal bracing resists lengthening and

3 Seismic Loading on Structures Seismic Loading on Structures Rotation Shortening Lengthen Earthquake motion To prevent excessive movement, must restrain rotation and/or lengthening/shortening Types of structures Moment frame Types of structures Braced frame Diagonal bracing resists lengthening and shortening Strong beam/colu connectio resist rotation Concrete Shear Wall Structural Materials Masonry Very brittle if unreinforced Common in older structures Common facing for newer structures Shear wall resists rotation and lenthening/ shortening

4 Structural Materials Timber Structural Materials Concrete Heavy, brittle by itself Ductile with reinforcement Rebar Structural Materials Steel Light, ductile Easy connections Structural Damage Masonry Watsonville Iran San Francisco Structural Damage Timber Structural Damage Timber Soft first floo

5 Structural Damage Reinforced Concrete Overturning Axial Structural Damage Reinforced Concrete Rebar La Insufficient confinement Reinforced Concrete Co Structural Damage Reinforced Concrete Structural Damage Steel Fractured weld Increased confinement Liquefaction Occurs in loose, saturated sands Grain structure collapses Pore pressure increases Liquefaction Niigata, 1964 Liquefaction Bearing failure Effective stress decreases Strength and stiffness decrease

6 Liquefaction Liquefaction Kobe, 1995 Liquefaction Lateral spreading Niigata, 1964 Liquefaction Lateral spreading Pile foundation failure Liquefaction Landslides Can occur due to liquefaction Can occur in non-liquefiable soil Landslides Landslides Peruvian Andes, 197 Yungay, Peru

Landslides Landslides Yungay, Peru Peruvian Andes,

Peruvian Andes, 197 Peruvian Andes, 197 Landslides

pressure on back of wall increases Passive pressure

7 Landslides Landslides Yungay, Peru Peruvian Andes, 197 Landslides Source Landslides Source Yungay Peruvian Andes, 197 Peruvian Andes, 197 Landslides Yungay, Peru Retaining Structure Failures Active pressure on back of wall increases Passive pressure on front of wall decreases Wall translates and/or rotates Before After

Retaining Structure Failures Retaining Structure Failures Port of Kobe, 1995 Port of Seattle, 1965 Retaining Structure Failures Port of Kobe, 1995 Lifelines Gas Electrical power Water Sewer Storm

8 Retaining Structure Failures Retaining Structure Failures Port of Kobe, 1995 Port of Seattle, 1965 Retaining Structure Failures Port of Kobe, 1995 Lifelines Gas Electrical power Water Sewer Storm drain Data Highways Bridges Ports Lifelines Lifelines Gas Electrical power Water Sewer Storm drain Data Required for physical health Gas Electrical power Water Sewer Storm drain Data Required for physical health Highways Bridges Ports Highways Bridges Ports Required for economic health

Washington State DOH Constructed in 1956 Elliott Bay Bay AWV STEWART 1ST S 1ST 4TH BOREN Seattle Mason Hospital YESLER WAY King

9 Lifelines Natural Gas Lifelines Water Lifelines Lifelines Ports Transportation Alaskan Way Viaduct Alaskan Way Viaduct 2.2 miles long 86, vehicles per day North of Yesler Designed by City of Seattle Constructed in 195 South of Yesler Designed by Washington State DOH Constructed in 1956 Elliott Bay Bay AWV STEWART 1ST S 1ST 4TH BOREN Seattle Mason Hospital YESLER WAY King Street Station Union Depot I-5 E MADISON Seattle University Harborview Hospital Yesler Terrace RAINIER AVE S 99 RAMP U S Marina Hospital I DeLorme Mapping

Alaskan Way Viaduct Alaskan Way Viaduct STEWART 4TH BOREN Mason Hospital E MADISON Seattle University Seattle section ALASKAN WAY 1ST Seattle I-5 Harborview Hospital Elliott

Alaskan Way Viaduct Seattle Section Seattle section WSDOT section Alaskan Way Viaduct Seismic Vulnerability Concerns WSDOT Section Loma Prieta earthquake M=7.

10 Alaskan Way Viaduct Alaskan Way Viaduct STEWART 4TH BOREN Mason Hospital E MADISON Seattle University Seattle section ALASKAN WAY 1ST Seattle I-5 Harborview Hospital Elliott Bay Bay WSDOT section S 1ST King Street Station YESLER WAY Union Depot Yesler Terrace RAINIER AVE S 99 RAMP U S Marina Hospital I DeLorme Mapping Alaskan Way Viaduct Alaskan Way Viaduct Seattle Section Seattle section WSDOT section Alaskan Way Viaduct Seismic Vulnerability Concerns WSDOT Section Loma Prieta earthquake M=7.1 1 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 Structure Cypress Structure Alaskan Way Viaduct Investigations UW / WSDOT Investigation 199 1991-92 1993-95 1995-96 WSDOT internal review UW review UW/WSDOT investigation

Geotechnical Engineering Investigation Site characterization Seismic hazard analysis Ground response analyses Foundation response characteristics Evaluation of liquefaction

11 Cypress Structure Cypress Structure Alaskan Way Viaduct Investigations UW / WSDOT Investigation WSDOT internal review UW review UW/WSDOT investigation WSDOT seawall investigation Structural Engineering Aspects Geotechnical Engineering Aspects WSDOT Seawall Investigation Seawall performance Effects on AWV Remediation strategies Geotechnical Engineering Investigation Site characterization Seismic hazard analysis Ground response analyses Foundation response characteristics Evaluation of liquefaction hazards Site Characterization Review of historical records Review of previous subsurface investigations Supplemental subsurface investigations - SPT - CPT - Seismic cone - Downhole seismic

12 Historical Records Seattle, 1888 Historical Records Seattle, 1884 Lake Washington I-5 Yesler Looking NW fro Beacon Hill Looking north along waterfron Tideflat Reclamation Tideflats, 1896 Looking east from Elliot Ba

Tideflat Reclamation Railroad Avenue - 192s Railroad Avenue -

types - Timber pile-supported relieving platform (2) -

$1.4 million Type B Seawall Section Type B Seawall Section

13 Tideflat Reclamation Railroad Avenue - 192s Railroad Avenue - 192s Seattle Seawall 12, 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 Section Type B Seawall Section Precast Section Timber Relieving Platfor Master Pile Vertical Piles (6) Batter Piles (12

-16 Pile/Platform Connection Seawall Construction Seawall Construction 38 37 Type A Seawall Section 14 Type A Seawall Section 6 5 4 3 2 H-4-93 B-7 1-1 -2-3 -4-5 -6-7 -8-9 H-34-96 4 8 2 5/3" 65 18 24

29 28 2726 2524 23 22 21 2 19 18 17 16 1514 13 12 11 1 9 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 9 1 11 12 22 21 2 19 18 17 16 1514 13 12 11 1 9 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 9 1 11 12 1314 15 16 17 18 19

14 -16 Pile/Platform Connection Seawall Construction Seawall Construction Type A Seawall Section 14 Type A Seawall Section H-4-93 B H /3" B /3" (ON ROCK) 5/3" 5/5" 5/4" TILL /6" 65/6" 47 5/2" 25 TILL 15/9" 1/24" 1/18" 1/4" /1" 97/9" MS JOB S.R. C.S. C L B-2, B-7 AND B-8 C L ALASKAN WAY VIADUCT Pile-Supported Concrete Wall Section Fill and Rip Rap Wall Section FIGURE 4: SECTION C - C' ALASKAN WAY VIADUCT WASHINGTON STATE DATE FEB TRANSPORTATION COMMISSION SCALE 1"=4' VERT. DEPARTMENT OF TRANSPORTATION 1"=4' HORIZ. MATERIALS BRANCH SHEET 1 OF 2 D. C. JACKSON MATERIALS ENGINEER DRAWN BY LSH WATER LINE 1.25:1 TILL 27' NW R-3 R /18" CPT 38 3' NW R Qc (tsf) 15' SE /1" 65/6" /2" R ' NW 1 H ' NW H B-7 7 B-2 3 1/6" /18" 13 1/12" 28 1/24" Hole terminated due to 51/6" 37 TILL contaminated soil /6" 4 84/6" TILL /4" 78/6" 115' NW R /6" /4" 5/3" 5/6" 47 88/11" 5/5" /6" 5/4" WATER LINE TILL ' NW R FILL :1 2 ' ' NW TILL R-3 R /18" 154' NW CPT ' NW 5 Qc (tsf) R /1" 65/6" /2" 85' SE R /6" 51 6/6" 84/6" H ' NW TILL 25' SE H /6" 4 2/18" 1/12" 1/24" Hole terminated due to contaminated soil

15 Alaskan Way Viaduct Typical Elevation (WSDOT Section) History -Originally intended as downtown bypass - Design began in 1948, bids opened Seattle section opened April 4, WSDOT section opened Sept 3, Seneca Street off-ramp opened Columbia Street on-ramp opened 1966 Facts - 7,6 ft long - 58,867 yards of concrete, 7,46 tons of rebar - 171,41 ft of piling 57 ft 7 ft 57 ft 22 ft 36 ft Typical Interior Bent (WSDOT Section) Foundations 47 ft 22 ft 36 ft WSDOT Section Seattle Section Foundations Seattle Section WSDOT Section Originally intended to u only H-piles Contractor requested change Steel piles - 48 tons All other piles - 4 tons Seattle Section WSDOT Section

Seattle Section WSDOT Section Originally intended to u only H-piles Contractor requested change Steel piles - 48 tons All other piles - 4 tons Subsurface Data 5 shallow borings by SED in 1948 17 deep

16 Seattle Section WSDOT Section Originally intended to u only H-piles Contractor requested change Steel piles - 48 tons All other piles - 4 tons Subsurface Data 5 shallow borings by SED in deep borings by WSDOH in mid-195s Blanchard Stewart St. University St. Columbia St. Various borings by others Yesler Way 8 borings with SPT 16 CPT soundings with seismic cone 2 deep borings with downhole seismic S. Royal Brougha Way S. Massachusetts Subsurface Profile Uncorrected SPT Resistance Elevation (ft) 1 5 Elevaion (ft) -5-1 Blanchard Stewart 1 ft University Yesler Waterfront Fill Tideflat Deposit Till Royal Brougham Massachusetts Depth (ft) Standard Penetration Resistance (blows/ft) Existing Data Supplemental Subsurface Investigation -15 Input Motions PSHA (1% in 5 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 Acceleration (g).5 Ground Surface Motions Time (sec) Time (sec) Acceleration (g) Acceleration (g) Acceleration (g) ft soft soil 5 ft soft soil 1 ft soft soil

Liquefaction Susceptibility Mabey and Youd (1991) Historical evidence - Sand boils in 1949 and 1965 - Broken pipes in 1949 and 1965 - Lateral movements in 1965 Construction techniques - Hydraulic

) >1 14-1 84-1 6-48 45-84 2-12 1-45 - 4 Little liquefaction susceptibility but in areas with steep slopes. Liquefaction is unlikely, but if it were to occur, large displacements are possible.

17 Liquefaction Susceptibility Mabey and Youd (1991) Historical evidence - Sand boils in 1949 and Broken pipes in 1949 and 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 a max.3 g.15 g Displacement (in.) > 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. Liquefaction Evaluation Standard Penetration Test Liquefaction Evaluation Standard Penetration Test Depth (ft) (N 1 ) (N ) 1 6 required to prevent liquefaction Depth (ft) (N ) (N 1 ) 6 1 required to prevent liquefaction SPT-Based Factor of Safety FS L Liquefaction Evaluation Liquefaction Evaluation Comparison with 1965 observations (N 1 ) Depth (ft) 3 4 Depth (ft) 1 Design-level ground motion

18 Liquefaction Evaluation Comparison with 1965 observations Liquefaction Evaluation Comparison with 1965 observations Depth (ft) (N ) ground motion Design-level ground motion Depth (ft) (N ) 1 6 Design-level ground motion Liquefaction Evaluation Comparison with 1965 observations Depth (ft) (N ) ground motion Design-level ground motion SPT-Based Factor of Safety Depth (ft) FS L ground motion Effects 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 =.6 - Tips of southernmost piles in liquefiable soil Lateral pile movement - Depends on lateral soil movement expected to cause bending failure - Lateral soil movement depends on seawall movement u All movements variable due to variability of soil profile Seawall Investigation Estimation of permanent deformations due to liquefaction 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 FLAC

FLAC Fast Lagrangian Analysis of Continua Explicit finite difference code

(beams, piles, cables) Interface elements (normal and shear) Coupled

display of results Dynamic option Creep option FISH programming language Type B Wall

Viaduct Type B Wall Model 34 soil elements 61 structural elemen Type B Wall Model

19 FLAC 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 Type B Wall Model Entire Section Alaskan Way Viaduct Type B Wall Model Entire Section Alaskan Way Viaduct Type B Wall Model 34 soil elements 61 structural elemen Type B Wall Model Precast Section Timber Relieving Platform Type B Wall Master Pile Vertical Piles (6) Before liquefaction Batter Piles (12)

20 Type B Wall Type B Wall During liquefaction After liquefaction Fill and Rip Rap Wall Fill and Rip Rap Wall Before liquefaction During liquefaction Fill and Rip Rap Wall Zones of Large Lateral Movements University St. Madison St. Columbia St. After liquefaction S. Washington St.

21 Structural Aspects of Seismic Vulnerability Dynamic Response Spectrum Analyses Nonlinear Pushover Analyses Investigated capacities and demands for: - Flexure (beams and columns) - Shear (beams and columns) - Splices - Joints - Pile Caps Capacity/Demand Ratios Exterior Frame - Column Flexure Capacity/Demand Ratios Interior Frame - Column Flexure Capacity/Demand Ratios Longitudinal Frame - Column Flexure Capacity/Demand Ratios Pile Caps Splices.2 Interior Frame Exterior Frame.3 Flexural Capacity - OK Shear Capacity Insufficient (C/D =.3 -.6).1.12 Anchorage Capacity - Insufficient Joint Capacity Insufficient (C/ =.6-1.2)

22 Summary of Structural Vulnerability Lower-level splices highly vulnerable Joints highly vulnerable Columns - shear capacity marginal Footings - vulnerable to brittle failure Special sections require additional investigation - Outrigger bents - On/off ramp sections Summary of Structural Vulnerability Lower-level splices highly vulnerable Joints highly vulnerable Columns - shear capacity marginal Footings - vulnerable to brittle failure Special sections require additional investigation - Outrigger bents - On/off ramp sections Effects of liquefaction-induced lateral soil movements will dominate effects of shaking

Liquefaction and Foundations

Liquefaction and Foundations Amit Prashant Indian Institute of Technology Gandhinagar Short Course on Seismic Design of Reinforced Concrete Buildings 26 30 November, 2012 What is Liquefaction? Liquefaction