Final Research Report Agreement T2695, Task 66 Liquefaction Phase III EVALUATION OF LIQUEFACTION HAZARDS IN WASHINGTON STATE WA-RD 668.1 Professor Steven L. Kramer December 2008 University of Washington WSDOT Research Report Office of Research & Library Services Final Research Report Agreement T2695, Task 66 Liquefaction Phase III EVALUATION OF LIQUEFACTION HAZARDS IN WASHINGTON STATE By Steven L. Kramer Professor Department of Civil and Environmental Engineering University of Washington, Box 352700 Seattle, Washington 98195 Washington State Transportation Center (TRAC) University of Washington, Box 354802 1107 NE 45th Street, Suite 535 Seattle, Washington 98105-4631 Washington State Department of Transportation Technical Monitor Tony Allen Chief Geotechnical Engineer, Materials Laboratory Prepared for Washington State Transportation Commission Department of Transportation and in cooperation with U.S. Department of Transportation Federal Highway Administration December 2008 TECHNICAL REPORT STANDARD TITLE PAGE 1. REPORT NO. 2. GOVERNMENT ACCESSION NO. 3. RECIPIENT'S CATALOG NO. WA-RD 668.1 4. TITLE AND SUBTITLE 5. REPORT DATE EVALUATION OF LIQUEFACTION HAZARDS IN December 2008 WASHINGTON STATE 6. PERFORMING ORGANIZATION CODE 7. AUTHOR(S) 8. PERFORMING ORGANIZATION REPORT NO. Steven L. Kramer 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. WORK UNIT NO. Washington State Transportation Center (TRAC) University of Washington, Box 354802 11. CONTRACT OR GRANT NO. University District Building; 1107 NE 45th Street, Suite 535 Agreement T2695, Task 66 Seattle, Washington 98105-4631 12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED Research Office Final Research Report Washington State Department of Transportation Transportation Building, MS 47372 Olympia, Washington 98504-7372 14. SPONSORING AGENCY CODE Kim Willoughby, Project Manager, 360-705-7978 15. SUPPLEMENTARY NOTES This study was conducted in cooperation with the U.S. Department of Transportation, Federal Highway Administration. 16. ABSTRACT This report describes the results of a detailed investigation of improved procedures for evaluation of liquefaction hazards in Washington State, and describes the development and use of a computer program, WSliq, that allows rapid and convenient performance of improved analyses. The report introduces performance-based earthquake engineering (PBEE) concepts to liquefaction hazard evaluation. PBEE procedures have been developed and implemented for evaluation of liquefaction potential, lateral spreading displacement, and post-liquefaction settlement. A new model for estimation of the residual strength of liquefied soil was also developed. The WSliq code was developed to have broad capabilities for evaluation of liquefaction susceptibility, liquefaction potential, and the effects of liquefaction. It provides new methods for dealing with the magnitude-dependence inherent in current procedures, and makes the common “magnitude selection” problem moot via a new multiple-scenario approach and through the use of PBEE procedures. 17. KEY WORDS 18. DISTRIBUTION STATEMENT Earthquake engineering, liquefaction, lateral No restrictions. This document is available to spreading, settlement, residual strength, response the public through the National Technical spectrum, performance-based engineering Information Service, Springfield, VA 22616 19. SECURITY CLASSIF. (of this report) 20. SECURITY CLASSIF. (of this page) 21. NO. OF PAGES 22. PRICE None None DISCLAIMER The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Washington State Transportation Commission, Washington State Department of Transportation, or Federal Highway Administration. This report does not constitute a standard, specification, or regulation. iii iv CONTENTS Chapter 1 Evaluation of Liquefaction Hazards in Washington State ................ 1 1.1 Introduction ................................................................................................ 1 1.2 Soil Liquefaction............................................................................................ 2 1.2.1 Terminology....................................................................................... 5 1.2.2 Background........................................................................................ 6 1.3 Organization of Manual ................................................................................. 7 Chapter 2 Earthquake Ground Motions in Washington State............................ 9 2.1 Introduction ................................................................................................ 9 2.2 Earthquake Sources........................................................................................ 9 2.3 Ground Motions............................................................................................. 11 2.3.1 PSHA-Based Ground Motions........................................................... 12 2.4 Implications for Liquefaction Hazard Evaluation ......................................... 19 Chapter 3 Performance Requirements .................................................................. 20 3.1 Introduction ................................................................................................ 20 3.2 Randomness and Uncertainty ........................................................................ 21 3.3 Treatment of Uncertainties in Liquefaction Hazard Evaluation.................... 22 3.3.1 Historical Treatment .......................................................................... 22 3.3.2 Current Treatment.............................................................................. 23 3.3.2.1 PSHA-Based Loading............................................................ 23 3.3.2.2 Resistance.............................................................................. 24 3.3.3 Emerging Treatment .......................................................................... 25 3.3.4 Model Uncertainty............................................................................. 26 3.4 The Magnitude Issue...................................................................................... 26 3.4.1 Single-Scenario Approach................................................................. 28 3.4.2 Multiple-Scenario Approach.............................................................. 28 3.4.3 Performance-Based Approach........................................................... 29 3.4.4 Recommendations.............................................................................. 29 3.5 Performance Criteria...................................................................................... 30 3.5.1 Conventional Analyses...................................................................... 30 3.5.2 Performance-Based Analyses............................................................ 31 Chapter 4 Susceptibility to Liquefaction............................................................... 32 4.1 Introduction ................................................................................................ 32 4.2 Deposit-Level Susceptibility Evaluation ....................................................... 33 4.2.1 Liquefaction History Factor............................................................... 34 4.2.2 Geology Factor.................................................................................. 35 4.3.2 Compositional Factor......................................................................... 37 4.3.2 Groundwater Factor........................................................................... 38 4.3 Examples ................................................................................................ 39 Example 1: Sodo District, Seattle.................................................................. 39 Example 2: Andresen Road Interchange, Vancouver.................................... 40 v Example 3: Capitol Boulevard Undercrossing, Olympia .............................. 41 Example 4: Yakima River Site ...................................................................... 42 Example 5: Bone River Site........................................................................... 43 4.4 Layer-Level Susceptibility Evaluation .......................................................... 43 4.4.1 Boulanger and Idriss (2005) .............................................................. 44 4.4.2 Bray and Sancio (2006) ..................................................................... 46 4.4.3 Discussion.......................................................................................... 48 4.5 Susceptibility Index....................................................................................... 49 4.5.1 Combination of SBI and SBS ................................................................ 49 4.5.2 Effects of Parametric Uncertaintey.................................................... 50 4.6 Recommendations.......................................................................................... 52 4.7 Examples ................................................................................................ 53 Chapter 5 Initiation of Liquefaction ...................................................................... 55 5.1 Introduction ................................................................................................ 55 5.2 Background ...............................................................................................