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Rights & Permissions Free PDF Access Sign in to download PDF book and chapters Free Resources Display this book on your site! Related Titles NCHRP Synthesis 428: Practices and Procedures for Site-Specific Evaluations of Earthquake Ground Motions Preventing Earthquake Disasters: The Grand Challenge in Earthquake Engineering:A Research Agenda for the Network for Earthquake Engineering Simulation (NEES) Other Related Titles NCHRP Report 611: Seismic Analysis and Design of Retaining Walls, Buried Structures, Slopes, and Embankments (2009) National Cooperative Highway Research Program (NCHRP) Citation Manager Export the bibliographic data for this book in your chosen format Web Search Builder Use this book's key terms to search within this book, across our collection, or across the Web. Skim This Chapter Skim this chapter and use this chapter's key terms to search within this book. Reference Finder Paste in your own text to find books that relate to your topic. Citation Manager Lam, Ignatius Po, Martin, Geoffrey R, Anderson, Donald G, Wang, Joseph N, Transportation Research Board. "7.5.2 Results of Impedance Contrast and Nonlinearity Evaluations." NCHRP Report 611: Seismic Analysis and Design of Retaining Walls, Buried Structures, Slopes, and Embankments. Washington, DC: The National Academies Press, 2009. Please select a format: Page 79   E-mail Share on facebook Facebook Share on delicious Delicious Share on stumbleupon Stumble Share on twitter Twitter More Sharing ServicesMore Page 79 Front Matter (R1-R10) 1.1 Overall Project Objectives, Approach, and Schedule (1-1) 1.2.1 Plans for Implementing the LRFD Design Methodology (2-3) 1.2.2 Overview of Conclusions from Initial Phase of Work (4-4) 1.2.3 Overview of Conclusions from Second Phase of Work (5-6) 1.2.4 Overview of Conclusions from Third Phase of Work (7-7) 1.3.1 Volume 1 - Final Project Report (8-8) 1.3.2 Volume 2 - Recommended Specifications, Commentaries, and Example Problems (9-9) 2.1 Earthquake Design Basis (10-10) 2.2 Literature Search (11-11) 2.2.1 Key References (12-13) 2.2.2 General Observations (14-14) 2.3 DOT, Vendor, and Consultant Contacts (15-16) 2.4 Conclusions (17-17) 3.1.1 Gravity and Semi-Gravity Walls (18-20) 3.1.2 MSE Retaining Walls (21-21) 3.2.1 Seismic Considerations for Soil Slopes (22-22) 3.2.2 Seismic Considerations for Rock Slopes (23-23) 3.3 Buried Structures (24-24) 3.4 Conclusions (25-25) 4.1 Developments for Seismic Ground Motions (26-27) 4.2.1 Generalized Limit Equilibrium Analyses (28-28) 4.2.2 Wall Height-Dependent Seismic Coefficient (29-29) 4.3 Developments for Slopes and Embankments (30-30) 4.4.1 Analysis Procedures for TGD (31-32) 4.5 Summary (33-34) 5.1.1 Update to AASHTO Seismic Ground Motion Criteria (35-37) 5.1.2 Range of Ground Shaking Levels in the United States for Referenced Soft Rock (38-38) 5.1.3 Variation in Spectral Shapes for Soil and Rock Sites in WUS versus CEUS (39-40) 5.2.2 Description of Ground Motion Database (41-41) 5.2.4 Microsoft Access Database (42-42) 5.2.7 Newmark Sliding Block Displacement Correlations (43-45) 5.2.8 Comparison Between Correlations (46-47) 5.2.9 Confidence Level (48-48) 5.3 Correlation of PGV with S1 (49-53) 5.4 Conclusions (54-54) 6.1.1 Scattering Analyses for a Slope (55-62) 6.1.2 Scattering Analyses for Retaining Walls (63-65) 6.2 Conclusions (66-67) 7.1 Current Design Practice (68-70) 7.2.1 Seismic Active Earth Pressures (71-72) 7.2.2 Seismic Passive Earth Pressures (73-73) 7.3.2 Results of M-O Analyses for Soils with Cohesion (74-74) 7.3.3 Implication to Design (75-75) 7.5 Height-Dependent Seismic Design Coefficients (76-76) 7.5.1 Evaluation of Impedance Contrasts and Soil Behavior (77-78) 7.5.2 Results of Impedance Contrast and Nonlinearity Evaluations (79-80) 7.6 Displacement-Based Design for Gravity, Semi Gravity, and MSE Walls (81-81) 7.7 Conventional Gravity and Semi-Gravity Walls - Recommended Design Method for External Stability (82-83) 7.8.2 MSE Walls - Design Method for External Stability (84-86) 7.8.3 MSE Walls - Design Method for Internal Stability (87-87) 7.9.1 Nongravity Cantilever Walls (88-90) 7.9.2 Anchored Walls (91-92) 7.9.3 Soil Nail Walls (93-93) 7.10 Conclusions (94-95) 8.1.1 Engineered Slopes and Embankments (96-96) 8.2.1 Limit Equilibrium Approach (97-98) 8.2.2 Displacement-Based Approach (99-99) 8.3 Proposed Design Methodology (100-100) 8.4.1 Problem Description (101-101) 8.5.1 Limit Equilibrium Design Methods (102-102) 8.5.3 Liquefaction Potential (103-103) 8.6 Conclusions (104-104) 9.2 Culvert/Pipe Characteristics (105-105) 9.3 General Effects of Earthquakes and Potential Failure Modes (106-106) 9.3.1 Ground Shaking (107-107) 9.4 Current Seismic Design Practice for Culverts or Other Buried Structures (108-108) 9.5.1 Ovaling of Circular Conduits (109-112) 9.5.2 Racking of Rectangular Conduits (113-114) 9.6.2 Model Assumptions and Results (115-128) 9.7 Conclusions and Recommendations (129-130) 10.2 Retaining Walls (131-131) 10.3 Slopes and Embankments (132-132) 10.5 Need for Confirming Methods (133-133) References (134-136) Appendices (137-137) Abbreviations used without definitions in TRB publications (138-138)

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OCR for page 79
79 Figure 7-15A. SLIDE calibration analyses for sloping backfill (homogeneous soil conditions). contrasts, and accelerations levels, using the same SHAKE 7.5.2 Results of Impedance Contrast models: and Nonlinearity Evaluations · Response evaluated at wall heights of 20, 50, and 100 feet. Results of the studies summarized above and described · The low-strain shear modulus changed to Gmax = 59 ( m) 0.5 in Appendix G generally follow trends similar to the wave to correspond to a relative density of 75 percent, which was scattering studies described in Chapter 6. However, based judged to be more realistic. on a study of the results and to simplify the results for the · Nine ground motions used as noted above. development of recommended specifications and commen-

OCR for page 80
80 Figure 7-15B. SLIDE calibration analyses for sloping backfill (nonhomogeneous soil conditions). taries for the AASHTO LRFD Bridge Design Specifications, Curves in Figure 7-16 from Chapter 6 are for slightly differ- the use of a simple linear function to describe reductions in ent equivalent values than shown for the simplified approach. average height-dependent seismic coefficients, as shown in These values are 1.7, 1.1, and 0.4 for UB, mid, and LB spectral Figure 7-16, is recommended. Comparisons with the curves response, respectively. The differences in the values explain resulting from the height-dependent scattering studies also the difference between the locations of the lines for the curves are noted in Figure 7-16. from Chapter 6 versus the simplified straight-line functions.