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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 Report 682: Scour at Wide Piers and Long Skewed Piers NCHRP Report 515: Portable Scour Monitoring Equipment Other Related Titles NCHRP Report 516: Pier and Contraction Scour in Cohesive Soils (2004) 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 Wang, J, Briaud, J-L, Li, Y, Chen, H-C, Nurtjahyo, P, Transportation Research Board. "10.5 Remarks." NCHRP Report 516: Pier and Contraction Scour in Cohesive Soils. Washington, DC: The National Academies Press, 2004. Please select a format: Page 88   E-mail Share on facebook Facebook Share on delicious Delicious Share on stumbleupon Stumble Share on twitter Twitter More Sharing ServicesMore Page 88 Front Matter (R1-R10) Summary (1-7) 1.4 Why Was This Problem Addressed? (8-8) 1.5 Approach Selected to Solve the Problem (9-9) 2.4 Erodibility and Correlation to Soil and Rock Properties (10-13) 3.3 EFA Test Data Reduction (14-14) 3.4 EFA Precision and Typical Results (15-16) 4.2 Small Flood Followed by Big Flood (17-17) 4.3 Big Flood Followed by Small Flood and General Case (18-18) 4.4 Hard Soil Layer Over Soft Soil Layer (19-20) 4.6 Equivalent Time (21-21) 4.7 Extended and Simple SRICOS-EFA Method (22-23) 4.8 Case Histories (24-25) 4.9 Predicted and Measured Local Scour for the Eight Bridges (26-28) 4.10 Conclusions (29-29) 5.4 Measuring Equipment (30-31) 5.5 Soils and Soil Bed Preparation (32-32) 5.6 Flume Tests: Procedure and Measurement (33-33) 5.8 Shallow Water Effect on Maximum Pier Scour Depth (34-35) 5.9 Shallow Water Effect on Initial Shear Stress (36-36) 5.11 Pier Spacing Effect on Maximum Scour Depth (37-37) 5.12 Pier Spacing Effect on Initial Scour Rate (38-38) 5.15 Pier Shape Effect on Initial Scour Rate (39-39) 5.18 Attack Angle Effect on Maximum Scour Depth (40-41) 5.20 Attack Angle Effect on Scour Hole Shape (42-42) 5.21 Maximum Scour Depth Equation for Complex Pier Scour (43-44) 6.2 Existing Knowledge on Numerical Simulations for Scour (45-45) 6.5 Shallow Water Effect: Numerical Simulation Results (46-46) 6.6 Shallow Water Effect on Maximum Shear Stress (47-47) 6.7 Pier Spacing Effect: Numerical Simulation Results (48-48) 6.9 Pier Shape Effect: Numerical Simulation Results (49-50) 6.10 Pier Shape Effect on Maximum Shear Stress (51-51) 6.11 Attack Angle Effect: Numerical Simulation Results (52-52) 6.12 Attack Angle Effect on Maximum Shear Stress (53-53) 6.13 Maximum Shear Stress Equation for Complex Pier Scour (54-55) 7.3 Flume Tests and Measurements (56-56) 7.4 Flume Tests: Flow Observations and Results (57-58) 7.5 Flume Tests: Scour Observations and Results (59-59) 7.6 Maximum and Uniform Contraction Depths for the Reference Cases (60-62) 7.7 Location of Maximum Contraction Depth for the Reference Cases (63-63) 7.8 Correction Factors for Transition Angle and Contraction Length (64-64) 7.9 SRICOS-EFA Method Using HEC-RAS Generated Velocity (65-65) 7.11 Scour Depth Equations for Contraction Scour (66-67) 8.3 Transition Angle Effect: Numerical Simulation Results (68-68) 8.4 Contracted Length Effect: Numerical Simulation Results (69-71) 8.6 Maximum Shear Stress Equation for Contraction Scour (72-75) 9.3 The Integrated SRICOS-EFA Method: Step-by-Step Procedure (76-80) 9.5 The SRICOS-EFA Program (81-83) 9.6 Output of the SRICOS-EFA Program (84-84) 10.4 Gill (1981) Database: Contraction Scour (85-87) 10.5 Remarks (88-88) 11.2 Preparation of the Future Hydrographs (89-89) 11.3 Risk Approach to Scour Predictions (90-90) 11.4 Observations on Current Risk Levels (91-92) 12.2 Example 2: Single Rectangular Pier with Attack Angle and Approaching Hydrograph (93-94) 12.3 Example 3: Group Rectangular Piers with Attack Angle and Approaching Constant Velocity (95-98) 12.4 Example 4: Contracted Channel with 90-Degree Transition Angle and Approaching Constant Velocity (99-102) 12.5 Example 5: Contracted Channel with 60-Degree Transition Angle and Approaching Hydrograph (103-104) 12.6 Example 6: Bridge with Group Piers and Contracted Channel with Hydrograph in Contracted Section (105-110) 13.1 Conclusions (111-112) 13.2 Recommendations, (113-113) References (114-115) Nomenclature (116-117) Unit Conversions (118-118) Appendix A - Photographs from the Flume Tests (119-125) Abbreviations used without definitions in TRB publications (126-126)

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88 SRICOS-EFA Method HEC-18 Method (Gill Database) (Gill Database) 55 55 50 50 Predicted Scour Depth (mm) 45 45 Predicted Scour Depth (mm) 40 40 35 35 30 30 25 25 20 20 15 15 10 10 5 5 0 0 0 5 10 15 20 25 30 35 40 45 50 55 0 5 10 15 20 25 30 35 40 45 50 55 Measured Scour Depth (mm) Measured Scour Depth (mm) Figure 10.7. SRICOS-EFA Method against Gill (1981) Figure 10.8. HEC-18 Method against Gill (1981) Database. Database. 1 1 10.5 REMARKS Vc = 6.19 y 6 D50 3 (10.1) While it would have been preferable to find a number of full-scale case histories, at least the comparison to databases where Vc is the critical velocity of the bed material, m/s; y is obtained primarily on cohesionless soils gave an idea of how the water depth in the upstream flow, m; and D50 is the parti- the SRICOS-EFA Method compares to the HEC-18 Method. cle corresponding to 50% passing by weight, m. Figure 10.7 Note that the comparison is only based on the maximum depth shows the comparison between the uniform contraction scour of scour values and does not involve the scour rate, which is the depth calculated by the SRICOS-EFA Method and the mea- major difference between the current HEC-18 Method and the surements in the database. Figure 10.8 shows the HEC-18 SRICOS-EFA Method. Overall, it was found that the perfor- equation compared with the same database. As shown, the mance of the SRICOS-EFA Method is similar to the HEC-18 SRICOS Method is reasonably good, but the HEC-18 Method Method except for the contraction scour depth where the is severely under predicting. SRICOS-EFA Method is much closer to the measurements.