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Advanced Grading Techniques for Contractors

Explore top contractor best practices in grading with H. B. Rowe & Co., Inc., covering 2D, 3D, manual, sonic, GPS, and robotic grading methods. Learn essential tips and techniques for quality assurance and precision in heavy highway and site development projects.

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Advanced Grading Techniques for Contractors

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  1. AFB80 Session 404January 12, 2009 Contractor Best Practices Transportation Research Board Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  2. H. B. Rowe & Co., Inc. • Founded in 1946 • Heavy Highway / Site Development • Licensed in North Carolina, South Carolina, and Virginia Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  3. Slope Stakes Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  4. Grade Stakes (Blue Tops) Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  5. Natural Ground Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  6. 2-D Rough Grading Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  7. 2-D Rough Grading Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  8. 3D Rough Grading Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  9. Bubba’s Rule of Precision • Measure it with a micrometer • Mark it with chalk • Cut it with an axe Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  10. 2D Operator View Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  11. 2-D Manual Grading • Manual control of machine • Quality – skill of operator and checker • Grade along profile between stations? Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  12. Manual Best Practices • Guard stakes adjacent to grade hubs • Notch or Nail grade and correction • Visually mark super-elevation changes • Stay one station ahead of grader Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  13. Maximum SAG crown String Sag • Can easily “check” out of tolerance • Lower and inconsistent string pull • Length on multi-lane can exceed 70 ft • SAG 0.19 ft - Pull 20 lb, String 0.1oz/ft Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  14. Quality Assurance Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  15. 2.5D Sonic Grading • Partial vertical automation • Changes in super-elevation - manual • Grade along profile maintained Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  16. Sonic Best Practices • Steel pins set at Grade Hubs, add 1 ft • String runs 1,000 feet or less • Visually indicate super changes • Complete first pass on string • Calibrate – Cutting edge & tire change • Paint crown and shoulder breaks Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  17. Quality Assurance What happens between stations? Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  18. Surveying “thought I was wrong once but I was mistaken” Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  19. 3D vs Grade Stakes • Assume a interstate project 8.3 km • Grade Stakes every 20 m (4 per station) VS Control Stakes every 320 m 1660 Grade Stakes VS 26 Control Stakes Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  20. 3D Model Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  21. 3D Operator View Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  22. 3D Plan View Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  23. 3D Cross Section View Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  24. 3D Best Practices • Control - Standard • Control – Use it • Control - Maintain Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  25. 3D GPS Grading • Fully automated vertical control • Cross slope changes automated • Grade “anywhere” Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  26. GPS Best Practices • Fixed base station location • Site Calibration - CONTROL • Check consistency daily • Awareness of paper plans Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  27. Quality Assurance Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  28. 3D Robotic Grading • Highly accurate, robotic location Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  29. Robotic Best Practices • Grade Control every 1,000 ft • Establish error limits for set-up • Always measure/update blade wear • Don’t pretend to be a surveyor • Level the mast when benching Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  30. Quality Assurance Need a more advanced string! Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  31. Bubba’s Rule Reversed • Cut it with a laser • Mark it with your thumb • Measure it with a string Forget about sag, just cut out the crown… Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

  32. Conclusion • Technology enables quality and speed • Best Practices key to higher quality • Quality Assurance slow to adopt Contractor Best Practices – H. B. Rowe & Co., Inc. Jan 2009

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