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Concrete Roundabouts

Concrete Roundabouts. & Intersections. Why Concrete Roundabouts …. No rutting with turning motion of heavy vehicles… Long-term solution… Low maintenance… Good skid resistance… Constructed quickly. Roundabout Issues. Thickness design Joint layout Transitions Staging

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Concrete Roundabouts

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  1. Concrete Roundabouts & Intersections

  2. Why Concrete Roundabouts … • No rutting with turning motion of heavy vehicles… • Long-term solution… • Low maintenance… • Good skid resistance… • Constructed quickly

  3. Roundabout Issues • Thickness design • Joint layout • Transitions • Staging • Opening to traffic

  4. Roundabout Thickness Design • Use existing design procedures • AASHTO 1993 extremely conservative • AASHTO ME • ACPA StreetPave • Design for ALL traffic • Worst case would likely be combined directional traffic from N-1 legs

  5. Follow the Steps • IS006P • Intersection Joint Layout • 10-step method • Available from ACPA • Do not exceed maximum joint spacing at slab exterior for wedge shaped slabs • Use isolation joint at truck apron

  6. Isolate Circle

  7. Pave Through (Not Common)

  8. Narrow Radial Slabs/Truck Aprons

  9. Isolation Joint Narrow Radial Slabs/Truck Aprons

  10. Narrow Slivers

  11. Narrow SliversWidened Gutter

  12. Curb Placement – Widened Gutter

  13. STAGING • Piece meal • Partial Closures • Full Closure

  14. Quadrant Construction

  15. Half at a Time

  16. Production Rate Comparison Fixed Form 12’ Wide 70 – 120 CY/Hr Slip Form Paver 24’ Wide 10”+ depth 200CY-400CY/Hr Reconstruction Mainline New Construction 2500-4000CY/Day

  17. Partial Closure2008 Success Stories • City of Longview Washington • City of Redmond Washington

  18. SR 432 / SR 433PCCP RebuildCity of Longview

  19. Finished Intersection

  20. Intersection Rebuilt in 3 Phases

  21. Ma Bell Vault Work Around

  22. Preformed Traffic Signal Loop

  23. Work was around the Clock

  24. Bull Floating

  25. SR 520 Avondale Rd/Union Hill Rd Redmond WA 100,000 ADT

  26. 100,000 ADT • 2600 CY • Construct in 2 Weekends • Gary Merlino Construction • Consultant Design • INCA Engineers Bellevue

  27. Combination Closures: • SR-395 & Yelm, Clearwater, Kennewick Avenue: • Lane Closures Stages 1,2, 4 • Complete Closure Stage 3, Thursday at 7:00 PM to Monday 6:00 AM. • Late opening penalty of up to $2,400.00 per hour.

  28. Time for Completion: • Kennewick Avenue and Clearwater were built concurrently. This saved a considerable amount of time. Crews always had a place to work. • In 15 days approximately 3384 cubic yards were placed in the two intersections. • Construction staging was as follows:

  29. Kennewick Avenue Stage 1:

  30. Kennewick Avenue Stage 2:

  31. Kennewick Avenue Stage 3:

  32. Kennewick Avenue Stage 4:

  33. Photo Stage 4:

  34. Crater Lake & McAndrewsMedford, OR

  35. Crater Lake & McAndrews • 60,000 ADT • Widening work done prior to any traffic modifications • Closed half of the intersection for 1 week • Total 2 weeks to complete

  36. Construction Time • 70 – 120 cy/hr typical for hand placement • 2 lane roundabout , 80’ dia., could be paved in 7-10 days under complete closure

  37. Opening Strength • Acceptable opening strength dependent on slab thickness • 7” 370 psi = 2,040 psi compressive • 8” 335 psi = 1,760 psi compressive • 9” 275 psi = 1,310 psi compressive • 10” 200 psi = 820 psi compressive • Based on FE analysis assuming 1000 trucks per day, k-value of 200 pci, no edge support. • Beam strength typically lower than in-place strength by 50-150 psi

  38. Reasons for Success: • WSDOT had several preliminary meetings with City of Kennewick to discuss impacts and City concerns. • WSDOT invited businesses to pre construction meeting. • WSDOT met with contractors to discuss feasibility. • WSDOT kept public informed via newspaper, radio, and television news broadcasts. • WSDOT web page with up to date information. • WSDOT gave flyers to businesses weekly.

  39. Reasons for Success Continued: • WSDOT/Acme partnered on the modifications to the traffic control plan allowing continuous work operation with increased safety for employees. • Clearwater & Kennewick were constructed concurrently maximizing crew efficiency. • Detailed schedule with known milestones. • Meeting or beating schedule. • Something going on all the time. • Decision makers available to resolve issues.

  40. Keys to SuccessAll Projects • Adequate time for planning • Industry Input • Qualified Contractor • Just in Time Training • Timely Decision Making • REALISTIC SPECIFICATIONS

  41. Thank you! Questions?

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