Embed Size (px)
Citation preview
Lonnie Burklund, PE, PTOEManager, Traffic Engineering
City of Lincoln, NEPublic Works Dept.
mobile: 402-416-1357 E-Mail: [email protected]
Roundabout Paving
Roundabouts
Roundabouts
Roundabouts
Roundabouts
Roundabouts
Roundabouts
Roundabouts
Roundabouts
Roundabouts
Roundabouts
Better Choice of Intersection Control
Roundabouts
Lincoln is Building More Roundabouts• 30 – 50% increase in traffic capacity• 40% reduction in all crash types• 75% reduction in injury crashes• 90% reduction in fatal crashes• 40% reduction in ped crashes• Reduced Costs (Life Cycle)
Better Choice of Intersection Control
Roundabouts
Lincoln is Building More Roundabouts• Fewer conflict points (16 vs. 56)• Speed differential minimized• Short ped crossings• No red light running• No signal equipment
Better Choice of Intersection Control
Conflict Comparison (16 vs 56)
Roundabouts
Geometric Design - Construction Impacts• Design Vehicles – Radii, Truck Aprons• Left-of-Center Approach• Curbs, Islands, Layout• Alignment, Joints
“It’s a CURVY World
Roundabout Paving
Concrete Pavement is Good• High Traffic Areas• Lots of Turning Movements• Long Service Life• Resistance to Deformation
Doesn’t rut or shoveMaintains drainage
Roundabout Paving
Proper Jointing is Key• Control Natural Transverse & Longitudinal
Cracking from Internal Slab Stresses• Divide Pavement into Construction Lanes• Accommodate Slab Movements• Provide Load Transfer• Provide Uniform Sealant Reservoir
Roundabout Paving
Roundabout Joints
Roundabout Paving
Roundabout Joints
Roundabout Paving
Do:• Match Existing Joints• Place Joints to Meet
Structures• Be Mindful of Max
Joint Spacing• Place Isolation Joints• Make Field
Adjustments if Needed• Be Practical
Avoid:• Slabs < 2ft wide• Slabs > 15ft wide• Angles < 60 deg• Creating Interior
Corners• Odd Shapes (keep
square or pie shaped
Roundabout Paving
Joint Layout Design Options• Isolate Circle from Approaches
Joints in circle radiate from centerJoints on approach are standard (perp)
• Pave ThroughIsolate two legsJoints are standard (perp)
• PinwheelDirects motorists to exit, or remain inside
Roundabout Paving
Joint Layout Design Options• Isolate Circle from Approaches
Roundabout Paving
Joint Layout Design Options• Pave Through
Roundabout Paving
Joint Layout Design Options• Pinwheel
Roundabout Paving
Lincoln Roundabouts
Roundabout Paving
Lincoln Roundabouts
Roundabout Paving
Lincoln Roundabouts
Roundabout Paving
Lincoln Roundabouts
Roundabout Paving
Lincoln Roundabouts
Roundabout Paving
Lincoln Roundabouts
Roundabout Paving
Lincoln Roundabouts
Roundabout Paving
Key Elements - Concrete Roundabouts• Choose Joint Layout Philosophy• Preliminary Joint Layout• Joints Meet Pavement Edges Near 90 deg
Dogleg joints within 2-3’ of an edge• Adjust Joints (manholes, inlets, etc.)
Isolation joints• Consider Construction Phasing• Allow Further Field Adjustment
Roundabout Paving
Medians / Curbs / Islands• Truck Apron – stamped concrete• 4” Integral Curbs (mountable)• Thickened edges, noses
Roundabout Paving
Medians / Curbs / Islands
Roundabout Paving
New Projects – Fringe
Built Environment
Single-Lane, Multi-Lane
Roundabout Paving
THANK YOU!!
