N N a a t t i i o o n n a a l l
R R o o u ConcreteConcrete RoundaboutsRoundabouts u n n d d a a b b o o u TRB National Roundabouts Conference u t t
C C o Vail, Colorado o n n f f e e r r e May 22-25, 2005 e n n c c e e
2 2 0 0 0 Steve Waalkes, P.E. 0 5 5
D Managing Director, Technical Services D R R A American Concrete Pavement Association A F F T T N TerminologyTerminology N a a t t i i o o n n a a l l
R R o Concrete Asphalt o u u n n d d a a
b Rigid Flexible b o o u u t t
Uses cement as Uses liquid asphalt as C C o o n binder binder n f f e e r r e Pro: longer lasting Pro: usually lower cost e n n c c e e
Con: higher cost Con: requires frequent 2 2 0 0 0 maintenance & 0 5 5
D rehabilitation D R R A A F F T T N WhyWhy ConcreteConcrete Roundabouts?Roundabouts? N a a t t i i o o n n a a l l
R R o Realize there is a choice o u u n n d d a • Materials a b b o o u u t • Performance (future maintenance) t
C C o o n n
• Economics f f e e r r e e n • Constructability n c c e e
2 2 0 •Safety 0 0 0 5 5
D •Aesthetics D R R A A F F T T N WhyWhy ConcreteConcrete Roundabouts?Roundabouts? N a a t t i i o o n n a a l l
R R o Let’s ask the questions… o u u n n d d a 1. Where do we typically use concrete a b b o o u u t pavement? (situations, traffic t
C C o o n conditions, applications, etc.) n f f e e r r e e n 2. What performance characteristics of n c c e e
2 concrete pavement make it the best 2 0 0 0 0 5 5
choice for roundabouts? D D R R A A F F T T N WhereWhere isis ConcreteConcrete PavementPavement Used?Used? N a a t t i i o o n n a a l l
R Answers: R o o u u n • High traffic areas n d d a a b b o • Areas with lots of turning movements o u u t t
C C
• Situations where we need a “long-term o o n n f f e fix” e r r e e n n c • Situations where future maintenance c e e
2 2 0 must be kept to an absolute minimum 0 0 0 5 5
D • Areas where future disruption to traffic D R R A must be kept to a minimum A F F T • Areas where safety is a priority T N WhyWhy ConcreteConcrete forfor Roundabouts?Roundabouts? N a a t t i i o o n n a a l l
R R o Answers: o u u n n d d a • Long service life a b b o o u u t • Minimal maintenance requirements t
C C o o n n
• Resistance to surface deformation f f e e r r e e n Doesn’t rut or shove n c c e e
2 Maintains drainage characteristics 2 0 0 0 0 5 No future overlays required (grade 5
D D R issues) R A A F F T • Ease of construction (constructability) T N WhyWhy ConcreteConcrete (cont.)(cont.) N a a t t i i o o n n a a l l
R R o o u Answers: u n n d d a a b • Superior safety aspects b o o u u t t
Drainage
C C o o n Skid resistance n f f e e r r e Lighting e n n c c e e
• More aesthetically pleasing 2 2 0 0 0 0 5 • Faster construction 5
D D R R
• Economical over long-term (LCC) A A F F T T N WhyWhy ConcreteConcrete Roundabouts?Roundabouts? N a a t t i i o o n n a a l l
R Concrete is the perfect material for R o o u u n n d roundabout applications. d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T N BenefitsBenefits ofof ConcreteConcrete PavementsPavements N a a t t i i o o n n a a l l
R Strength R o o u u n n d Durability d a a b b o o u Ease of Construction u t t
C C o o n Life Cycle Cost n f f e e r r e e n Lighting/Reflectivity n c c e e
2 2 0
Safety 0 0 0 5 5
D Environmentally Friendly D R R A A F Aesthetics F T T N DesignDesign ofof ConcreteConcrete RoundaboutsRoundabouts N a a t t i i o o n n a a l l
R R o o u u n n
d Thickness Design d a a b b o o u u
t Joint Design t
C C o o n n f • Layout locations f e e r r e e n n c •Allow adjustments c e e
2 2 0 0 0 0 5 Construction 5
D D R R A A F F T T N PavementPavement ThicknessThickness DesignDesign N a a t t i i o o n n a a l l
R R o o u AASHTO u n n d d a a
• 1993 Pavement Design Guide b b o o u u
t Most current t
C C o o n • New Mechanistic-Empirical Design Guide n f f e e r r e Under calibration/implementation e n n c c e e
2 PCA (ACPA) 2 0 0 0 0 5 5
• StreetPave software; will be released Fall D D R R A
2005 A F F T T N JointingJointing forfor ConcreteConcrete RoundaboutsRoundabouts N a a t t i i o o n n a a l l
R Decide on joint layout philosophy R o o u u n n d
• Like normal intersection d a a b b o • Isolate circle from legs o u u t t
C • Pave through, isolate two legs C o o n n f f e e
r Follow 10-step method r e e n n c c e Joints in circular portion radiate from e
2 2 0 0 0 center 0 5 5
D D R Joints in legs are normal (perpendicular) R A A F F T T N LayoutLayout JointsJoints asas NormalNormal N a a t t i i o o n n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A Good for small A F F T roundabouts or T traffic circles? N N a IsolateIsolate CircleCircle fromfrom LegsLegs a t t i i o o n n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F Ideal for large F T roundabouts T with full detour N N a PavePave ThroughThrough a t t i i o o n n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R Ideal for roundabouts R A A F F T requiring fast T construction under traffic N ConcreteConcrete RoundaboutRoundabout JointingJointing N a a t t i i o o n n a a l l
R R o o u u n n d Develop a jointing d a a b b o plan o u u t t
C • Bird’s eye view C o o n n f f e e r Remember rules r e e n n c c e Follow the steps e
2 2 0 0 0 0 5 Be practical! 5
D D R R A A F F T T N TheThe RulesRules ofof JointingJointing N a a t t i i o o n n a a l l
Things to Avoid Things to Do R R o o u • Match existing joints • Slabs < 1 ft (0.3 m) wide u n n d d a or cracks •Slabs > 15 ft (5.0 m) a b b o o u • Cut at the proper wide u t t
C C
time o • Angles < 60º (~90º is o n n f f e • Place joints to meet best) e r r e e n in-pavement Do this by dog-legging joints n c c e through curve radius points e
structures 2 2 0 0 0 • Creating interior corners 0 5
• Understand can 5
D make adjustments • Odd Shapes (keep slabs D R R A A
square or pie-shaped) F
joint location! F T •Be Practical T N RecommendedRecommended Max.Max. JointJoint SpacingSpacing N a a t t i i o o n n a a l l
R 24 x T R o o u u n n d • If concrete placed on unstabilized base (i.e. d a a b b o compacted aggregate or granular base) o u u t t
C C o 21 x T o n n f f e e r r e • If concrete placed on stabilized base (i.e. e n n c c e asphalt- or cement-treated) e
2 2 0 0 0 0 5 5
15 ft absolute maximum for street &
D D R R A highway pavements A F F T T N N a StepStep 11 a t t i i o o n n a a l l
R R o Draw all pavement edge and back-of- o u u n n d d
curb lines in the plan view. a a b b o o u u t t
C C o o n n f f e Draw locations of all manholes, e r r e e n n c drainage inlets, and valve covers so c e e
2 2 0 0 0
that joints can intersect these. 0 5 5
D D R R A A F F T T Natiionall Roundabout Conference 2005 DRAFT N N a StepStep 22 a t t i i o o n n a a l l
R Draw all lane lines on the legs and in the R o o u u n n
circular portion. d d a a b b o • If isolating circle from legs, do not extend these o u u t t
C through the circle. C o o n n f f
• If using “pave-through” method, determine e e r r e e n which roadway will be paved through. n c c e e
2 2 0 0 0 0 5 5
D Make sure no distance is greater than the D R R A A
maximum recommended width. F F T T Natiionall Roundabout Conference 2005 DRAFT N N a StepStep 33 a t t i i o o n n a a l l
R In the circle, add “transverse” joints R o o u u n n
radiating out from the center of the circle. d d a a b b o Make sure that the largest dimension of a o u u t t
C pie-shaped slab is smaller than the C o o n n f f e maximum recommended. e r r e e n n c c e e
2 2 0 0 0 Extend these joints through the back of the 0 5 5
D D
curb & gutter. R R A A F F T T Natiionall Roundabout Conference 2005 DRAFT N N a StepStep 44 a t t i i o o n n a a l l
R On the legs, add transverse joints at all R o o u u n n
locations where a width change occurs in d d a a b b o the pavement (at bullnose of median o u u t t
C islands, begin & end of curves, tapers, C o o n n f f e tangents, curb returns, etc.). e r r e e n n c c e e
2 2 0 0 0 Extend these joints through the back of the 0 5 5
D D
curb & gutter. R R A A F F T T Natiionall Roundabout Conference 2005 DRAFT N N a StepStep 55 a t t i i o o n n a a l l
R Add transverse joints beyond & between R o o u u n n
those added in Step 4. Space joints out d d a a b b o evenly between other joints, making sure to o u u t t
C not violate maximum joint spacing. C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T Natiionall Roundabout Conference 2005 DRAFT N N a StepStep 66 a t t i i o o n n a a l l
R R o Make adjustments for in-pavement o u u n n d d
objects, fixtures, and to eliminate L- a a b b o o u shapes, small triangular slabs, etc. u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T Natiionall Roundabout Conference 2005 DRAFT N N a a t t i i o CaseCase StudyStudy o n n a a l l
R R o o u u n th n d Roundabout at 110 Street & Lamar d a a b b o o u u t
Avenue in Overland Park, Kansas t
C C o o n n f f
• Part of new convention center e e r r e e n n c
(showcase) c e e
2 2 0 0 0 0
National Pavement Award Winner for 5 5
D D R R A Excellence in Concrete Pavements A F F T T RoughRough GradingGrading N N a a t t i i o o n n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T Subgrade preparation & base course N construction complete N a a t t i i o Concrete curb under construction o n n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T N CurbCurb PlacementPlacement –– WidenedWidened GutterGutter N a a t t i i o o n n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T ConcreteConcrete RoundaboutRoundabout N N a a t t
Opened to Traffic i
Opened to Traffic i o o n n a a l l
R R o o u u n n d d a a b b o o u u t t
C C o o n n f f e e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T N MoreMore InfoInfo N a a t t i i o o n n a a l l
R R o o u “Concrete Roundabout Pavements: A u n n d d a a b Guide to their Design and Construction,” b o o u u t t
C
Roads and Traffic Authority, New South C o o n n f f e
Wales, Australia, April 1996. e r r e e n n c c
e Available from: e
2 2 0 0 0 www.bookshop.nsw.gov.au 0 5 5
D D R R A A F F T T N Questions?Questions? N a a t t i i o o n n a a l l
R R o o u u n n d www.pavement.com d a a b b o o u u t [email protected] t
C C o o n n f f e
(847) 966-2272 e r r e e n n c c e e
2 2 0 0 0 0 5 5
D D R R A A F F T T