NC Experience with MEPDG, LCCA and Alternate Bidding for Pavements January 2012 Ellis Powell, PE Director of Technical and Regulatory Services Carolina Asphalt Pavement Association
NC Experience with MEPDG, LCCA and Alternate Bidding for Pavements
January 2012Ellis Powell, PE
Director of Technical and Regulatory ServicesCarolina Asphalt Pavement Association
MEPDG in NC• NCDOT hired a professor to do NC specific calibration• More work is being done regarding the calibration of individual vs combined layers for asphalt
• The new software is installed at NCDOT and designers are being trained
• Error in the thermal coefficient of expansion, greatly effects concrete design, will take 12‐15 months to correct
• FHWA is offering webinars after TRB• NCDOT is proceeding in a conservative manner
Alternate Bidding Conception(NCTA Projects)
• Dissatisfaction regarding the project approach led to alternate bidding development
• A Loop (12.5 miles) and an Expressway (3.5 miles)• Loop is Concrete and Expressway is Asphalt • NCTA made pavement decisions prior to RFP, not alternate bids
• Neither Industry satisfied with process• Both Industries went to NCTA together to request an Alternate Bidding Process
• Both industries agreed to let the numbers determine the outcome per project
Alternate Pavement Bidding and LCCA Specification
• Alternate Pavement Bidding with LCCA began with the NCTA
• NCTA trying to develop a specification for Alternate Pavement Bidding
• At the time NCTA was a separate entity from NCDOT• At CAPA’s request NCDOT became involved with the development of the specification
• NCTA later became a part of NCDOT
Alternate Pavement Bidding andLCCA Specification Continued
• Workgroup was created to develop the new specification
• Both Asphalt and Concrete Pavement Industry are members of the workgroup
• Have been working on the issue for two years without resolution
• Sticking points are the design term, the term of the LCCA, maintenance and rehab details, and ride quality requirements
• Even without resolution projects have been let and awarded with Alternate Pavement Specifications
Workgroup Efforts
• Both industries agreed to work together on the process
• Worked through minor issues easily• Sticking points caused the process to stall• Concrete industry decided to take their concerns to the legislature
Asphalt Industry Position
• LCCA Period of 40‐50 years and include a major rehab/reconstruction cycle
• Asphalt Pavement design period of 20 years• Mill and fill at 15 and 30 years• 4% discount rate• Ride specification should be the same for both
Concrete Industry Position• LCCA period of 40‐50 year and include a major rehab/reconstruction cycle
• 30 year design period for both pavements• Patch concrete at year 20• Diamond grind, reseal and patch at years 35 and 50 with no overlay
• Eliminate AC price adjustment for asphalt pavement
• Disparity in thickness specifications
Concrete Industry Continued
• Shoulder types need to be included• Inflation rates are different and therefore the discount rates should be different
• Recommend consider short and long term rates• Recommend utilizing a 5% to 10% remaining life value at the end of the LCCA period
• IRI for concrete should be greater than asphalt
Resolution Effort• NCTA met with separately with each industry and then jointly to try to resolve differences
• No resolution was reached • NCTA hires firm to determine proper resolution details
• Concrete industry goes to legislature claiming NCTA/NCDOT unfair
Alternate Pavement Project• LCCA in limbo, another project must go forward• Monroe Bypass alternate pavements • Prescribed designs for each pavement type• Initial designs based upon AASHTO 72 Design Guide• Concrete Industry lobbied to use MEPDG• CAPA lobbied to use AASHTO 93 Design Guide• NCTA used AASHTO 72 Design Guide and 30 year design for both pavements in final RFP
• Also allowed ATC
Original 20 Year Asphalt & 30 Year Concrete Design
20 year Asphalt• Alt. 1, 3” surface, 4”
intermediate, 11” base, stab. Subgrade, (18” total)
• Alt. 2, 3” surface, 4” intermediate, 6.5” base, 10”ABC, (23.5” total)
• Alt. 3, 3” surface, 4” intermediate, 5” base, 8” CTACB, stab. Subgrade, (20” total)
30 year Concrete• 13.5” concrete• 3” PADL• 1.25” asphalt layer• stab. Subgrade• 17.75” total
Final 30 year Asphalt& 30 Year Concrete Design
30 year Asphalt • Alt. 1, 3” surface, 4”
intermediate, 12.5” base, stab. Subgrade, (19.5” total)
• Alt. 2, 3” surface, 4” intermediate, 8” base, 10” ABC, stab. Subgrade, (25”total)
• Alt. 3, 3” surface, 4” intermediate, 6.5” base, 8” CTABC, (21.5” total)
30 year Concrete• 13.5” concrete• 3” PADL• 1.25” asphalt layer• Stab. Subgrade• 17.75” total
Alternate Pavement Project• Monroe Bypass ‐ 20 mile project• Design Build • Choice of pavement types• Bid head to head without LCCA• 4 design build teams• 3 used concrete one used asphalt• Asphalt won by $34 million• Winning team used ATC
Winning Team Design• Original Designs in RFP were 72 design guide• Winning Team submitted design based upon 93 design guide through the ATC process
• Winning Design is: 3” surface, 5” intermediate and 10” CATABC (17” total)
• This design saved $16 million compared to the RFP design
Concrete Industry Efforts• Concrete industry continues to claim NCDOT is unfair in pavement type selections
• Concrete Industry lobbied for LCCA legislation• Drafted Legislation requiring MEPDG, 30 year LCCA period and pavement selection on results
• Lobbied for more concrete pavements
CAPA Efforts• Worked with other partner associations to support NCDOT – very effective
• CAPA, AGC, Aggregate Association, Professional Engineers and Consulting Engineers all lobbied legislature to refrain from legislating engineering decisions
• All supported NCDOT in making appropriate engineering decisions
• All partner associations lobbied for more transportation funding not more market share
• Issue is ongoing
Lessons Learned • Asset management data does not represent current improved asphalt mix designs
• DOT views information from NAPA and NCAT as biased
• Lobby the legislature with partners AGC, Aggregate and Engineering Associations for more transportation funding and not to legislate engineering decisions
Lessons Learned • DOT wants competition• DOT wants the legislature to stay out of the engineering process
• LCCA should be determined prior to developing an alternative pavement specification
• Reach out to NAPA, APA, AI and SAPA to assist
Current NC Status• Legislature initiated a study bill and formed a group to study LCCA at NCDOT
• NCDOT has hired a firm to review data and determine the proper LCCA details
• Christie Barbee is at the legislature today making a presentation indicating the Asphalt industry position on LCCA.