FAA Eastern Region 34 th Annual Airport Conference March 2, 2011 – Hershey, PA

Rehabilitation Requirements of these intersections result from general usage and time The layout of many Cross Wind Runways include an Intersection

 Pavement Rehabilitation is required when deficiencies are indicated  Structural Requirement  Functional Requirement  Grade and Profile “Correction” is REVIEWED through intersections when evaluating the pavement rehabilitation project  Quality Products Reviewed for Roughness / Smoothness and Rideability

 Advisory Circular 150/ “Guidelines and Procedures for Measuring Airfield Pavement Roughness” Provides Guidance to quantify the surface irregularities and their effects on aircraft response Used after Construction Used During Design FAA Software ProFAA Boeing Bump Straight Edge IRI Profilograph Profilograph Bump Template

 Runway Intersecting Pavements can cover areas as large as 3.5 acres (not including the shoulders)  When flattening grades and adjusting pavement profiles DRAINAGE becomes a concern HAVE WE MADE THE SURFACE BETTER???

 Large Pavement Areas with Minimal Slopes ~ The Innovative Pavement Research Foundation (IPRF) and The Airfield Asphalt Pavement Technology Program (AAPTP) indicate that Both Rigid and Flexible Paving Techniques have built in Errors Stringline Thermal Expansion or Sag Mix Specific Variations Flexible – Roll Down Factors Rigid – Edge Slump Characteristics Human Related Tolerances for Set Up of Equipment Equipment Grading Equipment (GPS, Lasers or Surface) Slope Controls Variable Placement Thickness Flexible Pavements Paste Quality Rigid Pavements

 All Errors Meet Specification Requirements for Single Lane Passes  All Errors Compound in Multi-lane Passes Across Large Pavement Areas  Minimal Slopes or Flat Grades in Large Pavement Areas Provide Construction Difficulties Designs should incorporate a minimum of 0.50% slope in either direction for construction of large pavement areas……. PREFERABLY BOTH

Buffalo-Niagara International Airport (BNIA)

 In 2006, the Intersection of Runway 5-23 and Runway is completed using Four (4) Separate Weekend Closures  In 2006, Corrective Milling and Paving was Performed to Correct Grades and Eliminate Ponding using Two (2) Weekend Closures  In 2006, Additional Maintenance to Improve Operational Conditions was Implemented for Surface Drainage  Intersection Provided Acceptable Rideability and Smoothness

 Evaluation Indicated Acceptable Data  Runway 5-23  Boeing Bump Index Average < 0.25  Boeing Bump Index Maximum = 0.5  Runway  Boeing Bump Index Average < 0.4  Boeing Bump Index Maximum = 0.72  Acceptable Value < 1.0

 Runway 5-23  Longitudinal Profile Slope Average = 0.40%  Cross Slopes  South-East Average = 0.20%  North-West Average = 0.15%  Minimal Recorded Slope = 0.05%  Runway  Longitudinal Profile Slope Average = 0.10%  Cross Slopes  Transverse Average = 0.35%  Minimal Slope = 0.29% Paving Using 0.50% Cross Slope ¾ inch in 12½ feet 1½ inch in 25 feet

 Mitigation of Water Ponding  Current Process  Brooming  Proposed Alternatives  Drainage Holes  Altering Surface Grades  Grinding Channel Areas  Use of Porous Friction Course (PFC)  Combination Grinding & PFC  PVC Drainage System

 Intersection Consists of a Deep Pavement Section  Drainage of Surface Water through the Base Course was Considered  Spot 3 Locations where water was to Drain  BNIA Staff to Monitor the Holes

Holes Did Not Drain at a Significant Enough Rate to Pursue This Option

 Modifying Cross Slope to Increase Grading where Water is Ponding Too Much Risk and Cost for Minor Grade Modifications

 Construct Channels by Diamond Grinding  Channels to Drain the Surface from the Low Points to the Edge of Pavement  Design Incorporating Roughness Criteria  Use ProFAA software to analyze smoothness

Depths Exceeded 1 inch with Channel Profiles at 0.25%

 Mill and Replace Channel Areas Using Variable Depth Porous Friction Course (PFC)  Provide Channel – No Change to Surface Grades  Slope Increase at Bottom of PFC to be 0.15%  Provide a Surface Matrix for Water to Drain Within

Minor Drainage Slope with Risk of Contamination with Fines

 Construct Grinding Areas Indicated Above  Perform Variable Depth Mill and Replacement Using PFC  Increased Slope  0.25% for Grinding  0.15% for Variable Depth Mill and Replacement  Total Increase 0.40%  Total Area would need to Increase for Milling and Paving Operation Analysis Indicated Large Areas of Different Material Surfaces May Effect Aircraft Operations – Variable Friction Coefficients Higher Surface Area Maintenance - Contamination - Long Term Drainage - Replacement Estimated at 5 years

 Slot Drains Installed in the Surface  Provide Similar Drainage Below the Surface  Concept  Install Along the Ponding Area  Limit Damage from Snow Plow or Other Maintenance Work  Provide Minimal Disturbance to Pavement  Installation Similar to Electrical Conduit  Remove Surface Water to Existing Storm System.

Preliminary Layout

 Conceptual Design  Preliminary Design - Storm Intensity of ½” of water per hour  Install 4” diameter Sch 40 PVC Conduit (Collection Pipe) at a 1.5+ percent fall with Outlet Pipes at 2.5+ percent fall to Existing Storm System  Install 2” diameter Sch 40 PVC Conduit Risers to Surface of Pavement at a 20 to 40 feet spacing  Install Cleanouts  Encase System in P-610 PCC  Minimal Grind around Riser Pipes to Promote Inflow of Water to the System Determined to be a Viable Option for BNIA Detailed Design and Construction to Be Performed in 2011

 Existing Longitudinal and Transverse Cross Slopes through the runway intersection are less than 0.50%  Pavement through the intersection meets appropriate roughness criteria established by the FAA  Intersection requires removal of water by mechanical means during a rain event  Redesign and Repaving the intersection is considered too costly for drainage repair - 4 years into its service life  Use of the PVC Drainage System is currently considered feasible for the removal of water  Detailed design and construction scheduled for 2011

 Warping grades through Runway Intersections should NOT just accommodate roughness  The use of the FAA ProFAA software to evaluate the Boeing Bump and Maximum Bump Criteria are consider valuable tools  Longitudinal and Transverse Slopes should be evaluated using a basic understanding of the construction industry  Designers should minimize the areas where slopes will be less than 0.50% It is Feasible to have a Designed Grading Plan that Drains Water BUT Can it be Constructed to Drain?

A proper intersection design will meet ACCEPTABLE roughness limits for aircraft use AND provide adequate drainage to meet other operational constraints

 The Paving Industry requires that a minimum of 0.50% should be observed to facilitate surface drainage in large paving areas  Intersection design should observe these limitations  Use of ProFAA is not limited to post construction analysis and can be used to evaluate pavement roughness during design  Qualified personnel should perform constructability reviews to evaluate paving within runway intersections Special Note: Runway Intersection Repairs are considered unique to different locations One Size Does NOT Fit All!!!!!

Christopher S. Decker, P.E. Roy D. McQueen & Associates, Ltd. John Diebold, P.E. Niagara Frontier Transportation Authority Mathew T. Diffin, E.I.T. Roy D. McQueen & Associates, Ltd.