Pavement Management. City of Grande Prairie. Stantec Consulting Limited Thursday, Feb. 28, 2013 Fadi Jadoun, Ph.D., P.E.

Transcription

1 Pavement Management City of Grande Prairie Stantec Consulting Limited Thursday, Feb. 28, 2013 Fadi Jadoun, Ph.D., P.E.

2 Presentation Outline What is Pavement Management & Why Needed? Capital and Life Cycle Cost Grande Prairie Road Network Inventory Why do Pavement Structures Fail? Effect of Structure/Traffic/Subgrade on Performance Pavement Management Overview? History of Grande Prairie s PMS History of Performance Models in RoadMatrix More on PMS Questions

3 What is Pavement Management & Why Needed? Pavement Management System (PMS) is a process to plan the maintenance and rehabilitation of a road network, to optimize pavement conditions over the entire network. Research has shown that it is far less expensive to keep a road in good condition than it is to repair it once it has deteriorated. PMS places the priority on cost-effective solutions that provide the most benefit to the overall network.

4 What is Pavement Management & Why Needed? Preventive Maintenance (PM) is an example of a costeffective solution as it keeps good roads in good condition (relatively inexpensive), rather than reconstructing roads in poor condition (very expensive)

5 Capital and Life Cycle Cost (LCC) Design Life Positive Cash Flow (Savings) Negative Cash Flow (cost) over the life of the pavement Construction Cost Tires Fuel Vehicle Maintenance Safety Road Maintenance & Rehab. = Properly-designed Pavements = Under-designed Pavements = Potential Savings

6 Grande Prairie Road Network Inventory Functional Class Centreline-km Lane-km Arterial Collector Local City Network

7 Why do Pavement Structures Fail? Before we answer the question, note that: Pavements are designed to fail!! Pavement Structures are currently designed using empirically-based procedures, e.g. AASHTO Fatigue Cracking

8 Why do Pavement Structures Fail?, Cont. Assuming a proper construction and geometric design, pavements usually fail due to one or a combination of the following: Inaccurate traffic volume and growth forecast Improper structural design for a certain projected traffic Illegal (heavy) truck loads Material ages, e.g. asphalt oxidizes and stiffens with time; more prone to cracks Weak or non-existent maintenance program due to limited funding. If cracks develop, they MUST be sealed ASAP to prevent water from entering the pavement structure.

9 Effect of Structure /Traffic/Subgrade on Performance Asphalt Concrete Granular Base Asphalt Concrete Granular Base Subgrade Subgrade Thick Structure Thin Structure

10 Pavement Management Overview Pavement Management Concept Defined by GIS sections Network Definition Roughness/Distress/ Deflection Surveys Data Collection Assess Present Status Pavement Management Analysis Needs Analysis Economic Analysis Optimized Rehab Program Implement Program System Maintenance

11 History of Grande Prairie s PMS Stantec partnered with the Province of Alberta to develop the Municipal Pavement Management System (MPMS) for Alberta municipalities in the 1980 s Updated to the MPMA in the late 1990s RoadMatrix succeeded MPMA in the 2000s Grande Prairie was the first municipality in Alberta to migrate to RoadMatrix 1980s 1990s 2000s MPMS MPMA RoadMatrix

12 RT (Stantec s Road Tester) 1. Rutting 2. Alligator Cracking 3. Longitudinal Cracking 4. Edge Cracking 5. Transverse Cracking 6. Map Cracking 7. # of Pot Holes 1. RCI (Riding Comfort Index) 2. VCI (Visual Condition Index) PQI (Pavement Quality Index) = Function of (RCI, VCI, SAI)

13 FWD (Falling Weight Deflectometer) A non-destructive test device. Good repeatability, accurate and fast. Wide loading range (7-120 kn) or (1,500-7,000 lbf) AT* Base Weights for Single Axle = 9,100 kg (89.2 kn) Max. Additional Permitted Weight on Single = 8t (78.5 kn) *Alberta Regulation 315/2002 Use Deflection Data to Calculate: 1. Structural Adequacy Index (SAI) 2. Resilient Modulus, M R

14 History of Performance Models in RoadMatrix Pavement prediction models were specifically developed and implemented for Alberta municipalities A sigmoidal (i.e. S-shaped) form is used in the MPMA for modeling pavement performance due to its flexibility in describing the deterioration of a section. The flexibility of the sigmoidal allows the models produced to be concave, convex, S-shaped, or almost linear. Pavement Performance Curves Northern SAI BGB Thick\Low\Strong Thin\High\Weak

15 Deterioration Curves Structure Traffic Subgrade Strength Thin Low Weak Medium Medium Strong Thick High

16 Deterioration Curves, Cont. Best Case

17 Deterioration Curves, Cont. Worst Case

18 SAI Values for Grande Prairie Functional Class Avg. SAI (2012) Arterial 54 Collector 37 Local 30 City Network 37 Example Sections Section # Description Functional Class West pointe Dr. 74 Ave to 75 Ave West Pointe Dr. 75 Ave to 75 A Ave Pinnacle Blvd. 74 Ave to Pinnacle way Avg. SAI (2011) Avg. SAI (2012) Local Local Local 43 33

19 More on PMS A PMS provides Present Status for each section in the network (PQI) A PMS utilizes Performance Prediction Models to predict performance over time A PMS offers the ability to customize decision trees, which mimic the City s M&R decision-making process Therefore, PMS provides budget and performance based analysis tools to optimize spending

20 Benefits of PMS Realize magnitude of pavement investment Better chance of correct decisions Justify maintenance and rehabilitation programs Objective answers to effects of lower funds on condition, implications of deferred work and/or lower standards Comparative view of network condition (current & future) Improved communications between design, construction, maintenance and planning Preserve knowledge and ensure succession

21 Condition Index Typical M&R Strategies - Definitions Preventive Maintenance: delays deterioration and improves functional condition Light Rehabilitation: non-structural enhancements to extend service life Heavy Rehabilitation: structural enhancements to extend service life and load carrying capacity Reconstruction: replacement of the entire structure Preventive Maintenance (80-100) Light Rehabilitation (50-85) Heavy Rehabilitation (20 60) Full Reconstruction (0 40) Pavement Age

22 Performance Index Three Routes to Pavement Maintenance, 1/ PM Trigger 65 Light Rehab. Trigger 40 Heavy Rehab. Trigger 20 Route 1: Do Nothing End of Pavement Life Full Reconstruction Pavement Age Not-To-Scale

23 Performance Index Three Routes to Pavement Maintenance, 2/3 100 Partial Reconstruction 85 PM Trigger 65 Light Rehab. Trigger 40 Heavy Rehab. Trigger 20 End of Pavement Life Full Reconstruction Route 2: Do Nothing Until a Heavy Rehab. is triggered Pavement Age Not-To-Scale

24 Performance Index Three Routes to Pavement Maintenance, 3/3 100 Crack Seal Crack Seal Overlay Partial Reconstruction 85 PM Trigger 65 Light Rehab. Trigger 40 Heavy Rehab. Trigger 20 End of Pavement Life Full Reconstruction Route 3: Apply Preventative Maintenance (PM) while the Pavement is still good Pavement Age Not-To-Scale

25 Performance Index Properly Versus Under-Designed Pavements 100 Under-Designed Pavement Properly Designed Pavement 85 PM Trigger 65 Light Rehab. Trigger 40 Heavy Rehab. Trigger 20 End of Pavement Life Full Reconstruction Service Life Under-designed Pavement Needs Maintenance Earlier Pavement Age Not-To-Scale

26 Thank You Questions? Fadi Jadoun, Ph.D., P.E. Direct: Cell: