Optimising Gravel Road Maintenance Strategies

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					Optimising Gravel Road Maintenance
             Strategies


             Presenter:
            Gerrie van Zyl
                           Scope

     • Introduction
     • Road management systems
     • Utilising information to improve maintenance
       strategies
     • Blading optimisation process
     • Conclusion




August 3, 2009                                        Slide 2
Integrated Road Management Systems



                                            ROAD REFERENCING SYSTEM



  NETWORK INTEGRATION MODULE                    ROAD PROCLAMATION SYSTEM




                                                  TRAFFIC SURVEILLANCE SYSTEM




                                                PAVEMENT MANAGEMENT SYSTEM



                                              UNSEALED ROAD
                                            MANAGEMENT SYSTEM



                               BRIDGE MANAGEMENT SYSTEM
                          ACTIVITY FLOW IN ROAD MANAGEMENT


                                          Inventory
                                                               Condition
                   Maintenance/                                monitoring
                   rehabilitation
                   or upgrading

                                                                            Condition
   Detailed
                                                                            description
   investigation
   and design
                                            DATA
                                         MANAGEMENT
                                                                            Analyses
                                                                            Deterioration
                                           Location
                                                                            Measure selection
  Project Planning                        referencing


                                                                        Prioritisation &
      Fund allocation                                                   Optimisation

                                                      Presentation to
                        Final                         Management
                        prioritisation
                                                                                           4
GvZ 2008
  Location Referencing and Inventory

• Road No
• Start & End
   – Description
   – Km
   – GPS
• Attributes
   –   Category
   –   Surface type
   –   Geometry
   –   Features
   –   Etc.
                          ACTIVITY FLOW IN ROAD MANAGEMENT


                                          Inventory
                                                               Condition
                   Maintenance/                                survey
                   rehabilitation
                   or upgrading

                                                                           Condition
   Detailed
                                                                           description
   investigation
   and design
                                            DATA
                                         MANAGEMENT
                                                                              Deterioration
                                                                              modelling
                                           Location
  Project Planning                        referencing

                                                                        Prioritisation &
                                                                        Optimisation
      Fund allocation

                                                      Presentation to
                        Final                         Management
                        prioritisation
                                                                                           6
GvZ 2008
                    Condition Assessment

     • Formalised visual assessment (TMH12)
     • Roughness
     • Material thickness and properties
     • Insitu strength (DCP)

     • Additional information
           – Traffic
           – Climate
           – Topography

August 3, 2009                                Slide 7
                 Condition assessment
    • Visual assessment
    • Roughness
    • Layer thickness
    • Material properties
    • DCP
    • Unit costs




August 3, 2009                          Slide 8
DCP testing
         LAYER-STRENGTH DIAGRAM
              km 3.4 TR22/2


  1000   100                                    10                   1
            80        45        25        15         7       3           0

                                               Inadequate strength
                                                                         100



                                                                         200



                                                                         300



                                                                         400



                                                                         500



                                                                         600



                                                                         700



                 80        45        25        15        7       3       800
            Condition description

• Condition description (Network)




                                    10
                                                       Reporting

 • Condition trends
          Very Poor       Poor        Fair      Good         Very Good
100%

80%

60%

40%

20%

 0%
    97

           98

                  99

                         00

                                01

                                       02

                                               03

                                                      04

                                                             05

                                                                    06
  19

         19

                19

                       20

                              20

                                     20

                                             20

                                                    20

                                                           20

                                                                  20




                                                                         11
                 Reporting




August 3, 2009               Slide 12
              Project Control Module

               Project Activity Cost Analysis



                                                   12.8%
                                                  Breaking
                                                Down Material


   34.4%
Transport &
  Tipping
                             Gravel Loss
                                                                   DR1303(30-30.5)


 • Function of:                                     120

                                                    100




                                 Gravel loss (mm)
       –   Material properties                       80

                                                     60


       –   Climate                                   40

                                                     20


       –   Traffic                                    0
                                                          0   1    2             3             4    5          6


           Construction
                                                                  Time after construction (years)
       –                                                               Actual   HDM4      TRH20



       –   Blading frequency
 • Calculate remaining life
       – Minimum thickness




August 3, 2009                                                                                          Slide 14
                                               PERFORMANCE MONITORING
 Visual assessment of distress type
 Roughness measurement
 Gravel loss and shape change
 Structural capacity
 Change in material properties
                                                                     DR1318


                                                                                                           11.400

                                                                                                           11.200

                                                                                                           11.000

                                                                                                          10.800
                                                                                                                    Relative Height
                                                                                                          10.600

                                                                                                          10.400

                                                                                                          10.200
                       t
                   ig h                                                                                   10.000
                 5R
              2.2
                                 ter
                                                                                                 km1.20
                                                                                        km1.22




                             n
Offset (m )                Ce
                                                                              km1.24
                                                                     km1.26




                                              ft
                                                            km1.28




                                           Le
                                                   km1.30




                                       5
                                   2.2                                                 Stake Value
                           Material information availability
                                       TRH 20 Classification
                         500
                                                                   D
     Shrinkage product



                                                                Slippery
                         400

                                                           Good (Dusty)
                         300
                                      A                                                C
                                   Erodible                       E                   Ravel
                         200

                         100
                                       Ravel & Corrugate                         B
                          0
                               0   4      8   12    16     20     24   28   32   36   40   44   48

                                                    Grading Coefficient

Shrinkage product (Sp)                             = % linear shrinkage x % passing 0,425 mm sieve

Grading coefficient (Gc)
= ([% passing 26,5 mm – % passing 2,0 mm]x % passing 4,75 mm) / 100
Materials Information System
            Roughness deterioration
• Impact of different
  strategies




                                      18
                       Light blading

• Remove cohesionless material




• Spread fine material (moist &
  slightly plastic)
                         OBSERVATIONS AND IMPLICATIONS

• No deterioration after blading at low roughness
  levels
                                     T R 5 8 /1 : k m 4 6 .9 - 4 7 .4 : R o u g h n e s s D e te r io r a tio n (M o d e l vs . A c t u a l)


                           6
                                 Model prediction
                         5 .5    versus measured
                           5
  Riding Quality (IRI)




                         4 .5


                           4

                         3 .5


                           3

                         2 .5


                           2
                            0 .0 0                                                                                                   0 .5 0
                                                                          Y e a r s s in c e c o n s t r u c t io n


                                                                        A c tual Q I              TR H 2 0 : B la d in g
                    Effect of regular light blading

                         ROUGHNESS PROGRESSION
                              MR 584 km 2.7


          250

          200

          150
     QI




          100

          50

           0
                0   1           2                3          4        5
                                     Years

                    Normal Maintenance       Actual Roughness



                                                                           AADT = 86, 14% heavy




                                                                Slide 21
August 3, 2009
                                    CONCLUSIONS ON RESHAPING
• Reshaping more economic than continuous
  blading at high roughness levels
                                          MR276: km1.8 - 2.3: Roughness Deterioration (Model vs. Actual)


                                  Actual QI          HDM Adjusted Constr f=0.8           HDM Blading (normal compaction)

                        250
                                                                                                                               AADT = 323, 19% heavy
                                                                                                      Effect of reshaping             (2001)
                        200
                                                                                                      (Adjusted model)
 R iding Quality (QI)




                        150



                        100



                         50



                          0
                              0       1          2            3          4           5            6          7             8
                                                              Years Since Construction
                                                                                                                                    AADT > 500
                                                                                                                                      (2007)
                 SIMPLIFIED DECISION TREE FOR REMEDIAL MEASURES


                                                      MATERIAL       EXPOSED   SUBGRADE
    ACCESSIBILITY   SAFETY     GRADEABILITY                                               SURF DRAINAGE
                                                                    SUBGRADE   STRENGTH
                                                      THICKNESS
                                                                                                             1st Level MEASURE
                                                                                                                1-CONSTRUCT
         POOR
                             GEOMETRY                                                                           1-CONSTRUCT
                                                                                                     LEVEL      2-FORM & GRAVEL
                                                                                            POOR
                    POOR     OTHER
                                                                                                     OTHER      3-GRAVEL
                                                                                             OK                 3-GRAVEL
                                             ROCK or SAND POOR       YES                                        3-GRAVEL
                                                                   ISOLATED                                     4-SPOT GRAVEL
                                     POOR                            NO                                         4-SPOT GRAVEL
                                                          OK        YES                                         6-SPOT GRAVEL
          OK                                                       ISOLATED                                     4-SPOT GRAVEL/GRAVEL
                                                                     NO                                         4-SPOT GRAVEL/GRAVEL
                                              OTHER      POOR                      POOR                         3-GRAVEL
                                                                                   OK                           7-REWORK /GRAVEL
                                                          OK       YES             POOR                         6-SPOT GRAVEL
                                                                                   OK                           7-REWORK /GRAVEL
                     OK                                           ISOLATED
                                                                                                                5-REWORK/ SPOT GRAVEL
                                                                   NO                                           8-REWORK
                                        OK                POOR     YES            POOR                          3-GRAVEL
                                                                                  OK                            11-SPOT GRAVEL/B LADING
                                                                   ISOLATED       POOR                          6-SPOT GRAVEL
                                                                                  OK                            11-SPOT GRAVEL/BLADING
                                                                    NO                             LEVEL        9-FORMING
                                                                                          POOR
                                                                                                   OTHER        10-RESHAPE
                                                                                           OK                   11-SPOT GRAVEL/BLADING
                                                          OK
                                                                         YES     POOR                           6-SPOT GRAVEL
                                                                                                   LEVEL        9-FORMING
                                                                                 OK       POOR
                                                                                                   OTHER        10-RESHAPE
                                                                                           OK                   12-NOR BLADING
                                                                    ISOLATED      POOR                          6-SPOT GRAVEL
                                                                                                    LEVEL       9-FORMING
                                                                                  OK       POOR
                                                                                                    OTHER       10-RESHAPE
                                                                                            OK                  12-NOR BLADING
                                                                         NO                         LEVEL       9-FORMING
                                                                                           POOR
                                                                                                    OTHER       10-RESHAPE
August 3, 2009                                                                              OK                  12-NOR BLADING Slide 23
August 3, 2009   Slide 24
                  Measure Selection

   • Routine maintenance
   • Scheduled maintenance
   • Upgrading to surfaced/ seal




August 3, 2009                        Slide 25
                 Routine maintenance

     • Light and heavy blading
     • Maintain drainage systems
     • Vegetation control
     • Fence repair
     • Signage maintenance
     • Patching




August 3, 2009                         Slide 26
                 Periodic/ Scheduled Maintenance


     • Forming ?
     • Gravelling or spot gravelling
                                           Network level
     • Reshaping
     • Reworking

     • Panel Inspections
                                           Project level
     • Site verification
     • Final prioritisation
     • Fund availability - Work program
August 3, 2009                                             Slide 27
             Blading optimisation

• Part of operational (day-to-day) Maintenance
  Management System
Balance between theory and practice
                ?
          Factors influencing blading program

     • Funding
     • Organisational policy (uitslaap), depots
     • Effectiveness (Grader availability, working hours)
     • Road condition, material and maintainability
     • User requirements
     • Methodology and operator abilities
     • Emergencies


                              Slide 30
August 3, 2009
Define network

Define Uniform Maintenance sections


Define Minimum & Appropriate LOS
                                                          Feedback
Determine minimum & appropriate
blading frequency and adjust
                                                      Min Fund
                                                      Required
Determine Min & Appr. Blading type, Blade   Unit
passes, Blade km/ maint sect per annum      Costs                     Fund
                                                      Appropriate     allocation
                                                      Funding
Determine/ Allocate Grader                            Requirement
Productivity per road/ area
                                              Grader requirements
Combine maint sections to obtain balanced
                                              Strategies
Distribution per Ward/ Maint Area


Distribute blading requirements             Recalculate affordable blading
to balance cycles: Blading Schedules        frequency per maintenance section


Verify monthly program on site & issue
       Results after implementation
• Well defined monthly programs
• Major reduction in complaints
• Positive feedback from communities/ RU
• Ability to adjust blading programs with reduced/
  increased funding
• Ability to manage emergency work
                      CONCLUSIONS
• Formalised systems essential
• Integration of systems
  –   Location referencing/ inventory
  –   Traffic
  –   Unsealed road management system
  –   Maintenance Management System
  –   Project Control System (Costs)
  –   Materials Information System
  –   Experimental data
• Strategic & tactical (Network)
• Operational level (Project)
• Blading optimisation (Process)
                 The way forward ?




August 3, 2009                       Slide 36
Any questions?