Contents

  • Cover
  • Front matter
  • Preface
  • Scope, purpose and use
  • 1. Terminology, economic analysis, risk management
    • 1.1 Terminology
    • 1.2 Economic analysis
    • 1.3 Understanding risk
  • 2. Regulations, consents and approvals
    • 2.1 National Environmental Standards for Plantation Forestry (NES-PF)
    • 2.2 Heritage New Zealand Pouhere Taonga
    • 2.3 The Health and Safety at Work Act
    • 2.4 NZ Transport Agency approval for access onto state highways
    • 2.5 District council approval for access onto council roads
  • 3. Planning for roads
    • 3.1 Road classes
    • 3.2 Arterial roads
    • 3.3 Secondary roads
    • 3.4 Spur roads
    • 3.5 Establishment tracks
    • 3.6 Spatial information
    • 3.7 Initial field work
    • 3.8 Manual design method: Stepping out a roadline on a topo
    • 3.9 Running a grade line in the field
    • 3.10 Full road design
    • 3.11 Working with road survey data
    • 3.12 Geometric road design
    • 3.13 Curve widening
    • 3.14 Horizontal alignment
    • 3.15 Vertical alignment
    • 3.16 Calculating the safe stopping distance
    • 3.17 Setting out the roadline
  • 4. Planning for landings
    • 4.1 Common landing layouts
    • 4.2 Landing planning considerations
  • 5. Road and landing construction
    • 5.1 Soil and rock properties
    • 5.2 Managing adverse environmental effects
    • 5.3 Marking clearing widths
    • 5.4 Roadline salvage
    • 5.5 Daylighting
    • 5.6 Road formation
    • 5.7 Drainage control during earthwork construction
    • 5.8 Earthwork machinery
    • 5.9 Estimating machinery production
    • 5.10 Stabilising cut and fill slopes during construction
  • 6. Pavement design, subgrade preparation, pavement construction
    • 6.1 Traffic loading
    • 6.2 Evaluating subgrade properties
    • 6.3 Determining pavement depth
    • 6.4 Pavement material properties
    • 6.5 Compaction of subgrade and pavement
    • 6.6 Compaction equipment
    • 6.7 Pavement construction
    • 6.8 Weak subgrades
    • 6.9 Chemical stabilisation of pavement or subgrade
  • 7. Erosion, sediment and slash control structures
    • 7.1 Ditches
    • 7.2 Cut-outs
    • 7.3 Berms
    • 7.4 Drainage culverts
    • 7.5 Flumes
    • 7.6 Sediment traps and soak holes
    • 7.7 Silt fences
    • 7.8 Sediment retention ponds
    • 7.9 Debris traps
  • 8. River crossings
    • 8.1 Fish passage
    • 8.2 Selecting the location and crossing type
    • 8.3 Fords
    • 8.4 Temporary river crossings
    • 8.5 Single culvert river crossings
    • 8.6 Battery culvert river crossings
    • 8.7 Drift deck river crossings
    • 8.8 Single span bridge river crossings
    • 8.9 Prediction of flood flows, and sizing culverts
  • 9. Road maintenance, repairs and upgrades
    • 9.1 Maintenance programme
    • 9.2 Economic evaluation of road maintenance projects
    • 9.3 Managing maintenance requirements
    • 9.4 Commonly used maintenance machinery
    • 9.5 Road surface maintenance
    • 9.6 Road foundation maintenance
    • 9.7 Landing rehabilitation and decommissioning
    • 9.8 Roadside vegetation maintenance
    • 9.9 Erosion and sediment control structure maintenance
    • 9.10 River crossing maintenance
  • Forest road engineering terminology
  • References
  • Websites, resources, databases

NZ Forest Road Engineering Manual

  1.  ›
  2. 9. Road maintenance, repairs and upgrades ›
  3. 9.1 Maintenance programme
 

9.1 Maintenance programme

Research shows that it is far less expensive to keep a road in good condition than it is to repair it once it has deteriorated. Road maintenance is about the life of the road. Roads are maintained to:

  • Prolong their life
  • Save money in the long-term, by rectifying damage before major rehabilitation is required
  • Increase operator health, safety and comfort
  • Minimise environmental impact
  • Guarantee easy access for emergency services and for forest protection. For example, ambulances and firefighting equipment
  • Reduce vehicle operating costs.

Pavement management systems are widely used to keep track of roads and their conditions. They provide an inventory of road condition, a priority rating of the importance of each road, a maintenance schedule to keep certain roads in good condition, and a schedule of repairs of lower rated roads for when funding is available.

Maintenance requirements on each road class are likely to vary, and can be classified into two categories – preventative, and on-demand corrective. The maintenance strategy adopted will be determined by the importance of the road link in the network.

Arterial roads generally require frequent maintenance. They are the major feeder routes into and out of the forest block, so must remain open. Preventative and on-demand maintenance is necessary.

Secondary roads also typically require frequent maintenance. They link spur roads and arterial routes. Most secondary roads have a steady flow of both heavy traffic and light vehicles. Spur roads are usually only repaired during the period they are required for harvesting operations. The level of maintenance required is minimal, depending on the level and frequency of use. During harvesting, wood extraction operations may result in high numbers of heavy vehicle movements on the roadway, whereas during other periods, only light silvicultural traffic movements are likely. Some companies may stop maintaining these roads if they do not provide strategic access, and do not increase safety, environmental or fire risk.

Establishment tracks generally require little, if any, maintenance as there is infrequent and light vehicle use, so vehicle damage is minimal. However, keeping access open should be considered if they provide access for firefighting.

9.1.1 Preventative maintenance

Preventative maintenance is routine maintenance carried out on the road from the time it is constructed. This is to help prevent major defects, and pavement damage from occurring. It is about preventing any road failure, so works occur when any weaknesses first show rather than when it becomes urgent. This prolongs the life of the road but may also have a high cost, since it requires regular inspection and a high ongoing demand on resources. Preventative maintenance has the following characteristics:

  • Typically, a higher total road management cost
  • An increased service life of the road
  • Reduced vehicle operating costs
  • An increase in safety for road users
  • More consistent use or allocation of maintenance resources.

If defects are left too long, they can cause severe damage that may require extensive pavement rehabilitation. Failure to undertake preventative maintenance – such as culvert entrance clearance – may result in significant environmental damage and greatly increased rehabilitation costs.

9.1.2 On-demand corrective maintenance

On-demand corrective maintenance is irregular maintenance needed to correct defects as they are identified. This level of maintenance may incur lower ongoing cost, but may result in the need for major rehabilitation earlier than otherwise necessary.

On-demand maintenance procedures can:

  • Reduce the overall efficiency of maintenance resources, with more urgent repairs becoming necessary
  • Result in higher vehicle operating costs.

The challenge with corrective maintenance is if the maintenance is held off and not scheduled when road degradation starts, then it can rapidly spiral into expensive road repairs.

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