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Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
OPTIMIZED PAVEMENT DESIGNWITH RESPECT TO
QUALITY AND ECONOMY
Institute for Road Construction and MaintenanceVienna University of Technology
J. Litzka
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
General objective of pavement design
2
Structural efficiency during the whole design period
Based on given random conditions
- Design traffic load
- Bearing capacity of subgrade
- Material properties of pavement layers
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
For routine application (1)
3
Average or minimum values of- Subgrade
- Material properties and fatigue behaviour
Pavement design according to given design traffic (load class)
e.g. catalogue type(like Austrian RVS 3.63, based on analytical calculations)
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
For routine application (2)
4
Resulting in a number of technically equivalent pavement solutions
Based on availability of materials and/or on cost comparison the optimal
solution can be selected together with possible alternatives
But still a general solution based on plausible assumptions, not always most cost effective
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY 5
Design table RVS 3.63, bituminous pavements
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Possible improvement of economic efficiency (1)
6
Specific analytical design using the underlying procedure for the catalogue, but
Real given values of bearing capacity of subgrade, material characteristics of layers, specific fatigue laws
Also possibility to include new, innovative, not standardised materials
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Possible improvement of economic efficiency (2)
7
Example
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Essential precondition
8
Exact and reliable information about input characteristics
Performance orientated laboratory tests (stiffness modulus, fatigue behaviour etc.)
(t)
(t)
Traffic forecast of high accuracy
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Benefits of specific pavement design
9
Better adaptation to existing subgrade situation
Better utilisation of material properties
Possibility for innovative materials and solutions- Alternative bids
- Performance related contracts
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Further advantage of specific analytical design
10
Stage by stage construction
- Stage 1 as basic solution for first part of design period
- Stage 2 designed based on existing layer properties and realistic design traffic
Better reliability and also acting as maintenance procedure
but: Do not overlook the right moment
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Consideration of costs
11
Construction costs
Life-cycle costs
- Construction
- Maintenance
- Additional user costs (e.g. time loss)
- Environmental costs (possibly)
• Routine• Rehabilitation including
- Traffic management at construction sites- Methods/measures- Intervals
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Calculation of life-cycle costs
12
Prognosis of development of pavement condition necessary
Prediction of life time, change of condition indicator-values and thus prediction of time and type of maintenance measure
Basic tasks for PMS/e.g. VIAPMS
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Change of approach and responsibilities
13
Only construction costs considered
Client chooses contractor according tocost comparison
Sometimes alternatives compared
Actual:
Consider life-cycle costs
At least for road owner costs(construction and maintenance)
New approach (even if normal tender):
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
For functional contracts (PPP)
14
Responsibility of concessionaire/contractor to consider
- Complete life-cycle costs
- Including additional user costs(e.g. loss of toll/fee during
rehabilitation works, closures)
Normally compliance with trigger values of pavement condition required
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Functional contracts - example
15
1,5
1,0
2,0
2,5
3,0
3,5
4,0
4,5
5,05
10
15
20
35
technical parameter [mm]
con
dit
ion
in
dex C
I [-
]
0
I
II
III
IV
V
conditionclass
very good
good
fair
poor
very poorThreshold level
Warning level
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Most crucial point: Performance models
16
Standard- type pavements, traditional materials
- Empiric results from database analysis
But still more risks compared with routine application within maintenance
planning- Starting from new pavement
- No calibration of performance models to actual measurements possible
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Most crucial point: Performance models (2)
17
Innovative, new materials and pavements- Prognosis based on analytical calculation
With this also required minimum quality of road condition secured
- First assumption based on existing empiric functions and adaptation by periodic condition measurements (normally required in any case)
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Optimized solution
18
Construction costs
Maintenance costs
including additional user costs
Minimum life-cycle costs
- Most economic solution
- In compliance with given quality requirements
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Development Pavement Condition – Concrete Pavement
19
Concrete Pavement
Bit. Base Course
Subbase
Threshold Level
Warning Level
Exchange of distressed slabs and thin bit. overlay
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Development Pavement Condition – Asphalt Pavement
20
Wearing Course
Bit. Base Course
Subbase
Threshold Level
Warning Level
ReinforcementBase Course
Overlay
Total thickness according to design
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Development Pavement Condition – Asphalt Pavement
21
Wearing CourseBit. Base Course
Subbase
Threshold Level
Warning Level
Reinforcement (2nd construction stage)
Base Course
Overlay
2-stage pavement construction
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Comparison Total Costs (including user costs)
22
Reinforcement(2nd construction stage)
OverlayReinforcement
Replacement of distressed slabs and thin
overlay
Overlay
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Conclusions (1)
23
Increased traffic loads
Limited budgets
Saving of resources
Minimised impact to road users(important for toll roads)
Optimized pavement design necessary with respect to
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Conclusions (2)
24
Improved design methods
Improved materials
Long life, modular pavements
Improved construction quality(very important)
Optimized pavement design possible by applying
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Conclusions (3)
25
Normal contract
Optimized pavement design necessary and possible if
- Administration responsible for design and maintenance
Functional contracts (PPP)
- Concessionaire responsible for design, construction and maintenance over the full concession period together with guaranteed remaining lifetime after termination of contract
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY
Conclusions (4)
26
Improved, innovative materials
Improved, performance related laboratory tests
High quality of construction
Optimal maintenance organisation
For optimized pavement design necessary in any case
and
Enough time for development of alternative solutions and attributed laboratory tests and calculations during the bidding process
Institute for Road Construction and Maintenance - Vienna University of Technology
ISTU
J. LITZKA - OPTIMIZED PAVEMENT DESIGN WITH RESPECT TO QUALITY AND ECONOMY 27
Thank you for your attention