improving pavement performance part 1

Slide 1Improving Pavement Performance
New Pavement design Procedure
Also know as…
History of pavement performance in South-Africa
Isolated from international community: late 1970’s to mid 1990’s
Oil ??
Force innovation
History – Damage models
Fatigue of asphalt wearing courses (Freeme – 1970s)
Fatigue of asphalt base layers including temperature (Published data – 1970s to 1980s)
Permanent deformation for unbound material (Maree – 1970s to 1980s)
Effective fatigue and crushing failure for cement stabilized layers (de Beer – 1980s)
Vertical strain criteria for subgrade (Dorman and Metcalf – 1965)
1970’s – 1980’s
Problems with current method
Users became disillusioned with the method
Counter-intuitive and inadmissible results
Inconsistent input
Strength parameters
Outdated models
AAPA 2011 Study Tour – Improving Pavement Performance #1
R&D Dream #1: Close Gap Between Reality and Theory
Adjust the Theory to Predict Reality
Theory
Reality
Rut
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R&D Dream #3: Single “Tool” – Different User/Risk Levels
Young professional
Seasoned professional
Special investigations
Specialist designer
Unusual materials
Process
November 2005: P&R framework established
November 2006: Project briefs ready
February 2008 – PPIS
revisit LTPP sections
Concept
It will include:
Traffic loading predictions
Material resilient response
Pavement resilient response
AAPA 2011 Study Tour – Surface Treatments #1
www.aapa.asn.au
Good
Fair
Poor
Two Roads, same condition & traffic – but only budget for one ?
A
B
Asset Management “101”
We typically structurally design roads for the traffic loading expected over 20 to 30 year period, so a road is not necessarily designed for 20 calendar years, but the traffic expected in 20 calendar years.
Let say we have two roads today, call them A & B, as seen they are both in the exact same condition, and have the exact same traffic, but only have funding for one of them, what do you do ?
Well if I told you that I had historic condition data, and from this data the following trends can be observed, then one can with more certainness go for option B, why, because the consequences of maintenance delay is the highest, or in other words it deteriorates the fastest.
If we now add the further ability to predict future anticipated performance, the decision is even easier.
What Is The Price We Pay (SANRAL)
Repair Cost = X / km
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This slides indicates the primary reason for why SANRAL is in the process of incorporating roads that is part of the strategic national road network currently under Provincial government control, under its jurisdiction. Due to no or very little preventative maintenance being performed by provincial governments as a result of severe budget and capacity constraints, the strategic road network has entered a phase of accelerated deterioration. As seen the cost impact of delaying maintenance on a road maintenance delayed by 3 years will result in an additional cost of six (6) times the original amount. And should commencement of maintenance be delayed a further 2 years the funding requirement will increase dramatically – eighteen (18) times the original amount.
Very Poor Condition
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As seen from this slide the impact of a deteriorating road network is primarily on the road user, with road user costs increasing more than 100 % from good to very poor road. Although this cost increase is not directly felt by government, the economy is severely impacted.
Asset management = planning
Asset Management System
Policy/Procedures – Principles/Rules to Guide Decisions and achieve rational outcomes – what, where, when, how.
Funding – Financial resources for operation and results implementation.
People - People make decisions, the rest are just to support the process.
Hardware – Road Survey Equipment + IT Infrastructure.
Software – Computer based data Analysis and Storage Tools.
Data – Knowing what you have, its condition and performance Trend.
Hardware
Software
Data
People
Funding
Policy/
Procedures
Standardization of measurement conditions (speed, reference temperature, principle)
Innovation: Real time car sensor monitoring
For asset management to be successful all the “pieces of the puzzle” need to be in place in a “balanced equilibrium”
It does not help you have the most advance survey vehicle but no means to effectively store and analyse the data, or
Have the most sophisticate software, but the quality of your data is suspect !
Without Funding and People – Nothing will happen !!!
Hardware
Software
Data
People
Funding
Policy/
Procedures
Standardization of measurement conditions (speed, reference temperature, principle)
Innovation: Real time car sensor monitoring
Collect data
Road condition
Traffic
Road User Effects
Condition Surveys
Economic Analysis
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Using dynamic segmentation the network data is broken up into uniform sections, which is then analysed using our PMS Decision Support Software. The process consists of modeling the Road deterioration, followed by the effects of maintenance, then calculating the effects on user costs for the various treatments. Finally the economic analysis is performed followed by budget optimisation to produced the recommended works programme.
Performance prediction
HDM4
PERS
dTIMS
Good
Fair
Poor
Effect of intervention on pavement performance
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Asset Management “101”
We typically structurally design roads for the traffic loading expected over 20 to 30 year period, so a road is not necessarily designed for 20 calendar years, but the traffic expected in 20 calendar years.
Let say we have two roads today, call them A & B, as seen they are both in the exact same condition, and have the exact same traffic, but only have funding for one of them, what do you do ?
Well if I told you that I had historic condition data, and from this data the following trends can be observed, then one can with more certainness go for option B, why, because the consequences of maintenance delay is the highest, or in other words it deteriorates the fastest.
If we now add the further ability to predict future anticipated performance, the decision is even easier.
Chart1
SANRAL AMS Budgeting Procedure
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To ensure accurate decision making, accurate data is required. The data collected on SA National Roads include, visual assessment, I.e. cracking, potholes, patching, ravelling etc, roughness in IRI, HRI, rut depth, texture depth in MPD, surface friction using SCRIM and structural strength using FWD. The calibration/validation procedures and detail and frequency of data collection is all contained within our paper. Two other important data items collected is also traffic data, including WIM, and bridge condition data. All data is collected using GPS, we use Omnistar network enabling realtime differential data accuracy of less than 2m at speeds of 100 km/h.
AMS - Information Sharing
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This ability to manage data is becoming more important the further we move in the pyramid from the data creator to the data viewer. It is for that reason when supporting the data viewer the IT infrastructure is of significant importance. In most organisations, a relatively small number of people actually creates data. But for every data creator, there are perhaps ten data users. They need easy access to current, correct data. And there’s perhaps another ten-fold increase in the number of people inside and outside the organisation who simply need to view the data (not manipulate the data).
In order to make the reuse of technical data it is important that the information flow all the way up to the viewer.
As a user can be a viewer, as well as a doer the next moment, we believe that it is of great importance that all of this can happen through a common user interface in a transparent way.
This ability to manage data is becoming extremely important.
AAPA 2011 Study Tour – Surface Treatments #1
Before 1994
1994 onwards
National roads
Nationally allocated
New bill
Nationally via SANRAL
BUT: Provincial authorities to have asset management system in place + data < 2 years old
Capital projects still from provincial fiscus
Metros and municipalities to follow
Main reason Roads national asset
Future or Road maintenance funding in South Africa
End of part 1
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improving pavement performance part 1

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