a protocol for the establishment and operations of ltpp sections prepared for gautrans by csir,...
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A Protocol for the establishment and operations of LTPP sections
Prepared for Gautransby CSIR, Transportek
Background
LTPP programmes developed to support the analysis of pavement performance leading to improved engineering tools for design, construction and management
Current LTPP programmes focus on performance models for PMSs
Needs to be a link to APT for greater confidence in interpreting APT results
Background cont..
In SA financial constraints have prevented LTPP test sections being linked to pavement performance under APT
LTPP sections have been developed on an ad hoc basis or as part of calibration sections
Renewed interest worldwide in linking APT to LTPP
Background cont..
For reliable models and design specs, it is imperative that data collected during LTPP programmes are reliabe and consistent with data collected during APT
Protocol already exists for establishment and operations of HVS test sections
Protocol required for LTPP to provide a consistent approach
Structure of Protocol
Linking LTPP to HVS data collection Management and responsibilities Site location and establishment
Data collection Reporting criteria
Minimum measurement requirements
Property LTPP HVS Difference
Visuals Mod TMH 9/HDM calib guide
Description of cracks
TMH-9 standard with added info on cracks
Trans profile Straight edge & wedge/electronic straight edge
Laser profilometer Full lane too wide for laser prof
Long profile Calibrated profiometer
Straight edge LTPP section too long for straight edge
Deflection RSD, FWD RSD FWD used routinely in Gautrans
Perm def MDD MDD
DensityDual probe strata gauge
Dual probe strata gaugeM/C Grav m/c used for
calibration
Pvmnt Temp Temp buttons Temp buttons
Traffic W-i-M HVS
Weather details Weather station Weather station
LTTP Staff Organisation Chart
Project Director
Project Manager
Database manager
Technician’s Assistant (s)
Field Technician
Road Authority/Agency
In-house or service provider
Proposed layout of LTPP sections
A 1 2 3 4 5 B 6 7 8 9 10 C
<20m> 5 x 15m 10m
5 x 15m <20m>
Not to scale
200 m – full lane width
•HDM calibration sections 500 m long covering entire road width
•Detail provided on instrumentation, markings and measurement points
Data collection
Monitoring every 6 months in May and October or when failure occurs
Sampling only from panels A, B and C or if failure occurs in other panels
Recommendations on reinstatement of test pits given to ensure impermeability
Monitoring standards given for: Visual assessment Transverse profile Longitudinal profile Density and M/C DCP Environment Deflection Permanent Deformation Traffic
Laboratory testing
Essential that material properties at the time of construction (or initiation of section) are fully recorded for comparison over time
As built records may not give sufficient detail Testing programme initiated at the following
intervals: Pre-construction/rehabilitation Post construction/rehabilitation In service (approx half-way through the design life of
section) Rehabilitation/end of service
Details of all recommended tests given in the document
Reporting of results
All field monitoring and test data checked by field technician and then PM before sending to the Database Manager
Any lab results sent with field data 1st level analysis carried out after each monitoring 2nd level analysis every 2 years to include:
An evaluation of the structural behaviour The identification of any extraneous effects The development and refinement of performance prediction
models On HVS/LTPP sections, the relationship between LTPP and
HVS performance for similar traffic levels
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