Browsing by Author "Piyasena, YPSR"

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    item: Thesis-Abstract
    Finding AADT thresholds for upgrading low volume roads in Sri Lanka (using HDM-4 model)
    (2016-03-05) Piyasena, YPSR; Mampearachchi, WK
    The Highway Development and Management Tool (HDM-4) is a powerful system for the analysis of road management and investment alternatives and it is used to prepare road investment programmes and to analyse road network strategies. In this study, the HDM-4 tool is used to find the AADT thresholds based on traffic, subgrade and climate for upgrading low volume roads to maximize economic benefits in Sri Lanka. Several road sections were defined based on different possible traffic, subgrade and climatic conditions for Gravel, Penetration Macadam (PM), Surface Dressed (SD), Portland Cement Concrete (PCC) and Asphaltic Concrete (AC) pavement types. Altogether more than 120 sections were modelled in HDM-4. Level-1 calibration was done in HDM-4 to harmonize with the Sri Lankan condition. Using HDM-4 strategy analysis, different rehabilitation and improvement alternatives were analysed. Maintaining existing pavement considered as the base case. Analysis was done for a 20-year period and optimized for maximum NPV. The outcomes of the analysis EIRR was compared in tabular and graphical forms in order to identify the AADT thresholds for traffic, subgrade and climate for upgrading each pavement type. This shows that traffic volume and growth rate are significantly affected and whereas the effect of climate and of subgrade condition are negligible. Upgrading threshold of low volume road can be decided based on traffic volume in AADT with a fair assessment of the number of heavy vehicles, traffic growth rate and climate condition. According to the study, AADT ranges were defined to get maximum economic benefit for different pavement types of low volume roads in Sri Lanka. Furthermore it can be concluded that low volume roads (AADT less than 1000) in Sri Lanka can use Gravel, PM or SD pavement type with proper maintenance and it is more economical than upgrading to AC or PCC. Keywords: HDM-4, Low volume roads, Pavement upgrading, Road maintenance
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    item: Conference-Abstract
    Finding AADT thresholds for upgrading low volume roads in Sri Lanka (using HDM-4 model)
    (Department of Civil Engineering, University of Moratuwa., 2013-07) Piyasena, YPSR; Mampearachchi, WK; Pasindu, HR
    The Highway Development and Management Tool (HDM-4) is a powerful system for the analysis of road management and investment alternatives and it is used to prepare road investment programmes and to analyze road network strategies. In this study, the HDM-4 tool is used to find the AADT thresholds based on traffic, subgrade and climate for upgrading low volume roads to maximize economic benefits in Sri Lanka. Several road sections were defined based on different possible traffic, subgrade and climatic conditions for Gravel, Penetration Macadam (PM), Surface Dressed (SD), Portland Cement Concrete (PCC) and Asphaltic Concrete (AC) pavement types. Altogether more than 120 sections were modeled in HDM-4. Level-1 calibration was done in HDM-4 to harmonize with the Sri Lankan condition. Using HDM-4 strategy analysis, different rehabilitation and improvement alternatives were analyzed. Maintaining existing pavement considered as the base case. Analysis was done for a 20-year period and optimized for maximum NPV. The outcomes of the analysis EIRR was compared in tabular and graphical forms in order to identify the AADT thresholds for traffic, subgrade and climate for upgrading each pavement type. This shows that traffic volume and growth rate are significantly affected and whereas the effect of climate and of sub grade condition are negligible. Upgrading threshold of low volume road can be decided based on traffic volume in AADT with a fair assessment of the number of heavy vehicles, traffic growth rate and climate condition. According to the study, AADT ranges were defined to get maximum economic benefit for different pavement types of low volume roads in Sri Lanka. Furthermore it can be concluded that low volume roads (AADT less than 1000) in Sri Lanka can use Gravel, PM or SD pavement type with proper maintenance and it is more economical than upgrading to AC or PCC.
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    item: Conference-Abstract
    Finding thresholds based on traffic, sub-grade and climate for upgrading surface type of roads using HDM-4 model
    (Department of Civil Engineering, University of Moratuwa., 2011-07) Piyasena, YPSR; Mampearachchi, WK; Pasindu, HR
    Highway Development and Management Tool (HDM-4) is a powerful system for the analysis of road management and investment alternatives and it used to prepare road investment programmes and to analyze road network strategies. In this study HDM-4 tool is used to find the thresholds based on traffic, subgrade and climate for upgrading minor roads in Sri Lanka. Several road sections were defined based on different possible traffic, subgrade and Climatic conditions for Gravel, Penetration Macadam (PM), Surface Dressed (SD), Portland Cement Concrete (PCC) and Asphaltic Concrete (AC) pavement types. All together more than 300 sections were modeled in the HDM-4. Level-1 calibration was done in HDM-4 to harmonize with Sri Lankan condition. Using HDM-4 strategy analysis different rehabilitation and improvement alternatives were analyzed maintaining existing pavement as considering base case. Analysis were done for 20 years period and optimized to get maximum NPV. The outcomes of the analysis, that is NPV and EIRR were compared in tabular and graphical forms in order to identify the thresholds of traffic, subgrade and climate for each pavement category for upgrading the surface type. This saws traffic volume is significantly affected and effect of subgrade condition and climate is less. It saws upgrading of Gravel road to PM is not feasible unless average daily traffic is greater than 150 vpd and it is not worthy to upgrade to PCC under considered conditions. Upgrade of PM road to SD is feasible if traffic is greater than 600 vpd and not worthy to upgrade to AC or PCC under the considered conditions. Upgrading of SD road to AC or PCC is not feasible under considered traffic and other conditioned. Furthermore it can conclude minor roads in Sri Lanka can used Gravel, PM or SD pavement type with proper maintenance under traffic volumes less than 1500 vpd and it is more economical than upgrading to AC or PCC. But AC or PCC roads can last long in good condition even without any maintenance.