TRF - 2011

Permanent URI for this collectionhttp://192.248.9.226/handle/123/17948

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item: Conference-Abstract
An approach to evaluate horizontal alignment of highways using curvature index and operating vehicle speed
(Department of Civil Engineering, University of Moratuwa., 2011-07) Rajapaksha, RPGKS; Bandara, JMSJ; Pasindu, HR
In recent years, Sri Lanka has experienced an urban traffic congestion that caused a waste of time and energy. It is known that road geometries partly contribute towards decrease in operating vehicle speed. According to conventional Highway Geometric design procedure there is no accurate method to predict operating vehicle speed with different combinations of horizontal alignment (variation of bends with respect to different curvatures). This study explores a methodology to evaluate the actual horizontal alignment of roads to increase the efficiency of highway management with respect to reducing travel time. In this paper after classification of all the design elements, the new concept of “curvature Index” (the degree of angle variation per unit length) is introduced to represent actual horizontal alignment of a road segment including number of bends and nature of bends. The curvature index measures analyzed were : bend density (number of bends per km); cumulative angle (degrees per km); mean angle (degrees); and standard deviation of angles. The research confirmed that driver's speed choices are more strongly related to curvature Index than curve design speed, and to the approach speed environment. The curvature index and operating vehicle speed is estimated using the database of GPS (Global Positioning System) receivers. GPS data is collected at selected road segments in Sri Lanka closely representing free flow condition. A methodology is developed to increase the reliability of GPS data obtained in order to investigate the relationship between curvature indexes and operating vehicle speed. Simple linear regression analysis is used to develop operating vehicle speed models, which related driver speed to the curvature Index of the highway. ArcGIS (Geographical Information System) provides a good platform to model relationship between curvature index and operating vehicle speed because the analysis tools in GIS can be directly used to analyze the GPS data.
item: Conference-Abstract
The cement stabilized soil as a road base material for Sri Lankan roads
(Department of Civil Engineering, University of Moratuwa., 2011-07) Bandara, WW; Mampearachchi, WK; Pasindu, HR
Dense Graded Aggregate Base has been used for road construction work in the Sri Lanka for many years. Rocks which are used to produce the aggregate are not available everywhere in the island. For example it is difficult to find suitable rocks in Northern part of Sri Lanka. Further, the available rocks are gradually decreasing due to the usage, land ownership and ecological issues. Therefore, cement stabilized soil can be used as an economically viable alternative material for the road base. Soils that can be stabilized are coarse granular, Sandy, Salty and Clayey materials. Coarse granular materials are not widely available in Sri Lanka. Sandy materials are freely available and give higher elastic modulus than Salty and clayed materials. Cement stabilized base need at least 97% compaction of maximum dry density. According to the findings during the construction, it has been revealed that the most practical thickness of the cement stabilized base is 200mm for achieving the compaction. In order to control shrinkage cracks, unconfined compressive strength at seven days is not more than 4 MPa. This can be increased to 6 MPa by providing an Asphalt Crack Relief Layer. For road pavements with stabilized base, critical tensile stress or strain is located at the bottom of the stabilized layer and the tensile stress should be limited to control the fatigue cracking for required number of axial load repetitions. Above mentioned limitations cannot be analyzed by the conventional Structure Number Based Pavement Design. Hence a Mechanistic – Empirical Method need to be used for the pavement design. This is difficult to carry out in general practice. Therefore, through our project Pavement design charts for the cement stabilized base with Sandy soil were developed by a Mechanistic – Empirical Method.
item: Conference-Abstract
Comparison of density specifications used for construction of hot mix asphalt (hma)
(Department of Civil Engineering, University of Moratuwa., 2011-07) Madhusanka, BS; Udakara, PAD; Hirimuthugodage, K; Mampearachchi, WK; Pasindu, HR
Measuring the density of asphalt concrete in the field is very important in quality controlling of the flexible pavements. Malpractices use in compaction of asphalt concrete in the field causes quality maintaining and durability problems in the Sri Lankan road system. In Sri Lanka Almost all the road projects use the Marshall Test Method to check the density of laid asphalt concrete. There are three methods for measuring degree of compaction of asphalt concrete in field; with respect to laboratory density, with respect to maximum density and with respect to a trial section. The objective of this research is to investigate the above three methods and select the most appropriate specification for quality control / quality assurance of HMA with further modifications to the prevailing systems. In order to accomplish the objective following methods were undertaken. Air void percentage and degree of compaction of asphalt in binder/wearing course have been calculated w.r.t. Marshall Density and Theoretical Maximum Density. The results convince that core densities should be lie within the range of 97.5-100% of the Marshall Density of the same asphalt sample, and 92-98% of the Theoretical Maximum Density to satisfy the air voids within the acceptable region. Since it is difficult to have a control strip in the field, nuclear density gauge (CPN-MC- 1DR-P PORTAPROBE) was used to check the density in the field. Observations imply that the number of roller passes need to be changed to maintain better quality in road construction.
item: Conference-Abstract
Comparison of density specifications used for construction of hot mix asphalt (HMA)
(Department of Civil Engineering, University of Moratuwa, 2011-07) Madhusanka, BS; Udakara, PAD; Hirimuthugodage, K; Mampearachchi, WK; Pasindu, HR
Measuring the density of asphalt concrete in the field is very important in quality controlling of the flexible pavements. Malpractices use in compaction of asphalt concrete in the field causes quality maintaining and durability problems in the Sri Lankan road system. In Sri Lanka Almost all the road projects use the Marshall Test Method to check the density of laid asphalt concrete. There are three methods for measuring degree of compaction of asphalt concrete in field; with respect to laboratory density, with respect to maximum density and with respect to a trial section. The objective of this research is to investigate the above three methods and select the most appropriate specification for quality control / quality assurance of HMA with further modifications to the prevailing systems. In order to accomplish the objective following methods were undertaken. Air void percentage and degree of compaction of asphalt in binder/wearing course have been calculated w.r.t. Marshall Density and Theoretical Maximum Density. The results convince that core densities should be lie within the range of 97.5-100% of the Marshall Density of the same asphalt sample, and 92-98% of the Theoretical Maximum Density to satisfy the air voids within the acceptable region. Since it is difficult to have a control strip in the field, nuclear density gauge (CPN-MC- 1DR-P PORTAPROBE) was used to check the density in the field. Observations imply that the number of roller passes need to be changed to maintain better quality in road construction.
item: Conference-Abstract
Comparison of transport-land use models
(Department of Civil Engineering, University of Moratuwa., 2011-07) de Silva, PCP; Bandara, JMSJ; Pasindu, HR
Over the last forty years, a variety of operational models has been developed and applied in the field of transportation and presently these models have become principal tools for strategic transportation planning. Once scholars started to point out that existing and future land use pattern exerts major impact on transportation and many of the issues prevailed in the cities at present occur due to the ignorance of the linkages of transportation and land uses, impact from the land uses and its changes is widely taken in to the transport modeling. Yet, lots of studies have shown there are shortcomings in the effectiveness of the transport models. Robert Cervero stated that “Hampering coordination is the reality that the benefits of careful transport-land use integration are often not evident until ten or more years in the future”. This paper examines the current status of the development of transportation modeling which considers the impact of land uses and its changes, and identifies the future developments of such models which are either likely or desirable. This paper reviews ten such models which are used widely in transport planning in the means of data and data types used, surveying methods of such data, data modeling methods, traffic assignment and travel forecasting methods, outputs generated, spatial techniques involved and user interfaces in relation to accounting the impacts of land use. Further, this research is a comparison study between different models in above means that finds out prospects and constraints of each model. Finally the paper gives a summary for the future developers of transport models and paves way to employ the prospects and to overcome the constraints of existing models in future models.
item: Conference-Abstract
Compensation systems for road accident victims
(Department of Civil Engineering, University of Moratuwa., 2011-07) Piyasekara, ARR; Kumarage, KAS; Pasindu, HR
Worldwide over 1.3 million Persons killed, 50 millions injured in 2007 due to road traffic accidents. In 2004,Road Traffic injuries was the ninth leading cause of death.By,2030 it is estimated the fifth leading cause of death, beating the rank of HIV/AIDS and Tuberculosis. Sri Lanka is experiences an increasing trend in road accidents during the last few decades. Ignoring safety hazards may lead to increase in the number of serious accidents. Collected data on accidents from the police and literature reveals several important issues in road traffic accidents and compensation process. Traffic accident victims suffer a great amount of damages. They are not only susceptible to bodily injuries but they may also succumb to financial problems arising from the hospital bills, medical treatment or rehabilitation. However, the trauma from such accidents seems to be immeasurable. As this trauma is often accompanied by pain, suffering and emotional distress, victims may not be expected to get on their feet as quickly as possible. Often times, after a traffic accident ,most victims are simply overwhelmed by the barrage of telephone calls, insurance paper work, accident reports, treatment costs, medical bills, paperwork and other correspondence. These may be too hard to handle for a victim who may want to rest and take a time off from distractions. Due to existing compensation system for road traffic accident victims in Sri Lanka, vulnerable road users are doubly vulnerable. Hence it is very important that the compensation systems and legal procedures should be simple and accessible to the victims of road traffic accidents. This thesis discusses the features of the post accident process, its impact on the road traffic accident victims and systems which are practicing worldwide to compensate road traffic accident victims.
item: Conference-Abstract
Cost overruns of foreign funded highway projects in Sri Lanka
(Department of Civil Engineering, University of Moratuwa., 2011-07) Hettiarachchi, HHNA; Mampearachchi, WK; Pasindu, HR
When an infrastructure development project is planned, an accurate estimation is critical. As a result of failing the fulfillment of expected accuracy, the cost overrun of the projects would result. The cost overrun is defined as a difference between the initial project estimate at the planning stage and the accounted project cost at the time of project completion. However, cost overrun is one of the major negative consequences that may influence to the economy of a developing country, like Sri Lanka. In order to fill the aforesaid financial gap, the necessity of pumping additional funds through the consolidated fund by the GOSL would be arisen. Out of the significant impacts of which caused by cost overruns in foreign funded projects are delay in completion and curtailment of original scope of work. But both adverse impacts are restricted by the conditions and policies of funding agencies. It is the normal practice that influencing to complete the project up to the agreed scope under the specified standards by the funding agencies. Due to the fact that the highway projects would make greater impacts not only to the development of infrastructure but also to the higher cost overruns, it was decided to limit the analysis only for the highway projects. The overlooked main factors that cause to turn the project into track of the cost overrun path are; ?Increase quantities ?Price Changes However, there can have many factors that have supported above mentioned main factors. The objective of this research is to ?To study what is cost overrun? ?To identify factors behind cost overruns in Sri Lankan projects ?To identify main risk factors & risk management The research would address the gap of knowledge of why highway projects overrun their cost. In addition to that, a method for minimizing cost overruns or identify cost overruns in advance will be proposed. In this research, twenty numbers of cost overrun highway projects completed within resent years and funded by different agencies were collected and analyzed. What are the main causes for cost overrun, how is a BoQ item correlate to each other item and what is relationship of cost overruns with project period or delay will be studied. This research highlights the significance of understanding proper risk allocation between contractual parties in Sri Lankan road projects by changing percentage of contingency component. It aims at assisting Sri Lankan road contractors and employers to a) Identify the risk sources inherent in road projects, b) Understand their risk responsibilities, c) Improve their risk handling strategies so that they would optimize the scarce resources d) Enhance the socio-economic value of Sri Lankan road projects. Constructions are rich with many difficulties and had made less attempt for risk analysis allows us to at least make an attempt to identify these risky projects and attaching some financial contingent value to recover the same. The project budget then becomes a more realistic representation to the client to afford it. Cost contingency is included within a budget to represent the total financial commitment for a project client and the quantum of such contingency is of critical importance to the projects. It is a normal practice that, maintaining 10% contingency for total cost overrun factors. But this thesis will prove that, it is incorrect and different allowances should be maintained. In this regards, the relationships are defined and they will be recommended to adopt.
item: Conference-Abstract
Development of transport infrastructure master plan for long distance travel
(Department of Civil Engineering, University of Moratuwa., 2011-07) Koggalahewa, MP; Wimalasena, MKKD; Dasanayaka, MGCB; Bandara, JMSJ; Pasindu, HR
Transportation is a facility which decides the level of achieving economic development in a country. Observing bird's eye view of the present condition in Sri Lanka it can be identified that transportation is currently suffering with many difficulties though the government is spending billions of Rupees on transport infrastructure development. The current road network has a higher density comparing to the other developing countries, but it is lack with mobility and higher level of service though it provides wider accessibility. Therefore the long distance travelling consumes more time than it requires. The railway system in the country has not extended after the colonial period. The railway system is lack of both mobility and accessibility. There is no clear plan to optimize railway system as a public transport service by connecting major cities and integration it with the road network with higher mobility to reduce the travel time. The present work describes a methodology which containing an integrated long distance transport network which reduces travel time while increasing mobility and accessibility. The research area covers the whole island by providing integrated rail and road system for the entire country. Data of the existing rail and road transport, land use data, traffic data, socio-economic data, future plans of infrastructure development, future plans of urban development and future plans of transport development were collected and analyzed to identify the existing and future demand centers of the country. Alternatives were evaluated with respect to travel time, environmental and social impacts and economic considerations with the help of GIS based analytical tool to generate optimum rail and road transport systems separately and integrated them to provide accessibility between transport modes to increase the efficiency of the system. The final outcome of this research is a transport infrastructure master plan for long distance travel which will provide an efficient system while increasing both the mobility and the accessibility of the transport system in Sri Lanka.
item: Conference-Abstract
Dynamic travel time estimation model for real time travelers
(Department of Civil Engineering, University of Moratuwa, 2011) Pilanavithana, US; Bandara, JMSJ; Pasindu, HR
A broad range of diverse technologies, known collectively as intelligent transportation systems (ITS), holds the answer to many of our society's transportation problems. ITS are comprised of existing and new technologies, including information processing, sensors, communications, control, and electronics. Combining these technologies in innovative ways and integrating them into our multimodal transportation system will save lives, time, and resources. Transportation is the backbone of our society—the movement of people and goods provides the foundation of our quality of life and economic prosperity. Various methodologies have been developed for dynamic travel time prediction. With the development of the Advanced Travelers Information Systems (ATIS), short-term travel time prediction is becoming increasingly important. As a key input for the dynamic route guidance system, travel time information enables the generation of the shortest path (or alternative paths) connecting the origins (or current locations) and destinations. Traffic estimation and prediction system (TrEPS) have the potential to improve traffic conditions and reduce travel delays by facilitating better utilization of available capacity. Moreover, a Short-term travel time prediction is incredibly significant to the real time travelers' information and route guidance system to hang on to the finest path during their route to the desired destination. In this research, to fulfill the first objective a model for estimating path flows and modifying O-D flows simultaneously is proposed based on probabilistic information (Route selection behaviour of drivers) and traffic counts. The probabilistic information is accumulated to obtain prior information on path proportions. The link traffic counts are used as sectional volume information of links. The proposed model is constructed as a two stage model. The first stage model is estimation model of path flows and the second stage model is modification model of O-D flows. Moreover, it was clarified that the proposed two stage model had enough ability to estimate path flows and to modify O-D flows accurately even when prior O-D flows had inconsistency with the current traffic conditions. By satisfying the Second objective, improved speed flow relationship employed which was focused on refining the speed estimates of network assignment models by using the modified Akçelik speed-flow model along with the literature findings. This Akçelik model produces significantly improved traffic assignment run times and provides more accurate speed estimates which lead accurate travel times to assure the last objective of identify the best path based on travel time using minimum real time information available. In Conclusion, the estimation of link flows and modifying the O - D flows can be performed by two stages modal and travel time will be projected by the improved speed flow relationship. Projected travel time facilitates the selecting best path or the alternative for the user destination. Furthermore, integrate a method which will automatically update the system data base with the latest traffic data corresponding to road links and give the most up-to-date best travel time path to the road user is proposed as future development.
item: Conference-Abstract
Effectiveness of rolling straight edge for quality control of asphalt concrete surfacing
(Department of Civil Engineering, University of Moratuwa., 2011-07) De Silva, MSK; Mampearachchi, WK; Pasindu, HR
Today in each part of the country, road surfacing is done by Asphalt Concrete. With the increase usage of Asphalt Concrete, the necessity of Quality Management System was arisen. Hence the Quality Management System for Asphalt Pavement was developed and established in following areas; 1. Plant operation 2. Asphalt Concrete transportation 3. Paving and Compaction 4. On finished Asphalt pavement To check the quality control on finished pavement, there are many parameters to be considered. One important parameter is Roughness value on the finished pavement. Different Technical Specifications provides various devices to quantify the Roughness value. One such method is to measure Roughness value using the Rolling Straight Edge. Here the dominant parameter is ups and downs of the road surface. Rolling Straight Edge equipment was used to count total ups and downs (Bumps) with magnitude of a particular length. A correlation between International Roughness Index and Rolling Straight Edge measurement has been developed using statistical analysis software SPSS. Most significant parameters for the roughness were identified and modifications to the specification were made. IRI = 1.662 + 0.02X; (X = Summation of the magnitude of the total bumps >=4mm) A case study on identifying the high roughness sections of a road was made and effects of remedial measures were analyzed using the developed correlation.
item: Conference-Abstract
Effectiveness of vehicle-actuated signals for at grade four legged intersections in Sri Lanka: a comparison study against existing fixed-time traffic signals
(Department of Civil Engineering, University of Moratuwa., 2011-07) Kamalrajh, A; Bandara, JMSJ; Pasindu, HR
The goal of traffic engineers in recent years is trying their best to get the most out of the systems that they develop. By designing most efficient systems, using the advancement of electronics the overall costs of transportation should be slightly easier to manage. In Sri Lanka, it is anticipated that the prevailing fixed-time traffic signals would be replaced by modern actuated traffic signals in near future. This study has been carried out to evaluate the efficiency of vehicle-actuated signals against prevailing fixed-time traffic signals prior to their implementation. Several existing signalised intersections in the capital city were carefully studied with their geometric and traffic turning movements. A traffic simulation was programmed in Microsoft Excel in such a way to generate traffic for a typical intersection in an urban area. In order to characterise real dynamic condition of traffic flow, various traffic volume combinations were selected among North-South and East-West through-traffic and other turning movements (Left-turns, Right-turns & Heavy vehicles) were randomised within their permissible limits. Numerous calculations for Cycle time, Vehicle-delay, Pedestrian-delay and Critical movements of different traffic combinations were computed by exploiting a renowned Australian Software called “Signalised (and unsignalised) Intersection Design and Research Aid [SIDRA]”. The outcomes of analysis were compared in graphical and tabular forms for the efficiency of fully- Actuated Signals against fixed-time Signals. It has been found that the replacement of fixed-time traffic signals with fully-actuated signals for stand-alone intersections shall not produce any major enhancement (reduction in delay) to the existing at grade four-legged intersections, which have three standard-approach lanes including right turn-bays with optimum length and two standard-exit lanes. Moreover, it is sensible that semi-actuated signals would be a better alternative for certain signalised intersections where major roads (continuous high demand) meet with minor roads (very stochastic or very low traffic demand).
item: Conference-Abstract
Evaluation of cost effectiveness of performance based maintenance contract
(Department of Civil Engineering, University of Moratuwa., 2011-07) Thennakoonwela, RMN; Mampearachchi, WK; Pasindu, HR
Road authorities around the world have been innovating and finding ways to cope with the high cost of road network maintenance, the growing demands of road users and the changing traffic type and volume. A well maintained road is needed to make the network sustainable for future generation. Poorly maintained roads constrain mobility, increase vehicle operating cost, increase accident rates and their associated human and property cost. Poor maintenance of the imposes heavy burden on the economy. However maintenance allocation for road agencies has steadily increased. There is a need of providing better value for expenditure, through higher level of service and low total maintenance cost. The objective of the study is evaluating the cost effectiveness of performance base maintenance contract especially provincial roads in Sri Lanka. Four types of maintenance methods were analyzed. Maintenance cost and condition of the road in each category were analyzed. It was found that Performance Based maintenance contract method performed well low cost and good road condition. The road condition is maintained at good condition relative to the other method with low maintenance cost. And it was also founded that developed formula can be used for the road condition, when the overall damage percentages of the distress are given. Road maintenance consist of several items such as maintaining of road carriageway (pavement), shoulders, draining stems, road signs & markings within the right of way. The research was focused on establishing a road condition rating index based on the road condition and analyzing the effectiveness of the maintenance standard, there are several types of Maintenance contracts, namely; Direct Labor, Contract, Performance based Contract and Performance based direct labour. Effectiveness of Maintenance standard in four contract method was analyzed using the road condition rating index and the maintenance cost. It was found in the literature that most of the countries use International Roughness Index (IRI) to evaluate the pavement condition and the standards have been based on the IRI value. However, provincial road development authorities in Sri Lanka are still not using IRI to select road for maintenance or rehabilitation. The selection of roads for maintenance is done arbitrary. Survey was conducted to find the maintenance standard used in provincial road development authorities. Currently, Western Provincial Road Development Authority maintains the roads under different maintenance standard. Performance Based Maintenance (PBM) standards have been introduced recently for the Western Province Roads network especially for foreign funded projects to evaluate their performance. In this research, pavement distress data were collected of selected road sections and the pavement rating of the selected roads by a panel consists of Engineers, technical officers and Technicians. The Collected data was analyzed using SPSS software. It was found that the r-squared value of the selected independent variables for the relationship was about 0.36 with the shoulder damaged, Since the shoulder damage has minimal effect for the condition of the carriageway, it was removed from the independent variables and R-Squired value of the relationship has been increased to 0.726 and the analyzed showed the significance of the selected parameters. Cost of the conventional maintenance methods are higher cost than the performance based method. It was shown that the rating of the road condition in performance based contract system is higher than the conventional methods used in this analysis. It is clear that, cost saving can be achieved under the performance based contracts.
item: Conference-Abstract
Evaluation of feasibility of polymer modified asphalt binders for Sri Lankan conditions
(Department of Civil Engineering, University of Moratuwa., 2011-07) Sitinamaluwa, HS; Mampearachchi, WK; Pasindu, HR
Polymer modification of asphalt binders has increasingly become the norm in designing optimally performing pavements. Pavements with polymer modification exhibits greater resistance to permanent deformation and thermal cracking, and decreased fatigue damage and temperature susceptibility. Polymer Modified binders (PMB) are effectively used in many countries, such as USA, Europe, Australia and India over last three decades to construct pavements with the superior performance and Extended service life. In Sri Lanka 80/100 and 60/70 penetration grade bitumen has been used and it is observed that both binders cannot perform satisfactorily due to their temperature susceptibility. Modification of bitumen decreases the temperature susceptibility and therefore now it's time to Sri Lanka to move forward from conventional binders to modified binders. Initial step of this research was to study about functionality of polymer modified bitumen and evaluating the need of polymer modified binders for Sri Lanka. After reviewing available data, it was identified that most suitable polymer modifiers for Sri Lanka are SBS, EVA, SBR, PE and Crumb rubber. Modification up to 4% - 8% of polymer is recommended and the modification level can vary with the desired properties of binder. That depends on the factors such as temperature, moisture level and other climatic conditions of the area and also traffic level. PMB has to be characterized differently from penetration grade bitumen and the improved performance properties are difficult to demonstrate with conventional empirical rheological tests. This research is focused on reviewing the available PMB specifications and finally come up with a set of required properties for modified binders relevant to Sri Lankan roads, required testing methods and handling procedures for PMB. The final outcome of this research would become a good initiating point for local highway engineers to move from conventional binders to modified binders.
item: Conference-Abstract
Evaluation of feasibility of polymer modified asphalt binders for Sri Lankan conditions
(Department of Civil Engineering, University of Moratuwa, 2011-07) Sitinamaluwa, HS; Mampearachchi, WK; Pasindu, HR
Polymer modification of asphalt binders has increasingly become the norm in designing optimally performing pavements. Pavements with polymer modification exhibits greater resistance to permanent deformation and thermal cracking, and decreased fatigue damage and temperature susceptibility. Polymer Modified binders (PMB) are effectively used in many countries, such as USA, Europe, Australia and India over last three decades to construct pavements with the superior performance and Extended service life. In Sri Lanka 80/100 and 60/70 penetration grade bitumen has been used and it is observed that both binders cannot perform satisfactorily due to their temperature susceptibility. Modification of bitumen decreases the temperature susceptibility and therefore now it's time to Sri Lanka to move forward from conventional binders to modified binders. Initial step of this research was to study about functionality of polymer modified bitumen and evaluating the need of polymer modified binders for Sri Lanka. After reviewing available data, it was identified that most suitable polymer modifiers for Sri Lanka are SBS, EVA, SBR, PE and Crumb rubber. Modification up to 4% - 8% of polymer is recommended and the modification level can vary with the desired properties of binder. That depends on the factors such as temperature, moisture level and other climatic conditions of the area and also traffic level. PMB has to be characterized differently from penetration grade bitumen and the improved performance properties are difficult to demonstrate with conventional empirical rheological tests. This research is focused on reviewing the available PMB specifications and finally come up with a set of required properties for modified binders relevant to Sri Lankan roads, required testing methods and handling procedures for PMB. The final outcome of this research would become a good initiating point for local highway engineers to move from conventional binders to modified binders.
item: Conference-Abstract
Evaluation of flood risk of transport infrastructure using GIS technology
(Department of Civil Engineering, University of Moratuwa., 2011-07) Prabath, WAK; Bandara, JMSJ; Pasindu, HR
Floods are not rare incidents in Sri Lanka. Historical record shows that Sri Lanka had experienced with many of catastrophic flood disasters. As a result of flooding, hundreds of thousands of lives, property, physical infrastructures are loss, damaged or destroyed. Especially, the transportation system & its infrastructure that includes roads & railways are frequently affected by floods. Neither a scheduled process nor any other resilience assessment plan or concepts to anticipate and reduce the impacts due to floods are available other than the traditional flood disaster management process of reconstruction. Hence, there is a need for an effective flood resilience assessment process to identify possible risks to the transportation system. Information such as terrain, rain fall, drainage pattern that are relating to the factors affecting flood risk on transportation infrastructure is available in scattered manner. However, this information has not been analyzed in an integrated manner to identify the flood risk on transport infrastructure. Identification of flood risk of existing and proposed transport infrastructure will be very useful to mitigate impacts due to any type of flood disaster. The paper presents a methodology developed to identify possible risk areas based on flood information available using Arc GIS platform. Data collection was done based on library & field surveys. Along with the literature survey relevant data such as flood records, physical infrastructures data, geographical & climatic data were collected and a GIS data base was prepared. A methodology was developed to identify possible disaster risk based on the information available using Spatial Analysis, 3D Analysis tools available in Arc GIS for the analysis and to produce results in map media.
item: Conference-Abstract
Evaluation of parameters influencing delays for road users at railway level crossings in Sri Lanka
(Department of Civil Engineering, University of Moratuwa., 2011-07) Weerakoon, J; Bandara, JMSJ; Pasindu, HR
Design, construction and maintenance of railway level crossings are responsibilities of Sri Lanka Railways. The funding agency in this regard is the Ministry of Finance where allocations are provided from the annual budget for above targets. The additional time consumption born by the road users at level crossing is a current issue to be addressed at the earliest possible in order to minimize the delay and inconvenience. According to the SLR the reason behind in this issue is the poor geometry & lack of maintenance. Further more the officials of SLR highlighted the lack of equipped laboratories or skilled technical staff for doing research and also the application of advance high tech equipment such as sensors and replaceable surface materials. One of the main reasons behind the said issues is the high capital cost of implementation of said needful. Under this research around 125 locations of level crossings were visited all over the country where the deficiencies and weaknesses influenced for delay was carefully observed. A random sample of 42 numbers of crossings (including good and bad sections) was selected for evaluation. The prominent causes detected were categorized for quantitative analysis. Few locations with high contribution on delay and safety such as Yangalmodara, Kolathenna, and Kapuwatta were taken as case studies and compared with some satisfactory level crossing such as Bentota. As the parameters such as number of rail tracks, traffic flows, type of crossings etc. defers from place to place it was decided to compare the delay per vehicle for 100m distance (50m distance from either sides of centre lines of the tracks) with the time taken by an average vehicle to travel the same distance in a particular location. Correlations were checked among the parameters. The gravity of causes was assessed by giving a rating (1-3) at different locations. Furthermore a number of discussions were made with the responsible officers of Sri Lanka Railway and Road Development Authority. With the help of the information gathered from the two organizations and also with the data collection and the evaluations carried out during the research it was able to forward some improvement proposals/ mitigation measures in order to minimize the delay at level crossings in Sri Lanka. It was found that the main parameters causing for this delay are visibility, surface defects and poor vertical alignment in approaches and in between tracks due to settlement or in proper designs implemented at level crossings.
item: Conference-Abstract
An examination of the appropriateness of flyovers as a traffic management measure to the road intersections of Sri Lanka
(Department of Civil Engineering, University of Moratuwa., 2011-07) Peiris, OV; Pasindu, HR
Traffic congestion and related issues are mostly common phenomena in most of the developing countries. There are different, location specific measures have been taken as solutions for decongestion at the urban intersections. One of the recent traffic management methods for congestion alleviation in Colombo City is the introduction of flyovers to important intersections at main road corridors. The importance of a flyover is its use of the vertical space which assumed that cause fewer impacts to the adjacent properties and the existing infrastructure. This study seeks to examine the level of success achieved through introducing flyover concept to the road intersections in terms of overall spatial development. It is argued by many people on the effectiveness of the flyovers, especially at road intersections such as Dehiwala, Nugegoda that their effects on the functional efficiency of the city through its mismatch between physical and design aspects. The performance of the recently introduced flyovers road intersections can be tested by comparing before and after conditions in relation to the overall expected achievements by using spatial parameters. Basically, accident counts, speed and travel time surveys can be used as the main evaluation criteria to test this at a particular location. Moreover, the variation of the pedestrian movement pattern, impacts on the trading activities and vehicular flow pattern after the project implementation can be used to evaluate the level of impact to the users at the location.
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.
item: Conference-Abstract
Franchising of long distance bus service in Sri Lanka in order to improve the quality of the service
(Department of Civil Engineering, University of Moratuwa., 2011-07) Karunarathna, PGC; Kumarage, KAS; Pasindu, HR
The topic consists with two main areas as franchising of long distance bus service and quality of the service. Long distance bus services are regulated by the National Transport Commission, and bus industry in Sri Lanka has passed mainly four periods, and it can be seen different services provisions in terms of management ownership and regulatory structure of the bus industry. But the problem is long distance bus services are not successfully providing a reliable ,safe and efficient service for passengers .The National Transport Commission is finding on possible ways of making balance with objectives of long distance the bus operator and the passenger in order to establish a reliable and sustainable long services .Sri Lanka has passed four periods of Omni bus services, and it can be seen different services provisions in terms of management ownership and regulatory structure of the bus industry. Although there is a period of 100 years old history of Omni bus transport in Sri Lanka, the country is not successful with providing a competitive service for passengers. National Transport Commission has drawn its attention towards franchising of long distance bus services helps to create a better path for an acceptable bus services for the three parties (passenger, operator and the regulator). The main objective of this study is to propose a suitable franchising system for long distance bus services and recognition of strengthens and weakness of existing reform of management of omnibus industry that is being made by the National Transport commission. Descriptive method is used for the study, and the conclusion is that the franchise system should be improved with new management system that is suitable to the country.
item: Conference-Abstract
GIS based classification system for low volume roads
(Department of Civil Engineering, University of Moratuwa., 2011-07) de Silva, SCP; Perera, L; Mampearachchi, WK; Pasindu, HR
In Sri Lanka, vast amount of infrastructure facilities have been built, still building, but yet no proper classification system has implemented sometimes. The road network in Sri Lanka is a classic example for this. Based on the current classification systems, roads are categorized as “A” class, “B” class, “AB” class and so on. There are many miles of roads that have been built, yet not categorized under any of these classes and remained for years without a category. Most of these roads are low volume roads and total approximated length is 70,000 km according to statistics. Planning is important for a country in many aspects. Specially for a developing country like Sri Lanka would definitely have a need for proper planning covering attributes such as financial, social, environmental and land use mix. Thus, classified road network comes into play where policy makers and planners can start thinking from transportation aspect because it is a well known fact that road network or the transportation system of a country is vital for its development. This paper presents a model for classifying low volume road network system using multiple parameters. The Kesbewa DS Division was taken as the study area for this research and first main parameter considered was the shortest distance and adjusted shortest distance. The Map of the selected area is adopted and regenerated in to feature solution of ArcGIS 9.3 and network analysis component of ArcGIS 9.3 is used to obtain the routes of each goal nodes and other nodes by selecting different parameters. The Network Analysis component has been implemented by Digistra Algorithm. The customization capability with programming language like VB 6.0 is used to develop a customized software component to gather all the possible links between each of two goal nodes and other nodes. The proposed software model presents the capability of finding the minimum path of any two nodes for each of factors, and also it is to possibility to compare two routes for particular two nodes relevant to the factors. The final outcome is also implemented to list out the all list of nodes with number of link usage at each route. This solution can also be extended to incorporate many other factors such as economical, road value, place of importance, land use mix, etc. depending upon the inherited values of considered area.

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