Faculty of Engineering, Civil Engineering

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item: Thesis-Abstract
A Critical review of mobilization advance payment and contractors' cash flows
Wijekoon, WMCLK; Perera, A
This research addresses the determination as to whether the Mobilization Advance Payment is actually necessary in the Sri Lankan construction industry, its effect on contractors' cash flow and whether it is a motivation for the contractors. Accurate cash flow forecasting is essential to all contractors in the construction Industry for successful operation and existence in the long run. At initial stages of a project the cash flow aspect of the contractor is negative. The main role of project financing is to cover up this negative flow in a beneficial, cost effective manner. Mobilization Advance Payment enhances the quality and productivity in the construction industry. It improves the performance and cost efficiency of the contractors as well as the clients. Cash data in relation to thirty projects were collected. Three criteria, no Mobilization Advance, 20% of the initial contract sum as the Mobilization Advance paid at the inception of the project and 20% of the initial contract sum as Mobilization Advance given in stages, were identified to determine the differences in the effects of cash flow. The effect of these different criteria on the cumulative cash flow was examined. Further Scheduled Performance Index was calculated for further analysis. Results show and confirm that Mobilization Advance Payment has a big bearing on the contractors' existence and their motivation towards attaining objectives of the project. Research confirms that Mobilization Advance Payment is a necessity in the Sri Lankan construction industry. Further it can be confirmed that the provision of Mobilization Advance Payment is very essential for the Sri Lankan contractors. Key Words: Mobilization Advance Payment, Cash Flow, Stage Payments, Scheduled Performance Index
item: Thesis-Abstract
A Fuzzy approach to handle uncertainty and vagueness in life cycle costing for air conditioning systems
Perera, RCR; Perera, AADAJ
Air conditioning cost being the most cost effective element of building services in buildings because of its higher operating cost. In order to select a cost benefited one among the available types a life cycle cost analysis can be applied. Life cycle costing (LCC) by its definition is totally based on predictions. Accuracy in its application depends on how far the predictions covers the reality, handles the uncertainties involved and ultimately how far predicting. There are five major variables that contribute to the operating cost as well as to the inaccuracy of LCC. Those are: indoor temperature; outdoor temperature; relative humidity; number of occupants; and period of operating. These variables inherit very high uncertainty and vagueness. Thus, predictions and decision making has to provide space for handling them. The fuzzy set theory is employed to handle the inherent uncertainty and vagueness of the human decision making process. Hence, the hypothesis of the research was "Fuzzy expert system will address the problem". Conducting interviews and questionnaire surveys, with air conditioning design experts, the knowledge for the knowledgebase and decision-making logic for inference engine of the system were established. Then the system was prototyped in MATLAB Rll TM. Traditional methods can process only descriptive data while fuzzy system can process both descriptive and non-descriptive (continuous) data and produce accurate output. For example, indoor temperature and number of occupants are changing almost every minute. This dynamicity is effectively accommodated in fuzzy membership functions. Since fuzzy systems can do multi-variant manipulating for sensitivity analysis, the contribution of all the input variables towards the output variable "change in operating cost" can be obtained at the same time. Finally, the developed system was tested for its accuracy in prediction of operating cost with data from hotel buildings covering the data taken from questionnaire survey and then with a real set of data to govern the whole system behavior. It exhibited 80% of accuracy. The thesis describes the approach, development of model and the testing in detail. Key words: Life Cycle Costing (LCC), air conditioning, uncertainties, vagueness, Fuzzy logic
item: Thesis-Full-text
A Hybrid approach to the representation and processing of design standards
Neilson, AI
This thesis presents an environment for the modelling and processing of structural design standards. This environment is known as SADA, an acronym for Standards Automated Design Assistant. SADA addresses many of the drawbacks conventionally associated with design standards and existing models of design standards. A study of existing standards models and design standards was carried out, which resulted in the identification of a number of key issues, including:  structural design standards are ambiguous and are therefore subject to interpretation;  structural design standards generally address standard or routine design contexts, existing standards models fail to recognise this;  existing models are generally opaque in nature: i. it is not clear to the user how the standards have been modeled ii. processing of the standard is a 'black-box' activity, furthermore; iii. users have no control over the modelling or processing activities. SADA consists of four main modules, each consisting of several components:  Code Information Base;  Processing Module;  Dependency Network Generator;  Design Case Base. Each module performs its designated tasks contributing to the overall functionality of SADA. Nurnerous standards can be encapsulated and. browsed in a hypertext manner within the SADA model. SADA supports the production of designs within the scope of the standards contained in the model. Standard and non-standard contexts are distinguished. A procedural approach is adopted for the production of standard or routine designs. Case Based support is provided for handling non-standard designs. A conformance checking facility is provided for designs produced within SADA, and independently. An applicability checking feature easures standards are not applied out of context. Various features giving the user control over the modelling and processing of the standards contained in SADA have been implemented.
item: Thesis-Abstract
A methamatical model study to forcast inflow to Senanayake Samudra
Dias, PPG; Kariyawasam, C
The Objective of this Study is to develop a Mathematical Model to Forecast Inflows to Senanayake Samudra, given the rainfall in its catchment. This forecast can effectively be used in establishing the reservoir operating criteria. The Model is a self cleansing one which will modify its basic parameters as new data are fed in. The Water Balance Equation is used to develop the Model. Original plan was to collect the rainfall data for the past thirty years of all the rainfall stations within and adjoining the catchment and characteristics of the basin. However the useful rainfall data were available only for the past five years. Hence the Monthly Model and the Weekly Model were developed with the available data.
item: Thesis-Abstract
A Methodology for design of pedestrian crossing facilities in Sri Lanka
Kaluarachchi, RASK; Kumarage, AS
Pedestrian accommodation should be an integral part of the design of any transport infrastructure project. It can be defined as walkways and pedestrian crossings Pedestrian have a right to cross roads safely. Therefore road designers have a professional responsibility to plan, design and provide safe walking and crossing facilities. Recent accident studies identified that pedestrian comprise a significant proportion of serious injuries and fatalities while they were crossing the road without using a marked pedestrian crossing. As the majority of pedestrian accident occur while crossing a road, the need of safe and efficient pedestrian crossing facilities could be the most important pedestrian safety factor. Sight distance, Level of Service and delay to pedestrian are major terms to be considered with warrants prior to installation of pedestrian crossing at a location of road being considered. Some time there would be additional delay and hazard by introducing crossing where it is not needed or is not suitable. Pedestrian characteristics and travel behaviour in the form of relationships among parameters such as speed, density, flow and space of pedestrian need to be identified by conducting further pedestrian surveys such as flow and travel time Design of a pedestrian crossing requires a basic understanding of related human characteristics and capabilities which are dependent on age, physical and mental condition of pedestrians, who are expected to use the crossing at that particular location. So the main aim of this study is to develop a guideline to assist in determining the appropriate crossing facility for a given location of a road based on the sight distance, Level of Service, delay to pedestrians and vehicles, pedestrian speed, density, flow and space in addition to the warrants. VI
item: Thesis-Abstract
A methodology for selecting and assigning contractors for construction projects in the Mahaweli Development Programme
Premakumara, HHP; Gunawardena, ND
Most of the construction works in the Mahaweli Development Project have been carried out through crash programmes. Even though, the project planning is vital for the economical and successful completion of any construction project this important aspect has not been given due recognition during the execution of downstream development works of the Mahaweli project. Instead of the proper project planning, the experience and knowledge of the Engineering staff with regard to the works and the performance of the contractors have been used for allocating works for the contractors. Although, this has resulted in achieving the targets of the scheduled programme, in many cases there have been failures too. Three models were developed for selecting and assigning contractors for three types of contracts used in the Mahaweli Development Project namely, Tendered Contracts, Fixed Rate Contracts and Labour Contracts. So far, no action has been taken to measure the performance level of the contractors and the performance standards to be maintained in respect of construction works in achieving the targets which are the main factors considered in the above models. As these are the most significant factors used in planning a construction project, this study reveals that the collection of performance data of contractors will be very useful in carring out future projects of similar nature. This research project also investigates the ways and means of determining the performance standards of different contractors as well as the standards of performance required by different construction activities for timely completion of the completion of the projects. Furthermore, recommendations are made regarding techniques that could be adopted for various types of contracts encountered in projects of a similar nature.
item: Thesis-Abstract
A New test for the evaluation of air classifier performance
McNabb, MB
sciency of mechanically extracting valuable resources from municipal solid waste (MSW). With today's techniques, resources such as combustibles, aluminum, glass, and ferrous materials can be extracted from ordinary refuse, processed, and returned to society for further use. This thesis examines one aspect of resource recovery engineering, namely the separation of MSW combustibles from noncombustibles by air classification. The combustible or organic fraction of MSW is valuable to society because it can be processed into refuse derived fuel (RDF) which power companies can mix with coal and burn in their combustion chanbers to create the steam that operates electric generators. Recovered combustibles are of greatest value when they are of high "purity" or rather are free from the contamination of noncombustibles, have a high energy value per unit mass, and require minimal processing. Problems caused by contaminants in RDF include glass slagging on the combustion chamber grates, increased residue left after burning, and a lowering of the RDF energy value.
item: Thesis-Abstract
A preliminary assessment of the Gal Oya water management project
Atukorala, NT; Kariyawasam, C
The Galoya Irrigation Project is the first multipurpose Scheme started in Sri Lanka. The project was commissioned in the year 1956. After nearly over 20 yrs. of its existence the project was in a rather poor condition. The original project served an area of 45,000 Acs, however after over 23 yrs, Irrigation facilities were available only for nearly 32,500 Acs for Maha & 19,250 Acs for Yala. The Gal Oya rehabilitation project was funded by the USAID and commenced in 1980 and continued beyond 1985. This study analyses the impact of the project on the work done from 1980 to 1985 (Most of the work was done during this period) The study was centered mainly on the aspects connected to irrigation as delving into other areas of assessment would be a vast exercise. The Irrigation aspect covered the following fields and the findings are. a. The Social Aspect With the rehabilitation programme there was a turn around of behavior of farmers. For example vandalism was reduced to almost nothing. No structures were damaged and no bunds cut. Third parties were not approached regarding water issues. Cultivation-calendar was adhered to as planned at the cultivation meetings. b. Water management and duty of water Rehabilitation of the project successfully improved a. The water conveyance capacity b. The water control capacity c. The water measurement capacity The foregoing enabled a very effective water management programme to be introduced and is being followed even today. This involved a computer programme with a very satisfactory feedback system. A number of water control structures were installed where necessary enabling the optimum use of water and preventing wastage. This measure improved the duty of water from pre-project value of 5.2 acft/Ac to the post project figure of 3.68 acft/Ac. c. Paddy production There was a gradual increase in the acreage and the Yield /Ac as the project progressed. The total acreage increased from pre-project 19,250 Acs Yala to post-project 53,000 Ac s Yala in 1985. Maha Acreages were pre-project 32,500 Acs to post-project 53,000 Acs. The increase in yield was pre project 34 bushels/Ac in 1979 to post project 60 bushels/Ac in 1985. The Yield is expected to increase further with the increase in confidence in the delivery schedules of water prompting greater agronomic imputs & increased labour inputs. Incidentally the yield in 1986 was 66.4 bushels/Ac. and in 1987 it was 70.5 bu. shels,/Ac. d. Economic Evaluation An economic evaluation was done taking into account only the increase in production of paddy and the .IRR was found to be 33.8%. However when the impact of the project as a whole is considered the fact that this project has raised the standard of living of the farmers within the project, created a sense of civic obligation among them together with a spin off of additional employment etc. cannot be underscored thus enabling this rehabilitation project as an example suitable for imitation in other rehabilitation projects to be taken up in the future.
item: Thesis-Abstract
A preliminary study of the spatial variation of rainfall and its effect on water management in the dry zone
Ravindra, PS; Kumaraswamy, N
Incorporating effective rainfall in irrigation water is an important task in water management. Understanding the climatic conditions is necessary to plan a raingauge network. The occurrence of thunderstorms is a main feature in the intermonsoonal periods. These convective storms are often highly localized and usually tend to be less than 8 km in width. Thus a fairly dense network of raingauges is necessary to get an accurate representation of the rainfall during these periods. However, when the rainfall is widespread, the maintenance of such a dense raingauge network is not essential. Paddy production in Sri Lanka is more influenced by rainfall in the Maha (October to February) season than in the Yala (May to August), as there is hardly any rain in the Yala season in most of the paddy growing areas. For the Maha crop, land preparation usually starts in October. About 28 percent of the annual rainfall occurs in October and November (second intermonsoonal period) and is mostly of the convective type. With a proper understanding of the areal rainfall distribution during this period conserving irrigation water is possible. The use of isohyetal patterns, correlation coefficient vs. distance diagrams and correlation linkage diagrams could be used to assess an optimum spacing between the raingauges. Using a triangular storm model, it can be shown that negative correlation values between pairs of raingauges, are due to smaller storm cells. Further, it can be shown when the storm width is approximately three times the width of the gauged area then no negative correlation can occur between the raingauges. A square grid of raingauges at about 2 km intervals is necessary during the period of the convective storms while a 14 km grid is required for the widespread monsoonal storm period. This study indicates an area where more research work is required for better water management and it is possible to achieve this within the normal level of management and would also yield considerable economic benefits.
item: Thesis-Abstract
A Review of standard method of measurements of building works - Sri Lanka (revised edition SLS 573)
Dilkumar, C; Kodikara, GW
Sri Lanka did not have a Standard Method of measurement of Building works until 1982. Various organisations have been using different methods. These were modified versions of SMM 4 and SMM 5 of RICS (U.K.), SMM prepared by HAW in 1968 and other methods developed by the organisations to suit the practices of local industry. To achieve the uniformity in the method of measurement of building works in the industry, the standard methods of measurement of Building works, SLS 573, was introduced in 1982. Now after twelve years ICTAD has revised this document and named it as SLS 573, Revision: 1994. This research was to identify the differences between the revision and the first SLS 573 and to get the responses of the industry regarding the major changes. In order to get the responses of the industry, questionnaires were sent to twenty four consultants and contractors. Also some formats of bills of quantities were studied in order to get the good aspects of them. Based on these responses it can be said that SLS 573; revision: 1994 is fairly accepted with some improvements. Due to the limitations of time only the major changes as defined in this study were taken into consideration and it is worthy to undertake a study to observe whether the industry accepts all the differences given in Appendix A.
item: Thesis-Abstract
A Study of behaviour of high rise buildings with transfer level under dynamic loading
Jayasundara, TJ; Jayasinghe, MTR
Earthquake resistant structures are not mandatory in countries located away from earthquake prone zones such as Sri Lanka. However after the occurrence of 2004 Tsunami, and considering possible environmental changers and recently observed small scale ground motions, it is advisable to consider Sri Lanka as low seismic zone. With the current trend of "Mixed Development Concept" high- rise buildings with transfer plates are common form in the vicinity as far as apartment buildings are concerned. The consequences in an event of an earthquake can be serious or even fatal for this type of highly irregular buildings and adoption of earthquake detailing alone would not adequate. Therefore, approach is needed in order to enhance the earthquake resistance at the conceptual design stage. This study has been carried out in order to identify the effects on the seismic performance of the building when the level of the transfer plate changes. Accordingly, five number of thirty five storied apartment buildings with transfer plate located at different levels were considered in the analysis. It is observed that building codes provide criteria to classify the vertically irregular structures and suggest dynamic analysis to arrive at design lateral forces. In this context, the buildings under this study were subjected to response spectrum analysis according to the design spectrum given in the UBC 97. Computer simulation has become an efficient tool in the analysis of structures under extreme loading. Therefore, three dimensional computer models generated with the help of SAP 2000 were used in this study. The transfer floor was located at the tenth floor level of the thirty five storied building as the first case. The analysis was repeated by changing the level of the transfer plate to below and above the tenth level. Results obtained for buildings with transfer plate located at different levels were compared. From the comparison of Response Spectrum Analysis results of this study it , was found that, when the level of the transfer floor moves towards the ground it enhances the earthquake resistance of such buildings. Further, it was found that the variation of the base shear, maximum absolute accelerations, maximum absolute displacement and the inter story drift is marginal with respect to the change in level of the transfer plate for this particular building.
item: Thesis-Abstract
A study of built - up timber structural elements
Mohanathevan, S; Hettiarachchi, MTP
Code on timber design CBS 5268 Part 2, 1991) gives no provisions for the design of layered braced and box timber columns except spaced timber columns. Very little information is available about these in the literature on timber structures. This paper provides procedure for determining the axial load capacity of mechanically connected built-up columns, such as layered columns, spaced columns, braced columns and box columns. In addition to that, it gives information about nail connection details and arrangement. Mainly concentrated on built-up timber columns made up with mechanical connection as it could be done locally. The theoretical development takes into account the effect of columns stability and effectiveness of the shear transfer. The experimental results obtained by under graduate students are compared with theoretical predictions. Conclusions are drawn with regards to the suitability of the design methods for built up timber columns made by nailed connections.
item: Thesis-Abstract
A Study of customer satisfaction and application of QFD for quality improvement in residential apartments
Samarajeewa, KGA; Gunawardena, ND
There has been a significant growth in the residential apartment market in Sri Lanka during the last decade. The main reasons behind this upsurge include the growth of population, changes in living patterns and the soaring prices of property particularly in urban areas of the country. Sustainability of this segment of construction depends to a greater extent on the ability of developers to satisfy customer requirements in the long run. At present, most of the residential apartments are designed without the involvement of potential users or customers. When there is a communication gap among the parties, particularly with respect to user requirements, the goal of customer satisfaction and high quality services cannot be achieved. To ensure defects free and user-friendly form of residential apartments, the right blend of design, construction and operation phases is vital. This study has analyzed the information obtained through questionnaire survey to measure occupants' perception of characteristics of their apartment and its surroundings in terms of both 'importance' and 'quality'. The analysis considered both the private and public sector apartments and its process, critical issues regarding housing and customer attitudes were identified. Further, the results of the study revealed that understanding and determining the real customer requirements are essential for the sustainability of the residential apartment business; to address this issue, Quality Function Deployment (QFD) technique could be used quite successfully and if there is a mechanism to listen.to the voice of the customers such as the Post Occupancy Evaluation (POE) surveys presented in this research or any other that enables the involvement of users during the early stages. Key words: Residential apartments, Quality, _.Customer satisfaction, Post Occupancy Evaluation, Quality Function Deployment
item: Thesis-Abstract
A Study of irrigation water use for paddy cultivation in the dry zone of Sri Lanka
Wickramaarachchi, TN; Wijesekera, NTS; Gamage, NPD; Senarath, DCH
Water is a scarce resource in the Dry Zone of Sri Lanka and it is a major problem faced by the cultivators in the area. Since their cultivations totally depend on irrigation water, every possible effort should be put in order to optimize the water usage to achieve increased crop production. Recent reports on water management activities of several irrigation schemes in the Dry Zone indicates that the water distribution is not meeting the demands of farmers in terms of adequacy, reliability & timeliness. Further it was said that there is considerable potential to increase paddy yield in this system through improved irrigation water management, especially by efficient irrigation scheduling. Following four study areas in the Dry & Intermediate Zones were selected from different irrigation schemes authorized by the different organizations. i) Block 404 & 406 of Mahaweli system H ii) Track 1 of Rajangana Irrigation scheme iii) Ridi Bendi Ela irrigation scheme The strengths and weaknesses of the presently adopted water allocations by the above schemes were identified. Further, the cultivation practices and present water usage in three irrigation schemes were compared. The irrigation requirements according to the Irrigation Department guideline recommendations were computed for each scheme using a spread sheet model and compared with present water usage in three schemes to find out optimum solutions for irrigation water use for paddy cultivation. The comparative analysis revealed that the practices adopted in issuing water in each scheme differ resulting disparity in water usage, farmers' satisfaction on water issues and paddy yield. Considering the above comparisons, the recommendations for water issues during both land preparation & crop growth in paddy cultivation were presented pertaining to the most appropriate date of commencement and duration of the land preparation, the variation of depth of water application and frequency of irrigation during different growth stages of paddy with possible water saving techniques incorporating farmer needs. The optimum quantity of water requirement for the land preparation with maximum utilization of rainfall, most favorable quantity of water to meet the crop water requirement at different growth stages of paddy and the selection of best canal grouping to optimize the water distribution were also presented in the study.
item: Thesis-Abstract
A Study of pedestrian safety in Sri Lanka
Fernando, MBS; Kumarage, AS
Pedestrian fatalities in Sri Lanka account for 40% of all road deaths. In Colombo district this is as high as 70%. Of all casualties of road accidents, pedestrians constitute 39%. The majority of the victims are in their prime age of between 20 to 35 years. (Police Accident Report, 1996) According to the Ministry of Health, among the leading causes of hospitalization, accident injury is ranked second highest. (Health Bulletin,1995). A survey conducted at the National Hospital, Colombo, reported that victims of road traffic accident occupied 24% of the beds in the accident ward. The cost of traffic accidents has been estimated to be 0.5 to 1 percent of GPD. (Fernando & Fernando,1994). In industrial countries road traffic accidents have long been recognized as a major cause of death and more emphasis on protecting the most vulnerable road user, particularly the pedestrian. Unfortunately, Sri Lanka has followed the pattern of developing countries where resources have been spent on improvements aimed at helping the motorist rather than the pedestrian despite the high involvement of pedestrians in traffic accidents. However, concern for vulnerable road user has been growing recently among the highway engineers in Sri Lanka and attention is now being focused on pedestrians and pedal cyclists.
item: Thesis-Full-text
A Study of the Negombo lagoon with respect to the salinity variation and pollution of the lagoon water and effects of proposed dredging activities
Malawaraaratchi, RN; Rathnayake, N; Samarawickrama, SP
Negombo Lagoon is a shallow basin estuary, located on the West coast of Sri Lanka, serving important functions including fishing and tourism. It drains water carrying nutrients and organic matter from the heavily populated catchment area and has faced the threat of the degradation of water quality. The objectives of this research are to study the seasonal and diurnal variation of salinity in the estuary, study the pollution status of the estuary; study the effects of dredging on the water quality and to recommend remedial measures. 17 sampling locations were selected for the study, which included points in the estuary and fresh water feeders. A Sampling programme of 6 days which covered both wet and dry weather as well as the spring and neap tidal periods was carried out. Salinity, nutrients and COD were measured at the flood and ebb tides. According to the salinity measurements, in the dry period, the estuary is fully mixed. Stratified conditions occur when the fresh water flow rate increases. Chl a measurements were used to assess the trophic state of the estuary and fresh water feeders. The estuary is eutrophicated both in the wet and dry periods and some locations are even hypertrophic. Out of the fresh water feeders, Hamilton canal is mesotrophic and has faced the threat of eutrophication. According to the literature, limiting potential of the tropical estuaries has been found to shift from N to P with higher fresh water flow rates and results of this study agree well with the above finding. Limiting P inflows is a remedial measure to improve the water quality. Where the loads of DIN and TN are concerned, Dandugam-Oya was found to bring the highest loads irrespective of the climatic conditions. Where the Phosphate loads are concerned, Ja-ela brings significant, constant loads on rainy season, while Dandugam-Oya brings the highest load with the highest flow rate. Out of the 7 dredging options studied, option 6 is the most feasible one.
item: Thesis-Abstract
A study of the present and potential in Sri Lanka
Pattiaratchi, DS; Madusuthanan, N
The Government had initiated a National Agricultural, Food and Nutrition Strategy to-assess Sri Lanka's agricultural and food situation and establish priorities for sectoral development. Since the plan involves the use of land, a computerized Land Information System was set up to facilitate the analysis and evaluation of Land use in Sri Lanka. A Radio Shack Model II micro-computer was used for this purpose. Data on Soils, climate, topography and present land use were fed into the computerized data bank. The grid cell system of data storage was used. The dimensions or a grid cell are 1.05 x 2.1 Km covering an extent of 224 hectares. The final maps are plotted to a scale of 1:500,000. The soi1 data were obtained from the manuscript copies or reconnaissance soli maps drawn to a scale of 1:63,630 available at the Land Use Division. The climatic data were obtained from the agro-climatic data and rainfall probability maps produced by the Land and Water Use Division in 1976 and 1983 respectively. Slope data were compiled with the help of contour Lines on Topographic maps of scale 1:63,360. Data on present land use were obtained from three sources viz. (a) Survey Department (1981) 1:100,000 and 1:50,000 scale maps of Polonnaruwa, Batticaloa, Kandy and Colombo(final maps) and Puttalam, Gampaha, Kegalle, Kurunegala, Badulla, Ampara and Matale Districts (prelimlnary maps) (b) Land Use Division (1980 to 1983) 1: 63,360 and 1:50,000 scale maps of Matara, Nuwara Eliya, part of Ratnapura and Hambantota Districts(c) Huntings Survey Corporatlon (1956) 1: 6 3,360 scale maps for the balance Districts updated by date from Topographic sheets of 1970s and data on Irrigation schemes implemented by the Irrigation Department and Mahaweli Authority. Data on soils, climate and topography were assessed to determine suitabilility of lands for (a) rainfed annual crops (b) irrigation upland annual crops (c) rainted paddy under puddle conditions (d) irrigated paddy under puddled conditions (e) rainfed sugar cane (f) irrigated sugar cane (g) rainted minor perennial crops. Four classes of suitability as recommended in the FAO Framework for Land Evaluation Viz S1Highly Suitable, S2 Moderately Suitable, S3-Marginally Suitable and N Unsuitable were recognized in this exercise. Tables of district wise of land suitability classes were also complied. Secondly the present land use was analyzed with respect to the suitability classes. The map complied for this purpose shows locations at which the analyzed land use is practised giving the symbol of the suitability class. A table giving the district wise extents is also complied. Thirdly the potential locations for expansion of the considered land use is compiled. Only locations of class S1 and S2 suitability are considered. Lands under forest reserves, wild life parks, land earmarked for Mahaweli and other development projects and other reserves are shown with separate symbols F, P, M, D and R respectively for class Sl lands and f, p, m, d and r for class S2 lands. A districtwise extents table too is compiled.
item: Thesis-Abstract
A Study of the present status of management of PCBs, and development of a preliminary inventory for PCB contaminated transformers in Sri Lanka
Panditharatne, CR; Ratnayake, N
Polychlorinated biphenyls (PCBs) have wide applications and one of its main uses is as the dielectric fluid in electric equipment. During 1970s PCBs were identified as a substance dangerous to health and environment and was banned in most countries since 1980s. Assuming that 60% of its uses are as dielectric fluid in electrical equipment, this survey was concentrated on transformers. In Sri Lanka, CEB, LECO, LTL are the main service sector stakeholder agencies that own and manage transformers and capacitors that could be contaminated with PCBs. Other than these institutions there are transformers owned by private sector users. Small scale recyclers also handle transformers for smelting of copper and recycling of waste oil. The objective of this study is to estimate the extent to which there are PCB contaminated equipments in the country; to identify issues faced by stakeholders and to provide recommendations for the management of PCB contaminated equipment. Questionnaires, surveys and field visits were undertaken for the collection of information. In the survey, information about transformers manufactured on or before 1986 were collected. There are 14,354 transformers owned by CEB and 2700 owned by LECO. In the survey, 354 in-use transformers and 296 decommissioned transformers were investigated. 118 In-use transformers were tested with the Dexsil Field Test Kit and 52 decommissioned transformers were tested. Dexsil Field Test Kit was used to eliminate PCB negative transformers. In Sri Lanka, there are a few pure PCB transformers, but a considerable potion of contaminated mineral oil transformers exist in the country. According to the findings of the study, with 95% confidence level, it can be stated that 73% to 56% of in-use transformers in the population are contaminated with PCBs, while at the same confidence level, 78% to 52% of decommissioned transformers are contaminated. There are several HS codes under which PCB oils, contaminated material and waste oils could be imported to Sri Lanka. There is no legal requirement for a 'PCB free certificate'. Possibility of informal recyclers being contaminated with PCBs is quite high because there are no controls over disposal of PCB contaminated transformers. Recyclers are completely unaware about the hazards of PCBs. Storage of contaminated transformers/material is not environmentally acceptable and there is a high possibility for environmental contamination. Main recommendations of the study; 1. Establishment of a complete Inventory and a Database on contaminated transformers. 2. Identify all Pure PCB transformers and have a phasing out plan. 3. Establish procedure for Operation and maintenance of contaminated transformers to prevent further cross contamination. 4. Prevent new entry of contaminated capacitors, transformers and oils to Sri Lanka 5. Proper disposal of decommissioned transformers. 6. Establishment of proper storage; identification and remediation of contaminated sites. 7. Establishment of necessary regulations for the implementation of the above.
item: Thesis-Abstract
A Study of the sustainability of a water supply scheme utilizing a costal aquifer with particular reference to the Koggala export processing zone
Mahinda, AKA; Senarath, DCH
Koggala Export Processing Zone of the BOI was setup in 1991 and functions with 20 Nosfactories and work force of over 10,000 in the Galle district just adjacent to the sea andcoastal belt. Total extent of the KgEPZ area is 225 Acres. Since there were no surface waterscheme to provide the required water for this project, a groundwater scheme was consideredas an appropriate alternative resource. NWS&DB has plan to supply water from the TalpeReservoir of Gin Ganga Project (KfW) with part of the cost shared by the BOI.The purpose of this study is to study the sustainability of the existing water supply schemein Koggala EPZ where a coastal aquifer is used as the source. Since about 50% of the landare vacant and could be given for future investment projects in the KgEPZ, the possibilityof continuation of operation of existing groundwater scheme supplemented with surfacewater supply is considered as an economical solution for the KgEPZ.For estimation of recharge water balance calculations were done for time step of 1 day,since in a time step of 1 day would capture all the relevant changes that occur.This study estimated that recharge to the aquifer is 0.4 Million cubic metres per year whichis equivalent to 357 mm/year.n
item: Thesis-Abstract
A study on costs of quality in building projects
Wickramaarachchi, MMP
The knowledge of quality costs makes the difference between costly way and beneficial way in achieving quality. These include costs associated with the achievement or non achievement of product quality as defined by requirements established by the company and it's contracts with customers and the society. Such quality costs are made up of three components namely prevention, appraisal and failure costs. Prevention cost is the cost of any action taken to prevent the risk of defects. Appraisal costs incorporate costs of evaluating the achievement of quality requirements such as inspection and testing performed at any stage. Losses associated with nonconformity/defects will accumulate as failures that detected during the process through inspections (internal failures such as rework) or once the client has accepted (external failures such as claims and replacements). Economic logic of above quality cost categories is to allow minimal quality cost applicable to each company by constructing a self correction quality cost system which will seek optimum cost for any business situation. Literature shows that quality costs make up 8-15% of total construction costs and most contractors can cut 25% of costs of buildings from a good quality cost management program. Hence, the problems of quality and related costs has been of a major concern to any building contractor running on a restricted budget. And it applies to clients/developers and society as large as much it does to builders. The research reviews the use and significance of issues of cost of quality in construction and concludes with a precise of a survey done on the usage in actual practice to get the perception of the industry on quality costing. It is aimed to device an appropriate strategy to improve the quality of strategic decision making as well as with regard to quality cost management in an uncertain and risky environment in firms. A simplified model (COQQS) is developed to assess the costs of quality that is incorporated in a software tool called "contractor's guide ". The proposed model (COQQS) consisted of an improvement made to the Quality Cost Matrix for quantification and handling based on the Quality Cost Model and reviews done by Abdul Rahman (1997). In Case Study-I, the contractor had incurred nearly Rs.125Million as the quality and related costs that contributed 17.66% to the actual work done. Out of total quality costs failure costs represents nearly 90 % whilst weight given to prevention/appraisals is 10 %. Prevention has got the least priority (less than 3%) of the costs expended for the project. The highest frequency of quality failure against the type of associated cause was for design • rl) related issues. Similarly communication problems, planning and coordination, subcontractor related, construction, material/plant/labour related issues, client interventions and third party/othercauses had accounted for high frequency of occurrences respectively as the causes of quality losses. The cost effect on above was analyzed in a pareto diagram, giving the direction to which areas to consider most in terms of both cost effect and frequency of occurrence.In conclusion, it suggested that an increase on prevention activity would make thesecosts minimized, thereby achieving an optimum level in efficiency and effectiveness of operations. In that regard, the need for a structured and formal system of quality cost management to address the aspects of performance has arisen as a direct result of deficiencies and problems in design, construction, materials, workmanship, cost and time overruns. Thesimilar conclusions were made in Case Study -2 which involved construction of a power stationthat incurred Rs 28 million as mere quality losses comprising 13 % contract sum of Rs 54 Million ( for the reference period of 6 months) as quality costs consisting 99% cost on qualitylosses and less than 1% on prevention and appraisals quality costs. This represented a 50.4%cost on quality failures and related costs making a 33.54 % contribution of total cost occurredon project to the contractor so far during the study period. According to the pareto chart, both projects had a significant contribution of quality costs due to design and constructionrelated issues. The simplicity that was enough to validate the significance and consequences of quality costing is a key feature of these cases. This would unveil the gap of the absence of quality related cost data in Sri Lankan construction sector to a certain extent. Specially the failure cost, which is avoidable is researched further to identify steps to be taken to tackle problems offailure and other quality costs The possibility of application in Sri Lankan context as a tool is highlighted from key findingsmade on the survey. The feedback of a questionnaire survey and interviews were used to get an idea on Sri Lankan construction industry, conceptual application, opportunities, constraints and obstacles over the suggested system for "quality cost quantificationand collection". A system was proposed to trace the position of a company in the process of development of quality system in terms of both quality management and qualitycost management. Accordingly, the survey on the adoption process for a case study finnrevealed that the firm was still in the initial stage of development of quality management systemusing tools of quality costing. Further, several applications of the model and future workahead are identified to present conclusions and recommendations.