Browsing by Author "Widanagamachchi, UC"

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item: SRC-Report
Foundation improvements for walls with hand moulded chip concrete blocks
Jayasinghe, MTR; Widanagamachchi, UC; Nandaweera, HP
The need to search for alternative building materials is quite important in today’s context with serious problems associated with clay and sand mining. Mining of clay for manufacturing of bricks have caused severe degradation of valuable land and this has also led to the lowering of water table in these areas. Sand mining is also a serious problem that has seriously undermined the possibility to provide potable water due to intrusion of salt water. It is also desirable to reduce the use of brickwork in the present context since it uses bricks and sand extensively. In addition, brickwork requires plastering which also needs a considerable quantity of sand and lime. Thus, brickwork can be considered as an expensive form of construction with respect to the cost and also due to the associated environmental problems. An alternative to such drawbacks is chip concrete blocks with a thickness of 125 mm. These blocks can be manufactured as hand moulded (hand moulded chip concrete blocks - HMCC). These blocks are particularly suitable for rural areas of Sri Lanka where there are many self help housing projects funded by the governmental and non-governmental organisations. Since these blocks could be used to construct houses at various areas of Sri Lanka, it is useful to develop a cost effective foundation system that can be used with a weak soil.
item: Thesis-Full-text
The Labour motivation of construction industry in Sri Lanka
(2015-02-23) Widanagamachchi, UC; Ekanayake, L
Construction is the fourth highest sub sector in Sri Lankan economy which contributed 8.1% of overall GDP in year 2012. Labouer is an important resource in construction because it is the one that combines all the other resources namely materials, plant and equipment, and finance in order to produce the various construction products.Labourers on civil engineering projects are frequently confronted with problems that could lead to demotivation; thus, join and retain them in construction field in Sri Lankais a key challenge. Thus, the research problem is articulated for this study as:why construction labourers do not motivate to join and retain in the construction field in Sri Lanka? Survey research methodology was used to investigate the research problem. Structured questionnaire was used data collection in this study. Sample of 60 construction labourers was obtained across construction sites of ICTAD certified medium scale construction companies, which are located in Colombo area in Sri Lanka. The phenomenon of ‘labour motivation in construction’ was examined through self-administered questionnaire. Percentage and Relative Important Index (RII) data analysis techniques were used to analyse the data. The results indicated of top six significant factors for lack of motivation for construction work force: lack of income; poor retirement benefits; difficulties in understanding technical drawings; temporary nature of the job; hard working; and, lack of social recognition; thus, most important demotivating factors in the eyes of construction workers in Sri Lanka. Mitigating these de-motivators through effective motivation strategies will increase motivation of construction labourers to join and retain in construction field; thereby, improve productivity of construction work force.
item: SRC-Report
Use of hand moulded chip concrete blocks for single storey houses
Jayasinghe, MTR; Widanagamachchi, UC; Kapuruge, SL
Sri Lanka is at present facing serious environmental problems due to over-exploitation of its natural resources as building materials. The examples are the problem associated with sand mining and clay mining. Sand is extensively used for brickwork construction. Clay is used for manufacturing of bricks. Therefore, there is an urgent need to find alternative building materials that can reduce the use of these depleted natural resources. In this context, hand moulded chip concrete (HMCC) blocks can play an important role. It can reduce or eliminate the use of sand by using quarry dust and chips; both are by products of metal crushing industry. These blocks can be manufactured to any desirable width since the width of the mould can be adjusted. Thus, it is possible to anufacture 125 mm and 100 mm blocks that can be used for external and internal walls, respectively. These thicknesses are allowed according to the building regulations. It is also possible to give a reasonable finish so that there is a possibility to avoid plastering. With a detailed experimental study, it is recommended that 1:8:14 cement, fine aggregate and chip mix could be used for manufacturing of the blocks. As the fine aggregate, sand or quarry dust can be used depending on the availability. It can give a strength in excess of 1.2 N/mm2 recommended in SLS 855 : Part 1 : 1989. It was found that a characteristic strength of 0.9 N/mm2 can be safely used for the block walls constructed with HMCC blocks. This is a strength sufficient for majority of probable load cases that occur in a single storey houses. A cost study carried out has indicated that the hand moulded chip concrete blocks can have a cost comparable with these available in the market. Since these blocks can be cast by the house builder at the site, it would be advantageous for rural communities who depend on small loans or grant for the construction of the houses, given by the governmental or non-governmental organizations.