Browsing by Author "De SIlva, LIN"

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    Analysis of settlement monitoring data to assess the state of primary and secondary consolidation of soft organic soil deposits
    (Department of Civil Engineering, University of Moratuwa, 2012-12) Premalal, RPDS; Jayasinghe, TWASL; Indrachapa, KRTH; Thilakasiri, HS; Nawagamuwa, U; De SIlva, LIN
    Organic soil deposits under road embankments may cause consolidation settlement problems during the serviceability stage. It is not feasible to design road traces on such soil deposits using the traditionally used most unfavourable ground conditions. Instead the most probable ground conditions are used in the initial design and this approach is referred to as the observational approach. The risks associated with using most probable soil properties are managed by reviewing the initial design through the analysis of the observational data obtained during the construction stage. In this regards, analysis tools to assess the stability of the embankment during construction stage and the estimation of the degree of consolidation during ground improvement phase are extremely important. Even though there are large number of analytical methods available to use for the data analysis, not much research is done to identify the tools relevant to the organic soft soils found in Sri Lanka. This research is aimed at investigation of the analytical tools that can be used in the analysis of settlement monitoring data obtained during the implementation of the observational approach for construction of the road embankments over the soft soil deposits in Sri Lanka.
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    Failure analysis of a DBST road using mechanistic empirical method
    (Department of Civil Engineering, University of Moratuwa, 2012-12) Mampearachchi, WK; Marasinghe, DL; Dahigamuwa, RMTM; Wanniarachchi, WDNG; Nawagamuwa, U; De SIlva, LIN
    The objective of this research is to analyze a failure of a DBST road section using a Mechanistic - Empirical method. For this analysis, failure of A15- Trincomalee-Batticaloe road was selected.This particular road section was rehabilitated recently by extending the width of the initial road section from both the sides and soon, a large amount pot holes appeared in the newly constructed areas.Empirical methods alone failed to identify the reason behind this failure and therefore a Mechanistic - Empirical approach was used along with the KENLAYER software to analyze the section. Mechanistic approach to pavement design seeks to explain phenomena only by reference to physical causes. Thus it uses stresses, strains and deflections within a pavement structure to analyze the loads and material properties of the pavement. This study would help future engineers to identify the reason behind the failure of road sections. This will promote mechanistic softwares like KENLAYER and increase the usage of it. These softwares will make life easy for road designers and consultants and this may turn a new chapter in road designing of Sri Lanka.
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    Study on palmyrah as a reinforcement material
    (Department of Civil Engineering, University of Moratuwa, 2012-12) Baskaran, K; Mallikarachchi, HE; Jayasekara, MJPLM; Madushanka, GAT; Nawagamuwa, U; De SIlva, LIN
    Most developing countries Abstract: are confronted with acute housing shortage due to their over dependence on expensive, imported building materials. So there is an intense search for innovation of locally available, nature friendly materials.Palmyrah is widely spread all over North East region in Sri Lanka and has found use in many structural applications. This research explores the feasibility of using Palmyrah strips as an alternative for reinforcing steel in short span, lightly loaded slabs and beams.Structure of this research consisted of literature survey, testing mechanical properties of Palmyrah, basic design, construction and testing of Palmyrah reinforced concrete slabs and beams, analysing of results and recommendation.Static bending test, tensile test and compression test were conducted to identify characteristic strength and stiffness properties along with density and moisture content. Water absorption with time was also studied. Slabs and beams with varying reinforcement percentages were constructed and tested.Failure loads, crack loads, mode of failure and crack patterns of test slabs and beams were observed. Flexural capacity of concrete slabs and beams reinforced with Palmyrah strips was evaluated.lt was observed that Palmyrah reinforcement enhanced the failure load of the slab by 107% and failure load of beam by 370%. Experimental failure load of slab and beam averaged 140% and 164% of theoretically predicted value respectively. Both beams and slab had flexural failure by fracture of Palmyrah strips and their failure loads increased with increase of Palmyrah reinforcement.Thus it is concluded that Palmyrah strips has potential to be used as reinforcement in lightly loaded slabs and beams.