Civil Engineering Research for Industry Symposium

Permanent URI for this communityhttp://192.248.9.226/handle/123/18175

Browse

Browsing Civil Engineering Research for Industry Symposium by Author "Baskaran, K"

Filter results by typing the first few letters
Now showing 1 - 5 of 5
  • Thumbnail Image
    item: Conference-Full-text
    State of the art of concrete paving blocks in Sri Lanka (CPBs)
    (Department of Civil Engineering, University of Moratuwa, 2011) Baskaran, K; Gopinath, K; Ratnayake, N
    It is in the last five years that the stakeholders of concrete paving blocks (CPBs) are awakening to engineer the CPBs in Sri Lanka. Although large scale production of CPBs has already flourished in Sri Lanka, their adherence with stringent standards (both Sri Lankan and International) remains dubious. This reluctance to meet the performance and durability criteria according to codes of practices, curtails the life span of concrete block paved roads to a greater extent. The scope of the present paper is limited to verifying whether the local concrete paving blocks are made on par with international standards. Sample blocks were obtained from local CPB manufacturers and investigated.Though these blocks met the criteria in Sri Lankan Standard for CPBs for strength classes 2, 3, 4 roads, none of them met the compressive strength criteria for strength class 1 roads. Besides, tensile strength requirement specified in the BS EN 1338: 2003 was met by none of the blocks tested. Since, Sri Lankan Standard is planned to incorporate splitting tensile strength as the dominant measure to assess paving blocks in the near future, this study also attempted to identify a mix proportion to meet the splitting tensile strength requirement specified in BS EN 1338: 2003. When CPBs were casted using CPB making machine, an intolerable strength deviation was observed. A series of tests were conducted to explore the reasons for this.The outcome of which would help the small scale manufacturers to keep strength variations within a tolerable range, when they are using CPB making machines.
  • Thumbnail Image
    item: Conference-Full-text
    Strength assessment of steel towers
    (Department of Civil Engineering, University of Moratuwa, 2011) Baskaran, K; Jeneevan, G; Jayasinghe, JPLM; Hettiarachchi, HHANC; Ratnayake, N
    In the recent Abstract: past, considerable number of tower failures happened in telecommunication sector and power transmission sector in Sri Lanka. However, no lessons were learnt and there is still a vacuum in strength assessment of towers. The objectives of this research are conducting data survey on failed towers in Sri Lanka and identifying causes, analysing failed electric transmission towers using finite element analysis and finding the causes for the failures and developing simple methods to check tower capacity based on available simplified models. Four telecommunication towers and a transmission tower were considered to identify the failure reasons. Structural analysis of a transmission tower was done using a finite element analysis package, SAP2000. A manual method to analyse 3D trusses was developed by combining unit load method and tension coefficient method. To ensure the validity of proposed analysis methods, a simple tower model was erected, structural analysis was done using both SAP 2000 package and manual method, failure loads were predicted using SAP 2000 package, loading was conducted and results were analysed. It is concluded that preliminary structural analysis with a specialised or a common structural analysis package, has to be incorporated into prevailing steel tower design procedures. Frequently admitted reason for telecommunication tower failures is tornados. However, nowadays towers are being overloaded with antennas without proper consultation. Therefore it is essential to carry out a detailed technical failure analysis to identify the reasons of failures. All these procedures and results obtained are discussed in detail in this paper.
  • Thumbnail Image
    item: Conference-Full-text
    Strength enhancement in concrete confined by spirals
    (Department of Civil Engineering, University of Moratuwa, Sri Lanka., 2011-12) Kaneswaran, U; Reginthan, J; Perera, HMP; Baskaran, K; Ratnayake, N.
    The strength and ductility of the concrete Abstract: can be enhanced by confinement.lt can be achieved in many ways. Using spirals is one of the ways to enhance the strength by confinement. The confinement effect in concrete by spirals can be applicable to enhance the load carrying capacity of columns and shear carrying capacity of beams and flat slabs. This effect prevents structures from catastrophic failures during earthquakes. In this research study, experiments were conducted to determine the anchorage depth of the spiral, the shear enhancement in beams due to confinement by spirals and increment in failure load of flat slab panels a when spiral is used as a shear resistor. The actual shear carrying capacity and theoretical shear carrying capacity of the beams were checked using average integration method and discrete method.The experimental results indicated that the shear carrying capacity of the beam was enhanced by 35.7% for 30mm pitch spiral, 26.8% for 45mm pitch spiral and 16.1% for 60mm pitch spiral. The actual shear carrying capacity based on the experimental results matched closer to the value obtained by the average integration method. The failure load of the flat slab panel was increased by 12.3% when spiral was used as shear resistor.
  • Thumbnail Image
    item: Conference-Full-text
    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.
  • Thumbnail Image
    item: Conference-Full-text
    Study on rebound values on inclined planes
    (Department of Civil Engineering, University of Moratuwa, 2012) Baskaran, K; Liyanage, KLDO; Munasinghe, NT; Gunawardana, WWCJ; Nawagamuwa, U; de Silva, LIN
    Non-Destructive Testing (NDT) methods parameters like strength and durability of an existing structure. They offer significant advantages of speed, cost and lack of damage in comparison with test methods which require the removal of a sample. But they incorporate various limitations in practical use. This study is focused on the 'Rebound Hammer Test' which is used to assess the compressive strength by surface hardness. The rebound hammer concernedin this case, has been calibrated and charts have been developed to get the readings on vertical and horizontal surfaces only. When the structure to be investigated is consisted of an inclined surface, direct use of these charts may not be possible. During this study, basic formulation to calculate the corresponding horizontal rebound number to represent a rebound value obtained on an inclined plane was derived and verified. Taking readings on inclined surfaces of the cubes placed at different angles was done in order to observe the deviations and then the results were interpreted and analysed to obtain a suitable relationship by applying the derived formula.