Departmental Conferences

Permanent URI for this collectionhttp://192.248.9.226/handle/123/10024

Access to full-text papers of this collection is allowed only within the University premises (IP based access).

Browse

Now showing 1 - 20 of 98

item: Conference-Full-text
ACI guidelines to assess the performance of CFRP-strengthened concrete beams with transverse end U wraps
(2016-01-06) Ariyachandra, MREF; Gamage, JCPH
In this comprehensive study, firstly, the theoretical model described in ACI 440 committee report to calculate the area of transverse U wraps provided for anchored CFRP-strengthened concrete beams was examined. Then, an experimental study was carried out with a total of 10 small-scale test specimens and test parameters were set to inspect the validity of the limitations given in the above theoretical model. Theoretical calculations were performed in accordance with ACI guidelines for the above test specimens as well as for the previous research studies. Finally, the constraints of applicability of the theoretical model given in ACI 440 committee report was discussed presenting new recommendations for different scenarios.
item: Conference-Full-text
Adoption and Scope of Building Information Modelling (BIM) in Construction Industry of Pakistan
(2016-01-05) Fatima, A; Saleem, M; Alamgir, S
Building Information Modelling “BIM” is becoming a better known established collaboration process in the construction industry. Owners are increasingly requiring BIM services from construction managers all over the world, but the adoption of BIM in building construction industry of Pakistan is very slow. Globally one of the great advantages of BIM is the ability to create an accurate model that is useful throughout the entire life of the building, from initial design through occupancy and operations. The benefits of BIM are evident in its capability. There are two objective of this research work, first to identify the problems faced in construction management and secondly to identify the barriers in adoption and implementation of BIM in local building construction industry. The research objectives were achieved through literature review, case studies, and questionnaire. First, the research identified the uses of Building Information Modelling for construction industry, and then identified the problems faced by construction managers in construction management. On the basis of literature review a questionnaire was prepared and surveyed to identify the source of construction management problems in the building construction industry of Pakistan. Then, the project examined the uses and benefits of BIM in the construction of a research facility by minimizing the sources of many identified problems in questionnaire survey. Finally, the project concluded and recommended the ways to increase the use of BIM in building construction industry of Pakistan.
item: Conference-Full-text
Analysis of Factors Contributing Civil Engineering Project Delays in Sri Lanka
(2016-01-05) Kesavan, M; Gobidan, NN; Dissanayake, PBG
A construction project is commonly acknowledged as a successful project when the aim of the project is achieved in terms of predetermined objectives of completing the project on time, within budget and to the required quality standard. Delay in the completion of a construction project can be a major problem for contractors, consultants as well as for clients. These delays lead to costly disputes and adverse relationships amongst project participants. Projects can be delayed due to large number of reasons. The reasons are related to various types of uncertainties associated with activities during the construction process or during the planning and design stages. Therefore a comprehensive survey was carried out to identify the critical factors that cause the delays in Sri Lankan construction projects. From in-depth literature studies, 52 causes of delay were identified. Questionnaire survey was carried out among 107 selected construction projects in Sri Lanka. The findings show that the delay in Sri Lankan construction projects is mostly originated by labour, followed by contractor and client, while external related causes are less important. This paper also explores and provides some recommendations to reduce the impact of delays on civil engineering projects in Sri Lanka.
item: Conference-Full-text
Analysis of Strain Rate Dependent Tensile Behaviour of Polyurethanes
(2016-01-06) Somarathna, HMCC; Raman, SN; Badri, KH; Mutalib, AA
The stress-strain behaviour of elastomeric polymers, such as polyurethane (PU), exhibit high rate dependency, stress–strain non-linearity, and high pressure dependency when compared to other construction materials. Since these polymers exhibit the potential to be applied as retrofitting and protective material for various types of structural materials, in enhancing their load-carrying capacity, ductility and structural survivability under different loading regimes, it is essential to comprehensively investigate their mechanical behaviour at varying strain rates. This study was undertaken to investigate the tensile stress-strain characteristics of elastomeric PU at varying strain rates, ranging from 0.001 s-1 to 0.1 s-1 (low to intermediate). The primary emphasis of this study was on the strain rate sensitivity of the tensile properties, including the Young’s modulus, tangent modulus, ultimate tensile stress, fracture strain, and strain energy modulus. The findings indicated that stress-strain behaviour of the PU exhibited high dependence to variations in strain rates and stress–strain non-linearity. The behaviour of PU also provided good concurrence with recent studies, which explored the strain rate dependency of other elastomeric polymers.
item: Conference-Full-text
APPICATIONS OF ENVIRONMENTALLY FRIENDLY CELLULAR CONCRETE IN CONSTRUCTION
(2016-01-06) Purasinghe, R; Shimose, F; Lum, H; Shamma, J; fire resistance; green roofs; pipeline backfill; thermal insulation; tunnel annular space backfill.
Cellular concrete is a cost effective construction material that is continuously gaining traction and popularity in the US and elsewhere. Cellular concrete is a material consisting of Portland cement, water, and foam. When it hardens, the concrete has an oven-dry density ranging from approximately 50 lbs/cubic feet to 90 lbs/cubic feet. Some applications have achieved an even lower density that 50 lbs/cubic feet. Recipes may also include aggregates such as fly ash. Admixtures are used as well depending on the final use of the product. Cellular concrete has numerous applications in the building construction industry and as an underground backfilling material, but lately other uses in the infrastructure field have been gaining popularity especially as a stabilizer around transmission conduits. Popular application of cellular concrete includes insulation, fire retarding, and sound proofing for a variety of structures. Cellular concrete systems provide better drainage, increased fire resistance, increased wind uplift ratings, improved seismic values, efficient thermal insulation, and improved sound attenuation in an environmentally friendly manner. In underground applications, cellular concrete is used as a cost effective filler material in lieu of soil without the compaction effort required when using soil. Most recently the infrastructure field introduced cellular concrete as a backfill and filler material around underground structures such as segmental tunnel liners and pipelines. Cellular concrete can be used as backfill material at pipeline fault crossing by allowing localized ground deformation without overstressing the pipe section. This application can minimize damage to the pipeline or tunnel transmission structure that results from a shear failure of the pipe. However, the low compressive strength of cellular concrete limits its application as a structural material. The paper discusses material behavior and characteristics, state of the art construction methods, and advantages and disadvantages of using cellular concrete as a construction material in current times.
item: Conference-Full-text
Application of Water Quality Simulation for Water Safety Plan at Mahaweli River Basin, Kandy
(2016-01-04) Matsubara, K; Tobe, T; Murata, M; adachi, R; Ishikura, S; Wada, Y; Weragoda, S; Ramawickrama, U; Jinadasa, S
Water Safety Plan (WSP) is an effective risk assessment framework to elaborate possible risks for water supply systems. However, risk quantification of “severity” and “likelihood” of specific incidents is challenging especially for the risks at water sources. Water quality simulation is an essential tool for predicting the risks and applying effective countermeasures, while data availability and usability for practitioners remains as obstacles for implementation. The objective of this study is to develop appropriate simulation methodology for the risks at water source of all the water supply systems in Sri Lanka. In this report, we focused on the Mahaweli river basin in Kandy. Reviewing the existing WSP at Greater Kandy WTP, the contamination of intake water by the leachate from neighbouring solid waste damping site was considered as a significant risk. We developed dynamic hydraulic model and water quality model which can configure input and output data on Microsoft Excel interface. As a result of the simulation, it was implied that the contaminant from the leachate can flow back to the intake of the WTP due to density flow. Re-risk assessment for possible countermeasures showed the structure modification and leachate treatment are effective to mitigate the risk for water quality hazards.
item: Conference-Full-text
Apportionment and Ranking of Risk Elements in Construction Industry of Sri Lanka-Contractors’ Perspective
(2016-01-05) Dolage, DAR; Wijesekara, ALUP
This study provides the results of a survey of major contractors engaged in the Sri Lankan construction industry. It is aimed at identifying common risk elements affecting construction industry projects, determining how they are apportioned between the owner and the contractor, and quantifying and ranking their significance. The previous studies provided a list of 52 risk elements and with the help of a pilot study it was reduced to manageable 25 risk elements having a great relevance to the Sri Lankan construction industry. Altogether 72 respondents selected from among major contractors in Sri Lanka (C1 to C4) were involved in the questionnaire survey of the study. The analysis of the results show that only some risk elements are apportioned more to one party (apportionment of at least 65%) either contractor or owner. Shortage of labor, materials, tools and equipment (82%), Low productivity of labor and equipment due to complexity of work (78%), Labor disputes & trade union action (76%), Delays due to sub-contractors, suppliers and other bodies (74%), Difficulty to coordinate with sub- contractors (74%), Corruption (70%), Delayed payment by owner (68%), and Accidents (66%) are apportioned more to contractors whereas, Delay in approvals and permits (70%), is apportioned more to the owner than to the contractor. The risk elements were ranked according to their significance and the most significant risk elements are, in descending order of significance are; Shortage of labor, materials, tools and equipment, inaccurate and incomplete design, Financial failure resulting from owner and contractor, Substandard quality of work. The results indicate that contractors perceive that risks are apportioned disproportionately more towards them. The implication of this is that naturally contractors tend to quote higher bid prices to cover their potential risks.
item: Conference-Full-text
ASSESSMENT ON DEFECTS OCCURENCE AND REWORK COSTS IN HOUSING CONSTRUCTION SECTOR IN SRI LANKA
(2016-01-05) Dahanayake, BMY; Ramachandra, T
Defects in building construction are considered to be one of the recurring problems in the construction industry. It has adverse effects on project performance, building performance, and client or end-user satisfaction. The lack of focus on defects leads to negative impacts on cost, duration and resources of projects. Defects may generate controversies among parties involved, not only affecting ongoing construction but also during its operation. Rework cost is another effect of defects, absorbs a significant share ranging from 0.5% to 3.7% of total project costs. This research therefore investigates the most frequent defects and rework cost involved in rectifying the defects in residential buildings in Sri Lanka. A questionnaire survey and subsequent interviews to be carried out together with a detailed analysis of documents will be employed to address research focus. 47 housing projects which exposed to defects were studied. Findings of the study indicates that defects such as bulging of columns, beams and slabs, verticality issues of masonry walls, cracks in plastering and painting, defects in doors and windows are more likely to occur in residential buildings in Sri Lanka. The mean total rework cost as a percentage of the cumulative work done value was found to be 0.92%. For a mean total rework cost of 0.92%, the likelihood that a project exceeds is 37%. Finally, the study proposes strategies such as proper documentation, proper coordination of works and uplift the attitude towards reporting the defects of lower level staff would help practitioners to minimise the defects in building construction in Sri Lanka.
item: Conference-Full-text
Atterberg Limits Estimation of Pilani Soil Using Ultrasonics
(2016-01-06) Kumar, K
Depending on water content, four physical states of soil consistency are used. The water contents at which soil undergoes physical state change are called Atterberg limits. Liquid as well as plastic limit are two commonly used Atterberg limits and are used extensively, either individually or together, with other soil properties to correlate with engineering behavior such as compressibility, compactibility, shrink-swell and shear strength. Conventional method of liquid limit determination requires test to be conducted at 5 (at least) different water contents for accurate estimation. Even liquid limit estimation using cone penetrometer requires experiment to be carried out at more than one water content. Same is applicable for plastic limit estimation. Sand content has effect on its liquid and plastic limit, as well as pulse velocity through it. Consequently, it should be possible to estimate liquid and plastic limit by knowing pulse velocity through it. Pulse velocity using through transmission technique (at constant water content and density); as well as their liquid and plastic limits using conventional techniques at varying sand content were determined and plotted for Pilani soil. This plot can be used as calibration curve for aforementioned estimation purposes and can be developed for other region soils as well.
item: Conference-Full-text
Base Course Geocell Reinforcement Evaluation by comparing 3-D FEM and Laboratory Evaluation
(2016-01-06) Inti, S; Sharma, M; Tirado, C; Tandon, V
The shortage of high-grade base material and emphasis on using recycling base material has led to use of geocells reinforced bases in the past decade. The geocells provide reinforcement by confining base material and have been used for increasing bearing capacity of supporting soil, reducing settlements, using inferior quality material, reducing thickness of base layers, etc. It can be an economical option in rehabilitation of pavements and construction of low volume roads. Various studies have been conducted to evaluate the behaviour of geocell reinforced layers using expensive and time intensive laboratory tests. The working principle of geocell reinforced layers using various pavement materials, loading types, geocell types etc., can be comprehended quickly and economically using Finite Element Modelling (FEM). In this study, various significant FEM model parameters like constitutive material models and contact models were examined. The results were compared with the laboratory test results and specific contact and constitutive material models that predict behaviour similar to the laboratory results were recommended.
item: Conference-Full-text
Behaviour of Concrete Produced with Cement and Rice Husk Ash
(2016-01-05) Abdullah, MA; Gamage, JCPH
Disposal of rice husk and its ash has been identified as a major problem in areas where rice production is abundance. Cement is an expensive material which plays a major role in the construction industry. This study shows the utilization of Rice Husk Ash (RHA) in concrete by conducting the laboratory experiments. Replacement of cement with RHA enhances both compressive and tensile properties of concrete. For this study, RHA was obtained from Bio-Energy power plant located in Ampara, Sri Lanka. As received RHA was sieved in order to prepare two types of samples with different particle sizes. Enhanced performances of Ordinary Portland Cement (OPC) can be achieved with 10% replacement of OPC by RHA regardless of particle sizes. Moreover, the adverse environmental impacts associated with RHA can also be reduced by utilizing the RHA in cementitious systems
item: Conference-Full-text
BIM Software Framework for Prefabricated Construction: Case Study Demonstrating BIM Implementation on a Modular House
(2016-01-05) Samarasinghe, T; Mendis, P; Ngo, T; Fernando, WJBS
Building information modeling and prefabrication are concepts that are undergoing intense study in the construction industry. As the technology to implement BIM is commercially available, many industries have started to use BIM in construction related projects. However, BIM implementation can vary significantly according to the nature of the project. Therefore, development of a BIM software framework for a particular industry to meet its requirements is the most efficient way to use Building Information Modeling. This paper will present a BIM software framework developed for prefabricated construction industry and will demonstrate the use of the framework during the design stage of a modular pre-fab house.
item: Conference-Full-text
BOND STRENGTH BEHAVIOR OF HEADED REINFORCEMENT BAR WITH VARYING EMBEDMENT LENGTH
(2015-12-29) Gond, S; Kulkarni, SM
Abstract: Headed reinforcement is a relatively new product and has not been used in many applications. Headed reinforcing bars have been extensively used in the construction of offshore oil platforms where hooked bars have traditionally been used to anchor longitudinal reinforcement or bars bent for ties and transverse reinforcement. Hooks and bent-bar ties create a large amount of congestion in the reinforcing cage which leads to difficulties during construction. Using headed reinforcement removes the tail extensions of hooks and allows fewer larger bars to be used, greatly reducing the congestion of the reinforcing cage. It has been found that the use of headed reinforcement can greatly decrease the time needed to erect the reinforcement resulting in large cost savings. Headed reinforcement has also been used in a few projects for strengthening and repairing footings of highway structures. A total 81 Pullout test were performed to the study of Bond behavior of Headed reinforcement bar in concrete with different Embedment length with various diameters of bars, various grade of concrete and various sizes of cubes. In this research project, it is proposed to execute experimental work by using headed reinforcement bars. The effect of different parameters like embedment length, head shapes and concrete grades, threaded headed reinforcement bars can be study. The results will be used to develop design recommendations for the application of headed reinforcement bars.
item: Conference-Full-text
Broken Wave Loads on a Vertical Wall: Large Scale Experimental Investigations
(2016-01-04) Ramachandran, K
Many storm protecting structures (eg. seawalls) are increasingly built at the back of the beach such that breaking waves are unlikely to reach them during the normal sea state. These structures are predominantly subjected to broken waves under most severe storm and tide conditions. Detailed studies relating broken wave forces to the incident wave parameters and beach slope are lacking. Therefore simplified assumptions are used to estimate the design loads due to broken waves. This knowledge gap has motivated to investigate the broken wave impact loads on coastal structures. A series of physical model experiments were carried out in the Large Wave Flume (GWK, Hannover, Germany) in order to measure the broken wave impact loads on a vertical wall. This paper describes the experimental results in detail. Based on the measured forces, a simple empirical formula is derived in terms of the wave parameters.
item: Conference-Full-text
Building Information Modelling Implementation in Practice: Lessons learned from a housing project in the Netherlands
(2016-01-05) Aibinu, AA
Real-world implementations of BIM can serve as use cases to demonstrate BIM implementation strategy in practice. This paper presents the findings from a case study of BIM implementation on a housing project in the Netherlands. It describes how BIM approach was used to facilitate the delivery of the project. The benefits and challenges encountered are discussed. The role of BIM process management, BIM activities and key enabling technologies are examined as well as the impact of procurement on BIM implementation. The paper highlights how BIM activities was structured to deliver the project faster (time), cheaper (cost) and better (quality and performance). The analysis is based on project documents and interview with those involved in managing the BIM process. One of the major implications of the findings is that: BIM implementation is a set of interrelated activities and processes. Organisations seeking to work using BIM approach need to actively engage with the process and, in an ongoing basis, learn from their experiences as well as improve based on the lessons learned.
item: Conference-Full-text
Catchment Protection of Gin Ganga (River) as part of Water Safety Plan (WSP) in Greater Galle Water Supply Scheme (GGWSS)
(2016-01-04) Wijesiri, ID; Chaminda, GGT; Silva, GHAC
Gin Ganga (River) is the main raw water source to Greater Galle water Supply Scheme (GGWSS). Managing drinking water quality from catchment to consumer is the main objective of the Water Safety Plan (WSP) of GGWSS. There are three Water Treatment Plants (WTP) purifying and delivering 80,000m³ of treated water per day to approximately 450,000 people through 15 distributions centers. The Gin River has a total length of 113km and a catchment area of about 932 km² Catchment of the Gin River includes Galle, Matara, Ratnapura and Kalutara administrative districts. The Gin River originates from the Gongala mountains in Deniyaya and flows to the Indian Ocean at Gintota in Galle. Gin River annually discharges about 1268 million m³ of water to the sea. Rainfall pattern in the catchment is bimodal, falling between May and September and again between November and February. Rapid changing of land use pattern and high rate of application of agrochemicals and fertilizers has significantly affected the raw water quality. A quantitative and continuous assessment of water quality along Gin River is necessary to identify the trends and to develop sustainable remedial actions. Content of heavy metals in raw water is also an important parameter to be tested due to lack of previous data. The WSP Team is already established and the Greater Galle WSS WSP has been completed. The External Stakeholder Team consists of relevant stakeholders; the Galle District Secretary, relevant Divisional Secretaries, Health Authorities, Irrigation Officials, Agriculture Officials, Central Environmental Authority etc. The initiatives and the encouragement of the External Stakeholder Team to implement the catchment protection program for Gin River is commendable as the group has already carried out a Sanitary Survey and pollution source identification exercise along the Gin River. The objective of this paper is to present the Water Quality Modeling System prepared for Gin River and its effectiveness in protecting the catchment to effectively implement the Greater Galle WSS Water Safety Plan.
item: Conference-Full-text
The Challenges and Obstacles of Post-Disaster Road Infrastructure Reconstruction in the Pre-Construction Phase
(2016-01-05) Hayat, E; Amaratunga, D; Haigh, R
Purpose-The reconstruction of road infrastructure in the post-disaster context require different approach when compared with road projects in the normal development context. Disaster recovery projects are seen as having their own unique identity, particularly due to stakeholder issues, resource challenges, capability issues, and even long-term reliability concerns. This paper invites a discussion regarding the challenges and obstacles identified in the reconstruction of road infrastructure in a post-disaster reconstruction setting, and focuses the discussion on the pre-construction phase. Design/ Methodology/ Approach - The challenges and obstacles presented in this paper are based on the literature and the empirical evidence collected from the research in three case study districts in Aceh, Indonesia. Twenty-eight face-to-face semi-structured interviews were conducted with stakeholders of road infrastructure at the local, provincial and national level, and represented by respondents from the public works, planning agency, disaster management agency, consultant, contractors, and donor agencies. The findings were triangulated with the literature and consulted with five experts in the road infrastructure and disaster reconstruction area. Findings - The identified challenges and obstacles are divided into three groups of discussion; planning and programming, road design, and procurement. Whilst some of these challenges are not unique to post-disaster context, the scale of the risks had been undermined. Originality/ value - This paper identifies the challenges and obstacles of a road project in the post-disaster setting from the pre-construction perspective. Identification of these challenges and obstacles may help improve the implementation of post-disaster road infrastructure reconstruction projects in future recovery projects, particularly in the developing world.
item: Conference-Full-text
CLIMATE CHANGE IMPACT PREDICTION IN UPPER MAHAWELI BASIN
(2016-01-04) Herath, HMVV; Dayananda, RGAB; Weerakoon, SB
Upper Mahaweli basin is the origination of the main water source of Sri Lanka which is the Mahaweli River. Therefore it is a timely requirement to identify the future climate trends on the basin, to take suitable adaptation strategies. Statistical Downscaling model (SDSM) was used to predict future rainfall patterns of the study area. Observed point rainfall data of ten gauging stations within the study area and Global Climate Model (GCM) data of Hadley Centre Coupled Model, Version 3 (HadCM3) were used for model calibration and validation processes. A representative data set for the study area was generated using Thiessen polygon method from the observed rainfall data of selected gauging stations. Quality of the input data was checked prior to the model calibration. Daily rainfall was forecasted from 1961 to 2099 under A2 (high emission scenario) & B2 (low emission scenario) defined by Intergovernmental Panel on Climate Change (IPCC). Under A2 scenario the total annual rainfall, maximum annual rainfall and annual averaged daily rainfall show an increasing trends and under B2 scenario all the above mentioned parameters show decreasing trends. But the recorded decreasing trends are insignificant.
item: Conference-Full-text
Clustering Techniques and Artificial Neural Network for Acoustic Emission Data Analysis
(2015-12-29) Attanayake, UB; Aktan, HM; Mejia, J; Hay, R
Abstract: Acoustic emission (AE) sensor technology is commonly used for real-time monitoring of fatigue sensitive details. This is mainly due to its ability to detect fatigue events (crack initiation and opening) by mounting sensors in the vicinity of potential crack location. Also, AE data can be used for damage location detection. Even though AE provides many capabilities with regard to fatigue monitoring, many implementation challenges exist. A majority of the challenges is associated with noise elimination, AE signal analysis, and interpretation of the results. This article describes AE implementation for monitoring a fatigue-sensitive detail and use of data analysis techniques such as cluster analysis, non-linear mapping (NLM), and three-class classifiers to identify the relationship of each cluster to the characteristics of crack opening signals, background noise, and structural resonance.
item: Conference-Full-text
COMPARISON OF DESIGN METHODS OF WATER RETAINING STRUCTUERES USING THE PROVISONS OF INTERNATIONAL CODES
(2015-12-29) Ahamed, MAA; Madushanka, PNM
Abstract: Durability and impermeability in a water-retaining structure are of prime importance if the structure is to fulfill its function over its design life. In addition, serviceability cracking tends to govern the design of water retaining structures. This research concentrates on load-induced cracking specifically that due to pure bending and to direct tension in water retaining structures. At present Sri-Lankan designers tend to use British standards in the design of water retaining structures. But today the countries in the world have adopted different codes with the belief that the code adopted will best fulfill the requirements in designing water retaining structures for their particular exposure. Even with the proper design using that selected code, a question arises about the acceptability of the design with regard to other international codes. Thus, Comparison of these international codes is of paramount importance. ACI 350M, AS 3735, BS 8007 and EN 1992-3 were the codes that were selected to do the comparison. Identifying the major contributors for cracking as flexure and direct tension load case according to the given procedure for each code to control cracking spreadsheets were developed. During the project several parameters were varied and by analyzing the obtained results, an effort was taken to evaluate the design approaches given in each code to control cracking.