Departmental Conferences

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item: Conference-Full-text
3D Environmental Force:Position Impedance Variation for Different Motion Parameters
(2015-08-03) Ruwanthika, RMM; Harsha, AM; Abeykoon, AMHS
The skill preservation of an expert has been a serious problem for countries with aging population because decrease of the number of successors. The concepts of haptic database and force sensor recorder which have been developed recently suggests solutions of using third multimedia type of haptic communication. Haptic information is a bilateral information of the law of action and reaction. The reaction from real world includes not only position and force information but also environmental impedance. In this paper, the behavior of environmental impedance has been studied with the changes of the different motion parameters like applied force, velocity, position and depth on the object 3D space. This idea is exemplified using a rubber balloon and a rubber sponge which is often modeled using simple linear equations. The experimental results show the importance of considering motion parameters when abstracting haptic information for a haptic database. Nonlinear impedance variations against the motion parameters suggest the necessity of adopting complex haptic abstraction techniques.
item: Conference-Abstract
Accounting of water footprint in substructure in a typical Multistory concrete building
Jain, H; Shrivastava, S
In last few decades, the building construction sector of India has become an important indicator of the development as it contributes a fair amount in GDP (gross domestic product) of nation. The fast growing construction consumes huge amount of natural resources such as, soil, water, woods, and by developing proper accounting method of consumption of these resources, the goal of sustainable construction can be achieved. This paper attempts to develop an empirical method of accounting of water footprint in construction of substructure (or foundation) in a multistorey concrete building. A substructure is the most important element of a multistorey building which connects it to the ground, and transfer loads from the structure to the ground. Water footprint attributed to substructure is the quantity of fresh water required for its various construction processes and supporting activities. The paper presents a case study on raft type, shallow substructures of three multistorey residential buildings of India to develop the method of accounting of water footprint. The results shows, total water footprint in construction of substructure in the case study buildings were accounted in the range of 7.71 – 36.10 litres per square meter of gross construction area. It also imputed from the results that water footprint consumption in concrete preparation has highest proportion, may be due to utilization of huge volume of concrete mix in construction of substructure. In addition, the paper also points out on some efficient reduction strategies of water footprint consumption to develop sustainable built environment.
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
ADOPTABILITY OF GREEN LEASE IN DEVELOPING COUNTRIES: THE CASE OF SRI LANKA
(2016-08-22) Hettige, NC; Perera, BAKS; Mallawaarachchi, H
The concept of Green Buildings is now being promoted as there is an increasing requirement for energy efficient buildings. With the boom of Green Buildings, Green Lease concept has become significant. However in Sri Lanka, presently Green Lease is not practiced very much. Nevertheless, attempts at adopting Green Lease cannot be ignored as there are clauses relevant to green buildings even in the existing lease agreements. Therefore, this research was carried out to investigate the adoptability of the Green Lease concept in Sri Lanka. Firstly, a literature synthesis was carried out to understand the Green Lease concept and its significance. Semi structured interviews and a documentary review were done thereafter to further identify the importance, and enablers and barriers of Green Lease. Subsequently, the findings were validated through expert interviews. The analysis revealed the significance of the Green Lease concept which provides a healthier work environment, lower utility charges and a good reputation for both the tenant and the landlord. However, there can be enablers and barriers of Green Lease. The contribution from the Green Building Council of Sri Lanka (GBCSL), the Government’s attempts to promote sustainable activities and conducting of business in Green Buildings are few of the enablers. Factors such as lack of policies and government rules, and poor awareness of the community about Green Lease are the significant barriers. The Government’s positive influence and the promotion of the Green Lease within the community will be beneficial towards adopting Green Lease. Several suggestions to minimize the identified barriers also have been made through the developmentof a framework.
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ADOPTING NET ZERO ENERGY BUILDING CONCEPT TO REDUCE ENERGY COST OF COMMERCIAL BUILDINGS IN SRI LANKA
(2016-08-24) Weerasinghe, I; Mallawaarachchi, H; De Silva, L
Fulfilling energy demand has become a major challenge faced by most of high rise buildings today as it creates high utility cost to the organization. Hence, most of the organisations, especially in commercial building sector seek better options to fulfil their energy demand as a major energy consumer among the other building facilities. Hence, several energy management practices have been introduced to enhance energy efficiency. In the governing concern on less energy and less environmental impact, Net Zero Energy Building concept has received attention. Net Zero Energy Buildings have a greatly reduced energy demand by an equivalent generation of energy from low-cost, locally available, non-polluting, renewable sources. However, the adaptation of this concept has become a major challenge due to various barriers. Therefore, the purpose of this research is to identify the barriers to adopt Net Zero Energy Building concept to commercial buildings in Sri Lanka for proposing probable solutions. As this research required a detailed investigation, case study approach was selected under qualitative phenomenon. Three cases were conducted in three selected commercial buildings to collect the data. Cross-case analysis technique was applied as the appropriate data analysis technique. Nvivo and Decision-Explore software’s are used to analyse and present the data. As the focal point of the research, barriers to adopt Net Zero Energy Building concept was determined relating to five major categories, such as, financial, legal, policy, social, and technical barriers. According to case study findings, this concept is more suitable for new building constructions than the existing buildings, as it is more effective to adopt it at the early stage of the building. Further, major barriers include limitations of organisational internal policies, preference of organisations for short term profits, unawareness and government rules and regulations. Accordingly, a framework is developed to propose probable solutions. The developed framework gives a value to the research, as it could use as a firm base in both organisational and national levels to adopt Net Zero Energy Building concept to reduce energy cost of commercial buildings in Sri Lanka.
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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.
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THE ADOPTION OF INTEGRATED PROJECT DELIVERY IN PUBLIC SECTOR PROJECTS IN NEW ZEALAND: THEWAY FORWARD
(2016-09-06) Naismith, N
The construction industry in New Zealand is responsible for around 40% natural resources, 30% energy consumption, and 30% greenhouse gases. The increased costs in natural resources, and energy, together with environmental concerns have pushed the demand for green buildings. Integrated Project Delivery (IPD) process has emerged as an enabler for green buildings. Successful IPD combines the partnering concept and lean thinking, it addresses the participant’s expectations, cuts costs, eliminates waste, reduces variability and generates value for all the participants. Yet many public sectors owners, do not have the authority to adopt features of IPD. However, owners can benefit from the IPD philosophy and features to take advantage of some key benefits. The purpose of paper is to examine the IPD tools and techniques appropriate for public sector organizations in New Zealand and to examine the barriers that public sectors organizations face in New Zealand while adopting those IPD features. A pilot study was conducted to examine these issues, semi structured interview were carried out with four public sector construction industry specialists. The interviews revealed that there is a gap between current and best practice in the New Zealand construction industry that is impacting on the adoption of IPD or IPD approaches. To improve the delivery of public sector projects a checklist of specific IPD tools and techniques appropriate for NZ public sector projects has been developed.
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THE ADOPTION OF INTEGRATED PROJECT DELIVERY IN PUBLIC SECTOR PROJECTS IN NEW ZEALAND: THEWAY FORWARD
(2016-09-06) Naismith, N; Tookey, J; Hoseini, AG; Kekreja, R
The construction industry in New Zealand is responsible for around 40% natural resources, 30% energy consumption, and 30% greenhouse gases. The increased costs in natural resources, and energy, together with environmental concerns have pushed the demand for green buildings. Integrated Project Delivery (IPD) process has emerged as an enabler for green buildings. Successful IPD combines the partnering concept and lean thinking, it addresses the participant’s expectations, cuts costs, eliminates waste, reduces variability and generates value for all the participants. Yet many public sectors owners, do not have the authority to adopt features of IPD. However, owners can benefit from the IPD philosophy and features to take advantage of some key benefits. The purpose of paper is to examine the IPD tools and techniques appropriate for public sector organizations in New Zealand and to examine the barriers that public sectors organizations face in New Zealand while adopting those IPD features. A pilot study was conducted to examine these issues, semi structured interview were carried out with four public sector construction industry specialists. The interviews revealed that there is a gap between current and best practice in the New Zealand construction industry that is impacting on the adoption of IPD or IPD approaches. To improve the delivery of public sector projects a checklist of specific IPD tools and techniques appropriate for NZ public sector projects has been developed.
item: Conference-Full-text
Adsorption of Cadmium and Lead Heavy metals by Chitosan Biopolymer: A Study on Equilibrium Isotherms and Kinetics
(2015-08-14) Unagolla, JM; SU, A
Since heavy metal pollution is a significant aspect to aquatic ecosystems, the objective of this research work was to investigate adsorption characteristics of chitosan as an alternative adsorbent material. In this study, chitosan, synthesized from locally available shrimp type “penaeus monodon” was used to observe adsorption characteristics of cadmium (Cd) and lead (Pb) heavy metals from aqueous solution. Batch kinetic experiment studies were conducted for changing initial pH, initial concentration of metal ions, particle size and degree of deacetylation (DD) of chitosan. Simplified models such as, pseudo first order, pseudo second order and intra-particle diffusion models were used to analyze the experimental data. The result showed that the adsorption capacity strongly depends on pH and DD. It was clearly seen that higher adsorption of heavy metals occur at comparatively high pH and high DD. Equilibrium experimental data were analyzed by using two different isotherm models namely, Langmuir and Freundlich. The characteristic parameters for each isotherm and related correlation coefficients were determined by using mathematical modeling software. Isotherms show that adsorption process of Cd and Pb is a heterogeneous process.
item: Conference-Abstract
Alternative foundation system for piles with soft toe condition
Chinthoory, G; De Silva, GTR; De Silva, A
This paper presents an alternative foundation system implemented for a 17 storied mixed development building at Kollupitiya. Initially, the foundation system of above building was designed to contain bored cast insitu piles driven to hard basement rock. During pile dynamic testing, the tested piles were found to undergo excessive settlements and failed to mobilize the expected design capacity due to soft toe condition. As an alternative for this problem, piled raft system was proposed and its feasibility was examined. Finite element modelling and analysis was carried out using SAFE v12 representing the raft as shell element and piles as springs. The simulation design and process is discussed in detail in this paper. The ‘conventional approach’ was highlighted in the design of raft with a load apportionment of 60:40 to piles and raft. While replacement of failed piles and rectification of piles incur significant time, cost and resources, the proposed piled raft system was found to be a sustainable and economical solution with least disturbance to the ground.
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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.
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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
Aperture-Array Directional Sensing using 2-D Beam Digital Filters with Doppler-Radar Front-Ends
(2015-08-03) Randeny, T; Madanayake, A; Sengupta, A; Li, Y; Li, C
A directional sensing algorithm is proposed employing doppler radar and low-complexity 2-D IIR spatially bandpass filters. The speed of the scatterer is determined by the frequency shift of the received signal following down-conversion. The downconversion is done by mixing it with the instantaneous transmitted signal. The direction of the scatterer is determined by the means of 2-D plane-wave spectral characteristics, using 2-D IIR beam filters. The proposed architecture was simulated for three scatterers at 10,o 30,o 60o from array broadside, traveling at speeds of 31 ms,−1 18 ms−1 and 27 ms−1, respectively. A doppler radar module was used to transmit and receive reflected signals, that has a carrier frequency of 2.4 GHz. Simulations show both direction and doppler information being enhanced.
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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.
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Appliance-Level Demand Identification Through Signature Analysis
(2015-08-03) Dhananjaya, WAK; Rathnayake, RMMR; Samarathunga, SCJ; Senanayake, CI; Wickramarachchi, N
Appliance specific load monitoring is very useful in energy management solutions that are becoming a challenging task with growing energy demand. It facilitates appliance recognition and load monitoring such that optimum resource utilization can be achieved by correct appliance scheduling. In this paper we present a study of non-intrusive load recognition using steady state appliance signatures for identifying commonly used household appliances. Current harmonics, active and reactive power components acquired from data loggers are used as appliance signature in this study. This analysis enables the capability of providing detailed information on appliances in use and consumers could benefit from customized energy management recommendations. Also, suppliers could implement smart metering technology introducing appliance level information as well. We propose algorithms for non-intrusive load recognition using combination of several methods and techniques. It was seen that a higher accuracy of identification could be achieved when a combination of techniques are used rather than using a single technique.
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APPLICABILITY OF GREEN HUMAN RESOURCEMANAGEMENT CONCEPT TO ACHIEVE SUSTAINABLE GOALS OF GREEN BUILDINGS IN SRI LANKA
(2016-08-24) Weerasinghe, RL; De Silva, L; Mallawaarachchi, H
Nowadays in world, construction of green building becomes a new trend. Many studies noticed that there are considerable amount of investments to the green buildings than conventional buildings. Since in last decade, the world has concerned about green building concept as one of the solutions to reduce environmental impacts. In achieving such foremost benefits of green buildings, human resource plays a vital role, especially to achieve sustainable goals of green buildings. Green Human Resource Management came into practice as a newest concept to create green responsive employees who make a significant contribution to environmental sustainability. However, Human Resource is not utilized in effective and efficient manner in most of the organizations. Therefore, the intention of this research is to investigate the applicability of Green Human Resource Management concept to achieve sustainable goals of green buildings in Sri Lanka. As this research required an in-depth investigation, the research problem was approached through three case studies which are conducted in three selected green buildings in Sri Lanka. Content and cross case analysis techniques are used to analyse the data. QSR. Nvivo software is used to simplify the data analysis. As key research findings derived through case analysis, in Sri Lanka, existing green buildings have not been implemented the proper Green Human Resource Management process. Hence, the gaps in existing Human Resource Management process in green buildings are identified in relation to the job analysis, recruitment, selection, induction, training and development, performance evaluation and discipline management. Improper job designing, not including green competencies, use of traditional Human Resource Management process, unawareness, no proper performance evaluation criteria are identified as major gaps in Human Resource Management process in green buildings. Accordingly, a framework is developed to propose various strategies to fill the gaps in existing process to effectively utilize the Human Resource for achieving sustainable goals of green buildings in Sri Lanka as the main implication of this research
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Application of a process-based, distributed, hydrological and material transport model to assess water resources and pollute transport in malwathu oya basin, sri lanka
Dahanayake, AC; Rajapakse, RLHL
The Water and Energy transfer Processes Model – WEP Model is a distributed, physically based hydrologic model that has been coupled with a material transport component. The model uses meteorological, geographical, hydrological data and, data relevant to anthropogenic activities and water quality simulation processes, as inputs. The model is capable of providing time series values of water and heat balance as well as water quality/material transport results for each grid, as outputs. It has been successfully applied to river basins in Japan, China, Korea and elsewhere to study the water resources management options and pollution caused by dissolved and particulate pollutants including the dispersal of excess Nitrogen and Phosphorous introduced by industrial effluents and chemical fertilizers. The present study incorporates a detailed modelling approach to the Nachchaduwa sub-catchment (598.74 km2) of the Malwathu Oya river basin, to study the water resources management options under the effect of varying rainfall patterns and impending climate change impacts. The model can be extended to study the fate and behaviour of the elements (Nitrogen and Phosphorous) which are added to the waterways as a result of the extensive use of agrochemicals in paddy lands in the upstream catchment area. This paper reviews the current state of the catchment as well as the suitability of applying the proposed model to Sri Lanka to assess this basin, which is seasonally stressed due mainly to over exploitation and water pollution. Apart from the water resources management, a quantitative analysis on the fate of excess amounts of agrochemicals used can also be concluded by studying the dispersal and accumulation behaviour of these elements after they have been added to the crop fields and waterways. The findings of the research study will be useful in identifying possible better water management scenarios and managing the fertilizer/agrochemical usage of this catchment in a more pragmatic manner. This study will set the baseline for commencing and continuing quantitative studies regarding studying the behaviour of the pollutants including their conveyance and spatial and temporal accumulation patterns after they have been added to the waterways, in the North Central Province of Sri Lanka
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Application of lean concepts in the construction industry
Madushan, STK; Hathurusinghe, HDDC; Dissanayake, PBG
Sri Lanka is a developing country experiencing a huge construction boom. All construction use various types of resources and waste of resources occur at all construction sites. These wastes include not only material resources but also labour, equipment, time, space, etc. The basic idea of lean is to create more value for the customer with fewer resources. Lean construction projects are easier to manage, safer, complete sooner and cost less and the end product is of better quality. The aim of this study is to understand the level of awareness on lean concepts in the construction industry of Sri Lanka, identify the wastes and classify using lean concept, identify barriers and difficulties that may be encountered in the implementation of lean concepts and propose effective and efficient means of lean construction management techniques to be adopted by the Sri Lankan construction industry.
item: Conference-Abstract
Application of meta-modeling based finite element solution conversion method to develop smart initial guess of conjugate gradient method for solid element simulation
Jayasinghe, JASC; Bandara, CS; Riaz, MR; Abeykoon, D
Smart initial guess of Conjugate Gradient (CG) method for solid finite element simulation is developed by using the meta-modeling based finite element solution conversion method. The key feature of this solution conversion method is the rigorousness; the meta-modeling ensures that the most appropriate structural or solid element solution is the one that is close to the solid or structural element solution, respectively, since an error between structural and solid element solutions is accurately defined in a solution space of continuum mechanics. The initial guess of CG method of this study is developed by using an approximate solid element solution which is converted from a relevant structural element solution. Two numerical examples; a cantilever beam and frame problems, of the proposed CG method are presented. The results show that the computational cost is significantly reduced in the proposed CG method as compared to the ordinary CG method. There is an expectation that this reduction of computational cost of solid element simulation will become more significant with the size of the problem targeted.
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Application of post tensions in high rise building construction in sri lanka
De Silva, SHMAPK; Sudhira De Silva; Disanayake, PBR
The world is changing; the economy is changing; and Architectural practice is changing. Therefore, there is a definite trend towards the irregular shapes with large spans in buildings due to the fact that there is now more emphasis on providing large uninterrupted floor space which can result in higher rental returns. Today the building industry is taking the next step in concrete technologies by introducing post-tension systems to slab construction with the use of system formwork and high strength concrete. Post-tensioned concrete has proven to be a preferred method of construction for commercial and office buildings, residential apartments, high-rise condominiums, parking structures, and mixed-use facilities such as hotels and entertainments. The main benefits over conventionally reinforced concrete being its ability to span greater distances without resorting to thick slabs and beams (and the consequent loss of head height), reduce deflection and cracking, Reduction in overall building mass, which is important in zones of high seismicity and superior performance of diaphragm action at building irregularities. There are also some associated labour and time savings. The objective of this paper is to introduce the post tension slab system to Sri Lankan construction industry. This study will discuss the benefits of having post tension in building industry, challengers encounter in PT designs and quality controlling process during construction