Buildings consume a large portion of global energy, and the decisions taken during the early design stage in terms of material selection, supplier selection (transportation impact) and construction method adopted dictate the sustainability performance of the complete life cycle of the final building product. Therefore, this study focuses on the quantification of energy impact as well as providing guidance for mitigating this energy consumption using Building Information Model (BIM) by realizing the building in the virtual environment and linking Life Cycle Analysis (LCA) methodology to the BIM environment. BIM is the industry standard for delivering building projects and by enabling BIM environment to perform LCA, this study provides seamless and efficient platform for incorporating sustainability practices in the main stream construction business. The scope of the study is limited to A1-A3 (Cradle to Gate) and A4-A5 (Transportation and Construction Phase) of the European standard EN 15978. The outcome of the study is in the form of a framework implemented by an Application Programming Interface (API) built for a well-known BIM authoring tool. The framework is validated through a case study and the results are presented in a number of publications listed below.
Light train transportation is essential for the whole infrastructure system. It might be helpful to apply a multi-agent system to help in optimising resource allocation and solving spatial and temporal conflicts. Several objectives will be achieved at the end of this research. Firstly, a methodology of an intelligent agent system for real-time simulation of the light train network will be proposed. Secondly, algorithms for optimising energy distribution based on energy consumption analysis of the network will be developed. Negotiation rules will be developed and applied to the agent group for better communication inside the network. Thirdly, operational strategies for individual train operators based on automated machine guidance (AAMG) will be explored, so as to minimise the disadvantage of manual operations.
PhD Project: Characterization of Artificial Aggregate from Solid Waste
Abstract:Increasing solid waste from different sources has caused massive environmental and depositary problems and on the other hand the exploitative use of natural resources for the use of aggregates in concrete and other works has caused depletion of the limited resources. This research aims to use the solid waste from different source as a raw material to produce artificial aggregates minimizing the use of natural aggregates and reducing problems that arises from the deposition and environmental problem. The research proposes the use of Nano-particles in the production of the artificial aggregates for enhanced mechanical properties. This research also focuses on the various characterization techniques used for the characterization of the artificial aggregates. The research expect to develop artificial aggregates with nanoparticles that has enhanced properties and can be extensively used as an alternative or to partially replace the use of Natural Aggregate.
PhD Project: Semantic-enhanced 3D reconstruction of building information models
Abstract:Timely and accurate monitoring of onsite construction operations can bring an immediate awareness on project specific issues. Despite their importance, the current practices are still time-consuming, costly, and prone to errors. To facilitate the process of collecting and analyzing performance data, researchers have focused on methods that can automatically assess ongoing operations. A major line of work has particularly focused on developing computer vision techniques that can leverage still images, time-lapse photos and video streams for documenting the work in progress and re-construct a geometric model of the construction site. However, extra semantic data have to be integrated into building information models (BIM) manually with the traditional approach. This project proposes an innovative method to enable semantic-rich information modelling by using computer vision and artificial intelligence technologies, so as to greatly improve the degree of automation in construction site management.
PhD Project: Road surface defects detection and classification using big data analysis and artificial intelligence
Abstract:The detection of damage in infrastructure automatically is the trend in civil engineering field to prevent the severe collapse of infrastructure. Pavement damage information has to be collected and it can help to do the maintenance of pavement immediately, as pavement damage can often result in driving discomfort and cause traffic accidents and traffic jams. Pavement damage monitoring system is proposed based on the time-frequency analysis and the convolution neural network. Acceleration sensor and mobile phone installed in the acquisition vehicle collect response of vibration between the wheel and the road, including pavement damage, maintenance hole, and normal pavement. Due to the original vibration signal contains the only one-dimensional domain (time-acceleration), using time-frequency analysis including Short-Time Fourier Transform and Wavelet Transform can transfer a one-dimensional vibration signal into two-dimensional time-frequency energy spectrum matrix, further combining with CNN model (STFT - CNN and WT – CNN) can detect pavement damage automatically. The energy spectrum matrix obtained from STFT and WT can effectively obtain different signal characteristics in terms of time and frequency characteristics.
Nationality: Sri Lanka
PhD Project: Repair and strengthening of corroded RC columns using organic corrosion inhibitors and Textile Reinforced Mortar (TRM)
Abstract:The need for upgrading Reinforced Concrete (RC) structures, especially for those having high importance to society, has increased significantly due to public safety and maintenance cost issues. The use of Textile Reinforced Mortars (TRM) to retrofit, RC elements have emerged as a promising alternative to the use of Fibre Reinforced Polymers (FRP), mainly because of TRM's improved performance at elevated or low temperatures, on wet surfaces, at aggressive environments, but most importantly their sustainability. At the same time, organic corrosion inhibitors such as small-molecule-based alcohol amine series are becoming the focus of attention due to their environmental-friendly behaviour. This study investigates the repairing and/or strengthening of large-scale concrete columns suffering from corrosion problems with the use of different types of corrosion inhibitor incorporated patch repair mortars and TRM.
PhD Project: Lattice-Boltzmann studies on the effect of the morphological properties of porous media in immiscible displacements
Abstract:The understanding of immiscible two-phase flows in porous media is of critical importance in numerous industrial operations such as, enhanced oil recovery, geologic CO 2 sequestration, groundwater supply and remediation, catalytic processing in fixed bed reactors etc. The physical properties of the displaced immiscible fluid phases, such as density and viscosity ratios, fluid phase wettability, as well as flow conditions, such as driving forces, initial phase saturations etc., are only some of the factors that affect the relative fluid flow within porous media. However, it has been demonstrated that morphologically different porous media will result in different flow patterns during immiscible displacements, such as drainage and imbibition. The proposed study aims to investigate the impact of the morphological properties of 2-dimensional and 3-dimensional porous structures, characterized by Minkowski functionals, in immiscible displacements, through the application of a high density ratio multi-relaxation time lattice-Boltzmann model.
PhD Project: Flood Frequency Analysis in A Non-Stationary Environment
Abstract:Flood is one of the most common and significant natural disasters in the world. Over recent decades, accelerated population growth and changes in land-use patterns have resulted in increased human vulnerability to floods. Meanwhile, climate change may also increase the frequency and magnitude of flooding. Flood frequency analysis is always a cornerstone for flood risk control, hydraulic structures design and water resources management. However, the conventional flood frequency analysis is based on stationary assumption. Due to climate change and human intervention in river basins, the stationary assumption for flood frequency analysis has faced more and more challenges currently. It may result in underestimation of flood quantiles and increase the risk of failure of engineering structures. Therefore, taking non-stationarity into account may be crucial for human adaptation to the changing environment. This study focuses on nonstationary flood frequency analysis aiming to provide new insight into flood-generating mechanisms for improving the flood estimation under the changing environment.
PhD Project: DEM simulations of triaxial behavior of structural concrete
Abstract:The response of concrete at a material level is characterised by a distinctly non-linear stress-strain behavior. Such a characteristic is already evident in the early portion of the stress–strain relations, becoming more pronounced as the ultimate state is approached. Such concrete behavior is an important constituent of the overall input required for the structural analysis of concrete structures. Information on the strength and deformational properties of concrete is usually obtained by testing cylinder or prism specimens under 1-D uniaxial compression, and then an elastic-plastic 3-D model is proposed to match the 1-D case without actually performing triaxial testings under generalized 3-D stress states. Such a practice is not always reliable, since using the artificial constitutive elastic-plastic continuum based 3-D model to represent a discontinuous material like concrete is always questionable. In attempt to reduce laboratory expenses, one would make predictions of a material's behavior through numerical simulations, with the primary goal being to accelerate a normally trial and error experimental processes. The recent dramatic increase in computational power available for mathematical modelling and simulation raises the possibility that modern numerical methods, such as discrete element method (DEM), can play a significant role in the analysis of granular materials including concrete. The generalized 3-D stress states will be simulated using DEM along different stress paths for a concrete specimen, with a focus on the softening and failure stages due to the presence of flaws and how the bond at the contact affects these.
PhD Project: Experimental and numerical investigation of textile reinforced mortar for strengthening of RC members at elevated temperatures
Abstract:The use of fibre reinforced polymer (FRP) has gained a lot of attention in recent years as a strengthening and repair method. The composite is known to be light weight and strong. However, one of the major drawbacks of FRP is its poor performance at elevated temperature. Textile reinforced mortar (TRM), on the other hand, has better fire resistance properties. TRM is also cheaper, using cement instead of a strong epoxy. Studies to understand the behaviour of TRM are rather limited and further investigations are required to understand its mechanism especially at high temperature. This project proposes to study the thermo-mechanical properties of TRM at ambient as well as elevated temperatures. A special focus will be devoted to finding if the fire resistance of the composite can be improved by adding additives to the mortar. In addition, full scale tests of reinforced concrete beams externally reinforced with TRM will be performed to assess its strengthening performance at elevated temperatures. Finite element modelling will be required for validating the experimental findings.
PhD Project: Experimental and analytical investigation on the behaviour of masonry structure strengthened with Textile Reinforced Mortars (TRMs) subjected to elevated temperatures
Abstract:Masonry structures are resistant to weakening with increasing temperatures. In addition, in the event of fire, they are expected to perform well in their load-bearing capacity and thermal insulation. This research tries to find answers to the following and other associated questions regarding strengthened masonry structures with TRM system. Textile reinforced mortar (TRM) is a composite material comprising fibric textile embedded in cementitious matrix. To achieve this goal, by applying international standards and regulations, several types of strengthened masonry structure needs to be investigated. Additionally, this research would lead new approaches and numerical model of TRMs in strengthening the masonry structures and better understand their reactions against fire. Applying strengthening materials needs be verified to confirm that they do not have destructive impact on the resistance of masonry structure against fire. Plus, by improving resistance of masonry component against fire, less materials and thinner walls and columns would be required and this would save economically in building masonry structures.
PhD Project: Study on the flow structure of asymmetric compound channel
Abstract:Compound channels (i.e. a deep main channel with associated shallow floodplains) play an increasingly important role in flood control project, river ecological restoration, urban river landscape design, and water environmental protection. Compound channel flow is far more complex from simple channel flow. Recent studies show that the momentum exchange has a significant impact on the flow structure of both symmetric compound channels and asymmetric ones with one floodplain, which have different flow structures. Asymmetric compound channel with two floodplains widely exists in natural rivers, but has not been studied ever before. This project aims an in-depth study on the flow structure of such a commonly-existing compound channel. Through the experiment study combined with numerical simulation method, we can obtain a comprehensive understanding of momentum exchange between main channel and floodplain, in order to accurately predict flow velocity, shear stress distribution, and channel capacity. The outcome will provide a scientific basis for river flood regulation, urban river landscape design, flood risk and environmental assessment, and the transport and control of pollutants.
The primary aim of this project is to understand the flow structure of an asymmetric compound channel by:
1) Investigating velocity and turbulence characteristics of asymmetric compound channel flows via experiments (mainly) and CFD modelling
2) Studying the flow resistance and discharge, including the zonal discharge (main channel and floodplain respectively)
3) Develop an approach for predicting flow resistance, velocity distribution and discharge including zonal discharge using the results from Objectives 1 & 2.
PhD Project: Potential of Sustainable Functionally Graded Concrete Pavements
Abstract:China has undergone rapid economic development over the past few decades and with it an equally rapid expansion of its road network. This trend is likely to continue and since environmental issues are becoming ever more important, it is essential that sustainable solutions are utilized in infrastructure development. Therefore, it is necessary to explore the use of different economical and environmentally friendly solutions for producing pavements. The functionally graded material concept may be applied to concrete to create more efficient structures, and the combination of this concept using recycled aggregates and fibres as concrete reinforcement would improve the technological and environmental drawbacks of traditional concrete. This proposed project aims to investigate the feasibility of using functionally graded concrete (FGC) fabricated with steel fibres and recycled aggregates to produce pavements. In that sense, different types of FGC mixes will be studied and compared, and optimization methods and control systems will be proposed and a sustainable analysis comparing the different FGC will be performed to determine the feasibility of their use on pavements.
PhD Project: Exploring the mechanical behaviour of granular materials considering particle shape characteristics: a discrete element investigation
Abstract:Granular materials are ubiquitous on the earth and exhibit intricate behaviour due to its heterogeneous and discrete in nature. Understanding the mechanics of granular materials is pivotal to a wide range of engineering and industrial applications. It is well known that the properties of constituent particles intrinsically control the macroscopic behaviour of granular materials. In particular, particle shape is one of its which underpins many facets of the mechanical behaviour, including packing density, strength and deformation. Yet, there is no standard particle shape which can forecast the true behaviour of granular material that exist in nature. This project aims to investigate the influence of particle shapes on the macro and microscopic behaviour of granular materials using the discrete element method (DEM).
PhD Project: A System Dynamic Model for Assessing Environmental Benefits from Recycling Construction Waste during Construction Stage
Abstract:Large scale of urbanization and city renewal has generated too much construction waste, which leads to significant environmental influences. Recycling construction contributes to sustainable development of construction industry and better environmental benefits. This proposed research aims to better understand the environmental benefits of recycling construction waste in construction stage. STELLA software will be adopted to develop system dynamics model to assess the environmental benefits of recycling construction waste. The findings of the proposed research are expected to provide reliable and scientific support on construction waste decrease and recycle.
PhD Project: Cold-formed Steel Joist and High-Strength Concrete Slab Composite System.
Abstract:Flooring systems are considered the largest contributor to the dead load of steel buildings, especially high-rise ones. However, the reduction in weight offered by composite floors has made them the preferred floor system in recent decades. The underlining idea of composite construction is to take advantage of both steel and concrete material properties while minimizing the disadvantages inherent in them. The use of cold-formed steel joist as an alternative to hot-rolled steel in composite floor systems has been gaining significant interest lately. This is due to some of its advantages over hot-rolled steel which include environmental-friendly production and higher strength-to-weight ratios. However, cold-formed steel application is often limited by buckling phenomena due to light gauge sections. Besides, the codes of practice do not adequately provide for the design of cold-formed steel composite sections. In light of that, this research aims to develop an efficient composite beam system for short and medium-span applications, and to provide validated analytical and numerical models for the prediction of its structural properties and behaviour.
PhD Project: Numerical and experimental investigations of compressive behaviour of FRP-confined waste-containing concrete columns.
Abstract:Prosperous construction industry causes enormous carbon-dioxide emission and demolished building wastes, which have significant negative environmental impacts. The utilisation of recycled wastes in concrete production has been proved to be an effective approach to mitigating these environmental problems. However, extensive studies have shown that using recycled wastes in concrete can lead to a decreased performance of concrete in aspects of workability, strength, stiffness and durability. Although various strengthening techniques were developed, further investigation on the behaviour of strengthened concrete is required, and more experimental data are expected to refine existing constitutive models. In order to improve the mechanical properties of waste-containing concrete and explore its potential in structural applications, this project will focus on the compressive behaviour of fibre reinforced polymer (FRP) confined waste-containing concrete.
PhD Project: A system dynamic model for assessing environmental benefits from recycling construction waste during construction stage
Abstract:The Construction waste is a critical issue in China. The recycling construction waste during construction stage is an effective method for mitigating environmental impact of construction waste. However, recycling construction waste in the construction stage in China is still in the early stage in the practice mainly because the recycling construction waste during construction stage is a very complex system including the impact and contributes of stakeholders, designers, contractors and government policies resulting in sophisticated interactions and multiple feedbacks. This research will provide a dynamic approach systematically assessing the environmental benefit of recycling construction waste during construction stage by developing a SD simulation model. It could be anticipated that the research outcomes could provide valuable scientific evidence to stakeholders to better understand the environmental benefit of recycling construction waste during construction stage and make decision based on the result. The methodology of this research could provide a valuable reference for researchers who are willing to conduct similar research using SD model approach.
PhD Project: Sustainable Building Construction: Mix Design of Papercrete
Abstract:This project aims to investigate a way to facilitate the use of papercrete, which is made of recycled short-fiber cellulose, Portland cement, water and additive mixture, and try to establish the systematic production processes of papercrete. At the first stage, according to the results of the material performance testing such as mechanical properties, the characteristics of single units are investigated, which lead to the optimal mix design to bed is covered. At the second stage, based on the data of experiments to be obtained and material specifications given in ASTM standards, relatively comprehensive testing standards of the papercrete will be able to be developed and established. At the third stage, by means of thoroughly analyzing the properties of papercrete, e.g. environmental benefits and/or commercial potential as well as other applications the feasibility and substantiality of papercrete in future construction industry will be demonstrated.
PhD Project: Sustainable Stormwater Management in China: Focus on implementation of LIDs in Sponge City Programme
Abstract:The sustainable stormwater management practices have been developed and successfully implemented in many countries, such as Low Impact Development (LID) in the US, Sustainable Urban Drainage System (SUDS) in the UK, Low Impact Urban Design and Development ( LIUDD) in New Zealand and Australia's Water Sensitive Urban Design (WSUD), etc. China formally announced a policy initiative to build “sponge cities” designed to tackle urban water problems, flooding and stormwater management in 2014, and the design of LID stormwater system is a significant process in the programme. This project will carry out the study on the implementation of LIDs in China’s sponge city programme, focus on: (1) assessing the hydrologic performance of different designs of LID practices in the study catchment, and identifying the optimal design for more effective management of stormwater runoff and mitigation of local scale flooding. (2) examining the effectiveness of the LID design under high precipitation events for further developing a resilient stormwater system to cope with extreme rainfall events. (3) modeling future scenarios to investigate the feasibility of the LID stormwater system and its response to potential future changes.
PhD Project: Displacement monitoring of civil Engineering structures using laser scanner
Abstract:In this research a 3D laser scanner was used to monitor displacement of retaining structures for excavation, including a ring beam and a reinforced soil mixing wall (SMW) at an open excavation site. Eight scans of the retaining structures were taken during and after the excavation. 3D point clouds of the retaining structures produced with these scans were registered and analysed to determine displacements of the retaining structures. Several cloud comparison methods were applied, including PAM, C2C, C2M and M3C2, to identify displacement along the length of ring beam and height of the SMW. The displacement obtained using the cloud comparison methods were validated against displacement measured by inclinometer and total station. Observation of deformation of surface soil layer on SMW falsified displacement estimation. Then, a machine-learning method (CANUPO) was applied to detect and delete positions affected by surface soil collapsing, and the displacement was re-estimated based on the revised point clouds. The revised displacement profile showed better consistency than the initial displacement profile. 3D laser scanning technique can provide structural displacement profile at high resolution in a wide range but its accuracy is marginally lower than the general requirement of structural monitoring. Therefore, it is concluded that laser scanning can act as a supplementary but not a replacement to the traditional structural monitoring techniques. It is suggested further research to be conducted on the development of 3D laser scanner and analysis of 3D point clouds to further realise the application of 3D laser scanning technique in structural monitoring.
PhD Project: Multi-agent Real-time Simulation of Light Train Network Energy Sustainability Analysis
Abstract:The current main control methods in the rail transit field are in a centralized form, which is based on the interaction between the ground side supervising system and the onboard side controlling system. The centralized control might lead to heavy computational loads when the central controller needs to manage a large number of trains simultaneously. The research aims to propose a multi-agent system (MAS) that enables trains to exchange information with other trains directly and make decisions. The MAS has the potential ability to reduce the calculation load of the central controller and to improve the information exchange efficiency. The results are presented in a number of publications listed below.
PhD Project: Information extraction from large point cloud datasets
Abstract:Terrestrial laser scanning (TLS) is a sensing technique that has been used widely for mapping the terrain surface for a range of applications. For example, multi-temporal TLS data can be used to measure surface movements caused by landslides. The data acquired consist of a set of topographic data points known as a point cloud. In TLS survey campaigns, it is a common practice to oversample the terrain surface. As a result, the spatial resolution of a TLS point cloud is often very fine, bringing great challenges for data processing especially when such type of data is exported to third-party software for further processing. In such cases, it is often necessary to select a subsample of a lower spatial resolution from the original point cloud (i.e. data sampling) while a user-define accuracy requirement is met. However, there is still a lack of comprehensive study on data sampling of TLS point clouds representing terrain surfaces, which forms the focus of this project.
PhD Project: Effect of Vegetation Patch on Compound Channel Flows
Abstract:A compound vegetated channel commonly exists in natural environment. Over recent decades, many researchers have taken interests in this field. The hydraulic characteristics of flow over vegetated compound channels are complex. Basically, vegetation affects significantly on the flow resistance and turbulence, resulting in affecting sediments, nutrients and contaminants transportation. Thus, understanding of the vegetation impact on flow structures is important for water resources utilization. However, most of the attention on vegetated channel flow is focusing on straight channels or symmetric compound channels, there are rare studies investigating the vegetation impact on asymmetric compound channels. In order to fill this research gap, this study aims at researching the impact of vegetation patches on flow structure (i.e. flow velocity, flow resistance and discharge rate) of compound channels.
The theoretical prediction of this research is based on SKM (Shiono and Knight Method) and the analytical solution is mainly developed from (Stone and Shen, 2002). A series of experiments would be conducted for model analysing. This study will investigate the effect of vegetation density, vegetation arrangement, vegetation height (related to emergent or fully-submerged), geometry characteristics and discharge on the flow structures. Given the simplicity, only rigid vegetation (represented by dowels) is simulated in this research. However, as flexible vegetation is widely observed in natural waterways and the flow characteristics over flexible plants are found to be significantly different from those over rigid plants, future research of flexible vegetation impact on flow structures is recommended.
PhD Project: Bio-Based Cementitious Composites with Recycled Wastes
Abstract:Replacing aggregate and cement by some recycle wastes, in concrete production, will not only decrease the solid waste pollution, but also eliminate pollution caused by producing new material. Different recycled waste has different influence on prosperity of concrete. At the same time, it has been evidenced that bacteria can heal concrete by producing calcium carbonate (CaCO3) precipitation to fill cracks and holes inside of concrete. Therefore, this project will practice bio-based self-healing technic for modifying concrete with various recycles wastes such as fly ash (FA), waste crumb rubber, waste ceramic and waste glass and obtain the performance of the concrete including mechanics strength, density, porosity, water absorption and durability.