Refurbishments have different features in comparison with new build projects. This refers mainly to the fact that they are carried out in an existing asset that might remain in operation. Such characteristics increase the complexity inherent to construction settings. Yet, studies indicate that mainstream practices, that are not capable of dealing with complex projects, are predominantly used for managing production. Prior research suggests that the use of such an incompatible management approach is likely to lead to poor performance. Indeed, problems in managing refurbishments have been identified in several countries. Despite this troubling scenario, the management of refurbishment works has not been properly addressed in the current research agenda. There are numerous studies related to the broad refurbishment area, but only a small number refer to the way those projects are managed. Moreover, the majority of studies about this topic have not been based on a proper theory of production. Clearly, there is a gap in this research domain. In order to fill such a gap, this research aims to developing a method for construction management in refurbishment projects, with the purpose of improving production performance, by indicating appropriate approaches of production control. The method comprises a conceptual model of refurbishments, a framework for project characterisation, and a list of managerial solutions, grounded on a robust theory of production and suited to the context of refurbishments. The constructive research approach is adopted in the study. Two rounds of empirical studies were conducted throughout the research. Firstly, two studies were carried out to obtain a deeper understanding of the topic investigated and to develop the initial version of the method. Secondly, a study was conducted to implement and refine the artefact. Thirdly, a focus group was organised to evaluate the utility of the method, to refine it, and to examine its scope of applicability. The main theoretical contributions of the study, embrace the conceptual model of refurbishments to support effective construction management, the framework having project dimensions for helping managers to cope with the management of complexity innate to refurbishments, and the framework of managerial solutions for production management. In practical terms, the study showed that the application of the method assisted managers in choosing suitable practices for managing construction in a retrofit project and contributed to enhance project performance. Moreover, it is contended that the method can be used to help organisations to get started on lean in refurbishment projects.

Uptake of geothermal heat pump (GSHP) systems has been slow in some parts of the world due to the unpredictable operational performance, large installation space requirement and high installation costs. Therefore, design modification was searched in order to improve the feasibility. With regard to relatively small impact of the construction costs, efficient thermal energy collection was targeted in horizontal ground-loop systems with shallow underground construction. The research started with a sensitivity analysis of the underground heat collection system using computational fluid dynamics (CFD). The results indicated essential design parameters to enhance the performance. Strategies to improve one of the parameters, thermal conductivity of soil surrounding the heat exchanger, were investigated through lab experiments. Subsequently, further design optimisation with the CFD intended to select the most competitive modified design against the existing design. It was discovered that an indication to achieve economic and practical modifications for efficient heat collection was to increase the moisture content of sub-soil up to the optimum moisture content (OMC). Annual operation analysis with the CFD disclosed that additional costs for even simple design modifications could easily worsen the payback period. Consequently, solutions to improve the performance of the GSHP within reasonable payback period were proposed.

Bridge structures have an important role in economic, social and environmental aspects of society life. Bridges are also subject to a natural process of deterioration of construction materials, as well as natural and environmental events such as flooding, freezing, thawing etc. Health monitoring and assessment of the structural integrity of bridges have been the focus of engineers and researchers for decades. Currently, the various aspects of bridge health are monitored separately. However, measuring these aspects independently does not give the overall health of the bridge and crucial indicators of structural damage can be neglected. Generally, bridge health assessments take the form of individual NDT (non-destructive techniques) detecting individual defects. However value can be added to these results by combining and comparing the findings of several different NDT surveys. By completing this, a more accurate assessment of bridge health is obtained. This increases confidence in the decision as to whether remedial action is necessary. In this thesis an integrated bridge health monitoring approach is proposed which applies several NDT specifically chosen for bridge health assessments, thus achieving this added value. This method can be used as a part of a comprehensive bridge monitoring strategy as an assessment tool to evaluate the bridges structural health. This approach enables the user of this approach to obtain a detailed structural report on the bridge with all the necessary information pertaining to its’ health, allowing for a fully educated decision to be made regarding whether remedial action is necessary. This research presents the results of the applications of such methods on case studies utilising Ground Penetrating Radar (GPR), IBIS-S technology / system (deflection and vibration detection sensor system with interferometric capability) and Accelerometer sensors. It also evaluates the effectiveness of the adopted methods and technologies by comparing and validating the yielded results with conventional methods (modelling and visual inspection). The research presents and discusses processed data obtained by the above mentioned methods in detail and reports on challenges encountered in setting up and materialising the assessment process. This work also reports on Finite Element Modelling (FEM) of the main case study (Pentagon Road Bridge) using specialist software (SAP2000 and ANSYS) in order to simulate the perceived movement of the bridge under dynamic and static conditions. The analytical results output were compared with results obtained by the applications of the above non-destructive methods. Thus by using these techniques the main aim of this thesis is to develop an integrated model/approach for the assessment and monitoring of the structural integrity and overall functionality of bridges. All the above methods were validated using preliminary case studies (GPR), additional equipment (accelerometers for IBIS-S validation) and additional techniques and information (SAP 2000 and ANSYS were compared to one another and IBIS-S results). All of these techniques were applied on the Pentagon Road Bridge. This bridge was chosen as no information was available regarding its structural composition. Visual inspection showed the external defects of the structure: cracking, moisture ingress and concrete delamination was present in one of the spans of the bridge. The GPR surveys gave the position of the rebars and also signs of moisture ingress at depths of 20cm (confirmed using velocity analysis). IBIS-S gave results for the deflection of the structure. FEM was used to model the behaviour of the bridge assuming no defects. To achieve additional model accuracy the results of the rebar position were input in to the model and it was calibrated using IBIS-S data. The deflection results from the model were then compared to the actual deflection data to identify areas of deterioration. It was found that excessive deflection occurred on one of the spans. It was thus found that all NDT indicated that a particular span was an area of significant deterioration and remedial action should be completed on this section in the near future. Future prediction was also completed by running simulations in ANSYS for increasing crack lengths and dynamic loading. It was found that if there is no remedial action excessive beam bending moments will occur and eventual collapse. The results of this research demonstrated that GPR provided information on the extent of the internal structural defects of the bridge under study (moisture ingress and delamination) whilst IBIS-S technology and Accelerometer sensors permitted measurement of the magnitude of the vibration of the bridge under dynamic and static loading conditions. The results depicted similarities between the FEM results and the adopted non-destructive methods results in location and pattern. This work can potentially contribute towards a better understanding of the mechanical and physical behaviours of bridge structures and ultimately assess their life expectancy and functionality.

The thesis presents an experimental investigation into the feasibility of using a slurry containing a micro encapsulated phase change material (MCPCM), n-eicosane, as a heat transfer fluid for enhanced latent heat transport. Increasing the convective heat transfer coefficient would permit the use of a smaller volumetric flow rate and reduce pumping power. The primary parameters investigated are the volumetric concentrations and flow rates. Measurements of thermal capacity of the novel slurries were performed using two techniques, standard differential scanning calorimeter (DSC) and thermal analysis (TA). Pumping power consumption, viscosity and pressure loss of the flowing slurries were investigated in order to determine the most suitable concentration of MCPCM used in the slurry, over the range 5-40%. The effects of repeated use of liquid-solid phase change particles upon melting and solidifying were studied using a small-scale rig of a closed loop circuit. The research work further involved the design, construction and tests the proposed system based on incorporating microencapsulated phase change material (MCPCM) within a fluidised and sealed double glazed panel, which could be integrated into building fabric. The use of a MCPCM slurry can improve the performance of a working fluid by as much as 52% compared to a single phase fluid. A concentration of 20-30% was the most suitable mixture for the working fluid due to the associated heat capacity and reasonable pressure drop. Measurement showed that a saving in pumping power of 12% could be obtained. The performance of the fluidised glazed energy storage system can be improved by up to 18% with the use of MCPCM slurry as a working fluid.

The current usage of site layout information in construction planning techniques is investigated, and the layout development methods used in other fields such as Architecture and Production engineering are also reviewed. The limitations, applicability and potential of these models is discussed. The layout of a construction site affects the manner in which construction plans are formed. This research is an attempt to isolate the site layout factors which are taken into account in the planning stages of a project. The layout of a construction site may be utilised in the formation of construction plans in two ways. Firstly, the large scale layout of the structures may influence the order in which the structures are built. Secondly, the small scale layout of the work within each individual structure will determine the order in which that work will be carried out. A model has been developed which uses the two types of site layout information for the structure and activity sequencing in the production of construction plans on a micro-computer. The practicality and performance of this model has been tested by comparison of the plans produced with those produced with other planning methods and those produced in industry. The feasibility of the integration of this model with Computer-aided design packages has been discussed with a view to producing construction plans automatically from the contract drawings.

Stabilised-soil cement building blocks are an established building material in many areas of the Less Developed World. This thesis has been split into three parts. Part A presented an overview of the process of soil-stabilisation and outlined the roles which soil structure and curing play in stabilisation. It examined methods of testing soils, highlighting errors presented in the published literature and presenting corrected testing procedures and unified plans for their implementation. Part B examined the conventional quasi-static block compaction process (slowly applied pressure) and established that no cost-effective increase in the compacted block density can be achieved by altering such moulding configurations as mould-wall roughness, mould-wall taper, number of applied pressure cycles and double-sided pressure application. The tests were also used to assess the plausibility of several theoretical mechanisms underlying quasi -static compaction. Cement may be traded against compaction pressure for a given final cured strength. The relation of compaction pressure and cement content to well-cured strength was established for 50 mm diameter cylinders and used to assess the financial benefit of high-pressure compaction. It was shown that savings in the cost of cement associated with high-pressure compaction were outweighed by the additional cost of such machinery. However there were additional benefits found to high-density compaction, beyond the saving in stabiliser costs. It was established that a highdensity moulding machine in the range £1000 - £1500 would allow these benefits to become cost competitive. Part C examined both experimentally and theoretically an alternative dynamic (impact blow) compaction process, establishing that optimised dynamic compaction may produce strength equivalent to quasi-static high-density moulding while requiring only 25-50 % of the energy. Five theoretical models of the process were developed and the Combined Airlock/Friction/Compression Wave Model was shown to have the most explanatory power.

Duisburg, Essen, Universiẗat Diss., 2003.

The Egan Report, changes to Part L Building regulations, and the importance of office workers is challenging designers to improve the construction process, reduce operational carbon emissions, and enhance occupant comfort for office buildings in the United Kingdom. This thesis proposes a double skin facade system with integrated environmental systems to overcome these challenges. The Facade deals with a number of conflicting requirements and a single-storey, naturally ventilated cavity, unitised Double Facade has been proposed to resolve them. The two key determinants for the Active Environmental System have been prefabrication and operational carbon emissions. To address these issues a decentralised system, comprising of a Reversible Air Source Heat Pump, Heat Exchanger, Active Beam and Active Trench is proposed, and integrated into the Double Facade. A key part of the design process has been working with industrial partners to develop the design and realise a full-scale prototype. This has been tested and evaluated in terms of key aspects of the comfort, weather and aesthetic performance. An appraisal of the product demonstrates that it achieves proof of concept; it is highly prefabricated and enhanced occupant comfort and carbon emissions targets can be met.

Urbanisation is associated with physical modifications of land surfaces and climate of a given area. Studies of urbanisation effect on urban climate of Klang Valley region is below par. This research aims to bridge the gap by using a coupled Weather Research and Forecasting (WRF) model with the NOAH Land Surface Model (NOAH) and Urban Canopy Model (UCM) – WRF/NOAH/UCM to investigate the urban climatology of Klang Valley and the urbanisation of Putrajaya over a decade. In addition, evaluation of the garden city concept adopted in the development of Putrajaya city is also conducted. The model is first validated against a network of meteorological observations in the region to determine its suitability for urban climate investigations. Climatological variables (near-surface temperature, relative humidity, and wind speed) along with land use and land cover (LULC) changes; planetary boundary layer height (PBLH), and urban heat/cool islands (UHI/UCI) of the area are also investigated. The model evaluation shows good performance over the region. LULC changes demonstrates strong influence in thermal climatology variations. A mean maximum UHI intensity of ~4.2 ºC was observed in the urban canopy-layer of the Klang Valley. Results reveal that urbanisation of Putrajaya leads to 2-m temperature increase at the rate of ~1.66 ºC per decade, with the area experiencing a mean UHI intensity of ~2.1 ºC per day. Other climatological variables vary accordingly with the urbanisation processes. Evaluation of the garden city concept indicates that the adopted concept causes a reduction in 2-m air temperature of the Putrajaya area, amounting to ~0.53 ºC per day; with vegetation contributing more (~0.39 ºC) to the daily reduction relative to water bodies (~0.14 ºC). Location of the city in the tropics accustomed with high intensity of daily solar radiation masked the cooling potentials of the concept to some extent.

No description available.