This study investigates the shear behaviour of corrosion-damaged reinforced concrete Tbeams repaired with fibre reinforced polymer (FRP) systems. Nine beams with different corrosion levels (0% (uncorroded), 7% and 12%) and different strengthening methods were tested. Both the embedded Carbon-FRP rods and externally bonded Carbon-FRP sheets were effective in enhancing the shear strength of tested beams. The test beams were modelled using nonlinear three dimensional half models in the finite element (FE) package TNO Diana. The shear force capacity, shear force-deflection graphs and crack patterns at failure were used to validate the FE models. Reasonable agreement was obtained between the experimental and numerical results. A parametric study investigating the effect of concrete strength, steel-to-CFRP shear reinforcement ratio and shear span-to-effective depth ratio was carried out. The FE predictions suggest that the embedded CFRP shear contribution decreases with the increase in steel-to-CFRP shear reinforcement ratio and shear span-to-effective depth ratio. Finally, the FE predictions were compared with the predictions of Concrete Society TR55 design guidance. The results suggest that TR55 overestimates the shear strength enhancement offered by embedded CFRP rods.

HCCI is the process which a relatively homogeneous mixture of air and fuel auto ignites through compression. HCCI engines can have high thermodynamic cycle efficiencies, with low levels of emissions of nitrogen oxides (NOx) and particulate matter (PM). However due to the nature of the combustion the operating envelope is quite small compared to conventional internal combustion engines. A powertrain system centred on a supercharged HCCI engine with on-board thermal management was developed that extends the operating envelope of an HCCI engine. To achieve controlled auto-ignition across a wide range of engine conditions, a system for management of flow and temperature was installed at the air intake to enable the necessary regulation of temperatures and pressures at the inlet ports. The system includes a heat exchanger to heat the charge air, a supercharger to boost the charge air pressure, supercharger bypass and finally an intercooler, so that a wide range of combinations of pressures and temperatures can be achieved at the intake ports. In order to facilitate this control, a complete simulation model of the thermal system for a pressure-boosted multi-cylinder HCCI engine was developed. The model implements a dynamic mass and enthalpy balance model running in real time for the air intake system of the multi-cylinder HCCI gasoline engine and auxiliary components. The model is capable to calculate heat flux, mass flow, pressure and gas temperature distribution for the whole engine thermal management system however it does not take into account the turbulent nature of flow especially where hot and cold gas mix. Therefore an elaborate CFD model of the Thermal Management system has been compiled for evaluation of the computed flow field and analysis of the thermal system performance by the use of the CFD tool ANSYS CFX.

This research investigates the seismic responses of lightweight acceleration-sensitive non-structural components (NSCs) integrated on irregular multi-storey reinforced concrete (RC) structures designed on different ground types. Dynamic nonlinear finite element analyses of the primary-secondary systems were conducted to provide insight into the seismic response of the NSCs and to evaluate the accuracy of Eurocode 8 (EC8) predictions when the NSCs are attached to the flexible sides along the heights of the primary structures (P-structures). Various sets of natural and artificial earthquake records consisting of 70 accelerograms were utilised. The effects of the plan and vertical mass irregularities were investigated. The NSCs were modelled as vertical cantilevers fixed at their bases with masses on the free ends and varying lengths so as to match the frequencies of the P-structures. A full dynamic interaction is considered between the NSCs and P-structures. The results suggest that the recommendation of the EC8 underestimates the NSCs’ accelerations at the flexible sides of irregular RC P-structures when the NSCs’ periods match those of the P-structures. Consequently, a modification on the existing EC8 design equation is made for the calculation of the maximum acceleration amplification factors of the NSCs taking into account the effects of both the torsion and the maximum seismic capacity of the P-structure.

Glass and laminated glass are widely used for structural members in industry. To investigate how they fracture under impact as well as the subsequent fragmentation, the combined finite-discrete element method (FEM/DEM) was employed in this thesis. The mode I fracture model was extended for glass by changing the strain softening curve to a bilinear-like exponential decay shape. Analysis based on this model was performed and numerical examples in both 2D and 3D were investigated. Parametric study was carried out and conclusion was reached that the tensile strength, fracture energy and thickness are the top three parameters in improving the performance of monolithic glass under impact. Two mixed mode I + II fracture models (the elasto-plastic fracture model and the scaling model) were developed for the glass and the interface in laminated glass. The elasto-plastic model reached some similarity with the Mode I model, while some modification is needed for the scaling model. Results on laminated glass from the FEM/DEM were compared and verified with that from FEM, DEM and experiments. Parametric study on the laminated glass was performed, showing better capacity in energy absorption over monolithic glass.

This research aims to describe the effect which changing the geometry of confining structures has on transient aerodynamic effects induced by passing high-speed trains. A moving-model high-speed train was fired past walls, partially-enclosed tunnels, and single-track tunnels. A control experiment was carried out in the open air. 3D air velocity components and static pressure were measured inside the structures. The main findings are as follows. The durations and magnitudes of the pressure loads and maximum air velocities were found to be dependent on: the lateral separation of the walls; whether walls on both sides of the tracks are placed symmetrically or asymmetrically; the longitudinal positioning of the sensor in relation to the length of the tunnel; the cross-sectional area of the tunnel; the tunnel’s length in relation to the train’s length; and, finally, the size of an opening in the cross-section of a tunnel in relation to the tunnel’s internal perimeter. Maximum velocities were affected by confinement as a result of changes to: helical vortices in the wake; durations and magnitudes of the pressure fluctuation around the tail; the piston effect in tunnels; the boundary layer shape; and secondary flows induced by pressure gradients in the tunnel cross-section caused by vents.

Trace nutrients (metals) supplementation has been demonstrated to have a beneficial effect on the welfare of anaerobic digesters but there was a lack of information on the chemistry controlling their fate. The aim of this research was to determine the reactions governing the chemical behaviour of metals in anaerobically digested sludge and predict the fate of those metals when supplemented as MeEDTA. After the assessment of a wide range of analytical techniques, a suite of suitable analytical techniques1 were used to determine the metals behaviour in two case studies of metals supplementation: iron dosing and MeEDTA supplementation. The behaviour of the metals was controlled by the solid phase throughout a primary reaction (sulphide precipitation) and secondary reactions (phosphate precipitation, adsorption and organic complexation). The competition between the strength of metal's binding and EDTA complexation controlled the fate of the supplemented metals in anaerobic digesters. Transfer of CoEDTA in the solid phase was found to be divided into two reactions, where the second has a slow kinetic depending on the availability of the counter-ion reacting with EDTA. A key conclusion was that the presence of weaker metal-bound compounds mixed with strong sulphide precipitates changed the understanding of metals speciation, especially concerning their potential availability and consequently their behaviour as trace nutrients.

The research described in this thesis proposes a new,novel evaluation ‘framework’ and accompanying operational ‘model’, the ‘SUURE’ (Sustainable Underground Use Resilience Evaluation) ‘framework’, which adopts a socio-ecological systems (SES) approach to evaluation, combining sustainability science and resilience theory, at the same time incorporating a range of interdisciplinary tools and methods to achieve this. It purposes at its core to aid in sustainability evaluation of urban underground space, by evaluating the process to the outcome of sustainable solutions i.e. the capacity to adapt to change in different steady states. In consequence, a fundamentally different approach to planning that utilises future socio-ecological scenarios (NSP, PR, MF and FW) is incorporated in the ‘framework’ as a means of evaluating through its operational ‘model’, the sensitivity of investment decisions made today in the name of sustainability i.e. will the proposed engineering sustainability solution continue to deliver its intended function into the future, whatever that may be. The SUURE operational ‘model’ was employed as a proof of concept to the case study area of Birmingham Eastside, evaluating the potential use of multi-utility tunnels (MUT) in Eastside as a means of engendering sustainable and resilient use of urban underground space, through sustainable utility placement, both now and into the future. The flush-fitting MUT was found to be having the highest overall baseline (present-day) performance resilience index ratio at mean of 0.739, the shallow MUT second at 0.656, and the deep MUT last at 0.212. With regard to the evaluation of continued MUT functional performance into the future (whatever that may be), all three MUT options, if implemented today in the name of sustainability, would continue to deliver and retain their core functional performance, the deep MUT showing the most significant increase across all evaluation clusters (social, economic, physical, bio-physical and location aspects).

Multiple studies have shown the importance of transition metals for the microorganisms involved in anaerobic digestion. Deficiencies in metals can translate into suboptimal digester performances and therefore where present an opportunity to stimulate anaerobic digestion exists. Previous supplementation studies that have used EDTA complexed metals have shown conflicting results. Assays supplemented with cobalt-EDTA on its own consistently responded to a level equal to or higher than that from assays supplemented with a combination of metals. The results seemingly indicate that cobalt was the most commonly deficient metal in the sludge digesters. However this study has raised questions about the bioavailability of other metals as EDTA chelates, particularly nickel-EDTA. Differing levels of bioavailability for different EDTA complex metals explain how conflicting results for EDTA complexed metals can exist. Metal deficiencies were present 69% of the time in the wastewater sludge digesters samples. Given the questions raised about the bioavailability of metal-EDTA chelates the prevalence of deficiencies was likely to have been higher. At a site specific level it was found that a lower than expected Vmax for a given sites acetoclastic methanogen population corresponded with a positive response from supplementation and therefore it can act as an indicator of metal requirement.

Urban water distribution systems (UWDS) are highly inter-connected and under many uncertainties from water demand, pipe roughness, and component failure. Accurate projections of these uncertainties are almost impossible, and thus it may not be a proper method to design the system to meet its performance criteria for the forecasted scenario. The system is designed for the deterministic not for the uncertainties, as a result it may not be efficient or effective to be operated under different future scenarios. Flexible design is shown as a useful strategy to cost-effectively respond to uncertainties because of its consideration of uncertainties in advance, and has been successfully applied in many engineering systems. The objective of flexible design is to identify flexibility sources in UWDS and embed them into the system design to respond to uncertainties. The thesis discussed different terms to define the property of the system to respond to uncertainties and proposed a definition of flexibility for UWDS. It then proposed different measures to indicate flexibility value and introduced an efficient method to handle numerous uncertain parameters in the model. It also develops an efficient method to identify high value flexibility sources based on the Flexibility Index. Finally the thesis presents a flexibility-based optimisation model that enable water engineers to compare different flexible design alternatives and generate optimal solutions. A definition of flexibility in UWDS is proposed to illustrate broadly its property to respond to uncertainties, since it is not so useful, or at least in this thesis to distinguish similar terms to define the property of the system to respond to uncertainties. Identified flexibility sources by the proposed method is not useful for the flexibility-based optimization model to design a system, but it might be a powerful tool to locate the weak points in the system or provide better update options during rehabilitation of the system. The computational efficiency of the proposed flexibility-based optimisation model was demonstrated by dramatic decreasing on the number of the required hydraulic simulation in the case study. Flexible designs in the case study are more expensive than inflexible design, but have better hydraulic performance under uncertainties.

Organic matter (OM) in drinking water treatment is a common impediment responsible for increased coagulant and disinfectant dosages, formation of carcinogenic disinfection-by products (DBPs), and microbial re-growth in distribution system. The inherent heterogeneity of OM implies the utilization of advanced analytical techniques for its characterisation and assessment of removal efficiency. Here, the application of simple fluorescence excitation-emission (EEM) spectroscopy to OM characterisation in drinking water treatment was presented. Monthly raw and clarified water samples were obtained for 16 UK surface water treatment works. Fluorescence EEM spectroscopy was used for the assessment of total organic carbon (TOC) removal and OM characterisation. Fluorescence peak C intensity was found to be a sensitive and reliable measure of OM content and hence an indicator of DBPs presence. Fluorescence peak C emission wavelength and peak T intensity (reflecting the degree of hydrophobicity and the microbial fraction respectively) were found to characterise the OM; the impact of both on TOC removal efficiency was apparent. OM fluorescence properties were shown to predict TOC removal, and identify spatial and temporal variations. The simplicity, sensitivity, speed of analysis and low cost, combined with potential for incorporation into on-line monitoring systems, mean that fluorescence spectroscopy offers distinct advantages over other THM precursors characterisation techniques.