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Due to the demands of increasing population and environmental concerns, the high-speed train has become an important means of transportation in many countries. However, severe vibration induced by high-speed trains can occur when train speeds approach the speed of waves in the ground and track deflections can then become large. Consequently, the track and ground may no longer behave linearly. The aim of this work is to develop a three-dimensional model of vehicle/track/ground interaction in the time domain that can include the consideration of soil nonlinearity. A three-dimensional time-domain model of a coupled vehicle, track and ground has been developed in the finite element (FE) software ABAQUS. A new analysis approach has been adopted for modelling the moving vehicle without the need for a user-defined subroutine. The results from a track on a hemispherical ground model surrounded by infinite elements show good agreement with the results from a wavenumber finite element/boundary element method at lower speeds. However, significant differences are found for load speeds close to the critical speed for a homogeneous ground. This has been shown to be due to a relatively long transient in the numerical simulation that requires a considerable distance to achieve convergence to steady-state results. As a result, a very long model is required to derive the steady-state results. However, this becomes expensive because of the model geometry. Moreover, the results from the hemispherical model contain incorrect whole-body displacements due to the use of the infinite elements that make the ground model become unconstrained. Therefore, a cuboid model with a fixed boundary at the bottom is used for the further simulations to prevent these incorrect phenomena. Two different cuboid models, with or without the infinite elements at the sides, are compared. Finally, a wider cuboid model with fixed boundaries is used with appropriate Rayleigh damping which shows the best results and efficiency. A very long model, around 150~300 m, is required when the load speed is equal to the critical speed for a homogeneous soft ground. However, a shorter model is sufficient to obtain the steady-state results for a layered half-space. For a load moving close to the critical speed on a layered half-space, the track oscillates with a certain dominant frequency. An investigation is presented into the dependence of the oscillating frequency on the ground properties, taking account of the dispersive surface waves. Three different methods are used to investigate this oscillating frequency for a layered half-space ground and a parametric study is carried out. The oscillating frequency is found to vary with the speed of the moving load and tends to decrease when the load speed increases. It mainly depends on the shear wave speed of the upper soil layer and the depth of this layer. A formula is introduced to estimate this oscillating frequency in a layered half-space. Finally, soil nonlinearity is introduced in the FE model through a user-defined subroutine. The nonlinearity is specified in terms of the shear modulus reduction as a function of octahedral shear strain, based on data obtained from laboratory tests on soil samples. The model is applied to the soft soil site at Ledsgård in Sweden, from which extensive measurements are available from the late 1990s. It is shown that the use of a linear model based on the small-strain soil parameters leads to an underestimation of the track displacements when the train speed approaches the critical speed, whereas the nonlinear model gives improved agreement with the measurements. However, the results are quite sensitive to the choice of nonlinear model. In addition, an equivalent linear model is considered in which the equivalent soil modulus is derived from the laboratory curve of shear modulus reduction using an 'effective' shear strain. It is shown that the predictions are improved by using a value of 20% of the maximum strain as the effective strain rather than the value of 65% commonly used in earthquake studies.

High performance foiling catamarans are one of the fastest growing sectors in the sailing and sport industries, allowing athletes to perform in extremely fast and spectacular boats. These boats fly above the water with the aid of foils that not only provide horizontal side-force to counterbalance the aerodynamic forces from the sails, but also deliver vertical force that supports some or all of the mass of the boat. Exploring the possibility of using Passive Adaptive Composite (PAC) on the hydrofoils to control their pitch angle enables the boats to achieve a stable flight in a wide range of weather conditions. This thesis presents an experimental and numerical evaluation of bend-twist elastic coupling in composite passive-adaptive structures. Due to the lack of experimental validation in Fluid Structure Interaction (FSI) investigations, a full-field deformation of an aerofoil-shaped section under wind loading is measured. Moreover, the influences of structure deflection on flow behaviour are investigated by looking at the changes in flow features evaluated on a transverse plane downstream of the trailing edge. The experimental analysis was carried out at the University of Southampton R. J. Mitchell wind tunnel and involved the use of full-field non-contact measurement techniques such as high speed three dimensional Digital Image Correlation (3-D DIC) and stereoscopic Particle Image Velocimetry (PIV). After assessing the validity and repeatability of the experiments, the research focuses on the development of a numerical FSI investigation that involves the use of a structural and a fluid solver to simulate the aero-elastic behaviour of composite tailored specimens with different internal structures. The numerical analysis is developed as a tool to allow the design of a new structure able to achieve a constant level of lift force (corresponding to the weight of the catamaran) in increased flow speed. During the research project it was proven that the efficiency of the foils can be improved by tailoring the internal structure to induce smart coupled bend-twist toward a wash-out (feather) or wash-in (stall) position under increased loading.

This research project investigates the thermo-mechanical non-linear response of steel structures to combined long duration ( > 200msec) blast and thermal loads. Depending upon explosive size and standoff distance the thermal load can reach, and degrade a structure prior to the arrival of the blast load. The thermal load produced by explosive events can damage steel structures such that the damage from the combined thermal and subsequent blast load would be greater than or different to, the damage from the blast load alone. Parametric studies presented in this thesis examine the response of structural steel columns to a range of blast and thermal loading regimes and investigate the effect of parameters including connection type, compressive loads and thermal conductivity. Data from previous research is used to develop predictive algorithms calculating the thermal and blast load regimes from explosive events. Transient, non-linear, coupled (thermal and structural) analyses using the finite element analysis (FEA) program, LUSAS are performed on the structural steel columns. The design of, and results from a series of trials recording temperatures, thermal flux and pressures, and observing the response of 2mm thick steel plates, within a 41kg TNT equivalent (eq.) explosive fireball, is presented. The design of, and results from experimental trials investigating the response of structural steel columns to combined thermal, compression and long duration blast loads within an Air Blast Tunnel (ABT) are also presented. Results from both sets of trials are compared to predictive non-linear FEA models of the steel plates and columns, developed to provide verification of computational procedures used throughout the research project. Resistance curves for the vulnerability analysis of whole buildings to explosive events are presented. The curves represent the elastic and plastic failure mechanisms of structural columns to thermal and blast explosive loads. This research project demonstrates that under specific loading regimes steel structures can exhibit a thermo-mechanical, synergistic response to combined thermal and blast loads from explosive events. This has been achieved through detailed investigation into previous research, thorough and comprehensive parametric studies and a series of innovative experimental trials using M.O.D national testing facilities.

Many public sector construction projects in the Kingdom of Saudi Arabia (KSA) are marred by communication and coordination problems, with owners having to pay a high price for schedule delays and cost overruns. The process by which building information is conveyed to owners lacks standardisation, a holistic approach, and consistency. This often results in KSA public sector owners receiving building information in a variety of formats, resulting in buildings operating at sub-optimal levels and relevant building data being unavailable at required times to support decision-making and optimal operations and maintenance. Existing systems of data management within KSA public sector projects cannot match the demand of operations and maintenance, as buildings are becoming more complex, in terms of space management, energy demand management, and addressing environmental concerns, due to the functional requirements of modern infrastructure. This research focuses on investigating key technology and processrelated challenges in order to ensure smoother transition of information from project design and construction to maintenance and operation phases of a building’s lifecycle. This research aims to develop a framework to enhance data management in building handover practices of public sector construction projects in the KSA. This framework helps improve the operation and maintenance of buildings by establishing a relationship between the project design and construction team, and the operations and project maintenance team. The research identifies key data requirements for effective building handover from a Saudi client perspective. In order to achieve the research aim, an empirically based systems analysis of a singledetailed case study organization of Al Madinah Al Munawwarah, Regional Municipality in KSA was carried out. Substantial fieldwork was undertaken using both qualitative and quantitative methods to match specific research questions. The questionnaire survey provides a wider view of building handover practices in the KSA, while the qualitative study provided an in-depth understanding of the state-of-the-art in practice. Many tools were used to collect the data, including semi-structured interviews supplemented by survey questionnaires together with documentation review. The implementation of more than one method to collect the data was used in order to achieve data triangulation, to explore implementation of data management in building handover practices, and to provide a more an in-depth understanding. The finding of this research concludes some unique factors that affect the implementation of actual building handover practices within the public sector construction industry in KSA. These factors include: high manager turnover; lack of knowledge and experience; lack of use of technology; lack of training; lack of communication during project data at the Handover Stage; unclear responsibilities. However, the finding indicates that it is important for all managers in public sector construction to understand that the handover is started already at the beginning of the project. Furthermore, early handovers must be reviewed and strengthened during the final project handover. Also, the research findings confirmed that the lack of communication was possibly because of the fact that the project team is big and multi-cultural. Thus, the individuals were afraid to ask any questions as they assumed others would think that they were too inexperienced to understand some technical specifications. Hence, it is highly critical to define and use a clear communication procedure. Every manager is responsible for communicating internally and externally about status and issues. These findings will strengthen the existing literature on effective data handover at project completion stage and will narrow the gap in knowledge in KSA studies in particular and to Arab studies in general. Therefore, significant recommendations to the policy, practitioners, and researchers, within both the public and private sector projects, are made to aid and improve construction industry practices. This research provides specific original findings, which include an in depth understanding of factors that affect the facilitation of data management in building handover practices of construction projects in the KSA via a case study conducted within the KSA public sector construction context. This research is the first study in KSA regarding issues that affect data management in building handover practices of construction projects in the KSA. It is also the first academic study of the Al Madinah Al Munawwarah, Regional Municipality in KSA.

Grouting has been used in ground engineering since the early 19th century. Grouts are injected into the ground both for the creation of hydraulic barriers and for ensuring ground stability. Example applications are dam sealing, underground isolation of waste disposal sites, stabilisation of mine workings and prevention of water ingress during tunnelling. A key problem facing the grouting industry is that once the grout has been injected into the ground, it is impossible to detect where the grout material has gone. As a consequence, the integrity of the hydraulic barrier, or in the case of ground improvement the filling of all significant voids, cannot be guaranteed. This leads to huge conservatism in the industry, with large numbers of unnecessary injection boreholes being drilled. This Ph.D. thesis aims to create a detectable grout by the addition of magnetic materials to traditional cementitious grouts. Laboratory experiments have been undertaken to determine both the magnetic susceptibility and engineering properties of the detectable grout. These experiments have shown that, with the addition of magnetite, a viable detectable cementitious grout mixture can be produced. Samples of the detectable grout were then produced for use in two field trials. The first field trial provided the proof of concept that the grout could be detected both outside of the laboratory environment and at depth. The second field trial established how the magnetic field of the detectable grout changed with distance. The rate of decay of the magnetic field in all directions was established, with the grout being detected at a maximum distance of 3 m. This thesis has provided the first proof of concept that a magnetically susceptible cementitious grout, once injected into the subsurface, can be detected with a magnetometer. The data could then be used to determine the location and shape of the grouted rock volume. This detectable grouting system has the potential to reduce the inefficiencies and uncertainties currently present in the grouting industry.

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