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A non-linear finite element model has been developed to analyse reinforced concrete structures taking into account : (1) non-linear concrete behaviour under biaxial stress, (2) progressive cracking of the concrete, and (3) interaction between the reinforcement and the concrete matrix commonly known as bond. Three dimensional reinforced concrete components are analysed by an approximate two dimensional plane stress model. Bond is considered to be a concentric layer surrounding the reinforcement modelled by a 6 noded rectangular 'shearing' element. The concrete is represented by 8 noded isoparametric membrane elements and the reinforcement by 3 noded isoparametric bar elements. The finite element model uses, an incremental iterative solution technique known as the 'Initial stress method' and a special solution technique to allow for cracking of the concrete. stiffnesses within elements are evaluated by numerical integration using Gaussian Quadrature, with elastic moduli stored at the sampling positions. The bond model is based upon an assumed non-linear relationship between bond stress and slip in which the localised ultimate bond stress' is a function of both the lateral pressures exerted by the concrete on the reinforcement and the radial contraction of the bar' due to Poisson's effect. Allowance is also made for the deterioration of bond when the slip exceeds a tolerance value. The concrete model is a non-linear elastic fracture model based upon the 'Equivalent uniaxial strain approach' as developed by Darwin and Pecknold (1974). Cracking of the concrete is assumed to be 'smeared' within the concrete element. Reinforced concrete components which have been analysed include; the ordinary pullout test, double ended pull out test, a transfer test, and a beam-column intersection. A small experimental programme was conducted to obtain reliable data as to the nature of the bond stress and reinforcement strain distributions in the double-ended pullout test, the transfer test and the beam-column intersection. To determine the reinforcement strain distributions, plain round bars or ribbed reinforcement bars in the case of the beam-column, were embedded in the concrete specimens with electrical strain gauges attached . The author's computer programs are explained and listed in the appendices.

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Noise and vibration are important design issues for many types of vehicles such as ships, cars, and aeroplanes. Structure borne sound, which may be of relatively high frequency, usually emanates from an engine or some other type of localised source and propagates through the vehicle. Excessive vibration levels, and thus structural damage, may occur while structural acoustic interactions may lead to unacceptable interior noise. In the analysis of energy transmission between plate structures, it is common practice to consider only bending modes (or waves) of the structure. However if the concern is with high frequency vibration analysis, then due allowance may need to be made for the presence of inplane shear and longitudinal modes. Due to the infeasibility of the industry standard technique, the Finite Element Method, at high frequencies, almost all of the studies that have investigated the importance of in-plane energy transmission have used Statistical Energy Analysis (SEA). In this study an existing dynamic stiffness method is extended to include in-plane effects, and used as a benchmark against which SEA is assessed. Additionally the Wave Intensity Analysis (WIA) technique, which is an improved form of SEA, is extended to in-plane vibrations, and used to identify some of the reasons for the poor performance of SEA in certain applications. All three methods are applied to a wide range of plate structures within the frequency range of 600 Hz to 20 kHz. While the response levels as predicted by the WIA are generally quite close to exact results, it has been found that although all of the requirements which are usually postulated for the successful application of SEA are fulfilled, SEA severely underpredicts the energy transmission in large structures because of the diffuse wave field assumption. It is also shown that the exclusion of in-plane modes may lead to sizeable errors in energy predictions unless the structure is very simple.

This thesis is concerned with the mass compressibility of fractured chalk and its influence on the settlement of shallow foundations. A review of the literature reveals nineteen case records of load-settlement behaviour from relatively small diameter « 1m) plate loading tests but only six welldocumented case records of the behaviour of shallow foundations on chalk. The plate loading tests indicate that highly fractured near-surface chalk undergoes yield at relatively low stresses (200 - 400kPa) resulting in a significant reduction in stiffness. This behaviour contrasts with that observed in other rock types with similar discontinuity patterns. For chalk it has only been observed in one case record for a full-scale foundation. Little is understood about the mechanisms causing yield. At the time of starting this research, based largely upon the experience ..gained from in-situ loading tests carried out at Mundford, Norfolk (Ward et aI., 1968), it was known that factors such as fracture spacing and aperture played an important role in controlling the load-settlement behaviour of shallow foundations. Little attention was paid to the large variation in intact properties displayed by the chalk. In this research nine 1.8m diameter plate loading tests have been carried out by the author on chalks with different intact mechanical properties and similar discontinuity patterns. These data are used to evaluate other in-situ tests (such as SPT, surface-wave geophysics and visual assessment) as means of providing parameters for the prediction of foundation settlement. The results of this research indicate that fractured near-surface chalk undergoes yield within the range of stresses likely to be imposed by shallow foundations and that the pre-yield stiffness of the rock mass is controlled to a large extent by the looseness of the fracture-block system, which in tum appears to be associated with the intact mechanical properties of the rock. The post yield-stiffness of the rock mass is generally about one tenth of the pre-yield stiffness and is relatively insensitive to the rock material properties.

In the construction sector, capturing the building product in a single information model with good interoperable capabilities has been the subject of much research efforts in at least the last three decades. Contemporary advancements in Information Technology and the efforts from various research initiatives in the AEC industry are showing evidence of progress with the advent of building information modelling (BIM). BIM presents the opportunity of electronically modelling and managing the vast amount of information embedded in a building project, from its conception to end-of-life. Researchers have been looking at extensions to expand its scope. Sustainability is one such modelling extension that is in need of development. This is becoming pertinent for the structural engineer as recent design criteria have put great emphasis on the sustainability credentials in addition to the traditional criteria of structural integrity, constructability and cost. Considering the complexity of nowadays designs, there is a need to provide decision support tools to aid the assessment of sustainability credentials. Such tools would be most beneficial at the conceptual design stage so that sustainability is built into the design solution starting from its inception. This research work therefore investigates how contemporary process and data modelling techniques can be used to map and model sustainability related information to inform the structural engineer’s building design decisions at an early stage. The research reviews current design decisions support systems on sustainability and highlights existing deficiencies. It examines the role of contemporary information modelling techniques in the building design process and employs this to tackle identified gaps. The sustainability of buildings is related to life cycle and is measured using indicator-terms such as life cycle costing, ecological footprint and carbon footprint. This work takes advantage of current modelling techniques to explore how these three indicators can be combined to provide sustainability assessment of alternative design solutions. It identifies the requirements for sustainability appraisal and information modelling to develop a requisite decision-support framework vis-à-vis issues on risk, sensitivity and what-if scenarios for implementation. The implementation employed object-oriented programming and feature modelling techniques to develop a sustainability decision-support prototype. The prototype system was tested in a typical design activity and evaluated to have achieved desired implementation requirements. The research concludes that the utilized current process and data modelling techniques can be employed to model sustainability related information to inform decisions at the early stages of structural design. As demonstrated in this work, design decision support systems can be optimized to include sustainability credentials through the use of object-based process and data modelling techniques. This thesis presents a sustainability appraisal framework, associated implementation algorithms and related object mappings and representations systems that could be used to achieve such decision support optimization.

Small scale laboratory experiments were conducted to study the dynamic mor- phology and rheological behaviour of fluid-particle mixtures, such as snout-body architecture, levee formation, deposition and particle segregation effects. Debris flows consist of an agitated mixture of rock and sediment saturated with water. They are mobilized under the influence of gravity from hill slopes and channels and can reach long run-out distance and have extremely destructive power. Better understanding of the mechanisms that govern these flows is required to assess and mitigate the hazard of debris flows and similar geophysical flows. Debris flow models are required to accurately deal with evolving behaviours in space and time, to be able to predict flow height, velocity profiles and run-out distances and shapes. The evolution of laboratory debris flows, both dry glass beads and mixtures with water or glycerol, released from behind a lock gate to flow down an inclined flume, was observed through the channel side wall and captured with high speed video and PIV analysis to provide velocity profiles through out the flow depth. Pore pressure and the normal and shear stress at the base of the flow were also measured. Distinct regions were characterized by the non-fluctuating region and the in- termittent granular cloud surrounding the flows. The extent of these regions was shown to be related to flow properties. The separation of these two regions allowed the systematic definition of bulk flow characteristics such as characteristic height and flow front position. Laboratory flows showed variations in morphology and rheological characteristics under the influence of particle size, roughness element diameter, interstitial fluid viscosity and solid volume fraction. Mono-dispersed and poly-dispersed components mixed with liquids without fine sediments, reveal a head and body structure and an appearance similar to the classic anatomy of real debris flows. Unsaturated fronts were observed in mono-dispersed flows, suggesting that particle segregation is not the only mechanism. A numerical simulation of laboratory debris flows using the computer model RAMMS (RApid Mass Movements Simulation) was tested with dry laboratory flows, showing close similarity to calculated mean velocities.