Considerable work has been done on the mechanical properties of coconut-fibre enhanced concrete. The primary test variables were the fibres weight fraction, and fibres aspect ratio. The addition of coconut-fibres significantly improved many of the engineering properties of concrete, notably torsion, toughness and tensile strength. The ability to resist cracking and spalling were also enhanced. However, the addition of fibres did not improve the compressive strength, as expected, due to difficulties in compaction which consequently lead in increase of voids. When coconut fibre was added to plain concrete, the torsional strength increased (by up to about 25%) as well as the energy-absorbing capacity, but there is an optimum weight fraction (0.5% by weight of cement) beyond which the torsional strength started to decrease again. Similar results were also obtained for different fibre aspect ratios, where again results showed there was an optimum aspect ratio (125). An increase in fibre weight fraction provided a consistent increase in ductility up to the optimum content (0.5%) with corresponding fibre aspect ratio of 125. The second part of this research, reports on the investigation on cement stabilised soil block. A local soil was stabilised chemically by cement. A better compressive strength at the dry state and after two hours of immersion in water was obtained with chemical stabilisation at cement content of 5%. Blocks stabilised with 5% cement content by weight of soil has a dry and wet compressive strength of 6.64 and 2.27MPa respectively, and dry density of 1910 kg/m3 at an optimal water content of 12% by weight of cement. The highly decreased compressive strength after two hours of immersion in water, even with higher cement content, indicated that appropriate building design that would prevent stabilised soil blocks from coming into direct contact with rainwater was important. A newly proposed concept of a plastic carton soil blocks as masonry units for low-cost environmentally friendly construction is proposed in the final part of the thesis. A test system was designed to perform rigorous and comprehensive measurements on seven types of soil block specimens encased in thermoplastic cartons. The cartons were similar to "ice cream tubs" of dimensions 165x60x120mm, thus making a building block/brick of reasonable handling size. Some of the test specimens also had soil mixed with palm or plastic fibres. Thermoplastic carton soil blocks without the addition of fibres as an enhancement were measured with a minimum compressive strength of 17.5MPa. Even so it should be noted that 17.5MPa is still a very reasonable strength and over half that of a typical concrete block. In the case of the fibre enhanced soil block, the compressive strength increased with increase in fibre content. With fibre addition of 1.5% (by weight), the compressive strength of the thermoplastic cartons increased by 28.5% and 38% respectively for palm and plastic fibres, over the plain thermoplastic carton soil block without fibres. For increase in fibres content from 0.75% to 1.5% (i.e. a doubling of fibre content) the compressive strength increased by only about 20% to 23%. Additionally, stiffness is also greatly improved. A finite element model was constructed for the thermoplastic carton soil block geometry and input files were generated for non-linear static analyses in MSC Patran. Very good agreement was achieved between the numerical predictions and experimentally measured results in both size and shape of the stress-strain graphs.

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Previous studies on Earthquake Risk Assessment (ERA) for Cyprus (Kythreoti, 2001) concluded that a new Peak Ground Acceleration (PGA) attenuation law needs to be derived based on local data and the vulnerability of the building stock needs to be fully re-examined. Field data from recent seismic activity became available and are used to derive a new PGA attenuation law. However, the damage data proved limited and analytical vulnerability curves were found to be necessary. Previous studies on analytical vulnerability underestimate damage from common brittle modes of failures. A variety of failure modes were simulated by using relatively simple element models, which were calibrated based on experimental data and expert judgment. A modified capacity-spectrum procedure was developed for the estimation of structural response and verified against time-history results. This procedure includes the bilinearisation of softening capacity curves so as to predict the response of structures deteriorating due to a variety of local brittle failure modes. A new damage index indicator was developed based on fundamental period shift and this \vas linked to damage limits. Key design parameters from capacity models were treated probabilistically and analytical vulnerability curves were derived for two building types and three design levels. A rapid increase in damage takes place well before the anticipated flexural failure threshold is observed in 'Pre' and 'Basic' design buildings. This occurs due to the dominance of brittle failure modes. The effect of the hazard spectrum on the vulnerability curves was found to be considerable. In the case of Cyprus, Type 2 spectra (EC-8, 2004) were found to simulate better the earthquake hazard potential. Annual insurance premium allocated for seismic risk in Cyprus is currently set at 0.060.08% of value and this appears to predict the overall risk accurately. However, the use of a single premium for all building types and the entire island leads to underestimation of seismic risk in Pre-seismic buildings. This underestimation is more profound in regions along the southwest coast of the island. The single most important issue for analytical vulnerability assessment is the definition of an appropriate structural model, which requires sophisticated modelling capabilities to simulate brittle failure modes and further work is recommended.

This study focuses on occupant acoustic comfort in domestic dwellings in England and asks how potential buyers and other interested parties can identify likely ‘quiet homes’ and likely ‘noisy homes’. To answer this question, the roles of building regulations, acoustic comfort classification schemes, building contractor and type of dwelling are investigated. The first of these investigations examines the effectiveness of building regulations at delivering homes built to standards that ensure satisfactory levels of occupant acoustic comfort. The investigation is undertaken through interviews with key personnel in Government and industry. The conclusions are that regulatory standards for sound transference between dwellings have changed little since they were introduced in 1965 (in force 1966) and continue today to remain too low and too poorly enforced to be relied upon to deliver adequate acoustic comfort levels for many occupants. The second focus of study concerns acoustic comfort rating schemes developed in a number of other countries. How these schemes work, their influence on improving acoustic comfort levels and their suitability for England are investigated through interviews with key people that developed them, practising acousticians and government employees. The key findings indicate that few people are aware of rating schemes in their respective countries and that similar number-based schemes are unlikely to be effective in England due to lack of government and industry interest. The third investigation aims to find out if different building contractors in England build their dwellings to different levels of acoustic comfort to those of their competitors. This qualitative investigation is carried out though an attitudinal survey of all major building contractors operating in England. Data is collected by letter written from the standpoint of a potential buyer. The investigation shows contractors only building to minimum regulatory standards and not competing with each other on levels of acoustic comfort. The fourth section of the study aims to found out occupant and buyer attitudes towards acoustic comfort. The quantitative survey collected data through an on line questionnaire. The findings reveal that acoustic comfort is a concern for many occupants, dwelling type is related to acoustic comfort and that prior to buying a home, acoustic performance is an important consideration for many purchasers. Overall this thesis concludes that after over forty years of regulating sound insulation, regulatory standards have not improved, remain poorly enforced, and are of a level too low to ensure satisfactory levels of acoustic comfort for many occupiers; and that measurement based acoustic comfort classification schemes are unsuitable for England, leaving type of dwelling as the only guide to acoustic comfort for consumers. Given the importance occupants and buyers place upon acoustic comfort this is a significant finding of practical value.

Worldwide interest in how to prevent the progressive collapse for tall and large buildings under exceptional loading conditions was heightened by the collapse of the twin towers at the World Trade. The performance of steel-framed structures subjected to fire loading is heavily reliant on the interaction between structural members such as columns, slabs and beams. The implicit assumption in fire engineering design is that bolted connections are able to maintain the structural integrity for a large and tall building under fire conditions. Unfortunately, evidence from the collapse of the World Trade Centre towers and full scale fire tests at the BRE Cardington Laboratory indicates that connections may be particularly vulnerable during both heating and cooling. Hence, this PhD research is focused on structural performance of simple steel connections under fire conditions, particularly the interaction mechanism between non-ductile and ductile components in a connection and connection failure mechanism in a steel-framed structure subjected to fire loading. The research involved experimental testing of simple steel connections and components (structural 8.8 bolts) at elevated temperatures. High temperature tests on structural bolts demonstrated two modes of failure at elevated temperatures: bolt breakage and thread stripping. In order to prevent the thread stripping in a connection, the manufacturing process of bolts and nuts has been investigated and the 'overtapping' of nut threads to accommodate the (zinc) coating layer for corrosion resistance has been indentified as a primary reason resulting in this premature failure between bolts and nuts. Experimental tests on endplate connections revealed the ductility of these connections to decrease at high temperatures, which might hinder the development of catenary actions in fire if plastic hinges are attempted to be formed within the connection zones. Component-based modelling and finite element simulation have been utilized for investigation of the performance of these connections. An improved component-based model has been developed which includes nonductile (brittle) components (bolts and welds) into a connection model with a reasonable assumption of their failure displacements, based on experimental tests. This model also features vertical components for consideration of shear response of these connections in fire. The component-based connection model has been used in a sub-frame structure and a parametric study demonstrates that a connection may fail due to a lack of rotational capacity (failure of bolts or welds) in a structure exposed to a fire. Therefore, partial depth endplate connections are recommended to be fireprotected to prevent the failure of these brittle components. Alternatively, ensuring the strength of brittle components (bolts and welds) is higher than that of other components in each bolt row is necessary to achieve the ductile failure mechanism of simple connections. Based on the experimental tests, component-based connection modelling and finite element simulation, recommendations to improve the robustness of simple steel connections in fire have been presented.

The research described in this thesis investigated the soil deformation due to the interaction of two neighbouring buildings founded on soft clay. The study involved small-scale Ig physical modelling in which mitigation of the interaction was studied by inserting a model sheet pile wall between two footings. The results were used to validate finite element analyses that were then extended to simulate a prototype of two buildings with raft foundations constructed on Singapore clay. In the physical models, two 100 mm wide strip footings were placed on a 200 mm thick bed of preconsolidated kaolin in a rigid chamber with a transparent front wall. Tests were conducted without a wall between the footings, with a 100 mm long floating wall, and with a vertically restrained (fixed) 100-mm long wall. The footings were loaded in tum and the second footing was only loaded after the consolidation, due to loading on the first footing or subsequent wall insertion, was completed. The soil and footing displacements were photographed through the transparent chamber wall and measured using a combination of Particle Image Velocimetry (PIV) and close range photogrammetry. A stiffer soil response was observed beneath the second footing than beneath the first. Some additional settlement of the first footing was induced by the loading on the second footing and this was not significantly mitigated by a floating wall. In contrast, with a fixed wall, the settlement of the footing was substantially reduced. Overall, the tilting in the tests with a floating wall was comparable to that in the tests without a wall. The tilting of the first footing, though not the second, was effectively mitigated when a fixed wall was used. Plane strain finite element analyses with the BRICK constitutive soil model were perfonned to simulate the physical models. In general, the observed behaviour patterns were well reproduced, although the finite element analyses tended to exaggerate the stiffness of the soil response under the second footing relative to that under the first when a wall was present. The simulated prototype comprised two 10m wide, 800 mm thick concrete rafts separated by 2 m resting on 40 m of clay. The analyses were similar to those conducted for the physical model simulations. In addition to modelling the effects of installing a floating or a fixed wall, parametric studies were undertaken to examine the influence of wall length and stiffness. A longer floating wall reduced the settlement of both footings due to loading on the second footing but even greater settlement mitigation was obtained with a fixed wall. The stiffness of the wall did not have a significant effect on the settlement mitigation except in the case of an unrealistically stiff fixed sheet pile. Without any wall, both footings tilted towards each other. The presence of a wall generally reduced tilting and the reduction increased with wall stiffness Keyword: closely-spaced footings, settlement, tilting, physical modelling, numerical modelling, finite element analysis, particle image velocimetry.

Earth was one of earliest materials used for construction of human shelters. In its raw state, it does not meet the basic physical properties required of a material for use in construction, i. e. compressive strength and durability (water resistance). The raw material can be stabilised to improve these properties through chemical, physical and mechanical methods. Chemical and physical methods involve mixing and compacting the earth with various materials to increase its compressive strength and reduce its propensity to shrink and swell. Mechanical methods of stabilisation involve only compaction of the raw material to produce blocks. Stabilised blocks have adequate compressive strength and durability for use in lowincome housing. They are also easy to handle, can be moulded to a variety of shapes and are suitable for use as structural blocks. The latest developments in the design of moulding machines means that stabilised blocks can be produced on-site at approximately half the cost of the next cheapest construction material (hollow concrete block). The most important consideration in the stabilisation process is the choice of material for mixing. The choice is based on three criteria: (i) composition of the earth, (ii) local availability of the stabilising material and (iii) cost of the stabilising material. For example, in terms of composition, earth with a high clay content, such as the samples used in this study from Sindh Province, Pakistan, was found unsuitable for construction purposes. This is because the clay minerals cause excessive shrinkage and expansion of the material. However, work conducted in this study found that the effects of clay can be mitigated by correcting particle size distribution and stabilisation. Specimens of stabilised material were produced to measure the affects of mixing various additives, including cement, lime, linseed oil, and calcium chloride, with earth. The key findings from research carried out on these specimens are: (a) Cement can not be used without correction of particle size distribution. (b) Previous research work has found lime to be the most effective stabiliser in terms of improving compressive strength. However, it was found that, in the case of the high clay content earth used in this study, cement provided better results. (c) In earth stabilised through correction of particle size distribution, linseed oil provided the most improvement to water resistance. (d) Calcium Chloride is not suitable for use as a stabiliser with earth containing a high proportion of clay minerals. This is because it reacts with the clay minerals to produce water. -(e) A comparative study of the cost and engineering benefits of various stabilised specimens showed that cement provides the greatest improvement to durability, but at the highest cost. Lime was found to be the best stabilising material for high clay content earth in terms of overall cost and engineering benefit. It provides adequate improvement to durability at low cost. Linseed oil was the cheapest stabilising material but, although greatly improving water resistance, it provided little improvement to compressive strength.

This thesis is an exploratory study into enteric complaints and respiratory ailments in early modern London between 1500 and 1720. These two diseases are closely associated with urban environments, especially domestic housing, and they killed significant numbers during the study period. Unlike the plague, these diseases were comparatively stable from year to year and this thesis argues that this was largely related to constant exposure to defective buildings. While research into the relationship between housing and health is problematic, mainly because the inadequacy of housing is invariably associated with other hardships, such as poor nutrition and hygiene, this thesis aims to overcome this obstacle by applying new tools borrowed from the modern discipline of building pathology. This offers a contextual definition of a building defect and identifies the fundamental requirements of healthful housing. Building pathology also draws attention to the interaction of the external environment with buildings; the climate of the study period imposed extreme demands on vulnerable buildings and their services. Although there were variations in the quality of buildings occupied by different sectors of the population, the demands of the climate were largely exogenous to economy and society. Applying building pathology analysis to early modern London identifies conditions that were conducive to the spread of enteric and respiratory diseases amongst the wealthy as well as the poor. The final part of the thesis considers the social epidemiology of enteric and respiratory diseases, that is locating them within communities, spatially and residentially defined and questions whether the study of economic or social groups in the context of these two specific diseases helps or hinders epidemiology.