The dynamic response of highway bridges is a topic that has been thoroughly researched over many years. However, understanding of how the dynamic response of bridges is affected by the performance of their bearings over an extended period of time is, at present, not clearly defined. Although health monitoring of bridge structures is relatively advanced, the scope for further research is wide. The study presented in this thesis contains research on plate structures; ranging from a simple Euler-Bernoulli method to determine natural frequencies; modal analysis of a plate structure in the laboratory; FEA of the plate structure; modal analysis on a full-scale structure subjected to vehicle loading; and FEA of a simplified model representing the full-scale structure. A combination of these methods has allowed the conclusions presented herein to be drawn with respect to the effects of support degradation, and the consequent effect on structural performance. In the laboratory, modal analysis of a small-scale, thin rectangular plate of Perspex' has been completed. A series of boundary conditions have been investigated through altering the support offered to the plate by a series of springs, each with a different stiffness, to simulate bearings with different stiffnesses. Vibrations of varying frequency have also been forced upon the plate, and its response recorded. Displacement values provided the clearest indication of the effect of bearing stiffness, with the least stiff spring resulting in the largest displacement. Alteration of support stiffness in the model can have a marked effect on the resonant frequency of the plate (approx. 23 % frequency change between spring 1 (1.22 Nmm 1) and 5 (15.62 Nmm 1)). Full-scale testing on a highway bridge at Berwick-upon-Tweed on the Al, over the River Tweed, was completed in May 2005. These data form the baseline for future dynamic testing and condition monitoring of the structure. To describe the dynamic properties of the structure, the force generated by each type of vehicle traversing the structure was determined using instrumentation already in place on the bridge. Statistics drawn from the data are presented, which indicate that the bearings are functioning as expected, but are subjected to forces of a much larger magnitude due to overloaded HGVs than in current design specifications. Larger HGVs made up a small percentage of overall vehicles recorded, but contribute a much higher proportion of damage caused to the bridge. Displacement and frequency were both valid measures of bearing performance and therefore state of degradation. The method is offered as a condition monitoring test for bridges and their bearings.

No description available.

Network analysis techniques have been used for planning purposes in the construction industry for over a decade. They have been used with various degrees of success by the client to control the progress of his job; by the architect (or consultant) to plan the design phase of the project; and finally by the contractor to prepare his pre-tender and contract programmes. This study is concerned about the factors which contribute to higher success in the use of network analysis techniques in contracting organizations.

Mitigation of progressive collapse after an initial failure has become a primary concern of engineers in recent years. Often alternative load paths are sought to redistribute load from the damaged area. It has been recognised for some time that the omission of compressive membrane action (CMA), also termed ‘arching action’, can lead to a significant underestimation of load capacity. An investigation has been conducted to ascertain whether the additional load carrying capacity from CMA can provide an inherent alternative load path to aid robustness. A series of scaled specimens with industry standard detailing have been designed for an experimental investigation. Reinforced concrete elements were modelled in the double span scenario once an intermediate column has been removed. The test rig used allows the central support to be removed followed by the application of a point load applied at midspan; the system is determinate including measurement of the horizontal reaction. Subsequent to the flexural response two modes of membrane action are induced, initially compressive until tensile membrane extends load capacity at high values of deflection. The response during the latter tensile phase is outside the scope of this research. Comparisons of experimental data with analytical methods inclusive of CMA have demonstrated that whilst conservative the method by Merola (2009) provides a reasonable prediction. This method has been utilised in a study of a series of flat slab structures with a range of column spacings. The inherent restraint stiffness provided by the surrounding slab and frame has been quantified using FEA and has allowed for the extent to which CMA can improve the robustness of a structure to be determined.

In the year 1755, the lower part of the city of Lisbon was hit by a severe earthquake. Immediately following the earthquake a complex reconstruction process began, which introduced new urban, architectural and constructional concepts. This resulted in the creation of new innovative rentable buildings termed the Pombaline rentable buildings, after the Marquis of Pombal who directed their construction. This thesis comprises a wide ranging and detailed study of these buildings. At the beginning of this work, in Chapter I, "The Pombaline rentable building" is placed in its historical context. The origins of the old city are described and its historical development within Portugal. The results and consequences of the 1755 earthquake are outlined, and the subsequent process of reconstruction is described. All immediate measures, decrees, and proposals for the reconstruction of the city, plus Manuel da Maia's Dissertations, are carefully compared and analysed, as are the various plans proposed for the reconstruction. The preceding periods of Portuguese Architecture are studied to identify possible origins for the architecture of the Pombaline rentable buildings. Also a clear definition of the Pombaline Rentable building and the limits of the genuine Pombaline area are established. In Chapter II the general methodology used in the research is described, which includes a survey of 315 buildings and a documentary search for material relating to the construction of the buildings. In Chapter III an analysis is made of the general external and internal architectural characteristics of the rentable buildings. An extensive search for original drawings, produced drawings only of the elevations of the main streets. These are carefully analysed and compared with existing buildings and a classification system is developed. A complete survey by the author of the buildings' interiors, for which no documentary information exists, reveals a great complexity and variety of interior plans. To achieve a systematic classification of the interiors particular aspects are analysed including, the types of stairs, the organization of the interior spaces, the building location and the finishing details. Chapter IV describes some of the technical innovations shown by the rentable buildings, particularly those referring to earthquake resistance in construction and to prefabrication. During the survey of plans and elevations the Author identifies evidence for the existence of prefabrication, in terms of sizes of components, tolerances and detailing. This evidence is supported indirectly by documentary material although the extent of documentation is very limited. vii Possible evidence for an evolutionary development in the internal plan and design of the buildings based upon the position of stairs in the buildings is presented in Chapter V. An attempt is made to relate this classification to the dates of construction of the different buildings. This is achieved by an analysis of previous tax records which enable numbers of buildings constructed on different streets at different periods to be determined. Based on this analysis the evidence for an evolutionary development is discussed. In Chapter VI the Pombaline rentable buildings of Lisbon are compared with other contemporary developments at Porto Cövo, Vila Real and Manique do Intendente in order to assess the influence of the Pombaline development, both in terms of the architecture and the construction processes, on other construction projects outside Lisbon. Chapter VII discusses the principal findings of the research and their importance in the context of Portuguese architecture.

The aim of this research was to investigate the thermal performance of Double skin facades (DSFs) for office buildings in Amman. Special attention was given to the role of cavity-integrated shading slats. The study was conducted through a parametric study concerning configuration and design parameters of both DSF’s cavity and shading slats, in addition to boundary conditions. For the purpose of this study, a CFD-Fluent model was developed and validated. Besides, a new method for more accurate representation of solar radiation (as boundary conditions) was developed. Both RNG k-ε and SST k-ω turbulence models were used. The Discrete ordinates (DO) radiation model with non-gray option was selected for modelling of radiation heat transfer. Simulations confirmed that both the width of the cavity and the size and arrangement of openings would have a significant impact on overall performance of the system. The aspect ratio (H/W) of the cavity would further impact its operation, which could contribute to 77% and 26% increase in ventilation and temperature for inner glass surfaces, respectively, of a simple cavity. In addition, among other design parameters, the size and surface emissivity of integrated slats would have the largest influence on the natural ventilation rate in the cavity. The inner glass surface temperature is mainly influenced by the inclination angle and position of these slats in addition to the internal and external environmental conditions. The influence of these slats is also dependent on the aspect ratio of the cavity. Detailed design of these slats would play a further role, together with the boundary conditions (incidence angle) and other design parameters of the cavity (H/W aspect ratio). In Amman, DSFs were shown to have a good performance during heating seasons, as they would enable indoor thermal comfort and ventilation requirements to be met by passive means. During cooling seasons, DSFs with integrated slats would also be able to reduce total solar heat gains if sufficient ventilation could be provided for its cavity. However, artificial cooling is still required for such a hot climate. Controlling the cavity openings is highly recommended for both scenarios. It is recommended that the cavity width is at least 0.6m, the glass transmittance is about 0.8, the size for integrated slat is 20% of the cavity width, and the optimum surface emissivity of the slats is about 0.2. Slats should preferably be placed at mid of cavity or be adjustably according to the seasonal requirements. Optimum inclination angles for slats were found to be 45° degrees and 30° degrees for summer and winter, respectively. General recommendations and design guidelines were provided.

A study has been conducted into improving construction design through the application of the lean thinking paradigm. Its objective was to identify the issues relating to design efficiency and how a lean thinking approach might address these issues. The investigation consisted of examining work already undertaken in the field by other researchers"to identify the state of the art. The change order request system was examined to gain first insights into waste in construction design, and to gauge the size of the opportunity for the application of lean thinking. An Electronic Data Gathering Tool (EDGT) was then developed to allow further exploration of the design decision making process at the system / sub-system level. The EDGT was used on three live construction projects. From the data recorded a design planning tool, Design Decision Planner (DDP), was created to help improve control of the design process and lead to a more standardised approach to construction design. Standardising the approach to product development is an important component of lean thinking. The main recommendations for making construction design lean are: Use DDP to plan and improve control of the design decision making process, assign design responsibility and to make the process more transparent. 2. Measuring progress against planned design is a useful process metric. 3. Improve the designer's cost and programme visibility when choosing between design options. 4. Redefine the role of the quantity surveyor from cost controller to value for money assessor. The role needs to be better integrated into the design process to reach its full potential. 5. Need to develop more rigorous methods of assessing the buildability of design options. This problem could be eased in the short-term by incorporating construction professionals into the early design phases. 6. Designers need to use more process reason drivers when choosing between design options, not just functional criteria. 7. The change order request system could be redesigned to identify the root causes of contract issue design changes and, hence, improve the design decision making process.

No description available.

This research constructs and tests a model of the organisation of building projects for maximum benefit to clients. The model is developed from systems theory, independently of conventional organisational assumptions. It is based upon the premise that the process to be managed must be identified before organisational structures can be designed and it recognises the influence of environmental forces upon projects. The model proposes that the process of building provision consists of sub-systems created by decision points and identifies the interdependency and hence the differentiation within and between the subsystems. The major propositions of the model are that; a) there should be a match of differentiation and integrative effort, b) the operating and managing systems should be differentiated, c) the managing system itself should be undifferentiated and, d) the client and process of building provision should be integrated. The model was tested against three commercial buildings for private clients. Data is presented from interviews and other sources and is interpreted using Linear Responsibility Analysis, which was adapted and developed in this research. The testing method examines the overall compatibility of the model and the test projects, and also identifies the causes of deficiencies in the outcomes of the projects and whether they can be explained by divergence of the projects from the model. The model was found to be valid for the type of project used in the tests. It provides a theoretical framework against which the effectiveness of organisation structures for the management of building projects can be predicted and which can be used for the design of such structures. It is suggested that Linear Responsibility Analysis provides a useful tool for organisation analysis and design. Finally, implications of the results for the organisation of building projects in practice are discussed.

The house-building industry should evolve towards the production of dwellings of higher quality standards. Minimum standards are required to ensure that all new homes will be structurally sound, comfortable and have a long and reliable life. The notion of quality does not just concern the dwelling itself, but also the immediate and wider environment, namely the proximity of schools, shopping and leisure areas (theatres, cinemas, sport centres, playgrounds), accessibility (roads, railway lines, underground, buses) and views. To achieve higher quality standards better design quality evaluation and inspection schemes are needed In this thesis a new approach for the evaluation of the quality of dwelling designs named QDF (Quality Dwelling Framework) is proposed. In order to develop QDF a parallel between the form of a dwelling and the form of a human body is drawn. This is justified by the fact that the human body is a most sophisticated and highly developed form. The methodology behind QDF is the systems approach. In QDF, a dwelling is organised, in a hierarchical way, into systems, subsystems and components. Each of the elements in the hierarchy is both a system and apart of a larger system, i. e. a holon. Holons are modelled as software objects, in the sense of object-oriented programming. QDF is an important contribution in the direction of raising dwelling quality standards (quality is used here in the sense of fitness for purpose). It provides a comprehensive framework to implement and develop different quality evaluation methods, adapted to different countries and cultures. No specific parameters are imposed for quality evaluation of each system, and so dWerent quality evaluation schemes may be implemented The parameters are dependent on several factors, namely: the climate, the habits of the users and the development of the construction industry in the relevant country. QDF is a generic framework, within which different evaluation methods can be implemented and adapted to different situations. It has been designed so that it can help all parties involved in the residential building industry, namely users, builders, architects, engineers, property developers, bankers, building societies, state agents and politicians, to agree upon quality standards tuned to the national or regional realities. A strategy for the corroboration of QDF has been proposed, based on Popper's philosophy of scientific knowledge and on an extension of this theory proposed by Blockley in the context of risk analysis. QDF can only achieve a high degree of corroboration by testing it in practice in the long term, i. e. users will use the system, make decisions, live in a house; and then provide feedback as to whether the evaluation turned out to be dependable or true (i. e. decisions correspond with the facts). The process of evaluating QDF has been initiated by using a prototype system, developed in the programming environment KAPPA, to evaluate different dwelling designs as well as different alternative solutions for the same dwelling design. QDF is compared with product models of buildings, namely the BATAS product model and the AEC building systems model. The QDF prototype system implements the quality evaluation for a thermal system (the metrics have been developed by Paiva and are based in the Portuguese thermal regulations), an electrical system (the metrics used are defined in the Qualitel method) and a close environment system (the metrics used are defined in the SEL method). The development and use of the prototype indicates that the complexity of modelling a dwelling in a comprehensive way calls for advanced computer techniques which provide high storage capacity and fast processing. As QDF is a naturally parallel system, this could be achieved in future by using parallel computer architectures, which are adequate for the developed model, based on the object-oriented paradigm.