This thesis covers the study of modelling techniques and optimisation methods used to help low-energy building design.

This thesis tests the hypothesis that the ventilation systems installed in UK dwellings, constructed in 2003/04, are adequate to control indoor pollutants and provide acceptable indoor air quality. The debate regarding recommended levels of airtightness for UK dwellings, and the question 'can a limit be established', is also addressed. The theoretical requirements to achieve health, comfort and energy efficiency within dwellings, is reviewed and how the current strategy of 'Build tight and ventilate right' is being achieved in practise compared to theory. The thesis examines in detail the evidence that, in practice we are ventilating right, and explores the concept being applied: 'to control ventilation heat loss, by reducing uncontrollable air infiltration, at the same time as providing adequate indoor air quality by controllable background ventilation'. This study revisits this concept and questions the validity of building tighter buildings only to add 'designer holes' in the name of energy efficiency. The thesis examines the installed performance of the ventilation systems' component parts, as found in UK dwellings. In addition to questionnaires and interviews with residents, the ventilation system 'in-situ' is inspected and tests carried out. The operation of peoples' window habits is also monitored by visual inspection over a one year period. Laboratory measurements of the ventilation system are taken for both ideal installations, and as found in reality on site. The results of this empirical data are then entered into computer models representative of the dwellings, to discover the impact of how buildings really perform. Empirical evidence suggests that occupants control their windows predominantly in response to external temperatures. Installed extract fans can provide as little as 30% of the Building Regulation requirements when manufacturers data suggests that they should comply. This is primarily due to the poor installation of the fan into a real building system. Airflow through background (trickle) ventilators was also found to be compromised by 38%, due to inferior routing of the slot through the window system. Anti-weathering techniques applied by the window manufacturers further inhibited the air flow through the ventilators by as much as 46% compared to the ventilator manufacturers' performance data. The results from the software models indicated that tightly constructed dwellings would provide a reduction in ventilation heat loss, but at the expense of IAQ if ventilation systems were not performing as designed or used as intended. No evidence from either academic studies or from manufactures could be found which measured the installed performance of domestic ventilation systems, in particular the performance of the component parts used to form the basis of a natural ventilation system generally found in most UK dwellings. This thesis provides much needed information on the "real" performance of ventilation systems as "installed" in the UK. The study found there was a need for the installation and performance of ventilation systems to be tested 'in-situ'. There would appear to be a case to call for a legislative regime to inspect and if possible test the ventilation systems of new dwellings as they are completed.

No description available.

Construction projects frequently overrun and finish over budget; in part due to the lack of control that construction practitioners have over the construction schedule at a process level. Planning methods such as CPM are not of sufficient detail to allow a practitioner to plan a process to maximise its performance. Thus the aim of this research was to develop a practical, computer-based model to enable practitioners to plan projects at a process level and hence improve their projects. This research has focused upon a specific type of process - those that are stochastic and cyclical. Such processes are difficult to predict and hence control, and they are widespread throughout construction projects. Examples are crane operations, formwork erection and scaffold erection. Initially, a focus was placed on the ready-mixed concrete (RMC) supply process. A discrete event simulation (DES) model of this process was developed and validated, based upon real project data. This model could not provide accurate estimates of the process due to the requirement that a user define the probability distributions that represent the process. This is a complex requirement for a practitioner, the issue became known as the complexity problem and a solution was sought using case-based reasoning (CBR). CBR provides solutions to new problems using knowledge from past ones - exactly what a practitioner was doing in the above simulation model. CBR was shown to be capable of solving the complexity problem. A hybrid model, <i>CBRSim, </i>was formed to fulfil the original aim of this thesis. <i>CBRSim </i>works by: CBR selecting probability distributions (based on user input) that are used in a DES model to accurately recreate the process. CBRSim was validated and modelled the process to within +/- 3% accuracy. <i>CBRSim </i>was then applied to another stochastic and cyclical construction process: earthmoving. <i>CBRSim </i>was found to be more accurate in estimating earthmoving productivity than RMC supply, thus providing an indication of a generic modelling capability.

Hydration pressure generated as the anhydrous salt (thenardite) hydrates to form the decahydrate (mirabilite) was originally thought to be responsible for the sever damage to stone buildings and monuments infected with this salt. New results based on an in situ temperature controlled dynamic XRD study show for the first time, the reformation of mirabilite during cooling and provides an insight into the supersaturation attainable in this experiment before reprecipitation of mirabilite. Also of practical interest is the behaviour of sodium sulphate in the presence of other commonly occurring cations. Ca was used for this study due to the wide spread occurrence of gypsum in relation to stone damage.  A synchrotron experiment conducted on beam line 16.4 at Daresbury Laboratory, shows for the first time the precipitation and dissolution of eugsterite (Na₄Ca(SO₄)₃.2H₂O) from the starting materials of solid mirabilite and gypsum, cycled up and down in temperature using a glycol cold cell in the path of the beam. Crystallisation by evaporation was also used as another method of investigating the effect of calcium on the crystallisation of sodium sulphate at a single temperature above the mirabilite-thenardite transition temperature of 32.4°C. A definite relationship was found to exist between the amount of calcium in solution, the formation of phase III and the eventual formation of eugsterite. Part of the Skara Brae settlement in Orkney, a site of cultural importance and showing signs of extreme weathering was investigated for sings of salt decay. Many different methods, including water transport analysis, were used to investigate the samples from the site itself and representative samples taken from close to the site to assess the relative important of the decay mechanisms found to exist. The final experimental section of this thesis deals with the analysis of water transport through three commonly used building materials. Characterisation of the materials using a variety of methods is given to explain their strong variation in the water transport properties.

In June 1990 a fire occurred in a large contractors' hut on the first floor of a 14 storey steel framed building in the Broadgate development. Despite large deflections the structure behaved well and there was no collapse of any of the beams, columns or floors. A major investigation was undertaken of the fire and the structural performance. It was concluded that the building behaved as a framework of elements though designed as a collection of isolated elements. The connections were able to accommodate large deformations and forces without failure. Hence when the framework acts as a total entity structural stability is significantly improved. The investigation recommended that more research and analysis was required to study the characteristics of frame action in fires. This thesis details a study of the behaviour of multi-storey frames at elevated temperatures. A series of pairs of five storey two bay plane steel frames were designed to demonstrate restrained column collapse behaviour and column collapse due to hinges forming in the restraining beams at ambient temperatures. In a pair, both frames collapse under the same applied load but each frame displays one of the collapse mechanisms. This thesis chronicles the construction of the frames and the tests carried out at ambient temperatures and under various heating configurations. A non-linear elastic frame analysis was developed based on the slope deflection method. The reduction in flexural stiffness of the critical column due to bending plasticity is modelled with a non-linear spring. This analysis is used to predict the collapse load and collapse state of each frame tested. Comparisons are made with predictions from the EC3 simple column design method. The non-linear elastic frame analysis is also used to investigate the frame responses which occur due to the presence of elevated temperatures.

Tabulated accounts form the framework for this investigation into the building craftsmen of sixteenth and seventeenth century Worcester and the buildings they produced. Augmented by other research material they have allowed the organisation and financial basis of the building trade to be assessed and the family background and social status of the craftsmen to be examined. The costs and sources of the materials used have also been evaluated and the prices of timber and brick compared during the crucial period when brick was supplanting timber as an economic material. Building methods have also been reviewed. A central aspect of the study is the transformation of the mediaeval house and the effect on the houses of Worcester. For this, local probate records have been analysed to provide material relating to the decline of the hall and the spread of glass windows and masonry chimneys. The shape of the house and the use of space have also been considered. Physical and visual material, standing buildings and photographs and pictures have played a vital part in this study and the interaction between buildings and documentary data is fundamental to the thesis. 81,500 words.

No description available.

Due to an increase in impermeable hard surfaces, urbanization has led to the deterioration of urban watercourses and increased the quantity of stormwater runoff. It may be argued that the current norm of impermeable roofs represents a wasted opportunity. Green roofs have the potential to replace some of the hydrological characteristics of natural catchments that are normally lost as a consequence of urbanization and the removal of vegetation. The overall aim of this study was to develop a generic green roof rainfall runoff response model capable of predicting the temporal variations within any configuration of green roof in response to an arbitrary rainfall input. It was recognized that the preliminary investigations has led to the identification of a subset of processes/parameters for a green roof which warranted more detailed investigation. In this case the substrate moisture holding capacity and the losses due to evapotranspiration were identified as key controlling variables to be identified. To simulate the function of stormwater drainage, a direct observation of the system's behaviour is required. Hence, an established 'typical' small scale green roof (1.0 in x 3.0 m) on the roof of Sheffield University has been monitored with the intention to relate both retention and detention with fundamental, measurable, physical properties of the system. A continuous long time-series of data, in the period of 29 months, from the test rig was analysed and interpreted. Laboratory analyses on physical properties and evaporation of the substrates were undertaken and relationships between measureable physical properties and model parameter values were identified. The empirical (requiring site-specific calibration using monitored data) conceptual model now has been developed into a physically-based model. Although the model still needs to be refined, independent physically-based methods have been identified for defining two key parameters (evapotranspiration (ET) and the maximum moisture-holding capacity (WC,,, a,, )). ET can be estimated using a modified form of Thornthwaite's equation, and WC.., may be determined by physical laboratory assessment of the substrate. The proposed hydrological model has been shown to reproduce monitored data, both during a storm event, and over a longer continuous simulation period.

This thesis sets out to analyse the growth of the building regulations in this country during their most formative years in the nineteenth and early twentieth centuries. The originality of the study is that it is the first complete history of the regulations. The study concentrates upon the regulations which relate primarily to building design and construction. Particular emphasis is placed on the national trend, as exemplified by the Model Building By-laws in conjunction with the influential role played by the London Building Acts. Reference is also made, by way of illumination, to the content and implementation of various local building acts and by-laws. The pressures which affected the building regulations - from society from more complex buildings, new building types and new materials for example - are all duly assessed. As a result the work reflects upon a number of lesser known facets of the Victorian building world. The material used has included the Acts and By-laws themselves, commentaries and opinions contained in contemporary journals papers and reports, as well as the discussion in Parliamentary debate and at the meetings of the Professional bodies. The first three chapters describe i three separate routes into the subject : the sanitary reform movements the legislation in London, and provincial activities. The sequence of chapters then proceeds chronologically, alternating between London and the Provinces highlighting the principal London regulations of 18449 1855 and 1894 and the Model By-laws of 18581 1877 and 1890. The intervening amending Acts and modifications to the By-laws are also included. The principal technical details are collated, tabulated and connecting links established between them. The study provides, in addition to the detailed documentation and historical interpretation evidence of the factors which have determined the form of our present building regulations.