<p>The purpose of this study is to determine if Virtual Reality safety training is more effective at teaching fall protection safety than traditional methods of instruction. A literature review of previous research was conducted and a theoretical framework and methodology was developed to test the two groups for this study. The research design is a difference-in-differences method comparing the pre-test and post-test scores of the participants of each group. There will be other small pieces of analysis that will be done to further understand the results of the data collection. The data will be analyzed and interpreted to better understand how the research question was answered in comparison to previous work and the theoretical framework. Finally, other questions that arose during the process will be addressed and future areas for more research will be defined.</p>

Cold formed steel (CFS) sigma sections are commonly used as purlins in the construction of modern industrial and residential buildings due to their excellent strength-to-weight ratio. This thesis reports investigations on the structural behaviour of CFS sigma purlins in three different parts of modern roof systems. In the first investigation, the pre-buckling, buckling, post-buckling and post-failure behaviour of continuous CFS sigma purlins near internal supports was studied by experimental and numerical methods. In the second investigation, the moment-rotation response as well as the moment resistance of the sleeve connection of sigma purlins was studied by laboratory tests. Engineering models were developed to predict the behaviour of this connection and a good correlation was observed with the experimental data. In the third investigation, the flexural stiffness and moment resistance of CFS sigma purlins fastened to roof sheeting with large screw spacing was studied experimentally. The purlin-sheeting assemblies were subjected to both downward and uplift loadings, from which different behavioural aspects such as flexural stiffness, failure modes and ultimate load were examined. Test results are utilized to develop design proposals for sigma purlins that codes or standards have not yet covered.

Lessons learnt from the construction industry have proved that knowledge management (KM) can enhance construction projects successfully. The existing KM models and tools may have some problems, which cannot be used efficiently and effectively. This research aims to develop a new KM model that overcomes such problems and provides an effective way for managing knowledge in the construction industry. An extensive review and analysis of KM models has been carried out and a KM model was developed to fill the gaps of previous KM models. Interviews with KM practitioners and a questionnaire survey have been conducted to enhance the KM model. A final KM model has been set to provide an effective solution for successful implementation and application of KM in construction projects. Two case studies in the construction industry have been carried out to evaluate the applicability and validity of the proposed KM model and how it can be used to improve existing KM systems. The results indicated that the proposed model can effectively facilitate the implementation and application of KM in the construction organisations. Recommendations are given to improve the future implementation and application of KM in construction projects.

The supply of adequate and affordable houses is still a big challenge in many developing countries. Governments have sought to use different housing strategies, such as public private partnerships (PPPs), to solve these urban housing problems, but with limited success. The aim of this study is, firstly, to examine the challenges affecting the delivery of HPPP projects in developing countries and, secondly, to propose a PPP conceptual model to address the identified challenges. A mixed-methods approach was used to collect data from various stakeholders involved with housing public private partnership (HPPP) projects. Purposive sampling was used to select the targeted respondents. The quantitative data were analysed through the Statistical Package for the Social Sciences (SPSS 22.0) whereas the qualitative data were analysed by content analysis. This study identified several challenges hindering the success of HPPP projects with the highest ranked challenge found to be: inadequate PPP skills and knowledge. Results demonstrate that PPP can be adopted as an alternative approach; however; the identified challenges need to be addressed for a successful outcome to be achieved. The key contributions to knowledge include: bridging the literature gap as this study is the first that identifies and ranks the HPPP challenges within the developing country context. Additionally, a conceptual model has been developed by adopting (and modifying as appropriate) success factors from international best practice. It is anticipated that the proposed conceptual model, validated by PPP experts, will provide a valuable road map for the successful delivery of HPPP projects in developing countries.

This thesis is about late medieval carpenters, their techniques and their art, and about the structure that became the fusion of their technical virtuosity and artistic creativity: the hammer-beam roof. The structural nature and origin of the hammer-beam roof is discussed, and it is argued that, although invented in the late thirteenth century, during the fourteenth century the hammer-beam roof became a developmental dead-end. In the early fifteenth century the hammer-beam roof suddenly blossomed into hundreds of structures of great technical proficiency and aesthetic acumen. The thesis assesses the role of the hammer-beam roof of Westminster Hall as the catalyst to such renewed enthusiasm. This structure is analysed and discussed in detail. Its place in the milieu of late medieval architecture is assessed, and its influence evaluated. That influence took effect mainly in East Anglia. Thus, early fifteenth-century trends in hammer-beam carpentry in the region are isolated and analysed. A typology of is created, from which arise surprising conclusions regarding the differing priorities late-medieval carpenters ascribed to structure, form and ornament. A chapter is also devoted to a critical review of literature pertaining to the topic.

When used as secondary roof purlins, cold-formed steel (CFS) sections are often attached to trapezoidal sheets through self-drilling screws to form a complete roofing system. The load application points are often eccentric to the shear centre, and thus inevitably generate a torsional moment that will induce twisting and/or warping deformations in addition to bending deflection. The connections between purlin and roof sheeting provide a restraining effect on purlin members by preventing such lateral and twisting movements, and hence have a beneficial effect on the load-carrying capacity. In this thesis the interactional behaviour of CFS purlin-sheeting system have been investigated through the following steps: (1) A F-test is carried out to measure the rotational stiffness at the connections, an engineering-orientated model is developed for quantifying the rotational stiffness regardless to purlin and sheet geometry and loading directions; (2) A set of loading tests on Z- and Σ- roof system are conducted to investigate the impact of rotational stiffness on the overall structural performance, load-carrying capacity and buckling behaviour of the system; (3) Finite element simulations of the existing tests are carried out and successfully validated; (4) Numerical parametric studies are established to study other factors that could affect the rotational stiffness.

Beam-column (BC) joints play an important role in the seismic performance of moment-resisting reinforced concrete (RC) frame structures. Without adequate joint shear reinforcement, BC joints can be the most vulnerable elements during an earthquake. Several techniques for improving the seismic performance of BC joints have been proposed, but they have been criticised for being labour-intensive and/or susceptible to premature debonding. This research explores the application of the deep embedment technique for strengthening a shear-deficient beam-column joint. Two approaches, experimental and finite element (FE) study were conducted. The experiment contained the tests of seven exterior RC BC joints under constant column axial load and a reverse cyclic load at the beam end. Variables considered during the experiments were the material type and embedded reinforcement ratio. The FE study included the modelling of the tested specimens using ABAQUS and parametric study to asses the effect of column axial load, concrete compressive strength and embedded bar size on joint shear strength. The experimental results showed the strengthened specimens had superior global and local behaviour compared to the control one. In addition, the maximum joint shear strength also changes linearly with the variation of the concrete strength, column axial load and embedded bar size.

Initially, two experimental programmes studying the structural behaviour of stainless steel beam-to-open column joints and beam-to-tubular column joints under static loads are reported in detail. The joint configurations tested include flush and extended end plate connections, top and seat cleat connections and top, seat and web cleat connections. The full moment-rotation characteristics are reported in detail. It is observed that the connections displayed excellent ductility, superior than that of equivalent carbon steel connections, and attained loads much higher than the ones predicted by design standards for carbon steel joints. Nonlinear FE models have been developed and validated against the experimental results. The FE models are shown to accurately replicate the experimentally determined, initial stiffness, ultimate resistance, overall moment-rotation response and observed failure modes. In addition, a comprehensive parametric study is conducted. The design rules for stainless steel connections, which are based on the specifications of EN 1993-1-8 for carbon steel joints, are reviewed and are found to be overly conservative in terms of strength and inaccurate in terms of stiffness thus necessitating the development of novel design guidance in line with the observed structural response. Hence, simplified mechanical models in line with the observed response are developed.

The building construction industry is growing all over the world and considered as a labour-intensive industry. It is associated with significant safety risks and losses resulting from major accidents. These critical safety risks are largely due to lack of awareness, which causes poor performance. Furthermore, in construction management projects, risk assessment tools are still widely employed by adopting two traditional parameters, severity of consequence (SC) and probability of occurrence (PO), to analyse the safety risk level. It is not clear, however, whether this analysis can evaluate the safety risk magnitude appropriately, which necessitates the introduction of another parameter, probability of consequence (PC), to improve the risk evaluation. The fuzzy reasoning technique (FRT) is useful for quantifying and dealing effectively with the lack of certainty related to the domain of building construction projects. PC was incorporated into the model which allows safety risks to be assessed correctly. Furthermore, the modified fuzzy analytical hierarchy process (MFAHP) and fuzzy technique for order preference by similarity to ideal solution (FTOPSIS) methods are integrated into a new construction safety risks model for the evaluation of important safety risks. Four specific case studies are employed to illustrate the applicability and performance of the proposed model.

Structural members of reinforced concrete (R/C) buildings designed according to older, less stringent seismic codes are often vulnerable to shear or flexure-shear failure followed by axial failure. Thus, such substandard R/C structures are susceptible to vertical collapse, which pertains to the exceedance of vertical resistance of columns and connecting beams and can lead to the whole structure – or a substantial part of it – undergoing collapse. The largest database of shear and flexure-shear critical R/C columns cycled well beyond the onset of shear failure and/or up to the onset of axial failure is compiled and empirical relationships are developed for key parameters affecting the response of such members after the initiation of shear failure. A novel shear hysteresis model is proposed employing these relationships, based on experimental observations that deformations after the onset of shear failure tend to concentrate in a specific member region. A computationally efficient finite element model of the member-type is proposed, using the above shear hysteretic model and combining it with displacements arising from flexural and bond-slip deformations to get the full lateral force-lateral displacement response. It accounts for the interaction between flexural and shear deformations inside the potential plastic hinges, the distribution of flexural and shear flexibility along the element, as well as the location and extent of post-peak shear damage, without relying on assumptions about the bending moment distribution and avoiding shortcomings of previous beam-column models pertinent to numerical localisation. Thus, the full-range hysteretic response of substandard R/C elements can be predicted up to the onset of axial failure subsequent to shear failure with or without prior flexural yielding, while simultaneously accounting for potential flexural and anchorage failure modes. The proposed model is implemented in a finite element structural analysis software and its predictive capabilities are verified against quasi-static cyclic and shake-table test results of column and frame specimens. The model is shown to be sufficiently accurate not only in terms of total response, but more crucially in terms of individual deformation components. Overall, it is believed that the accuracy, versatility and simplicity of this model make it a valuable tool in seismic analysis of complex substandard R/C buildings. An experimental investigation of shear and flexure-shear critical R/C elements is carried out with the aim of independently validating the beam-column model. Furthermore, an opportunity is provided to verify the model’s underlying assumptions, which is of paramount importance for the reliability of its analytical predictions. The experiments were designed in such a manner as to investigate the effect of vertical load redistribution from axially failing members on the lateral post-peak response of neighbouring columns.