Browsing Engineering & Technology by Authors
Contractors’ selection criteria for sustainable infrastructure delivery in NigeriaCeranic, Boris; Dean, Angela; Arowosafe, Oluwumi I. (University of Derby, 2020)The research reported in this study developed and validated a framework for the pre-evaluation of contractors for sustainable infrastructure projects through Public-Private Partnership (PPP) in Nigeria. The proposed framework uses the Analytic Network Process (ANP) to select contractors for build-operate-transfer (BOT) contractors. Theoretically grounded on a system theory, a sustainable infrastructure delivery (SID) model is developed in this research. One of its important features is the ability to solve complex decision problems, typical of a decision-making process that involves selection of contractors for PPP projects. At the deductive phase of the proposed model is the integration of the ANP (multi-criteria decision-making technique) for data synthesis. An extensive literature review was conducted with regard to selection criteria for contractors. Furthermore, a web-based questionnaire survey was undertaken, aimed at capturing the perception of the Nigerian construction professionals regarding the importance of these criteria for pre-evaluation of contractors for public infrastructure procurement. A total of 143 questionnaires was received and their feedbacks were analysed with the IBM SPSS statistical package. The findings revealed a broad range of 55 relevant criteria that were linked to sustainable contractor selection. Through the application of factor analysis, the number of the criteria was reduced to 16, after multicollinearity issues in the data set had been resolved. The 16 factors were modelled to pairwise comparison matrices, transforming decision making process from linear to a systemic approach. A purposeful sampling methodology was then applied for the selection of decision-making panel (DM), who completed the pairwise comparison survey. The survey results were synthesised by ANP. The final solution derived order of significance of the two categories of contractors- multinational construction corporations (MCC) and local construction contractors (LCC) in respect to the delivery of a sustainable infrastructure. Sensitivity analysis of the research findings reveals that the 16 criteria have differential comparative advantages, which requires critical judgement during contractors’ pre-evaluation process. Although the overall priorities rank multinational construction corporations (MCC) higher than local construction companies (LCC), it is not absolute that MCC will deliver a better value for money on all tangible and intangible elements of sustainable infrastructure attributes. LCC outperform on some of the key criteria such as local employment creation and local material sourcing, which are essential pre-evaluation criteria. This research proposes a novel framework to harmonise sustainability indicators in contractor selection and offers a new theoretical insight into the approach to contractors’ selection criteria during pre-evaluation process, which contributes to the enhancement of PPP delivery in Nigeria. Overall, the proposed SID model has demonstrated the need for a shift in the modus operandi of the government’s ministries, department and agencies (MDAs) in Nigeria from unidirectional to systemic selection techniques. It clearly demonstrates the appropriateness of the ANP to predict the contractor that will deliver more sustainable infrastructure.
Shape grammar based adaptive building envelopes: Towards a novel climate responsive facade systems for sustainable architectural design in Vietnam.Ceranic, Boris; Tracada, Eleni; Nguyen, Ngoc Son Tung (University of Derby, 2020-01-14)The concept of a dynamic building enclosure is a relatively novel and unexplored area in sustainable architectural design and engineering and as such, could be considered a new paradigm. These façade systems, kinetic and adaptive in their nature, can provide opportunities for significant reductions in building energy use and CO2 emissions, whilst at the same time having a positive impact on the quality of the indoor environment. Current research in this area reports on a growing increase in the application of new generative design approaches and computational techniques to assist the design of adaptable kinetic systems and to help quantify their relationships between the building envelope and the environment. In this research, a novel application of shape grammar for the design of kinetic façade shading systems has been developed, based upon a generative design approach that controls the creation of complex shape composites, starting from a set of initial shapes and pre-defined rules of their composition. Shape grammars provide an interesting generative design archetype in which a set of shape rules can be recursively applied to create a language of designs, with the rules themselves becoming descriptors of such generated designs. The research is inspired by traditional patterns and ornaments in Vietnam, seen as an important symbol of its cultural heritage, especially in the era of globalisation where many developing countries, including Vietnam, are experiencing substantial modernist transformations in their cities. Those are often perceived as a cause of the loss of both visual and historical connections with indigenous architectural origins and traditions. This research hence investigates how these aspects of spatial culture could be interpreted and used in designing of novel façade shading systems that draw their inspiration from Vietnamese vernacular styles and cultural identity. At the same time, they also have to satisfy modern building performance demands, such as a reduction in energy consumption and enhanced indoor comfort. This led to the exploration of a creative form-finding for different building façade shading configurations, the performance of which was tested via simulation and evaluation of indoor daylight levels and corresponding heating and cooling loads. The developed façade structures are intended to adapt real-time, via responding to both results of an undertaken simulation and data-regulation protocols responsible for sensing and processing building performance data. To this extent, a strategy for BIM integrated sustainable design analysis (SDA) has also been deliberated, as a framework for exploring the integration of building management systems (BMS) into smart building environments (SBEs). Finally, the research reports on the findings of a prototype system development and its testing, allowing continuous evaluation of multiple solutions and presenting an opportunity for further improvement via multi-objective optimisation, which would be very difficult to do, if not impossible, with conventional design methods.