Browsing by Author "Stevens, Alan J"
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- ItemOpen AccessDesigned for durability in reinforced concrete structures, and associated economics(1997) Scott, Allan Nye; Alexander, Mark Gavin; Stevens, Alan JThis dissertation outlines a model developed to allow for the comparison of various design options on a life-cycle cost basis for reinforced concrete structures. The model consists of two interlinked components: the first part of the model is technical, and can be used to estimate the service life of a structure within a specified environment based on a set of prediction models; the second part of the model is used to determine the economic implications of the various design options over a specified evaluation period. The use of a particular predictive model is subject to the environment in which it was calibrated. In many cases the models which are presented were developed overseas and as such their values may not be directly applicable to South African environments. The approaches and development of the models are however useful and if calibrated to particular South African environments could be of considerable benefit. A survey of consulting engineers was also conducted to determine common perceptions of various durability related issues. The results of the survey are presented in this project. The size of the sample was relatively small and as such it would be inappropriate to apply the results categorically to all engineers or organisations. The survey is of value however in that it identifies some areas of potential opposition to the concept of designing for durability and highlights other areas where its acceptance and implementation may be more favourable.
- ItemOpen AccessDeterioration of reinforced concrete in a marine environment : repair costs and maintenance strategies(1994) Strohmeier, Jörg Harald; Alexander, Mark Gavin; Stevens, Alan J; Mackechnie, James RThis dissertation comprises an investigation into the rate at which reinforced concrete structures deteriorate in the Cape Peninsula due to reinforcement corrosion, the reasons for this deterioration, and the accompanying repair costs. The costing of repair work is calculated per m2 of reinforced concrete and is based on quoted labour rates and material rates of repair materials supplied by four major suppliers in the Western Cape. Formulas are included which enable a person using the data listed in tables and figures to calculate what repair costs will be in future, and also enable the calculation of monthly/annual deposit amounts in order to save sufficient money for future maintenance at a specified date. Life cycle costing and decision models for the maintenance of concrete structures are discussed and guidelines for the establishment of optimal maintenance cycles are included. Based on the results of the life cycle costing exercise the importance of planned preventative maintenance is highlighted. Finally, locally and internationally available maintenance management computer systems are reviewed.
- ItemOpen AccessThe Economics of Building Life Cycle Costing(1978) Stevens, Alan JIf one is to arrive at a true reflection of the investment potential and total cost of a particular real property investment the appraisal method used must be capable of allowing for the following factors which, although by no means complete, incorporates those aspects which are required to give a valid and meaningful assessment of the investment . 1. Comparisons to be made with alternative investment opportunities 2. Limited life of certain components in a building which may have to be repaired or replaced 3. Comparisons to be made with alternative materials and/or forms of construction 4. The total costs and income generated throughout the effective life of the building including residual value at the expiry of the investment 5. The effect of the time value of money and the impact of inflation 6. Income tax implications 7. Adaptation to the individual characteristics of each specific project Life cycle costing which is essentially similar in concept to costs-in-use or terotechnology, is a sophisticated method of appraisal capable of satisfying the abovementioned needs. It could be defined essentially as: A financial appraisal technique which allows valid comparative evaluation of available alternative possibilities based on time-phased costs over a specific investment period in order to arrive at the optimum economic solution. The purpose of this thesis is to examine the economics of buildings with special reference to life cycle costing in order to illustrate how valid comparisons of alternative construction methods or material selection can be achieved with a view to optimizing total costs.
- ItemOpen AccessRisk management in the cost planning and control of building projects : the case of the quantity surveying profession in Kenya(2005) Wanyona, Githae; Bowen, Paul; Rwelamila, PDM; Akintonye, A; Stevens, Alan J; Root, DavidThis thesis examines financial risk management in the cost planning and cost control of building projects in Kenya. The quantity surveying professional in Kenya is faced with poor access to the recorded cost data needed for preparing final building cost estimates and for budget prediction. This shortcoming is exacerbated by the passive role played by the professional building cost consultant during design development. Passive professional building cost consultants are unlikely to implement risk management strategies as part of the cost planning and cost control process. The proactive identification of risks and their outcomes is essential for budget prediction and for estimating future risk impacts. The need exists for a generalised procedure that can use the limited available project information, adapting it to specific projects through identified risk indicators such as risk groups, clusters and broad subsets. The primary objectives of the research project were to identify the characteristics of risk in current practice of cost planning and cost control of building projects, and to investigate the efficacy of the techniques employed to assess risk and risk impact in cost prediction.