Browsing by Author "Drennan, Michael Bryan"
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- ItemComparative construction costs of typical low-rise office buildings in South Africa(Stellenbosch : Stellenbosch University, 2017-03) Drennan, Michael Bryan; De Clercq, Hennie; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.ENGLISH ABSTRACT: Low-rise multi-storey office buildings are required globally on a regular basis, and have thus become an increasingly important field within the engineering industry. A critical decision that has to be made during the initial stages of the planning and design of such a building is the selection of the structural framing material. This decision typically involves choosing between steel and reinforced concrete and is important as it will influence both the construction time and cost. In South Africa, concrete is currently the default option for the framing material of multi-storey office buildings. This is in contrast to some other parts of the world where steel frames hold a dominant market share. Very little information on the costs and construction time could be traced which provided a comparison of steel and concrete framed office structures in South Africa. This study aims to fill this knowledge gap by providing a cost comparison between steel and concrete structural alternatives for the structure of a typical low-rise office building. A building configuration was developed that can be seen as being representative of a typical low-rise office building in South Africa. Its structure was then designed employing various steel and concrete structural alternatives. Several meetings were held with industry professionals during the study to obtain insight into current South African construction practices, including steel fabricator’s preferences, construction times and costs, and designer’s preferences to name a few. The construction programmes for each of the structural alternatives were developed in detail and compared. It was shown that the steel structures were able to offer a shorter construction time of approximately one month when compared to the concrete structures. This equates to a reduction of 12.5 % in the total construction time. A detailed cost comparison was developed using 2016 South African construction costs in the Western Cape. In addition, the influence of time-related costs, such as lower preliminary and general (P&G) costs, reduced interest charges and the ability to earn income at an earlier stage, were all incorporated into the cost comparison. Thereafter, a sensitivity analysis was performed to better understand how changing various parameters would influence the cost model. The study revealed that for a typical low-rise office building constructed in South Africa, a steel framed structure supporting hollowcore units acting compositely with the steel beams, provided the most cost-effective solution. The difference between the cheapest steel and concrete structural alternatives was found to be 0.6 % of the total construction cost, which equated to a cost difference of approximately R 150 000.00. Furthermore, the study presented a methodology for developing cost comparisons between different structural alternatives, and highlighted the importance of considering time-related costs when doing a cost comparison.