An investigation into the time and cost factors for a decision between in-situ and hybrid concrete construction

Piek, Philippus Jacobus (2014-12)

Thesis (MEng)--Stellenbosch University, 2014.

Thesis

ENGLISH ABSTRACT: The construction industry is a competitive market and contractors need to keep up-to-date with new construction methods and technologies. Project teams in South Africa are required to make decisions during the early stages of construction projects. These decisions often need to be made in a short time period, and include the decision between various construction methods, such as the decision between in-situ concrete construction and hybrid concrete construction. Hybrid concrete construction is a combination of pre-fabricated concrete and cast in-situ concrete to obtain the supreme benefits of their different construction qualities. This method of construction is ultimately used to achieve faster, and occasionally, more cost effective construction. Hybrid concrete construction, today, is a well-known term in the construction industry and is widely used in the UK and other developed countries. However, the use thereof is limited in South Africa, and in-situ concrete construction remains the conventional method of construction. Possible reasons for the limited use of hybrid concrete construction are investigated in this study. With the intent of improving the construction industry of South Africa, guidelines are provided to assist project teams in a decision between in-situ concrete construction and hybrid concrete construction. The decision between construction methods is based on many factors, such as project time, cost, quality, safety, environmental performance, socio-economic aspects (labour) and client satisfaction. Project time and cost are, however, the most important of these factors. It is stated that the structure of a building represents typically only 10 % of the construction cost, however, the choice of construction method and material can have significant effects on the cost of other elements throughout the life cycle of construction projects. It is therefore important to measure the whole life cycle cost when deciding between construction methods, such as in-situ concrete construction and hybrid concrete construction. The aim of this study is to identify and investigate the factors that influence project time and cost, throughout the life cycle of construction projects, and to provide a framework that can assist project teams in their decision between in-situ concrete construction and hybrid concrete construction in South Africa. The decision between these two construction methods is influenced by a vast number of variables that may be difficult to quantify. The framework therefore consists of qualitative information that can assist project teams in their decision. The framework provided in this study includes the factors that have an influence on the time and cost for a decision between in-situ concrete construction and hybrid concrete construction. These factors are identified for the three primary phases in the life cycle of construction projects. These phases are the design phase, the construction phase and the maintenance phase.

AFRIKAANSE OPSOMMING: Die konstruksiebedryf is 'n kompiterende mark en kontrakteurs moet op datum bly met nuwe konstruksie metodes en tegnologieë. In Suid-Afrika word daar van projek spanne vereis om vinnige besluite gedurende vroeë stadiums van 'n projek te neem. Hierdie besluite moet dikwels in 'n kort tydperk geneem word, en sluit die besluit tussen verskillende konstruksie metodes in, byvoorbeeld die besluit tussen in-situ en hibriede beton konstruksie. Hibriede beton konstruksie (HBK) is 'n kombinasie van in-situ en voorafvervaardigde beton elemente. HBK word in die algemeen gebruik om te baat uit 'n vinniger konstruksie tydperk, en kan soms ook ‘n meer koste-effektiewe metode van konstruksie wees. HBK word gesien as 'n bekende term in die konstruksiebedryf en word veral toegepas in ontwikkelde lande soos die VSA, Japan en Engeland. Die toepassing daarvan in Suid-Afrika is egter beperk. In Suid-Afrika word in-situ beton konstruksie nog steeds die meeste gebruik en staan dus bekend as die mees algemene metode van konstruksie. Hierdie studie ondersoek moontlike redes vir die beperkte gebruik van HBK in Suid-Afrika. Met die oog op 'n verbeterde konstruksiebedryf in Suid-Afrika, word rigylyne voorsien, wat projek spanne kan gebruik vir 'n besluit tussen in-situ en hibriede beton konstruksie. Daar is verskeie faktore wat 'n rol speel in die besluit tussen twee konstruksie metodes. Hierdie faktore sluit in, die tyd, koste, kwaliteit, veilighed, omgewings impak, sosio-ekonomiese aspekte (soos arbeid) en kliënt tevredenheid, van 'n projek. Tyd en koste is egter die belangrikste van hierdie faktore. Die metode waarvolgens 'n struktuur gebou word kan 'n beduidende uitwerking op die koste van ander elemente in die lewensiklus van 'n konstruksie projek hê. Dit is gevolglik belangrik om die hele lewensiklus koste in ag te neem wanneer daar besluit moet word tussen verskeie konstruksie metodes, soos in-situ en hibriede beton konstruksie. Die doel van hierdie studie is gevolglik om die faktore wat 'n invloed het op die tyd en lewensiklus koste van konstruksie projekte te identifiesieer. Hierdie faktore word dan gebruik om 'n raamwerk voor te stel. Projek spanne kan hierdie raamwerk gebruik as 'n riglyn om te besluit tussen in-situ en hibriede beton konstruksie. Die besluit tussen hierdie twee konstruksie metodes is afhanklik van 'n groot aantal veranderlikes, wat moeilik is om te kwantifiseer. Die raamwerk bestaan dus uit kwalitatiewe inligting wat projek spanne kan gebruik om 'n ingeligte besluit te neem oor in-situ en hibriede beton konstruksie. Die raamwerk wat in hierdie studie voorgestel word sluit dus die faktore in wat 'n invloed het op die tyd en koste vir 'n besluit tussen in-situ en hibriede beton konstruksie. Hierdie faktore is geïdentifiseer vir die drie primêre fases in die lewensiklus van 'n konstruksie projek. Hierdie fases is die ontwerp fase, die konstruksie fase en die onderhoud fase.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/95857
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