Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: A construction method that proves to be the best today will not necessarily be the best method for application in 20 years. Therefore, with changing circumstances, engineers have to consider all the options before selecting a specific method. Options that are weighed in this study are in-situ concrete construction and hybrid concrete construction. Hybrid concrete construction is the combination of in-situ and precast concrete in structures, with the purpose to exploit the advantages of each to its full potential. This construction method gained popularity in the United States and in Europe due to its distinctive benefits. However, the increase of its application in some countries (including South Africa) has been slow and possible reasons for this are investigated in this study. With the intention of improving the South African construction industry, a model is developed for decision making between hybrid concrete construction and insitu concrete construction. The main purpose of a larger research project is to assist project teams in the decision making between precast concrete and in-situ concrete in building construction projects. This decision making is not based on decision making models with mathematical output, since the decision of a construction method is influenced by many variables that may not all be quantifiable. Consequently, instead of prescribing a decision making method, the relevant information is to be provided for the decision maker. The aim of this study is to identify the relevant parameters and to set a framework for further in depth investigation by subsequent theses. A decision making process in any field normally involves having a list of advantages and disadvantages of the different options. Therefore this study includes the following managerial discussion topics: factors that influence hybrid concrete construction, as well as benefits, barriers and other aspects to consider, structural systems and elements, decision making methods and important factors that will be the basis of the decision making process. Traditionally the most important factors for decision making between construction methods were construction cost and duration, but more recently sustainability is becoming increasingly important. It is the civil duty of all parties involved in a project to foresee that most of the criteria of sustainability are met. Sustainability covers all the aspects of economic, social and environmental impacts. Furthermore quality is identified as an important aspect in the decision making process for a construction method. The comparison of precast and in-situ concrete construction is therefore discussed, considering all the abovementioned criteria and investigating possible quantification methods. This information, together with information from future studies, would then allow the project team to consider each aspect involved in the decision making process. / AFRIKAANSE OPSOMMING: Die beste konstruksiemetode vandag sal nie noodwendig die beste metode oor 20 jaar wees nie. Met veranderende omstandighede, moet ingenieurs altyd al die moontlike opsies oorweeg voordat ‘n spesifieke konstruksiemetode gekies word. Opsies wat in hierdie studie bestudeer word, is in-situ betonkonstruksie en hibriede betonkonstruksie. Hibriede betonkonstruksie is die kombinasie van in-situ en voorafvervaardigde beton elmente in strukture, ten einde die voordele van elke metode ten volle te benut. As gevolg van sy voordele, het hierdie konstruksiemetode al hoe meer gewild geraak in Amerika en Europa. Nietemin is die toename in die gebruik van hierdie metode in sommige lande (insluitend Suid-Afrika) traag en moontlike redes hiervoor word in hierdie studie ondersoek. Met die voorneme om die Suid- Afrikaanse konstruksie-industrie te bevorder, is ‘n model vir besluitneming tussen hibriede betonkonstruksie en in-situ betonkonstruksie ontwikkel. Die hoofdoel van ‘n groter navorsingsprojek is om projekspanne te help met die besluitneming tussen voorafvervaardigde en in-situ beton in konstruksieprojekte vir geboue. Hierdie besluitneming is nie gebaseer op besluitnemingsmodelle wat wiskundige resultate lewer nie, want die keuse van ‘n konstruksiemetode word deur te veel veranderlikes, wat nie altyd kwantifiseerbaar is nie, beïnvloed. Gevolglik word relevante inligting aan die besluitnemer verskaf, eerder as om ‘n gekwantifiseerde besluitnemingsmetode voor te skryf. Die doel van hierdie studie is om relevante aspekte te identifiseer en om ‘n raamwerk te skep vir verdere, in diepte studies van volgende tesisse. ‘n Besluitnemingsproses in enige veld word gewoonlik gebaseer op ‘n lys van voordele en nadele van die verskillende opsies. Daarom sluit hierdie studie die volgende bestuursaspekte in: faktore wat hibriede betonkonstruksie beïnvloed, asook voordele, beperkings en ander aspekte om te oorweeg, strukturele sisteme en –elemente, besluitnemingsmetodes en belangrike faktore wat die basis van die besluitnemingsproses sal wees. Tradisioneel was die belangrikste faktore vir besluitneming tussen konstruksiemetodes die koste en tydsduur daaraan verbonde, maar deesdae word volhoubaarheid al hoe meer belangrik geag. Dit is die plig van alle persone betrokke by ‘n projek om te sorg dat die projek aan so veel as moontlik van die kriteria van volhoubaarheid voldoen. Volhoubaarheid sluit al die aspekte van ekonomiese-, sosiale- en omgewingsimpakte in. Verder is kwaliteit ook geϊdentifiseer as ‘n belangrike aspek in die besluitnemingsproses van ‘n konstruksiemetode. Die vergelyking van voorafvervaardigde- en in-situ betonkonstruksie word dus bespreek met die oog op al die bogenoemde kriteria en, sover moonlik, word die kwantifisering van hierdie aspekte ondersoek. Met hierdie inligting en die inligting van toekomstige studies, kan die projekspan dan elke aspek in die besluitnemingsproses oorweeg.

Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Hybrid concrete construction (HCC) is a construction technique that makes use of both in-situ and pre-fabricated concrete products by making optimum use of the advantages of both these methods in the same project. Although the advantages of this building method is well recognised throughout the world and a feasibility study illustrated that HCC is a suitable building method in South Africa, it remains under-utilised in the country. HCC encourages early involvement from the project team and provides clients with the best value projects and a "win-win" situation for the project team during the project development. The objective of this study is to identify barriers that prohibit an increased utilisation of HCC for the South African construction industry. Additionally, it provides possible solutions to overcome these barriers. These proposed solutions are similar to the programmes and methods that are implemented in other countries to improve their HCC utilisation. Furthermore, drivers are identified in this study to implement these solutions in the industry and a proposed "change model" is developed for private companies to assist with the change process. This study is unique because current South African conditions are used to establish the barriers and solutions. Furthermore, it takes into account that not all countries have such progressive construction industries as the European markets and therefore it considers solutions and drivers that are suitable for less advanced industries such as South Africa. The model that is proposed is applicable to any industry regardless of its nature or country. Although the United Kingdom is not the widest user of pre-fabricated concrete products, their HCC research is extensive, making it a suitable comparative country for the South African construction industry. During the investigation, the procurement methods in South Africa were found to be traditional and do not allow for early involvement or partnering in the project team. To obtain early involvement, it is critical to initiate methods such as design-and-build, contract management or public-private-partnerships during the procurement phase. Decision and design assistance from the whole project team and software tools are essential when HCC is considered. Because the South African construction industry does not provide such support it is advised here to incorporate contractors from an early stage and to develop software tools that can assist during the decision making and design process of HCC structures. The industry does not provide the project team with sufficient training programmes that increase knowledge of HCC. Training programmes that are cognitive stimulating must be developed for the industry. Furthermore, a database is required to illustrate the utilisation of different pre-fabricated products and in different projects within South Africa. Labour-intensive construction regulations and green building techniques (not compulsory) are promoted in South Africa. Labour-intensive programmes should consider the negative impact it has on the labourers and consider HCC as a building technique because the pre-fabricated elements are manufactured in a controlled and safe environment. It is advised that the toolkits that are used for green building accreditation, must be revised to accommodate the additional benefits such as less waste generation, that HCC offers to a project. Regardless of the country in which HCC is utilised, the environment must be acceptable for the innovation. By analysing the criteria that influences the use of HCC in a country and adding weighting functions to these criteria, the acceptability towards the innovation can be obtained. Furthermore, public clients and companies are recognised here as drivers of change. While public clients can commit to HCC for the cost, labour-intensive factories, green building methods, improved health and safety, training for labourers, private companies can utilise HCC to provide best value to a project. A model is proposed here for innovative companies that will allow them to change not only the company, but the industry towards a HCC "mindset". / AFRIKAANSE OPSOMMING: Hibriede beton konstruksie (HBK) is ’n tegniek waarby beide voorafvervaardigde betonelemente en in-situ beton in dieselfde projek gebruik word ten einde voordeel uit beide metodes te trek. Alhoewel die voordele van die konstruksietegniek wel bekend is in talle lande van die wêreld en ’n uitvoerbaarheidsanalise getoon het dat HBK ’n voordelige konstruksiemetode vir Suid-Afrika is, is dit tans onderbenut in die plaaslike sektor. HBK bied vir kliënte projekte van goeie waarde en omdat dit vroeë betrokkenheid verg vanaf die projekspan, resulteer dit ’n "wen-wen" situasie tydens die projekontwikkeling. Die doel van hierdie studie is om die hindernisse te ondersoek wat veroorsaak dat HBK nie meer gereeld in Suid-Afrika gebruik word nie. Ten einde die effekte hiervan te verminder, word moontlike oplossings vir hierdie hindernisse voorgestel. Die oplossings is gebaseer op tegnieke en metodes wat geïmplimenteer word in ander lande waar HBK gebruik word. Rolspelers wat hierdie verandering na HBK kan dryf word geïdentifiseer en ’n model om verandering binne ’n maatskappy te lei word voorgestel om die rolspelers te ondersteun tydens die proses. Hierdie studie is uniek omdat dit inligting gebruik van die huidige situasie van die Suid-Afrikaanse konstruksie-industrie om die hindernisse en oplossings te identifiseer. Omdat nie alle konstruksie-industrieë so vooruitstrewend is soos in Europese lande nie, is die oplossings en rolspelers relevant vir enige land wat ’n industrie het wat soortgelyk is aan Suid-Afrika. Die model wat voorgestel word is ook relevant tot enige industrie afgesien van die land waar nuwe tegnieke geïmplimenteer word. Alhoewel dit bevind is dat die Verenigde Koningkryk nie die grootste gebruikers van HBK is nie, is hulle navorsing in die veld omvattend. Daarom word die Verenigde Koningkryk beskou as ’n voorbeeld om Suid-Afrika se konstruksie-industrie mee te vergelyk, asook om inligting van HBK te verkry. Tydens die studie is bevind dat die projekaanstellingsmetodes van projekte in Suid-Afrika tradisioneel is, aangesien dit nie toelaat vir vroeë betrokkenheid of vennootskappe binne die projekspan nie. Om vroeë betrokkenheid te verkry, is dit noodsaaklik om van ontwerp-en-bou, kontrakbestuur of publiek-privaat-vernootskappe gebruik te maak. Tans is daar geen hulp wat aan ontwerpers verleen word ten opsigte van besluitnemingsmodelle en ontwerpsagteware wanneer HBK oorweeg word in Suid-Afrika nie. Die behoefte aan sulke bystand dui daarop dat sagtewarepakkette ontwerp moet word wat toepaslik is vir Suid-Afrika se konstruksie-industrie. Die industrie bied nie doelgerigte en genoegsame opleidingsprogramme aan om die industrie se kennis van HBK te verbreed nie. Addisionele opleiding wat kognitiewe stimulasie sal bied vir die hele projekspan word aanbeveel. ’n Databasis wat HBK projekte insluit, moet geskep word om die industrie bloot te stel aan die verskillende moonlikhede. Arbeid-intensiewe konstruksie-regulasies asook groen konstruksietegnieke (nie wetgedrewe nie) word sterk bevorder in Suid-Afrika. Dit word hier aanbeveel, dat voorafvervaardiging se addisionele voordele in ag geneem word wanneer hierdie regulasies en tegnieke relevant is. Hierdie voordele sluit onder meer in: die veiligheid wat aan werkers gebied word in arbeid-intensiewe fabrieke en die vermindering van afval in HBK projekte. Afgesien van die land waarin HBK gebruik word, moet die omgewing ontvanklik vir die tegniek wees. Deur verskillende kriteria te analiseer wat die gebruik van HBK beïnvloed binne ’n land en geweegde faktore daaraan te koppel, kan die ontvanklikheid van die innovasie bepaal word. Laastens word publieke kliënte en maatskappye as die drywers (of katalisators) wat verandering kan meebring, beskou. HKB bied onder andere die volgende voordele aan publieke kliënte: koste-effektiwiteit, arbeid-intensiewe werk, groen konstruksie, beter gesondheid, veiligheid en opleiding vir werkers. Maatskappye kan gebruik maak van HBK om waarde tot hul projekte toe te voeg. ’n Model word hier voorgestel om innoverende maatskappye in staat te stel om nie net hulself nie, maar ook die industrie as ’n geheel te help om ’n gesindheidsverandering jeens HBK te skep.

Thesis (MScEng (Civil Engineering))--Stellenbosch University, 2008. / Introduction South Africa is currently experiencing a significant increase in infrastructure investment. Forecasts by BMI-BRSCU have shown that the building and construction industry is expected to grow considerably to 2010, before languishing slightly to 2015. This growth will be driven in particular by investment in non-residential building (41% growth) and construction (73% growth) activities. Even beyond 2015 however, the demand will still be high on the construction industry to provide infrastructure for South Africa’s growing population. South Africa is also facing a serious shortage of engineers, technicians and other skilled workers in the construction industry. This places high demands on designers and contractors to provide services and to realise projects in ever-reducing time periods and at less cost. These conditions have made it increasingly difficult to maintain the required quality of construction in an industry where mistakes can lead to disastrous consequences. Recent advances in structural materials, structural systems and the way in which projects are handled, now enables a new look at the possibilities of combining pre-fabrication with on site work. This method, known as Hybrid Concrete Construction (HCC), has the potential to revolutionize the South African construction industry if applied correctly. Local research into this technique is however required and it is the aim of this thesis to draw attention to this subject. Key Findings Hybrid Concrete Construction (HCC) can be applied to any structural project, it will however not necessarily be successful. A structure needs to be adapted from the very start to suit a particular construction method. This ensures that all the advantages of the selected construction method may be achieved. Adapting a structure to a different construction method requires a mutual understanding and commitment from all project participants, including the architect, engineer, contractor and client. HCC also requires a certain degree of repetition in a project to be financially viable. A theoretical cost exercise was performed where only the material and erection costs were considered. In this exercise, HCC was found to be slightly less expensive than other construction methods for the Office Building of more than 10 storeys. HCC was also found to be significantly faster than other construction methods for the Office Building of more than 3 storeys. The time calculation was however based on the simplified time estimates from one source. Because of HCC’s shorter estimated construction period, the client can expect to earn revenue from a much earlier date. This decreases the relative cost of a HCC project. This advantage, however, needs to be quantified for chosen South African projects. On-site safety is still an important issue with HCC projects. Labourers are not accustomed to this construction method and it may be necessary to alter current skill development programs to include a crane safety course. The training of qualified riggers and crane operators should receive priority if HCC is to develop in South Africa. This preliminary investigation has shown that Hybrid Concrete Construction (HCC) can be feasible for the South African market. Further investigation is however required to determine the parameters for which HCC would be the preferred construction method. Recommendations Based on the findings and conclusions of this investigation, the following recommendations are made. The following actions should be undertaken by individual South African companies: · Develop relationships with external project partners · Train competent riggers and crane operators The South African concrete industry should invest in the following actions: · Invest in mass-producing precast concrete facilities · Develop a central database of South African projects with information on time, costs, project concepts and layouts to be used as a guideline for decision making · Develop local guidelines for the production and application of self compacting concrete · Compile guidelines for the design and construction of HCC and precast concrete construction in South Africa · Develop a local hidden corbel type connection to its full potential

Thesis (MEng)--Stellenbosch University, 2014. / 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.