The multidisciplinary nature of the Architecture-Engineering-Construction industry, the involvement of parties with different professional backgrounds and the use of incompatible software at different phases of project development result in fragile communication between design and construction. The software used at different phases of project development represents and manipulates product knowledge rather than process knowledge, so do the design drawings and specifications. The process knowledge that remains trapped in the design phase can however be used in interpreting the meaning about the form represented on design drawings. A better understanding of process knowledge can restructure and enhance construction related processes and strengthen the communication between design and construction. This research focuses on reconfiguring the flow of information between architectural design and construction by identifying that part of the process knowledge also referred to as "design intent," which is of essence to cost estimating. Design intent can improve various facets of cost estimating. This research discusses the potential use of design intent knowledge in material selection and substitution, shop drawing preparation and value engineering. The first objective of the research is to define the term design intent, find examples of it and classify it in a format that can be used in construction applications. Thus, design intent has been classified under four classification schemes in this research: (1) Attributive; (2) Relational; (3) Priority; and (4) Implicit/ Explicit. The first two classification schemes have further been structured into its detailed subclasses and the potential use of each type of design intent has been discussed in detail. The second objective of the research is to represent and reason with design intent to improve cost estimating applications. Thus, the thesis describes an object-oriented design intent representation model implemented in a proof-of-concept prototype called Skull Object Space (SOS). The benefits of using such a representation model is illustrated in a material application module implemented as a small scale computer prototype that makes material selection and substitution for the contractor. Both SOS and the Material Application Module provide useful framework for future enhancements in externalization and representation of design intent. / Master of Science

Thesis (MEng (Civil Engineering))--University of Stellenbosch, 2006. / Most construction projects do not complete exactly as scheduled or exactly as priced. During the implementation of a project there is almost certainly some deviation from the original estimate. The implementation of a majority of projects has actually been shown to cost more and take longer than originally estimated. However, the duration and cost performance of a project’s implementation is measured against the initial estimate produced. Thus if a project is considered to have completed late or over budget then essentially the duration or cost estimated was insufficient. Due to the fact that estimates are produced in a present day environment for inherently unique projects that occur in uncertain future environments, the estimates produced will need to incorporate uncertainty to increase their likelihood of achievability. This study aims to derive methods to incorporate future uncertainty into project estimates. This uncertainty is incorporated, analysed and manipulated through the use of Probabilistic models and First Order Second Moment Reliability methods. The derived methods provide project management professionals with tools that enable them to design estimates that incorporate future uncertainty and are reliable to a specified degree. Further methods are then derived to probabilistically assess the commercial feasibility of a project in an uncertain future environment. These derived methods then provide project managers and decision makers with more reliable procedures and information which in turn should assist them in making correct, project orientated decisions and ultimately increase profit reliability and client satisfaction.

The purpose of this study was to evolve how to reduce the manifestation of poor decisions that always produce defects and rework. The purpose of the study is predicated on the fact that good decision-making is a fundamental element of improved project delivery in the construction industry. Such decisions determine the accomplishment of performance parameters in each project. However, suboptimal performance, which is pervasive in the construction industry, is often linked to team decisions. To remedy decision-making pitfalls, the concept of Choosing by Advantages (CBA) is promoted by lean construction researchers. CBA is a decision-making system that assists project parties in deciding a course of action among competing alternatives. Case study research design was used for this project to discover the decision-making process adopted by project teams. The results from the study achieved through cross-case analysis shows that concrete defects and rework is often caused by the project team’s decision-making process, which is influenced by the members of the project team because of lack of experience, poor working conditions, and lack of education. The results also show that the decision-making mechanism of the project teams is influenced by the construction method, specification, cost, quality and time. The outcome of the project team’s decision-making process when choosing a concrete type often causes the concrete defects and rework, which can be eliminated through the application of CBA when choosing a concrete type. The application of CBA when choosing concrete type from two alternatives, ready mixed concrete and site batched concrete is driven by the project team. It was discovered from all three cases that ready-mixed concrete had a better score than site-batched concrete when using CBA to compare these two alternatives. The results show that ready-mixed concrete had less chances of causing concrete defects and rework when used or applied per the correct specifications or methods which are detailed in the engineering drawings of the structure. The study proposes that the project team should adopt CBA to improve their decision-making process on site especially when working with concrete.