Identification of cost factors for integrated alternative cost and time analysis in pre-construction stage

As construction industry shows a rapid growth, construction companies expand their services beyond the borders of their nations. Competitiveness increases due to open markets and hence it becomes harder for construction companies to get new jobs. Minor cost differences cause a contractor to lose a bid worth millions of dollars. Hence, estimating practices and alternative project estimation formations become more important. Any action to form alternatives on project cost and time in tender and pre-construction stages, in which the project estimation is formed and finalized, can help a contractor to survive in sector. Currently, conventional alternative analysis approaches are conducted by experts in companies by considering various factors affecting cost. Decisions on which factors to be considered, however, are determined based on experts' experience and know-how. The main purpose of this thesis is to identify the cost factors for integrated alternative cost and time analysis in pre-construction stage. The three main objectives of this study are: (1) to identify cost factors that are needed when performing alternative cost and time analysis; (2) to describe conventional alternative cost and time analysis approaches; (3) to identify which factors from determined requirements are being used in conventional approaches. The thesis is conducted through a detailed literature review and two sets of interviews. Pre-interviews were conducted with three experts while second set of interviews were conducted with eight experts. The experts were selected from three different project types; residential buildings, conventional building, and infrastructure. Pre-interviewees experience level varies as 10, 16 and 20 years. Current positions of these experts are project manager, technical office manager and managing partner respectively. Experience level of second set of interviewees varies between 10 to 22 years and their current positions are chief project controller or manager. To achieve the first objective of thesis, cost factors that are used in alternative formation are revealed with a detailed literature review. These factors are expanded with pre-interviews. Following this, second set of interviews are conducted to finalize and validate the required cost factors. In total, 34 required cost factors are found that are used in forming alternative cost and time analysis. The findings are grouped under five principal categories; equipment, crew, site access and logistics, construction process, and construction method. The factors under each principal category are discussed in detail by pointing out in which manner they form alternative project cost. Conventional alternative cost and time analysis approaches are also revealed by interviews in order to accomplish the second objective of the thesis. Experts were asked about their conventional alternative formation practices in the interviews. Finally, for the third objective of the thesis, interviewees were given the determined factors and asked to select which factors they use among the listed ones. Cost factors used in conventional approaches for three different construction types; commercial building, residential building, and infrastructure construction are compared with the required cost factors. The results show that although some factors used in conventional alternative analysis approaches are common for all three types, there are some differences among different project types due to the characteristics of the project. Finally, to eliminate the biased and limited approach of individual expert and provide a structured approach, the need for an integrated system for alternative cost and time analysis is highlighted based on the requirements that are identified.