Iteration during the design phase of construction projects has two opposite aspects. On the one hand iteration is required to solve complex problems and in aesthetic work. Thus, iteration will increase product quality. On the other hand, iteration in the design phase is a major source of time and cost overruns in construction projects. The planning phase is complex, iterative and multidisciplinary. Because of its complex structure rework can lead to cascading effects where the downstream activities that are already underway or completed are affected. To ensure the design quality changes need to be communicated between all the actors involved, which requires additional communication efforts. In order to keep the schedule, additional resources need to be activated, in unfotunate cases the the entire time schedule must be changed. Since the process is iterative, it is often difficult to identify the causes and effects of changes, which can lead to disputes and complicate contracting. Design changes are common in construction projects. They occur for example if the specifications (technical, aesthetic or monetary) can not be met, if the specs are changed or reinterpreted, if they cannot be realized because of production or transportation, or if the wrong conditions for construction are assumed and so on.
The Swedish wood industry over the past two decades has made intensive efforts to develop standardized construction systems where wall or volumetric elements are produced in the factory. On the one hand, the offsite systems result in stable and controlled production conditions. On the other hand, however, the demands on accuracy planning, collaboration and resource and time management are higher compared to traditional construction projects.
A better understanding of the frequency with which iterations occur and how they affect the work sequence in detail can thus helping increase efficiency and lead to the development of more robust processes.
By using models based on design structure Marix, Monte Carlo simulations and sensitivity analyzes, I explore how the effect of iterations on the work sequence can be measured and compared between projects. Based on the process models I have produced, I develop tools that will support project managers to systematically improve the design process of offsite construction projects with respect to iteration.