CONSTRUCTION

Construction



Construction

Introduction

The current state of the business world demands expedient delivery of construction projects. A widely used industry approach is the overlapping of the traditionally sequential design and construction phases. A more acute variation of this is the overlapping of design and construction activities or packages. The degree to which design and construction activities may be overlapped is defined by the nature of the information exchange between those activities. Concurrent engineering literature describes this information exchange between an upstream task and a downstream task in terms of the natural rate of evolution in each task and the sensitivity of the downstream task to changes in upstream information. This study expands on previous efforts that developed a framework and identified overlapping strategies that streamline the design phase. In the previous work, the authors described the concepts of evolution and sensitivity as they relate to the overlapping of design activities in the architecture, engineering, and construction industry.

Many times design does change, even in traditional design- bid-build environments (Elvin 2003). For this reason, it is even more critical that practitioners consider the potential risks when overlapping design and construction activities. Otherwise, the consequences may offset the gains produced from overlapping and even increase the time to finish construction compared to a traditional delivery approach. One approach to reducing the risk associated with overlapping design and construction activities is to consider the sensitivity of construction activities to changes in upstream design information. The concept of sensitivity was first developed in work by (Krishnan et al. 1997) for the overlapping of design activities in product development for the manufacturing industry. Sensitivity is a measure of the amount of rework required in a downstream activity due to changes in an upstream activity. In a highly sensitive activity, upstream changes cause a large amount of rework. Conversely, in an activity with low sensitivity, large amounts of information change produce small rework. In design activities, a small amount of rework could mean a slight revision to the design calculations, whereas a large amount of rework could mean a total change in the product concept.

As construction is a physical activity, if design changes occur they may cause physical rework (e.g., adding more concrete to a foundation or replacing one window with another). This type of rework often results in increases in project duration and cost. Therefore, an analogous definition of sensitivity of construction activities to design changes may be as follows: the amount of physical rework caused by upstream design changes (Fig.). For the purpose of this study the focus is on the rework resulting from changes in design activities that correspond to the component being built by the construction activity (e.g., the effect of changes in foundation design on the construction of the foundation that has already started). Although the concept of sensitivity of construction activities is used in other research work, the basic characterization of the sensitivity of construction activities is not addressed in detail. The main focus of the present research is to ...