Feasibility Study of 4D CAD in Commercial Construction

The Architecture, Engineering and Construction industry is under constant pressure to increase the quality and speed of its production delivery processes. This is due to the mutual competition amongst the industry's constituents and the growing demands of clients who expect faster delivery and higher quality. This has encouraged the AEC community to explore alternative ways in conducting project execution, which can provide a competitive edge over their contemporaries and satisfy the requirements of their customers. Research members at the Center for Integrated Facility Engineering (CIFE) at Stanford University have responded to these challenges by investigating ways of using Information Technology (IT) innovations that can improve and automate production processes. One such development is 4D CAD, which can be used as an alternative to CPM networks or bar chart schedules for project planning and control. The primary objective of this thesis is to determine the benefits and limitations of 4D CAD by conducting a feasibility study of the project planning tool. 4D CAD links three dimensional graphic images to the fourth dimension of time (30 CAD + time). The resulting 4 0 simulation or 4 0 model, visually demonstrates building components being built according to the sequence of the original building construction. As 4D models communicate the schedule as objects within the graphical model, the temporal and physical aspects of the project are inextricably linked. This increases the possibility of detecting unanticipated problems beforehand by viewing the 4D model. The 4D model also allows multiple project participants to communicate and interact through a single medium while developing the 4D model, and can be used to conduct additional planning related analyses. These benefits are demonstrated in a case study implemented by adapting 4D CAD for a commercial construction project. A 4D model is developed for an office building by linking 3D CAD components to an as-planned CPM schedule using commercially available 4D tools. By documenting the procedural difficulties involved in generating and analyzing the 4D model, the shortcomings of current 4D models and 4D tools are also established. Future improvements of current 4D models and 4D tools include expedition of the development process, manipulation of the 4D model, and the enhancement of its functional features to detect problems and convey the information to users. Current research which have addressed these issues are introduced and additional solutions based on the experience gained from the case study are also suggested. To proliferate the use of 4D CAD as a project planning tool, both the research and business sector of the AEC community industry must make a concerted effort. Advocates of the 4D CAD model must inform the industry of the benefits that can be gained from its usage as a project planning tool. The AEC industry, in turn, must be willing to explore this new technology and encourage its constituents in using it.