Abstract
Urban rebuilding efforts in the aftermath of destructive events such as natural hazards or war invariably require allocation of scarce resources to multiple projects that run concurrently. In such scenarios, the construction firms available in a geographic locality may have insufficient capability to cope with the scale of all the rebuilding projects. In such cases, construction firms from outside of the immediate region, but with the required capabilities, may be needed to supplement local capacity. Use of such external capacity incurs additional financial and environmental penalties (e.g., carbon footprint) due to the need to transport heavy equipment, supplies and labor over greater distances. As such, it is necessary to maximize the use of locally available firms, and hence to minimize the need for external ones. The problem is conceptually similar to the optimization of Resource Conservation Networks (RCNs), and lends itself to being solved via Process Integration (PI) approaches. In this work, a source-sink model is developed to optimize the assignment of construction firms to multiple concurrent projects taking place during a concerted urban rebuilding campaign. The model is formulated as a Mixed Integer Linear Program (MILP) whose objective function is to minimize total carbon footprint during urban rebuilding. This carbon footprint is proportional to the project cost and the distance of the construction firm’s headquarters to the city where urban rebuilding is needed. A semi-hypothetical case study on urban rebuilding in the southern Philippines is used to illustrate the application of the model.
