Specialist contractors – generally known as subcontractors – perform the majority of the work on commercial construction projects. They face significant challenges in allocating their resources across multiple, concurrent projects (O’Brien and Fischer 2000). Despite their central nature to project performance, relatively little research has been performed to formally model their operations. Without such modeling, there exists little basis from which to measure or improve performance. This dissertation attempts to address the limited literature by providing a formal, information model for subcontractor resource management. There are three main contributions: First, addition to the general literature on subcontractor management as a precursor to formal modeling. Second, an information model for subcontractor resource management. This model is expressed in UML (the Unified Modeling Language) and implemented in code. Third, as part of the information model, an extension to the Process Connectors architecture (Siddiqui et al 2008) to add resource constraints to distributed schedule coordination. Model development and validation is performed through case studies with subcontractors and general contractors. Collectively, the contributions of this research provide a practical basis for describing and representing subcontractor resources that can improve practice as well as provide a foundation for future prescriptive research.
1.1 Motivation: Subcontractor Multi-Project Resource Allocation
On construction projects, it is common that the majority of work is performed by subcontractors. Thus, understanding subcontractor’s issues, concerns and the ways how they coordinate with general contractors are vital. Existing literature, case studies and interviews, show that 1) subcontractors work in a multi- project environment, 2) current tools and techniques primarily focus on single projects and do not support distributed process coordination, and 3) resource management is the key issue for subcontractor’s business. For example, frequent delays result in schedule changes, so subcontractors face challenges to manage their resources. However, existing commercial applications cannot fully represent subcontractors’ (subs’) resource allocation needs well. As noted by Ibbs and Nguyen (2007), the need for representing and capturing the practice of resource allocation is “apparent and imperative.” Unfortunately, existing literature is missing a way which can detailed describe the processes of resource allocation. There is a pressing need to provide such a representation as a basis to improve subcontractor resource management performance.
1.2 Case Study: Ellis Air Subcontractor
A case study conducted as part of this research is briefly previewed . Ellis Air is an air/mechanical subcontractor located in Melbourne, Australia. Ellis Air currently has twenty three employees and works on seven to eight projects concurrently. The number of employees varies from...