what are resources?
Resources are the means of production needed to complete a project. Most project managers would consider the big three resources that will require your attention to be: material, labor, and equipment. A key idea when managing the overall capacity, availability, and allocation of resources on large construction projects is that the project manager’s perspective is from the level of completion of the project’s major features of work. Others on the team will be concerned with individual material or equipment deliveries, small tools, or the productivity of specific workers. Unless there is a specific, individual, constraint on labor, material, and equipment that could affect the completion of major features of work, a project manager views these issues at a high level.
labor
On large construction projects, the project manager can consider labor to be comprised of interchangeable crews whose workers have averaged levels of productivity. There are exceptions to every rule, of course, but from the point of view of the project manager, an average productivity rate may be assumed since the productivity of the crews can be assumed to be averaged out to industry norms over the entire length of the project.
There are two resource questions where the Critical Path Method can assist the project manager. These are the limited resource allocation question and the unlimited resource leveling problem. In each of these cases there are assumptions regarding crews and projects
| Management Technique | Crew | Delay | Objective |
|---|---|---|---|
| Limited Resource Allocation |
shortage | possible | finish job |
| Unlimited Resource Leveling |
abundant | no | limit turnover |
In the limited resource allocation case, there are two assumptions: (1) there are a fixed number of crews available to perform the work and (2) the project may be delayed as a result of the limitation of crews. The objective of the resource allocation problem is to determine when the project will be completed.
In the unlimited resource leveling case, there are two assumptions: (1) there are an unlimited number of crews available to perform the work and (2) the project may not be delayed. The objective of the resource leveling problem is to determine how to limit the fluctuation in crews required on the job.
Other concerns with respect to maximizing labor productivity include the maximization of the learning-curve and the crew-chase. Project managers typically would like crews to work on a similar type of work through the project. As workers perform similar work on the project, the productivity of the workers will increase since they will be familiar with the site, the materials, and the job conditions. Modeling the “crew-chase” allows the project manager to plan and communicate with each trade how their workers will move through the physical space of the project.
For some project management domains, such as the management of many small work-orders, assumptions regarding averaged crew productivity are not appropriate. The reader is referred to the academic literature regarding infrastructure resource management for more information on scheduling in small-works domains.
materials
The cost of material is governed by factors that are somewhat outside the control of the project manager. The designer specifies the required quality of materials to be installed. Procurement personnel receive bids to obtain the required materials at the least price. On-site storage is defined by the location of the jobsite and associated business and population density.
Materials, for projects with sufficient on-site storage, are delivered to the site and assumed to be available to workers as needed. If insufficient on-site storage is provided, then the project manager will need to stage the delivery of materials to the site. Experienced project managers consider the lack of on-site storage to be a major project constraint that should be explicitly modeled and managed. The first modern example of staging materials for projects was documented with the construction of the Empire State building. Having no space for on-site steel lay-down yard steel was delivered from the mill, still warm, directly to the construction site.
A material-related concern for sites that have sufficient space is that of optimizing the position of materials on the site so that they require the least travel time from the lay-down yard to the work-face. Materials should be moved around the site as little as possible, since moving materials for non-production purposes increases costs without any specific work result.
As a simple exercise to raise your awareness of this issue, find a local construction sites where brick walls are being constructed. Write down the date and location where the bricks are delivered. In some cases construction managers have seen brick pallets moved four or five times before the bricks are installed.
Logistics management and material lay-down yards are subjects of significant research efforts within the Construction Management community. The development of “lean-construction” methods addresses reductions in supply-chain waste. Technologies that employ Radio Frequency Identification (RFID) tags in lay-down yards have decreased material handling and reduced days required between delivery of and payment for materials.
equipment
There are various types of equipment used on construction sites. Some of this equipment should be considered in the project plan, some need not be included. Workers, and their companies, are typically required to provide the small tools needed to complete their specific features of work. This type of equipment is generally not included in the project schedule. There are some types of equipment, however, that can affect the overall sequence and duration of the project.
The most obvious example of a constraining resource, visible at large construction sites in every city across the globe is the construction crane. The installation and placement of cranes on the jobsite is critical to ensuring their maximum productivity. Project managers should seriously consider, at a minimum a milestone that includes the delivery and setup of large site-wide cranes.
Another type of equipment would be helpful to include in a schedule, particularly in highly constrained job sites, are work platforms such as scaffolding. Although scaffolding is temporary construction equipment that is not installed with the project, the presence of scaffolding at a particular work-face may constrain progress on activities below where workers are employed.
Resource Summary
Material, labor, and equipment are considered the primary three resources to be considered when planning a project. The main objective of considering these resources is to ensure that there will be no “surprise” delays as your project moves ahead. Many times you can include critical resource constraints, such as the delivery and installation of cranes, as individual activities in your schedule. Other times you may want to evaluate the impact of scarce resources or the impacts of workers moving on and off the jobsite. The next set of pages will assist you to consider these two questions: resource allocation and resource leveling.