Common Techniques for Construction SchedulingAssociation of Construction and Development
November 16, 2012 — 4,710 views
Common Techniques for Construction Scheduling
Whether a project is big or small, new construction or a re-build, mapping a construction schedule is a key component of successful progression. It forecasts when each step of the process will occur, how long each step will take and in some cases the cost. Once building begins, everyone starts with the same information and expectations.
Four basic scheduling techniques are commonly used. The simplest is the bar chart. It graphically represents the list of activities that must be accomplished, designates start and completion dates and states the length of time each will require. Aside from being uncomplicated to generate, it is straightforward and easy for most people to understand, which is critical when communicating with site foremen and sub-contractors. Unfortunately, bar charts fail to adequately provide detailed analysis of the project, don’t lend themselves to updating and fall short on ensuring efficient use of time.
A second construction scheduling technique is the critical path method. More detailed than the bar graph, it lists more activities and shows how they are interrelated. Primarily, it spells out which activities must be completed and/or started in order for other activities to be started and/or completed. A drawback of critical path scheduling is that it must be constantly updated from the smallest level of detail as the project goes forward and time projections shift. This attention to detail requires man hours and resources.
The line of balance technique is ideal for construction work that is repetitive in nature, such as house building. This type of scheduling focuses more on allocation of resources for each activity and less on time. By identifying and procuring the resources needed for each stage, no one activity will hold up the completion of any other. Line of balance is not useful for unique construction projects.
Finally, Q scheduling is a form of construction management that addresses the sequence of activities and the relationship of those activities to each other, as well as the cost of finishing the job. It takes into account the overall construction site and prevents two competing activities from occurring at the same time in the same location. It also streamlines repetitive activities in the same way as the line of balance schedule. Though many consider this method to be closest to reality, it requires specialized software and can bog a project manager down in the cost analysis of the multitude of schedule alternatives generated.