Activities that have positive total float can be delayed the amount of their respective total float value without delaying the project. Activities that have negative total float are already behind schedule. The Primavera P6 Gantt chart automatically displays the activity early dates, but it is possible to display a activity late bar on the Gantt chart to visualize the effects of both positive and negative total float.
Primavera P6 Professional displays the early start and early finish of activities on the Gantt chart. To help determine how much leeway you have in progressing your activities it is also possible to display a late bar definition on the Gantt chart. This late bar definition displays your activity’s late dates.
This article demonstrates how to display an activity late bar on the Gantt chart to help better understand schedule flexibility.
Our demonstration project schedule is displayed in Figure 1.
Note, in particular, the constraint on ‘Dig Cable Trench’, Figure 1. This constraint is generating three days negative total float on ‘Dig Cable Trench’ and several upstream activities.
Note the total float column and the respective negative float activities, Figure 1. You will also observe that several activities have positive total float. It is possible to decipher the effects of both the positive total float and negative total float by inspecting the late start and late finish dates in the activity table. But wouldn’t it be great to visualize the effects of both the negative total float and the positive total float directly on the Gantt chart.
It is possible to display late activity dates directly on the Gantt chart by defining a ‘Late Bar’ using the Late Bar option in the Bars dialog’s timescale column as seen in Figure 2 below.
Note the normal filter and bar definition preview, Figure 2. When this ‘Late Bar’ definition is toggled on, the Gantt chart appears, as per Figure 3.
Not only does this Gantt chart display that ‘Grade Site’ and ‘Install Conduit’ can each delay, but it also warns that ‘Dig Cable Trench’, Mobilize, and ‘Set Foundation’ are already behind schedule.
Note: if you do not have a “Late Bar” defined in your Bars dialog, you can create one using the Add button in the Bars dialog and setting it’s attributes to equal the ones you see in Figure 2. See our blog Creating Custom Activity Bars in Primavera P6 Professional for details about creating custom bars.
The Primavera P6 Gantt chart is a powerful visualization of the project schedule. Yes, it is possible to tabulate the late start and late finish of activities. But displaying the activity late dates directly on the Gantt chart provides greater insight into schedule flexibility. Using the late bar timescale it is possible to create a ‘Late Bar’ definition that will graphically depict the effects of both positive and negative total float on your schedule.