Jim explains that once the activities with float time have been identified, the process of finding the critical path in the construction schedule becomes easy. Jim explains the importance of recognizing activities on the critical path, and notes that this is also called the critical path method (CPM).
- With our somewhat lengthy previous discussion about early and late start and finish times, and how to calculate float, the discussion on identifying critical path becomes easy. Actually, I already defined it in the last video. Any item that has no float, is on the critical path. Any item that shows an early start date as being the same as the late start date, means it has no float. If it starts late, then the project end date will be affected, and that means the activity is on the critical path. So, what's the big deal? Well, it's really important on a construction project to identify items on that critical path, and to recognize that if these items don't start and finish on time, the overall completion date will be affected.
You do not want to ignore this early on, and then find yourself at the end of a project facing liquidated damage fees that the owner's going to deduct from your payment for not finishing on time. When a critical path item starts or finishes late, you have to make adjustments or accept the probability that the job will finish later than shown on your schedule. That's one of the reasons that I talked about including procurement and management items on the schedule, because often times these will be in the critical path, so you don't want to overlook them.
Likewise, when we have items that are not in the critical path, we may be able to focus a little less of our attention on them because they have some float. This can be really helpful to know when you're trying to balance limited resources like manpower. If an activity with 20 days of float started 10 days late, you probably don't need to worry about making adjustments to crew sizes, or working extra hours to make up for starting that activity late, because you still have some extra float time to use up, before that activity impacts the schedule.
So far in all of these discussions, I've just been using the terms time and days and durations, but now that my network model is done and my critical path is identified, it's time to move to that last step and turn those days into actual dates on the calendar.
This course identifies the steps needed to develop a proper plan, and demonstrates how that plan is transformed into a construction schedule. Throughout the course, instructor Jim Rogers shares examples of his own successes and failures in the areas of construction planning and scheduling, so as to lend real-world context to the concepts he covers.
- Types of schedules
- Planning versus scheduling
- Work breakdown structure
- Developing a schedule
- Creating a network model
- Assigning durations, costs, and resources
- Identifying the critical path
- Letting the software do the calculations
- Checking and updating the schedule
- Scheduling's impact on productivity