Jim introduces the concept of the work breakdown structure (WBS), and describes how it is used to help plan the work to be performed at a construction project. He also discusses the correct method for creating a proper WBS.
- Sometimes, when a project is simple and it only contains a few specific work activities, it might be easy to visualize and to grasp the overall construction plan and process. I might not need a detailed schedule. Kind of like if I'm going to the store to buy three things that I know I need, I probably don't need a written list. But as things grow and get more complex, I need to plan first if I want to be successful. If I'm going to the store to buy meals for the entire family for the next seven days, I need to plan each meal and figure out what ingredients I need for each one of those meals and put them on a list, or I'm going to end up going back to the store five more times in the coming weeks to get the things I forgot or didn't know I needed.
Most construction projects are going to fall into this second example of being more complex. If your project has dozens or hundreds or even thousands of work activities, it's important the logic be carefully laid out so that all of the tasks are included in your schedule. I think the natural tendency here is take the approach of developing a schedule by starting with the first task to be performed, then adding the next and the next and so on until the last item is added.
This sounds reasonable and it sounds simple, but I'm going to tell you that this is usually the wrong approach to take on a construction project where there are hundreds of work activities scheduled. If you do it this way, you're bound to leave things out. You'll also run into parallel activities, things like site work going on outside the building while finish work is going on inside, and you ultimately will end up leaving things off the schedule because that sequential logic just isn't working. A better way to do this is start in the planning stage by using what we call the work breakdown structure, or WBS.
The work breakdown structure is really just a way of defining the entire scope of work on a project by breaking it into its individual components, and you do with this without any regard to when these things will be done. In other words, just take the plans and the specifications and start breaking down the job into what needs to be done. Again, don't worry about the schedule you have. Just define the tasks or the activities that you will need on the schedule. Start with the major systems or areas of work on a project, big things like site grading, off-site street improvements, foundations, structure, and so on.
Once you have those, start breaking each one of them down into greater and greater detail, focusing on each piece individually to make sure you include everything that's needed. Include the things that are on the plans and in the specification, and the things that are not. So what do I mean by things that are not on the plan? These are things that are needed during construction, things like safety considerations: installing guard rails on each floor of a structural steel building, or things like access considerations and crane set up.
These are all construction activities that are part of the project. They'll cost money and they'll take up time and resources. By taking each major component and breaking it down into those smaller pieces, you're much more likely to include everything. You'll figure out where it fits in the schedule later. Right now, you just need the work items or activities broken down. You want to continue to break these down into smaller and smaller items until you get into a work package that's a single, measurable piece of work that'll be performed by one entity in a single time period.
For example, if one of my starting items in the work breakdown structure is off-site improvements-- that's my big item-- I would need to break that down using the plans, and come up with things like demolition, removals, curbs, sidewalk, driveways, asphalt paving, lane striping and landscaping. I want to get to the point where I have each package as a defined and distinct scope of work that's performed by one entity, and each one should have a distinct start and end date.
This means that some of these things might need to be broken down even further according to phases so that they have that distinct start and end date. At this point, you might need more people involved. You may need to consult your field superintendent as you start getting more detailed and broken down into smaller packages. You may also need to consult the subcontractors on things like phasing. At the same time, you want to be collecting scheduling data like planned productivity rates or activity durations, and we'll use those later.
It's important to develop the work breakdown structure from the top down. Start with the project at that top level, and break it down like we've discussed in terms of phases, components, disciplines, functional areas, and so on, and just continue to do that and break it down into more and more detailed levels. Again, at this point, don't confuse this with the schedule, and don't try to put things in chronological order. Right now, you are defining and breaking down scope. You'll use this for many things as the project progresses.
You may use it to ensure you have each item assigned, and it can be used to more clearly define scope and assumptions. And like I said earlier, you will also end up with task durations that will help you with the schedule as we start to do that later. Let's continue, and I'll give you some simple examples of what this work breakdown structure might look like.
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