Schedule Development – Construction and Schedule Management Services

Construction Scheduling. Do you have a Schedule or a CPM Schedule?

Is what you’ve created a CPM schedule? Or is it a schedule with dates and activity bars?

Can you tell the difference?

First, CPM stands for Critical Path Method and is kind of a general term often used for Precedence Diagram Method, PDM schedule development.

Almost any schedule developed, using one the many current scheduling software programs, will be created based on the precedence diagram method. Most of the current scheduling software programs are set up for that.

Creating the WBS structure or summary bars and adding activities that model the work for the project in these programs will produce a schedule.

But is this really a useful schedule? Or is it a list of activities with dates assigned through the use of incomplete logic and date constraints? We get a list of activities with planned dates. That’s all we need, right? Isn’t that a schedule…?

Not really. That may be useful for conveying the basic plan for future work. But this is not a dynamic CPM schedule that can be used to model future work based on current progress, produce a Longest Path, or model the impact added or delayed work may have on future completion dates for the project.

I run into this a lot. A PM or someone on the project team will create a schedule and assume it is a CPM schedule. There are a few requirements to meet before a schedule can be considered a true CPM schedule.

Listed below are the minimum requirements for a CPM schedule.

Calendars.

For your schedule to be reasonably accurate, calendars need to be created to allow activities to have durations based on planned work periods. This usually requires the development and use of multiple calendars to account for various work periods such as 5-day 8-hour workweeks; 4-day 10-hour workweeks; workweeks with specific holidays set as non-workdays; anticipated non-workdays due to anticipated weather impacts….

Logic.

The only activity without a predecessor should be the first activity in the schedule. Usually NTP. The only activity without a successor should be the last activity, usually Project Complete or CCD… To be a true CPM schedule, all activity dates should be driven by the predecessor activities durations and logic. Having only all the predecessors assigned is not enough. There must be activities that are driven by the start or finish of a predecessor activity. If the activity in fact, does not drive the start of any work except the end of the project, then the successor should the last activity.

Constraints.

There are valid uses for date constraints in any schedule. However, overuse creates multiple interruptions to the forward and backward passes which determine float values. This produces snippets of paths based on the types of date constraints. Just using a constraint to set a planned start date for an activity is not a valid use of a date constraint. An interim date constraint should represent an external driving force for an activity or milestone or the contractually required date for a milestone. Limiting the use of date constraints allows the activity durations and activity relationships, (logic) to drive finish dates and produce a Longest Path to the finish of the project. This gives us the Critical Path for completion of the project.

Relationships and lags.

There valid reasons for using SS and/or FF relationships to model the planned sequencing of activities. But they should not be used in lieu of decomposing the work. Using SS and /or FF relationships should only be used to model work which will run concurrently even when the work is broken down to a reasonably small duration. Lags should not be used to model work or a waiting period. Lags are not transparent and using a lag with SS or FF relationships results in the work being modeled to start or finish based on a set time after the driving relationship has been satisfied, not on actual measurable work being complete to a specific point.

These are the most basic requirements for a CPM schedule.

The idea is to end up with a schedule that will model the impact actual progress to-date has on remaining scheduled activity dates. A CPM schedule can be used by the project team to proactively manage current schedule slippage, more accurately manage resources, and project finish dates and time-scaled cost flow.

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. CPM Schedules for Government Construction Projects.

You’ve been successful in winning a government construction contract. Maybe it’s a project administered by a Federal agency like the United States Army Corps of Engineers or the Veteran’s Administration. Maybe it is a state agency. At any rate, if you haven’t started developing the project’s Baseline Schedule, now is the time to start.

The place to start is the CPM schedule requirements from the RFP docs. Although they may be found in different sections, almost every agency has CPM schedule requirements in their contracts. They all vary, but they are usually much more stringent than the commercial CPM schedule requirements most contractors are comfortable with.

Are you prepared to develop your baseline schedule while meeting these more stringent requirements?

There are usually limitations on the duration for work activities. There can be requirements for activity coding which you may not be familiar with. You need to understand how to develop project-level calendars, resources and activity code.

A CPM Schedule Consultant with experience developing and managing these types of schedules is a valuable resource for you. Even if you plan to keep your schedule work in-house, having an experienced CPM schedule consultant available for advice and mentoring is a good bet.

There is nothing magical or overly difficult about meeting the CPM schedule requirements, but it can be costly in terms of time and aggravation if you have to keep correcting the baseline schedule when you’re unable to get owner approval. You will have your hands full getting the site safety plan or accident prevention plan accepted. There is also the Quality Control Plan. These administrative submittals and other early submittals and subcontractor buy-out will keep your PM team tied up for the beginning of the project. A little help with your schedule development will relieve the pressure of getting all the required preconstruction work completed so you can start mobilization and doing the real project work.

And most importantly, you must have your baseline schedule accepted to be able to develop your first progress update and submit your invoice.

The key is paying attention to all the detailed requirements. These agencies usually enforce conformance with these specifications. The development of calendars, the special activity code structure, the method of assigning resources and cost, and the use of constraints are all spelled out in great detail.

Don’t be afraid to reach out for help. There are many CPM schedule consultants with plenty of experience working with these CPM schedule requirements. Find someone you’re comfortable with and let them take some of the burden from you….

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. Developing the Project Schedule Plan.

When you’re bidding a project, do you start developing a schedule plan? Or plan your schedule?

Before we ever start developing activities, we should plan the project, and this includes planning the schedule.

We need to determine how we plan to sequence the major portions of the work, establish required and preferential phases, break the project down into smaller deliverables based on area, CSI code, sub-contractor, type of activities – contract milestones, procurement, administrative activities…

This information is probably part of the cost proposal development process and provides us with the building blocks for developing the WBS.

We also need to have an idea of what type of activity calendars and coding we will need to use. The resources we will need to develop can be based on the subcontractor or CSI deliverable list.

As a CPM Schedule Consultant, I use this information to develop a schedule plan. I use this plan to develop the project WBS, activity coding, resources, and project calendars. I develop these before I ever start creating the activities for the schedule. Having the WBS developed helps ensure we have the entire scope of work in the schedule. Having the activity coding developed allows me to assign these items to the activities as I create the activities. This helps with filtering and sorting to assign hard and preferential logic and for reviewing work for specific resources or subcontractors for trade stacking and for reviewing specific areas for trade congestion. It’s just easier to assign the Responsibility and CSI activity coding along with assigning the resources. This saves time and avoids mistakes. Having the calendars developed helps with setting the original durations once we have all the logic assigned.

Planning the project as well as the schedule is the important first step in developing the project schedule.

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. Is the Schedule a Complete Schedule? (For Owners).

Do you review your Baseline Schedule to make sure all the work to complete “The Project” is included?

Are you sure?

When the contractor develops the schedule, they should be planning the project execution first. This includes the phasing of the project, the necessary permits, the long lead submittals, the procurement of subcontractors, equipment, and material, the close-out of the project, and the actual work necessary to build the project.

Often, we see schedules which do not include permits, or the procurement of long lead items, or complete commissioning, testing, and inspections. Let’s not forget the closeout requirements for as-built documents, warranties, or training, (if required).

The CPM schedule should include all the work necessary to execute the project. An easy way to ensure all the work is included is to make a list of all the closeout deliverables and compare that to the WBS for closeout section of the schedule. The same for special inspections, commissioning. For whatever reason, we always look closely at the construction section of the schedule, but tend to gloss over the administrative, procurement, and commissioning sections.

Just as we look at constructability for the project plans, we need to thoroughly look at the project schedule to make sure all of the deliverables are included. And, the activities to provide these deliverables need to be complete and broken down into sufficient detail to control the work!

An activity at the end of the project schedule that says “Finish Project” is of no use. All the activities necessary to actually plan and control the post “Substantial Completion” work for the project should be as detailed as the construction work is. The same for the commissioning and testing of systems.

And, let’s not forget the initial administrative requirements which have to be fulfilled prior to starting any work. We usually need an approved Safety Plan, an approved environmental permit, and building permit at a minimum. The time to develop these, get them submitted and reviewed and approved needs to be in the front of the schedule.

Also, we need the long lead time equipment or material submittals in the schedule. I also like to have the main materials submittals, in general form, in the schedule just to make sure we get them in and reviewed in time for their use in the project. Often, the contract documents state the required review period for the owner. We use this for the review period in the schedule.

There should be a fabrication and delivery activity(s) for any major equipment which should drive the start of any installation of the equipment. This activity(s) should be driven by the submittal and procurement of the equipment. Often, this will drive the Critical path.

Everyone tends to really look at the construction activities. As Planning and Schedule Professionals, we need to look at the project deliverable as a whole.

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. Too much Detail.

When we develop the Baseline CPM Schedule for a construction project, we need to develop the WBS to establish the project deliverables.

To what level of detail is this required?

The general idea is to decompose the project deliverable down to the Work Package level. For construction, this could be taking the WBS down to an area of structural foundation for a large project. It is really taking the deliverable down to the point that it can be easily identified and measured.

We then develop the “work” activities that need to happen to produce this deliverable.

Basically, we develop the list of activities, sequence them, assign the resource(s) and determine the Activity Duration, and assign the activity’s Budgeted Cost. There are also the Activity Code, Calendar, and Role assignments…

Many specifications have limits on the number of Work or Calendar Day duration a “work” activity may be assigned. A good rule of thumb is “not to exceed the reporting period”. I like to cap my “work” activities at 20 Work Days or less. An activity should only have one responsible party performing the work. If an activity only has one party performing the work and the duration of the work is going to exceed 20 Work Days, perhaps it is best to break the work area down to allow smaller durations. It is difficult to accurately measure the performance of activities with large areas or durations.

The use of activities with large Activity Durations also leads to the use of Start-to-Start and/or Finish-to-Finish relationships to model the work which is now running concurrently with other large duration activities. This should be limited. The overuse of Start-to-Start and/or Finish-to Finish relationships is a basic problem for many detailed project schedules. Makes a pretty Gantt Chart, but does not allow adequate control and measurement of scheduled work.

Most deliverables should have activities with durations much less than 20 Work Days. They should not all be 1 Work Day unless that is actually what it takes to model the work of several parties. Usually, the “work” could be broken down to 5 days to excavate the foundation, 2 days to install reinforcing steel and any vapor barrier or blockouts, and 1 day to place concrete and an activity with a period of time for concrete curing. Breaking the work down to this level allows the work to be easily measured and managed. Too often I see a “Place Foundation Concrete” activity with a duration of 10 Work Days. No cure activity. No idea if cure time is included or not…. No idea when the excavation should complete or when the reinforcement placement starts…. Most likely, the formwork and reinforcement work will run concurrently at some point and the concrete placement will be driven by the finish of the reinforcement work and inspection. If there is a delay in delivery of reinforcement steel, we should be able to accurately model that…..

The idea is to develop a schedule which is manageable and has enough detail to control the work. Pretty simple.

If there is more than one contractor performing the work, you probably need to break down the work further. If a series of activities are all running concurrently, perhaps it would be best to break the work down into smaller areas. The goal is to use Start-to-Start and/or Finish-to-Finish relationships as little as possible. Using Finish-to-Start relationships is almost always the best way to model the work. This usually requires breaking the work down into smaller pieces…

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. Contract Duration and the Finish Date.

When we develop the Baseline CPM Schedule for a construction project, we need to know the contractual dates for Beneficial Occupancy, Final Contract Completion, and any other contractually required dates for deliverables.

The calendar day difference between NTP and the Required Contract Completion Date determines the project duration in Calendar Days.

Various organizations use various names for these required dates. There is NTP for Notice to Proceed. This can be for design, construction of any segment of the project. In construction, it is usually for the start of construction, but Design-Build projects typically have NTP for Design and even interim NTP dates. The names for Contract Completion vary greatly. Beneficial Occupancy; Start Operations; Contract Completion Date; BCOM…. The list is long.

Whatever the terminology, we have to end up with a project schedule that fits into this period of performance.

We develop the schedule based on input from all stakeholders. We verify we have included the entire scope of the project. We make sure we sequence the work in a constructible manner. We use accurate durations for work activities.

Does the Project Schedule then report a finish date which meets the contractual requirement?

More often than not, it does not. Correcting this is another issue.

So, what drives the contractual finish date? Is it a business decision based on a valid business need? Is it an organizational need for a change in operations? Is a specific date to meet some public good?

Many times, the contract completion date has been established based on someone’s best guess to create the period of performance. Sometimes, the Capital Projects Team decided on the period of performance based on another similar project. Sometimes funding issues drive the period of performance.

Whatever the reason, the project must be completed within the period of performance or some type of punitive action will result. This is just one more reason to develop a robust and dynamic CPM schedule with which the Project Team can manage work proactively. The effort expended to create and manage a quality CPM schedule is easily recovered with the savings gained through improved management of work and adherence to the required finish date. Whatever it is called…..

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. Activity Codes and Organization.

When the schedule is developed, how do we determine the Activity Coding for each activity?

What is an Activity Coding Structure?

Many PM’s don’t know or care about the Activity Coding. Unfortunately, they are missing out on the use of a great tool.

I’d like to offer several reasons for spending the time and energy to develop and use Activity Coding.

Activity Codes are developed for the schedule based on specification requirements and a Schedule Management Plan. It can be as simple as a specific assignment for phasing. More often an Activity Code Structure is developed to include specific phasing of the project, responsibility for work, areas of work, CSI assignment, weather sensitive or not, and type of work.

I like to develop the schedule Activity Code Structure prior to building the activities out. I usually do it when I set up the calendars, resources, and WBS. After all, it is based on the plan for organizing the schedule and reporting for the various stakeholders. It is also used for schedule analysis.

Once the Activity Code Structure is set up, (Along with the calendars and calendars, resources, and WBS) we can start building out the activities for the project schedule.

If you develop the string of activities for a specific trade, which is how I usually start out the development of each trades’ work, it is easy to assign the resource and activity coding as you assign the activity calendar and resource. By having already established the Activity Code Structure, there is already a ready list of choices. This prevents inadvertently assigning similar coding for the same item.

So, we develop all the activities by WBS with the appropriate activity calendar, resource and Activity Coding.

Now we can sort and group in a multitude of ways based on the Activity Coding Structure we planned and executed.

We can group by responsibility and sort by Start Date if we have already assigned the logic. Or we can sort by Activity ID if we added the activities sequentially in the order of execution. This makes it easier to manage adding the logic. We can then group by area to see how we need to coordinate the work between trades. This is very handy for establishing preferential logic.

We most often use the Activity Coding for Layouts and presentations.

Grouping the schedule by phase and then area is a popular layout.

We can also filter by responsibility which allows us to analyze the planned sequence for each trade and verify scope. If the logic is complete and there are many activities planned for the same work period, resource allocation may be an issue. This layout allows us to assign preferential logic to assign resource flow.

There are many reasons for developing a robust Activity Coding Structure. We use them often and they offer a great method of organizing the activities for analysis.

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. Activity Durations and Unicorns.

When the schedule is developed, (after the project has been broken down and organized into the WBS and the activities have been developed to support the deliverables), how do we determine the duration for each activity?

How do we accurately determine the work period for each activity?

There are several ways this task is approached. Some are better than others….

I believe we can all agree that knowing the required work quantity and production rate per day is the best input we can have to accurately calculate the duration. How often do we actually have that much detail?

More often, the project team determines the durations based on their “feel” for how long the work will take based on similar work from the last few projects. This is not necessarily a bad thing. This is historical data and is very useful.

The problem is that we tend to be optimistic. The larger the piece of work is, the more difficult it is to accurately determine the duration, by “feel”.

Typically, the activities are all developed based on input from the project team, the constrained finish date is applied and then the schedule is “calculated”. Usually, we do not make the required finish date.

Now we start crashing the schedule to pull the finish date back.

We’ve all seen videos of buildings constructed in a week and other supernatural feats. So, it stands to reason that we can build anything within any timeframe, right? If the owner wants the project by the date in the contract, we have to crunch the schedule until it shows we can deliver on time.

As we know, a very high percentage of projects do not finish on time. This often leads to claims and poor performance reviews.

Is it possible that we set our projects up for failure at the very beginning? Do we assume we can provide a finished project within the contract duration just because the owner has specified the period of performance?

If the schedule is constructed using “most likely” durations for all activities with reasonable logic and the project is then constrained to finish on whatever date that produces, there is still a good chance the project will finish late. It could finish early, but that seldom seems to happen.

If the durations are based on pessimistic durations, the project will still tend to use the time allowed leaving little room for problems towards the end of the project.

If we place a contingency activity at the end of the project, we can work towards an early completion hoping we magically finish on or ahead of time.

Or, we can put the effort into building very detailed schedules with solid logic and durations and then execute the projects per the schedules, as well as possible.

Any way you slice it, a poor schedule does not work. An aggressive schedule is not realistic and will soon fall apart, a pessimistic schedule will also fail due to a lack of aggression to complete work.

A detailed schedule, with input from all team members, does not guarantee success, but it does provide a realistic path to get there. It is up to the project team to execute based on the plan. But they can’t do that without a solid schedule.

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. Critical Path and Total Float.

Can the Critical Path for a project have different Total Float values?

Does the Total Float value determine the Critical Path?

When the Baseline Schedule is developed, all the activities should have the appropriate calendars, durations and logic applied. This creates the schedule network of activities.

Within this network of activities, there are many paths which run through activities linked by mandatory or “hard” relationships. For example, the structural steel shop drawing development and submission should drive the review of this submittal which will then drive the procurement with lead time to drive the delivery and then the erection. Almost all the trades and materials have these “hard” relationships which form the work sequence for that network path.

There are also discretionary or “soft” relationships. For example, the ACT grid could be installed prior to the wall painting. I prefer to run the grid after the walls are painted, but it may be necessary to install the grid first to allow light fixture and register installation to start earlier. This may be sequenced at the discretion of the Project Manager or Superintendent.

There are external relationships, but these are usually handled within the schedule itself. But it is possible to link activities in one schedule to work in another schedule….

Once all the mandatory and discretionary relationships are assigned, and the calendars and durations are assigned we can “schedule” the project. This is what sets the schedule network up.

This is what also determines the Longest Path and Total Float values.

If there is not a finish constraint applied to the project, the end date will float dependent on the network. The Total Float value will be 0. If you sort the activities by Total Float value and look for the next continual sequence of work activities with a Total Float value close to 0, you will most likely find the Near Critical Path. Just be aware that this Near Critical Path is based on the Total Float values only and will not necessarily be the logical Near Critical Path.

If you have a constrained finish date for the project, the Baseline Schedule should have a Total Float value of 0. But as soon as you start updating actual progress, the work will force the various network paths to push or pull and this will change the Total Float values. The Longest Path will still be the Critical Path, but the Total Float values may be positive or negative values. Again, the next continual sequence of work activities with a Total Float value close to that of the activities on the Critical Path should be the Near Critical Path, based on Total Float values only.

Recognizing the Critical path is the Longest Path is the basis for properly managing the work. Recognizing the usefulness of the Total Float values for identifying Near Critical Path work is also valuable.

This is a fairly simple concept. But, there are many discussions about what determines the Critical Path.

Not using Longest Path as the definition to use Total Float values is a tool we use for analysis. Much as we use Progress Override instead of Retained Logic for analysis.

Interim Constraints play into the schedule network and affect the Longest Path and Total Float values. But this is another subject for the future….

I’m sure many of you have additional insight into this subject and can help explain the concept. Please share!

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP

Construction Scheduling. What are the Critical and Near Critical Paths? Why do we care?

When the schedule is developed, the schedule logic should be complete. All activities should have at least one predecessor and one successor, with the exception of the first and last activities for the schedule.

If this is done, the combination of activity durations, activity calendar assignments, and schedule logic create the CPM schedule network. This CPM schedule network is made up of many sequences (logic paths) of activities.

In simple terms, the longest continual path from the project start to the end of the project or the next hard constraint establishes the Critical (Longest) Path.

The Total Float values are a just the product of the forward and backward pass through the CPM schedule network. Just because the Total Float value is zero does not make the activity critical.

However, the Total Float values are important. If the Critical Path has a Total Float value of zero, then the Near Critical Path activities will most likely have a Total Float value very close to zero. I say most likely because the activity calendar assignment has an impact on the Total Float values. But often, this is a simple rule of thumb for determining the Near Critical Path. I like to keep an eye on work that is on the Critical Path first and then also pay attention to work that falls on the Near Critical Path(s) within one or two weeks of the Critical Path for large projects and a few days for small projects.

It’s not unusual for the PM and Superintendent to focus on work on the Critical Path and not pay enough attention to work on the Near Critical Path(s) and then have the Critical Path shift because a lack of progress for the Near Critical Path work took over the Critical Path.

This is just one reason complete logic, calendar definition and assignment, and limiting constraints are important when developing a baseline CPM schedule. If you scatter constraints throughout the schedule, you will not have a true Critical Path for the project. Without complete logic, you do not have the means to accurately complete the forward and backward pass that establishes the CPM schedule network scheduled dates and Total Float values. Without calendar definition and proper assignment to activities, durations will be erroneous and this will ultimately produce a false schedule network.

I know many of you can offer additional comments and recommendations. I welcome your comments and input. My goal, as always, is to help our industry and help the projects we support….

I’d love to hear what you think!

Please visit https://conschmanservices.com to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP