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. Use of Relationship.

When your contractor develops the project baseline schedule, do they use many Start-to-Start (SS) or Finish-to-Finish (FF) relationships? Do you know?

A relationship determines how the successor activity will start or finish relative to the predecessor activity. The most common relationship is the Finish-to-Start (FS) relationship. The scheduled finish date for Activity A determines the scheduled start date for activity B. Unless a lag is assigned, this is simple. (See previous post).

However, often the schedule model requires the use of SS and/or FF relationships. If the activities will actually run concurrent and the activities are broken down to the level of detail necessary to plan and manage the work, this is acceptable. If the relationship includes the assignment of a lag, it may still be acceptable but this relationship should be reviewed and agreed to by all parties.

The problem arises when the series of work activities is developed with SS relationships and there are not any successors to the finish of these activities. These are essentially open ended relationships which means the activity could not finish and still not affect the schedule. This may indicate the work is not developed to enough detail to allow Finish-to-Start (FS) relationships to drive the work. Or the addition of work driven by the activity was missed during schedule development. If this work happens to fall on the Longest Path, this path is now driven only by the start of work for each activity, not by the finish of the work for the activity. In time, these relationships may fall on the Longest Path through updates and out-of-sequence work. personally, I prefer to limit the use of SS relationships in general.

Then there are the Finish-to-Finish (FF) relationships. These force the successor’s scheduled finish date to push out to follow the predecessor’s schedule finish date. This is commonly used to close off SS relationships to model concurrent work with the finish dependency. However, often the only successor is the FF relationship. This creates an open finish, which is much like a missing successor. If the predecessor has only the finish of the concurrent activity to drive, and this relationship is a FF relationship, and the successor has no other predecessor. It effectively has no predecessor to the start of this work. If the predecessor activity has only the successor with a FF relationship, what future work does it drive?

Finally, there is the combination of relationships that create reverse logic. Activity A is a FF to Activity B. Activity C is a SS to activity B. The duration of activity B determines when activity C can be scheduled to start. The start of activity B is not driven by any other work. The finish of activity B is driven by the finish of activity A. If the duration for activity B is increased, unless the start of activity C is driven by another predecessor relationship, the start date for activity C is pulled back to schedule an earlier start. This can have unintended consequences for the schedule. We see this often when the schedule is developed using a lot of SS and FF relationships.

We won’t mention the Start-to-Finish (SF) relationship. This is extremely rare. This says that the start of a predecessor cannot start until the finish of the successor. I have only seen it used intentionally and with an acceptable reason twice. And that was to model work on a rolling wave schedule for which there was not much design detail developed. However, this relationship is sometimes used by mistake.

The SS or FF relationship, if used correctly, can allow the schedule to model the plan. It is my opinion that the use of these relationships should be kept to the absolute minimum and be only used to model actual planned concurrent work which is broken down into the level of detail necessary to plan and control the work.

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

Construction Scheduling. Use of Relationship Lags.

When your contractor develops the project baseline schedule, do they use many relationship lags? Do you know?

A relationship lag is an imposed period of time between the predecessor and successor activity. A common use in a Start-to-Start (SS) relationship with a 2-day lag. Perhaps the contractor’s plan is to start finishing drywall 2 days after the drywall installation begins. This allows the work to run concurrently.

There absolutely are times when work can and should be modeled this way. However, care should be taken to ensure an open start isn’t inadvertently created. (This is a future topic)

The problem arises when the series of work activities is developed with SS relationships with an assigned lag. This may indicate the work is not developed to enough detail to allow Finish-to-Start (FS) relationships to drive the work. The issue is, once the start of the predecessor is actualized, the start of the successor is only dependent on the calendar set for use for lags. This may not match the number of days intended. If this work happens to fall on the Longest Path, this path is now driven by a calendar. I prefer to limit the use of SS relationships in general, much less with assigned an assigned lag.

Then there are the Finish-to-Finish (FF) relationships with lags. These allow the successor work to finish only after the predecessor’s finish date plus the lag duration. This is commonly used to close off SS relationships to model concurrent work with the finish dependency. However, often the only successor is the FF relationship with the lag. This creates an issue in itself. (This is a future topic)

The most serious issue is when the relationship is an FS with a lag. What does the lag model? Should there be an activity to establish this difference in the relationship finish to start? Most likely, the answer is yes. There is nothing wrong in using an FS with a lag to have the lag represent say, cure concrete. I personally prefer to add the cure concrete activity with the number of days required. This is more transparent. The lag is not visible and creates a non-work period seen in the Gantt Chart bars and can cause confusion.

Then there is the negative lag, or leads. Many schedulers like negative lags and use them as a viable way to model the plan. When I see an FS relationship with a negative lag, I wonder why the use of a SS relationship with a positive lag could not have been used. The use of the negative lag may better represent the thought that the successor cannot start until 3 days prior to the finish of the predecessor. And this 3 days is the critical period. I personally prefer to model this type of plan with a SS with a lag or to further break down the activities to allow the use of FS relationships to model the work.

Finally, there are the SS relationships with an assigned lag that is larger than the activity duration forcing the model to show the work as an FS relationship. Why not just use the FS relationship? Unless there is a reason to model the work this way, it just doesn’t make sense to do so.

The relationship lag, if used correctly, can allow the schedule to model the plan. It is my opinion that the use of lags should be kept to the absolute minimum and only used to model SS or FF relationships.

But remember, the lag follows the calendar set for use for lag calculation. If the predecessor calendar is set for use, and the predecessor is assigned to a 5-day work week calendar, the lag will follow that calendar and the duration will be in work days. So, a 3-day lag could become a 5-day delay between the relationships if the lag spans a weekend. This may not have been the case when project work was planned and the schedule was developed and the lag did not span a weekend. Remember, this is not transparent, only someone who understands the schedule software and has access to the native file format can verify this. Unless the schedule layout includes the columns which show relationships with lags and the column that shows calendars. Even then, you need to know what the actual non-work days for the specific calendar are.

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

Construction Scheduling. Resource and Cost Loading the Schedule

person-question-300x300Once you have the basic CPM schedule development completed and you’re ready to start resource and cost loading, do you find the schedule specifications lacking in requirements or guidance for this part of the schedule development?

Some schedule requirements simply do not require resource or cost loading. Some require the assignment of resources but do not speak to cost. Some allow simple lump sum cost loading, some require unit pricing with equipment and material costs broken out.

Whatever the case, most of us prefer the schedule be cost loaded, at least the baseline schedule. This allows us to create the performance measurement cost curve for EVMS and the early and late cost curves many of us are familiar with and most specifications require.

Each planning and schedule professional will have their own preferences for resource and cost loading the schedule.

Myself, when a lack of requirements allows, I prefer the resource and cost loading be kept simple. Unless the payment process for the project is based on unit prices and crew pricing, I avoid unit pricing with equipment and material costs broken out. I work mostly in mid-size construction projects and find that lump sum cost loading works just fine.

One thing I prefer is to keep my percent complete type set to physical and make the cost percent complete equal the physical percent complete. I find this works well if the delivery of large equipment is cost loaded and work activities are assigned cost which includes labor, equipment and basic materials. Simple to develop, manage, understand and track. Remember, this is for general construction. Road, UG infrastructure, and other linear unit driven schedules will benefit from unit pricing.

I also like to assign a resource for each subcontract, even though I lump-sum cost load. This allows a resource or cost curve for each. This helps with resource level analysis.

I believe resource and cost loading of schedules is an underserved discussion topic and our industry as a whole would benefit from learning how various industries and project types approach this process.

Hopefully, this post will help start some dialogue among us.

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. Problems Modifying header and footer variables in Primavera P6 version 15.2?

CPM Consultant Professional Project Management
Project Management

It seems that there is an issue with Primavera P6 version 15.2 that makes it “impossible” to modify the variables for the header and footer sections.

This had me stumped too. But I found a work- around.

You can still add the variables by selecting modify and typing in the variable you want. Such as [cd] for current date or [filter_list] for the filters used or [project_name] for the project name…. There are commands for most all of the variables. I don’t have a complete list, but the common variables I use for most layouts is listed below.

Data Date:                    [data_date]

Project ID:                   [project_id]

Project Name:             [project_name]

Layout Name:             [layout_name]

Filter List:                   [filter_list]

Current Date:             [cd]

Page:                         [page_number]

Pages:                       [total_pages]

What other methods have you found to work around this issue?

Does anyone have the full list of commands?

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. Are you Including the Complete Project Scope in the Schedule?

person-question-300x300When you begin the planning for your project schedule, are you defining the project scope and breaking it down into work packages? Do you ever discover that work may have been missed if you had not completed this exercise?

You are not alone.

It’s just so easy to take off and start building the activities to build the project. It’s already in our head and all we need to do is get that plan on paper. Right?

I’ve found that even for a simple project, it makes the schedule development much more effective if the project team goes through the process of breaking the project down into the basic work packages and cross checking with the bid documents. This is often when we discover some piece of the scope is not included in any bid package. It happens….

This is why planning is a very important part of the schedule development. During the planning process, the work packages are developed, the sequencing of the work package delivery is worked out, the coordination of the work package execution is worked out… The list goes on…

I like to work through the planning process and then develop the WBS for the project schedule. This helps me determine how to develop the activities that create the deliverable work package and also helps with the preferential logic to coordinate work packages and resource usage.

The planning process is also a good place to develop the project calendars, activity coding, and resources. I like having these in place before I start developing the activities. It makes it easier to make the assignments as I go and keep the momentum of developing the work flow going. Having to stop and create a calendar or activity code breaks my flow. I also hate going back and trying to make calendar or code assignments after all the activities are developed. Some activity coding is simple to assign, but activity coding for responsibility, area, level, or CSI is more difficult to go back and add. That’s my story and I’m sticking to it.

The process of sequencing the activities and assigning the durations is easier for me then too. I can compare similar work through the use of activity coding. I can also use the resources I assigned early to make cost loading easier.

What other methods have you found to plan and develop your project schedules?

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. Are you using Calendars Appropriately in Your Project Schedules?

excalmation-markDo you understand the need to develop specific activity, resource and project calendars? So you put the effort into this process? Do you understand how calendars can help you?

Many, many smaller projects have project schedules with calendars that are set to whatever the default calendar setting is. Typically, this is a 5 day work week calendar with 8 hour work days.

You may ask, what is wrong with this?

Well, the short answer is, you are not allowing your schedule program to effectively schedule the work for you. You should really have a calendar for each different work week, such as a 4-10 hour day calendar, (if you have a resource working this shift). A 7 day work week calendar with no holidays is very helpful for project milestones because the total float is in calendar days. A typical work week calendar with defined holidays and anticipated weather related non-work days is a great way to ensure weather sensitive activities have anticipated “weather days” assigned.

For this post, I will only talk about activity calendars. Resource calendars can add complexity, and must be addressed, but not in this post…

For activity development, I prefer to keep things simple. I use the appropriate calendar, based on the planned work week for the work tasks. This includes holidays and any other don-work days identified in the contract. I develop a weather day calendar, based on the appropriate normal work week calendar to assign to my weather sensitive activities. I use a 7 work day week calendar, with no holidays or any other non-work days for my contract milestones and as the default for the project. This allows the team to see calendar day total float values.

Of course, the use of multiple calendars creates a little confusion when reviewing the schedule. The total float values for a string of activities will be different based on the calendars assigned. The actual start date to finish date durations will not match the “work day” duration assigned. These types of issues confuse many people. But once you use the calendars appropriately, you are letting the schedule better model your plan for the work.

Isn’t this what the schedule is supposed to be used for at its’ most basic level?

What other methods have you found to model and manage work with calendars?

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. How do we Incorporate the Subcontractor’s Schedule in our Baseline Schedule Development Process?

Road signAs construction scheduling professionals, we’ve all developed project baseline schedules. We’ve also worked with our subcontractors to get their input for the schedule, often with less than stellar results…..

This seems to a common problem. Continue reading “Construction Scheduling. How do we Incorporate the Subcontractor’s Schedule in our Baseline Schedule Development Process?”