Line of balance

Hello Anderw,

I found an article about The application of Line of Balance (LOB) method in construction projects using Excel tool. I think it would be usefule for you: Line of balance

There is nice excel sheet you can download also in the same article above.

Mike,

Very rarely a schedule is 100% linear, even those who at certain WBS level are linear will require the details to get the schedule data.  We show on the linear chart only linear phases and use the Gantt View for all work along with several other views to get deeper understanding of the schedule.

Anyone can arrange the bars using a WBS or Activity Codes based on location for a clear view of when activities on same area happen at the same time.

When using SS & FF links with same lag, preferably volume lag, the bars will never cross each other, a very basic concept for planning linear work, a basic concept you do not understand as you insists on FS links only. With the SS-FF same lag relationships you make sure lines do not cross but it is with resource planning, taking into consideration resource production rates, that you can get a good resource plan with minimum of interruptions.

I never worked on a linear job where the main resources; equipment such as scrapers, backhoe, bulldozers etc. were unlimited [each with different production rates] resource leveling along with planning for continuous work was always required. Balancing the crews and overall work was always a basic question.

Providing the site a LOB Chart without the resource plan is not good enough.

Best Regards,

Rafael

Mike, clashes do not mean that the schedule is wrong!

Crossings mean problems with scheduling of some types of work and do not create any problems for others.

You can build the road and do something on the roadside at the same kilometer and at the same time.

You can perform railroad tracklaying and install sytem equipment at the same point of the tunnel length that is used as Location metric.

So crossing shall be studied but it does not mean that every crossing represents some error.

And if you discover an error it means that your model missed some restrictions. I agree that Time-Location Charts may show that the model is poor. But if it is good everything will be OK on both Time-Location and Gantt Charts.

Regards,

Vladimir

Hi Rafael

What your time line chart shows is that your green and yellow tasks clash in the same location at the same time - that is the main purpose of the display.

You cannot see it in the bar chart.

Best regards

Mike T.

LOB Diagrams provide so little information that at times not even for a single activity diagram they will show enough details. The following figure shows how for a single activity the diagram display the same production rate throughout the duration, it even shows production rate during week ends.

I only use them as to showcase how little information they provide, you cannot ask for more from a summary chart. I do not spent time creating a chart with a bunch of such summary lines.

The following shows a typical time location diagram with a few more lines.

I use multiple WBS and Gantt at a high WBS level for this purposes and expand to see the details, something you cannot do on LOB Only software.

Hi Gents

We are all saying the same thing in different words.

Execpt you cannot do a LOB view in P6.

Best regards

Mike T.

LOB is one of many ways to present the schedule. The schedule is the result of calculation based on the data in the project model. These data shall be entered in some forms. If the same parameters are entered then it does not matter if the result of project scheduling is shown as LOB, Gantt Chart, Network Diagram or just table. LOB is nice but it does not include everything that may be needed for schedule analysis, so it is necessary to be able to use other views too.

Wherever you look for LOB on the Web it talks about resource and resource production rates. The following link is one example of such references.

http://www.mosaicprojects.com.au/WhitePapers/WP1021_LOB.pdf

1. They all talk about the need to balance the resources. I agree.
2. They all talk about how easy are to interpret the chart. I agree.
3. Some say CPM is incompatible to LOB. I disagree.
4. Most do say it can provide same level of details with less point, or I shall say less detail. I disagree

• Any CPM schedule can be drawn in LOB charts, no matter if linear or not, if not linear the fit will not be good and only if you define a line for each activity it will make sense. They assume within each line all activities are balanced as to have same time/location slope. On linear jobs you target for it but it is not always a good choice.
  • I would not be surprised if Asta generates the LOB from the CPM in a similar way Spider do. You level and syncronize the activities production rates using the CPM and then define how they will be summarized on the LOB Chart. The lines are not drawn from the air.
• The same level of details, no way, it is not the same but a summary.

Hi Rafael

Asta LOB system does not rely on resources but replicates the Tilos image where a task is set in a combined time / location 2 dimension matrix.

It starts with a task bar for a location with a bar code allocated

Then each task in that location is set down and each one coded - this is not possible in P6 having multiple tasks on one bar.

Then in the LOB window you select the bar codes and then the task codes and the LOB view is diplayed under the gannt chart.

You can display the LOB on a full screen view.

You can add resources but they are not the driving factor.

Best regards

Mike T

With a Crayola set you can paint any meaningless line you want, line of balance is all about resource allocation and their production, the lines are a summary of their output.  If you are using software without considering resource production rates you are drawing sloped lines as if a skewed bar chart drawing.

The whole idea is to create a balanced schedule that considers resource allocation and production rates. Line of balance diagrams are only a graphical representation of your schedule, usually in a summary form but does alone does not gives you the necessary details.

I do not find much value on drawing a few sloped lines that do not tell me about resource production rates and how they are allocated as to get the "balance".  When dealing with LOB models Lags shall be defined as volume lag because as the resource allocation varies, the production rates vary and so the time necessary to keep the distance.  Software that specializes on LOB charts at the expense of resource allocation that considers resource production rate are of not much help.

Hi Andrew

Asta PowerProect does have a line of balance facility which works well on linear projects such as roads - pipelines and housing estates.

I has to be in mutiple tasks per line mode - each task with an indiviual code.

The trick is in correctly coding the Bar Line which gives the location and then each task which generates the LOB view.

Resource allocation is not the primary requirement to generating LOB in Asta only the task duration when resoutce modelling is applied.

I use it often as a reliable alternative to a Time Chainage chart such as Tilos.

Best regards

Mike Testro

Andrew, LOB is just another way of presenting project schedule. So it is the same schedule that may be shown in the Gantt Chart, Network Diagram or in the Time-Location Chart. In any case you create the same project model with the same resource constraints. If the model is correct then the schedule shall be correct too.

There's some basic infomration at: http://www.mosaicprojects.com.au/WhitePapers/WP1021_LOB.pdf 

For housing / units google 'Location Based Scheduling' and Prof. Russell Kenley of Swinburne University - its his area of expertiese.