Sub critical paths

Hello Francis

In addition to what Gary said, you should have defined what your critical path is... using planning software (e.g. P3) you could define it as "TF less than 0","TF equals 0", or most likely the longest path in your schedule..

Cheers!

Christian

Hi Gary,

As you told, sub-critical path is the additional parallel path which is having duration less than the critical path....

Then my query is whether sub critical path’s end date will determine the project’s finish- or in any way is it influencing the project’s finish?-What will be the total float of the activities in th esub critical path?

As the case in my project, 3 critical paths are there, one through the tower, podium and testing & commisioning-all the 3 having total float eaual to zero,

Cheers,

Francis Varghese

Primavera 5.0 is capable of calculating multiple float paths based on Total or Free float.

Hi Francis,

Critical path is the longest continuous path of the project, which decides the project duration. (Hence the activities of this path have zero total float). If mutiple paths in the network happens to be of same length/duration, then there can have multiple critical paths in the project.

But ideally in the baseline programme we keep only one critical path by re-planninga ctivites. However, during the monitoring stage we can have multiple critical paths, becasue of delays in activites (once an activity reaches or crosses its late dates, it becomes critical).

I think sub-critical path shud be something like secondary critical path - the network path just shorter than the critical path. Hence it cannot have zero float, but the float will be the difference of its length from the critical path’s length..(bcos, this path can afford to delay till critical path finishes!)

regards
Sonia

My understanding is that critical path is normally based on zero float. Not familiar with sub-critical paths. But my logic says it should be quite close to zero, depending on our own definition...can be 1 day float, 2 days, etc...

In the good old days (in my case 1980-early 90’s) we used to calculate the critical path by hand using the forward and backward pass. Simply put, where Early Start/Early Finish = Latest Start/Finish, this was the critical path. By definition the ’path’ was unbroken and float = 0.

There are one or two points here. The first is that it is always a good idea for the planner to be able to work out for him/herself what the cp is. Believe it or not, the computer does not always give the correct answer!

Second, beware as some software packages determine that an activity without a successor link should be treated as critical - check your settings.

Third, why can’t a programme have more than one cp? If the project discussed here were let to 3 contractors to build the 3 towers, we would have 3 cp’s. In this particular instance, however, it depends on the timing and the resource issues, in other words if all 3 buildings are to finish at the same time and there is no commonality between the buildings then there will be more than one cp. If however, the timings are different or there is a movement of resources from one to the other, then the reality is likely to be 1 cp for the project, but several for the contractors construction programmes.

At the end of the day planning is to some extent about being creative and thinking outside of the box, so don’t let yourself be constrained by the ’there can only be 1 cp’ mode of thinking. After all hasn’t anybody here built the roof before the walls before?

David

based on the adopted definition of the critical path (i.e. zero float), then it is definitely possible to have more than one critical path for a particular project.

Hi,

Another factor that influence critical path are the constraints, specifically mandatory constraint.

As much as possible, constraint shall not be use, in this way a free flowing logic can be generated including the critical path.

On the other hand milestone constraint imposed by the client during tender stage shall also be highlighted. Generally, the milestone constraint from the client incoporate liquidated damages clause. As a consequence, this milestone must have a mandatory constraint.

In the build up of your schedule, you will notice progressive critical paths, multiple critical paths due to mandatory constraint impose by the client.

Cheers,

Charlie

Hello Clive,

What you are saying is the ambience in Hong Kong.

What I’m trying to expound was based on my experience as tender planner, on-going construction planning engineer (Start to Finish) and as forensic planner invovled in claims.

I know what im trying to say because i have been involved in different phase as planning engineer which some are not in the same position as mine.

Remember: Planner Omno Universale - The Universal Planner the ultimate Quest.

Cheers

Charlie

Hello Clive,

This is the best idea I encounter for this week. I will recommend this to be the best idea of the week and hopefully will remain the best idea of the month.

The essence here is that the free flowing of logic should be the first exercise to be made. As much as possible the planner should not be influence by his pre-judgement that this so and so activities will be the critical path based on the project the planner did years back.

This approach is very important to young planners within PP to have the patient in developing proper free flowing logic analysis.

Cheers,

Charlie

yeah I’m also confuse with that matters....anybody there give some direction for that subject

IMO, there’ s no sub critical path.
the "Path" is not really a path like a road from one end to the other end.

critical path is just a collection of critical activities (based on you set up, logic, contraints, resource, float...)no matter where these activities are, on a single path or multi-path

And if resources, financing and supplies have limitations then critical activities may be not linked at all.
Subcritical activities have small resource constrained floats.