Primary Resource

Mike,

I would like to add that schedules are dynamic, that you shall manage the schedule and no fixed model shall tell you.  Very frequently as the job progress an activity that was not critical such as could have been the case in my example. If it becomes critical then it might be that lowering the minimum amount of masons required to make the crew is an option among the many others.  

If the software is to be Best in Class it shall help with all scenarios in a similar way the experienced manager would do it.

The assumptions about volume of work and productivity shall always be transparent instead of a Black Box.

Best Regards,

Rafael

Mike,

You said - The benefit is in resource modeling where the production rate of the volume of work determines the duration of the task - balanced by the gang size.

This means to model the following scenario you shall provide the software with the basic information:

1- The volume of work - 8,000 CMU [Concrete Masonry Units].  If for some reason you find out the volume of work changes to 10,000 CMU you simply change this quantity in your model, same as if other quantities do change.

2- Resource Pool: 6ea Mason1, 8 ea Mason2 and 10ea Mason3 

3- CMU Resources Production rate - say we are talking of concrete masonry unit it would be something like, Mason1 300 CMU/day, Mason2 275 CMU/day and Mason3 250 CMU/day.

4- The Gang Size - from 8 to 12 CMU Masons for the activity in question, final gang size  and crew production rate will be calculated based on availability as there can be several gangs working several activities at the same time.

Obviously if at any given time there are 8 available masons you are not going to delay the start of the activity until there are 12 available, it might be weeks latter and by that time the activity would have already been finished.

Am I right? This is how it would be managed at the site and this is how it should be modeled. I do not see other way that would make sense. It is very simple math performed everyday at the jobsite. 

Best regards,

Rafael

Hi Vladimir

I agree that "Primary" and "Driving" are synonimous in respect of resource modelling.

I am surprised when you say that P6 does not have a resource modelling function where the task duration is calculated by the ratio of work volume and production rates balanced by gang size.

That is a fundamental requirement.

Best regards

Mike Testro

Mike,

I like your comment but want to add that it is possible to have several driving resources in the same crew.

If, for example, two different excavators (with different productivity and cost) dig the same hole both are driving.

Activity duration is defined by the volume of work and total productivity of all assigned resources. If rsource is non-driving then its productivity is zero.

P6 does not have this functionality (volumes and productivities), so I expect that adding driving resource to the crew may change activity duration for certain activity types, adding non-driving shall not change the duration for any activity type.

Regards,

Vladimir

Hi Moutaz

The benefit is in resource modelling where the production rate of the volume of work determines the duration of the task - balanced by the gang size..

In a mixed trade gang the modelling is appled to the primary resource.

Best regards

Mike Testro

Hi Moutaz,

This price is used to compute cost for any activities with resource assigned.  In general, Cost = Budgeted Units x Price/Unit. Now, if you do not have price assign to your primary resource it means it will give you any value in your budgeetd cost. While in Materials you do have your budgeted cost value perhaps in accordance with your BOQ.

Cheers,

Arnold

Hi Moutaz

A primary resource is the one that is driving the output - in a mixed gang of 3 masons + 1 labourer the masons are the primary resource.

Best regards

Mike Testro

Dear Moutaz,

A primary resource must be a labor resource only and it does not apply to nonlabor as well as material resource type. Price is not an issue in assigning primary resource.

Cheers,

Arnold