How to propotionate Man power / trade

Hi Saju

The short answer is that you can't do it with any degree of accuracy.

You must split the RCC tasks into sections such as Slabs - Columns - Walls - shafts then break each section down into seperate tasks for Rebar forms and pouring.

Then you can allocate the different resouces into the respective tasks.

This is called bottom up planning and is the most accurate and responsive form of planning that there is.

Best regards

Mike Testro

I do not agree with the following statement with regard to the splitting each section into separate tasks for rebar and formwork. 

"You must split the RCC tasks into sections such as Slabs - Columns - Walls - shafts then break each section down into separate tasks for Rebar forms and pouring."

I have seen very poor specifications that requires you to keep the crews on different activities simply because the specified software lacks good resource loading functionality. The following figure illustrates how bad this practice can be. At times it will work as intended such as for Slab A but at times it might not such as for Slab B. As your job progress this can get worse, it might happens no single pair of activities happen in parallel.

I agree resource loading on concrete pouring requires a separate activity.

"It is simple, if you keep the incidental works under separate tasks they might not be scheduled by the resource leveling to happen on parallel even if using SS and FF relationships."

Resource leveling breaks the CPM relationships?  What software does this?

Hi Bernard

All of them that applies resource levelling correctly.

Thatis why I never use it.

Best regards

Mike Testro

hi

how can i update,

for eg:in my program having six zone

for electricai duct

total no is 1212

setting out&formation(25%)-300 completeted

shuttering and concreting(65%)-274 completed

backfilling(10%)-20 is completed

with regards

siddeeq akbar

Resource leveling breaks the CPM relationships?

No it is just the traditional CPM calculations will not keep the activities together.

Just model the sample job using any software and you will find out the activities you expect to occur in parallel might not occur as expected, it is enough for at any given time the lack of resources delays the incidental activity using FS and FF links, not to say if using a single link. If this happens then the predecessor should be delayed as to occur in parallel but this is not how CPM model works. 

The following figure will give you the data for availability and assignment of resources plus the logic required to make the model using your software.

Note there are 2 form slab crews while there is only one reinforcing steel crew.

Using Spider Project you can model the schedule using separate activities in combination with strict links as follows and will yield expected results on this simple schedule. I doubt MSP or any Primavera product has such functionality but it wold be interesting to run the test. 

Still I am reluctant to use strict links because they apply to resource leveling only and it might be that at some point some non driving logic link becomes driving a condition that might break the "strict" link delaying the successor but not keeping the predecessor in parallel. I play it safe and keep the crews assigned to a single activity and use the strict links functionality with much care only when assigning the different crews to the same activity is not feasible.. 

It is true you can work it out correctly but single activity is safer. In addition if you transfer the model to other software lacking strict links functionality it might spell disaster. Another issue is that strict links are limited to a single outgoing link per activity and in the case you need to model more than two related crews it will not make it. This can be solved bu linking SS related activities in tandem instead of one to many but can be error prone if not done with care.