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Scheduling a Housing Project (600 Villas)

7 replies [Last post]
Ali Murtaza
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Joined: 19 Aug 2015
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Hello Experts,

I will really appreciate if someone can help/guide me with scheduling strategy for the following query:

Question:

I have a project of 270 Villas having different types as follows:

Type 4 = 255

Type 6 = 15

As per client's requirement WBS for construction of villas will be block wise as follows:

BLOCK 1 = 39 Villas

BLOCK 2 = 39 Villas

BLOCK 3 = 39 Villas

BLOCK 4 = 39 Villas

BLOCK 5 = 39 Villas

BLOCK 6 = 39 Villas

BLOCK 7 = 36 Villas

Set of activities for each block will be same as for one villa.

Now the problem is,

1. How i should calculate the duration of my activities for each block?

2. What should be the links of activities?

Hope i have explained good. If further information is required please ask. Thanks in advance for your usual support.

Replies

Rafael Davila
User offline. Last seen 5 days 8 hours ago. Offline
Joined: 1 Mar 2004
Posts: 5227

If backhoe can be moved at any time between the Villas and Blocks then it is a regular renewable resource and any resource leveling should be able to take care of the issue.

On the other hand if backhoe is to be captured by a group of activities then it is a Spatial Resource, unfortunately P6 cannot handle this scenario by means of resource leveling while Spider Project can.  You are stuck with hard relationships if using P6 and every time you are to re-schedule you shall re-consider these links.  To make it worse combining soft logic and hard logic as a mean to force resource leveling is tricky and can lead to wrong models.

http://www.pmknowledgecenter.com/node/104

Spatial resources are required by a group of activities, rather than a single activity as renewable resources. The spatial resource is occupied from the first moment an activity from the group starts until the finish of all activities from that group.

http://www.mediafire.com/file/nz4rvig3on6ums5/Presentation+-+Consumable+...

http://www.ronwinterconsulting.com/Reviewing_Resource_Leveled_Schedules.pdf

Constraints. The schedule should not mix constraints, soft logic, and resource leveling for any given resource, especially for critical resources. A resource leveled schedule can be turned into a CPM schedule by adding date constraints or soft logic but this is not recommended. Mixing the methods at the same time reduces transparency and accuracy. It can be very difficult to discern if the soft logic used is interfering with the optimum solution for resource leveling.

Ali Murtaza
User offline. Last seen 7 years 4 weeks ago. Offline
Joined: 19 Aug 2015
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Hello Mr. Rafael, Thank you. Excatly you are right, if we make this hard logic to link one block activity to next block...if delay occur in one block the succeeding will delay unnecessarily. So please suggest what should be the approach?? We are using primavera it is clients requirements also.
Ali Murtaza
User offline. Last seen 7 years 4 weeks ago. Offline
Joined: 19 Aug 2015
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Hello Mr. Mike, Thank you. If we use one excavator for block of 39 villas, then it will take 78days (39villa x 2days )to finish excavation of one block of 39 villas. So the duration of each activity in the block will increase right? And, the relationships will also required to be change...may be start to start.... Please suggest...
Rafael Davila
User offline. Last seen 5 days 8 hours ago. Offline
Joined: 1 Mar 2004
Posts: 5227

This is a classical example of how a poor practice it is to replace true and temporal resource dependencies with hard logic.  This is an approach suggested by those whose software is not good enough at modeling real life resource leveling scenarios such as consumable and spatial resources, variable quantities and workloads resource leveling just to name a few.

http://www.pmknowledgecenter.com/node/104

What a schedule logic mess if you add an excavator or increase/decrease the availability of other resources?  Most all of these hard links will no longer be valid, the same goes with other resources. 

What if for some reason Block 3 must be delayed 6 months?  Hard logic will delay Block 4 unnecessarily. 

What if there is a change in availability of some spatial resource such as elevated slab flying forms? Most all of these hard links will no longer be valid.

A good planner/scheduler using capable software should take care of it at a single click of the mouse.

There are missing sitework activities, do not overlook them.

WHAT A MESS!

Mike Testro
User offline. Last seen 1 day 18 hours ago. Offline
Joined: 14 Dec 2005
Posts: 4418

Hi Ali

Zoltans answer is correct but he missed out the phasing.

You have 39 villas all requiring excavators so the excavation task is each linked FS so only one excavator is deployed.

Use the same method for all ther trades so if you have 3 gangs of block layers then you link every third task FS.

The other thing to consider is the start sequence.

After the access roads are in place and the drains and services are in place then you start at the back and work outwards. This enables the finishing paths and lanscape to follow from the back to the front.

Best regards

Mike Testro

Ali Murtaza
User offline. Last seen 7 years 4 weeks ago. Offline
Joined: 19 Aug 2015
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Dear Zoltan,

Thank you for speedy response.

Lets talk about Type 4 Only as most of blocks have Type 4 Villas.

I have developed the schedule model for Type 4 Villa (Single Unit) with practical relation (Mostly FS).

Now if i placed all these set of activities (created for one villa only) under Block 1 of 39 Villas, it means all the 39 Villas are starting together at the same time.

For example:

Excavation = 2days in my schedule model, it means  the 39 villas have excvation work in these two days, means 39 excavators are required.

Therefore i am confusing how to link and assign durations.

Either it should be same as for one unit or different relation / durations for a Block.

Zoltan Palffy
User offline. Last seen 19 weeks 4 days ago. Offline
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you need to create a typical detailed sequence for Type 4 villas and another typical detailed sequence for Type 6 Villas

and you should link similar activites if you have a manpower constraint