(1) Explain your problem, don't simply post "This isn't working". What were you doing when you faced the problem? What have you tried to resolve - did you look for a solution using "Search" ? Has it happened just once or several times?
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Hello,
I have just made my way into a precast production company as a project planner. My role is to plan the erection process at site. That is I have to plan which elements are to be erected on which dates and so on and my company wants me to do it in primavera itself.
I make the schedule considering each element as an activity and connect them with FS relationship. But the issue is once I have prepared my plan, sometimes due to external issues the erection does not go in the order which I want. Basically my activities have no proper order of execution. Order doesn't matter. Which is making it very difficult for me to plan in primavera. Any suggestions will be very useful for me.
Regards
Mohamed
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Hey all
Just a quick update. I would like to thanke everyone who has helped me here. I have been scheduling for past few weeks and its been going really really well. The managers are happy and I am happy as well. It wouldn't have been possible without this forum.
Cheers all!
Regards
Mohamed
Mohamed,
if you have some prefered order of activity execution assign manual priorities and the software will look at them first of all.
P6 users may select any combination of 25 activity fields in multi-level hierarchy for setting custom project leveling priorities. Trautmann and Baumann have tested 196 combinations on P6 and produced a “best result out of 3 rules” recommendation for Primavera software.
They recommended to perform 3 schedule runs with 3 different priority rules (A, B, C) and select the best result.
• Rule A: late start (1st), late finish (2nd)
• Rule B: late finish (1st), duration (2nd)
• Rule C: free float (1st), late start (2nd)
As of today I have never seen P6 to yield shorter duration resource leveled schedules than Spider Project optimization algorithm that requires no guessing on prioritization rules. P6 users are welcomed to challenge Spider Project resource leveling.
http://www.planningplanet.com/forums/planning-scheduling-programming-dis...
Hi, Mohamed.
The prioritization is of course based on your scheduling model.
To set the priorities, click shift F9
In this screen, you see at the bottom "leveling priorities."
Click Add
You see a screen with all the possible priorities.
Make your choice and level resources
That's it.
Regards Johannes
How do we exactly give priority? Please explain it a little. It's like I am stuck at the final point.
Hi Mohamed,
Resource allocation prioritisation can be done in many ways. You could assign the relations in the order you have specified yourselves.
The other options are to utilise the leveling option in the shift-F9 leveling option. P6 offers more the 20 options for prioritization.
My preference is to start with first option the early start, second, free float and as the third the activity leveling option.
Start with the most critical resource.
Trust this helps.
Regards Johannes
As far as I know I can see that the resources are being assigned in the order of activity ID. Help!!!
Hello all,
As suggested by some members here, I have done the scheduling based on resources with no relationship between the activities. I got a reliable schedule as output. It's been going well except for one problem.
When I assign a resource, say crew 1 which is doing the erection. I want crew 1 to finish activity A in WBS 1, go to activity B in WBS 2 then come back and do activity C in WBS 1 on the third day. But when I assign crew 1 to ativity A, B and C... it gets assigned to A first, then C and then B. This is because the resource is first assigned to WBS 1 and then to WBS 2. How do I change the order in which the resources are allocated to the activities? I dont want it to be based on WBS order. Does it depend on the duration of activity?
Please help
Regards,
Mohamed
Hello all,
As suggested by some members here, I have done the scheduling based on resources with no relationship between the activities. I got a reliable schedule as output. It's been going well except for one problem.
When I assign a resource, say crew 1 which is doing the erection. I want crew 1 to finish activity A in WBS 1, go to activity B in WBS 2 then come back and do activity C in WBS 1 on the third day. But when I assign crew 1 to ativity A, B and C... it gets assigned to A first, then C and then B. This is because the resource is first assigned to WBS 1 and then to WBS 2. How do I change the order in which the resources are allocated to the activities? I dont want it to be based on WBS order. Does it depend on the duration of activity?
Please help
Regards,
Mohamed
Thank you Rafael for all your suggestions.
Thank you all. I have been trying out different methods suggested here and a few of my own. It's been going well and I seem to be getting closer to a good scheduling method. Will keep it posted here once I start getting proper outputs.
Regards
Mohamed
In the end I would use annother approach as per following image.
Work on each axis is not driven by preferential logic as anyone can start in any order, they are driven by phase priority and if any chain is delayed no need to change preferential logic, adjusting priority order when need be should be enough making it a better model.
As you can see the alternate schedule includes 12 activities none longer than 10 days while your approach for such schedule would yield 50 activities per activity on proposed alternate schedule for a total of 600 activities, a nightmare to update. Is like scheduling a steel structure bolt by bolt, weld by weld, beam by beam ...
The alternate schedule is for the most simple case where a perimeter beam is pre-installed at all faces/axis, but this is not always the case, usually only axis in one direction will have the beam pre-installed while in the other direction you install the precast braced on the floor, the structural steel erector ties some elements directly to the wall and then you can finish with the removal of bracing and waterproofing.
I suggest a meeting with the general contractor, steel erector and precast subcontractor prior to preparation of the schedule to be agreed by all parts.
Be reminded that with such preferential logic you will have to fix out-of-sequence occurrences and adjust logic every time things do not go as planned, going back to the situation you initially asked how to avoid.
Not only at the installation do things might change, also at the yard it might happen that some special inserts for a specific panel were not available holding the production of the specific panel causing out-of-sequence progress and broken logic.
Another thing you might need to consider is that last segment prior to a corner is frequently measured afer all the others have been installed this to allow for installation as well as construction tolerances.
It is common for precast wall jobs be assigned a single crew and depending on size and precast details the crew shall install about 6 to 8 units per day on an 8 hour shift. At 6 units per day workload equals 1/6 of a day = 16.66 % or if using hous/day = 8/6 = 1.33 h/d.
Mike,
Thank you for your suggestion. That's exactly what I was planning to do. Now you have suggested the same as well. Then definitely I am going to try that out. Will update my progress once I get going.
Cheers
Regards
Mohamed
Hi Mohamed
Just a simple solution.
First set up your programme for production then do another for installation and ask the crew what sequence they are going to use.
Make the adjustments for the correct delivery sequence.
Best regards
Mike Testro
Thank you so much Rafael. Your last line, inspired me. Thank you so much for the motivation. All you guys inputs are surely going to help me someday.
Cheers!
Regards
Mohamed
Mohamed,
Usually a precast shop can produce faster than what the site crew can install so they can adjust their schedule to the demand of several jobs in parallel but it still must be scheduled / coordinated.
By years of experience depending on the precast details they can tell you the installation rate of precast panels per day and with this you shall make your installation plan.
It is not the same to install a single line of precast than installing several resting on top of each other. When installing precast on top of each other the lower precast will hold its own weight plus a portion of the weight of those on top until the shims are removed, this places some constraints on the sequence of installation.
Usually if a single story rectangular building, work will be coordinated by each of the four axis in a pre-agreed sequence and direction. Some pre-requisite activities will be done prior to start of installation while other will be done in parallel but hopefully before you get there, therefore the pre-requisite logic of work by others must be included.
Within a few months you will be able to teach us about all precast work scheduling requirements.
Good luck,
Rafael
If resources are unlimited then for installation just schedule all activities at the same time. Consider one crane and one installation crew for each wall segment. If 200 wall segments use 200 cranes, 200 installation crews.
For fabrication if 8ftx40ftx8in precast segment we have about 8cy per wall segment consisder one crane, one fabrication crew, one concrete placing crew and one conctrete truck for each wall segment.
Who said resorces do matter!
It is just 200 of these:
I dont think that resources is his problem
Thank you for your suggestions Vladimir. I will try out both in some minor projects and see which works out well. This is my first job and I am in pursuit of impressing my boss. Glad to get so much help will get back with the results soon.
Regards
Mohamed
Vladimir gave us another way to make the model and get similar results. I works pretty well when partial workloads is equal among all activities, and such is the case in this particular model.
As a matter of practicality at times some preferential logic must be used but when it can be avoided you will get models that will adjust execution order automatically based on a prioritization you establish.
I used constraints as to model a delay on a couple of activities and show how resource leveling will make the adjustments.
Mohamed,
Rafael suggested to use resource partial workloads but I am afraid that this is too complex for P6.
The same may be achieved if to create a resource Erection Crew, assign it to activities where it is required, set activity priorities depending on the preferred order of their execution and set Erection Crew availability. If the number of Erecetion Crew resources is 4 then only four activities can be done in parallel and other activities that require this resource will be delayed in resource leveled schedule.
Playing with activity priorities you can set and change the order of planned activity execution without creating and deleting activity dependencies.
First off thank you so much for the swift reply Zoltan and Rafael.
Thank you for your suggestions Zoltan. I will make sure to do my best to keep the schedule breathing. *wink*
Rafael, to clarify your suggestion, so I should create a schedule with no relationship logic, assign the available crews to each activity, give minimum number of elements per day, give a constraint finish date..... and then let resource levelling take care of the rest. Is that right?
DELAYED SCEDULE ACTIVITIES WP02 & WP03 - NO CHANGE IN LOGIC REQUIRED
UNLEVELED INITIAL SCHEDULE
LEVELED INITIAL SCHEDULE = Resource workloas 25% [max 4 activities per day]
You can take care of this issue if avoiding preferential links and use resource leveling for the installation crew(s) along with activity prioritization. If some activity is delayed you can take care of this if using date constraints. With partial workloads you can define how many wall panels can be installed per day. Then resource leveling will take care of the schedule considering the activities prioritization and date constraints.
Some overlapping of your activities along with other activities might be necessary to get an efficient plan. Usually there will be some scheduled sequence that will impact the temporary bracing sequence, access can be another controlling issue for the schedule so make sure everything is coordinated with the PM.
The last Marshalls Store I built had the precast panels laterally braced by a concrete on metal deck roof. Not all jobs are equal even when precast panels look similar.
since it is a precast production company there must be an order for which piece of precast becomes before another. If there are 10 pieces that fit together and are installed in a logical sequence from 1 to 10 you would not cast piece 10 before you would cast piece 1.
A schedule is a living and breathing thing that is constantly changing based on a whole lot of things and revisions will be necessary. Take your initial shot then make the revisions no software can help you with your situation.
Email: PPadmin@planningplanet.com
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