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Hi friends,
I hope that everyone are healthy.
I'm trying to model a truck flow to a new estimate to a bid.
In a construction, I have many trucks with many materials to be delivered ( gravel, sand, concrete, asphalt and so on) coming and going every day for ten hours shift, but I have only one guardhouse to controle this flow, this is a main constraint of my schedule, because fatally we will have a bottleneck because of this. Each truck takes 5min to pass on guardhouse, so we only have 12 trucks per hour at maximum flow, no more. Based on the brief above, does anyone have a model with a similar situation, to help me? I can't find a valid solution to this model. The construction is an airport and usually has many restrictions to get in on the site. Best regards, Daniel Morais
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Hi Renzo,
You're right, thank you for your contribution.
Best Regards,
Daniel Morais
Dear all:
it is nice how you solved the problem.
Just to complement, the "bottleneck in the guardhouse" is a typical Queuing theory problem (the mathematical study of the delays of waiting in line, considering from arrival time to the number of servers).
On the web you can find a lot of material about it.
regards
There is some parameter that I forgot?
best Regards,
Daniel Morais
I reproduced the same scenario and I don't arrive at the same result, do I samething wrong? look below please:
Look the information of reason of delay to "activity delivery 6", 49703.2696...days???
best Regards,
Daniel Morais
Daniel,
It is from previous file but with variable quantity and interruptable for Delivery 6.
Best Regards,
Rafael
Great Rafael, thank you.
The example is from the same file sent previously?
Best Regards,
Daniel Morais
If some activity can be scheduled as Interruptable and with Variable Quantity you might reduce project duration while increasing the average number of deliveries per day.
Best Regards,
Rafael
That the maximum is enforced it does not mean it will always happen 8 hours per day and every day will happen the maximum number of trips.
On the other hand you can calculate how many trips per day, please see following illustration. You can generate a tabular schedule diagram, while other reports can get you more granularity. With multiple calendars and activities starting/finishing at mid-day it can become difficult to follow, but the software will get it right.
Best Regards,
Rafael
Hi Rafael,
Analysing the file my thought was confirmed, this way the quantity of the resources by hour are correct 12 at maximum, but per day should'nt be 12 by hour x 8 hour per day = 96trips? By day it shows the same 12, per week too...
I don't know if we have a solution by this, maybe this model should be the best we can do it for this situation, what you think?
Best Regards,
Daniel Morais
Hi Rafael,
About the second model (renewable resources), is more applicable, I did a same approach but I have a doubt if the maximum trucks by hour would be different by day, 11/hour, 88/day and so on. Can you share this file please?
best Regards,
Daniel Morais
Hi Rafael,
Thank you by your first model (spatial resources), he is smart and it works, the problem is because we have many many interations by day, weeks and months depending of the volumes and quantity of activities can be it can be very arduous to work in this way. For the few activities like your example of "elevated slab forms" is fantastic, but with many flows of in/out like trucks doesn't good in my opinion.
Consider using renewable resources. The use of Spatial Resources for a single activity might be an overkill.
Consider the Guard House as a Spatial Resource. Thoug it can do the job it is a bit (or shall I say very) granular.
Will follow with a sample Spider Project model.
Email: PPadmin@planningplanet.com
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