If I was in your situation, the first thing I would do is to find out the standard production rates for each major activity, for example Piling, We know that piling works is driven by the number of plant or piling rigs we have and these works are also subject to the ground conditions in your area or work place. You can find a lot of reference concerning production rates in the internet and you can adapt these rates but you need to evaluate the ground conditions in your area and another factor obviously depends on the skill level of the workforce available in your area.
Now, given that you have the manhours and production rates, you can now more or less calculate the duration, crew size and number of gangs you need, yuo may need to play around with the numbers to strike a balance and effeciency.
Best of luck.
Daniel
Member for
14 years 7 months
Member for14 years7 months
Submitted by gr*****@s***** on Wed, 2012-08-29 20:55
It is possible that somebody made those up as well - or simply made the numbers conform to what they expected/wanted. I think the answer is that without investing your time developing a spreadsheet and database or proposing that your company invests in a software license and database - both not bad ideas if you plan to continue in this industry - there is no simple answer to your question.
Who estimated the manhours in the first place? In order to do that means, he has a pretty good idea of the quantities involved and the standard production rates for each type of activity. What I am saying is that The information may already be exsting and you just need to ask or dig a little bit further. If you are the main contractor, then you need to look at the tender, review what were the assumptions and basis during the tender, the construction methodolgy and workflow, etc.
Thank you very much for your help and guidance. I have only one concern about RSMeans cost book that they provide data about commercial construction ( building, roads, bridges etc.). Do they have something about industrial plants construction? I am working on a power generation plant.
Regards
Naveed Raja
Calgary
Member for
14 years 7 months
Member for14 years7 months
Submitted by gr*****@s***** on Tue, 2012-08-14 17:50
Invest in the RSMeans cost book or an online RSMeans CostWorks subscription - they have a section with standard crews, if you lookup your operations you will find the standard crew used on North American projects.
Assume that crews are composed of four at a minimum, a leadman + 3 journeymen(possibly 1 is an apprentice) - this works as a 'step-multiplier' x4,8,12... to represent a realistic crew size stepping; ignore the equipment and haul trucks since they do not follow the crew size stepping unless the project is very large, for example there are 12+ excavators on-site.
Do what you are doing and complete a survey of industry practitioners - preferably those in the region the project will be completed in - to find what they use; when you are done, draw some conclusions about the patters in the data, publish a paper in an academic journal presenting your results and then put your data for sale online.
Also, you still need production rates, Duration = QTO / [(unit/hour) * crewSize:default=4 * #crews(adjust for 1:desiredDuration, 2: max# < local resources available) * ...lots of other factors * FactorOfSafety] or find a crew-based production rate
A shortcut: find your crital path, then what the driving applied resource is for those activities, and if those applied resources are limited, find the expected crew production rate for these - or do a time-step analysis and derive the production, the CAT handbook has tables to calculate equipment production, and fake-in the other activities so they fall in and assume they are crewed to the needed production. The cost: what if the critical path changes and now your schedule is based on data you madeup - probably as good as you can be expected to accomplish and even then better than most schedules.
Member for
14 years 7 monthsDaniel is right.
Daniel is right.
Member for
24 yearsNaveed,If I was in your
Naveed,
If I was in your situation, the first thing I would do is to find out the standard production rates for each major activity, for example Piling, We know that piling works is driven by the number of plant or piling rigs we have and these works are also subject to the ground conditions in your area or work place. You can find a lot of reference concerning production rates in the internet and you can adapt these rates but you need to evaluate the ground conditions in your area and another factor obviously depends on the skill level of the workforce available in your area.
Now, given that you have the manhours and production rates, you can now more or less calculate the duration, crew size and number of gangs you need, yuo may need to play around with the numbers to strike a balance and effeciency.
Best of luck.
Daniel
Member for
14 years 7 monthsIt is possible that somebody
It is possible that somebody made those up as well - or simply made the numbers conform to what they expected/wanted. I think the answer is that without investing your time developing a spreadsheet and database or proposing that your company invests in a software license and database - both not bad ideas if you plan to continue in this industry - there is no simple answer to your question.
Member for
13 years 3 monthsDaniel, Crew size and mix
Daniel,
Crew size and mix have not been mentioned in the estimate. They have only man hours and cost.
Regards
Member for
24 yearsNaveed,Who estimated the
Naveed,
Who estimated the manhours in the first place? In order to do that means, he has a pretty good idea of the quantities involved and the standard production rates for each type of activity. What I am saying is that The information may already be exsting and you just need to ask or dig a little bit further. If you are the main contractor, then you need to look at the tender, review what were the assumptions and basis during the tender, the construction methodolgy and workflow, etc.
Best regards,
Daniel
Member for
13 years 3 monthsForest, Thank you very much
Forest,
Thank you very much for your help and guidance. I have only one concern about RSMeans cost book that they provide data about commercial construction ( building, roads, bridges etc.). Do they have something about industrial plants construction? I am working on a power generation plant.
Regards
Naveed Raja
Calgary
Member for
14 years 7 monthsYou have three optionsInvest
You have three options
Also, you still need production rates, Duration = QTO / [(unit/hour) * crewSize:default=4 * #crews(adjust for 1:desiredDuration, 2: max# < local resources available) * ...lots of other factors * FactorOfSafety] or find a crew-based production rate
A shortcut: find your crital path, then what the driving applied resource is for those activities, and if those applied resources are limited, find the expected crew production rate for these - or do a time-step analysis and derive the production, the CAT handbook has tables to calculate equipment production, and fake-in the other activities so they fall in and assume they are crewed to the needed production. The cost: what if the critical path changes and now your schedule is based on data you madeup - probably as good as you can be expected to accomplish and even then better than most schedules.