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Man-Hours

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Aytek AKTAŞ
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Joined: 10 Jan 2011
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One “man-hour” is one hour of one worker. If one worker can pour one 1 m3 concrete in 15 hours, then 1 m3 can poured in 15 man-hours. Theoretically, with three workers working, one m3 conrete can be poured in five hours.

Spent Man-hour

Spent man-hour is the actual man-hour spent on site during the execution of any given activity.

Planned Unit Man-hour

 “Planned unit man hour” is defined at the beginning of the Project, and provides the man-hours required to perform of one unit of any given activity.  

 Earned Man-hour

Earned man-hour the result of the formula where the actual installed quantity for any given time period for any given activity is multiplied by Planned Unit Man-hour. The Earned is used for progress calculations and shows the man-hour that would have been spent to install the “actual quantities” if the planned unit man-hour would have been the same as spent man-hour. Unit planned man-hour and site actual quantities are needed for calculation.

Planned Man-hour

Planned man-hour is the total man-hour for any given activity and it is the result of the multiplication of Planned Unit Man-hour by total quantity. If there is 10000 m3 concrete to be poured at the project, then the planned man-hour is 15 man-hours / m3, then planned man-hour for concrete works are 150.000 man-hours.

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Rafael Davila
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Joined: 1 Mar 2004
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By keeping same quantity of resources but by varying their productivity you are keeping constant the amount of resources but the projected duration of the activity will change, therefore there is no linear relationship here between quantity and duration. In addition the driving resources can vary as you change composition of the crew. Yes resource production is not always a linear function, usually it is not, it is more complicated.

Take for example an earth moving crew of one excavator with a capacity of 100 cm/hr and 8 trucks with a capacity to move dirt at a rate of 10 cm/hr based on the average round trip of one round trip per hour. The crew capacity will be limited by the amount of trucks to 80 cm/hr. If you increase the amount of trucks to 20 the crew production will be limited by the capacity of the excavator 100 cm/hr.

What MR Weaver is calling for I would say is always present, download the PDFs and keep them for future reference.

Patrick,

Thanks for the reference, keep posting these, they are valid no matter what software you are using.

Best regards,

Rafael

Patrick Weaver
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There is absolutely no direct relationship between the quantity of work, crew size and durations.  The total fallacy of this concept was clearly demonstrated by Frederick P. Brooks Jr. in his book, The Mythical Man Month first published in 1975 (I’ve got the 20th anniversary edition from 1995).

To actually understand what’s involved in setting durations see: