Working Time Calculation – Calculate man hours. Calculation of the labor required to execute a reinforced concrete base.
In this example, we calculate the hours worked for the construction of a reinforced concrete foundation.
Working Time Calculation – Construction Work
Description of the Base
The base to be built has the following dimensions:
- Height 0.50 m.
- Length 3 m.
- Width 2 m.
- Quantity of reinforcing iron 300 Kg.
The foundation has a volume of 3 m3, with a quantity of 100 kg of iron per m3 of concrete.
In this construction work, a semi-automatic concrete plant on the site supplies the concrete.
Image of the Base Under Construction
The following figure shows the filling process of the structure already with formwork and reinforcement in place.
This calculation excludes the time required for excavation, clearing and backfilling of the soil.
Table summarizing hours spent
Example of direct labor. Table with the number of labor hours consumed to build the base.
Working hours according to the table to make this base:
30 Mhr + 4.5 Mhr + 14.28 Mhr = 48.78 Mhr.
We must correct this value, adding the variable times specific to each job.
Other Times to Consider
If applicable, we must add times for:
- Labor consumed by moving the equipment and materials to the site of the base.
- Labor for layout and control.
- Times for depression of the phreatic layer if it applies.
- Labour hours for excavation and subsequent filling of soil.
- Labor for executing the cleaning concrete.
- Direct labor for curing, dismounting, and cleaning.
- Labor added if we build the base within an operating plant.
Here, we consider that the location of the construction site is isolated and the execution of the work is independent of another plant in operation.
- Time to be added for weather that differs from the standard condition.
In standard conditions, we execute the tasks in a moderate climate (i.e. With average temperatures between 5° C to 40° C) and winds less than 30km/hour.
To calculate the materials needed to build this base, read the post on materials inventory.
In the next publication, we will develop an example of how to calculate the cost per hour of a pickup truck.
Example of Direct Labor – Calculate Man Hours