Volume is the key!
PURPOSE OF EXCAVATION
For every construction in the Philippines after site is cleared from any sorts of obstruction and placement of batter boards, comes next is your "excavation", the digging process in preparation for the location of your footings/wall footings or so called foundations.
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| batter boards and excavation |
Not limited for foundations, it can be for swimming pool areas, for your septic tank, for highly elevated areas that requires to cut some portion of soil if lot located on hills or mountains.
Note that for a two storey residential structure no soil testing is made, but for 3 storey and beyond will be required to conduct soil analysis to check its properties if it has the capacity to counter the overall load or pressure to be brought by the proposed structure.
HOW BIG AND DEEP IS YOUR EXCAVATION
Excavation size will be based as per plan and as per design by your Structural Engineer, this includes how deep will be your foundation will be located below ground level.
Nonetheless, as owner knowing this at least gives you a general idea on how much will it cost you, the number of manpower needed and how many days it would take them to complete the excavation.
Sample productivity rate:
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| image from philconprices.com |
To illustrate:
Say we have a total of 13cu.m volume that needs to be excavated for your footings.
Structural excavation by hand 6MH/cu.m (PR)
Total Men to excavate: 3 manpower
Hours per day: 8hrs (common number of work hours per day)
MHtotal = PR x volume = 6 x 13 = 78 total man-hours
Divide MH with number of men to excavate = 78/3 = 26hours total hours to finish the job
Since they only work 8 hours a day, divide 26/hours with 8 hours to get number of days to complete
Number of days = 26/8 = 3.25 days to complete the excavation of 13cu.m with 3 manpower
Optional if you wish to add contingency in case of weather disturbances that may delay the excavation.
LABOR COST
Depending on rate per location: Let's say 450php per day per head
therefore:
3 men x 600php/day x 3.25 days = 5,8550php
This is just the estimate for "excavation" and you may opt to add additional 30-35% for the backfill works or make a separate computation following the same process but this time changing the MH productivity rate of 6MH/cu.m to 5MH/cu.m
Sample Excavation Calculator using excel:
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| excavation excel calculator |
File copy check in Download Section.
