Supervise the Planning of On-Site Medium Rise Building

Supervise the Planning of On-Site Medium Rise Building 1
SUPERVISE THE PLANNING OF ON-SITE MEDIUM RISE BUILDING OR
CONSTRUCTION WORK
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Supervise the Planning of On-Site Medium Rise Building 2
Supervise the Planning of On-site Medium Rise Building or Construction Work
Part 1: Analysis of two tasks from different trades
Task 1: Ground works
This task entails bulk excavation (removal) of rocks or soil and other materials (OTR) on site,
moving the excavated materials, trimming, leveling and backfilling as needed.
a) Measured material quantities
The total measured material quantity of ground work in this project is 4,500 m2. This
comprises of volumes of all materials that will be excavated on the site and either used as
backfill or carted away for disposal from the site. Assuming that the average depth of excavation
is 0.5m then the volume of this work becomes: 4500m2 x 1.5m = 6,750m3.
b) Productivity constants
The productivity constant for ground works entails productivity constants for excavation over
areas (and removal of the cut), excavation in trenches (and removal of cut) and filling, returning
and ramming of excavated areas in layers. The total productivity constant for ground work in this
project is as follows:
Productivity constant = productivity constant for excavation over area + productivity constant in
trenches + productivity constant for filling, returning and ramming
= 0.62 + 0.50 + 0.25 = 1.37 labour days per unit (m3). It is important to note that his includes
travel, transport, storage, delivery and disposal of excavated materials (The Constructor, 2017).
c) Tradesman hours worked

Supervise the Planning of On-Site Medium Rise Building 3
From the productivity constant calculated above, the number of tradesman hours worked for this
task is calculated as follows:
1m3 = 1.37 labour days
2250m3 = (6750 x 1.37) = 9,247.5 labour days
Assuming that one labour has 8 working hours, therefore 9247.5 labour days will have:
9,247.5 x 8 = 93,980 hours
d) Suitable gang size
The suitable gang size for this task is 18. This includes 1 supervisor, 2 excavator operators, 5
tractor/dumper drivers and 10 unskilled labourers.
e) Needed time
Based on the above gang size of 2 excavator operators, the required time to complete this task is
as follows:
Assume that the excavator capacity is 100m3 per hour and the operator works for 4 hours per day
(considering rest hours),
In 1 day, the two excavators will have excavated (2 x 100 x 4) = 800m3
800m3 = 1 day
6750m3 = (6750 x 1)/ 800 = 8.4375 ≈ 9 days
Besides excavation, there is backfilling some areas as required, moving excavated materials to
disposal areas, trimming, leveling and ramming the ground. These tasks are estimated to take 10
days. Therefore total time required to complete this task is (9 + 10) = 19 days.

Supervise the Planning of On-Site Medium Rise Building 4
f) Review of task
This being among the very first task on site, its sequence is very simple and clear. The only
predecessor is preliminaries, which include preparing accommodation facilities for workers, site
fencing, site clearing, installation or moving of temporary services and removal of rubbish. The
sequence of the task is appropriate for successful completion of the task. From the calculations
above this task can be completed within 19 days, as opposed to 20 days that have been allowed
in the program activity schedule. Therefore if I had to make changes, I would recommend that
the number of gang for this task be 18 (1 supervisor, 2 excavator operators, 5 tractor/dumper
drivers and 10 unskilled labourers). If there was adequate resources, I would recommend to
select an excavator with a greater capacity. Greater capacity increases productivity of the
excavator (Kharrazi, 2017). This would help in reducing the number of days needed to complete
the task thus reducing project delivery period.
Task 2: Plastering – cement render to internal
a) Measured material quantities
The total measured material quantity of cement rendering to internal walls in this project is
5,800 m2. This comprises of cement and sand materials that will be required to plaster the
internal walls of the building. Assuming that the thickness of plaster is 0.015m then the volume
of this work becomes: 5800m2 x 0.015m = 87m3.
b) Productivity constants
The productivity constant for plastering work entails productivity constants for mortar
preparation and application. The total productivity constant for plastering work in this project is
as follows: