Supervise the Planning of On-Site Medium Rise Building

This article provides insights on how to supervise the planning of on-site medium rise building or construction work. It includes task analysis of ground works and plastering, program critique, scheduling, and task compression. The article also discusses the impacts of compressing tasks and suggests alternative ways to compress the project schedule.

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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Course
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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

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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.

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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:

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Productivity constant = productivity constant for mortar preparation + productivity constant for
mortar application (including mason)
= 0.75 + 0.08 + 0.10 = 0.93 labour days per unit (m3)
c) Tradesman hours worked
Based on productivity constant, the number of tradesman hours worked for this task is calculated
as follows:
1m3 = 0.93 labour days
87m3 = (87 x 0.93) = 80.91 labour days
Assuming that one labour has 8 working hours, therefore 80.91 labour days will have:
80.91 x 8 = 648 hours
d) Suitable gang size
The suitable gang size for this task is 21. This includes 1 supervisor, 10 masons and 10 unskilled
labourers.
e) Needed time
Based on the above gang size of 10 masons, the required time to complete this task is as follows:
1 mason = 33m2 per day
10 masons = 10 x 33 = 330m2 per day
330m2 = 1 day
5800m2 = (5800 x 1)/ 330 = 17.58 ≈ 18 days

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f) Review of task
The sequence of the task is okay because this is a task that has to be done after completing
ground works, concrete works, masonry works, metal works, hydraulics, electrical and
mechanical works, water proofing works, PC items works and roofing works. From the
calculations above, this task can be completed within 18 days as opposed to 31 days that have
been set allowed in the program activity schedule. Therefore if I had to make any changes, I
would recommend that the number of gang for this task be 21 (1 supervisor or foreman, 10
masons and 10 unskilled labourers). Also, I would ensure that all the necessary materials and
equipment/tools for plastering are available on time to avoid any delays. I would make these
changes because they would help in completing the project faster, which has positive cost
implications.
Part 2: Critique the program provided
This program is generally apposite as it encompasses all tasks that have to be completed
in this project. Additionally, the tasks have been arranged in the right order in which they have to
be completed. This is very important as it helps in avoiding delays or demolitions as the project
progresses. However, the project program is only linear. This is a major disadvantage to project
delivery as it does not allow capitalizing on fast-tracking or completing tasks in a parallel way
(Agrama, 2011). From this program, most tasks can only be started after their predecessors have
been finished. This means that there is no room for faster construction processes such as
prefabrication or starting a task earlier as long as it does not interfere with its predecessors or
successors. Many construction companies nowadays use technology to reduce project delivery
period. As such, they avoid linear programs because they do not allow performing activities
concurrently. For instance, when the masonry subcontractors are doing the walling, the roofing

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subcontractor can be concurrently prefabricating the metal roof so that it gets installed
immediately the wall is completed. Prefabrication has become a major technique of reducing
time and cost in construction industry (Chiu, 2012). In general, linear programs are suitable for
construction projects with repetitive tasks (Kannan & Senthil, 2014), which is not the case for
this project.
The duration allowed for most of the tasks in this program also seems to be inaccurate i.e.
it is either less or more. Inaccurate estimation of duration has significant impacts on the project
including costs. If a task is allocated less time, it will affect completion *of succeeding tasks thus
extending the project duration. If it is allocated more time, some workers or equipment may
remain idle at some point due to lack of raw materials because delivery period has not yet
reached. Therefore this program has to be changed so that estimation of duration for each task is
computed more accurately. Researchers have developed numerous methods that can be used for
accurate estimation of project schedule (Zha & Zhang, 2014); (Zhang & Sun, 2008). These
methods include Monte Carlo simulation and Monroe method (Castro, et al., 2008);
(Kirytopoulos, et al., 2008). One of the approaches that these techniques apply is creating
simulation models of the project schedule so as to maximize every resource available (especially
time, workers and equipment).
Last but not least, it would have been better if the program was supported by a Gantt
chart. A Gantt chart is a better tool of representing a project schedule as it shows the logical
order of all tasks, duration of these tasks, connection between tasks, and how tasks depend on
each other. This also helps in identifying tasks that can be started at any time without causing an
interference to others (MacDonald, 2016).
Part 3

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Scheduling is very important in project implementation and management as it can break
or make a project (Katz, 2010). However, many stakeholders in the construction industry
understate realistic and optimistic scheduling (Linman, 2013). The schedule provided for this
project is both realistic and optimistic. It is realistic because it has been adequately planned. The
schedule captures all tasks with their estimated duration. Looking at the duration allocated for
each take, it seems not to have been done randomly but there were considerable efforts made to
estimate the time each task will take to be completed.
It is optimistic because all task have been systematically organized in the order from the
first to the last. This shows how the tasks will follow each other in the order of completion.
Based on this, the project team is hopeful that the schedule will help them implement and
complete the project successfully. But despite it being both realistic and optimistic, the project is
still exposed to uncertainty, which is inevitable in construction projects (Liu, 2012).
Nevertheless, the information provided in the schedule is not sufficient to determine if the
schedule is applicable in real-life situations. In construction industry, uncertainties cannot be
avoided. This requires scheduling to consider factors, such as bad weather, sickness of workers,
public holidays, unexpected political tensions, etc., which may cause delays.
Part 4
Yes, I would accept this program but I would do a few things before providing it to the
client or architect. The reason why I would accept the program is because it shows the systematic
procedure that has to be followed in completing each task of the project. It encompasses also
tasks and their estimated duration for completion. The first thing would be to recalculate the
duration allowed for each task. I would find a suitable project scheduling software, model or

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technique to do this task. Secondly, I would create a simulation model for this program to
determine its applicability in real-life situation. I would then do any necessary changes to ensure
that the program is practical in real life situation. Last but not least, I would create a Gantt chart
for this program.
Part 5: Task compression
Task compression is always necessary especially when the project experiences stringent
timelines (Moselhi & Roofigari-Esfahan, 2012); (Webb, et al., 2015). However, the compression
has numerous time, cost, safety and quality implications.
Task 1: Ground works
a) Time cost and compression impacts of working overtime each day
Depending on the number of overtime hours worked every day, the number of day to
complete ground works would be less than 19 days. Also depending on compression technique
applied, the cost of completing ground works would definitely be more than the estimated
$112,500. Other possible impacts of compressing this task include: fatigue of workers, injuries,
accidents, near misses of excavators, damage or wear & tear of machines and equipment, and
quality defects.
b) Time cost and compression impacts of working 6 days per week
This would have the same impacts as above. The task would be completed in less than 19
days and the cost of completing task would exceed the estimated $112,500.
c) Other ways to compress the project schedule

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Other ways of compressing the task include: crashing and fast-tracking. Crashing means
adding resources to activities such as leasing more excavators and dumpers/tractors and
employing more excavator operators, damper/tractor drivers and unskilled labourers. Fast-
tracking means completing activities in a parallel order instead of linear. Other techniques
include: using additional work shifts, avoiding mistakes by enhancing supervision, use of more
specialized crew, pre-work staff briefing, participative management, avoiding interruptions,
ensuring just-in-time delivery of materials, improving maintenance of tools and equipment, and
providing workers with incentives (Mansur, et al., 2015). The main disadvantage of these
techniques is that it increases cost of completing the task.
Task 2: Plastering
a) Time cost and compression impacts of working overtime each day
Depending on the number of overtime hours worked every day, the number of days needed to
complete plastering work would be less than 18 days. Also depending on compression technique
applied, the cost of completing ground works would definitely be more than the estimated
$144,100. Other possible impacts of compressing this task include: fatigue of workers, slips and
falls especially when working at height and quality defects.
b) Time cost and compression impacts of working 6 days per week
This would have the same impacts as above. The task would be completed in less than 18
days and the cost of completing task would exceed the estimated $114,100.
c) Other ways to compress the project schedule

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There are several other ways of compressing the task. One of them is crashing. This
technique involves adding resources to activities such as employing more masons and unskilled
labourers, ensuring perfection in the first place, adding more plastering tools. Another technique
is fast-tracking. This means completing activities in a parallel order instead of linear. Other
techniques include: using additional work shifts, use of more specialized crew, pre-work staff
briefing, participative management, avoiding interruptions, ensuring just-in-time delivery of
materials, providing workers with incentives and using alternative plastering methods. Just like
for ground works, the main disadvantage of these techniques is that it increases cost of
completing plastering task.
References
Agrama, F., 2011. Linear projects scheduling using spreadsheets features. Alexandria Engineering
Journal, 50(2), pp. 179-185.
Castro, J., Gomez, D. & Tejada, J., 2008. A rule for slack allocation proportional to the duration in a PERT
network. European Journal of Operational Research, 187(2), pp. 556-570.
Chiu, S. T., 2012. An Alaysis On: The Potential of Prefabricated Construction Industry, Vancouver:
University of British Columbia Library.
Kannan, S. & Senthil, R., 2014. Production based scheduling method for linear construction in road
projects. KSCE Journal of Civil Engineering , 18(5), pp. 1292-1301.
Katz, A., 2010. How to Achieve a More Realistic Schedule in Your Project Planning. [Online]
Available at: https://www.mpug.com/articles/how-to-achieve-a-more-realistic-schedule-in-your-project-
planning/
[Accessed 3 May 2018].
Kharrazi, 2017. Excavator and Its Productivity Count. [Online]
Available at: https://steemit.com/engineering/@kharrazi/excavator-and-calculate-its-productivity
[Accessed 3 May 2018].

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Kirytopoulos, K., Leopoulos, V. & Diamantas, V., 2008. Diamantas, PERT vs. Monte Carlo Simulation
along with the suitable distribution effect. International Journal of Project Organization and
Management, 1(1), pp. 24-46.
Linman, D., 2013. Developing A More Realistic Project Schedule. [Online]
Available at: http://www.mymanagementguide.com/develop-realistic-project-schedule/
[Accessed 3 May 2018].
Liu, J., 2012. Schedule Uncertainty Control: A Literature Review. Physics Procedia, Volume 33, pp. 1842-
1848.
MacDonald, J., 2016. How to Make Sure Your Project Timeline is Realistic. [Online]
Available at: https://www.business2community.com/strategy/make-sure-project-timeline-realistic-
01478998
[Accessed 3 May 2018].
Mansur, S., Mohamad zin, R. & Sea, E., 2015. Impact of Unplanned Schedule Compression on Project
Cost. Kuala Lumpur, Asia-Pacific Structural Engineering and Construction Conference .
Moselhi, O. & Roofigari-Esfahan, N., 2012. Compression of Project Schedules using the Analytical
Hierarchy Process. Multi-Criteria Decision Analysis, 19(1-2), pp. 67-78.
The Constructor, 2017. Labor Requirement for Various Construction Works. [Online]
Available at: https://theconstructor.org/tips/labor-requirement-building-construction-works/6906/
[Accessed 3 May 2018].
Webb, C., Gao, L. & Song, L., 2015. Schedule Compression Impact on Construction Project Safety.
Frontiers of Engineering Management, 2(4), pp. 344-350.
Zha, H. & Zhang, L., 2014. Scheduling Projects with Multiskill Learning Effect. The Scientific World
Journal, Volume 2014, pp. 1-7.
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Project. Science & Technology Progress and Policy, 25(10), pp. 94-96.